Powered by Deep Web Technologies
Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Design Wind Speed  

Science Journals Connector (OSTI)

Wind is characterized by various different parameters. They include the following items: (1) wind speed, such as the mean wind speed and maximum instantaneous wind speed; (2) wind direction such as the azimuth di...

Yozo Fujino; Kichiro Kimura; Hiroshi Tanaka

2012-01-01T23:59:59.000Z

2

Detecting and evaluating climate change effect on frequency analysis of wind speed  

Science Journals Connector (OSTI)

The purpose of this study is to detect an existing trend in wind speed and to evaluate the effect of climate change on frequency analysis of wind speed in Iran. Twenty-two stations with a length of records higher than 50 years have been selected. Five statistical methods that were used to detect the trends are Mann-Kendall, Spearman-Conley, cumulative deviation, autocorrelation coefficient and regression analysis. It is revealed that 11 stations have a positive or a negative trend while the rest has no trend. Climate change leads to a lack of homogeneity in a number of stations. Therefore, it is impossible to use frequency analysis for those stations. One appropriate approach is dividing the stations into two smaller parts, and for each part, frequency analysis could be taken if the part is homogenous.

Saeid Eslamian; Hadi Hassanzadeh; Mohammad Javad Khordadi

2009-01-01T23:59:59.000Z

3

wind speed | OpenEI  

Open Energy Info (EERE)

speed speed Dataset Summary Description GIS data for offshore wind speed (meters/second). Specified to Exclusive Economic Zones (EEZ).Wind resource based on NOAA blended sea winds and monthly wind speed at 30km resolution, using a 0.11 wind sheer to extrapolate 10m - 90m. Annual average >= 10 months of data, no nulls. Source National Renewable Energy Laboratory (NREL) Date Released Unknown Date Updated Unknown Keywords GIS global NOAA NREL offshore wind wind speed Data application/zip icon Download Shapefile (zip, 18.5 MiB) Quality Metrics Level of Review Some Review Comment Temporal and Spatial Coverage Frequency Time Period License License Other or unspecified, see optional comment below Comment Please cite NREL and NOAA Rate this dataset Usefulness of the metadata

4

Forecasting Solar Wind Speeds  

E-Print Network [OSTI]

By explicitly taking into account effects of Alfven waves, I derive from a simple energetics argument a fundamental relation which predicts solar wind (SW) speeds in the vicinity of the earth from physical properties on the sun. Kojima et al. recently found from their observations that a ratio of surface magnetic field strength to an expansion factor of open magnetic flux tubes is a good indicator of the SW speed. I show by using the derived relation that this nice correlation is an evidence of the Alfven wave which accelerates SW in expanding flux tubes. The observations further require that fluctuation amplitudes of magnetic field lines at the surface should be almost universal in different coronal holes, which needs to be tested by future observations.

Takeru K. Suzuki

2006-02-03T23:59:59.000Z

5

Wind Speed Dependence of Single-Site Wave-Height Retrievals from High-Frequency Radars  

Science Journals Connector (OSTI)

Wave-height observations derived from single-site high-frequency (HF) radar backscattered Doppler spectra are generally recognized to be less accurate than overlapping radar techniques but can provide significantly larger sampling regions. The ...

Brian K. Haus; Lynn K. Shay; Paul A. Work; George Voulgaris; Rafael J. Ramos; Jorge Martinez-Pedraja

2010-08-01T23:59:59.000Z

6

OpenEI - wind speed  

Open Energy Info (EERE)

NREL GIS Data: Global NREL GIS Data: Global Offshore Wind http://en.openei.org/datasets/node/869 GIS data for offshore wind speed (meters/second).  Specified to Exclusive Economic Zones (EEZ).Wind resource based on NOAA blended sea winds and monthly wind speed at 30km resolution, using a 0.11 wind sheer to extrapolate 10m - 90m.  Annual average  >= 10 months of data, no nulls. License

Type of License:  Other (please specify below)

7

Wind speed vertical distribution at Mt. Graham  

E-Print Network [OSTI]

The characterization of the wind speed vertical distribution V(h) is fundamental for an astronomical site for many different reasons: (1) the wind speed shear contributes to trigger optical turbulence in the whole troposphere, (2) a few of the astroclimatic parameters such as the wavefront coherence time (tau_0) depends directly on V(h), (3) the equivalent velocity V_0, controlling the frequency at which the adaptive optics systems have to run to work properly, depends on the vertical distribution of the wind speed and optical turbulence. Also, a too strong wind speed near the ground can introduce vibrations in the telescope structures. The wind speed at a precise pressure (200 hPa) has frequently been used to retrieve indications concerning the tau_0 and the frequency limits imposed to all instrumentation based on adaptive optics systems, but more recently it has been proved that V_200 (wind speed at 200 hPa) alone is not sufficient to provide exhaustive elements concerning this topic and that the vertical d...

Hagelin, S; Lascaux, F

2010-01-01T23:59:59.000Z

8

Forecasting wind speed financial return  

E-Print Network [OSTI]

The prediction of wind speed is very important when dealing with the production of energy through wind turbines. In this paper, we show a new nonparametric model, based on semi-Markov chains, to predict wind speed. Particularly we use an indexed semi-Markov model that has been shown to be able to reproduce accurately the statistical behavior of wind speed. The model is used to forecast, one step ahead, wind speed. In order to check the validity of the model we show, as indicator of goodness, the root mean square error and mean absolute error between real data and predicted ones. We also compare our forecasting results with those of a persistence model. At last, we show an application of the model to predict financial indicators like the Internal Rate of Return, Duration and Convexity.

D'Amico, Guglielmo; Prattico, Flavio

2013-01-01T23:59:59.000Z

9

Surface wind speed distributions| Implications for climate and wind power.  

E-Print Network [OSTI]

?? Surface constituent and energy fluxes, and wind power depend non-linearly on wind speed and are sensitive to the tails of the wind distribution. Until… (more)

Capps, Scott Blair

2010-01-01T23:59:59.000Z

10

Wind Speed Prediction Via Time Series Modeling.  

E-Print Network [OSTI]

??Projected construction of nearby wind farms motivates this study of statistical forecasting of wind speed, for which accurate prediction is critically important to the fluid… (more)

Alexander, Daniel

2009-01-01T23:59:59.000Z

11

Estimation of the Design Wind Speed  

Science Journals Connector (OSTI)

The modern approach to the specification of the design wind speed favours the explicit format which directly presents the design value of the wind speed instead of hiding the value behind the product of the chara...

Michael Kasperski

2013-01-01T23:59:59.000Z

12

Wind speed vertical distribution at Mt Graham  

Science Journals Connector (OSTI)

......October 2010 research-article Papers Wind speed vertical distribution at Mt Graham...characterization of the vertical distribution of wind speed, V(h), is fundamental for an...many different reasons: (i) the wind speed shear contributes to trigger optical......

S. Hagelin; E. Masciadri; F. Lascaux

2010-10-01T23:59:59.000Z

13

Wind Speed Forecasting for Power System Operation  

E-Print Network [OSTI]

In order to support large-scale integration of wind power into current electric energy system, accurate wind speed forecasting is essential, because the high variation and limited predictability of wind pose profound challenges to the power system...

Zhu, Xinxin

2013-07-22T23:59:59.000Z

14

Estimation of Wind Speed in Connection to a Wind Turbine  

E-Print Network [OSTI]

horizontal axis wind power plant with rated power 750 KW. The plant has a three bladed rotor and an automatic is shown in Figure 1 demand Drive train Generator Rotor Wind speed Power demand Grid Power Controller PitchEstimation of Wind Speed in Connection to a Wind Turbine X. Ma #3; , N. K. Poulsen #3; , H. Bindner

15

Wind Speed Data Analysis using Wavelet Transform  

E-Print Network [OSTI]

Abstract—Renewable energy systems are becoming a topic of great interest and investment in the world. In recent years wind power generation has experienced a very fast development in the whole world. For planning and successful implementations of good wind power plant projects, wind potential measurements are required. In these projects, of great importance is the effective choice of the micro location for wind potential measurements, installation of the measurement station with the appropriate measuring equipment, its maintenance and analysis of the gained data on wind potential characteristics. In this paper, a wavelet transform has been applied to analyze the wind speed data in the context of insight in the characteristics of the wind and the selection of suitable locations that could be the subject of a wind farm construction. This approach shows that it can be a useful tool in investigation of wind potential. Keywords—Wind potential, Wind speed data, Wavelet transform.

S. Avdakovic; A. Lukac; A. Nuhanovic; M. Music

16

Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine  

E-Print Network [OSTI]

Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine-Frequency Control (LFC) is gradually shifted to Variable Speed Wind Turbines (VSWTs). In order to equip VSWT@et.aau.dk Abstract--In near future, with high penetration of Wind Energy (WE) in power system, the burden of Load

Silva, Filipe Faria Da

17

Low frequency noise from MW wind turbines --mechanisms of generation  

E-Print Network [OSTI]

Low frequency noise from MW wind turbines -- mechanisms of generation and its modeling Helge MW wind turbines -- mechanisms of generation and its modeling Department: Department of Wind Energy 3.6MW turbine 12 3.2 Noise as function of wind speed 12 3.3 Noise as function of rotor

18

Wind: wind speed and wind power density maps at 10m and 50m above surface  

Open Energy Info (EERE)

maps at 10m and 50m above surface maps at 10m and 50m above surface and 0.25 degree resolution for global oceans from NREL Dataset Summary Description (Abstract): Raster GIS ASCII data files of wind speed and wind power density at 10 and 50 m heights. Global data of offshore wind resource as generated by NASA's QuikSCAT SeaWinds scatterometer. (Purpose): To provide information on the wind resource potential of offshore areas. Source NREL Date Released December 31st, 2005 (9 years ago) Date Updated November 01st, 2007 (7 years ago) Keywords GEF GIS NASA NREL SWERA UNEP wind Data application/zip icon Download Maps (zip, 36.3 MiB) Quality Metrics Level of Review Some Review Comment Temporal and Spatial Coverage Frequency Time Period 2000 - 2004 License License Other or unspecified, see optional comment below

19

Wind: wind speed and wind power density GIS data at 10m and 50m above  

Open Energy Info (EERE)

10m and 50m above 10m and 50m above surface and 0.25 degree resolution for global oceans from NREL Dataset Summary Description (Abstract): Raster GIS ASCII data files of wind speed and wind power density at 10 and 50 m heights. Global data of offshore wind resource as generated by NASA's QuikScat SeaWinds scatterometer. (Purpose): To provide information on the wind resource potential of offshore areas. Source NREL Date Released December 31st, 2005 (9 years ago) Date Updated November 01st, 2007 (7 years ago) Keywords GEF GIS NASA NREL ocean offshore QuikScat SWERA UNEP wind Data application/msword icon Download Documentation (doc, 53.8 KiB) application/zip icon Download Data (zip, 41 MiB) Quality Metrics Level of Review Some Review Comment Temporal and Spatial Coverage Frequency Time Period 01/01/2000 - 12/31/2004

20

Wind speed estimation using multilayer perceptron  

Science Journals Connector (OSTI)

Abstract Wind speed knowledge is prerequisite in the siting of wind turbines. In consequence the wind energy use requires meticulous and specified knowledge of the wind characteristics at a location. This paper presents a method for determining the annual average wind speed at a complex terrain site by using neural networks, when only short term data are available for that site. This information is useful for preliminary calculations of the wind resource at a remote area having only a short time period of wind measurements measurement in a site. Artificial neural networks are useful for implementing non-linear process variables over time, and therefore are a useful tool for estimating the wind speed. The neural network used is multilayer perceptron with three layers and the supervised learning algorithm used is backpropagation. The inputs used in the neural network were wind speed and direction data from a single station, and the training patterns used correspond to sixty days data. The results obtained by simulating the annual average wind speed at the selected site based on data from nearby stations with correlation coefficients above 0.5 were satisfactory, compared with actual values. Reliable estimations were obtained, with errors below 6%.

Ramón Velo; Paz López; Francisco Maseda

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Wind: wind speed and wind power density maps at 10m and 50m above...  

Open Energy Info (EERE)

files of wind speed and wind power density at 10 and 50 m heights. Global data of offshore wind resource as generated by NASA's QuikSCAT SeaWinds scatterometer....

22

Wind: wind speed and wind power density GIS data at 10m and 50m...  

Open Energy Info (EERE)

files of wind speed and wind power density at 10 and 50 m heights. Global data of offshore wind resource as generated by NASA's QuikScat SeaWinds scatterometer....

23

LIDAR Wind Speed Measurements of Evolving Wind Fields  

SciTech Connect (OSTI)

Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feedforward control systems designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. Past studies have assumed Taylor's frozen turbulence hypothesis, which implies that turbulence remains unchanged as it advects downwind at the mean wind speed. With Taylor's hypothesis applied, the only source of wind speed measurement error is distortion caused by the LIDAR. This study introduces wind evolution, characterized by the longitudinal coherence of the wind, to LIDAR measurement simulations to create a more realistic measurement model. A simple model of wind evolution is applied to a frozen wind field used in previous studies to investigate the effects of varying the intensity of wind evolution. LIDAR measurements are also evaluated with a large eddy simulation of a stable boundary layer provided by the National Center for Atmospheric Research. Simulation results show the combined effects of LIDAR errors and wind evolution for realistic turbine-mounted LIDAR measurement scenarios.

Simley, E.; Pao, L. Y.

2012-07-01T23:59:59.000Z

24

Ris-R-1563(EN) ACCUWIND -Accurate Wind Speed  

E-Print Network [OSTI]

Risø-R-1563(EN) ACCUWIND - Accurate Wind Speed Measurements in Wind Energy Summary Report Troels (RIS�) Title: ACCUWIND ­ Accurate Wind Speed Measurements in Wind Energy ­ Summary Report Department speed measurement in wind energy. It is being applied in high numbers around the world for wind energy

25

Assessment of Wind Speed Dependent Prediction Error  

Science Journals Connector (OSTI)

The investigations in this chapter follow the idea that the prediction error quantitatively depends on the meteorological situation that has to be predicted. As a first approach the wind speed as a main indicator...

Dr. Matthias Lange; Dr. Ulrich Focken

2006-01-01T23:59:59.000Z

26

Sampling Wind Data for Mean Wind Speed Estimation  

Science Journals Connector (OSTI)

Two sampling techniques are applied to wind data at 3 h intervals for six stations in the Great Plains region in the United States in order to investigate the reduction in the number of data needed to estimate the mean wind speed. One-in-k ...

Mark Jong; Gary Thomann

1981-03-01T23:59:59.000Z

27

Unsafe at Any (Wind) Speed?  

Science Journals Connector (OSTI)

The goal of this research was to examine the relative safety and stability of stationary motor vehicles exposed to severe winds. The focus was on private passenger vehicles. 1) The behavior of two instrumented storm-chase vehicles that were ...

Thomas Schmidlin; Barbara Hammer; Paul King; Yuichi Ono; L. Scott Miller; Gregory Thumann

2002-12-01T23:59:59.000Z

28

Time Series Models to Simulate and Forecast Wind Speed and Wind Power  

Science Journals Connector (OSTI)

A general approach for modeling wind speed and wind power is described. Because wind power is a function of wind speed, the methodology is based on the development of a model of wind speed. Values of wind power are estimated by applying the ...

Barbara G. Brown; Richard W. Katz; Allan H. Murphy

1984-08-01T23:59:59.000Z

29

LIDAR Wind Speed Measurements of Evolving Wind Fields  

SciTech Connect (OSTI)

Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feedforward control systems that are designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. Past studies have assumed the validity of physicist G.I. Taylor's 1938 frozen turbulence hypothesis, which implies that turbulence remains unchanged as it advects downwind at the mean wind speed. With Taylor's hypothesis applied, the only source of wind speed measurement error is distortion caused by the LIDAR. This study introduces wind evolution, characterized by the longitudinal coherence of the wind, to LIDAR measurement simulations using the National Renewable Energy Laboratory's (NREL's) 5-megawatt turbine model to create a more realistic measurement model. A simple model of wind evolution was applied to a frozen wind field that was used in previous studies to investigate the effects of varying the intensity of wind evolution. LIDAR measurements were also evaluated using a large eddy simulation (LES) of a stable boundary layer that was provided by the National Center for Atmospheric Research. The LIDAR measurement scenario investigated consists of a hub-mounted LIDAR that scans a circle of points upwind of the turbine in order to estimate the wind speed component in the mean wind direction. Different combinations of the preview distance that is located upwind of the rotor and the radius of the scan circle were analyzed. It was found that the dominant source of measurement error for short preview distances is the detection of transverse and vertical wind speeds from the line-of-sight LIDAR measurement. It was discovered in previous studies that, in the absence of wind evolution, the dominant source of error for large preview distances is the spatial averaging caused by the LIDAR's sampling volume. However, by introducing wind evolution, the dominant source of error for large preview distances was found to be the coherence loss caused by evolving turbulence. Different measurement geometries were compared using the bandwidth for which the measurement coherence remained above 0.5 and also the area under the measurement coherence curve. Results showed that, by increasing the intensity of wind evolution, the measurement coherence decreases. Using the coherence bandwidth metric, the optimal preview distance for a fixed-scan radius remained almost constant for low and moderate amounts of wind evolution. For the wind field with the simple wind evolution model introduced, the optimal preview distance for a scan radius of 75% blade span (47.25 meters) was found to be 80 meters. Using the LES wind field, the optimal preview distance was 65 meters. When comparing scan geometries using the area under the coherence curve, results showed that, as the intensity of wind evolution increases, the optimal preview distance decreases.

Simley, E.; Pao, L. Y.; Kelley, N.; Jonkman, B.; Frehlich, R.

2012-01-01T23:59:59.000Z

30

Wind dependence of deep ocean ambient noise at low frequencies  

Science Journals Connector (OSTI)

A series of experiments has been carried out using a vertical line array to measure low?frequency ambient noise at deep ocean sites in the Northeast Pacific Ocean. Data in the band from 13 to 300 Hz were processed to obtain the array response directed vertically upward in order to study the noise due to local winds. The results indicate that there are two regimes of behavior depending on the wind speed v with the transition occurring at the onset of wave breaking v?10 kn. The noise level (NL) for a specific wind noise process was related to a power n of the wind speed according to the relationship NL=B+20n?log?v and the model parameters were obtained by fitting the data. The average value over the band was n=0.3 for wind speeds wind?generated noise was determined over the low?frequency band for wind speeds from 10–30 kn. The values are consistent with those of a recent analysis of available noise data [Kewley e t a l. ‘‘Low?frequency wind?generated ambient noise source levels ’’ J. Acoust. Soc. Am. 8 8 1894–1902 (1990)] and the model provides good agreement with wind noise measurements obtained with omni hydrophones in the southern oceans.

N. R. Chapman; J. W. Cornish

1993-01-01T23:59:59.000Z

31

Pitch and torque control of variable speed wind turbines.  

E-Print Network [OSTI]

??In this thesis the torque, speed and pitch angle control of variable speed wind turbine is investigated. In particular, it concentrates on the extraction of… (more)

Kulka, Arkadiusz

2004-01-01T23:59:59.000Z

32

The parent wind speed distribution: Why Weibull?  

Science Journals Connector (OSTI)

Abstract Part 1: The Weibull distribution has been used for many years to fit parent wind data. It is a particularly good fit to mean wind speed data arising from a wind climate dominated by temperate depressions. This good fit is practically useful, but intellectually not very satisfactory, because the familiar or Forward Weibull distribution is a purely empirical construct and there have seemed to be no reasons, grounded in either atmospheric physics or probability theory, why wind speeds should conform to this model. This paper introduces another distribution, the Offset Elliptical Normal (OEN) model, which has some justification in terms of probability theory and appears to form a more plausible model for mean wind speeds. It is shown that, over the entire practical range from everyday values to 1:10,000 year extremes and beyond, this new distribution matches a Weibull distribution so closely, that the Weibull can be regarded as not just empirical, but as an effective surrogate for the new distribution. One Weibull distribution corresponds to a whole family of the new distribution. Part 2: The assumptions of Harris’ Offset Elliptical Normal (OEN) model are verified using direct vector analysis of hourly wind observations at two, widely separated UK stations. The Jenkinson–Lamb index is found not to be effective in separating UK wind observations by causal mechanism for individual analysis. Fitting to the marginal distributions of wind speed and direction is shown not to be practicable owing to the information on their joint action that has been lost. Instead, an optimisation methodology is used to fit multiple disjoint OEN models to the joint PDF of the observed wind vectors, without prior separation of the observations. For Marham, Norfolk, a single OEN is sufficient, but two is marginally better. For Tiree, Inner Hebrides, two disjoint \\{OENs\\} are sufficient, but three is marginally better. For Changi, Singapore, three disjoint \\{OENs\\} correspond well with the three seasonal climates (inter-monsoon, “wet” NE monsoon and “dry” SW monsoon). For Rome (Ciampino) the component that dominates in the upper tail is shown to include downbursts from thunderstorms or other strong convective events.

R. Ian Harris; Nicholas J. Cook

2014-01-01T23:59:59.000Z

33

Extreme wind climate modeling of some locations in India for the specification of the design wind speed of structures  

Science Journals Connector (OSTI)

The wind load on a structure is proportional to the square of the wind speed. Extreme wind climate modeling should be required for specifying the design wind speed of structures. Extreme wind speeds for a storm t...

Arnab Sarkar; Navneet Kumar; Debojyoti Mitra

2014-06-01T23:59:59.000Z

34

Improving WRF-ARW Wind Speed Predictions using Genetic Programming  

Science Journals Connector (OSTI)

Numerical weather prediction models can produce wind speed forecasts at a very high space resolution. ... that GP is able to successfully downscale the wind speed predictions, reducing significantly the inherent ...

Giovanna Martinez-Arellano; Lars Nolle…

2012-01-01T23:59:59.000Z

35

Wind-Speed Undulations Over Swell: Field Experiment and Interpretation  

Science Journals Connector (OSTI)

Results of field measurements of the swell-induced undulation of the wind speed taken from a Black Sea platform are presented. The wind speed and its fluctuations were measured at several ... m above the mean sea...

Y. P. Soloviev; V. N. Kudryavtsev

2010-09-01T23:59:59.000Z

36

Solar cycle dependence of global distribution of solar wind speed  

Science Journals Connector (OSTI)

A review is given of observational results concerning the solar cycle dependence of the global structure of solar wind speed distribution during the years from 1973 to 1987. Since observations of solar wind speed

Masayoshi Kojima; Takakiyo Kakinuma

1990-08-01T23:59:59.000Z

37

Photosynthetic Rate of a Plant Community and Wind Speed  

Science Journals Connector (OSTI)

The previous chapter illustrated not only that wind speed affects the photosynthetic rate, but also that ... single leaves, may be affected by the wind speed. Thus, to uncover facts about the...

Kazutoshi Yabuki

2004-01-01T23:59:59.000Z

38

Multiscale prediction of wind speed and output power for the wind farm  

Science Journals Connector (OSTI)

This paper focuses on establishing the multiscale prediction models for wind speed and power in wind farm by the average wind speed collected from the history records. Each type ... the predictive values of outpu...

Xiaolan Wang; Hui LI

2012-05-01T23:59:59.000Z

39

Simulation of Stochastic Fluctuating Wind Field Using the Wave Superposition Method with Random Frequencies  

Science Journals Connector (OSTI)

The wave superposition method is one of the effective methods to simulate the stochastic fluctuating wind field. The simulated wind speed samples with single-indexing frequencies are...T 0 = 2? · N/...

D. J. Han; J. J. Luo

2007-01-01T23:59:59.000Z

40

Offshore wind speed and wind power characteristics for ten locations in Aegean and Ionian Seas  

Science Journals Connector (OSTI)

This paper utilizes wind speed data measured at 3 and 10 ... and Aegean Seas to understand the behaviour of wind and thereafter energy yield at these stations using 5 MW rated power offshore wind turbine. With wind

HARALAMBOS S BAGIORGAS; GIOULI MIHALAKAKOU…

2012-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Globally competitive variable-speed wind turbines  

SciTech Connect (OSTI)

This paper focuses on the design issues which must be addressed if variable-speed wind turbines are to compete in the global marketplace. The paper examines how component-specific design decisions must be made on a system level if an optimized system is to be the result. The relationships among the blades, the generator and the utility interface are considered in detail, using the conceptual design of a 12 kW variable-speed wind turbine (the AOC 8/12) as a running example. The turbine is based on a direct-drive variable-reluctance generator (VRG), a single- or three-phase utility interface as appropriate, and a three-bladed rotor with fixed pitch. A preliminary turbine specification is provided, along with candidate power-speed curves and annual energy output. This paper documents the continuing development and commercialization of this technology which is being taken from the proof-of-concept stage and is now headed for field testing.

Torrey, D.A. [Rensselaer Polytechnic Institute, Troy, NY (United States); Childs, S.E.; Johnson, B.; Carter, J. [Atlantic Orient Corp., Norwich, VT (United States)

1995-12-31T23:59:59.000Z

42

Using ADCP Background Sound Levels to Estimate Wind Speed  

Science Journals Connector (OSTI)

It is well known that ambient sound is generated by wind through the process of wave breaking and bubble injection. The resulting sound levels are highly correlated with wind speed and, even though the physical process is not fully understood, ...

Len Zedel

2001-11-01T23:59:59.000Z

43

Correlation analysis for wind speed and failure rate of wind turbines using time series approach  

Science Journals Connector (OSTI)

The correlation between wind speed and failure rate (FR) of wind turbines is analyzed with time series approach. The time series of power index (PI) and FR of wind turbines are established based on historical data which are pretreated by singularity processing stationarity processing and wavelet de-noising. The trend variations of the time series are analyzed from both time domain and frequency domain by extracting the indicator functions including auto-correlation function cross-correlation function and spectral density function. A case study is given out to verify the validity of the model and the method which is based on the wind speed and failure data from January 1995 to December of 2002 in Nordjylland Denmark. Auto-correlation function and spectral density function show that time series of PI and FR have strong seasonal characteristics and quite similar periodicity while the cross-correlation function shows they keep high consistency and strong correlation. The results indicate that by calculating and monitoring PI the failure rule of wind turbines can be forecast which provides theoretical basis for preventive maintenance of wind turbines.

Chun Su; Quan Jin; Yequn Fu

2012-01-01T23:59:59.000Z

44

Estimation methods review and analysis of offshore extreme wind speeds and wind energy resources  

Science Journals Connector (OSTI)

Abstract Offshore wind resources are more abundant and stronger and they blow more consistently than land-based wind resources. While gale force winds are easier to hit on the sea, the strong wind vibration and wind loads may exert severe damage and shock to wind turbines and wind power grids, even resulting in power grid collapse. Thus, to develop offshore wind power, apart from accurate quantitative wind energy potential assessments, it is necessary to effectively estimate extreme wind speeds. Toward this purpose, this paper investigates the current status of extreme wind speeds and wind energy assessment from literature review. It turns out that much work on wind energy estimation has been performed, whereas relatively little research involves extreme wind speeds, the main challenge stemming from the limited availability of derived extreme winds. Then a GH method based on artificial intelligence optimization algorithms is developed to re-analyze future samples of extreme wind speeds. On the basis of the re-analyzed extreme samples, as well as the Generalized Extreme Value (GEV) and Gumbel models optimized by Cuckoo Search (CS) and Chaotic Particle Swarm Optimization (CPSO) algorithms, the potential risks of extreme wind speeds are conducted based on 23-year (1990–2012) historic wind speeds. Thus, in terms of wind speeds, a comprehensive estimation for offshore wind energy is initially implemented in Bohai Rim, China. The assessment shows that the study areas have high-strength wind power but are rarely subjected to extreme wind speeds, which implies that it is suitable for wind farm construction.

Jianzhou Wang; Shanshan Qin; Shiqiang Jin; Jie Wu

2015-01-01T23:59:59.000Z

45

A comparison of wind speed shears for frontal and undisturbed synoptic conditions  

Science Journals Connector (OSTI)

Wind speed shear parameters derived from data collected at ... conditions (cold frontal passage), all undisturbed winds, undisturbed high winds, and undisturbed low winds. The exponential values of the wind speed

Ching-Ming Sheih

46

Improved methodology for design of low wind speed specific wind turbine blades  

Science Journals Connector (OSTI)

Abstract The majority of wind power is currently produced on high wind speed sites, and the standard design of wind turbine blades has evolved to be structurally efficient under these conditions. Recently, sites with lower quality wind resources have begun to be considered for new wind farms. This study confirms the expectation that the standard high wind speed design process results in less efficient structures when used for low wind speed conditions, and that a low wind speed specific design process is able to yield structural improvements. A comparative structural analysis of generic blades from high and low wind speed turbines quantifies the differences in structural performance between high and low wind speed blades, and indicates the ways in which the standard design process should be modified to suit a low wind speed specific design. An improved design method specifically for low wind speed blades is proposed, with more emphasis on stiffness than in the standard high wind speed design. The improved design process results in a lighter and cheaper blade than the conventionally designed one, whilst still fulfilling the design requirements.

R.H. Barnes; E.V. Morozov; K. Shankar

2015-01-01T23:59:59.000Z

47

Reliability models of wind farms considering wind speed correlation and WTG outage  

Science Journals Connector (OSTI)

Abstract Wind speed correlation and wind turbine generator (WTG) outage are two factors affecting the reliability model of wind farms, but they are not addressed simultaneously in the existing literature. Meanwhile, WTG outage is reported to be dependent with wind speed to some extent. Therefore, the extended reliability models of wind farms incorporating both of these two factors and the dependency between WTG outage and wind speed are proposed in this paper. To consider the uncertainties and dependencies of wind speed and WTG failure, Copula method is applied to simulate correlated random variables representing for wind speed and the number of failed WTG units. Moreover, the linear apportioning technique is used to create multistate reliability models of wind farms from hourly wind power models. A number of sensitivity analyses on the modified IEEE RTS with wind power are conducted to validate the proposed reliability models for generation adequacy assessment. Case studies show that the generation adequacy indices increase with the correlation of wind speed and WTG forced outage rate (FOR). It is meaningful to point out that the effect of dependency between wind speed and WTG FOR on generation adequacy is minimal when WTG outages are independent, but it will be substantially larger when WTG outages are highly dependent. The proposed multistate reliability models of wind farms provide foundation for the reliability assessment of power systems with wind power integrated.

Fan Chen; Fangxing Li; Zhinong Wei; Guoqiang Sun; Jun Li

2015-01-01T23:59:59.000Z

48

0 Riso-R-434 Wind Speed and Direction  

E-Print Network [OSTI]

meteorological statistics for the area as it was considered a possible site for a nuclear power plant. \\ \\ Duringm I 0 Riso-R-434 t Wind Speed and Direction Changes due to Terrain Effects revealed-4000 Roskilde, Denmark May 1983 #12;RISĂ?-R-434 WIND SPEED AND DIRECTION CHANGES DUE TO TERRAIN EFFECTS

49

Ocean Wind Speed Climatology from Spaceborne SAR Imagery  

Science Journals Connector (OSTI)

Spaceborne synthetic aperture radar (SAR) imagery can make high-resolution (?500 m) ocean wind speed measurements. The authors anticipate reprocessing the full decade and a half of Radarsat-1 SAR imagery and generating a SAR wind speed archive. These data ...

Frank M. Monaldo; Xiaofeng Li; William G. Pichel; Christopher R. Jackson

2014-04-01T23:59:59.000Z

50

Atmospheric Circulation Effects on Wind Speed Variability at Turbine Height  

Science Journals Connector (OSTI)

Mean monthly wind speed at 70 m above ground level is investigated for 11 sites in Minnesota for the period 1995–2003. Wind speeds at these sites show significant spatial and temporal coherence, with prolonged periods of above- and below-normal ...

Katherine Klink

2007-04-01T23:59:59.000Z

51

Variable speed wind turbine generator with zero-sequence filter  

DOE Patents [OSTI]

A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility. The positive sequence current signals are balanced three phase signals and are prevented from entering the utility by the zero sequence filter. The zero sequence current signals have zero phase displacement from each other and are prevented from entering the generator by the star connected stator windings. The zero sequence filter allows the zero sequence current signals to pass through to deliver power to the utility. 14 figs.

Muljadi, E.

1998-08-25T23:59:59.000Z

52

Variable Speed Wind Turbine Generator with Zero-sequence Filter  

DOE Patents [OSTI]

A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility. The positive sequence current signals are balanced three phase signals and are prevented from entering the utility by the zero sequence filter. The zero sequence current signals have zero phase displacement from each other and are prevented from entering the generator by the star connected stator windings. The zero sequence filter allows the zero sequence current signals to pass through to deliver power to the utility.

Muljadi, Eduard (Golden, CO)

1998-08-25T23:59:59.000Z

53

Variable speed wind turbine generator with zero-sequence filter  

DOE Patents [OSTI]

A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility. The positive sequence current signals are balanced three phase signals and are prevented from entering the utility by the zero sequence filter. The zero sequence current signals have zero phase displacement from each other and are prevented from entering the generator by the star connected stator windings. The zero sequence filter allows the zero sequence current signals to pass through to deliver power to the utility.

Muljadi, Eduard (Golden, CO)

1998-01-01T23:59:59.000Z

54

United States Wind Resource Map: Annual Average Wind Speed at...  

Wind Powering America (EERE)

4.0 Source: Wind resource estimates developed by AWS Truepower, LLC for windNavigator . Web: http:www.windnavigator.com | http:www.awstruepower.com. Spatial resolution of wind...

55

Fixed-Speed and Variable-Slip Wind Turbines Providing Spinning Reserves to the Grid: Preprint  

SciTech Connect (OSTI)

As the level of wind penetration increases, wind turbine technology must move from merely generating power from wind to taking a role in supporting the bulk power system. Wind turbines should have the capability to provide inertial response and primary frequency (governor) response so they can support the frequency stability of the grid. To provide governor response, wind turbines should be able to generate less power than the available wind power and hold the rest in reserve, ready to be accessed as needed. This paper explores several ways to control wind turbine output to enable reserve-holding capability. This paper focuses on fixed-speed (also known as Type 1) and variable-slip (also known as Type 2) turbines.

Muljadi, E.; Singh, M.; Gevorgian, V.

2012-11-01T23:59:59.000Z

56

Heuristic correction of wind speed mesoscale models simulations for wind farms prospecting and micrositing  

Science Journals Connector (OSTI)

Abstract The distribution of surface-level wind speeds over a given area is important information that is related to several processes in wind farm prospecting, design and micrositing. This information is often obtained from simulations using mesoscale models that take variables from global models as starting points. Improved outputs from mesoscale models can lead to reduced error compared to real wind speeds in the study area if in situ wind speed measurements are available. In this paper, we present several techniques to correct surface wind speed simulations from mesoscale models using data from measuring stations in wind farms. Specifically, we propose different heuristic corrections of the outputs from mesoscale models by means of surface fitting between the Weibull parameters of the wind speed series (from the mesoscale model) and those from the measuring stations (real wind speed) in the wind farm. The proposed methodology has direct applications in wind farm design, site prospection and micrositing. The good performance of our method is evident in the more accurate surface wind speeds obtained from mesoscale models in two wind farm prospection sites in Spain, where several measuring towers are installed.

B. Saavedra-Moreno; S. Salcedo-Sanz; C. Casanova-Mateo; J.A. Portilla-Figueras; L. Prieto

2014-01-01T23:59:59.000Z

57

Wind Speeds at Heights Crucial for Wind Energy: Measurements and Verification of Forecasts  

Science Journals Connector (OSTI)

Wind speed measurements from one year from meteorological towers and wind turbines at heights between 20 and 250 m for various European sites are analyzed and are compared with operational short-term forecasts of the global ECMWF model. The ...

Susanne Drechsel; Georg J. Mayr; Jakob W. Messner; Reto Stauffer

2012-09-01T23:59:59.000Z

58

A Technique for Deducing Wind Direction from Satellite Microwave Measurements of Wind Speed  

Science Journals Connector (OSTI)

A technique is presented to deduce wind direction from satellite microwave measurements of wind speed information. The technique, based on simple Ekman boundary layer dynamics, makes use of surface pressure fields routinely analyzed at the ...

Tsann-wang Yu

1987-09-01T23:59:59.000Z

59

Evaluation of NSCAT-2 Wind Vectors by Using Statistical Distributions of Wind Speeds and Directions  

Science Journals Connector (OSTI)

In order to validate wind vectors derived from the NASA scatterometer (NSCAT), statistical distributions of wind speeds and directions retrieved by the NSCAT- ... model function have been investigated by comparis...

Naoto Ebuchi

2000-04-01T23:59:59.000Z

60

MODELLING THE VERTICAL WIND SPEED AND TURBULENCE INTENSITY PROFILES AT PROSPECTIVE OFFSHORE WIND FARM SITES  

E-Print Network [OSTI]

MODELLING THE VERTICAL WIND SPEED AND TURBULENCE INTENSITY PROFILES AT PROSPECTIVE OFFSHORE WIND for conditions important for offshore wind energy utilisation are compared and tested: Four models tested with data from the offshore field measurement Rødsand by extrapolating the measured 10 m wind

Heinemann, Detlev

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Beyond 10 Km Range wind-speed measurement with a 1.5 µm all-fiber laser source  

Science Journals Connector (OSTI)

We report the development of a high power single-frequency all-fiber laser for long-range wind speed measurement. The laser source has been integrated in a Lidar architecture and we...

Renard, William; Goular, Didier; Valla, Matthieu; Planchat, Christophe; Augere, Beatrice; Dolfi-Bouteyre, Agnes; Besson, Claudine; Canat, Guillaume

62

File:CV WindSpeed.pdf | Open Energy Information  

Open Energy Info (EERE)

WindSpeed.pdf WindSpeed.pdf Jump to: navigation, search File File history File usage Cape Verde-Map Summarizing Average Wind Speed (m/s) Size of this preview: 776 × 600 pixels. Full resolution ‎(1,650 × 1,275 pixels, file size: 246 KB, MIME type: application/pdf) Description Cape Verde-Map Summarizing Average Wind Speed (m/s) Sources ECOWAS Creation Date 2011/11/14 Coordinates 16.002082°, -24.013197° File history Click on a date/time to view the file as it appeared at that time. Date/Time Thumbnail Dimensions User Comment current 11:43, 14 November 2011 Thumbnail for version as of 11:43, 14 November 2011 1,650 × 1,275 (246 KB) STobin (Talk | contribs) You cannot overwrite this file. Edit this file using an external application (See the setup instructions for more information)

63

United States Wind Resource Map: Annual Average Wind Speed at...  

Wind Powering America (EERE)

5.5 5.0 4.5 4.0 < 4.0 Source: Wind resource estimates developed by AWS Truepower, LLC. Web: http:www.awstruepower.com. Map developed by NREL. Spatial resolution of wind...

64

A comparison between a hydro-wind plant and wind speed forecasting using ARIMA models  

Science Journals Connector (OSTI)

In this paper we will present a comparison between two options for harnessing wind power. We will first analyze the behaviour of a wind farm that goes to the electricity market having previously made a forecast of wind speed while accepting the deviation penalties that these may incur. Second we will study the possibility of the wind farm not going to the market individually but as part of a hydro-wind plant.

2014-01-01T23:59:59.000Z

65

Anemometer Data (Wind Speed, Direction) for Laurel, Nebraska (2001 - 2002)  

Open Energy Info (EERE)

Laurel, Nebraska (2001 - 2002) Laurel, Nebraska (2001 - 2002) Dataset Summary Description Wind data collected from Laurel, Nebraska from a 20-meter anemometer as part of the Western Area Power Administration anemometer loan program. Ten-minute average wind speed and direction is available for 2001 - 2002. The data was originally made available by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs is available http://www.windpoweringamerica.gov/anemometerloans/projects.asp. Source EERE Date Released November 09th, 2010 (4 years ago) Date Updated November 09th, 2010 (4 years ago) Keywords wind wind direction wind speed Data text/csv icon Jun 11, 2001 - Jul 1, 2001 (csv, 144 KiB)

66

The Influence of Wind Speed on Shallow Marine Cumulus Convection  

Science Journals Connector (OSTI)

The role of wind speed on shallow marine cumulus convection is explored using large-eddy simulations and concepts from bulk theory. Focusing on cases characteristic of the trades, the equilibrium trade wind layer is found to be deeper at stronger ...

Louise Nuijens; Bjorn Stevens

2012-01-01T23:59:59.000Z

67

Correcting Wind Speed Measurements for Site Obstructions  

Science Journals Connector (OSTI)

The effects of obstructions on winds measured by the 30 station FLOWS (FAA-Lincoln Laboratory Operational Weather Studies) mesonet and the 6 station FAA LLWAS (Low Level Wind Shear Alčrt System) near Memphis, TN in 1985 are analyzed. The slowing ...

Marilyn M. Wolfson; T. Theodore Fujita

1989-04-01T23:59:59.000Z

68

Low-frequency wind noise correlation in microphone arrays  

Science Journals Connector (OSTI)

A three-axis orthogonal microphone array with ten sensors in each arm has been used to study wind noise in the frequency range from 0.05 to 50 Hz. Simultaneous measurements were made of the three components of the varying wind velocity.Measurements have been made for wind speeds from 4 to 7 m/s at three different sites. The frequency-dependent correlation of the wind noise over a range of wind velocities and atmospheric and environmental conditions in the downwind direction varies as exp (?3.2X) cos (2?X). For the crosswind and vertical directions the correlation decays approximately as exp (?7Y) where X is the separation in wavelengths in the downwind direction and Y is this separation in the crosswind or vertical direction. Over a limited range of wave numbers the power density spectra of the varying wind velocity varied as the wave number to the ? 5 3 power and the pressure spectra as the ? 7 3 power.

F. Douglas Shields

2005-01-01T23:59:59.000Z

69

The Solar Wind Helium Abundance: Variation with Wind Speed and the Solar Cycle  

E-Print Network [OSTI]

The Solar Wind Helium Abundance: Variation with Wind Speed and the Solar Cycle Matthias R. Aellig Alamos National Lab., Los Alamos, NM 87545 Abstract We investigate the helium abundance in the solar wind of 1994 and early 2000 are analyzed. In agreement with similar work for previous solar cycles, we find

Richardson, John

70

Ris-PhD-Report Accounting for the speed shear in wind  

E-Print Network [OSTI]

Risø-PhD-Report Accounting for the speed shear in wind turbine power performance measurement Rozenn for the speed shear in wind turbine power performance measurement Division: Wind Energy Division Abstract the measurement of the wind speed at hub height and the air density to characterise the wind field in front

71

Anemometer Data (Wind Speed, Direction) for Ugashik, AK (2001 - 2002) |  

Open Energy Info (EERE)

0 0 Varnish cache server Browse Upload data GDR 429 Throttled (bot load) Error 429 Throttled (bot load) Throttled (bot load) Guru Meditation: XID: 2142278290 Varnish cache server Anemometer Data (Wind Speed, Direction) for Ugashik, AK (2001 - 2002) Dataset Summary Description Wind data collected from Ugashik Traditional Village in Alaska from an anemometer as part of the Native American anemometer loan program. Monthly mean wind speed is available for 2001 through 2002, as is wind direction and turbulence data. Data is reported from a height of 20 m. The data was originally made available by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs is available http://www.windpoweringamerica.gov/anemometerloans/projects.asp.

72

Anemometer Data (Wind Speed, Direction) for Tanana, AK (2001 - 2002) |  

Open Energy Info (EERE)

40 40 Varnish cache server Anemometer Data (Wind Speed, Direction) for Tanana, AK (2001 - 2002) Dataset Summary Description Wind data collected from Tanana Village in Alaska from an anemometer as part of the Native American anemometer loan program. Monthly mean wind speed is available for 2001 through 2002, as is wind direction and turbulence data. Data is reported from a height of 20 m. The data was originally made available by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs is available http://www.windpoweringamerica.gov/anemometerloans/projects.asp. Source EERE Date Released November 09th, 2010 (4 years ago) Date Updated November 09th, 2010 (4 years ago)

73

Variable speed wind turbine for maximum power capture using adaptive fuzzy integral sliding mode control  

Science Journals Connector (OSTI)

This paper presents a nonlinear control approach to variable speed wind turbine (VSWT) with a wind speed estimator. The dynamics of the wind turbine (WT) is derived from single ... has been considered for exact e...

Saravanakumar Rajendran…

2014-06-01T23:59:59.000Z

74

Variable-Speed Wind Generator System with Maximum Output Power Control  

Science Journals Connector (OSTI)

To achieve maximum output power from wind generator systems, the rotational speed of wind generators should be adjusted in real time according to natural wind speed. This chapter pays attention to an optimum rota...

Yoko Amano

2013-01-01T23:59:59.000Z

75

A wind speed retrieval algorithm by combining 6 and 10 GHz data from Advanced Microwave Scanning Radiometer: Wind speed inside hurricanes  

Science Journals Connector (OSTI)

A wind speed retrieval algorithm was developed using 6 and ... aboard AQUA, for the purpose of retrieving wind speed inside rainstorms, primarily hurricanes and typhoons. ... because the brightness temperature se...

Akira Shibata

2006-06-01T23:59:59.000Z

76

MEASUREMENT OF WIND SPEED FROM COOLING LAKE THERMAL IMAGERY  

SciTech Connect (OSTI)

The Savannah River National Laboratory (SRNL) collected thermal imagery and ground truth data at two commercial power plant cooling lakes to investigate the applicability of laboratory empirical correlations between surface heat flux and wind speed, and statistics derived from thermal imagery. SRNL demonstrated in a previous paper [1] that a linear relationship exists between the standard deviation of image temperature and surface heat flux. In this paper, SRNL will show that the skewness of the temperature distribution derived from cooling lake thermal images correlates with instantaneous wind speed measured at the same location. SRNL collected thermal imagery, surface meteorology and water temperatures from helicopters and boats at the Comanche Peak and H. B. Robinson nuclear power plant cooling lakes. SRNL found that decreasing skewness correlated with increasing wind speed, as was the case for the laboratory experiments. Simple linear and orthogonal regression models both explained about 50% of the variance in the skewness - wind speed plots. A nonlinear (logistic) regression model produced a better fit to the data, apparently because the thermal convection and resulting skewness are related to wind speed in a highly nonlinear way in nearly calm and in windy conditions.

Garrett, A; Robert Kurzeja, R; Eliel Villa-Aleman, E; Cary Tuckfield, C; Malcolm Pendergast, M

2009-01-20T23:59:59.000Z

77

WIND SPEED AND ATMOSPHERIC STABILITY TRENDS FOR SELECTED UNITED STATES SURFACE STATIONS  

SciTech Connect (OSTI)

Recently it has been suggested that global warming and a decrease in mean wind speeds over most land masses are related. Decreases in near surface wind speeds have been reported by previous investigators looking at records with time spans of 15 to 30 years. This study focuses on United States (US) surface stations that have little or no location change since the late 1940s or the 1950s--a time range of up to 58 years. Data were selected from 62 stations (24 of which had not changed location) and separated into ten groups for analysis. The group's annual averages of temperature, wind speed, and percentage of Pasquill-Gifford (PG) stability categories were fitted with linear least squares regression lines. The results showed that the temperatures have increased for eight of the ten groups as expected. Wind speeds have decreased for nine of the ten groups. The mean slope of the wind speed trend lines for stations within the coterminous US was -0.77 m s{sup -1} per century. The percentage frequency of occurrence for the neutral (D) PG stability category decreased, while that for the unstable (B) and the stable (F) categories increased in almost all cases except for the group of stations located in Alaska.

Buckley, R; Allen H. Weber, A

2006-11-01T23:59:59.000Z

78

Optimal control for variable-speed wind generation systems using General Regression Neural Network  

Science Journals Connector (OSTI)

Abstract An induction generator (IG) speed drive with the application of an optimal controller and a proposed General Regression Neural Network (GRNN) controller is introduced in this paper. Grid connected wind energy conversion system (WECS) present interesting control demands, due to the intrinsic nonlinear characteristic of wind mills and electric generators. The GRNN with adaptive ant colony optimization (AACO) torque compensation is feed-forward to increase the robustness of the wind driven induction generator system. An optimal control loop for the wind power system is designed. The optimality of the whole system is defined in relation with the trade-off between the wind energy conversion maximization and the minimization of the induction generator torque variation that is responsible for the frequency fluctuations. This is achieved by using a combined optimization criterion, resulting in a LQ tracking problem with an infinite horizon and a measurable exogenous variable (wind speed). The proposed controller is designed to drive the turbine speed to extract maximum power from the wind and adjust to the power regulation.

Chih-Ming Hong; Fu-Sheng Cheng; Chiung-Hsing Chen

2014-01-01T23:59:59.000Z

79

ARE660 Wind Generator: Low Wind Speed Technology for Small Turbine Development  

SciTech Connect (OSTI)

This project is for the design of a wind turbine that can generate most or all of the net energy required for homes and small businesses in moderately windy areas. The purpose is to expand the current market for residential wind generators by providing cost effective power in a lower wind regime than current technology has made available, as well as reduce noise and improve reliability and safety. Robert W. Preus’ experience designing and/or maintaining residential wind generators of many configurations helped identify the need for an improved experience of safety for the consumer. Current small wind products have unreliable or no method of stopping the wind generator in fault or high wind conditions. Consumers and their neighbors do not want to hear their wind generators. In addition, with current technology, only sites with unusually high wind speeds provide payback times that are acceptable for the on-grid user. Abundant Renewable Energy’s (ARE) basic original concept for the ARE660 was a combination of a stall controlled variable speed small wind generator and automatic fail safe furling for shutdown. The stall control for a small wind generator is not novel, but has not been developed for a variable speed application with a permanent magnet alternator (PMA). The fail safe furling approach for shutdown has not been used to our knowledge.

Robert W. Preus; DOE Project Officer - Keith Bennett

2008-04-23T23:59:59.000Z

80

Manual and Semiautomated Wind Direction Editing for Use in the Generation of Synthetic Aperture Radar Wind Speed Imagery  

Science Journals Connector (OSTI)

Previous studies have demonstrated that satellite synthetic aperture radar (SAR) can be used as an accurate scatterometer, yielding wind speed fields with subkilometer resolution. This wind speed generation is only possible, however, if a ...

George S. Young; Todd D. Sikora; Nathaniel S. Winstead

2007-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Statistics of the Wind-Speed Difference Between Points with Cross-Wind Separation  

Science Journals Connector (OSTI)

This note reports statistics of instantaneous wind-speed differences between pairs of points in the...z...= 2?3 m), but separated by large distances (ranging up to 70 m) along an axis transverse to the direction ...

J. D. Wilson

2013-01-01T23:59:59.000Z

82

Estimated changes in wind speed and wind power density over the western High Plains, 1971–2000  

Science Journals Connector (OSTI)

This manuscript presents the results of research on the temporal patterns in wind speed and wind power density from 1971 to 2000. The ... Mountains in an area which has a proven wind power resource. Policies and ...

J. Scott Greene; Matthew Chatelain; Mark Morrissey…

2012-08-01T23:59:59.000Z

83

Characteristics of wind speed and wind direction in the atmospheric boundary layer on the southern coast of Bulgaria  

Science Journals Connector (OSTI)

The characteristics of wind speed and wind direction in the boundary atmospheric layer measured ... meteorological station. The sodar measurement data on wind parameters at different heights in different months ....

M. A. Novitskii; L. K. Kulizhnikova…

2012-03-01T23:59:59.000Z

84

ON THE ORIGIN OF THE SLOW SPEED SOLAR WIND: HELIUM ABUNDANCE VARIATIONS  

SciTech Connect (OSTI)

The first ionization potential (FIP) effect is the by now well-known enhancement in abundance over photospheric values of Fe and other elements with FIP below about 10 eV observed in the solar corona and slow speed solar wind. In our model, this fractionation is achieved by means of the ponderomotive force, arising as Alfven waves propagate through or reflect from steep density gradients in the solar chromosphere. This is also the region where low FIP elements are ionized, and high FIP elements are largely neutral leading to the fractionation as ions interact with the waves but neutrals do not. Helium, the element with the highest FIP and consequently the last to remain neutral as one moves upward, can be depleted in such models. Here, we investigate this depletion for varying loop lengths and magnetic field strengths. Variations in this depletion arise as the concentration of the ponderomotive force at the top of the chromosphere varies in response to Alfven wave frequency with respect to the resonant frequency of the overlying coronal loop, the magnetic field, and possibly also the loop length. We find that stronger depletions of He are obtained for weaker magnetic field, at frequencies close to or just above the loop resonance. These results may have relevance to observed variations of the slow wind solar He abundance with wind speed, with slower slow speed solar wind having a stronger depletion of He.

Rakowski, Cara E.; Laming, J. Martin [Space Science Division, Naval Research Laboratory Code 7674L, Washington, DC 20375 (United States)

2012-07-20T23:59:59.000Z

85

Ris-R-Report Comparison of NWP wind speeds and  

E-Print Network [OSTI]

for nuclear power plants, and for Risø, the site of the Danish nuclear research reactors now being Risø 5 German nuclear power plant sites 9 Brunsbüttel 9 Brokdorf 12 Krümmel 15 Obrigheim 18) of wind speed and direction has been compared to measurements for seven German sites for nuclear power

86

Short term wind speed estimation in Saudi Arabia  

Science Journals Connector (OSTI)

Abstract In this paper, three methods are used for the prediction of wind speed, 12 h ahead, based on 72 h previous wind speed values at three locations viz. Rawdat Bin Habbas (inland north), Juaymah (east coast), and Dhulom (inland western region) in Saudi Arabia. These methods are Particle Swarm Optimization (PSO), Abductory Induction Mechanism (AIM), and the Persistence (PER) model. The available data at each site was divided into three consecutive groups. The first 50% was used for training, the second 25% for validation, and the remaining 25% for testing. The validation data set was used to select the network architecture and other user defined parameters. The testing data was used only to assess the performance of the networks on future unseen data that has not been used for training or model selection. For each of the three methods, each of 12 networks was trained to produce the wind speed at one of the next 12 h. Relatively, Close agreements were found between the predicted and measured hourly mean wind speed for all three locations with coefficient of correlation R2 values between 81.7% and 98.0% for PSO, between 79.8% and 98.5% for AIM and between 59.5% and 88.4% for persistence model. Both PSO and AIM methods underestimated WS values during most hours with an average value of 0.036 m/s and 0.02 m/s, respectively. However, persistence model overestimated the WS by an average value of 0.51 m/s. It is shown that the two developed models outperformed the persistence model on predicting wind speed 12 h ahead of time with slight advantage to the PSO method.

Mohamed Ahmed Mohandes; Shafiqur Rehman

2014-01-01T23:59:59.000Z

87

Hi-Q Rotor - Low Wind Speed Technology  

SciTech Connect (OSTI)

The project objective was to optimize the performance of the Hi-Q Rotor. Early research funded by the California Energy Commission indicated the design might be advantageous over state-of-the-art turbines for collecting wind energy in low wind conditions. The Hi-Q Rotor is a new kind of rotor targeted for harvesting wind in Class 2, 3, and 4 sites, and has application in areas that are closer to cities, or 'load centers.' An advantage of the Hi-Q Rotor is that the rotor has non-conventional blade tips, producing less turbulence, and is quieter than standard wind turbine blades which is critical to the low-wind populated urban sites. Unlike state-of-the-art propeller type blades, the Hi-Q Rotor has six blades connected by end caps. In this phase of the research funded by DOE's Inventions and Innovation Program, the goal was to improve the current design by building a series of theoretical and numeric models, and composite prototypes to determine a best of class device. Development of the rotor was performed by aeronautical engineering and design firm, DARcorporation. From this investigation, an optimized design was determined and an 8-foot diameter, full-scale rotor was built and mounted using a Bergey LX-1 generator and furling system which were adapted to support the rotor. The Hi-Q Rotor was then tested side-by-side against the state-of-the-art Bergey XL-1 at the Alternative Energy Institute's Wind Test Center at West Texas State University for six weeks, and real time measurements of power generated were collected and compared. Early wind tunnel testing showed that the cut-in-speed of the Hi-Q rotor is much lower than a conventional tested HAWT enabling the Hi-Q Wind Turbine to begin collecting energy before a conventional HAWT has started spinning. Also, torque at low wind speeds for the Hi-Q Wind Turbine is higher than the tested conventional HAWT and enabled the wind turbine to generate power at lower wind speeds. Based on the data collected, the results of our first full-scale prototype wind turbine proved that higher energy can be captured at lower wind speeds with the new Hi-Q Rotor. The Hi-Q Rotor is almost 15% more productive than the Bergey from 6 m/s to 8 m/s, making it ideal in Class 3, 4, and 5 wind sites and has application in the critical and heretofore untapped areas that are closer to cities, 'load centers,' and may even be used directly in urban areas. The additional advantage of the Hi-Q Rotor's non-conventional blade tips, which eliminates most air turbulence, is noise reduction which makes it doubly ideal for populated urban areas. Hi-Q Products recommends one final stage of development to take the Hi-Q Rotor through Technology Readiness Levels 8-9. During this stage of development, the rotor will be redesigned to further increase efficiency, match the rotor to a more suitable generator, and lower the cost of manufacturing by redesigning the structure to allow for production in larger quantities at lower cost. Before taking the rotor to market and commercialization, it is necessary to further optimize the performance by finding a better generator and autofurling system, ones more suitable for lower wind speeds and rpms should be used in all future testing. The potential impact of this fully developed technology will be the expansion and proliferation of energy renewal into the heretofore untapped Class 2, 3, 4, and 5 Wind Sites, or the large underutilized sites where the wind speed is broken by physical features such as mountains, buildings, and trees. Market estimates by 2011, if low wind speed technology can be developed are well above: 13 million homes, 675,000 commercial buildings, 250,000 public facilities. Estimated commercial exploitation of the Hi-Q Rotor show potential increase in U.S. energy gained through the clean, renewable wind energy found in low and very low wind speed sites. This new energy source would greatly impact greenhouse emissions as well as the public sector's growing energy demands.

Todd E. Mills; Judy Tatum

2010-01-11T23:59:59.000Z

88

Wind Speed Retrieval Based on Sea Surface Roughness Measurements from Spaceborne Microwave Radiometers  

Science Journals Connector (OSTI)

Wind speed is the main factor responsible for the increase in ocean thermal emission because sea surface emissivity strongly depends on surface roughness. An alternative approach to estimate the surface wind speed (SWS) as a function of surface ...

Sungwook Hong; Inchul Shin

2013-02-01T23:59:59.000Z

89

Comparison of Two ARMA-GARCH Approaches for Forecasting the Mean and Volatility of Wind Speed  

Science Journals Connector (OSTI)

In this study, we develop two ARMA-GARCH models for predicting the mean and volatility of wind speed. The first model employs the standalone ARMA-GARCH model for modeling the mean wind speed and the variance simu...

Ergin Erdem; Jing Shi; Ying She

2014-01-01T23:59:59.000Z

90

Development of All-fiber Coherent Doppler Lidar to Measure Atmosphere Wind Speed  

Science Journals Connector (OSTI)

An all-fiber pulsed coherent Doppler lidar is developed to measure wind profiles. The maximum horizontal and vertical range for wind speed is 4.2km and 2km with speed accuracy of...

Liu, Jiqiao; Chen, Weibiao; Zhu, Xiaopeng

91

Measurements of Wind Speed, Direction, and Vertical Profiles in an Evergreen Forest in Central Cambodia  

Science Journals Connector (OSTI)

The wind characteristics of speed, direction, and vertical profile were studied ... Thom Province, Cambodia. Three seasonal patterns of wind speeds and directions were identified. The first occurred ... , as well...

Koji Tamai; Akira Shimizu…

2007-01-01T23:59:59.000Z

92

United States- Land Based and Offshore Annual Average Wind Speed at 100 Meters  

Broader source: Energy.gov [DOE]

Full-size, high resolution version of the 100-meter land-based and offshore wind speed resource map.

93

Applying micro scales of horizontal axis wind turbines for operation in low wind speed regions  

Science Journals Connector (OSTI)

Abstract Utilizing the micro scales of wind turbines could noticeably supply the demand for the electricity in low wind speed regions. Aerodynamic design and optimization of the blade, as a main part of a wind turbine, were addressed in the study. Three micro scales of horizontal axis wind turbines with output power of 0.5, 0.75 and 1 kW were considered and the geometric optimization of the blades in terms of the two involved parameters, chord and twist, was undertaken. In order to improve the performance of the turbines at low wind speeds, starting time was included in an objective function in addition to the output power – the main and desirable goal of the wind turbine blade design. A purpose-built genetic algorithm was employed to maximize both the output power and the starting performance which were calculated by the blade-element momentum theory. The results emphasize that the larger values of the chord and twist at the root part of the blades are indispensable for the better performance when the wind speed is low. However, the noticeable value of the generator resistive torque could largely delay the starting of the micro-turbines especially for the considered smaller size, 0.5 kW, where the starting aerodynamic torque could not overcome the generator resistive torque. For that size, an increase in the number of blades improved both the starting performance and also output power.

Abolfazl Pourrajabian; Reza Ebrahimi; Masoud Mirzaei

2014-01-01T23:59:59.000Z

94

Simultaneous Retreival of Surface Wind Speed and Rain Rate using Radar and Radiometer Measurements  

E-Print Network [OSTI]

to simultaneously retrieve the vertical profile of precipitation and the near-surface wind speed. ResultsSimultaneous Retreival of Surface Wind Speed and Rain Rate using Radar and Radiometer Measurements simultaneously estimates the over ocean near-surface wind speed and rain rate profile using data from a 10.7 GHz

Ruf, Christopher

95

A Robust STATCOM Control to Augment LVRT capability of Fixed Speed Wind Turbines  

E-Print Network [OSTI]

A Robust STATCOM Control to Augment LVRT capability of Fixed Speed Wind Turbines M. J. Hossain, H Compensator (STATCOM) to enhance the Low-Voltage Ride- Through (LVRT) capability of fixed-speed wind turbines cost and maintenance due to rugged brushless construction. Constant speed wind turbines equipped

Pota, Himanshu Roy

96

Ris-R-Report Analysis of vertical wind direction and speed  

E-Print Network [OSTI]

Risø-R-Report Analysis of vertical wind direction and speed gradients for data from the met. mast Cariou, Rozenn Wagner, Julia Gottschall Title: Analysis of vertical wind direction and speed gradients. Finally, the direction shear was analysed as function of wind speed and compared to the corresponding

97

Wind speed influence on phytoplankton bloom dynamics in the Southern Ocean Marginal Ice Zone  

E-Print Network [OSTI]

Niebauer, H. J. (1982), Wind and melt driven circulation inJ. K. Moore (2007), Wind speed influence on phytoplanktonby the NASA Ocean Vector Winds Science Team. Data are

Fitch, Dillon T; Moore, J. Keith

2007-01-01T23:59:59.000Z

98

Observed and CAM3 GCM Sea Surface Wind Speed Distributions: Characterization, Comparison, and Bias Reduction  

E-Print Network [OSTI]

data, all from 2000 to 2005. Wind speed mean, 90th percentile, standard deviation, and Weibull shape and energy fluxes depend nonlinearly on wind speed magnitude, are sensitive to the tails of the wind statistics, particularly in the Southern Hemisphere storm track, consistent with the hypothesis. These wind

Zender, Charles

99

Long-distance seed dispersal by wind: disentangling the effects of species traits, vegetation types, vertical turbulence and wind speed  

Science Journals Connector (OSTI)

Long-distance dispersal (LDD) of plant seeds by wind is affected by functional traits of the ... , as well as by the meteorological parameters wind speed and vertical turbulence. The relative importance of ... fo...

Felix Heydel; Sarah Cunze; Markus Bernhardt-Römermann…

2014-07-01T23:59:59.000Z

100

MASON LAB B-7 WIND TUNNEL OPERATING INSTRUCTIONS Our wind tunnel is a low speed tunnel with a test section 15"x24" It has a digital controller  

E-Print Network [OSTI]

MASON LAB B-7 WIND TUNNEL OPERATING INSTRUCTIONS Our wind tunnel is a low speed tunnel with a test approximate wind tunnel speed in m/s (meters/second) and tunnel speed will go to that set point speed measure lift (~25 N) and drag (~8 N) PRECAUTIONS: ALL OBJECTS MUST BE SECURED BEFORE STARTING WIND TUNNEL

Haller, Gary L.

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Wind Turbine Pitch Angle Controllers for Grid Frequency Stabilisation  

E-Print Network [OSTI]

Laboratory Wind Energy Department P.O. Box 49 DK-4000 Roskilde, Denmark clemens.jauch@risoe.dk Abstract in Norway [4]. For the purpose of this research work the power system model has been extended with a windWind Turbine Pitch Angle Controllers for Grid Frequency Stabilisation Clemens Jauch Risø National

102

Pitch-Controlled Variable-Speed Wind Turbine Generation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Pitch-Controlled Variable-Speed Pitch-Controlled Variable-Speed Wind Turbine Generation February 2000 * NREL/CP-500-27143 E. Muljadi and C.P. Butterfield Presented at the 1999 IEEE Industry Applications Society Annual Meeting Phoenix, Arizona October 3-7, 1999 National Renewable Energy Laboratory 1617 Cole Boulevard Golden, Colorado 80401-3393 NREL is a U.S. Department of Energy Laboratory Operated by Midwest Research Institute * * * * Battelle * * * * Bechtel Contract No. DE-AC36-99-GO10337 NOTICE The submitted manuscript has been offered by an employee of the Midwest Research Institute (MRI), a contractor of the US Government under Contract No. DE-AC36-99GO10337. Accordingly, the US Government and MRI retain a nonexclusive royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for US Government purposes.

103

Tracking an Aerodynamic Model in a Wind Tunnel with a Stereo High-speed Imaging System  

E-Print Network [OSTI]

Tracking an Aerodynamic Model in a Wind Tunnel with a Stereo High-speed Imaging System Lichuan Gui in wind tunnel tests with a stereo high-speed imaging system. The imaging system includes two high angle, pitch angle and yaw angle of the aerodynamic model in the wind tunnel. Tests and simulations were

Gui, Lichuan

104

Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems  

E-Print Network [OSTI]

Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems B. Beltran, T. Ahmed power generation in variable speed wind energy conversion systems (VS-WECS). These systems have two variations. Index Terms--Wind energy conversion system, power generation control, sliding mode control

Boyer, Edmond

105

Letters: Neural network based hybrid computing model for wind speed prediction  

Science Journals Connector (OSTI)

This paper proposes a Neural Network based hybrid computing model for wind speed prediction in renewable energy systems. Wind energy is one of the renewable energy sources which lower the cost of electricity production. Due to the fluctuation and nonlinearity ... Keywords: Hybrid Model, Multilayer Perceptron, Neural Networks, Self Organizing Maps, Wind Speed Prediction

K. Gnana Sheela; S. N. Deepa

2013-12-01T23:59:59.000Z

106

Wind: wind speed and wind power density GIS data at 50m above ground and  

Open Energy Info (EERE)

Kenya from RisoeDTU Kenya from RisoeDTU Dataset Summary Description (Abstract): These data are results from the KAMM/WASP studies for Kenya. The KAMM/WAsP methodology uses a set of wind classes to represent wind conditions for the mapped region. A mesoscale simulation for each wind class, using KAMM (Karlsruhe Mesoscale Model), is performed and statistics performed on the model output. The results are a summary of the simulated wind climate, and ii. a wind atlas, a summary of the wind climate standardized to flat, uniform roughness terrain. (Purpose): The product is intended to be used to estimate the wind resource potential in the country including the the spatial variability. This map covers regions where long term measurements are not available. In a sense this is the point of the

107

Wind: wind speed and wind power density GIS data at 50m above ground and  

Open Energy Info (EERE)

Bangladesh from RisoeDTU Bangladesh from RisoeDTU Dataset Summary Description (Abstract): These data are results from the KAMM/WASP studies for Bangladesh. Version 2 is an updated version of the earlier release and includes an adjustment to Weibull A and k to bring the Atlas values into better agreement with observations. See supplemental information.The KAMM/WAsP methodology uses a set of wind classes to represent wind conditions for the mapped region. A mesoscale simulation for each wind class, using KAMM (Karlsruhe Mesoscale Model), is performed and statistics performed on the model output. The result is i. a wind resource map, a summary of the simulated wind climate, and ii. a wind atlas, a summary of the wind climate standardized to flat, uniform roughness terrain. (Purpose): The product is intended to be used to

108

File:QuikSCAT - Annual Wind Speed at 10 m.pdf | Open Energy Information  

Open Energy Info (EERE)

QuikSCAT - Annual Wind Speed at 10 m.pdf QuikSCAT - Annual Wind Speed at 10 m.pdf Jump to: navigation, search File File history File usage QuikSCAT - Annual Wind Speed at 10 m Size of this preview: 463 × 599 pixels. Other resolution: 464 × 600 pixels. Full resolution ‎(1,275 × 1,650 pixels, file size: 1.19 MB, MIME type: application/pdf) Title Annual Wind Speed at 10 m Description QuikSCAT - Annual Wind Speed at 10 m Sources NREL, National Aeronautics and Space Administration Extent International Coordinates 0°, 0° Scatterometer measurements of the state of the ocean surface are used to estimate 10-m ocean winds in the QuikSCAT satellite data set. The QuikSCAT data are produced by Remote Sensing Systems and sponsored by the U.S. National Aeronautics and Space Administration Ocean Vector Winds Science

109

Low Wind Speed Turbine Development Project Report: November 4, 2002 - December 31, 2006  

SciTech Connect (OSTI)

This report summarizes work conducted by Clipper Windpower under the DOE Low Wind Speed Turbine project. The objective of this project was to produce a wind turbine that can lower the cost of energy.

Mikhail, A.

2009-01-01T23:59:59.000Z

110

An improved wind speed algorithm for “Jason-1” altimeter under tropical cyclone conditions  

Science Journals Connector (OSTI)

Rain effect and lack of in situ validation data are two main causes of tropical cyclone wind retrieval errors. The National Oceanic and Atmospheric ... (NRCS); Hurricane Research Division (HRD) wind speed, which ...

Bangyong Qin; Xuan Zhou; Honglei Zhang; Xiaofeng Yang; Rong Lu…

2014-07-01T23:59:59.000Z

111

A WRF Ensemble for Improved Wind Speed Forecasts at Turbine Height  

Science Journals Connector (OSTI)

The Weather Research and Forecasting Model (WRF) with 10-km horizontal grid spacing was used to explore improvements in wind speed forecasts at a typical wind turbine hub height (80 m). An ensemble consisting of WRF model simulations with ...

Adam J. Deppe; William A. Gallus Jr.; Eugene S. Takle

2013-02-01T23:59:59.000Z

112

An Isofactorial Change-of-Scale Model for the Wind Speed Probability Density Function  

Science Journals Connector (OSTI)

The wind speed probability density function (PDF) is used in a variety of applications in meteorology, oceanography, and climatology usually as a dataset comparison tool of a function of a quantity such as momentum flux or wind power density. The ...

Mark L. Morrissey; Angie Albers; J. Scott Greene; Susan Postawko

2010-02-01T23:59:59.000Z

113

The effect of wind speed fluctuations on the performance of a wind-powered membrane system for brackish water desalination   

E-Print Network [OSTI]

A wind-powered reverse osmosis membrane (wind-membrane) system without energy storage was tested using synthetic brackish water (2750 and 5500 mg/L NaCl) over a range of simulated wind speeds under both steady-state and ...

Park, Gavin L.; Schäfer, Andrea; Richards, Bryce S.

2011-01-01T23:59:59.000Z

114

A first order geometric auto regressive process for boundary layer wind speed simulation  

Science Journals Connector (OSTI)

Under certain conditions the first order geometric auto regressive (AR) process has statistical properties similar to atmospheric boundary layer wind speed. In this contribution, we investigate ... this stochas...

T. Laubrich; H. Kantz

2009-08-01T23:59:59.000Z

115

About First Order Geometric Auto Regressive Processes for Boundary Layer Wind Speed Simulation  

Science Journals Connector (OSTI)

Under certain conditions the first order geometric auto regressive process has statistical properties similar to atmospheric boundary layer wind speed. In this contribution, we investigate ... this stochastic pro...

Thomas Laubrich; Holger Kantz

2010-01-01T23:59:59.000Z

116

E-Print Network 3.0 - accurate wind speed Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: anywhere in the world. As the annual mean wind speed goes up, the cost per energy unit decreases, hence... measurements are obtained at one point. Satellite derived...

117

Master's thesis: "Wind speed measurements in an offshore wind farm by remote sensing: Comparison of radar satellite TerraSAR-X and ground-based  

E-Print Network [OSTI]

Master's thesis: "Wind speed measurements in an offshore wind farm by remote sensing: Comparison of the Offshore wind farm alpha ventus with 12 wind turbines, substation and met mast Fino1. Southerly winds cause (wake) caused by wind farms and especially for the interaction of large offshore wind farms, which can

Peinke, Joachim

118

Wind: wind speed and wind power density GIS data at 50m above ground and  

Open Energy Info (EERE)

Ethiopia from RisoeDTU Ethiopia from RisoeDTU Dataset Summary Description (Abstract): These data are results from the KAMM/WASP studies for Ethiopia. The KAMM/WAsP methodology uses a set of wind classes to represent wind conditions for the mapped region. A mesoscale simulation for each wind class, using KAMM (Karlsruhe Mesoscale Model), is performed and statistics performed on the model output. The results are a summary of the simulated wind climate, and ii.a wind atlas, a summary of the wind climate standardized to flat, uniform roughness terrain. (Purpose): The product is intended to be used to estimate the wind resource potential in the country including the spatial variability. This map covers regions where long term measurements are not available. In a sense this is the point of the mapping exercise, but it also means that verification of results has not been as complete would be ideal. There is some concern that the results may underestimate the resource. However, new measurement data is coming and revisions to the map may be made if necessary as verification is carried out.

119

Can Satellite Sampling of Offshore Wind Speeds Realistically Represent Wind Speed Distributions? Part II: Quantifying Uncertainties Associated with Distribution Fitting Methods  

Science Journals Connector (OSTI)

Remote sensing tools represent an attractive proposition for measuring wind speeds over the oceans because, in principle, they also offer a mechanism for determining the spatial variability of flow. Presented here is the continuation of research ...

S. C. Pryor; M. Nielsen; R. J. Barthelmie; J. Mann

2004-05-01T23:59:59.000Z

120

A WRF Ensemble for Improved Wind Speed Forecasts at Turbine Height ADAM J. DEPPE AND WILLIAM A. GALLUS JR.  

E-Print Network [OSTI]

A WRF Ensemble for Improved Wind Speed Forecasts at Turbine Height ADAM J. DEPPE AND WILLIAM A in wind speed forecasts at a typical wind turbine hub height (80 m). An ensemble consisting of WRF model ensemble members for forecasting wind speed. A second configuration using three random perturbations

McCalley, James D.

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Effects of Rain Rate and Wind Magnitude on SeaWinds Scatterometer Wind Speed Errors  

Science Journals Connector (OSTI)

Rain within the footprint of the SeaWinds scatterometer on the QuikSCAT satellite causes more significant errors than existed with its predecessor, the NASA scatterometer (NSCAT) on Advanced Earth Observing Satellite-I (ADEOS-I). Empirical ...

David E. Weissman; Mark A. Bourassa; Jeffrey Tongue

2002-05-01T23:59:59.000Z

122

Wind: wind speed and wind power density GIS data at 50m above ground and  

Open Energy Info (EERE)

Nepal from RisoeDTU Nepal from RisoeDTU Dataset Summary Description (Abstract): These data are results from the KAMM/WASP studies for Nepal. The KAMM/WAsP methodology uses a set of windclasses to represent wind conditions for the mapped region. A mesoscale simulation for each wind class, using KAMM (Karlsruhe Mesoscale Model), is performed and statistics performed on the model output. The results are a summary of the simulated wind climate, and a wind atlas, a summary of the wind climate standardized to flat, uniform roughness terrain. (Purpose): The product is intended to be used to estimate the wind resource potential in the country including the the spatial variability. This map covers regions where long term measurements are not available. In a sense this is the point of the mapping exercise, but it also means that verification of results has not been as complete would be ideal. There is some concern that the results may underestimate the resource. However, new measurement data is coming and revisions to the map may be made if necessary as verification is carried out.

123

The effect of high penetration of wind power on primary frequency control of power systems.  

E-Print Network [OSTI]

??In this work, a power system with wind power units and hydro power units are considered. The hydro power unit and variable speed wind turbine… (more)

Motamed, Bardia

2013-01-01T23:59:59.000Z

124

Seasonal Forecasting of Extreme Wind and Precipitation Frequencies in Europe  

E-Print Network [OSTI]

Seasonal Forecasting of Extreme Wind and Precipitation Frequencies in Europe Matthew J. Swann;Abstract Flood and wind damage to property and livelihoods resulting from extreme precipitation events variability of these extreme events can be closely related to the large-scale atmospheric circulation

Feigon, Brooke

125

Robust STATCOM control for the stabilisation of fixed-speed wind turbines during low voltages  

E-Print Network [OSTI]

and rotor- speed instability and more so if the wind turbine is connected to a weak grid. To prevent is still being produced by squirrel-cage induction generators (SCIGs) which are directly connected to the grid and operate at an almost fixed-speed [3]. They are advantageous as wind generators for their low

Pota, Himanshu Roy

126

Numerical simulation of aerodynamic derivatives and critical wind speed for long-span bridges based on simplified steady wind field  

Science Journals Connector (OSTI)

Combining the computational fluid dynamics-based numerical simulation with the forced vibration technique for extraction ... calculating the aerodynamic derivatives and the critical flutter wind speed for long-sp...

Dabo Xin Ph.D. Student ???; Jinping Ou ???

2007-06-01T23:59:59.000Z

127

Wind Conditions in a Fjordlike Bay and Predictions of Wind Speed Using Neighboring Stations Employing Neural Network Models  

Science Journals Connector (OSTI)

This paper evaluates the applicability of neural networks for estimating wind speeds at various target locations using neighboring reference locations along the south coast of Newfoundland, Canada. The stations were chosen to cover a variety of ...

Jens J. Currie; Pierre J. Goulet; Andry W. Ratsimandresy

2014-06-01T23:59:59.000Z

128

Ris0-M-2829 2 Extreme Values ofWind Speeds  

E-Print Network [OSTI]

Ris0-M-2829 2 Extreme Values ofWind Speeds overthe Great Belt Region N.O. Jensen and B. Nielsen Ris events 9 4 Extrapolation to the 50-year storm 11 5 Discussion of the 50-year wind 15 6 Crosswind extremes for extreme values of wind speeds. The data material was obtained from a 70-m mast on a small island, Sprog0

129

Instrument Design Simulations for Synthetic Aperture Microwave Radiometric Imaging of Wind Speed and  

E-Print Network [OSTI]

Instrument Design Simulations for Synthetic Aperture Microwave Radiometric Imaging of Wind Speed, US Abstract -- The measurement of peak winds in hurricanes is critical to forecasting intensity in radiative transfer modeling for hurricane force winds and large incidence angles are required for HIRad

Ruf, Christopher

130

Modelling and Analysis of Variable Speed Wind Turbines with Induction Generator during Grid  

E-Print Network [OSTI]

Modelling and Analysis of Variable Speed Wind Turbines with Induction Generator during Grid Fault Wind Turbines with Induction Generator during Grid Fault by Sigrid M. Bolik Institute of Energy turbine technology has undergone rapid developments. Growth in size and the optimization of wind turbines

Hansen, René Rydhof

131

Individual Pitch Control for Mitigation of Power Fluctuation of Variable Speed Wind Turbines  

E-Print Network [OSTI]

Individual Pitch Control for Mitigation of Power Fluctuation of Variable Speed Wind Turbines, China mcheng@seu.edu.cn Abstract-- Grid connected wind turbines are the sources of power fluctuations presents an individual pitch control (IPC) strategy to mitigate the wind turbine power fluctuation at both

Hu, Weihao

132

SCALAR WIND SPEED AND DIRECTION TROPICAL CYCLONE RETRIEVALS FOR CONICAL SCANNING SCATTEROMETERS  

E-Print Network [OSTI]

SCALAR WIND SPEED AND DIRECTION TROPICAL CYCLONE RETRIEVALS FOR CONICAL SCANNING SCATTEROMETERS--Scatterometer measurements of ocean vector winds (OVW) are significantly degraded in the presence of the precipitation, especially in tropical cyclones. This paper presents a new ocean hurricane/typhoon wind vector retrieval

Hennon, Christopher C.

133

EVALUATION OF MODELS FOR THE VERTICAL EXTRAPOLATION OF WIND SPEED MEASUREMENTS AT OFFSHORE SITES  

E-Print Network [OSTI]

EVALUATION OF MODELS FOR THE VERTICAL EXTRAPOLATION OF WIND SPEED MEASUREMENTS AT OFFSHORE SITES important for offshore wind energy utilisation are discussed and tested: Four models for the surface tested with data from the offshore field measurement Rødsand by extrapolating the measured 10 m wind

Heinemann, Detlev

134

The Impacts of Wind Speed Trends and Long-term Variability in Relation to Hydroelectric  

E-Print Network [OSTI]

The Impacts of Wind Speed Trends and Long- term Variability in Relation to Hydroelectric Reservoir and Long-term Variability in Relation to Hydroelectric Reservoir Inflows on Wind Power in the Pacific through diversification. In hydroelectric dominated systems, like the PNW, the benefits of wind power can

Kohfeld, Karen

135

An aero-elastic flutter based electromagnetic energy harvester with wind speed augmenting funnel  

E-Print Network [OSTI]

An aero-elastic flutter based electromagnetic energy harvester with wind speed augmenting funnel been used to convert wind flow energy into mechanical vibration, which is then transformed-scale renewable energy generating systems such as wind turbines, thermal generators, and solar panels, energy

Stanford University

136

An Examination of Tropical and Extratropical Gust Factors and the Associated Wind Speed Histograms  

Science Journals Connector (OSTI)

A gust factor, defined as the ratio between a peak wind gust and mean wind speed over a period of time, can be used along with other statistics to examine the structure of the wind. Gust factors are heavily dependent on upstream terrain ...

B. M. Paulsen; J. L. Schroeder

2005-02-01T23:59:59.000Z

137

Soft computing based optimum parameter design of PID controller in rotor speed control of wind turbines  

Science Journals Connector (OSTI)

Sensitivity and robustness is the primary issue while designing the controller for large non-linear systems such as offshore wind turbines. The main goal of this study is a novel soft computing based approach in controlling the rotor speed of wind turbine. ... Keywords: bacteria foraging optimization algorithm, optimization, particle swarm optimization, proportional-integral-derivative controller, wind turbines

R. Manikandan; Nilanjan Saha

2011-12-01T23:59:59.000Z

138

Classification of Vertical Wind Speed Profiles Observed Above a Sloping Forest at Nighttime Using the Bulk Richardson Number  

Science Journals Connector (OSTI)

Wind speed profiles above a forest canopy relate to ... atmosphere. Many studies have reported that vertical wind speed profiles above a relatively flat forest can ... be classified by a stability index developed...

Hikaru Komatsu; Norifumi Hotta; Koichiro Kuraji…

2005-05-01T23:59:59.000Z

139

First and second order semi-Markov chains for wind speed modeling  

E-Print Network [OSTI]

The increasing interest in renewable energy, particularly in wind, has given rise to the necessity of accurate models for the generation of good synthetic wind speed data. Markov chains are often used with this purpose but better models are needed to reproduce the statistical properties of wind speed data. We downloaded a database, freely available from the web, in which are included wind speed data taken from L.S.I. -Lastem station (Italy) and sampled every 10 minutes. With the aim of reproducing the statistical properties of this data we propose the use of three semi-Markov models. We generate synthetic time series for wind speed by means of Monte Carlo simulations. The time lagged autocorrelation is then used to compare statistical properties of the proposed models with those of real data and also with a synthetic time series generated though a simple Markov chain.

D'Amico, Guglielmo; Prattico, Flavio

2012-01-01T23:59:59.000Z

140

Integral variable structure current control of DFIG-based wind turbines near cut-in speed  

Science Journals Connector (OSTI)

Based on the grid voltage orientated vector control technique, a novel integral variable structure controller for current control of variable speed doubly fed induction generator (DFIG) wind turbines near cut-in wind speed is proposed. The proposed current controller can not only ensure generators' safe cut-in switches to the grid, but also maximum energy capture after switch motion without any regulations. By these, simulations of a 1.5 MW DFIG-based wind turbine near cut-in wind speed are separately conducted under integral variable structure control (IVSC) and PI control. The results show that IVSC strategy, which gives better dynamic response, less static error, smaller controller output dithering, stronger global robustness against generator parameters uncertainty and the grid voltage fluctuation, as well as needless controller regulation after cutting-in the grid, obviously preponderates over traditional PI control for DFIG-based wind turbines near cut-in speed.

Changliang Xia; Huimin Wang; Zhanfeng Song

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Dependency of U.S. Hurricane Economic Loss on Maximum Wind Speed and Storm Size  

E-Print Network [OSTI]

Many empirical hurricane economic loss models consider only wind speed and neglect storm size. These models may be inadequate in accurately predicting the losses of super-sized storms, such as Hurricane Sandy in 2012. In this study, we examined the dependencies of normalized U.S. hurricane loss on both wind speed and storm size for 73 tropical cyclones that made landfall in the U.S. from 1988 to 2012. A multi-variate least squares regression is used to construct a hurricane loss model using both wind speed and size as predictors. Using maximum wind speed and size together captures more variance of losses than using wind speed or size alone. It is found that normalized hurricane loss (L) approximately follows a power law relation with maximum wind speed (Vmax) and size (R). Assuming L=10^c Vmax^a R^b, c being a scaling factor, the coefficients, a and b, generally range between 4-12 and 2-4, respectively. Both a and b tend to increase with stronger wind speed. For large losses, a weighted regression model, with...

Zhai, Alice R

2014-01-01T23:59:59.000Z

142

A new hybrid model optimized by an intelligent optimization algorithm for wind speed forecasting  

Science Journals Connector (OSTI)

Abstract Forecasting the wind speed is indispensable in wind-related engineering studies and is important in the management of wind farms. As a technique essential for the future of clean energy systems, reducing the forecasting errors related to wind speed has always been an important research subject. In this paper, an optimized hybrid method based on the Autoregressive Integrated Moving Average (ARIMA) and Kalman filter is proposed to forecast the daily mean wind speed in western China. This approach employs Particle Swarm Optimization (PSO) as an intelligent optimization algorithm to optimize the parameters of the ARIMA model, which develops a hybrid model that is best adapted to the data set, increasing the fitting accuracy and avoiding over-fitting. The proposed method is subsequently examined on the wind farms of western China, where the proposed hybrid model is shown to perform effectively and steadily.

Zhongyue Su; Jianzhou Wang; Haiyan Lu; Ge Zhao

2014-01-01T23:59:59.000Z

143

Luminescence intensity in coral skeletons from Mona Island in the Caribbean Sea and its link to precipitation and wind speed  

Science Journals Connector (OSTI)

...and its link to precipitation and wind speed Johan Nyberg 1 Present address...proxy of precipitation and (trade) wind speed. In order to find wavelength pairs...records of regional precipitation and wind speed. In the coral skeleton as well...

2002-01-01T23:59:59.000Z

144

Long-term-average, solar cycle, and seasonal response of magnetospheric energetic electrons to the solar wind speed  

E-Print Network [OSTI]

to the solar wind speed D. Vassiliadis,1 A. J. Klimas,2 S. G. Kanekal,3 D. N. Baker,3 and R. S. Weigel4. [1] Among the interplanetary activity parameters the solar wind speed is the one best correlated, and seasonal response of magnetospheric energetic electrons to the solar wind speed, J. Geophys. Res., 107(A11

Vassiliadis, Dimitrios

145

Evidence of a Threshold Wind Speed in Tower-mounted Scatterometer Data David W. Draper and David G. Long  

E-Print Network [OSTI]

Evidence of a Threshold Wind Speed in Tower-mounted Scatterometer Data David W. Draper and David G ) in scatterom- eter measurements over water is theorized to go to zero below a threshold wind speed due. Evidence of the threshold wind speed and a hysteresis effect have been observed in airship and wave tank

Long, David G.

146

Evidence of trends in near-surface wind speeds over the Baltic S.C. Pryor1,2  

E-Print Network [OSTI]

1 Evidence of trends in near-surface wind speeds over the Baltic S.C. Pryor1,2 , R.J. Barthelmie2 and Atmospheric Physics, Risoe National Laboratory, DK4000 Roskilde, Denmark ABSTRACT Annual mean wind speeds over associated with increases in the upper quartile of the wind speed distribution and the winter season. Trends

147

Luminescence intensity in coral skeletons from Mona Island in the Caribbean Sea and its link to precipitation and wind speed  

Science Journals Connector (OSTI)

...Precipitation and wind speed in combination may thus...well as turbidity and light availability. The negative...con- trolled by wind speed, precipitation and run-off...precipitation and wind speed may control some environmental...as freshwater supply, light availability and/or...

2002-01-01T23:59:59.000Z

148

Diabatic wind speed profiles in coastal regions: Comparison of an internal boundary layer (IBL) model with observations  

Science Journals Connector (OSTI)

A model is presented to transform wind speed observations at a single height over sea ... of 100 m). Only moderate and strong winds from the sea are considered, which are particularly important for wind energy ap...

A. C. M. Beljaars; A. A. M. Holtslag; W. C. Turkenburg

1990-04-01T23:59:59.000Z

149

Application of an Improved SVM Algorithm for Wind Speed Forecasting  

Science Journals Connector (OSTI)

An improved Support Vector Machine (SVM) algorithm is used to forecast wind in Doubly Fed Induction Generator (DFIG) wind power system without aerodromometer. The ... Validation (CV) method. Finally, 3.6MW DFIG w...

Huaqiang Zhang; Xinsheng Wang; Yinxiao Wu

2011-01-01T23:59:59.000Z

150

Anemometer Data (Wind Speed, Direction) for YKHC-Bethel, AK (2003 - 2004) |  

Open Energy Info (EERE)

YKHC-Bethel, AK (2003 - 2004) YKHC-Bethel, AK (2003 - 2004) Dataset Summary Description Wind data collected from YKHC - Bethel in Alaska from an anemometer as part of the Native American anemometer loan program. Monthly mean wind speed is available for 2003 through 2004, as is wind direction and turbulence data. Data is reported from a height of 20 m. The data was originally made available by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs is available http://www.windpoweringamerica.gov/anemometerloans/projects.asp. Source EERE Date Released November 09th, 2010 (4 years ago) Date Updated November 09th, 2010 (4 years ago) Keywords wind wind direction wind speed

151

Wind speed forecasting at different time scales: a non parametric approach  

E-Print Network [OSTI]

The prediction of wind speed is one of the most important aspects when dealing with renewable energy. In this paper we show a new nonparametric model, based on semi-Markov chains, to predict wind speed. Particularly we use an indexed semi-Markov model, that reproduces accurately the statistical behavior of wind speed, to forecast wind speed one step ahead for different time scales and for very long time horizon maintaining the goodness of prediction. In order to check the main features of the model we show, as indicator of goodness, the root mean square error between real data and predicted ones and we compare our forecasting results with those of a persistence model.

D'Amico, Guglielmo; Prattico, Flavio

2013-01-01T23:59:59.000Z

152

Probability Distributions and Threshold Selection for Monte Carlo–Type Tropical Cyclone Wind Speed Forecasts  

Science Journals Connector (OSTI)

Probabilistic wind speed forecasts for tropical cyclones from Monte Carlo–type simulations are assessed within a theoretical framework for a simple unbiased Gaussian system that is based on feature size and location error that mimic tropical ...

Michael E. Splitt; Steven M. Lazarus; Sarah Collins; Denis N. Botambekov; William P. Roeder

2014-10-01T23:59:59.000Z

153

Estimation of sector roughness lengths and the effect on prediction of the vertical wind speed profile  

Science Journals Connector (OSTI)

An estimate of roughness length is required by some atmospheric models and is also used in the logarithmic profile to determine the increase of wind speed with height under neutral conditions. The choice ... thei...

R. J. Barthelmie; J. P. Palutikof; T. D. Davies

1993-10-01T23:59:59.000Z

154

WIND DATA REPORT Ragged Mt Maine  

E-Print Network [OSTI]

...................................................................................................................... 8 Wind Speed Time Series............................................................................................................. 9 Wind Speed Distributions........................................................................................................... 9 Monthly Average Wind Speeds

Massachusetts at Amherst, University of

155

Anemometer Data (Wind Speed, Direction) for Ugashik, AK (2001...  

Open Energy Info (EERE)

by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs...

156

EVALUATION OF MODELS FOR THE VERTICAL EXTRAPOLATION OF WIND SPEED MEASUREMENTS AT OFFSHORE SITES  

E-Print Network [OSTI]

EVALUATION OF MODELS FOR THE VERTICAL EXTRAPOLATION OF WIND SPEED MEASUREMENTS AT OFFSHORE SITES important for offshore wind energy utilisation are discussed and tested: Four models for the surface tested with measurements from the offshore field measurement Rødsand by extrapolating the measured 10 m

Heinemann, Detlev

157

Dynamical Downscaling of Wind Speed in Complex Terrain Prone To Bora-Type Flows  

Science Journals Connector (OSTI)

The results of numerically modeled wind speed climate, a primary component of wind energy resource assessment in the complex terrain of Croatia, are given. For that purpose, dynamical downscaling of 10 yr (1992–2001) of the 40-yr ECMWF Re-Analysis ...

Kristian Horvath; Alica Baji?; Stjepan Ivatek-Šahdan

2011-08-01T23:59:59.000Z

158

Tractable Analytic Expressions for the Wind Speed Probability Density Functions Using Expansions of Orthogonal Polynomials  

Science Journals Connector (OSTI)

The use of the two-parameter Weibull function as an estimator of the wind speed probability density function (PDF) is known to be problematic when a high accuracy of fit is required, such as in the computation of the wind power density function. ...

Mark L. Morrissey; J. Scott Greene

2012-07-01T23:59:59.000Z

159

UNIVERSITY OF CALIFORNIA, Surface Wind Speed Distributions: Implications for Climate and Wind Power  

E-Print Network [OSTI]

and Wind Power DISSERTATION submitted in partial satisfaction of the requirements for the degree of DOCTOR . . . . . . . . . . . . . . . . . 19 1.3 Global Ocean Wind Power and Surface Layer Stability . . . . . . . . 23 1.3.1 Global Winds . . . . . . 27 1.4 Usable Offshore Wind Power . . . . . . . . . . . . . . . . . . . . . . . 31 1.4.1 Wind Turbine

Zender, Charles

160

Optimal Evolutionary Wind Turbine Placement in Wind Farms Considering New Models of Shape, Orography and Wind Speed Simulation  

Science Journals Connector (OSTI)

In this paper we present a novel evolutionary algorithm for optimal positioning of wind turbines in wind farms. We consider a realistic model for the wind farm, which includes orography, shape of the wind farm, s...

B. Saavedra-Moreno; S. Salcedo-Sanz…

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Euler-Bernoulli Implementation of Spherical Anemometers for High Wind Speed Calculations via Strain Gauges  

E-Print Network [OSTI]

New measuring methods continue to be developed in the field of wind anemometry for various environments subject to low-speed and high-speed flows, turbulent-present flows, and ideal and non-ideal flows. As a result, anemometry has taken different...

Castillo, Davis

2011-08-08T23:59:59.000Z

162

Wind speed equalization-based incoming wind classification by aggregating DFIGs  

Science Journals Connector (OSTI)

With the development of wind energy, it is necessary to develop equivalent models to represent dynamic behaviors of wind farms in power systems. The equivalent wind method is investigated for the aggregation o...

Zhaojun Meng; Feng Xue; Xueming Li

2013-06-01T23:59:59.000Z

163

Wind speed and power density analysis based on Weibull and Rayleigh distributions (a case study: Firouzkooh county of Iran)  

Science Journals Connector (OSTI)

Abstract The present study aimed to analyze the wind speed data of Firouzkooh region. For this purpose, the wind speed data for a 3-h period measuring over a 10-year period (2001–2010) were analyzed to calculate and estimate the wind power generation potential. Similar trends of the wind speeds were seen in different years where the highest and the lowest mean wind speeds belonged to May 2010 and June 2002, respectively. The diurnal wind speed analysis demonstrated that the fastest winds blew from 6 am to 3 pm. Weibull and Rayleigh distribution functions were applied to find out the best fitting tool to the wind speed data. Results showed that Weibull and Rayleigh distribution functions can fit the actual values of wind speed well with almost the same coefficient of determination value (R2) of 0.97. The average values of wind power based on mean and root mean cube speed approaches were 203 and 248 W m?2 year?1, respectively indicating that Firouzkooh region stands in class 4 (which is a suitable area for wind turbine establishment). Finally, wind rose diagram revealed that the prevailing wind direction falls in the sector between 180° and 270° clockwise from North.

S.H. Pishgar-Komleh; A. Keyhani; P. Sefeedpari

2015-01-01T23:59:59.000Z

164

A study of wind-speed maxima near the surface over the south central United States  

E-Print Network [OSTI]

-1960) and the Oklahoma City radiosonde station data for the time period June, 1966 to May, 1967. They also showed that the higher the monthly, mean, wind speed, the more likely that the wind direction was from the south. Bonner (1968) states, "Strong early morning...) (Member) (Member) May 1973 ABSTRACT A Study of Wind-Speed Maxima near the Surface over the South Central United States (May 1973) Samuel K. Beckman, B. S. , Kansas State University Directed by: Professor Walter K. Henry Radiosonde and rawinsonde...

Beckman, Samuel Karl

2012-06-07T23:59:59.000Z

165

Spatial Variation and Interpolation of Wind Speed Statistics and Its Implication in Design Wind Load.  

E-Print Network [OSTI]

??Consideration of wind load is important for design of engineered structures. Codification of wind load for structural design requires the estimation of the quantiles or… (more)

Ye, Wei

2013-01-01T23:59:59.000Z

166

Unexpected vertical wind speed profiles in the boundary layer over the southern North Sea  

Science Journals Connector (OSTI)

Abstract Shallow atmospheric internal boundary layers over the southern part of the North Sea are common. Analysis of one year of meteorological data from the FINO1 research platform in the German Bight reveals that vertical wind speed profiles frequently do not conform to the expected modified logarithmic profile of Monin–Obukhov similarity theory. The wind profiles are mostly characterized by local maxima or kinks within the first 100 m over the sea surface. The data reveals the most frequent occurrence of a single maximum, but multiple maxima are often present, and there are sometimes even reversed profiles with the wind speed decreasing with height. The expected modified logarithmic profile occurs for a minority of cases. The evidence suggests the frequent presence of internal boundary layers that propagate from coastal land masses that surround the North Sea. A census of vertical wind speed profiles is presented that shows how different inflection states are linked with wind speed and atmospheric stability. The kinks are most prevalent in the upper part of the measurement range near the 100 m hub height of modern offshore the wind turbines, so that internal boundary layers represent a possible concern for the offshore wind energy industry in the North Sea region.

Anthony J. Kettle

2014-01-01T23:59:59.000Z

167

100-Year Return Value Estimates for Ocean Wind Speed and Significant Wave Height from the ERA-40 Data  

E-Print Network [OSTI]

and time variability of significant wave height and wind speed on the prediction of their extreme values of this dataset makes it ideal for the study of extreme wind and wave phenomena over the whole globe. Initial100-Year Return Value Estimates for Ocean Wind Speed and Significant Wave Height from the ERA-40

Haak, Hein

168

CONSTRAINING HIGH-SPEED WINDS IN EXOPLANET ATMOSPHERES THROUGH OBSERVATIONS OF ANOMALOUS DOPPLER SHIFTS DURING TRANSIT  

SciTech Connect (OSTI)

Three-dimensional (3D) dynamical models of hot Jupiter atmospheres predict very strong wind speeds. For tidally locked hot Jupiters, winds at high altitude in the planet's atmosphere advect heat from the day side to the cooler night side of the planet. Net wind speeds on the order of 1-10 km s{sup -1} directed towards the night side of the planet are predicted at mbar pressures, which is the approximate pressure level probed by transmission spectroscopy. These winds should result in an observed blueshift of spectral lines in transmission on the order of the wind speed. Indeed, Snellen et al. recently observed a 2 {+-} 1 km s{sup -1} blueshift of CO transmission features for HD 209458b, which has been interpreted as a detection of the day-to-night (substellar to anti-stellar) winds that have been predicted by 3D atmospheric dynamics modeling. Here, we present the results of a coupled 3D atmospheric dynamics and transmission spectrum model, which predicts the Doppler-shifted spectrum of a hot Jupiter during transit resulting from winds in the planet's atmosphere. We explore four different models for the hot Jupiter atmosphere using different prescriptions for atmospheric drag via interaction with planetary magnetic fields. We find that models with no magnetic drag produce net Doppler blueshifts in the transmission spectrum of {approx}2 km s{sup -1} and that lower Doppler shifts of {approx}1 km s{sup -1} are found for the higher drag cases, results consistent with-but not yet strongly constrained by-the Snellen et al. measurement. We additionally explore the possibility of recovering the average terminator wind speed as a function of altitude by measuring Doppler shifts of individual spectral lines and spatially resolving wind speeds across the leading and trailing terminators during ingress and egress.

Miller-Ricci Kempton, Eliza [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Rauscher, Emily, E-mail: ekempton@ucolick.org [Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721 (United States)

2012-06-01T23:59:59.000Z

169

A novel voltage and frequency controller for standalone DFIG based Wind Energy Conversion System  

Science Journals Connector (OSTI)

Abstract This paper presents a new speed-sensorless control strategy for a stand-alone doubly-fed induction generator supplying energy to an isolated load. The method is based on the root mean square (rms) detection scheme. The generated stator voltage is controlled via rotor currents. Amplitude of stator voltage and its frequency are controlled simultaneously. The output signals from the voltage controllers are the reference signals for the rotor current amplitude and frequency of the stator voltage is regulated with the help of frequency control loop. This developed direct voltage control method is applicable for both the balanced and unbalanced load and also for standalone and grid connected mode. The control pulses for the rotor side converter is supplied by the hysteresis controller which is operated on the error signal calculated between actual and reference rotor currents. This paper also provides the brief idea about the voltage and frequency control on modern Autonomous DFIG based Wind Energy Systems via single phase mathematical model of standalone DFIG system. A short state-of-the-art review on mechanical position/speed sensorless control schemes for autonomous DFIG based \\{WESs\\} is presented, which helps the present researcher and students working in this area. These include stator flux oriented control techniques; direct voltage control techniques; MARS observer based techniques for autonomous DFIG-based variable-speed WESs. Simulation results obtained from a 2MVA DFIG system, prototype in MATLab/Simulink, are presented and discussed in this paper.

Rishabh Dev Shukla; Ramesh Kumar Tripathi

2014-01-01T23:59:59.000Z

170

The Influence of Boundary Layer Processes on the Diurnal Variation of the Climatological Near-Surface Wind Speed Probability Distribution over Land  

Science Journals Connector (OSTI)

Knowledge of the diurnally varying land surface wind speed probability distribution is essential for surface flux estimation and wind power management. Global observations indicate that the surface wind speed probability density function (PDF) is ...

Yanping He; Norman A. McFarlane; Adam H. Monahan

2012-09-01T23:59:59.000Z

171

Adaptive pitch control for variable speed wind turbines  

DOE Patents [OSTI]

An adaptive method for adjusting blade pitch angle, and controllers implementing such a method, for achieving higher power coefficients. Average power coefficients are determined for first and second periods of operation for the wind turbine. When the average power coefficient for the second time period is larger than for the first, a pitch increment, which may be generated based on the power coefficients, is added (or the sign is retained) to the nominal pitch angle value for the wind turbine. When the average power coefficient for the second time period is less than for the first, the pitch increment is subtracted (or the sign is changed). A control signal is generated based on the adapted pitch angle value and sent to blade pitch actuators that act to change the pitch angle of the wind turbine to the new or modified pitch angle setting, and this process is iteratively performed.

Johnson, Kathryn E. (Boulder, CO); Fingersh, Lee Jay (Westminster, CO)

2012-05-08T23:59:59.000Z

172

Effects of high-frequency wind sampling on simulated mixed layer depth and upper ocean temperature  

E-Print Network [OSTI]

Effects of high-frequency wind sampling on simulated mixed layer depth and upper ocean temperature. Citation: Lee, T., and W. T. Liu (2005), Effects of high-frequency wind sampling on simulated mixed layer 2005. [1] Effects of high-frequency wind sampling on a near-global ocean model are studied by forcing

Talley, Lynne D.

173

Probabilistic Forecasts of Wind Speed: Ensemble Model Output Statistics  

E-Print Network [OSTI]

. Over the past two decades, ensembles of numerical weather prediction (NWP) models have been developed and phrases: Continuous ranked probability score; Density forecast; Ensem- ble system; Numerical weather prediction; Heteroskedastic censored regression; Tobit model; Wind energy. 1 #12;1 Introduction Accurate

Washington at Seattle, University of

174

Research on Control System of High Power DFIG Wind Power System  

Science Journals Connector (OSTI)

Compared with constant speed constant frequency wind turbine, variable speed constant frequency wind turbine has many advantages: higher efficiency of wind energy converting to electric power, absorbing gust energy, smoothly cutting into the network ... Keywords: wind power, DFIG, high power, LQR, variable speed constant frequency, constant power control

Li Jianlin; Xu Honghua

2008-12-01T23:59:59.000Z

175

Intense and Extreme Wind Speeds Observed by Anemometer and Seismic Networks: An Eastern U.S. Case Study  

Science Journals Connector (OSTI)

The scale and intensity of extreme wind events have tremendous relevance to determining the impact on infrastructure and natural and managed ecosystems. Analyses presented herein show the following. 1) Wind speeds in excess of the station-specific ...

S. C. Pryor; R. Conrick; C. Miller; J. Tytell; R. J. Barthelmie

2014-11-01T23:59:59.000Z

176

Measurement of the Speed of Light. I. Introduction and Frequency Measurement of a Carbon Dioxide Laser  

Science Journals Connector (OSTI)

30 June 1977 research-article Measurement of the Speed of Light. I. Introduction and Frequency Measurement of a Carbon...part II following, describe a determination of the speed of light made by measuring the frequency and wavelength of radiation...

1977-01-01T23:59:59.000Z

177

Standardization of raw wind speed data under complex terrain conditions: A data-driven scheme  

Science Journals Connector (OSTI)

Abstract Direct usage of raw wind data without modification of topographic and/or terrain effects may result in remarkable errors. Thus, standardization of raw wind datasets is of great importance to remove these influences. But, the existing standardization methods are mainly applicable for flat terrains, which may become inappropriate under complex terrain conditions. This paper presents a data-driven standardization scheme which can be applied for different terrains including complex terrains. Although this scheme is established based on wind profile records at a reference station equipped with both an anemometer at a near-ground height and a Doppler radar profiler system, it can be used for the standardization of surface winds not only at the reference station but also at other surrounding stations with only surface observation instruments. Thus, the proposed data-driven scheme is efficient and economic. As applications of this scheme, correction factors to convert raw wind speeds at about 50 weather stations in Hong Kong to those over a reference terrain are estimated. To verify the effectiveness of the proposed standardization scheme, a wind tunnel testing involved the topographic model of a weather station has been conducted. The standardization results via the proposed scheme and the wind tunnel testing are in good agreement. The proposed methodology and relevant results can be used for the analysis of topographic effects on wind speeds over complex terrains.

Y.C. He; P.W. Chan; Q.S. Li

2014-01-01T23:59:59.000Z

178

Wind speed modeled as a semi-Markov process with memory  

E-Print Network [OSTI]

The increasing interest in renewable energy, particularly in wind, has given rise to the necessity of accurate models for the generation of good synthetic wind speed data. Markov chains are often used with this purpose but better models are needed to reproduce the statistical properties of wind speed data. In a previous paper we showed that semi-Markov processes are more appropriate for this purpose but to reach an accurate reproduction of real data features high order model should be used. In this work we introduce an indexed semi-Markov process that is able to fit real data. We downloaded a database, freely available from the web, in which are included wind speed data taken from L.S.I. -Lastem station (Italy) and sampled every 10 minutes. We then generate synthetic time series for wind speed by means of Monte Carlo simulations. The time lagged autocorrelation is then used to compare statistical properties of the proposed model with those of real data and also with a synthetic time series generated though a ...

D'Amico, Guglielmo; Prattico, Flavio

2012-01-01T23:59:59.000Z

179

On the relationship between temperature and wind speed in the atmospheric surface layer  

E-Print Network [OSTI]

LIBRAR& A AN m os??E " "" ON THE RELATIONSHIP BETWEEN T" MP. "RATURE AND WIND SPEED IN THE ATMOSPHERIC SURFACE LAYER A Thesis John Me Pierrard Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial... logarithmically with height+ Also, the choice of a method of determination of the roughness length must be governed by an awareness of possible errors in the wind speed meas- urementso The system used to collect the data employed in this study is susceptible...

Pierrard, John Martin

2012-06-07T23:59:59.000Z

180

Fluctuating wind power penetration as limited by frequency standard.  

E-Print Network [OSTI]

??Fluctuating wind power is due to wind turbulence and is the part which should be filtered out leaving behind the more predictable mean wind power… (more)

Luo, Changling, 1980-

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

The Influence of Boundary Layer Processes on the Diurnal Variation of the Climatological Near-Surface Wind Speed Probability Distribution over Land*  

E-Print Network [OSTI]

diurnally varying vertical structure of the leading three climatological moments of near-surface wind speed-Surface Wind Speed Probability Distribution over Land* YANPING HE School of Earth and Ocean Sciences wind speed probability distribution is essential for surface flux estimation and wind power management

He, Yanping

182

Anemometer Data (Wind Speed, Direction) for Pascua Yaqui, AZ (2003 - 2004)  

Open Energy Info (EERE)

Pascua Yaqui, AZ (2003 - 2004) Pascua Yaqui, AZ (2003 - 2004) Dataset Summary Description Wind data collected from Pascua Yaqui Indian Reservation in Arizona from an anemometer as part of the Native American anemometer loan program. Monthly mean wind speed is available for 2003 through 2004, as is wind direction and turbulence data. Data is reported from a height of 20 m. The data was originally made available by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs is available http://www.windpoweringamerica.gov/anemometerloans/projects.asp. Source EERE Date Released December 02nd, 2010 (3 years ago) Date Updated December 02nd, 2010 (3 years ago) Keywords wind

183

Anemometer Data (Wind Speed, Direction) for Quinault #3, WA (2004 - 2005) |  

Open Energy Info (EERE)

Quinault #3, WA (2004 - 2005) Quinault #3, WA (2004 - 2005) Dataset Summary Description Wind data collected from Quinault Indian Reservation in Washington from an anemometer as part of the Native American anemometer loan program. Monthly mean wind speed is available for 2004 through 2005, as is wind direction and turbulence data. Data is reported from a height of 20 m. The data was originally made available by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs is available http://www.windpoweringamerica.gov/anemometerloans/projects.asp. Source EERE Date Released December 02nd, 2010 (4 years ago) Date Updated December 02nd, 2010 (4 years ago) Keywords wind

184

Spatial distribution of very low?frequency wind?generated noise in the ocean  

Science Journals Connector (OSTI)

We have adapted our model of surface?generated noise in a stratified lossy ocean to the case of low?frequency wind?generated noise produced in deep water by turbulentpressure fluctuations in the atmosphere. The model assumes a random pressure distribution at the surface and includes the effects of sound?speed profile and bottom characteristics. Using Wilson's source levels [J. H. Wilson J. Acoust. Soc. Am. 66 1499–1507 (1979)] we have calculated the noise level as functions of frequency and depth and compared the results with measured data. We show these results along with calculations of the spatial coherence function which differs significantly from the standard deep?water result. Finally we present calculations of the effective surface area that is the area of the surface centered above the receiver which contributes most of the noise intensity. We show that this quantity is dependent on receiver depth.

F. Ingenito; W. A. Kuperman

1980-01-01T23:59:59.000Z

185

Creating Synthetic Wind Speed Time Series for 15 New Zealand Wind Farms  

Science Journals Connector (OSTI)

Wind data at time scales from 10 min to 1 h are an important input for modeling the performance of wind farms and their impact on many countries’ national electricity systems. Planners need long-term realistic (i.e., meteorologically spatially and ...

Richard Turner; Xiaogu Zheng; Neil Gordon; Michael Uddstrom; Greg Pearson; Rilke de Vos; Stuart Moore

2011-12-01T23:59:59.000Z

186

Solar wind suprathermal electron Stahl widths across high-speed stream structures  

SciTech Connect (OSTI)

Suprathermal electrons (100-1500 eV) observed in the solar wind typically show a strahl distribution, that is, a beam directed away from the Sun along the magnetic field direction. The strahl width observed at 1 AU is highly variable, ranging from 10-70 degrees. The obsenred finite width of the strahl results from the competition between beam focusing as the interplanetary magnetic field strength drops with distance from the Sun, and pitch-angle scattering as the beam interacts with the solar wind plasma in transit from the sun. Here we examine strahl width, observed with ACE SWEPAM across high-speed stream structures to investigate variations in electron scattering as a function of local plasma characteristics. We find that narrow strahls (less than 20 degrees wide), indicating reduced scattering, are observed within high-speed streams. Narrow strahls are also observed in both very low temperature solar wind, in association with ICMEs. Case studies of high-speed streams typically show the strahl narrowing at the leading edge of the stream. In some cases, the strahl narrows at the reverse shock or pressure wave, in other cases at the stream interface. The narrowing can either occur discontinuously or gradually over a period of hours. Within the high-speed wind, the strahl remains narrow for a period of hours to days, and then gradually broadens. The strahl width is roughly constant at all energies across these structures. For some fraction of high-speed streams, counterstreaming is associated with passage of the corotating interaction region. In these cases, we find the widths of the two counterstreaming beams frequently differ by more than 40 degrees. This dramatic difference in strahl width contrasts with observations in the solar wind as a whole, in which counterstreaming strahls typically differ in width by less than 20 degrees.

Skoug, Ruth M [Los Alamos National Laboratory; Steinberg, John T [Los Alamos National Laboratory; Goodrich, Katherine A [Los Alamos National Laboratory; Anderson, Brett R [DARTMUTH UNIV.

2011-01-03T23:59:59.000Z

187

Documenting Wind Speed and Power Deficits behind a Utility-Scale Wind Turbine  

Science Journals Connector (OSTI)

High-spatial-and-temporal-resolution radial velocity measurements surrounding a single utility-scale wind turbine were collected using the Texas Tech University Ka-band mobile research radars. The measurements were synthesized to construct the ...

Brian D. Hirth; John L. Schroeder

2013-01-01T23:59:59.000Z

188

High resolution reanalysis of wind speeds over the British Isles for wind energy integration   

E-Print Network [OSTI]

The UK has highly ambitious targets for wind development, particularly offshore, where over 30GW of capacity is proposed for development. Integrating such a large amount of variable generation presents enormous challenges. ...

Hawkins, Samuel Lennon

2012-11-29T23:59:59.000Z

189

Novel sensorless generator control and grid fault ride-through strategies for variable-speed wind turbines and implementation on a new real-time simulation platform.  

E-Print Network [OSTI]

??The usage of MW-size variable-speed wind turbines as sources of energy has increased significantly during the last decade. Advantages over fixed-speed wind turbines include more… (more)

Yang, Sheng

2010-01-01T23:59:59.000Z

190

WORM: A new open road line source model for low wind speed conditions  

Science Journals Connector (OSTI)

Emission from road traffic constitutes one of the most important sources of air pollution in urban areas. This paper describes a newly developed air pollution dispersion model for open roads and highways called WORM (Weak Wind Open Road Model), and give some results using this model at Nordbysletta, Norway, in the period 1 January 200215 April 2002. Generally, a good correspondence was found between observed and model-predicted concentrations of nitrogen oxides (NOx), even in periods with low wind speed and (strongly) stable atmospheric conditions.

S.E. Walker

2011-01-01T23:59:59.000Z

191

Fig. 1. One hour measured irradiance and wind speed data with 0.2 seconds, 3 seconds and 1 minute (interpolated) sampling time.  

E-Print Network [OSTI]

Fig. 1. One hour measured irradiance and wind speed data with 0.2 seconds, 3 seconds and 1 minute of the solar irradiance and wind speed in fast changing conditions on the utility grid. This work proposes of resolution of the solar irradiance G [W/m2 ], ambient temperature Ta [K] and wind speed v [m/s] on a study

Sera, Dezso

192

A doubly-fed permanent magnet generator for wind turbines  

E-Print Network [OSTI]

Optimum extraction of energy from a wind turbine requires that turbine speed vary with wind speed. Existing solutions to produce constant-frequency electrical output under windspeed variations are undesirable due to ...

Thomas, Andrew J. (Andrew Joseph), 1981-

2004-01-01T23:59:59.000Z

193

A Coral Reefs Optimization algorithm with Harmony Search operators for accurate wind speed prediction  

Science Journals Connector (OSTI)

Abstract This paper introduces a new hybrid bio-inspired solver which combines elements from the recently proposed Coral Reefs Optimization (CRO) algorithm with operators from the Harmony Search (HS) approach, which gives rise to the coined CRO-HS optimization technique. Specifically, this novel bio-inspired optimizer is utilized in the context of short-term wind speed prediction as a means to obtain the best set of meteorological variables to be input to a neural Extreme Learning Machine (ELM) network. The paper elaborates on the main characteristics of the proposed scheme and discusses its performance when predicting the wind speed based on the measures of two meteorological towers located in USA and Spain. The good results obtained in these experiments when compared to naďve versions of the CRO and HS algorithms are promising and pave the way towards the utilization of the derived hybrid solver in other optimization problems arising from diverse disciplines.

S. Salcedo-Sanz; A. Pastor-Sánchez; J. Del Ser; L. Prieto; Z.W. Geem

2015-01-01T23:59:59.000Z

194

Log-normal distribution based EMOS models for probabilistic wind speed forecasting  

E-Print Network [OSTI]

Ensembles of forecasts are obtained from multiple runs of numerical weather forecasting models with different initial conditions and typically employed to account for forecast uncertainties. However, biases and dispersion errors often occur in forecast ensembles, they are usually under-dispersive and uncalibrated and require statistical post-processing. We present an Ensemble Model Output Statistics (EMOS) method for calibration of wind speed forecasts based on the log-normal (LN) distribution, and we also show a regime-switching extension of the model which combines the previously studied truncated normal (TN) distribution with the LN. Both presented models are applied to wind speed forecasts of the eight-member University of Washington mesoscale ensemble, of the fifty-member ECMWF ensemble and of the eleven-member ALADIN-HUNEPS ensemble of the Hungarian Meteorological Service, and their predictive performances are compared to those of the TN and general extreme value (GEV) distribution based EMOS methods an...

Baran, Sándor

2014-01-01T23:59:59.000Z

195

Analysis of the effects of integrating wind turbines into a conventional utility: a case study. Final report  

SciTech Connect (OSTI)

The impact on a utility incorporating wind turbine generation due to wind speed sampling frequency, wind turbine performance model, and wind speed forecasting accuracy is examined. The utility analyzed in the study was the Los Angeles Department of Water and Power and the wind turbine assumed was the MOD-2. The sensitivity of the economic value of wind turbine generation to wind speed sampling frequency and wind turbine modeling technique is examined as well as the impact of wind forecasting accuracy on utility operation and production costs. Wind speed data from San Gorgonio Pass, California during 1979 are used to estimate wind turbine performance using four different simulation methods. (LEW)

Goldenblatt, M.K.; Wegley, H.L.; Miller, A.H.

1982-08-01T23:59:59.000Z

196

Analysis of the effects of integrating wind turbines into a conventional utility: a case study. Revised final report  

SciTech Connect (OSTI)

The impact on a utility incorporating wind turbine generation due to wind speed sampling frequency, wind turbine performance model, and wind speed forecasting accuracy is examined. The utility analyzed in this study was the Los Angeles Department of Water and Power, and the wind turbine assumed was the MOD-2. The sensitivity of the economic value of wind turbine generation to wind speed sampling frequency and wind turbine modeling technique is examined as well as the impact of wind forecasting accuracy on utility operation and production costs. Wind speed data from San Gorgonio Pass, California during 1979 are used to estimate wind turbine performance using four different simulation methods. (LEW)

Goldenblatt, M.K.; Wegley, H.L.; Miller, A.H.

1983-03-01T23:59:59.000Z

197

SOLAR WIND ELECTRIC FIELDS IN THE ION CYCLOTRON FREQUENCY RANGE P. J. Kellogg,1  

E-Print Network [OSTI]

SOLAR WIND ELECTRIC FIELDS IN THE ION CYCLOTRON FREQUENCY RANGE P. J. Kellogg,1 S. D. Bale,2 F. S wind in the region near the ion cyclotron frequency of protons, larger than the force due to magnetic fluctuations. They provide sufficient velocity- space diffusion or heating to counteract conservation

California at Berkeley, University of

198

Glacial Cooling in the Tropics: Exploring the Roles of Tropospheric Water Vapor, Surface Wind Speed, and Boundary Layer Processes  

Science Journals Connector (OSTI)

This paper is a modeling study of possible roles for tropospheric water vapor, surface wind speed, and boundary layer processes in glacial cooling in the Tropics. The authors divide the Tropics into a region of persistent deep convection and a ...

Richard Seager; Amy C. Clement; Mark A. Cane

2000-07-01T23:59:59.000Z

199

Magnetic-Driven Winds from Post-AGB Stars: Solutions for High Speed Winds and Extreme Collimation  

E-Print Network [OSTI]

This paper explores the effects of post-AGB winds driven solely by magnetic pressure from the stellar surface. It is found that winds can reach high speeds under this assumption, and lead to the formation of highly collimated proto-planetary nebulae. Bipolar knotty jets with periodic features and constant velocity are well reproduced by the models. Several wind models with terminal velocities from a few tens of $\\kms$ up to $10^3$ $\\kms$ are calculated, yielding outflows with linear momenta in the range $10^{36}-10^{40} \\gcms$, and kinetic energies in the range $10^{42}-10^{47} $ erg. These results are in accord with recent observations of proto-planetary nebulae that have pointed out serious energy and momentum deficits if radiation pressure is considered as the only driver for these outflows. Our models strengthen the notion that the large mass-loss rates of post-AGB stars, together with the short transition times from the late AGB to the planetary nebula stage, could be directly linked with the generation of strong magnetic fields during this transition stage.

Guillermo Garcia-Segura; Jose Alberto Lopez; Jose Franco

2004-09-24T23:59:59.000Z

200

Correlated solar wind speed, density, and magnetic field changes at J. D. Richardson and C. Wang1  

E-Print Network [OSTI]

Correlated solar wind speed, density, and magnetic field changes at Voyager 2 J. D. Richardson and C. Wang1 Center for Space Research, Massachusetts Institute of Technology, Cambridge, Massachusetts December 2003. [1] The character of the solar wind plasma data observed by Voyager 2 recently changed

Richardson, John

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Occurrence of high-speed solar wind streams over the Grand Modern Maximum  

E-Print Network [OSTI]

In the declining phase of the solar cycle, when the new-polarity fields of the solar poles are strengthened by the transport of same-signed magnetic flux from lower latitudes, the polar coronal holes expand and form non-axisymmetric extensions toward the solar equator. These extensions enhance the occurrence of high-speed solar wind streams (HSS) and related co-rotating interaction regions in the low-latitude heliosphere, and cause moderate, recurrent geomagnetic activity in the near-Earth space. Here, using a novel definition of geomagnetic activity at high (polar cap) latitudes and the longest record of magnetic observations at a polar cap station, we calculate the annually averaged solar wind speeds as proxies for the effective annual occurrence of HSS over the whole Grand Modern Maximum (GMM) from 1920s onwards. We find that a period of high annual speeds (frequent occurrence of HSS) occurs in the declining phase of each solar cycle 16-23. For most cycles the HSS activity clearly maximizes during one year...

Mursula, Kalevi; Holappa, Lauri

2015-01-01T23:59:59.000Z

202

Adaptive neuro-fuzzy evaluation of wind farm power production as function of wind speed and direction  

Science Journals Connector (OSTI)

Wind velocity assumes a critical part for measuring the power created by the wind turbines. Nonetheless, power production from wind has a few weaknesses. One significant issue is that wind is a discontinuous ener...

Dalibor Petkovi?; Shahaboddin Shamshirband…

2014-05-01T23:59:59.000Z

203

BBO-based small autonomous hybrid power system optimization incorporating wind speed and solar radiation forecasting  

Science Journals Connector (OSTI)

Abstract Rising carbon emission or carbon footprint imposes grave concern over the earth?s climatic condition, as it results in increasing average global temperature. Renewable energy sources seem to be the favorable solution in this regard. It can reduce the overall energy consumption rate globally. However, the renewable sources are intermittent in nature with very high initial installation price. Off-grid Small Autonomous Hybrid Power Systems (SAHPS) are good alternative for generating electricity locally in remote areas, where the transmission and distribution of electrical energy generated from conventional sources are otherwise complex, difficult and costly. In optimizing SAHPS, weather data over past several years are generally the main input, which include wind speed and solar radiation. The weather resources used in this optimization process have unsystematic variations based on the atmospheric and seasonal phenomenon and it also varies from year to year. While using past data in the analysis of SAHPS performance, it was assumed that the same pattern will be followed in the next year, which in reality is very unlikely to happen. In this paper, we use BBO optimization algorithm for SAHPS optimal component sizing by minimizing the cost of energy. We have also analysed the effect of using forecast weather data instead of past data on the SAHPS performance. ANNs, which are trained with back-propagation training algorithm, are used for wind speed and solar radiation forecasting. A case study was used for demonstrating the performance of BBO optimization algorithm along with forecasting effects. The simulation results clearly showed the advantages of utilizing wind speed and solar radiation forecasting in a SAHPS optimization problem.

R.A. Gupta; Rajesh Kumar; Ajay Kumar Bansal

2015-01-01T23:59:59.000Z

204

The effect of wind speed and direction and surrounding maize on hybrid ventilation in a dairy cow building in Denmark  

Science Journals Connector (OSTI)

Abstract This study evaluated the effect of wind speed and direction and surrounding maize field on the air exchange rate (ACH) and indoor air velocity in a dairy cow building with hybrid ventilation, which combined auto-controlled natural and partial mechanical pit ventilation. The standard k ? ? turbulence model and standard wall function were applied in CFD modeling with extension of capability to account for the aerodynamics effect of surrounding maize plant canopy in the wind domain by using user defined functions (UDF). This extended model was validated by on-site measured velocities and temperatures. A reasonably good agreement was found between simulated and measured results. The wind speed influenced ACH greatly while modeling the maize field had little effect on ACH with low wind speed. With wind speed of 3.86 m s?1 in validation case, modeling the maize field reduced total ACH by 24%, ACH via bottom openings on the sidewall by 89.7% and air speed measured upwind by 71%. The results revealed that the plant canopy had the most significant effect on ACH through the opening on the sidewall. With the variation of wind direction from 0° to 90°, the difference of ACH could be 60%.

L. Rong; D. Liu; E.F. Pedersen; G. Zhang

2015-01-01T23:59:59.000Z

205

Effect of Tip-Speed Constraints on the Optimized Design of a Wind Turbine  

SciTech Connect (OSTI)

This study investigates the effect of tip-velocity constraints on system levelized cost of energy (LCOE). The results indicate that a change in maximum tip speed from 80 to 100~m/s could produce a 32% decrease in gearbox weight (a 33% reduction in cost) which would result in an overall reduction of 1%-9% in system LCOE depending on the design approach. Three 100~m/s design cases were considered including a low tip-speed ratio/high-solidity rotor design, a high tip-speed ratio/ low-solidity rotor design, and finally a flexible blade design in which a high tip-speed ratio was used along with removing the tip deflection constraint on the rotor design. In all three cases, the significant reduction in gearbox weight caused by the higher tip-speed and lower overall gear ratio was counterbalanced by increased weights for the rotor and/or other drivetrain components and the tower. As a result, the increased costs of either the rotor or drivetrain components offset the overall reduction in turbine costs from down-sizing the gearbox. Other system costs were not significantly affected, whereas energy production was slightly reduced in the 100~m/s case low tip-speed ratio case and increased in the high tip-speed ratio case. This resulted in system cost of energy reductions moving from the 80~m/s design to the 100~m/s designs of 1.2% for the low tip-speed ratio, 4.6% for the high tip-speed ratio, and 9.5% for the final flexible case (the latter result is optimistic because the impact of deflection of the flexible blade on power production was not modeled). Overall, the results demonstrate that there is a trade-off in system design between the maximum tip velocity and the overall wind plant cost of energy, and there are many trade-offs within the overall system in designing a turbine for a high maximum tip velocity.

Dykes, K.; Resor, B.; Platt, A.; Guo, Y.; Ning, A.; King, R.; Parsons, T.; Petch, D.; Veers, P.

2014-10-01T23:59:59.000Z

206

Coronal Heating and Acceleration of the High/Low-Speed Solar Wind by Fast/Slow MHD Shock Trains  

E-Print Network [OSTI]

We investigate coronal heating and acceleration of the high- and low-speed solar wind in the open field region by dissipation of fast and slow magnetohydrodynamical (MHD) waves through MHD shocks. Linearly polarized \\Alfven (fast MHD) waves and acoustic (slow MHD) waves travelling upwardly along with a magnetic field line eventually form fast switch-on shock trains and hydrodynamical shock trains (N-waves) respectively to heat and accelerate the plasma. We determine one dimensional structure of the corona from the bottom of the transition region (TR) to 1AU under the steady-state condition by solving evolutionary equations for the shock amplitudes simultaneously with the momentum and proton/electron energy equations. Our model reproduces the overall trend of the high-speed wind from the polar holes and the low-speed wind from the mid- to low-latitude streamer except the observed hot corona in the streamer. The heating from the slow waves is effective in the low corona to increase the density there, and plays an important role in the formation of the dense low-speed wind. On the other hand, the fast waves can carry a sizable energy to the upper level to heat the outer corona and accelerate the high-speed wind effectively. We also study dependency on field strength, $B_0$, at the bottom of the TR and non-radial expansion of a flow tube, $f_{\\rm max}$, to find that large $B_0/f_{\\rm max}\\gtrsim 2$ but small $B_0\\simeq 2$G are favorable for the high-speed wind and that small $B_0/f_{\\rm max}\\simeq 1$ is required for the low-speed wind.

Takeru K. Suzuki

2003-12-22T23:59:59.000Z

207

A data mining approach: Analyzing wind speed and insolation period data in Turkey for installations of wind and solar power plants  

Science Journals Connector (OSTI)

Wind and solar power plant installations have been recently increased rapidly with respect to the depletion of fossil-based fuels all over the world. Due to stochastic nature of meteorological conditions, wind and solar energies have a non-schedulable nature and they require several installation analyses to determine the location and the capacities of wind and solar power to be produced. This paper focuses on the similarity, feasibility and numerical analyses of 75 cities in Turkey based on the monthly average wind speed and insolation period data. The nearest and the farest neighbor algorithms are used as agglomerative hierarchical clustering methods with Euclidean, Manhattan and Minkowski distance metrics in the stage of making the similarity and feasibility analyses. The maximum cophenetic correlation coefficient is achieved by the nearest neighbor algorithm with the Minkowski distance metric in the similarity and feasibility analyses. On the other hand, graphical representations of the monthly average wind speed and insolation period data are utilized for making the numerical analysis. The highest annual average wind speed and insolation period are obtained as 3.88 m/s and 8.45 h/day, respectively. Overall, many inferences were achieved in acceptable and efficient limits for wind and solar energy.

Ilhami Colak; Seref Sagiroglu; Mehmet Demirtas; Mehmet Yesilbudak

2013-01-01T23:59:59.000Z

208

Wind Speed Estimation and Parametrization of Wake Models for Downregulated Offshore Wind Farms within the scope of PossPOW Project  

Science Journals Connector (OSTI)

With increasing installed capacity, wind farms are requested to downregulate more frequently, especially in the offshore environment. Determination and verification of possible (or available) power of downregulated offshore wind farms are the aims of the PossPOW project (see PossPOW.dtu.dk). Two main challenges encountered in the project so far are the estimation of wind speed and the recreation of the flow inside the downregulated wind farm as if it is operating ideally. The rotor effective wind speed was estimated using power, pitch angle and rotational speed as inputs combined with a generic Cp model. The results have been compared with Horns Rev-I dataset and NREL 5MW simulations under both downregulation and normal operation states. For the real-time flow recreation, the GCLarsen single wake model was re-calibrated using a 1-s dataset from Horns Rev and tested for the downregulated period. The re-calibrated model has to be further parametrized to include dynamic effects such as wind direction variability and meandering also considering different averaging time scales before implemented in full scale wind farms.

Tuhfe Göçmen Bozkurt; Gregor Giebel; Niels Kjřlstad Poulsen; Mahmood Mirzaei

2014-01-01T23:59:59.000Z

209

STATCOM based voltage-frequency regulation for SEIG driven by an uncontrolled speed turbine  

Science Journals Connector (OSTI)

This article presents the analysis and the control of a stand-alone self excited induction generator (SEIG) intended for rural applications. SEIG along with the STATCOM with battery energy storage (BES) in its DC side makes it possible to control the terminal voltage and frequency during rotor speed and load variation. Constant frequency control is carried out by the load angle '?', without rotor speed control, while constant terminal voltage control is achieved via the modulation index 'm'. The 'SEIG' magnetisation characteristic and the 'STATCOM' rating are taken into consideration to determine the load interval where the terminal voltage and frequency can be controlled. The simulation results show good performances of the SEIG-STATCOM system under different perturbations.

Azzeddine Benlamoudi; Rachid Abdessemed

2009-01-01T23:59:59.000Z

210

A wind-tunnel investigation of the wind speed and turbulence characteristics close to the ground over various escarpment shapes  

Science Journals Connector (OSTI)

A wind-tunnel investigation of the wind flow over two-dimensional forward-facing escarpments ... into the effects of local topography on the wind flow close to the ground. Four sharp ... -wire anemometer. The mod...

A. J. Bowen; D. Lindley

1977-10-01T23:59:59.000Z

211

EVOLUTION OF THE RELATIONSHIPS BETWEEN HELIUM ABUNDANCE, MINOR ION CHARGE STATE, AND SOLAR WIND SPEED OVER THE SOLAR CYCLE  

SciTech Connect (OSTI)

The changing relationships between solar wind speed, helium abundance, and minor ion charge state are examined over solar cycle 23. Observations of the abundance of helium relative to hydrogen (A{sub He} {identical_to} 100 Multiplication-Sign n{sub He}/n{sub H}) by the Wind spacecraft are used to examine the dependence of A{sub He} on solar wind speed and solar activity between 1994 and 2010. This work updates an earlier study of A{sub He} from 1994 to 2004 to include the recent extreme solar minimum and broadly confirms our previous result that A{sub He} in slow wind is strongly correlated with sunspot number, reaching its lowest values in each solar minima. During the last minimum, as sunspot numbers reached their lowest levels in recent history, A{sub He} continued to decrease, falling to half the levels observed in slow wind during the previous minimum and, for the first time observed, decreasing even in the fastest solar wind. We have also extended our previous analysis by adding measurements of the mean carbon and oxygen charge states observed with the Advanced Composition Explorer spacecraft since 1998. We find that as solar activity decreased, the mean charge states of oxygen and carbon for solar wind of a given speed also fell, implying that the wind was formed in cooler regions in the corona during the recent solar minimum. The physical processes in the coronal responsible for establishing the mean charge state and speed of the solar wind have evolved with solar activity and time.

Kasper, J. C.; Stevens, M. L.; Korreck, K. E.; Maruca, B. A.; Kiefer, K. K. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Schwadron, N. A. [Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, NH 03824 (United States); Lepri, S. T. [Department of Atmospheric, Oceanic and Space Studies, University of Michigan, Ann Arbor, MI 48109 (United States)

2012-02-01T23:59:59.000Z

212

Cross-Spectrum of Wind Speed for Meso-Gamma Scales in the Upper Surface Layer over South-Eastern Australia  

Science Journals Connector (OSTI)

Analytical expressions for the cross-spectrum of wind speed are developed for the stochastic simulation of wind power in south-eastern Australia. The expressions...?1.... The influence of site separation distance...

Milton J. Woods; Robert J. Davy; Christopher J. Russell…

2011-10-01T23:59:59.000Z

213

Directional Spectra of Wind-Generated Waves  

Science Journals Connector (OSTI)

...H. Hui From observations of wind and of water surface elevation...the directional spectrum of wind-generated waves on deep water...inversely proportional to the fourth power of the frequency , with the...clearly dependent on the ratio of wind speed to peak wave speed...

1985-01-01T23:59:59.000Z

214

LIDAR Wind Speed Measurement Analysis and Feed-Forward Blade Pitch Control for Load Mitigation in Wind Turbines: January 2010--January 2011  

SciTech Connect (OSTI)

This report examines the accuracy of measurements that rely on Doppler LIDAR systems to determine their applicability to wind turbine feed-forward control systems and discusses feed-forward control system designs that use preview wind measurements. Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feed-forward control systems designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. The first half of this report examines the accuracy of different measurement scenarios that rely on coherent continuous-wave or pulsed Doppler LIDAR systems to determine their applicability to feed-forward control. In particular, the impacts of measurement range and angular offset from the wind direction are studied for various wind conditions. A realistic case involving a scanning LIDAR unit mounted in the spinner of a wind turbine is studied in depth with emphasis on choices for scan radius and preview distance. The effects of turbulence parameters on measurement accuracy are studied as well. Continuous-wave and pulsed LIDAR models based on typical commercially available units were used in the studies present in this report. The second half of this report discusses feed-forward control system designs that use preview wind measurements. Combined feedback/feed-forward blade pitch control is compared to industry standard feedback control when simulated in realistic turbulent above-rated winds. The feed-forward controllers are designed to reduce fatigue loads, increasing turbine lifetime and therefore reducing the cost of energy. Three feed-forward designs are studied: non-causal series expansion, Preview Control, and optimized FIR filter. The input to the feed-forward controller is a measurement of incoming wind speeds that could be provided by LIDAR. Non-causal series expansion and Preview Control methods reduce blade root loads but increase tower bending in simulation results. The optimized FIR filter reduces loads overall, keeps pitch rates low, and maintains rotor speed regulation and power capture, while using imperfect wind measurements provided by the spinning continuous-wave LIDAR model.

Dunne, F.; Simley, E.; Pao, L.Y.

2011-10-01T23:59:59.000Z

215

Repetitive substorms caused by Alfvenic waves of the interplanetary magnetic field during high-speed solar wind streams  

E-Print Network [OSTI]

, but they may be locally generated from stream-stream interaction effects or amplified Alfve´n waves originating-speed solar wind streams D.-Y. Lee,1 L. R. Lyons,2 K. C. Kim,1 J.-H. Baek,3 K.-H. Kim,3 H.-J. Kim,1 J. Weygand wind streams, J. Geophys. Res., 111, A12214, doi:10.1029/2006JA011685. 1. Introduction [2] During

Lyons, Larry

216

Feature selection in wind speed prediction systems based on a hybrid coral reefs optimization – Extreme learning machine approach  

Science Journals Connector (OSTI)

Abstract This paper presents a novel approach for short-term wind speed prediction based on a Coral Reefs Optimization algorithm (CRO) and an Extreme Learning Machine (ELM), using meteorological predictive variables from a physical model (the Weather Research and Forecast model, WRF). The approach is based on a Feature Selection Problem (FSP) carried out with the CRO, that must obtain a reduced number of predictive variables out of the total available from the WRF. This set of features will be the input of an ELM, that finally provides the wind speed prediction. The CRO is a novel bio-inspired approach, based on the simulation of reef formation and coral reproduction, able to obtain excellent results in optimization problems. On the other hand, the ELM is a new paradigm in neural networks’ training, that provides a robust and extremely fast training of the network. Together, these algorithms are able to successfully solve this problem of feature selection in short-term wind speed prediction. Experiments in a real wind farm in the USA show the excellent performance of the CRO–ELM approach in this FSP wind speed prediction problem.

S. Salcedo-Sanz; A. Pastor-Sánchez; L. Prieto; A. Blanco-Aguilera; R. García-Herrera

2014-01-01T23:59:59.000Z

217

Optimisation of voltage and frequency regulation in an isolated wind-driven six-phase self-excited induction generator  

Science Journals Connector (OSTI)

Abstract This paper presents a constant voltage operation of a Six-Phase Self-Excited Induction Generator (SPSEIG) driven by a fixed speed wind turbine using an Ant colony optimisation (ACO) technique to predict the behaviour of a the machine. In this paper, an attempt has been made to estimate the excitation capacitance requirements of a SPSEIG for maintaining rated terminal voltage and frequency. The range of capacitance variation required for maintaining constant terminal voltage while supplying a load of variable magnitude is evaluated. Analytical approaches, suitable for all the configurations of shunt capacitances such as variable excitation capacitance connected across (i) single three-phase winding set only and (ii) both the three-phase winding sets of an SPSEIG for operation as a simple shunt on no load and pure resistive load, are presented. The mathematical model developed is based on loop impedance method using graph theory. It is shown that the proposed technique is very effective and useful for making the SPSEIG feasible for remote areas with wind potential. The proposed approach is tested and compared with Genetic Algorithm (GA) and Fmincon technique.

A. Senthil Kumar; Josiah L. Munda

2014-01-01T23:59:59.000Z

218

Voltage and Frequency Control in Offshore Wind Turbines Connected to Isolated Oil Platform Power Systems  

Science Journals Connector (OSTI)

Offshore wind turbines have potential to supply offshore oil and gas platforms in the North Sea with electric energy. For remote located facilities it is attractive to pursue a solution where the wind turbines and oil platform operate in an isolated system. To study the operational properties of a system with these characteristics is necessary to identify possible advantages and disadvantages. This paper demonstrates how added voltage and frequency control in wind turbines equipped with full power electronic converters can improve the voltage and frequency stability in offshore oil and gas installations. The work is based on an electrical simulation model built in the PSCAD software. In the proposed transient simulation scenarios, the voltage dip is reduced from 16% to 6%, while the frequency overshoot is reduced from 97% to 25%. These are significant improvements that should be taken into consideration when offshore wind power is evaluated as power supply to oil installations.

Atle Rygg Ĺrdal; Tore Undeland; Kamran Sharifabadi

2012-01-01T23:59:59.000Z

219

General study of the control principles and dynamic fault behaviour of variable-speed wind turbine and wind farm generic models  

Science Journals Connector (OSTI)

Abstract The interest towards generic models or sometimes also called standard models of wind turbine generators (WTGs) is significantly increasing. Mainly due to their improved power quality, better controllability and higher power extraction capability, variable-speed wind turbines driving a synchronous or an induction machine are capturing the global market. Throughout this paper, dynamic modelling and performance analysis of the generic models of the variable-speed WTGs, namely the doubly-fed induction generator and the fully-rated converter based WTGs, are achieved using integration between Matlab/Simulink and PSCAD/EMTDC simulation platforms. Later on, the performance of type-4 wind turbine driving a permanent magnet synchronous machine is analysed during fault and then compared with the case when driving a wound rotor induction machine. The differences in control principles and dynamic fault behaviour are highlighted. Afterwards, investigations on wind farm level are accomplished. A case study during which the developed generic models and the generic model of the variable-speed machine are compared is conducted. Different arrangements for the construction of the generic wind farm are considered.

Tareq Saber Abuaisha

2014-01-01T23:59:59.000Z

220

Low Speed Virtual Wind Tunnel Simulation For Educational Studies In Introducing Computational Fluid Dynamics And Flow Visualization  

E-Print Network [OSTI]

, the Low Speed Virtual Wind Tunnel simulation is created. This program cuts down on the require information from the user in order to perform a simulation. The program is capable of taking an airfoil coordinates that is generated according to the user...

Yang, Cher-Chiang

2008-05-05T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Prediction of wind speed profiles for short-term forecasting in the offshore environment R.J. Barthelmie and G. Giebel  

E-Print Network [OSTI]

in the forecast wind speed/power output might be anticipated using a directional rather than a constant bias for the calibration phase. A further advantage is that statistical techniques can predict power output directly rather than having to take the additional step of predicting power output from wind speed through the power

222

IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 23, NO. 2, JUNE 2008 551 Sliding Mode Power Control of Variable-Speed Wind  

E-Print Network [OSTI]

IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 23, NO. 2, JUNE 2008 551 Sliding Mode Power Control of Variable-Speed Wind Energy Conversion Systems Brice Beltran, Tarek Ahmed-Ali, and Mohamed El Hachemi in variable-speed wind energy conversion sys- tems (VS-WECS). These systems have two operation regions de

Paris-Sud XI, Université de

223

Criteria for low frequency and infrasound from wind?energy farms  

Science Journals Connector (OSTI)

Criteria for low frequency and infrasound were developed under contract to Kern County California to allow assessment of potential public reaction to wind?energy farm developments. Recent literature was reviewed regarding possible annoyance physical discomfort and perception of sound in the frequency range of 2–125 Hz. Criteria suggested by a number of authors were compared to determine commonality of recommended sound pressure levels versus frequency in one?third octave bands. The suggested criteria were than evaluated as to whether they addressed the issue of annoyance rather than perception. A set of criteria was then proposed which incorporated empirically derived criteria intended to minimize community reaction incorporating a 5?dB penalty for the impulsive components which are sometimes present in low frequency and infrasound produced by wind?energy farm installations. The resulting criteria represent a balance between sound pressure levels which are perceptible and those which are expected to result in community annoyance.

Jim Buntin; Robert E. Brown

1986-01-01T23:59:59.000Z

224

Choosing wind power plant locations and sizes based on electric reliability measures using multiple-year wind speed measurements  

SciTech Connect (OSTI)

To project the US potential to meet future electricity demands with wind energy, estimates of available wind resource and costs to access that resource are critical. The US Department of Energy (DOE) Energy Information Administration (EIA) annually estimates the US market penetration of wind in its Annual Energy Outlook series. For these estimates, the EIA uses wind resource data developed by the Pacific Northwest National Laboratory for each region of the country. However, the EIA multiplies the cost of windpower by several factors, some as large as 3, to account for resource quality, market factors associated with accessing the resource, electric grid impacts, and rapid growth in the wind industry. This paper examines the rationale behind these additional costs and suggests alternatives.

Milligan, M.R.; Artig, R.

1999-07-08T23:59:59.000Z

225

A study of wind speed modification and internal boundary-layer heights in a coastal region  

Science Journals Connector (OSTI)

Wind profile data within the first two kilometres of a coast have been used to study the wind field modification downstream of this surface discontinuity. The land area is generally very flat, having an overal...

Hans Bergström; Per-Erik Johansson; Ann-Sofi Smedman

1988-03-01T23:59:59.000Z

226

Impact of short-term storage on frequency response under increasing wind penetration  

Science Journals Connector (OSTI)

Abstract In this paper, the effort is to study the impact of short-term storage technology in stabilizing the frequency response under increasing wind penetration. The frequency response is studied using Automatic Generation Control (AGC) module, and is quantified in terms of Control Performance Standards (CPS). The single area IEEE Reliability Test System (RTS) was chosen, and battery storage was integrated within the AGC. The battery proved to reduce the frequency deviations and provide good CPS scores with higher penetrations of wind. The results also discuss the ability of the short term storage to benefit the system by reducing the hourly regulation deployment and the cycling undergone by conventional units, by dint of their fast response; and sheds light on the economic implications of their benefits.

Venkat Krishnan; Trishna Das; James D. McCalley

2014-01-01T23:59:59.000Z

227

Low frequency vibrations in disc brakes at high car speed. Part II: mathematical model and simulation  

Science Journals Connector (OSTI)

In the present paper, a mathematical model is constructed for judder in disc brakes at high speed. Vehicle suspension is modelled by means of finite elements. Vibration modes and frequencies are derived that can be used in the classification of modes in main and secondary based in the relative disc-calliper displacement; the finite element model is also used as well as in forced-response analysis. Brake pads are defined through the friction coefficient as a function of speed, pressure, and temperature, in light of which one may consider the various braking conditions and types of pad. Since the line of reasoning introduces equivalent-damping terms into the equations of dynamics, these equations cannot be uncoupled by means of modal transformation. Two techniques are proposed for the solution of the problem. One of these consists in an examination of the 'main-modes', while the other is based on direct integration of the quasi-uncoupled equations. A computer program has been implemented which allows the simulation of this kind of judder with different pads, brake systems and braking conditions.

R. Aviles; G. Hennequet; E. Amezua; J. Vallejo

1995-01-01T23:59:59.000Z

228

Wind Resources in Alaska | OpenEI  

Open Energy Info (EERE)

Resources in Alaska Resources in Alaska Dataset Summary Description Wind resource data for Alaska and southeast Alaska, both high resolution wind resource maps and gridded wind parameters. The two high resolution wind maps are comprised of a grid of cells each containing a single value of average wind speed (m/s) at a hub height of 30, 50, 70, and 100 meters and wind power density (W/m^2) at a hub height of 50 meters for a 40,000 square meter area. The additional gridded wind parameter data includes data for points spaced 2 kilometers apart, and include: predicted wind speed frequency distribution as well as speed and energy in 16 directions (the information needed to produce a wind rose image at a given point). Data included here as .kml files (for viewing in Google Earth). GIS shape files available for the gridded wind parameters datasets from AEDI (http://akenergyinventory.org/data.shtml).

229

Remote sensing of total integrated water vapor, wind speed, and cloud liquid water over the ocean using the Special Sensor Microwave/Imager (SSM/I)  

E-Print Network [OSTI]

A modified D-matrix retrieval method is the basis of the refined total integrated water vapor (TIWV), total integrated cloud liquid water (CLW), and surface wind speed (WS) retrieval methods that are developed. The 85 GHZ polarization difference...

Manning, Norman Willis William

2012-06-07T23:59:59.000Z

230

Effect of wind speed on the growth of the upper convective zone in a solar pond  

E-Print Network [OSTI]

[2]. The distance which the wind has to act on the surface of a pond is commonly called fetch, or fetch length. The purpose of the nets or other devices used in wind suppression is to reduce the fetch and transmit some of the energy in the waves... to the sides of the pond. Wind mixing of the upper convective zone can be thought of as converting some of the kinetic energy in the wind to potential energy in the fluid by a process called entrainment. Entrainment is defined in detail in Chapter V...

McMinn, Steven Lee

2012-06-07T23:59:59.000Z

231

Calibration of the Merrill-G.A.L.C.I.T. wind-tunnel, and a suggestion for a variable cross-section on a small high-speed wind-tunnel.  

E-Print Network [OSTI]

??Speed, power and flow inclination calibration tests run in the Merrill-GALCIT wind-tunnel are described and results presented. A description of the new balance-system is included.… (more)

Schwarzenbach, Jean Christophe

1942-01-01T23:59:59.000Z

232

HEXOS—Humidity Exchange Over the Sea A Program for Research on Water-Vapor and Droplet Fluxes from Sea of Air at Moderate to High Wind Speeds  

Science Journals Connector (OSTI)

HEXOS is an international program for the study of evaporation and spray-droplet flux from sea to air. The program includes measurements in the field at moderate-to-high wind speeds, wind-tunnel studies, instrument development, boundary-layer ...

Kristina B. Katsaros; Stuart D. Smith; Wiebe A. Oost

1987-05-01T23:59:59.000Z

233

A study of wind variability in the lower troposphere through power spectrum analysis at mesoscale frequencies  

E-Print Network [OSTI]

on the theoretical and practical application of the analysis method comes directly from this reference. B. Fundamental Assum tions of Power S ectrum Theor Consider a function of time X(t), such as wind speed, which is generated by a random process. Then the value... of the function X(t) at any particular point in time is a random variable. This random process may or may not have a Gaussian or normal distribution but it is a fundamental assumption (at least in the development of the theory) that the random process...

Cornett, John Sheldon

1966-01-01T23:59:59.000Z

234

High-Speed Optical Spectroscopy of a Cataclysmic Variable Wind: BZ Camelopardalis  

E-Print Network [OSTI]

BZ Cam is the first cataclysmic variable star with an accretion disk wind evident in its optical spectrum. The wind was found by Thorstensen, who discovered intermittent P Cygni profiles occurring simultaneously in He I 5876 Angstroms and H alpha. We have since obtained spectra with 0.4-Angstroms/pixel dispersion and 60-s time resolution. We find a wind much faster and more rapidly variable than the radiatively accelerated winds of OB stars, Wolf-Rayet stars, or luminous blue variables. Instead of showing blob ejection, the whole wind of BZ Cam appears to turn on and off. We use this to measure the acceleration law of a CV wind for the first time. The velocity increases linearly with time, attaining blue edge velocities near -3000 km/s, and absorption velocities near -1700 km/s, in 6 to 8 min after starting near rest. We also find a subsequent linear deceleration to nearly rest in 30 to 40 min, perhaps an effect of dilution as the wind expands. No periodicity from rotational outflow is obvious. This wind is erratic and incessantly variable, and perhaps bipolar and face-on, but not highly collimated. The P Cygni absorption events trace out sawtooth waves, occurring within 30 to 40 white dwarf radii from the disk. This is the approximate size of the disk, as well as the disk/wind transition region recently postulated by Knigge and Drew. We estimate a distance of 830 +/- 160 pc, and an orbital inclination i such that 12 < i(degrees) < 40.

F. A. Ringwald; T. Naylor

1997-10-02T23:59:59.000Z

235

Comparing Two Types of Magnetically- Coupled Adjustable Speed Drives with Variable Frequency Drives in Pump and Fan Applications  

E-Print Network [OSTI]

This paper presents the results from laboratory tests on MagnaDrive Corporations fixed-magnet magnetically-coupled adjustable speed drive (MC-ASD) and Coyote Electronics electromagnetic MC-ASD as compared to a typical variable frequency drive (VFD...

Anderson, K. J.; Chvala, W. D.

236

Methodology for the economic optimisation of energy storage systems for frequency support in wind power plants  

Science Journals Connector (OSTI)

Abstract This paper proposes a methodology for the economic optimisation of the sizing of Energy Storage Systems (ESSs) whilst enhancing the participation of Wind Power Plants (WPP) in network primary frequency control support. The methodology was designed flexibly, so it can be applied to different energy markets and to include different ESS technologies. The methodology includes the formulation and solving of a Linear Programming (LP) problem. The methodology was applied to the particular case of a 50 MW WPP, equipped with a Vanadium Redox Flow battery (VRB) in the UK energy market. Analysis is performed considering real data on the UK regular energy market and the UK frequency response market. Data for wind power generation and energy storage costs are estimated from literature. Results suggest that, under certain assumptions, \\{ESSs\\} can be profitable for the operator of a WPP that is providing frequency response. The ESS provides power reserves such that the WPP can generate close to the maximum energy available. The solution of the optimisation problem establishes that an ESS with a power rating of 5.3 MW and energy capacity of about 3 MW h would be enough to provide such service whilst maximising the incomes for the WPP operator considering the regular and frequency regulation UK markets.

Lewis Johnston; Francisco Díaz-González; Oriol Gomis-Bellmunt; Cristina Corchero-García; Miguel Cruz-Zambrano

2015-01-01T23:59:59.000Z

237

Quantifying high-frequency wind energy-flux into near-inertial motions in the Southeast Pacific  

Science Journals Connector (OSTI)

Wind-forced internal waves close to the inertial frequency are ubiquitous throughout the world’s oceans, but observational constraints on their global energetics and impact on subsur-face mixing remain scarce. We report on velocity measurements ...

Byron F. Kilbourne; James B. Girton

238

Western Wind and Solar Integration Study Phase 3 -- Frequency Response and Transient Stability (Report and Executive Summary)  

SciTech Connect (OSTI)

The primary objectives of Phase 3 of the Western Wind and Solar Integration Study (WWSIS-3) were to examine the large-scale transient stability and frequency response of the Western Interconnection with high wind and solar penetration, and to identify means to mitigate any adverse performance impacts via transmission reinforcements, storage, advanced control capabilities, or other alternatives.

Miller, N. W.; Shao, M.; Pajic, S.; D'Aquila, R.

2014-12-01T23:59:59.000Z

239

A fuzzy logic supervisor for active and reactive power control of a variable speed wind energy conversion system associated to a flywheel storage system  

Science Journals Connector (OSTI)

In this paper, we propose a Wind Energy Conversion System (WECS) at variable speed using a Doubly Fed Induction Generator (DFIG) controlled on the rotor side through converters. A Flywheel Energy Storage System (FESS) is connected to the studied wind generator at the DC bus in order to evaluate its capacity to participate to the ancillary services. We study the improvement of the active and reactive power quality produced by the wind generator and its effect on the load voltage regulation connected to the wind generator. For that, a fuzzy logic supervisor is established to control the FESS operation and the DC bus voltage in order to smooth the active power fluctuations due to the random wind speed variations. A control law is also described to smooth the reactive power at the connection node to the grid.

Lilia Jerbi; Lotfi Krichen; Abderrazak Ouali

2009-01-01T23:59:59.000Z

240

Influence of speed and frequency towards the automotive turbocharger turbine performance under pulsating flow conditions  

Science Journals Connector (OSTI)

Abstract The ever-increasing demand for low carbon applications in automotive industry has intensified the development of highly efficient engines and energy recovery devices. Even though there are significant developments in the alternative powertrains such as full electric, their full deployment is hindered by high costing and unattractive life-cycle energy and emission balance. Thus powertrain based on highly efficient internal combustion engines are still considered to be the mainstream for years to come. Traditionally, turbocharger has been an essential tool to boost the engine power, however in recent years it is seen as an enabling technology for engine downsizing. It is a well-known fact that a turbocharger turbine in an internal combustion engine operates in a highly pulsating exhaust flow. There are numerous studies looking into the complex interaction of the pulsating exhaust gas within the turbocharger turbine, however the phenomena is still not fully integrated into the design stage. Industry practice is still to design and match the turbine to an engine based on steady performance maps. The current work is undertaken with the mind to move one step closer towards fully integrating the pulsating flow performance into the turbocharger turbine design. This paper presents the development efforts and results from a full 3-D CFD model of a turbocharger turbine stage. The simulations were conducted at 30,000 rpm and 48,000 rpm (50% and 80% design speed respectively) for both 20 Hz and 80 Hz pulsating flow inlet conditions. Complete validation procedure using cold-flow experimental data is also described. The temporal and spatial resolutions of the incidence angle at the rotor leading edge suggest that the circumference variation is little (7%) as compared to its variation in time as the pulse progresses. The primary aim of this paper is to investigate the relationship of the turbine speed, as well as the pulsating flow frequency to its performance. It was found that there are no direct instantaneous relationship between the pulsating pressure at the turbine inlet and the turbine efficiency, except when one considers an additional parameter, namely the incidence angle. This paper also intends to investigate the potential loss of information if the performance parameters are simply averaged without considering the instantaneous effects.

M.H. Padzillah; S. Rajoo; R.F. Martinez-Botas

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Backstepping control of DFIG generators for wide-range variable-speed wind turbines  

Science Journals Connector (OSTI)

In this paper, we have presented a general study of self excited induction generator used in isolated renewable energy conversion source. Tthe behaviour of generated voltage under variable load, rotor speed and excitation capacitance is presented. Also, we have proposed a robust controller suitable in order to control the terminal DC voltage under different speed and AC load conditions for supplied an isolated DC load. The experimental characteristic curve of the generator and simulation result of proposed control scheme are presented.

Badre Bossoufi; Mohammed Karim; Ahmed Lagrioui; Mohammed Taoussi; Mohamed Larbi ElHafyani

2014-01-01T23:59:59.000Z

242

Power and Frequency Control as it Relates to Wind-Powered Generation  

E-Print Network [OSTI]

of large amounts of wind power production might requirewill be satisfactory as wind power provides an increasing64   7.2   Wind Power in Relation to System

Lacommare, Kristina S H

2011-01-01T23:59:59.000Z

243

Tuning of Strouhal number for high propulsive efficiency accurately predicts how wingbeat frequency and stroke amplitude relate and scale with size and flight speed in birds  

Science Journals Connector (OSTI)

...frequency, U is cruising speed and A bsin(theta/2...be reconsidered in this light. bird|flight|stroke...scale with size and flight speed in birds. | The wing...be reconsidered in this light. | Department of Zoology...scale with size and flight speed in birds Robert L. Nudds...

2004-01-01T23:59:59.000Z

244

Wind pro?le assessment for wind power purposes.  

E-Print Network [OSTI]

??Preliminary estimation of wind speed at the wind turbine hub height is critically important when planning new wind farms. Wind turbine power output is proportional… (more)

Sointu, Iida

2014-01-01T23:59:59.000Z

245

Sea Surface Roughness and Drag Coefficient as Functions of Neutral Wind Speed  

Science Journals Connector (OSTI)

Near the surface, it is commonly believed that the behavior of the (turbulent) atmospheric flow can be well described by a constant stress layer. In the case of a neutrally stratified surface layer, this leads to the well-known logarithmic wind ...

Hans Hersbach

2011-01-01T23:59:59.000Z

246

Energy Transfer via Solar Wind Driven Ultra Low Frequency Waves in the Earth's Magnetosphere  

E-Print Network [OSTI]

many pathways through which solar wind energy can drive wavemany pathways through which solar wind energy can drive wave

Hartinger, Michael David

2012-01-01T23:59:59.000Z

247

Measurable energy savings of installing variable frequency drives for cooling towers’ fans, compared to dual speed motors  

Science Journals Connector (OSTI)

Abstract In recent years the building management system (BMS) controllers have been used to control the operation of heating, ventilation, and air conditioning system in addition to lighting and some electrical equipment in order to save energy. In the water cooled system, the BMS controls the operation process of the cooling towers (CTs) fans of dual speed motors to maintain a constant leaving water temperature for different cooling loads and different ambient wet bulb temperature (WBT). This paper presents the effect of installing variable frequency drives (VFDs) for \\{CTs\\} fans in Kuwait during summer season on energy savings compared to dual speed control. The results have shown that with VFD mode, the reduction in water consumption was over 13% compared to the commonly used dual speed mode. More importantly, the combined power for the chillers and the \\{CTs\\} fans for the same amount of cooling produced were reduced by 5.8% in the VFD mode.

E. Al-Bassam; R. Alasseri

2013-01-01T23:59:59.000Z

248

Application of Ensemble Sensitivity Analysis to Observation Targeting for Short-term Wind Speed Forecasting  

SciTech Connect (OSTI)

The operators of electrical grids, sometimes referred to as Balancing Authorities (BA), typically make critical decisions on how to most reliably and economically balance electrical load and generation in time frames ranging from a few minutes to six hours ahead. At higher levels of wind power generation, there is an increasing need to improve the accuracy of 0- to 6-hour ahead wind power forecasts. Forecasts on this time scale have typically been strongly dependent on short-term trends indicated by the time series of power production and meteorological data from a wind farm. Additional input information is often available from the output of Numerical Weather Prediction (NWP) models and occasionally from off-site meteorological towers in the region surrounding the wind generation facility. A widely proposed approach to improve short-term forecasts is the deployment of off-site meteorological towers at locations upstream from the wind generation facility in order to sense approaching wind perturbations. While conceptually appealing, it turns out that, in practice, it is often very difficult to derive significant benefit in forecast performance from this approach. The difficulty is rooted in the fact that the type, scale, and amplitude of the processes controlling wind variability at a site change from day to day if not from hour to hour. Thus, a location that provides some useful forecast information for one time may not be a useful predictor a few hours later. Indeed, some processes that cause significant changes in wind power production operate predominantly in the vertical direction and thus cannot be monitored by employing a network of sensors at off-site locations. Hence, it is very challenging to determine the type of sensors and deployment locations to get the most benefit for a specific short-term forecast application. Two tools recently developed in the meteorological research community have the potential to help determine the locations and parameters to measure in order to get the maximum positive impact on forecast performance for a particular site and short-term look-ahead period. Both tools rely on the use of NWP models to assess the sensitivity of a forecast for a particular location to measurements made at a prior time (i.e. the look-ahead period) at points surrounding the target location. The fundamental hypothesis is that points and variables with high sensitivity are good candidates for measurements since information at those points are likely to have the most impact on the forecast for the desired parameter, location and look-ahead period. One approach is called the adjoint method (Errico and Vukicevic, 1992; Errico, 1997) and the other newer approach is known as Ensemble Sensitivity Analysis (ESA; Ancell and Hakim 2007; Torn and Hakim 2008). Both approaches have been tested on large-scale atmospheric prediction problems (e.g. forecasting pressure or precipitation over a relatively large region 24 hours ahead) but neither has been applied to mesoscale space-time scales of winds or any other variables near the surface of the earth. A number of factors suggest that ESA is better suited for short-term wind forecasting applications. One of the most significant advantages of this approach is that it is not necessary to linearize the mathematical representation of the processes in the underlying atmospheric model as required by the adjoint approach. Such a linearization may be especially problematic for the application of short-term forecasting of boundary layer winds in complex terrain since non-linear shifts in the structure of boundary layer due to atmospheric stability changes are a critical part of the wind power production forecast problem. The specific objective of work described in this paper is to test the ESA as a tool to identify measurement locations and variables that have the greatest positive impact on the accuracy of wind forecasts in the 0- to 6-hour look-ahead periods for the wind generation area of California's Tehachapi Pass during the warm (high generation) season. The paper is organized

Zack, J; Natenberg, E; Young, S; Manobianco, J; Kamath, C

2010-02-21T23:59:59.000Z

249

Simulation of winds as seen by a rotating vertical axis wind turbine blade  

SciTech Connect (OSTI)

The objective of this report is to provide turbulent wind analyses relevant to the design and testing of Vertical Axis Wind Turbines (VAWT). A technique was developed for utilizing high-speed turbulence wind data from a line of seven anemometers at a single level to simulate the wind seen by a rotating VAWT blade. Twelve data cases, representing a range of wind speeds and stability classes, were selected from the large volume of data available from the Clayton, New Mexico, Vertical Plane Array (VPA) project. Simulations were run of the rotationally sampled wind speed relative to the earth, as well as the tangential and radial wind speeds, which are relative to the rotating wind turbine blade. Spectral analysis is used to compare and assess wind simulations from the different wind regimes, as well as from alternate wind measurement techniques. The variance in the wind speed at frequencies at or above the blade rotation rate is computed for all cases, and is used to quantitatively compare the VAWT simulations with Horizontal Axis Wind Turbine (HAWT) simulations. Qualitative comparisons are also made with direct wind measurements from a VAWT blade.

George, R.L.

1984-02-01T23:59:59.000Z

250

MAPping Foehn Winds in the Austrian Alps  

E-Print Network [OSTI]

and the flow above mountain-top level 3. Study the vertical and cross-gap distribution of wind speed-valley horizontal wind speed ("measured") vertical wind speed (calculated) total wind speed & streamlines -20 -10 0 October 1999 ­ TEACO2 calculated 2D winds down-valley horizontal wind speed ("measured") vertical wind

Gohm, Alexander

251

Wind-speed inversion from HF radar first-order backscatter signal  

Science Journals Connector (OSTI)

Land-based high-frequency (HF) radars have the unique capability of continuously monitoring ocean surface environments at ranges up to 200 km off the coast. They provide reliable data on ocean surface currents an...

Wei Shen; Klaus-Werner Gurgel; George Voulgaris; Thomas Schlick…

2012-01-01T23:59:59.000Z

252

The Effect of Magnetic Field Tilt and Divergence on the Mass Flux and Flow Speed in a Line-Driven Stellar Wind  

E-Print Network [OSTI]

We carry out an extended analytic study of how the tilt and faster-than-radial expansion from a magnetic field affect the mass flux and flow speed of a line-driven stellar wind. A key motivation is to reconcile results of numerical MHD simulations with previous analyses that had predicted non-spherical expansion would lead to a strong speed enhancement. By including finite-disk correction effects, a dynamically more consistent form for the non-spherical expansion, and a moderate value of the line-driving power index $\\alpha$, we infer more modest speed enhancements that are in good quantitative agreement with MHD simulations, and also are more consistent with observational results. Our analysis also explains simulation results that show the latitudinal variation of the surface mass flux scales with the square of the cosine of the local tilt angle between the magnetic field and the radial direction. Finally, we present a perturbation analysis of the effects of a finite gas pressure on the wind mass loss rate and flow speed in both spherical and magnetic wind models, showing that these scale with the ratio of the sound speed to surface escape speed, $a/v_{esc}$, and are typically 10-20% compared to an idealized, zero-gas-pressure model.

Stan Owocki; Asif ud-Doula

2003-10-07T23:59:59.000Z

253

A method of micrositing of wind turbine on building roof-top by using joint distribution of wind speed and direction, and computational fluid dynamics  

Science Journals Connector (OSTI)

Urban wind turbines are recommended for installation on a building roof-top to capture more wind energy. It is critical to decide an exact location for the wind turbine installation on the roof-top area. ... this...

Bavuudorj Ovgor; Sang-Kwon Lee…

2012-12-01T23:59:59.000Z

254

Comparison of new hybrid FEEMD-MLP, FEEMD-ANFIS, Wavelet Packet-MLP and Wavelet Packet-ANFIS for wind speed predictions  

Science Journals Connector (OSTI)

Abstract The technology of wind speed prediction is important to guarantee the safety of wind power utilization. Compared to the single algorithms, the hybrid ones always have better performance in the wind speed predictions. In this paper, three most important decomposing algorithms [Wavelet Decomposition – WD/Wavelet Packet Decomposition – WPD/Empirical Mode Decomposition – EMD] and a latest decomposing algorithm [Fast Ensemble Empirical Mode Decomposition – FEEMD] are all adopted to realize the wind speed high-precision predictions with two representative networks [MLP Neural Network/ANFIS Neural Network]. Based on the hybrid forecasting framework, two new wind speed forecasting methods [FEEMD-MLP and FEEMD-ANFIS] are proposed. Additionally, a series of performance comparison is provided, which includes EMD-MLP, FEEMD-MLP, EDM-ANFIS, FEEMD-ANFIS, WD-MLP, WD-ANFIS, WPD-MLP and WPD-ANFIS. The aim of the study is to investigate the decomposing and forecasting performance of the different hybrid models. Two experimental results show that: (1) Due to the inclusion of the decomposing algorithms, the hybrid ANN algorithms have better performance than their corresponding single ANN algorithms; (2) the proposed new FEEMD-MLP hybrid model has the best performance in the three-step predictions while the WPD-MLP hybrid model has the best performance in the one-step predictions; (3) among the decomposing algorithms, the FEEMD and WPD have better performance than the EMD and WD, respectively; (4) in the forecasting neural networks, the MLP has better performance than the ANFIS; and (5) all of the proposed hybrid algorithms are suitable for the wind speed predictions.

Hui Liu; Hong-qi Tian; Yan-fei Li

2015-01-01T23:59:59.000Z

255

Structure of Turbulence in Katabatic Flows below and above the Wind-Speed Maximum  

E-Print Network [OSTI]

Measurements of small-scale turbulence made over the complex-terrain atmospheric boundary layer during the MATERHORN Program are used to describe the structure of turbulence in katabatic flows. Turbulent and mean meteorological data were continuously measured at multiple levels at four towers deployed along the East lower slope (2-4 deg) of Granite Mountain. The multi-level observations made during a 30-day long MATERHORN-Fall field campaign in September-October 2012 allowed studying of temporal and spatial structure of katabatic flows in detail, and herein we report turbulence and their variations in katabatic winds. Observed vertical profiles show steep gradients near the surface, but in the layer above the slope jet the vertical variability is smaller. It is found that the vertical (normal to the slope) momentum flux and horizontal (along the slope) heat flux in a slope-following coordinate system change their sign below and above the wind maximum of a katabatic flow. The vertical momentum flux is directed...

Grachev, Andrey A; Di Sabatino, Silvana; Fernando, Harindra J S; Pardyjak, Eric R; Fairall, Christopher W

2015-01-01T23:59:59.000Z

256

Wind-Induced Instability of Structures [and Discussion  

Science Journals Connector (OSTI)

13 May 1971 research-article Wind-Induced Instability of Structures [and...G. V. Parkinson D. Dicker Forms of wind-induced instability of structures are...structural response frequency over a discrete wind speed range and amplification and phase...

1971-01-01T23:59:59.000Z

257

Energy Transfer via Solar Wind Driven Ultra Low Frequency Waves in the Earth's Magnetosphere  

E-Print Network [OSTI]

on how various energy sources from the solar wind ultimatelymodes. The solar wind is an important energy source for ULFmodes. The solar wind is an important energy source for ULF

Hartinger, Michael David

2012-01-01T23:59:59.000Z

258

Encoding, application and association of radio frequency identification tags on high speed manufacturing lines  

E-Print Network [OSTI]

One of the entry points of radio frequency identification technology in supply chain applications is at the manufacturing line, after production, as packaged goods leave for the next link of the network of suppliers, ...

Fonseca, Herbert Moreti, 1973-

2004-01-01T23:59:59.000Z

259

Estimated global ocean wind power potential from QuikSCAT observations, accounting for turbine characteristics and siting  

E-Print Network [OSTI]

observations, vertical wind speed profile estimation giventhe wind speed profile is reduced, increasing vertical windvertical wind shear with respect to surface layer stability. Wind speeds

Capps, Scott B; Zender, Charles S

2010-01-01T23:59:59.000Z

260

Participation of wind power plants in system frequency control: Review of grid code requirements and control methods  

Science Journals Connector (OSTI)

Abstract Active power reserves are needed for the proper operation of an electrical system. These reserves are continuously regulated in order to match the generation and consumption in the system and thus, to maintain a constant electrical frequency. They are usually provided by synchronized conventional generating units such as hydraulic or thermal power plants. With the progressive displacement of these generating plants by non-synchronized renewable-based power plants (e.g. wind and solar) the net level of synchronous power reserves in the system becomes reduced. Therefore, wind power plants are required, according to some European Grid Codes, to also provide power reserves like conventional generating units do. This paper focuses not only on the review of the requirements set by Grid Codes, but also on control methods of wind turbines for their participation in primary frequency control and synthetic inertia.

Francisco Díaz-González; Melanie Hau; Andreas Sumper; Oriol Gomis-Bellmunt

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Effects of second-order difference-frequency wave forces on a new floating platform for an offshore wind turbine  

Science Journals Connector (OSTI)

This paper presents a study on an innovative floating platform for an offshore wind turbine operating at water depth of 50-80?m. The main focus is on hydrodynamic modelling of the floating platform with emphasis on the computation of second-order difference-frequency wave forces and their effects on the global rigid-body motion response. The time-domain analysis is conducted by coupling the wave analysis software WADAM of Det Norske Veritas and the aerodynamic code FAST of the National Renewable Energy Laboratory USA to consider the interaction between the wind turbine and floating platform. The numerical model accounts for aerodynamics control system of the wind turbine hydrodynamics and the mooring dynamics of the platform. Case studies with irregular waves and dynamic wind load are performed. A comparison of the results of different case studies is made to assess the influence of second-order wave forces on the motions of the floating platform.

A. Jiawen Li; B. Yougang Tang; C. Ronald W. Yeung

2014-01-01T23:59:59.000Z

262

Wind modelling based on wind input data conditions using Weibull distribution  

Science Journals Connector (OSTI)

Weibull distribution can be used to model the wind speed distribution at a particular site and hence, it can help in wind resource assessment (WRA) of a site. By calculating the shape (k) and scale (c) parameters for Weibull distribution, the wind speed frequency curve for a site can be made. Once this wind speed distribution for site is determined, it can be convolved with the power curve for a wind turbine and the annual energy output from the site can be determined. This paper presents how the Weibull distribution is used to determine the wind speed distribution for Vadravadra site in Gau Island of Fiji and how closely the annual energy output from the modelled wind speed distribution matches with the annual energy output using the actual wind speed distribution. It also presents how k is related to the turbulence intensity for a site; how the c is related to the annual mean wind speed and how a formula for estimating c is derived at a new height.

R.D. Prasad; R.C. Bansal; M. Sauturaga

2009-01-01T23:59:59.000Z

263

Definition: Wind rose | Open Energy Information  

Open Energy Info (EERE)

rose rose Jump to: navigation, search Dictionary.png Wind rose A diagram that shows the average percentage of time that the wind blows from different directions, typically on a monthly or annual basis.[1][2] View on Wikipedia Wikipedia Definition A wind rose is a graphic tool used by meteorologists to give a succinct view of how wind speed and direction are typically distributed at a particular location. Historically, wind roses were predecessors of the compass rose, as there was no differentiation between a cardinal direction and the wind which blew from such a direction. Using a polar coordinate system of gridding, the frequency of winds over a long time period are plotted by wind direction, with color bands showing wind ranges. The directions of the rose with the longest spoke show the wind direction with

264

Severe Limits on Variations of the Speed of Light with Frequency  

E-Print Network [OSTI]

Explosive astrophysical events at high red shift can be used to place severe limits on the fractional variation in the speed of light ($\\Delta c/c$), the photon mass ($m_{\\gamma}$), and the energy scale of quantum gravity ($E_{QG}$). I find $\\Delta c/c < 6.3 \\times 10^{-21}$ based on the simultaneous arrival of a flare in GRB 930229 with a rise time of $220 \\pm 30 \\mu s$ for photons of 30 keV and 200 keV. The limit on $m_{\\gamma}$ is $4.2 \\times 10^{-44} g$ for GRB 980703 from radio to gamma ray observations. The limit on $E_{QG}$ is $8.3 \\times 10^{16}$ GeV for GRB 930131 from 30 keV to 80 MeV photons.

Bradley E. Schaefer

1998-10-29T23:59:59.000Z

265

Blandford MTA Tower Wind Monitoring This document provides information not repeated in the monthly wind monitoring  

E-Print Network [OSTI]

on a regular basis. The logger samples wind speed and direction once every two seconds. These are then combined applicable): wind speed, wind speed standard deviation, wind direction, temperature, and solar insolation. F1 ranges applied for high and low wind speeds. A wind direction standard Blandford MTA Tower Wind

Massachusetts at Amherst, University of

266

Marion Meteorological Tower Wind Monitoring This document provides information not repeated in the monthly wind monitoring  

E-Print Network [OSTI]

. The logger samples wind speed and direction once every two seconds. These are then combined into 10-minute): wind speed, wind speed standard deviation, wind direction, temperature, and solar insolation. F1 > TF1 applied for high and low wind speeds. A wind direction standard Marion Met Tower Wind Monitoring #12

Massachusetts at Amherst, University of

267

A framework for estimating stratospheric wind speeds from unknown sources and application to the 2010 December 25 bolide  

Science Journals Connector (OSTI)

......provide group velocities (referred to...the Horizontal Wind Model (HWM)/Mass Spectrometer...measured trace velocity and celerity...measured trace velocity of the signal...Green 2012). Wind and temperature...Figure 1. Map of the Utah......

Stephen J. Arrowsmith; Omar Marcillo; Douglas P. Drob

2013-01-01T23:59:59.000Z

268

Low Wind Speed Technology Phase I: Evaluation of Design and Construction Approaches for Economical Hybrid Steel/Concrete Wind Turbine Towers; BERGER/ABAM Engineers Inc.  

SciTech Connect (OSTI)

This fact sheet describes a subcontract with BERGER/ABAM Engineers Inc. to study the economic feasibility of concrete and hybrid concrete/steel wind turbine towers.

Not Available

2006-03-01T23:59:59.000Z

269

Potential wind power generation in South Egypt  

Science Journals Connector (OSTI)

Egypt is one of the developing countries. The production of electricity in Egypt is basically on petroleum, natural gas, hydro-power and wind energy. The objective of this work to prove the availability of sufficient wind potential in the wide area of deep south Egypt for the operation of wind turbines there. Nevertheless, it gives in general an approximate profile which is useful to the wind parks design for this area. The data used in the calculation are published and analyzed for the first time. The diagrams of the measured wind data for three meteorological stations over a period of two years (wind speed, frequency, direction), wind shear coefficient, the mean monthly and annual wind speed profile for every location are presented. Monthly Weibull parameters, standard deviation and coefficient of variation have been statistically discussed. A comparison of the rose diagrams shows that the wind speed is more persistent and blow over this region of Egypt in two main sectors N and NNW with long duration of frequencies from 67% to 87% over the year with an average wind speed in the range 6.8–7.9 m/s at the three stations. Evaluation of monthly wind energy density at 10 m height by two different methods was carried out. And the final diagram for every site shows no significant difference between them. The annual natural wind energies at 70 m A.G.L. lie between 333 and 377 W/m2 for Dakhla South and Kharga stations, respectively, which is similar to the inland wind potential of Vindeby (Denmark) and some European countries. These results indicate that Kharga and Dakhla South locations are new explored sites for future wind power generation projects.

Ahmed Shata Ahmed

2012-01-01T23:59:59.000Z

270

Power and Frequency Control as it Relates to Wind-Powered Generation  

E-Print Network [OSTI]

Wind-Powered Generation Examples are: The rough running bands of hydro turbines Loadings of coal burning steam plants at which coal mills

Lacommare, Kristina S H

2011-01-01T23:59:59.000Z

271

Incorporating DFIG-Based Wind Power Generator in Microgird Frequency Stabilization.  

E-Print Network [OSTI]

??Although wind power as a renewable energy is assumed to be an all-round advantageous source of energy, its intermittent nature can cause difficulties, especially in… (more)

Fakhari Moghadam Arani, Mohammadreza

2012-01-01T23:59:59.000Z

272

Solar–wind–magnetosphere–ionosphere interactions in the Earth's plasma environment  

Science Journals Connector (OSTI)

...the great diagnostic power of combined in situ...ionosphere|solar-wind interactions| 10...the great diagnostic power of combined in situ...ionosphere; solar-wind interactions 1. Introduction...depend on the solar-wind speed via the power in ultra-low-frequency...

2003-01-01T23:59:59.000Z

273

Employing two novel mechanical fault ride through controllers for keeping stability of fixed speed wind generation systems hosted by standalone micro-grid  

Science Journals Connector (OSTI)

Abstract This paper proposes and designs two novels Fault Ride Through (FRT) controllers for maintaining Fixed Speed Wind Generation system (FSWGs) stability during fault events. The first technique has been implemented by increasing the wind turbine blade pitch angle with maximum possible rate to reduce the mechanical extracted wind power and consequently suppress wind generation system acceleration. The second FRT technique has been verified by adapting gear ratio of wind generation system to run far from optimum maximum power point and help FRT process. Effectiveness of the two proposed FRT techniques has been proven by accurate simulation of the most severe disturbance conditions. Also, Results indicated that second technique gives faster response than the first one. Without employing any FRT technique, \\{FSWGs\\} cannot keep its stability and the standalone Micro-Grid (MG) transfers to the blackout mode. Implementation the two FRT techniques requires no additional hardware. Only, control algorithms need little modification to deal with fault event and help FRT process. This fact makes the two proposed FRT techniques are simple, practical and highly economical attractive.

Rashad M. Kamel

2014-01-01T23:59:59.000Z

274

Analysis of Alongwind Tall Building Response to Transient Nonstationary Winds  

E-Print Network [OSTI]

where the mean wind speed is characterized by a time-invariant vertical profile and a single time of time varying mean wind speed, mean wind speed vertical profile, and spatial correlation of wind flows in terms of its unique mean wind speed vertical profile, rapid time varying mean wind speed

Chen, Xinzhong

275

Space-time forecasting and evaluation of wind speed with statistical tests for comparing accuracy of spatial predictions  

E-Print Network [OSTI]

). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 11 Comparing the predictive distributions for the models when the TDD model produces the best forecast (top panel) and when the BST model produces the best forecast (bottom panel). The small vertical line on the x-axis of each plot represents... of wind to benefit humans is not a new concept. Historically, wind- mills have been used to pump water from wells or to grind grain for centuries. But fast- forwarding into the 21st century, ?windmills? are being used to generate electricity. Wind turbines...

Hering, Amanda S.

2010-10-12T23:59:59.000Z

276

A Climatological Study of Boundary Layer Wind Speed Using a Meso-?-Scale Higher-Order Closure Model  

Science Journals Connector (OSTI)

A mesoscale higher-order closure atmospheric boundary layer model has been used to get more detailed information than is possible from observations regarding horizontal and vertical variations of the wind in an area in southeastern Sweden. To ...

Hans Bergström

1996-08-01T23:59:59.000Z

277

Technological Advances in Hydraulic Drive Trains for Wind Turbines  

Science Journals Connector (OSTI)

The reliability of frequency converters is a major concern for wind turbines. ChapDrive AS has built and tested a hydraulic drive train for variable speed wind turbines which includes a synchronous generator that is connected to the grid without the use of a frequency converter. The hydraulic drive train consists of a hydraulic pump, a variable displacement hydraulic motor, and a synchronous generator, which enables rotor speed control while maintaining synchronous speed of the generator. It has been proven that the hydraulic drive train and the ChapDrive Control system are able to absorb fluctuations in the wind speed and maintain a constant power output without the use of frequency converters. The hydraulic drive train and the ChapDrive Control system has been modeled analytically and compared to measurements, demonstrating a good agreement between simulations and measurements.

K.E.Thomsen; O.G. Dahlhaug; M.O.K. Niss; S.K. Haugset

2012-01-01T23:59:59.000Z

278

Modelling and control of a variable speed wind turbine driving doubly fed induction generator using three-level PWM converter  

Science Journals Connector (OSTI)

The aim of this researcher is to develop a complete wind central model driven doubly fed induction generator (DFIG) which feeds an AC power grid. For that, two-pulse width modulated (PWM) voltage converters are connected back to back between the rotor terminals of DFIG and the utility grid via a common DC link, in there, our contribution will appear in the utilisation of three levels voltage inverters in order to ameliorate the energy quality. The simulation was carried out on a 2 MW wind-turbine driven DFIG system and the developed unified model validity and the proposed control strategies feasibility are all confirmed by the simulated results.

Fairouz Kendouli; Khoudir Abed; Khalil Nabti; Hocine Benalla

2012-01-01T23:59:59.000Z

279

On the Heating of the Solar Corona and the Acceleration of the Low-Speed Solar Wind by Acoustic Waves Generated in Corona  

E-Print Network [OSTI]

We investigate possibilities of solar coronal heating by acoustic waves generated not at the photosphere but in the corona, aiming at heating in the mid- to low-latitude corona where the low-speed wind is expected to come from. Acoustic waves of period tau ~ 100s are triggered by chromospheric reconnection, one model of small scale magnetic reconnection events recently proposed by Sturrock. These waves having a finite amplitude eventually form shocks to shape sawtooth waves (N-waves), and directly heat the surrounding corona by dissipation of their wave energy. Outward propagation of the N-waves is treated based on the weak shock theory, so that the heating rate can be evaluated consistently with physical properties of the background coronal plasma without setting a dissipation length in an ad hoc manner. We construct coronal structures from the upper chromosphere to the outside of 1AU for various inputs of the acoustic waves having a range of energy flux of F_{w,0} = (1-20) times 10^5 erg cm^{-2} s^{-1} and a period of tau = 60-300s. The heating by the N-wave dissipation effectively works in the inner corona and we find that the waves of F_{w,0} >= 2 times 10^5 erg cm^{-2} s^{-1} and tau >= 60s could maintain peak coronal temperature, T_{max} > 10^6 K. The model could also reproduce the density profile observed in the streamer region. However, due to its short dissipation length, the location of T_{max} is closer to the surface than the observation, and the resultant flow velocity of the solar wind is lower than the observed profile of the low-speed wind. The cooperations with other heating and acceleration sources with the larger dissipation length are inevitable to reproduce the real solar corona.

Takeru Ken Suzuki

2002-06-14T23:59:59.000Z

280

The InterHourly-Variability (IHV) Index of Geomagnetic Activity and its Use in Deriving the Long-term Variation of Solar Wind Speed  

E-Print Network [OSTI]

We describe the derivation of the InterHourly Variability (IHV) index of geomagnetic activity. The IHV-index for a geomagnetic element is mechanically derived from hourly values as the sum of the unsigned differences between adjacent hours over a seven-hour interval centered on local midnight. The index is derived separately for stations in both hemispheres within six longitude sectors using only local night hours. It is intended as a long-term index. Available data allows derivation of the index back well into the 19th century. On a time scale of a 27-day Bartels rotation, IHV averages for stations with corrected geomagnetic latitude less than 55 degrees are strongly correlated with midlatitude range indices. Assuming a constant calibration of the aa-index we find that observed yearly values of aa before the year 1957 are 2.9 nT too small compared to values calculated from IHV using the regression constants based on 1980-2004. We interpret this discrepancy as an indication that the calibration of the aa index is in error before 1957. There is no such problem with the ap index. Rotation averages of IHV are also strongly correlated with solar wind parameters (BV^2). On a time scale of a year combining the IHV-index and the recently-developed Inter-Diurnal Variability (IDV) index (giving B) allows determination of solar wind speed, V, from 1890-present. Over the ~120-year series, the yearly mean solar wind speed varied from a low of 303 km/s in 1902 to a high value of 545 km/s in 2003. The calculated yearly values of the product BV using B and V separately derived from IDV and IHV agree quantitatively with (completely independent) BV derived from the amplitude of the diurnal variation of the H component in the polar caps since 1926 and sporadically beyond.

Leif Svalgaard; Edward W. Cliver

2007-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

WIND/RAIN BACKSCATTER MODELING AND WIND/RAIN RETRIEVAL FOR SCATTEROMETER AND  

E-Print Network [OSTI]

/rain backscatter model is developed that has inputs of surface rain rate, incidence angle, wind speed, wind from rain causes estimated wind speeds to be biased high and estimated wind directions to be biased directions are used as the wind direction estimate and the wind speed is derived from SAR by inversion

Long, David G.

282

Technology Improvement Opportunities for Low Wind Speed Turbines and Implications for Cost of Energy Reduction: July 9, 2005 - July 8, 2006  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Technology Improvement Technology Improvement Opportunities for Low Wind Speed Turbines and Implications for Cost of Energy Reduction July 9, 2005 - July 8, 2006 J. Cohen and T. Schweizer Princeton Energy Resources International (PERI) Rockville, Maryland A. Laxson, S. Butterfield, S. Schreck, and L. Fingersh National Renewable Energy Laboratory Golden, Colorado P. Veers and T. Ashwill Sandia National Laboratories Albuquerque, New Mexico Technical Report NREL/TP-500-41036 February 2008 NREL is operated by Midwest Research Institute â—Ź Battelle Contract No. DE-AC36-99-GO10337 National Renewable Energy Laboratory 1617 Cole Boulevard, Golden, Colorado 80401-3393 303-275-3000 * www.nrel.gov Operated for the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy

283

WP2 IEA Wind Task 26:The Past and Future Cost of Wind Energy  

E-Print Network [OSTI]

Energy Efficiency and Renewable Energy, Wind and HydropowerSpeed Sites. ” European Wind Energy Association. Marseille,Innovation and the price of wind energy in the US. ” Energy

Lantz, Eric

2014-01-01T23:59:59.000Z

284

WP2 IEA Wind Task 26:The Past and Future Cost of Wind Energy  

E-Print Network [OSTI]

Speed Sites. ” European Wind Energy Association. Marseille,Innovation and the price of wind energy in the US. ” EnergyThe Economics of Wind Energy. ” Renewable and Sustainable

Lantz, Eric

2014-01-01T23:59:59.000Z

285

Frequency control of a new topology in proton exchange membrane fuel cell/wind turbine/photovoltaic/ultra-capacitor/battery energy storage system based isolated networks by a novel intelligent controller  

Science Journals Connector (OSTI)

This paper proposes a new topology for hybrid isolated networks employing a wind turbine (WT) proton exchange membrane fuel cell (PEMFC) photovoltaic ultra-capacitor (UC) and battery energy storage system (BESS). The PEMFC is used in parallel with the UC and BESS; a configuration that improves the performance of the PEMFC in terms of dynamic response and lifetime. The proposed topology of the PEMFC along with a new model of WT reduces the initial costs of the hybrid isolated network. Due to power demand fluctuations in isolated networks to maintain the balance between power generation and consumption intelligent and flexible control methods must be applied. The variations of the solar irradiance of the wind speed and of the power consumption in hybrid isolated networks render the classic controllers and even fuzzy controllers inefficient. To overcome this problem we use a novel intelligent fuzzy controller which is optimized by the teaching-learning-based optimization method. In the structure of the new proposed controller the range and place of membership functions are optimized to reduce network frequency oscillations and improve network frequency stability. The designed control methodology is evaluated in the proposed isolated network and its performance is compared with the fuzzy controller proportional integral (PI) controller and optimal PI controller. To demonstrate the effectiveness of the proposed control strategies the above-mentioned detailed mathematical and dynamic models of the isolated network were integrated using MATLAB/Simulink.

2014-01-01T23:59:59.000Z

286

Perpendicular Ion Heating by Low-Frequency Alfven-Wave Turbulence in the Solar Wind  

E-Print Network [OSTI]

We consider ion heating by turbulent Alfven waves (AWs) and kinetic Alfven waves (KAWs) with perpendicular wavelengths comparable to the ion gyroradius and frequencies smaller than the ion cyclotron frequency. When the turbulence amplitude exceeds a certain threshold, an ion's orbit becomes chaotic. The ion then interacts stochastically with the time-varying electrostatic potential, and the ion's energy undergoes a random walk. Using phenomenological arguments, we derive an analytic expression for the rates at which different ion species are heated, which we test by simulating test particles interacting with a spectrum of randomly phased AWs and KAWs. We find that the stochastic heating rate depends sensitively on the quantity epsilon = dv/vperp, where vperp is the component of the ion velocity perpendicular to the background magnetic field B0, and dv (dB) is the rms amplitude of the velocity (magnetic-field) fluctuations at the gyroradius scale. In the case of thermal protons, when epsilon eps1, the proton ...

Chandran, Benjamin D G; Rogers, Barrett N; Quataert, Eliot; Germaschewski, Kai

2010-01-01T23:59:59.000Z

287

Constant Speed for Processing  

Science Journals Connector (OSTI)

Synduction motor combines constant speed of synchronous motor with ruggedness of induction motor ... CONVENTIONAL SYNCHRONOUS ELECTRIC MOTORS operate at constant speed, regardless of load and voltage—frequency is the determining factor. ...

1956-04-23T23:59:59.000Z

288

Geographical and seasonal variability of the global “practical” wind resources  

Science Journals Connector (OSTI)

Abstract This paper provides global and seasonal estimates of the “practical” wind power obtained with a 3-D numerical model (GATOR-GCMOM) that dynamically calculates the instantaneous wind power of a modern 5 MW wind turbine at 100-m hub height at each time step. “Practical” wind power is defined as that delivered from wind turbines in high-wind locations (year-average 100-m wind speed ? 7 m/s) over land and near-shore, excluding both polar regions, mountainous, and conflicting land use areas, and including transmission, distribution, and wind farm array losses. We found that seasonal variations in the global practical wind resources are significant. The highest net land plus near-shore capacity factors globally are found during December–January–February and the lowest during June–July–August. The capacity factors in the transitional seasons (March–April–May and September–October–November) are rather similar to one another in terms of geographical patterns and frequency distributions. The yearly-average distributions of capacity factors, whether in terms of geographic patterns or frequency distributions, differ from those in all four seasons, although they are closest to the transitional seasons. Regional practical wind resources are sensitive to seasons and to thresholds in year-average wind speed and bathymetry, but are more than enough to supply local electricity demand in all regions except Japan.

Cristina L. Archer; Mark Z. Jacobson

2013-01-01T23:59:59.000Z

289

Offshore Wind Potential Tables  

Wind Powering America (EERE)

Offshore wind resource by state and wind speed interval within 50 nm of shore. Wind Speed at 90 m (ms) 7.0 - 7.5 7.5 - 8.0 8.0 - 8.5 8.5 - 9.0 9.0 - 9.5 9.5 - 10.0 >10.0 Total...

290

Ris-PhD-Report Sensing the wind profile  

E-Print Network [OSTI]

for wind speed measurements performed at either sites. The wind speed measurements are averaged for several to scale the wind speed with the surface friction velocity, whereas at Horns Rev a new scaling is added deviate from the logarithmic wind prole, but agree better with the wind speed measurements. The length

291

Simulation of Short-term Wind Speed Forecast Errors using a Multi-variate ARMA(1,1) Time-series Model.  

E-Print Network [OSTI]

?? The short-term (1 to 48 hours) predictability of wind power production from wind power plants in a power system is critical to the value… (more)

Boone, Andrew

2005-01-01T23:59:59.000Z

292

An Improved Method for Estimating the Wind Power Density Distribution Function  

Science Journals Connector (OSTI)

The wind power density (WPD) distribution curve is essential for wind power assessment and wind turbine engineering. The usual practice of estimating this curve from wind speed data is to first estimate the wind speed probability density function ...

Mark L. Morrissey; Werner E. Cook; J. Scott Greene

2010-07-01T23:59:59.000Z

293

Dynamic Simulation Studies of the Frequency Response of the Three U.S. Interconnections with Increased Wind Generation  

E-Print Network [OSTI]

power to pump), large pumps associated with water conveyance, and interruptible loads and selected firm loads. Wind

Mackin, Peter

2011-01-01T23:59:59.000Z

294

Dynamic Simulation Studies of the Frequency Response of the Three U.S. Interconnections with Increased Wind Generation  

E-Print Network [OSTI]

wind turbine through a gearbox, and uses a conventional "squirrel cage" induction generator directly connected to the grid.

Mackin, Peter

2011-01-01T23:59:59.000Z

295

Potential of Establishment of Wind Farms in Western Province of Saudi Arabia  

Science Journals Connector (OSTI)

Abstract In the present study, the economic feasibility of development of 15 MW wind power plant (wind farm) at Taif, Western Province of the Kingdom of Saudi Arabia (K.S.A) has been investigated by analyzing long-term wind speed data. Western province has relatively better wind energy resources. Data analysis indicates that monthly average wind speeds of Taif (21 29’ N, 40 32’ E) range from 3.1 to 4.8 m/s at 10 m height. The wind farms simulated consist of different combinations of 600 kW commercial wind machines (50 m hub-height). NREL's (HOMER Energy's) HOMER software has been employed to perform the techno-economic assessment. The study presents monthly variations of wind speed, cumulative frequency distribution (CFD) profiles of wind speed, monthly and yearly amount of energy generated from the 15 MW wind farm (50 m hub-height), cost of generating energy (COE, $/kWh), capacity factor (%), etc. The CFD indicates that the wind speeds are less than 3 m/s for 46% of the time during the year. This implies that wind electric conversion systems (WECS) will not produce energy for about 46% of the time during the year. The annual energy produced by 15 MW wind farm (50 m hub-height) has been found to be 19939 MWh. The cost of wind-based electricity by using 600 kW (50m hub-height) commercial WECS has been found to be 0.0576 US$/kWh. With the development of 15 MW wind farm, about 453 tons/year of carbon emissions can be avoided entering into the local atmospheric. The paper also attempts to address various aspects (such as: effect of hub-height, etc.) of wind farm establishment

S.M. Shaahid; Luai M. Al-Hadhrami; M.K. Rahman

2014-01-01T23:59:59.000Z

296

Measurements of the source level of ambient noise due to wind  

Science Journals Connector (OSTI)

Measurements of the source level of wind?generated ambient noise in the deep ocean are presented for the frequency band 10–350 Hz. The data were obtained using a vertical line array deployed in the deep sound channel at various sites in the Northeast Pacific. The array response was steered vertically upward to measure the local sea surface noise and eliminate distant shipping noise. The beamforming was carried out in the frequency domain using a Kaiser?Bessel window to reduce sidelobe levels. The beam power levels obtained were referenced to a source level at the sea surface using a simple propagation model. The estimated wind noise levels N were fitted to the wind speed v at a specific frequency using a model of the form N = A + 20 n log v. The data indicate two we!l?defined regions with a weak wind?speed dependence at low wind speeds before wave breaking occurs and a stronger dependence at higher wind speeds. The values of n for wind speeds > 10 kn were in the range from 1.1–1.8. The source levels are compared with other measurements reported in the literature.

N. Ross Chapman; James W. Cornish

1990-01-01T23:59:59.000Z

297

New England Wind Forum: Wind Power Economics  

Wind Powering America (EERE)

State Activities Projects in New England Building Wind Energy in New England Wind Resource Wind Power Technology Economics Cost Components Determining Factors Influencing Wind Economics in New England How does wind compare to the cost of other electricity options? Markets Siting Policy Technical Challenges Issues Small Wind Large Wind Newsletter Perspectives Events Quick Links to States CT MA ME NH RI VT Bookmark and Share Wind Power Economics Long-Term Cost Trends Since the first major installations of commercial-scale wind turbines in the 1980s, the cost of energy from wind power projects has decreased substantially due to larger turbine generators, towers, and rotor lengths; scale economies associated with larger projects; improvements in manufacturing efficiency, and technological advances in turbine generator and blade design. These technological advances have allowed for higher generating capacities per turbine and more efficient capture of wind, especially at lower wind speeds.

298

Vertical axis wind turbine  

SciTech Connect (OSTI)

Wind turbines are largely divided into vertical axis wind turbines and propeller (Horizontal axis) wind turbines. The present invention discloses a vertical axis high speed wind turbine provided with rotational speed control systems. This vertical axis wind turbine is formed by having blades of a proper airfoil fitted to respective supporting arms provided radially from a vertical rotating shaft by keeping the blade span-wise direction in parallel with the shaft and being provided with aerodynamic control elements operating manually or automatically to control the rotational speed of the turbine.

Kato, Y.; Seki, K.; Shimizu, Y.

1981-01-27T23:59:59.000Z

299

ARM - Evaluation Product - Derived Wind Profiles from Doppler...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the radial velocity data; the amplitude, phase and offset of the sinusoid determine the wind speed, wind direction and vertical velocity, respectively. The derived winds are...

300

Zoning for Small Wind: The Importance of Tower Height  

Wind Powering America (EERE)

1 1 Zoning for Small Wind: The Importance of Tower Height An ASES Small Wind Webinar Mick Sagrillo-Wisconsin's Focus on Energy © 2008 by Mick Sagrillo 2 Definitions: rotor L&S Tech. Assoc., Inc. Rotor = "collector" for a wind system 3 Definitions: wind * Wind = the 'fuel' * Wind has two 'components' - Quantity = wind speed (velocity or V) - Quality = 'clean' flowing wind 4 Quantity * = average annual wind speed * Climate, not weather * Akin to annual average sun hours for PV or head and flow for hydro * Wind speed increases with height above ground... * ...Due to diminished ground drag (friction) 5 Power in the wind V³ * Wind speed = V * Power available is proportional to wind speed x wind speed x wind speed - or P ~ V x V x V - or P ~ V ³ * Therefore, 10% V = 33% P * Lesson !

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Assessment of wind and solar energy resources in Batna, Algeria  

Science Journals Connector (OSTI)

Due to several climate changes caused by greenhouse gas and to the increasing need for clean energies, scientists drew attention to renewable energy sources, which are the most suitable solution in the future. Sparsely populated and flat open terrains observed in Batna region (North East of Algeria) and its semi-arid climate, make it a promising region for the development of solar and wind energies. In this article, we analyzed ten years of daily wind speed data in a remote area of Batna: Mustafa Ben Boulaid Airport. Wind power availability, as well as annual mean values of wind speed and power, were estimated. Frequency distribution of daily totals of wind speed data were counted and illustrated too. The results have been used to estimate net energy output of different wind turbines. This simulation shows a difference in wind generators production and allows us to choose the best wind turbine adapted to site conditions. Since solar and wind energy resources may be used to compensate each other, we evaluated also the solar potential of the same area.

Mounir Aksas; Amor Gama

2011-01-01T23:59:59.000Z

302

Wind energy conversion system  

DOE Patents [OSTI]

The wind energy conversion system includes a wind machine having a propeller connected to a generator of electric power, the propeller rotating the generator in response to force of an incident wind. The generator converts the power of the wind to electric power for use by an electric load. Circuitry for varying the duty factor of the generator output power is connected between the generator and the load to thereby alter a loading of the generator and the propeller by the electric load. Wind speed is sensed electro-optically to provide data of wind speed upwind of the propeller, to thereby permit tip speed ratio circuitry to operate the power control circuitry and thereby optimize the tip speed ratio by varying the loading of the propeller. Accordingly, the efficiency of the wind energy conversion system is maximized.

Longrigg, Paul (Golden, CO)

1987-01-01T23:59:59.000Z

303

Technology Improvement Opportunities for Low Wind Speed Turbines and Implications for Cost of Energy Reduction: July 9, 2005 - July 8, 2006  

SciTech Connect (OSTI)

This report analyzes the status of wind energy technology in 2002 and describes the potential for technology advancements to reduce the cost and increase the performance of wind turbines.

Cohen, J.; Schweizer, T.; Laxson, A.; Butterfield, S.; Schreck, S.; Fingersh, L.; Veers, P.; Ashwill, T.

2008-02-01T23:59:59.000Z

304

Optimization of Wind Turbine Operation  

E-Print Network [OSTI]

inclination angle was about 1°. The spinner anemometer measurements were correlated with wind speed and windOptimization of Wind Turbine Operation by Use of Spinner Anemometer TF Pedersen, NN Sørensen, L Title: Optimization of Wind Turbine Operation by Use of Spinner Anemometer Department: Wind Energy

305

The Influence of Turbulence and Vertical Wind Profile in Wind Turbine Power Curve  

Science Journals Connector (OSTI)

To identify the influence of turbulence and vertical wind profile in wind turbine performance, wind speed measurements at different heights have been ... equipment, specifically a pulsed wave one. The wind profil...

A. Honrubia; A. Vigueras-Rodríguez…

2012-01-01T23:59:59.000Z

306

Hurricane wind fields needed to assess risk to offshore wind farms  

Science Journals Connector (OSTI)

...Scatterplot of maximum landfall winds at wind farm locations (y axis) compared with the peak life cycle wind speed for the same hurricane while...Quantifying the hurricane risk to offshore wind turbines . Proc Natl Acad Sci USA 109 : 3247...

Mark D. Powell; Steven Cocke

2012-01-01T23:59:59.000Z

307

Impacts of Providing Inertial Response on Dynamic Loads of Wind Turbine Drivetrains: Preprint  

SciTech Connect (OSTI)

There has been growing demand from the power industry for wind power plants to support power system operations. One such requirement is for wind turbines to provide ancillary services in the form of inertial response. When the grid frequency drops, it is essential for wind turbine generators (WTGs) to inject kinetic energy stored in their inertia into the grid to help arrest the frequency decline. However, the impacts of inertial response on the structural loads of the wind turbine have not been given much attention. To bridge this gap, this paper utilizes a holistic model for both fixed-speed and variable-speed WTGs by integrating the aeroelastic wind turbine model in FAST, developed by the National Renewable Energy Laboratory, with the electromechanical drivetrain model in SimDriveline and SimPowerSystems.

Girsang, I. P.; Dhupia, J.; Singh, M.; Gevorgian, V.; Muljadi, E.; Jonkman, J.

2014-09-01T23:59:59.000Z

308

Evaluation of wind turbine noise levels and impact studies  

Science Journals Connector (OSTI)

Measured A?weighted sound levels at 125?ft distance for individual wind turbines with 20? to 120?kW power ratings are typically in the range 65–75 dB at moderate to high power output conditions (20–30?mph wind speeds). Tonelike sounds in the 300? to 1000?Hz frequency range often are clearly audible. Cyclical fluctuations of 10 dB in low?frequency noise levels are propagated by some downwind?type turbines. The random aerodynamic rotor noisesounds like a roar the gear box noisesounds like a whine and the low?frequency noise fluctuations sound like “thump?thump” or “whoosh?whoosh.” All of these wind turbinenoises are propagated from existing wind farms to residential areas and are judged intrusive and annoying. Measurements and predictions of wind turbinenoise submitted with applications for wind farm development have often contained errors which understated the noise levels by 3–10 dB. These errors were due to noisemeasurements at minimal wind speeds and turbine power and faulty modeling procedures. Simple analytical expressions have been developed which quickly and accurately predict the noise levels for large turbine arrays.

Samuel R. Lane

1986-01-01T23:59:59.000Z

309

PHYSICAL REVIEW E 88, 042146 (2013) Uncovering wind turbine properties through two-dimensional stochastic modeling of wind dynamics  

E-Print Network [OSTI]

PHYSICAL REVIEW E 88, 042146 (2013) Uncovering wind turbine properties through two, such as the rated speed of the wind turbine or the descriptive wind speed statistics, can be related to the equations describing the evolution of power production and wind speed at single wind turbines. DOI: 10

Peinke, Joachim

310

On prediction of wind-borne plumes with simple models of turbulent transport  

E-Print Network [OSTI]

of x, and the vertical wind speed of gas above ground wass x 10 Vertical gas velocity, horizontal wind speed = 1 m/ss x 10 Vertical gas velocity, horizontal wind speed = 5 m/s

Schwarz, Katherine; Patzek, Tad; Silin, Dmitriy

2008-01-01T23:59:59.000Z

311

Wind energy conversion system  

SciTech Connect (OSTI)

This patent describes a wind energy conversion system comprising: a propeller rotatable by force of wind; a generator of electricity mechanically coupled to the propeller for converting power of the wind to electric power for use by an electric load; means coupled between the generator and the electric load for varying the electric power drawn by the electric load to alter the electric loading of the generator; means for electro-optically sensing the speed of the wind at a location upwind from the propeller; and means coupled between the sensing means and the power varying means for operating the power varying means to adjust the electric load of the generator in accordance with a sensed value of wind speed to thereby obtain a desired ratio of wind speed to the speed of a tip of a blade of the propeller.

Longrigg, P.

1987-03-17T23:59:59.000Z

312

NREL: Wind Research - NREL's Wind Technology Patents Boost Efficiency and  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

NREL's Wind Technology Patents Boost Efficiency and Lower Costs NREL's Wind Technology Patents Boost Efficiency and Lower Costs March 22, 2013 Wind energy research conducted at the National Wind Technology Center (NWTC) at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) during the last decade has earned the lab two patents, one for adaptive pitch control and one for a resonance blade test system that will ultimately help its industry partners increase the efficiency of wind technologies and reduce the cost of wind energy. The most recent patent for adaptive pitch control for variable-speed wind turbines was granted in May 2012. Variable-speed wind turbines use rotor blade pitch control to regulate rotor speed at the high wind speed limit. Although manufacturers and operators have been interested in developing a nominal pitch to improve

313

Doppler Lidar–Based Wind-Profile Measurement System for Offshore Wind-Energy and Other Marine Boundary Layer Applications  

Science Journals Connector (OSTI)

Accurate measurement of wind speed profiles aloft in the marine boundary layer is a difficult challenge. The development of offshore wind energy requires accurate information on wind speeds above the surface at least at the levels occupied by ...

Yelena L. Pichugina; Robert M. Banta; W. Alan Brewer; Scott P. Sandberg; R. Michael Hardesty

2012-02-01T23:59:59.000Z

314

Vertical axis wind turbine  

SciTech Connect (OSTI)

Wind turbines are largely divided into vertical axis wind turbines and propeller (Horizontal axis) wind turbines. The present invention discloses a vertical axis high speed wind turbine provided with a starting and braking control system. This vertical axis wind turbine is formed by having blades of a proper airfoil fitted to respective supporting arms provided radially from a vertical rotary axis by keeping the blade span-wise direction in parallel with the axis and being provided with a low speed control windmill in which the radial position of each operating piece varies with a centrifugal force produced by the rotation of the vertical rotary axis.

Kato, Y.; Seki, K.; Shimizu, Y.

1981-01-27T23:59:59.000Z

315

White lighting LEDs are fast replacing conventional lighting because not only are they energy efficient light sources but also can be modulated at frequencies up to 20MHz for high-speed wireless communication, especially for indoor applications.  

E-Print Network [OSTI]

are they energy efficient light sources but also can be modulated at frequencies up to 20MHz for high-speedBackground White lighting LEDs are fast replacing conventional lighting because not only wireless communication, especially for indoor applications. Moreover, using visible light as the source

Sekercioglu, Y. Ahmet

316

Definition: Wind power | Open Energy Information  

Open Energy Info (EERE)

Wind power Wind power Jump to: navigation, search Dictionary.png Wind power The amount of power available to a wind turbine depends on: air density, wind speed and the swept area of the rotor. While the power is proportional to air density and swept area, it varies with the cube of wind speed, so small changes in wind speed can have a relatively large impact on wind power.[1] View on Wikipedia Wikipedia Definition Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electrical power, windmills for mechanical power, windpumps for water pumping or drainage, or sails to propel ships. Large wind farms consist of hundreds of individual wind turbines which are connected to the electric power transmission network. Offshore wind is steadier and stronger than on land, and offshore farms

317

Global potential for wind-generated electricity  

Science Journals Connector (OSTI)

...6 MW, deployed offshore, reflecting the greater...incentive to deploy larger turbines to capture the higher wind speeds available in...Electricity-Producing Wind Turbines ( International Electrotechnical...2008 ) Assessing offshore wind resources: An accessible...

Xi Lu; Michael B. McElroy; Juha Kiviluoma

2009-01-01T23:59:59.000Z

318

Breaking wind waves as a source of ambient noise  

Science Journals Connector (OSTI)

A theoretical model for the prediction of ambient noise level due to collective oscillations of air bubbles under breaking wind waves is presented. The model uses a budget of the energy flux from the breaking waves to quantify acoustic power radiation by a bubble cloud. A shift of the noise spectra to lower frequency due to collective bubble oscillation is assumed. The model derives good estimates of the magnitude slope and frequency range of the noise spectra using the wind speed or height of breaking waves.

Pavlo Tkalich; Eng Soon Chan

2002-01-01T23:59:59.000Z

319

WIND ENERGY Wind Energ. 2013; 00:112  

E-Print Network [OSTI]

WIND ENERGY Wind Energ. 2013; 00:1­12 DOI: 10.1002/we RESEARCH ARTICLE Model predictive control in wind speed, ensuring certain power gradients, with an insignificant loss in energy production rejection, model predictive control, convex optimization, wind power control, energy storage, power output

320

Wind Technology Advancements and Impacts on Western Wind Resources (Presentation)  

SciTech Connect (OSTI)

Robi Robichaud made this presentation at the Bureau of Land Management West-wide Wind Opportunities and Constraints Mapping (WWOCM) Project public meeting in Denver, Colorado in September 2014. This presentation outlines recent wind technology advancements, evolving turbine technologies, and industry challenges. The presentation includes maps of mean wind speeds at 50-m, 80-m, and 100-m hub heights on BLM lands. Robichaud also presented on the difference in mean wind speeds from 80m to 100m in Wyoming.

Robichaud, R.

2014-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

National Wind Technology Center (Fact Sheet), National Wind Technology...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

hydrokinetic (MHK) energy devices are high-force, low-speed machines, similar to wind turbines that convert the kinetic energy of a moving fluid into electrical energy....

322

Performance of PI controller for control of active and reactive power in DFIG operating in a grid-connected variable speed wind energy conversion system  

Science Journals Connector (OSTI)

Due to several factors, wind energy becomes an essential type of electricity generation. The share of this type of energy in the network is becoming increasingly important. The objective of this work is to presen...

Azzouz Tamaarat; Abdelhamid Benakcha

2014-09-01T23:59:59.000Z

323

RIS0-M-2432 SIMPLIFIED LAWS OF SIMIALRITY FOR WIND TURBINE ROTORS  

E-Print Network [OSTI]

comments are presented on comparison of stall-and pitch-regu- lated wind turbines and on two speed Shape factor (Weibull) Rotational speed Power Rotor radius Wind speed Rotor tip speed Tip speed ratio V is the wind speed at hub height, j> is the air density, #12;0 . 5 u ·p C

324

Wind Gallery | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

(shown here), concrete, or steel lattice. Supports the structure of the turbine. Because wind speed increases with height, taller towers enable turbines to capture more energy and...

325

NREL: Wind Research - Offshore Wind Resource Characterization  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Offshore Wind Resource Characterization Offshore Wind Resource Characterization Map of the United States, showing the wind potential of offshore areas across the country. Enlarge image US offshore wind speed estimates at 90-m height NREL scientists and engineers are leading efforts in resource mapping, remote sensor measurement and development, and forecasting that are essential for the development of offshore wind. Resource Mapping For more than 15 years, NREL's meteorologists, engineers, and Geographic Information System experts have led the production of wind resource characterization maps and reports used by policy makers, private industry, and other government organizations to inform and accelerate the development of wind energy in the United States. Offshore wind resource data and mapping has strategic uses. As with terrestrial developments, traditional

326

Synoptic and local influences on boundary layer processes, with an application to California wind power  

E-Print Network [OSTI]

corresponding to extreme winds for di?erent stations andin turn would lead to extreme downscaled wind speed changeextreme quintiles or more exacting classi?cations of wind

Mansbach, David K.

2010-01-01T23:59:59.000Z

327

Wind Power | Open Energy Information  

Open Energy Info (EERE)

Wind Power Wind Power Jump to: navigation, search Wind Power WIndfarm.Sunset.jpg Wind power is a form of solar energy.[1] Wind is caused by the uneven heating of the atmosphere by the sun, variations in the earth's surface, and rotation of the earth. Mountains, bodies of water, and vegetation all influence wind flow patterns[2], [3]. Wind energy (or wind power) describes the process by which wind is used to generate electricity. Wind turbines convert the energy in wind to electricity by rotating propeller-like blades around a rotor. The rotor turns the drive shaft, which turns an electric generator.[2] Three key factors affect the amount of energy a turbine can harness from the wind: wind speed, air density, and swept area.[4] Mechanical power can also be utilized directly for specific tasks such as

328

Analysis of Temporal and Spatial Characteristics on Output of Wind Farms with Doubly Fed Induction Generator Wind Turbines  

Science Journals Connector (OSTI)

Due to the large number of wind turbines and covering too large area in a large wind farm, wake effects among wind turbines and wind speed time delays will have a greater impact of wind farms models. Taking wind farms with doubly fed induction generator(DFIG) ... Keywords: wind farm, modeling, temporal and spatial characteristics, DFIG, output characteristics

Shupo Bu; Xunwen Su

2012-12-01T23:59:59.000Z

329

Modeling of wind farm controllers Poul Srensen1  

E-Print Network [OSTI]

and dead band. Two types of wind farms are presented. The first using variable speed wind turbines with doubly fed induction generators and fixed speed wind turbines with active stall control. Keywords: wind the wind turbines have increased in size, the costs have been reduced, and the controllability developed

330

Evaluation of wind energy potential and electricity generation at five locations in Jordan  

Science Journals Connector (OSTI)

Abstract Evaluation of the wind power from the knowledge of the mean monthly wind speeds of a typical year, and for five different locations in Jordan is analyzed and assessed. In addition, an investigation into the feasibility of using five different wind turbines of different rated power ranging from 100 kW to 3000 kW at each location to be employed in wind farms is examined. The data of the wind speeds over five years are fitted to the Weibull distribution, which is most frequently used and most appropriate, describing frequency distribution for wind moving over Jordan. The annual mean values of the wind speed and the frequency distributions were found for the five locations studied; Ras-Moneef, Azraq south; Safawi, Queen Alia Airport and Aqaba Airport. The locations included the eastern desert regions where wide plain lands are economically feasible to be used for wind farms. It is apparent from the results of the analysis that the highly promising sites of having good wind energy potential are Aqaba and Ras-Moneef, whereas, the desert sites of Safawi and Azraq South have only moderate potential and Queen Alia Airport have a lower potential. The annual mean values of the wind speed and power density of the observed and theoretical distributions are 5.5 ms?1 and 160 Wm?2 for Ras Moneef, 4.0 ms?1 and 175 Wm?2 for Azraq South, 4.5 ms?1 and 94 Wm?2 for Safawi, 3.13 ms?1 and 31 Wm?2 for Queen Alia Airport and 6.0 ms?1 and 215 Wm?2 for Aqaba Airport, respectively.

Handri D. Ammari; Saad S. Al-Rwashdeh; Mohammad I. Al-Najideen

2014-01-01T23:59:59.000Z

331

Structural responses and power output of a wind turbine are strongly affected by the wind field acting on the wind turbine. Knowledge about the wind field and its  

E-Print Network [OSTI]

ABSTRACT Structural responses and power output of a wind turbine are strongly affected by the wind affect the power output and structural responses of a wind turbine. Wind field characteristics are conventionally described by time averaged features, such as mean wind speed, turbulence intensity and power

Stanford University

332

Adjustable Speed Drive Part-Load Efficiency  

Broader source: Energy.gov [DOE]

An adjustable speed drive (ASD) is a device that controls the rotational speed of motor-driven equipment. Variable frequency drives (VFDs), the most common type of ASDs, efficiently meet varying process requirements by adjusting the frequency and voltage of the power supplied to an AC motor to enable it to operate over a wide speed range. External sensors monitor flow, liquid levels, or pressure and then transmit a signal to a controller that adjusts the frequency and speed to match process requirements.

333

Wind Resource Assessment of Gujarat (India)  

SciTech Connect (OSTI)

India is one of the largest wind energy markets in the world. In 1986 Gujarat was the first Indian state to install a wind power project. In February 2013, the installed wind capacity in Gujarat was 3,093 MW. Due to the uncertainty around existing wind energy assessments in India, this analysis uses the Weather Research and Forecasting (WRF) model to simulate the wind at current hub heights for one year to provide more precise estimates of wind resources in Gujarat. The WRF model allows for accurate simulations of winds near the surface and at heights important for wind energy purposes. While previous resource assessments published wind power density, we focus on average wind speeds, which can be converted to wind power densities by the user with methods of their choice. The wind resource estimates in this study show regions with average annual wind speeds of more than 8 m/s.

Draxl, C.; Purkayastha, A.; Parker, Z.

2014-07-01T23:59:59.000Z

334

Synoptic and local influences on boundary layer processes, with an application to California wind power  

E-Print Network [OSTI]

th percentiles of daily wind speeds (vertical axis) largelyand warm SST. Mean vertical pro?les of wind speed from EPICspeed at the wind farm sites, since inversion strength is largely controlled by the vertical

Mansbach, David K.

2010-01-01T23:59:59.000Z

335

Operational behavior of a double-fed permanent magnet generator for wind turbines  

E-Print Network [OSTI]

Greater efficiency in wind turbine systems is achieved by allowing the rotor to change its rate of rotation as the wind speed changes. The wind turbine system is decoupled from the utility grid and a variable speed operation ...

Reddy, Sivananda Kumjula

2005-01-01T23:59:59.000Z

336

Wind Turbine Blade Design  

K-12 Energy Lesson Plans and Activities Web site (EERE)

Blade engineering and design is one of the most complicated and important aspects of modern wind turbine technology. Engineers strive to design blades that extract as much energy from the wind as possible throughout a range of wind speeds and gusts, yet are still durable, quiet and cheap. A variety of ideas for building turbines and teacher handouts are included in this document and at the Web site.

337

Ris R 1068EN Extreme Winds  

E-Print Network [OSTI]

Ris R 1068EN Extreme Winds in Denmark Leif Kristensen and Ole Rathmann Ris National Laboratory of this investigationis to study, on basis of climatologicalrecords, how large extreme wind speeds are in various parts;Abstract Wind-speed data from four sites in Denmark have been analyzed in order to obtain estimates

338

High-Order Sliding Mode Control of DFIG-Based Wind Turbines  

Science Journals Connector (OSTI)

Actually, variable speed wind turbines are continuously increasing their market share, since it is possible to track the changes in wind speed by adapting shaft speed, and thus maintaining optimal power genera...

Mohamed Benbouzid

2014-01-01T23:59:59.000Z

339

Dynamic valuation model For wind development in regard to land value, proximity to transmission lines, and capacity factor  

E-Print Network [OSTI]

Developing a wind farm involves many variables that can make or break the success of a potential wind farm project. Some variables such as wind data (capacity factor, wind rose, wind speed, etc.) are readily available in ...

Nikandrou, Paul

2009-01-01T23:59:59.000Z

340

Models for Assessing Power Fluctuations from Large Wind Farms N. A. Cutululis1)  

E-Print Network [OSTI]

typical and worst case power fluctuations using the geographical sitting of wind turbines as an input comprehensive, with one year of wind speeds and power from all individual wind turbines in the wind farms of the fluctuating nature of wind speeds, the increasing use of wind turbines for power generation has caused more

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Wind News | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Wind News Wind News Wind News RSS February 7, 2011 Salazar, Chu Announce Major Offshore Wind Initiatives Strategic plan, $50 million in R&D funding, identified Wind Energy Areas will speed offshore wind energy development December 16, 2010 Department of Energy Finalizes Loan Guarantee to Support World's Largest Wind Project 845-Megawatt Wind Facility Will Create Hundreds of Jobs and Avoid Over 1.2 Million Tons of Carbon Dioxide Annually October 29, 2010 Statement by Energy Secretary Steven Chu on Today's Grand Opening of the Nordex Manufacturing Facility in Jonesboro, Arkansas Recovery Act investment creates jobs, helps lay the foundation for a clean energy economy September 13, 2010 DOE Announces More than $5 Million to Support Wind Energy Development Funds to Enhance Short-Term Wind Forecasting and Accelerate Midsize Wind

342

Linearization using Digital Predistortion of a High-Speed, Pulsed, Radio Frequency Power Amplifier for VHF Radar Depth-Sounder Systems  

E-Print Network [OSTI]

-lobe levels of 17 dB over the Tukey (transmit) and Blackmann2 (receive) windowing alone. The high-speed switching circuit reduced current consumption to 117 mA (or 3.28 W at +28 V) for a 10-us pulse at 1-kHz PRF....

Player, Kevin

2010-03-29T23:59:59.000Z

343

NREL: Wind Research - Gaia-Wind's 11 Kilowatt Wind Turbine Testing and  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Gaia-Wind's 11 Kilowatt Wind Turbine Testing and Results Gaia-Wind's 11 Kilowatt Wind Turbine Testing and Results A video of Gaia-Wind's 11-kW wind turbine. Text Version As part of the National Renewable Energy Laboratory and U.S. Department of Energy (NREL/DOE) Independent Testing project, NREL tested Gaia-Wind's 11-kilowatt (kW) small wind turbine at the National Wind Technology Center (NWTC). Gaia-Wind's turbine is a three-phase induction generator that operates at 480 volts. The turbine's downwind rotor has a 13-meter diameter, and its tower is 18 meters tall. The two-bladed, oversized rotor is designed for low to moderate wind speeds. Testing Summary The summary of the tests is below with the final reports. Cumulative Energy Production 6/11/2008: 210; 6/13/2008: 528; 6/16/2008: 716; 6/18/2008: 731; 6/19/2008:

344

Blind Test 2 calculations for two in-line model wind turbines where the downstream turbine operates at various rotational speeds  

Science Journals Connector (OSTI)

Abstract In this paper we report on the results of the Blind Test 2 workshop, organized by Norcowe and Nowitech in Trondheim, Norway in October 2012. This workshop was arranged in order to find out how well wind turbine simulation models perform when applied to two turbines operating in line. Modelers with a suitable code were given boundary conditions of a wind tunnel test performed in the large wind tunnel facility at the Department of Energy and Process Engineering, at NTNU Trondheim, where two almost identical model turbines with a diameter of about 0.9?m had been tested under various operating conditions. A detailed geometry specification of the models could be downloaded and the modelers were invited to submit the calculation without knowing the experimental results in advance. Nine different contributions from eight institutions were received, representing a wide range of simulation models, such as a LES coupled with an actuator line rotor model, RANS using an actuator disc, U-RANS models applied to fully resolved turbine model geometries, as well as a vortex panel method. The comparison showed a larger than expected scatter on the performance calculation of the upstream turbine (±20%), and an even higher uncertainty for the downstream turbine, especially at operating conditions close to the runaway point. The modelers were requested to document the wake development downstream of the second turbine, the development behind the first turbine had been the challenge for a previous blind test (see Krogstad and Eriksen [17]). Mean flow calculations reported at X = 1D downstream of the second turbine showed that the models which fully resolved boundary layers on the rotor surface performed best. Including the tower and the hub in the simulation improved the accuracy of the predictions and is essential in capturing the important asymmetries that develop in the wake. These turbine details strongly influence the development near the center of the wake, but are often omitted in simulations in order to incorporate simplifying symmetry conditions in the calculations. Further from the rotor, at X = 4D, the LES simulations coupled to actuator line rotor models performed well and were able to capture the main features of the mean and turbulent flows, while RANS models using actuator disc models showed limitations especially in predicting correctly the turbulent kinetic energy.

Fabio Pierella; Per-Ĺge Krogstad; Lars Sćtran

2014-01-01T23:59:59.000Z

345

Economic feasibility of development of wind power plants in coastal locations of Saudi Arabia – A review  

Science Journals Connector (OSTI)

Climate change and depletion of natural resources are serious issues that have potential impact on the economic and social development of countries. In this perspective, the governments world-wide are mobilizing initiatives to exploit renewable energy sources to mitigate increasing demand of energy, volatile fuel prices, and environmental concerns. Renewable energy (wind/solar) based power system is a nature-friendly option for power production to foster sustainable development challenges. In the present study, the economic feasibility of development of 75 MW wind power plants (wind farms) in the coastal locations of the Kingdom of Saudi Arabia (K.S.A.) has been studied/reviewed by analyzing long-term wind speed data. Attention has been focused on four coastal locations (Al-Wajh, Jeddah, Yanbu and Jizan) covering the west coast. In general, long-term data indicates that the yearly average wind speed of K.S.A. varies from 3.0 to 4.5 m/s at 10 m height. The wind farms simulated consist of different combinations of 600 kW commercial wind machines (50 m hub-height). NREL's (HOMER Energy's) HOMER software has been employed to perform the techno-economic assessment. The study presents monthly variations of wind speed, cumulative frequency distribution (CFD) profiles of wind speed, monthly and yearly amount of energy generated from the 75 MW wind farms (50 m hub-height) at different coastal locations of K.S.A., cost of generating energy (COE, $/kWh), capacity factor (%), etc. The CFD indicates that the wind speeds are less than 3 m/s for 45%, 53%, 41%, and 52% of the time during the year at Al-Wajh, Jeddah, Yanbu and Jizan respectively. This implies that wind electric conversion systems (WECS) will not produce energy for about 41–53% of the time during the year. The annual energy produced by 75 MW wind farms (50 m hub-height) has been found to be 107,196, 81,648, 135,822, and 80,896 MWh at Al-Wajh, Jeddah, Yanbu and Jizan respectively. The cost of wind-based electricity by using 600 kW (50 m hub-height) commercial WECS has been found to be 0.0536, 0.0704, 0.0423, and 0.0711 US$/kWh for Al-Wajh, Jeddah, Yanbu and Jizan respectively. Also, attempt has been made to determine the capacity factor (CF) of wind-based power plants, the CF has been found to vary from 12% to 21% for different locations of the Kingdom.

S.M. Shaahid; L.M. Al-Hadhrami; M.K. Rahman

2013-01-01T23:59:59.000Z

346

Solutions for Interharmonics in Variable Speed Drives for LNG Plants:.  

E-Print Network [OSTI]

??Variable speed drives can cause components of any frequency known as interharmonics. Large variable speed drives in the order of tens of megawatts can replace… (more)

Verhulst, M.P.A.

2011-01-01T23:59:59.000Z

347

Dynamic analysis of a 5 megawatt offshore floating wind turbine  

E-Print Network [OSTI]

wind turbine. Rating Control Rotor Radius Rated Wind Speed Towerwind turbine is used in this design, however there are slight modifications of the tower.of the tower. Figure 2.3: NREL 5 MW Reference Wind Turbine [

Harriger, Evan Michael

2011-01-01T23:59:59.000Z

348

Electric power from offshore wind via synoptic-scale interconnection  

Science Journals Connector (OSTI)

...hub-height of modern offshore wind turbines. Our extrapolation...output of an offshore turbine at each selected station with wind speed measurements...Practical commercial offshore wind developments...minimum of 100 turbines at each location...

Willett Kempton; Felipe M. Pimenta; Dana E. Veron; Brian A. Colle

2010-01-01T23:59:59.000Z

349

Analysis and forecasting of wind velocity in chetumal, quintana roo, using the single exponential smoothing method  

Science Journals Connector (OSTI)

In this paper the analysis and forecasting of wind velocities in Chetumal, Quintana Roo, Mexico is presented. Measurements were made by the Instituto de Investigaciones Eléctricas (IIE) during two years, from 2004 to 2005. This location exemplifies the wind energy generation potential in the Caribbean coast of Mexico that could be employed in the hotel industry in the next decade. The wind speed and wind direction were measured at 10 m above ground level. Sensors with high accuracy and a low starting threshold were used. The wind velocity was recorded using a data acquisition system supplied by a 10 W photovoltaic panel. The wind speed values were measured with a frequency of 1 Hz and the average wind speed was recorded considering regular intervals of 10 min. First a statistical analysis of the time series was made in the first part of the paper through conventional and robust measures. Also the forecasting of the last day of measurements was made utilizing the single exponential smoothing method (SES). The results showed a very good accuracy of the data with this technique for an ? value of 0.9. Finally the SES method was compared with the artificial neural network (ANN) method showing the former better results.

E. Cadenas; O.A. Jaramillo; W. Rivera

2010-01-01T23:59:59.000Z

350

Global ocean wind power sensitivity to surface layer stability  

E-Print Network [OSTI]

observa- tions, vertical wind speed profile estimation givenspeed differences compared to over the Gulf Stream, 80 m wind power is relatively smaller because of reduced verticalvertical momentum transfer over the Gulf Stream and North Atlantic Current results in sub-logarithmic wind profiles, reduced 80 – 10 m wind speed

Capps, Scott B; Zender, Charles S

2009-01-01T23:59:59.000Z

351

Influence of wind characteristics on turbine performance Ioannis Antoniou (1)  

E-Print Network [OSTI]

(2) , Peder Enevoldsen (2) , Leo Thesbjerg (3) (1): Wind Energy Department, Risø of measuring the power curve is by using the wind speed at hub height. The assumption behind this is that the wind speed is representative of the wind over the whole turbine rotor. While this assumption

352

Use of synthetic aperture radar for offshore wind resource assessment and wind farm development in the UK   

E-Print Network [OSTI]

The UK has an abundant offshore wind resource with offshore wind farming set to grow rapidly over the coming years. Optimisation of energy production is of the utmost importance and accurate estimates of wind speed distributions are critical...

Cameron, Iain Dickson

2008-01-01T23:59:59.000Z

353

Wind energy  

Science Journals Connector (OSTI)

Wind energy is rapidly growing. In 2006 the installed generating capacity in the world increased by 25%, a growth rate which has more or less been sustained during the last decade. And there is no reason to believe that this growth will slow significantly in the coming years. For example, the United Kingdom's goal for installed wind turbines by 2020 is 33 GW up from 2 GW in 2006, an average annual growth rate of 22% over that period. More than half of all turbines are installed in Europe, but United States, India and lately China are also rapidly growing markets. The cradle of modern wind energy was set by innovative blacksmiths in rural Denmark. Now the wind provides more than 20% of the electrical power in Denmark, the industry has professionalized and has close ties with public research at universities. This focus issue is concerned with research in wind energy. The main purposes of research in wind energy are to: decrease the cost of power generated by the wind; increase the reliability and predictability of the energy source; investigate and reduce the adverse environmental impact of massive deployment of wind turbines; build research based educations for wind energy engineers. This focus issue contains contributions from several fields of research. Decreased costs cover a very wide range of activities from aerodynamics of the wind turbine blades, optimal site selection for the turbines, optimization of the electrical grid and power market for a fluctuating source, more efficient electrical generators and gears, and new materials and production techniques for turbine manufacturing. The United Kingdom recently started the construction of the London Array, a 1 GW off-shore wind farm east of London consisting of several hundred turbines. To design such a farm optimally it is necessary to understand the chaotic and very turbulent flow downwind from a turbine, which decreases the power production and increases the mechanical loads on other nearby turbines. Also addressed within the issue is how much conventional power production can be replaced by the ceaseless wind, with the question of how Greece's target of 29% renewables by 2020 is to be met efficiently. Other topics include an innovative way to determine the power curve of a turbine experimentally more accurately, the use of fluid dynamics tools to investigate the implications of placing vortex generators on wind turbine blades (thereby possibly improving their efficiency) and a study of the perception of wind turbine noise. It turns out that a small but significant fraction of wind turbine neighbours feel that turbine generated noise impairs their ability to rest. The annoyance is correlated with a negative attitude towards the visual impact on the landscape, but what is cause and effect is too early to say. As mentioned there is a rush for wind turbines in many countries. However, this positive development for the global climate is currently limited by practical barriers. One bottleneck is the difficulties for the sub-suppliers of gears and other parts to meet the demand. Another is the difficulties to meet the demand for engineers specialized in wind. For that reason the Technical University of Denmark (DTU) recently launched the world's first Wind Energy Masters Program. Here and elsewhere in the world of wind education and research we should really speed up now, as our chances of contributing to emission free energy production and a healthier global climate have never been better. Focus on Wind Energy Contents The articles below represent the first accepted contributions and further additions will appear in the near future. Wind turbines—low level noise sources interfering with restoration? Eja Pedersen and Kerstin Persson Waye On the effect of spatial dispersion of wind power plants on the wind energy capacity credit in Greece George Caralis, Yiannis Perivolaris, Konstantinos Rados and Arthouros Zervos Large-eddy simulation of spectral coherence in a wind turbine wake A Jimenez, A Crespo, E Migoya and J Garcia How to improve the estimation of

Jakob Mann; Jens Nřrkćr Sřrensen; Poul-Erik Morthorst

2008-01-01T23:59:59.000Z

354

Optimal Siting of Offshore Wind Farms  

Science Journals Connector (OSTI)

The goal of this study is finding the best location for constructing an offshore wind farm with respect to investment and operation costs and technical limitations. Wind speed, sea depth and distance between shor...

Salman Kheirabadi Shahvali…

2014-01-01T23:59:59.000Z

355

Floating offshore wind farms : demand planning & logistical challenges of electricity generation  

E-Print Network [OSTI]

Floating offshore wind farms are likely to become the next paradigm in electricity generation from wind energy mainly because of the near constant high wind speeds in an offshore environment as opposed to the erratic wind ...

Nnadili, Christopher Dozie, 1978-

2009-01-01T23:59:59.000Z

356

The effects of energy storage properties and forecast accuracy on mitigating variability in wind power generation  

E-Print Network [OSTI]

Electricity generation from wind power is increasing worldwide. Wind power can offset traditional fossil fuel generators which is beneficial to the environment. However, wind generation is unpredictable. Wind speeds have ...

Jaworsky, Christina A

2013-01-01T23:59:59.000Z

357

Prototype bucket foundation for wind turbines  

E-Print Network [OSTI]

Prototype bucket foundation for wind turbines -natural frequency estimation Lars Bo Ibsen Morten bucket foundation for wind turbines -natural frequency estimation by Lars Bo Ibsen Morten Liingaard foundation for wind turbines--natural frequency estimation" is divided into four numbered sections

358

Influence of Thermal Stratification on Wind Profiles for Heights up to 140 m  

E-Print Network [OSTI]

.energiemeteorologie.de The vertical wind speed profile has to be know for many wind power applications. Although the large effect speeds are not measured or predicted in the hubheight of the wind turbine. For the vertical trans stratification of the boundary layer has also an important influence on the vertical wind speed profile. Only

Heinemann, Detlev

359

Measured wind turbine loads and their dependence on inflow parameters L. Manuel & L. D. Nelson  

E-Print Network [OSTI]

of the hub-height horizontal wind speed as well as secondary pa- rameters such as Reynolds stresses, vertical to other previous studies, but we do not bin the data sets by wind speed since dependen- cies in one wind turbine loads. Inflow parameters might include, for example, mean wind speed, turbu- lence intensity

Manuel, Lance

360

Sensitivity of the wind stress and storm surges to surface drag  

E-Print Network [OSTI]

- 29 April 2009 , CD zU ln~ #12;Background Air-Sea Interaction High and/or extreme wind speeds , CD ? #12;Background Air-Sea Interaction High and/or extreme wind speeds ­ Dynamics Sensitivity High and/or extreme wind speeds ­ Dynamics Sensitivity of the wind stress and storm surges to surface

Vries, Hans de

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Wind power forecast error smoothing within a wind farm  

Science Journals Connector (OSTI)

Smoothing of wind power forecast errors is well-known for large areas. Comparable effects within a wind farm are investigated in this paper. A Neural Network was taken to predict the power output of a wind farm in north-western Germany comprising 17 turbines. A comparison was done between an algorithm that fits mean wind and mean power data of the wind farm and a second algorithm that fits wind and power data individually for each turbine. The evaluation of root mean square errors (RMSE) shows that relative small smoothing effects occur. However, it can be shown for this wind farm that individual calculations have the advantage that only a few turbines are needed to give better results than the use of mean data. Furthermore different results occurred if predicted wind speeds are directly fitted to observed wind power or if predicted wind speeds are first fitted to observed wind speeds and then applied to a power curve. The first approach gives slightly better RMSE values, the bias improves considerably.

Nadja Saleck; Lueder von Bremen

2007-01-01T23:59:59.000Z

362

Distributed Wind Energy in Idaho  

SciTech Connect (OSTI)

Project Objective: This project is a research and development program aimed at furthering distributed wind technology. In particular, this project addresses some of the barriers to distributed wind energy utilization in Idaho. Background: At its core, the technological challenge inherent in Wind Energy is the transformation of a highly variable form of energy to one which is compatible with the commercial power grid or another useful application. A major economic barrier to the success of distributed wind technology is the relatively high capital investment (and related long payback periods) associated with wind turbines. This project will carry out fundamental research and technology development to address both the technological and economic barriers. � Active drive train control holds the potential to improve the overall efficiency of a turbine system by allowing variable speed turbine operation while ensuring a tight control of generator shaft speed, thus greatly simplifying power conditioning. � Recent blade aerodynamic advancements have been focused on large, utility-scale wind turbine generators (WTGs) as opposed to smaller WTGs designed for distributed generation. Because of Reynolds Number considerations, blade designs do not scale well. Blades which are aerodynamically optimized for distributed-scale WTGs can potentially reduce the cost of electricity by increasing shaft-torque in a given wind speed. � Grid-connected electric generators typically operate at a fixed speed. If a generator were able to economically operate at multiple speeds, it could potentially convert more of the wind�s energy to electricity, thus reducing the cost of electricity. This research directly supports the stated goal of the Wind and Hydropower Technologies Program for Distributed Wind Energy Technology: By 2007, reduce the cost of electricity from distributed wind systems to 10 to 15 cents/kWh in Class 3 wind resources, the same level that is currently achievable in Class 5 winds.

Gardner, John; Ferguson, James; Ahmed-Zaid, Said; Johnson, Kathryn; Haynes, Todd; Bennett, Keith

2009-01-31T23:59:59.000Z

363

Operating wind turbines in strong wind conditions by using feedforward-feedback control  

Science Journals Connector (OSTI)

Due to the increasing penetration of wind energy into power systems, it becomes critical to reduce the impact of wind energy on the stability and reliability of the overall power system. In precedent works, Shen and his co-workers developed a re-designed operation schema to run wind turbines in strong wind conditions based on optimization method and standard PI feedback control, which can prevent the typical shutdowns of wind turbines when reaching the cut-out wind speed. In this paper, a new control strategy combing the standard PI feedback control with feedforward controls using the optimization results is investigated for the operation of variable-speed pitch-regulated wind turbines in strong wind conditions. It is shown that the developed control strategy is capable of smoothening the power output of wind turbine and avoiding its sudden showdown at high wind speeds without worsening the loads on rotor and blades.

Ju Feng; Wen Zhong Sheng

2014-01-01T23:59:59.000Z

364

Wind?energy farm noise impacts on nearby residences—the citizen's view  

Science Journals Connector (OSTI)

Wind?energy farms with hundreds of wind turbines have proliferated in close proximity to residential properties without any apparent control on the noise impact consequences. Annoying and intrusive wind turbinenoise occurred as soon as the first turbines were installed. The adverse noise impact has continued and intensified as additional WECS (wind energy conversion system) sites were approved and developed with the installation of hundreds of additional turbines. The adverse noiseeffects consist of low?frequency noise that is not fully addressed or controlled by only A?weighted sound level standards pure tones and higher noise levels during higher wind?speed conditions. More stringent noise controls should have been implemented in the beginning. Riverside County has recently adopted a more stringent noise standard that also includes a pure tone restriction that will apply to future sites. However mitigation of the mistakes made at the earlier sites remains to be resolved.

John R. Warner

1986-01-01T23:59:59.000Z

365

Measured speed versus true speed  

E-Print Network [OSTI]

The theoretical predictions, derived from the Lorentz and the Tangherlini transformations, for the one-way speed of any physical entity are confronted with the corresponding expressions for the one-way measured speed obtained from a gedanken experiment. The experiment demonstrates that, for an inertial frame $K'$ in motion relative to an inertial frame $K$ where the one-way speed of light is isotropic, even the special theory of relativity renders the one-way speed of light as function of the velocity of $K'$ in agreement with the Tangherlini transformations. However, the two-way speed of light remains constant for all inertial frames, in agreement with the two-way experimental techniques. This implies that there must exist \\emph{one and only one} inertial frame where the one-way speed of light is isotropic. These investigations also show how we can determine, with certain restrictions, the true speed of a physical entity and of the true speed of $K'$ relative to $K$.

Israel Perez

2010-05-10T23:59:59.000Z

366

Uncovering wind turbine properties through two-dimensional stochastic modeling of wind dynamics  

E-Print Network [OSTI]

Using a method for stochastic data analysis, borrowed from statistical physics, we analyze synthetic data from a Markov chain model that reproduces measurements of wind speed and power production in a wind park in Portugal. From the theoretical point of view we argue that our methods can be used to extract unknown functional relations between two variables. We first show that indeed our analysis retrieves the power performance curve, which yields the relationship between wind speed and power production and discuss how such procedure can be extended for extracting functional relationships between pairs of physical variables in general. Second, we show how specific features, such as the turbine rated wind speed or the descriptive wind speed statistics, can be related with the equations describing the evolution of power production and wind speed at single wind turbines.

Raischel, Frank; Lopes, Vitor V; Lind, Pedro G

2012-01-01T23:59:59.000Z

367

Environmental impact of wind energy  

Science Journals Connector (OSTI)

One purpose of wind turbines is to provide pollution-free electric power at a reasonable price in an environmentally sound way. In this focus issue the latest research on the environmental impact of wind farms is presented. Offshore wind farms affect the marine fauna in both positive and negative ways. For example, some farms are safe havens for porpoises while other farms show fewer harbor porpoises even after ten years. Atmospheric computer experiments are carried out to investigate the possible impact and resource of future massive installations of wind turbines. The following questions are treated. What is the global capacity for energy production by the wind? Will the added turbulence and reduced wind speeds generated by massive wind farms cool or heat the surface? Can wind farms affect precipitation? It is also shown through life-cycle analysis how wind energy can reduce the atmospheric emission of eight air pollutants. Finally, noise generation and its impact on humans are studied.

J Mann; J Teilmann

2013-01-01T23:59:59.000Z

368

Evaluation of global wind power Cristina L. Archer and Mark Z. Jacobson  

E-Print Network [OSTI]

Evaluation of global wind power Cristina L. Archer and Mark Z. Jacobson Department of Civil the world's wind power potential for the first time from data. Wind speeds are calculated at 80 m, the hub% of all reporting stations experience annual mean wind speeds ! 6.9 m/s at 80 m (i.e., wind power class 3

369

Is the Weibull distribution really suited for wind statistics modeling and wind power evaluation?  

E-Print Network [OSTI]

Wind speed statistics is generally modeled using the Weibull distribution. This distribution is convenient since it fully characterizes analytically with only two parameters (the shape and scale parameters) the shape of distribution and the different moments of the wind speed (mean, standard deviation, skewness and kurtosis). This distribution is broadly used in the wind energy sector to produce maps of wind energy potential. However, the Weibull distribution is based on empirical rather than physical justification and might display strong limitations for its applications. The philosophy of this article is based on the modeling of the wind components instead of the wind speed itself. This provides more physical insights on the validity domain of the Weibull distribution as a possible relevant model for wind statistics and the quantification of the error made by using such a distribution. We thereby propose alternative expressions of more suited wind speed distribution.

Drobinski, Philippe

2012-01-01T23:59:59.000Z

370

PSO (FU 2101) Ensemble-forecasts for wind power  

E-Print Network [OSTI]

PSO (FU 2101) Ensemble-forecasts for wind power Wind Power Ensemble Forecasting Using Wind Speed the problems of (i) transforming the meteorological ensembles to wind power ensembles and, (ii) correcting) data. However, quite often the actual wind power production is outside the range of ensemble forecast

371

Wind Farm Power Prediction: A Data-Mining Approach  

E-Print Network [OSTI]

into a wind power plant. A number of different approaches have been used in forecasting wind speed and windWind Farm Power Prediction: A Data-Mining Approach Andrew Kusiak*, Haiyang Zheng and Zhe Song, IA 52242­1527, USA In this paper, models for short- and long-term prediction of wind farm power

Kusiak, Andrew

372

Ris-R-1111(EN) Ultimate Loading of Wind Turbines  

E-Print Network [OSTI]

-R-1111(EN) 2 Abstract An extreme loading study has been conducted comprising a general wind climate the environmental wind climate. With the trend of persistently growing turbines, the extreme loading seems to become, and extreme wind events. Examples of extreme wind events are extreme mean wind speeds with a recurrence period

373

Analysis of wind turbine vibrations based on SCADA data  

E-Print Network [OSTI]

Vibrations of a wind turbine have a negative impact on its performance. Mitigating this undesirable impact requires knowledge of the relationship between the vibrations and other wind turbine parameters that could be potentially modified. Three approaches for ranking the impact importance of measurable turbine parameters on the vibrations of the drive train and the tower are discussed. They include the predictor importance analysis, the global sensitivity analysis, and the correlation coefficient analysis versed in data mining and statistics. To decouple the impact of wind speed on the vibrations of the drive train and the tower, the analysis is performed on data sets with narrow speed ranges. Wavelet analysis is applied to filter noisy accelerometer data. To exclude the impact malfunctions on the vibration analysis, the data are analyzed in a frequency domain. Data-mining algorithms are used to build models with turbine parameters of interest as inputs, and the vibrations of drive train and tower as outputs. The performance of each model is thoroughly evaluated based on metrics widely used in the wind industry. The neural network algorithm outperforms other classifiers and is considered to be the most promising approach to study wind turbine vibrations. ?DOI: 10.1115/1.4001461?

Andrew Kusiak; Zijun Zhang

2010-01-01T23:59:59.000Z

374

Optimum propeller wind turbines  

SciTech Connect (OSTI)

The Prandtl-Betz-Theodorsen theory of heavily loaded airscrews has been adapted to the design of propeller windmills which are to be optimized for maximum power coefficient. It is shown that the simpler, light-loading, constant-area wake assumption can generate significantly different ''optimum'' performance and geometry, and that it is therefore not appropriate to the design of propeller wind turbines when operating in their normal range of high-tip-speed-to-wind-speed ratio. Design curves for optimum power coefficient are presented and an example of the design of a typical two-blade optimum rotor is given.

Sanderson, R.J.; Archer, R.D.

1983-11-01T23:59:59.000Z

375

Dynamic stall analysis of horizontal-axis-wind-turbine blades using computational fluid dynamics  

Science Journals Connector (OSTI)

Dynamic stall has been widely known to significantly affect the performance of the wind turbines. In this paper aerodynamic simulation of the unsteady low-speed flow past two-dimensional wind turbine blade profiles developed by the National Renewable Energy Laboratory (NREL) will be performed. The aerodynamic simulation will be performed using Computational Fluid Dynamics (CFD). The governing equations used in the simulations are the Unsteady-Reynolds-Averaged-Navier-Stokes (URANS) equations. The unsteady separated turbulent flow around an oscillating airfoil pitching in a sinusoidal pattern in the regime of low Reynolds number is investigated numerically. The investigation employs the URANS approach with the most suitable turbulence model. The development of the light dynamic stall of the blades under consideration is studied. The S809 blade profile is simulated at different mean wind speeds. Moreover the S826 blade profile is also considered for analysis of wind turbine blade which is the most suitable blade profile for the wind conditions in Egypt over the site of Gulf of El-Zayt. In order to find the best oscillating frequency different oscillating frequencies are studied. The best frequency can then be used for the blade pitch controller. The comparisons with the experimental results showed that the used CFD code can accurately predict the blade profile unsteady aerodynamic loads.

2012-01-01T23:59:59.000Z

376

E-Print Network 3.0 - aggregated wind power Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and the increased wind power penetration in power systems the main trend for modern wind turbines is clearly... variable speed operation and grid connection via ... Source: Ris...

377

NREL GIS Data: Global Offshore Wind - Datasets - OpenEI Datasets  

Open Energy Info (EERE)

NREL GIS Data: Global ... Dataset Activity Stream NREL GIS Data: Global Offshore Wind GIS data for offshore wind speed (meterssecond). Specified to Exclusive Economic Zones (EEZ)....

378

Quantifying the system balancing cost when wind energy is incorporated into electricity generation system.  

E-Print Network [OSTI]

??Incorporation of wind energy into the electricity generation system requires a detailed analysis of wind speed in order to minimize system balancing cost and avoid… (more)

Issaeva, Natalia

2009-01-01T23:59:59.000Z

379

Microphysical Structure of the Marine Boundary Layer under Strong Wind and Spray Formation as Seen from Simulations Using a 2D Explicit  

E-Print Network [OSTI]

in the vertical profiles of wind speed occurring with in- creasing wind speeds were attributed to a decrease generation is de- termined by a source function depending on the background wind speed assumed in the surface roughness and the drag coefficient for wind speeds exceeding about 33 m s21 . This decrease

Mark, Pinsky

380

Active control system for high speed windmills  

DOE Patents [OSTI]

A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed. 4 figs.

Avery, D.E.

1988-01-12T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Wind derivatives: hedging wind risk:.  

E-Print Network [OSTI]

??Wind derivatives are financial contracts that can be used to hedge or mitigate wind risk. In this thesis, the focus was on pricing these wind… (more)

Hoyer, S.A.

2013-01-01T23:59:59.000Z

382

Characteristics of 50–200-m Winds and Temperatures Derived from an Iowa Tall-Tower Network  

Science Journals Connector (OSTI)

Limitations in skill of wind speed forecasts lead to conservative bids of wind-plant production in the day-ahead energy market and usually to an underutilization of wind resources. Improvements are needed in understanding wind characteristics in ...

Renee A. Walton; Eugene S. Takle; William A. Gallus Jr.

2014-10-01T23:59:59.000Z

383

Eastern Frequency Response Study  

SciTech Connect (OSTI)

This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

Miller, N.W.; Shao, M.; Pajic, S.; D'Aquila, R.

2013-05-01T23:59:59.000Z

384

Magnetically Coupled Adjustable Speed Motor Drives  

Broader source: Energy.gov [DOE]

Alternating current electric motors rotate at a nearly constant speed that is determined by motor design and line frequency. Energy savings of 50% or more may be available when fixed speed systems are modified to allow the motor speed to match variable load requirements of a centrifugal fan or pump. This tip sheet describes the advantages of magnetically coupled ASDs and provides suggested actions.

385

Can Wind Lidars Measure Turbulence?  

Science Journals Connector (OSTI)

Modeling of the systematic errors in the second-order moments of wind speeds measured by continuous-wave (ZephIR) and pulsed (WindCube) lidars is presented. These lidars use the conical scanning technique to measure the velocity field. The model ...

A. Sathe; J. Mann; J. Gottschall; M. S. Courtney

2011-07-01T23:59:59.000Z

386

Massachusetts Wind Turbine Acoustics Research Project—Goals and preliminary results  

Science Journals Connector (OSTI)

The Commonwealth of Massachusetts (USA) has 43 operating wind turbine projects of 100 kW or more. At several of these projects noise complaints have been made to state authorities. The Massachusetts Clean Energy Center which provides funding for early stage analysis and development of wind power projects and the Massachusetts Department of Environmental Protection which regulates noise launched the project to increase understanding of (1) wind turbine acoustic impacts taking into account variables such as wind turbine size technology wind speed topography and distance and (2) the generation propagation and measurement of sound around wind turbine projects to inform policy-makers on how pre- and post-construction wind turbine noise studies should be conducted. This study involved the collection of detailed sound and meteorological data at five locations. The resulting database and interim reports contain information on infrasound and audible frequencies including amplitude modulation tonality and level. Analyses will include how the effects of wind shear and other variables may affect these parameters. Preliminary findings reflect the effects of meteorological conditions on wind turbine sound generation and propagation.

2014-01-01T23:59:59.000Z

387

Wind velocity measurements using a pulsed LIDAR system: first results  

E-Print Network [OSTI]

. A laser beam of 1.54 µm wavelength takes measurements of the wind speed in beamwise direction. To obtain the three-dimensinal wind vector, the beam is inclined by 30 from vertical direction and measurements 12345 t [s] vh[m/s] Figure 2. Segment of measured time series of the horizontal wind speed magnitude vh

Peinke, Joachim

388

Improving an Accuracy of ANN-Based Mesoscale-Microscale Coupling Model by Data Categorization: With Application to Wind Forecast for Offshore and Complex Terrain Onshore Wind Farms  

Science Journals Connector (OSTI)

The ANN-based mesoscale-microscale coupling model forecasts wind speed and wind direction with high accuracy for wind parks located in complex terrain onshore, yet some weather regimes remains unresolved and f...

Alla Sapronova; Catherine Meissner…

2014-01-01T23:59:59.000Z

389

Distribution of Extreme Winds in the Bonneville Power Administration Service Area  

Science Journals Connector (OSTI)

Annual extreme 1 min wind speeds at 78 Pacific Northwest locations were analyzed using the Fisher-Tippet type II extreme value function. From computed mean recurrence intervals, we could easily determine the wind speed likely to recur in a ...

J. William Wantz; Robert E. Sinclair

1981-12-01T23:59:59.000Z

390

Market penetration of wind turbine concepts over the years Anca D. Hansen1  

E-Print Network [OSTI]

speed wind turbine concept with partial-scale power converter (DFIG) This configuration denotes the variable speed controlled wind turbine with doubly fed induction generator (DFIG) and pitch control

391

Variable susceptance excitation control for dynamic performance improvement of a stand-alone wind turbine induction generator system  

Science Journals Connector (OSTI)

Isolated wind farms employ simple squirrel cage induction generators driven by variable speed wind turbines. Lacking control capability, such generation can contribute very little to network support. Wind turbines mostly do not take part in voltage and frequency control and if a disturbance occurs, the turbines may be disconnected and reconnected when normal operation has been resumed. From operation viewpoint, this is definitely not acceptable. A primary reason for the rigidity of operation is the lack of excitation adaptation under variable wind conditions. This article proposes incorporation of a variable capacitance controller at the generator terminal which will automatically adjust the needed excitation. Further improvement of transient profile of the stand-alone wind turbine generator has been proposed through inclusion of additional stabilising control. Simulation studies show that the proposed excitation controller with additional PID circuit provides very good transient profile following reasonable input torque variations.

A.H.M.A. Rahim; M. Ahsanul Alam

2009-01-01T23:59:59.000Z

392

Wind Structure in the Atmospheric Boundary Layer  

Science Journals Connector (OSTI)

13 May 1971 research-article Wind Structure in the Atmospheric Boundary Layer...semi-empirical laws for the variation of mean wind speed with height and for the statistical...provide some useful ordering of the mean wind profile characteristics in relation to...

1971-01-01T23:59:59.000Z

393

Offshore wind resource assessment through satellite images  

E-Print Network [OSTI]

1 Slide no. 4 Offshore wind resource assessment through satellite images Charlotte Bay Hasager images for offshore wind ressource assessment in lieu of in-situ mast observations #12;4 Slide no Hasager, Dellwik, Nielsen and Furevik, 2004, Validation of ERS-2 SAR offshore wind-speed maps in the North

394

Offshore Wind Turbine Wakes Measured by Sodar  

Science Journals Connector (OSTI)

A ship-mounted sodar was used to measure wind turbine wakes in an offshore wind farm in Denmark. The wake magnitude and vertical extent were determined by measuring the wind speed profile behind an operating turbine, then shutting down the ...

R. J. Barthelmie; L. Folkerts; F. T. Ormel; P. Sanderhoff; P. J. Eecen; O. Stobbe; N. M. Nielsen

2003-04-01T23:59:59.000Z

395

Wind Speed Scaling in Fully Developed Seas  

Science Journals Connector (OSTI)

Recent tests of all generations of numerical wave models indicate that extreme wave heights are significantly underpredicted by these models. This behavior is consistent with the finding by Ewing and Laing that fully developed wave spectra do not ...

Donald T. Resio; Val R. Swail; Robert E. Jensen; Vincent J. Cardone

1999-08-01T23:59:59.000Z

396

Final Statewide Wind Maps and Modifications Report N e v a d aN e v a d a  

E-Print Network [OSTI]

4500000 4500000 4750000 4750000 Mean Annual Wind Speed of California at 30 MetersMean Annual Wind Speed 4500000 4500000 4750000 4750000 Mean Annual Wind Speed of California at 50 MetersMean Annual Wind SpeedV Final Statewide Wind Maps and Modifications Report #12;N e v a d aN e v a d a O r e g o nO r e g

397

Abstract--Wind power generation is growing rapidly. However, maintaining the wind turbine connection to grid is a real  

E-Print Network [OSTI]

1 Abstract--Wind power generation is growing rapidly. However, maintaining the wind turbine and the generator design. The fixed-speed wind turbine has the advantage of the low cost of A. F. Abdou and H. R advantages over the fixed-speed operation, such as maximum power capture, less mechanical stresses, and less

Pota, Himanshu Roy

398

Wind power generating system  

SciTech Connect (OSTI)

Normally feathered propeller blades of a wind power generating system unfeather in response to the actuation of a power cylinder that responds to actuating signals. Once operational, the propellers generate power over a large range of wind velocities. A maximum power generation design point signals a feather response of the propellers so that once the design point is reached no increase in power results, but the system still generates power. At wind speeds below this maximum point, propeller speed and power output optimize to preset values. The propellers drive a positive displacement pump that in turn drives a positive displacement motor of the swash plate type. The displacement of the motor varies depending on the load on the system, with increasing displacement resulting in increasing propeller speeds, and the converse. In the event of dangerous but not clandestine problems developing in the system, a control circuit dumps hydraulic pressure from the unfeathering cylinder resulting in a predetermined, lower operating pressure produced by the pump. In the event that a problem of potentially cladestine consequence arises, the propeller unfeathering cylinder immediately unloads. Upon startup, a bypass around the motor is blocked, applying a pressure across the motor. The motor drives the generator until the generator reaches a predetermined speed whereupon the generator is placed in circuit with a utility grid and permitted to motor up to synchronous speed.

Schachle, Ch.; Schachle, E. C.; Schachle, J. R.; Schachle, P. J.

1985-03-12T23:59:59.000Z

399

Using a DFIG-based wind farm for grid node reactive power compensation  

Science Journals Connector (OSTI)

Grid nodes voltages are not allowed to deviate excessively from nominal value. Appropriate measures should be taken to prevent such a deviation. The voltage difference between two nodes is strongly affected by reactive power flow. In contrast to frequency control, node voltage control must be achieved locally. This article investigates the use of a wind farm based on a doubly fed induction generators (DFIG) for reactive power compensation of a grid node. A wind speed variation sample is applied to the model of a wind power unit. The power flow between the stator of the DFIG-based wind power unit and the grid is controlled by using the decoupled active and reactive power vector control method. The limits or capacity of the stator and power converters to consume or provide reactive power are discussed. SIMULINK software has been used for the simulation of the system.

Mohamed Kesraoui; Ahmed Chaib; Abdullah Madri; Bilal Hammani

2013-01-01T23:59:59.000Z

400

Stakeholder Engagement and Outreach: Where Is Wind Power?  

Wind Powering America (EERE)

Where Is Wind Power? Where Is Wind Power? Wind Powering America offers maps to help you visualize the wind resource at a local level and to show how much wind power has been installed in the United States. How much wind power is on my land? Go to the wind resource maps. Go to the wind resource maps. Go to the wind resource maps. If you want to know how much wind power is in a particular area, these wind resource maps can give you a visual indication of the average wind speeds to a local level such as a neighborhood. These maps have been developed using the same mathematical models that are used by weather forecasters and are even used to estimate the wind energy potential-or how much wind energy could potentially be produced at the state level, if wind power were developed there.

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Reactive capability limits of wind farms  

Science Journals Connector (OSTI)

Wind Energy Conversion Systems (WECS) technology can be classified into two main types: fixed speed and variable speed. Fixed speed WECS use an induction generator connected directly to the grid while variable speed WECS use a power converter to connect the generator to the grid. Fixed speed WECS require shunt capacitors for reactive power compensation, while variable speed WECS have reactive power capability. Under the Spanish grid code, wind farms have to operate in a range of power factor values. This paper determines the reactive power capability of wind farms equipped with both fixed and variable speed WECS. The reactive power capability can be represented as a reactive capability curve. In this paper, the reactive capability curve is used to calculate the additional reactive power compensation needed to meet the requirements of the Spanish grid code.

Alberto Rios Villacorta; Santiago Arnaltes Gomez; Jose Luis Rodriguez-Amenedo

2005-01-01T23:59:59.000Z

402

RELIABILITY OF WIND POWER FROM DISPERSED SITES: A PRELIMINARY ASSESSMENT  

E-Print Network [OSTI]

ON METHODOLOGY: FROM WIND POWER FREQUENCY TO LOSS-OF-LOADJ.P. , "Some Aspects of Wind Power Statistics, " J. of Appl.SŁCTION Reliability of Wind Power From Dispersed Sites: A Pr

Kahn, E.

2011-01-01T23:59:59.000Z

403

New England Wind Forum: Determining Factors Influencing Wind Economics in  

Wind Powering America (EERE)

Determining Factors Influencing Wind Economics in New England Determining Factors Influencing Wind Economics in New England Figure 1: Installed Wind Project Costs by Region: 2003 through 2006 Projects Only New England's high land values, smaller land parcels, varied terrain, and more moderate wind speeds make for projects of smaller scale and higher unit cost than those likely to be built in Texas or the Great Plains states. Click on the graph to view a larger version. New England's high land values, smaller land parcels, varied terrain, and more moderate wind speeds make for projects of smaller scale and higher unit cost than those likely to be built in Texas or the Great Plains states. View a larger version of the graph. Figure 2: 2006 Project Capacity Factors by Region: 2002 through 2005 Projects Only The chart depicts project capacity factor by region. Click on the graph to view a larger version.

404

Chapter Seven - Variable speed drives  

Science Journals Connector (OSTI)

Publisher Summary The electromechanical controllers are a kind of variable speed drives (VSDs) that are obsolete but are still in use because when a motor and a drive is combined, they become a power drive system (PDS). There are two ways of varying the speed of an induction motor, either by varying the motor slip or by varying the supply frequency. The preferred practice for electrical speed variation is to change the supply frequency with a variable frequency drive (VFD). Many other designs also have been developed. However, except the specialized applications, few are still in operation. A number of motor and drive manufacturers are now producing the integrated motor/VFD units. These units consist of a motor and a specially designed VFD, produced as a single package, with the VFD unit mounted variously on the top, side, or end of the motor.

Europump; Hydraulic Institute

2005-01-01T23:59:59.000Z

405

Confronting the winds: orientation and flight behaviour of roosting swifts, Apus apus  

Science Journals Connector (OSTI)

...expected to match the wind speed up to the maximum speed that their power capacity allows...stationary ight into the wind at speed W, under...conditions of a convex power func- tion P(V...carried away by the wind. 3. METHODS We used...X-band, 200kW peak power, 0.25ms pulse duration...

2001-01-01T23:59:59.000Z

406

Final Technical Report Recovery Act: Online Nonintrusive Condition Monitoring and Fault Detection for Wind Turbines  

SciTech Connect (OSTI)

The penetration of wind power has increased greatly over the last decade in the United States and across the world. The U.S. wind power industry installed 1,118 MW of new capacity in the first quarter of 2011 alone and entered the second quarter with another 5,600 MW under construction. By 2030, wind energy is expected to provide 20% of the U.S. electricity needs. As the number of wind turbines continues to grow, the need for effective condition monitoring and fault detection (CMFD) systems becomes increasingly important [3]. Online CMFD is an effective means of not only improving the reliability, capacity factor, and lifetime, but it also reduces the downtime, energy loss, and operation and maintenance (O&M) of wind turbines. The goal of this project is to develop novel online nonintrusive CMFD technologies for wind turbines. The proposed technologies use only the current measurements that have been used by the control and protection system of a wind turbine generator (WTG); no additional sensors or data acquisition devices are needed. Current signals are reliable and easily accessible from the ground without intruding on the wind turbine generators (WTGs) that are situated on high towers and installed in remote areas. Therefore, current-based CMFD techniques have great economic benefits and the potential to be adopted by the wind energy industry. Specifically, the following objectives and results have been achieved in this project: (1) Analyzed the effects of faults in a WTG on the generator currents of the WTG operating at variable rotating speed conditions from the perspective of amplitude and frequency modulations of the current measurements; (2) Developed effective amplitude and frequency demodulation methods for appropriate signal conditioning of the current measurements to improve the accuracy and reliability of wind turbine CMFD; (3) Developed a 1P-invariant power spectrum density (PSD) method for effective signature extraction of wind turbine faults with characteristic frequencies in the current or current demodulated signals, where 1P stands for the shaft rotating frequency of a WTG; (4) Developed a wavelet filter for effective signature extraction of wind turbine faults without characteristic frequencies in the current or current demodulated signals; (5) Developed an effective adaptive noise cancellation method as an alternative to the wavelet filter method for signature extraction of wind turbine faults without characteristic frequencies in the current or current demodulated signals; (6) Developed a statistical analysis-based impulse detection method for effective fault signature extraction and evaluation of WTGs based on the 1P-invariant PSD of the current or current demodulated signals; (7) Validated the proposed current-based wind turbine CMFD technologies through extensive computer simulations and experiments for small direct-drive WTGs without gearboxes; and (8) Showed, through extensive experiments for small direct-drive WTGs, that the performance of the proposed current-based wind turbine CMFD technologies is comparable to traditional vibration-based methods. The proposed technologies have been successfully applied for detection of major failures in blades, shafts, bearings, and generators of small direct-drive WTGs. The proposed technologies can be easily integrated into existing wind turbine control, protection, and monitoring systems and can be implemented remotely from the wind turbines being monitored. The proposed technologies provide an alternative to vibration-sensor-based CMFD. This will reduce the cost and hardware complexity of wind turbine CMFD systems. The proposed technologies can also be combined with vibration-sensor-based methods to improve the accuracy and reliability of wind turbine CMFD systems. When there are problems with sensors, the proposed technologies will ensure proper CMFD for the wind turbines, including their sensing systems. In conclusion, the proposed technologies offer an effective means to achieve condition-based smart maintenance for wind turbines and have a gre

Wei Qiao

2012-05-29T23:59:59.000Z

407

Real time grid congestion management in presence of high penetration of wind energy  

E-Print Network [OSTI]

Real time grid congestion management in presence of high penetration of wind energy A. Vergnol1 , J », « Wind energy », « Variable speed drive » Abstract With the increased use of wind energy the power

Boyer, Edmond

408

Steady and Unsteady Wind Loading of Buildings and Structures [and Discussion  

Science Journals Connector (OSTI)

...terrain are briefly discussed. For design based on steady wind loadings the design wind speed is dependent on the acceptable degree of risk. Force and pressure coefficients may be influenced by Reynolds number, surface roughness, wind characteristics...

1971-01-01T23:59:59.000Z

409

Sensitivity analysis of offshore wind turbine tower caused by the external force  

Science Journals Connector (OSTI)

Generally, faster wind speeds are observed in coastal areas than ... inland areas. Therefore, for the development of offshore wind energy, more electricity is expected to be generated using wind turbines. This al...

Namhyeong Kim; Jung Woon Jin

2013-07-01T23:59:59.000Z

410

INTEGRATION OF RENEWABLE ENERGY SYSTEMS TO ISOLATED DESERT SITE IN EGYPT. Part I: Wind System Optimisation  

Science Journals Connector (OSTI)

ABSTRACT This paper discusses the technical and economical studies and the conceptual system designs for using renewable energy sources such as photovoltaic (PV), wind and biogas supplemented by conventional energy sources as an integerated system to isolated desert site south west of Egypt. (East Oweinat). The first part deals with the wind system optimisation . An attempt has been done, to find an analytical expression and graphical presentation for the proper tower height of a given Wind Energy Conversion System (WECS). This height is expressed as a function of both WECS characteristic speeds (Vci & Vr), and parameters of the site wind speed frequency distribution(WSFD). Application of the derived formula at different sites, and upon various WECS's shows that installing the WECS at that height ensures a high capacity factor of not less than 0.4 for the WECS. The paper also presents the possibility of determining that height directly from the given nomogram. KEY WORDS Wind system optimisation; integrated renewable energy system; wind energy conversion system; desert development; optimum height.

M. Galal Osman; M. Galal Osman; Fathy M.H. Youssef; Sobhy M. Abdelkader; Fathy M.H. Youssef; Sobhy M. Abdelkader

1988-01-01T23:59:59.000Z

411

Wind Resource Assessment Using SODAR at Cluttered Sites William LW Henson MSc*  

E-Print Network [OSTI]

. The UMass ART VT-1 SODAR measures wind speed and direction at multiple heights using the Doppler shift tilted (approximately 15 degrees) from vertical. Three sound beams are required to resolve the wind periods of approximately ten minutes to produce estimates of the mean wind- speed and wind

Massachusetts at Amherst, University of

412

What are the frequencies of standing magnetopause surface waves?  

E-Print Network [OSTI]

We estimate, for the first time, the distribution of standing magnetopause surface wave (also called Kruskal-Schwartzschild mode) frequencies using realistic models of the magnetosphere and magnetosheath utilising an entire solar cycle's worth of solar wind data. Under non-storm times or northward interplanetary magnetic field (IMF), the most likely fundamental frequency is calculated to be 0.64$\\pm$0.06 mHz, consistent with that previously inferred from observed oscillation periods of the boundary. However, the distributions exhibit significant spread (of order $\\pm$0.3 mHz), much larger than suggested by proponents of discrete, stable "magic" frequencies of magnetospheric oscillation. The frequency is found to be most dependent on the solar wind speed, southward component of the IMF and the Dst index, with the latter two being due to the erosion of the magnetosphere by reconnection and the former an effect of the expression for the surface wave phase speed. Finally, the occurrence of Kruskal-Schwartzschild ...

Archer, Martin

2014-01-01T23:59:59.000Z

413

Statistical Features of the Wind Field over the Indian Ccean for the period 1998-2008  

E-Print Network [OSTI]

We have done a statistical analysis of the wind field from the archive of NCEP/NOAA over the Indian Ocean for the period 1998-2008yy, which is given on a grid 1x1.25 of latitude-longitude with 3h time-step. Initial analysis includes mapping the average wind fields and fields of mean density of the wind-kinetic-energy flux , obtained with different periods of time averaging T, as well as the assessment of 11-year trends in these fields. The subsequent analysis is concerned with partition of the Indian ocean area into 6 zones, provided by the spatial inhomogeneity of the analyzed wind field. This analysis includes: a) an assessment of temporal variations for the wind speed field averaged over the Ocean and the zones and for the field of wind-energy flux; b) construction of time history series of these fields averaged with different scales, and estimating frequency spectra of these series; c) finding the extremes of the wind field (in the zones of Indian Ocean); d) construction of histograms of the wind field; ...

Polnikov, Vladislav; Sannasiraj, S A

2011-01-01T23:59:59.000Z

414

ARM - Measurement - Horizontal wind  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

govMeasurementsHorizontal wind govMeasurementsHorizontal wind ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Horizontal wind The horizontal wind in terms of either speed and direction, or the zonal (u) and meridional (v) components. Categories Atmospheric State Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments SONDE : Balloon-Borne Sounding System CO2FLX : Carbon Dioxide Flux Measurement Systems ECOR : Eddy Correlation Flux Measurement System DISDROMETER : Impact Disdrometer

415

Semiconductor Laser Lidar Wind Velocity Sensor for Turbine Control  

Science Journals Connector (OSTI)

A dual line-of-sight CW lidar that measures both wind speed and direction is presented. The wind lidar employs a semiconductor laser, which allows for inexpensive remote sensors geared...

Rodrigo, Peter John; Hu, Qi; Pedersen, Christian

416

Simulation and Optimization of Wind Farm Operations under Stochastic Conditions  

E-Print Network [OSTI]

generation model, wind speed model, and maintenance model. We provide practical insights gained by examining di erent maintenance strategies. To the best of our knowledge, our simulation model is the rst discrete-event simulation model for wind farm...

Byon, Eunshin

2011-08-08T23:59:59.000Z

417

A simulation-based planning system for wind turbine construction  

Science Journals Connector (OSTI)

Wind turbine construction is a challenging undertaking due to the need to lift heavy loads to high locations in conditions of high and variable wind speeds. These conditions create great risks to contractors during the turbine assembly process. This ...

Dina Atef; Hesham Osman; Moheeb Ibrahim; Khaled Nassar

2010-12-01T23:59:59.000Z

418

Pitfalls of modeling wind power using Markov chains  

E-Print Network [OSTI]

An increased penetration of wind turbines have given rise to a need for wind speed/power models that generate realistic synthetic data. Such data, for example, might be used in simulations to size energy storage or spinning ...

Kirtley, James L., Jr.

419

Calculation Method of Losses and Efficiency of Wind Generators  

Science Journals Connector (OSTI)

In the methods presented in this chapter, wind speed is used as the input data, ... conditions of the WG system, for example, wind turbine output, generator output, output power to the power grid, and various los...

Junji Tamura

2012-01-01T23:59:59.000Z

420

Dynamic Simulation of DFIG Wind Turbines on FPGA Boards  

E-Print Network [OSTI]

Dynamic Simulation of DFIG Wind Turbines on FPGA Boards Hao Chen, Student Member, IEEE, Song Sun is a friction coefficient. The wind turbine model is based on the relation between the upstream wind speed V w + 1 where p is the air density; Rw is the wind turbine radius; cp (A, (3) is the performance

Zambreno, Joseph A.

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Ris National Laboratory Satellite SAR applied in offshore wind  

E-Print Network [OSTI]

Risø National Laboratory Satellite SAR applied in offshore wind ressource mapping: possibilities is to quantify the regional offshore wind climate for wind energy application based on satellite SAR ·Study of 85SAR(m/s) Hasager, Dellwik, Nielsen and Furevik, 2004, Validation of ERS-2 SAR offshore wind-speed maps

422

WIND ENERGY Wind Energ. (2014)  

E-Print Network [OSTI]

WIND ENERGY Wind Energ. (2014) Published online in Wiley Online Library (wileyonlinelibrary Correspondence M. Wächter, ForWind-Center for Wind Energy Research, Institute of Physics, Carl Von Ossietzky on the operation of wind energy converters (WECs) imposing different risks especially in terms of highly dynamic

Peinke, Joachim

423

Wind Resource Map: Mexico | Open Energy Information  

Open Energy Info (EERE)

Wind Resource Map: Mexico Wind Resource Map: Mexico Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Wind Resource Map: Mexico Focus Area: Renewable Energy Topics: Potentials & Scenarios Website: www.altestore.com/howto/Reference-Materials/Wind-Resource-Map-Mexico/a Equivalent URI: cleanenergysolutions.org/content/wind-resource-map-mexico,http://clean Language: English Policies: Deployment Programs DeploymentPrograms: Technical Assistance This is on-shore wind resource map for rural power applications in Mexico. The map can be used to aid in appropriate siting of wind power installations. Please note that the wind speed classes are taken at 30 m (100 feet [ft]), instead of the usual 10 m (33 ft). Each wind power class should span two power densities. For example, Wind Power Class = 3

424

RELIABILITY OF WIND POWER FROM DISPERSED SITES: A PRELIMINARY ASSESSMENT  

E-Print Network [OSTI]

POWER FREQUENCY TO LOSS-OF-LOAD PROBABIL ITY The Basic Steps Optimization of Various Kinds WIND DATA

Kahn, E.

2011-01-01T23:59:59.000Z

425

wind energy  

National Nuclear Security Administration (NNSA)

5%2A en Pantex to Become Wind Energy Research Center http:nnsa.energy.govfieldofficesnponpopressreleasespantex-become-wind-energy-research-center

426

Plans for US wind tunnel set to take off  

Science Journals Connector (OSTI)

... world's largest and most sophisticated wind-tunnel complex, to be used by aircraft manufacturer Boeing to speed up the development of successors to the ... to speed up the development of successors to the Boeing 747 jumbo jet.

Colin Macilwain

1994-07-28T23:59:59.000Z

427

Offshore winds using remote sensing techniques  

Science Journals Connector (OSTI)

Ground-based remote sensing instruments can observe winds at different levels in the atmosphere where the wind characteristics change with height: the range of heights where modern turbine rotors are operating. A six-month wind assessment campaign has been made with a LiDAR (Light Detection And Ranging) and a SoDAR (Sound Detection and Ranging) on the transformer/platform of the world's largest offshore wind farm located at the West coast of Denmark to evaluate their ability to observe offshore winds. The high homogeneity and low turbulence levels registered allow the comparison of LiDAR and SoDAR with measurements from cups on masts surrounding the wind farm showing good agreement for both the mean wind speed and the longitudinal component of turbulence. An extension of mean wind speed profiles from cup measurements on masts with LiDAR observations results in a good match for the free sectors at different wind speeds. The log-linear profile is fitted to the extended profiles (averaged over all stabilities and roughness lengths) and the deviations are small. Extended profiles of turbulence intensity are also shown for different wind speeds up to 161 m. Friction velocities and roughness lengths calculated from the fitted log-linear profile are compared with the Charnock model which seems to overestimate the sea roughness for the free sectors.

Alfredo Peńa; Charlotte Bay Hasager; Sven-Erik Gryning; Michael Courtney; Ioannis Antoniou; Torben Mikkelsen; Paul Sřrensen

2007-01-01T23:59:59.000Z

428

Wind energy resource in Northern Mexico  

Science Journals Connector (OSTI)

Abstract Mexico has installed less wind power compared to the other North American countries. Renewable energy sources only account for 3% of the energy mix in Mexico. The U.S. states bordering Mexico, namely Texas, New Mexico, Arizona, and California, have good wind power resources. Among them, Texas has the highest installed wind power capacity of 10.34 GW. The wind resources in these bordering states indicate that the wind energy resource in Northern Mexico must be assessed; thus, the spatial and temporal information about the wind energy resource was studied. The daily pattern of the wind speed, one per state studied, was obtained. The wind speed was found to exhibit a pattern; it increases from 4 pm until 6 am the following day. The main conclusions are that the state of Tamaulipas has the highest Wind Power Density (WPD) of 1000 W/m2 during September and October, but the north of Nuevo Leon has, in a large part of its territory, an annual WPD greater than 103 W/m2; each state has 1700 useful hours of wind speed above 3 m/s. Northern Mexico has some zones with excellent wind speed as well; the states of Chihuahua, Coahuila, Nuevo Leon and Tamaulipas have a wind speed of over 4.51 m/s across nearly their entire territories. Because Mexico in recent years has been starting to exploit renewable energy sources, the government has mandated energy reform, which improves the conditions for investment in wind energy in Mexico.

Q. Hernández-Escobedo; R. Saldańa-Flores; E.R. Rodríguez-García; F. Manzano-Agugliaro

2014-01-01T23:59:59.000Z

429

Economical Aspects of Adjustable Speed Drives in Pumping Systems  

E-Print Network [OSTI]

Speed variations of pumps have become increasingly popular as the technology to produce variable frequency drives has progressed. Variable speed drives have many advantages compared to throttle valves when it comes to regulation of flow. They offer...

Hovstadius, G.

430

Review of Wind Energy Forecasting Methods for Modeling Ramping Events  

SciTech Connect (OSTI)

Tall onshore wind turbines, with hub heights between 80 m and 100 m, can extract large amounts of energy from the atmosphere since they generally encounter higher wind speeds, but they face challenges given the complexity of boundary layer flows. This complexity of the lowest layers of the atmosphere, where wind turbines reside, has made conventional modeling efforts less than ideal. To meet the nation's goal of increasing wind power into the U.S. electrical grid, the accuracy of wind power forecasts must be improved. In this report, the Lawrence Livermore National Laboratory, in collaboration with the University of Colorado at Boulder, University of California at Berkeley, and Colorado School of Mines, evaluates innovative approaches to forecasting sudden changes in wind speed or 'ramping events' at an onshore, multimegawatt wind farm. The forecast simulations are compared to observations of wind speed and direction from tall meteorological towers and a remote-sensing Sound Detection and Ranging (SODAR) instrument. Ramping events, i.e., sudden increases or decreases in wind speed and hence, power generated by a turbine, are especially problematic for wind farm operators. Sudden changes in wind speed or direction can lead to large power generation differences across a wind farm and are very difficult to predict with current forecasting tools. Here, we quantify the ability of three models, mesoscale WRF, WRF-LES, and PF.WRF, which vary in sophistication and required user expertise, to predict three ramping events at a North American wind farm.

Wharton, S; Lundquist, J K; Marjanovic, N; Williams, J L; Rhodes, M; Chow, T K; Maxwell, R

2011-03-28T23:59:59.000Z

431

Resonant Vibrations Resulting from the Re-Engineering of a Constant-Speed 2-Bladed Turbine to a Variable-Speed 3-Bladed Turbine  

SciTech Connect (OSTI)

The CART3 (Controls Advanced Research Turbine, 3-bladed) at the National Wind Technology Center has recently been converted from a 2-bladed constant speed machine to a 3-bladed variable speed machine designed specically for controls research. The purpose of this conversion was to develop an advanced controls field-testing platform which has the more typical 3-bladed configuration. A result of this conversion was the emergence of several resonant vibrations, some of which initially prevented operation of the turbine until they could be explained and resolved. In this paper, the investigations into these vibrations are presented as 'lessons-learned'. Additionally, a frequency-domain technique called waterfall plotting is discussed and its usefulness in this research is illustrated.

Fleming, P.; Wright, A. D.; Finersh, L. J.

2010-12-01T23:59:59.000Z

432

Abstract--The offshore wind farm with installed back-to-back power converter in wind turbines is studied. As an  

E-Print Network [OSTI]

Abstract--The offshore wind farm with installed back-to- back power converter in wind turbines is studied. As an example the Burbo Bank offshore wind farm with Siemens Wind Power wind turbines is taken installed in wind turbines are presented. Harmonic load flow analysis and impedance frequency

Bak, Claus Leth

433

Reverse power management in a wind diesel system with a battery energy storage  

Science Journals Connector (OSTI)

The subject of this paper is to present the modeling of a Wind Diesel Hybrid System (WDHS) comprising a Diesel Generator (DG), a Wind Turbine Generator (WTG), the consumer Load, a Ni–Cd Battery based Energy Storage System (BESS) and a Distributed Control System (DCS). All the models of the previously mentioned components are presented and the performance of the WDHS is tested through simulation. Simulation results with graphs for frequency and voltage of the isolated power system, active powers generated/absorbed by the different elements and the battery voltage/current/state of charge are presented for negative load and wind speed steps. The negative load step reduces the load consumed power to a level less than the WTG produced power, so that to balance active powers a negative DG power is needed (DG reverse power). As the DG speed governor cannot control system frequency in a DG reserve power situation, it is shown how the DCS orders the BESS to load artificially the system until the DG power falls in a positive power interval. The negative wind step decreases the WTG produced power, returning the power system to a situation where the needed DG power returns to positive, so that the BESS is not needed to load the system.

R. Sebastián

2013-01-01T23:59:59.000Z

434

Towers for Offshore Wind Turbines  

Science Journals Connector (OSTI)

Increasing energy demand coupled with pollution free production of energy has found a viable solution in wind energy. Land based windmills have been utilized for power generation for more than two thousand years. In modern times wind generated power has become popular in many countries. Offshore wind turbines are being used in a number of countries to tap the energy from wind over the oceans and convert to electric energy. The advantages of offshore wind turbines as compared to land are that offshore winds flow at higher speed than onshore winds and the more available space. In some land based settings for better efficiency turbines are separated as much as 10 rotor diameters from each other. In offshore applications where only two wind directions are likely to predominate the distances between the turbines arranged in a line can be shortened to as little as two or four rotor diameters. Today more than a dozen offshore European wind facilities with turbine ratings of 450 kw to 3.6 MW exist offshore in very shallow waters of 5 to 12 m. Compared to onshore wind turbines offshore wind turbines are bigger and the tower height in offshore are in the range of 60 to 80 m. The water depths in oceans where offshore turbines can be located are within 30 m. However as the distance from land increases the costs of building and maintaining the turbines and transmitting the power back to shore also increase sharply. The objective of this paper is to review the parameters of design for the maximum efficiency of offshore wind turbines and to develop types offshore towers to support the wind turbines. The methodology of design of offshore towers to support the wind turbine would be given and the environmental loads for the design of the towers would be calculated for specific cases. The marine corrosion on the towers and the methods to control the corrosion also would be briefly presented. As the wind speeds tend to increase with distance from the shore turbines build father offshore will be able to capture more wind energy. Currently two types of towers are considered. Cylindrical tubular structures and truss type structures. But truss type structures have less weight and flexibility in design. The construction of the offshore towers to harness the wind energy is also presented. The results will include the calculation of wind and wave forces on the tower and the design details for the tower.

V. J. Kurian; S. P. Narayanan; C. Ganapathy

2010-01-01T23:59:59.000Z

435

915-MHz Radar Wind Profiler (915RWP) Handbook  

SciTech Connect (OSTI)

The 915 MHz radar wind profiler/radio acoustic sounding system (RWP/RASS) measures wind profiles and backscattered signal strength between (nominally) 0.1 km and 5 km and virtual temperature profiles between 0.1 km and 2.5 km. It operates by transmitting electromagnetic energy into the atmosphere and measuring the strength and frequency of backscattered energy. Virtual temperatures are recovered by transmitting an acoustic signal vertically and measuring the electromagnetic energy scattered from the acoustic wavefront. Because the propagation speed of the acoustic wave is proportional to the square root of the virtual temperature of the air, the virtual temperature can be recovered by measuring the Doppler shift of the scattered electromagnetic wave.

Coulter, R

2005-01-01T23:59:59.000Z

436

This document will help you understand the statistics commonly used to describe wind when it is studied  

E-Print Network [OSTI]

Resource Assessment Wind Data Permitting Case Studies 1. 2. 3. 4. 5. 6. 7. Wind Statistics 6 Inside this Edition: Wind Data Overview p. 1 Wind Statistics p. 1 Graphs p. 2 For more information p. 2 Wind speedsThis document will help you understand the statistics commonly used to describe wind when

Massachusetts at Amherst, University of

437

The Inside of a Wind Turbine | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

The Inside of a Wind Turbine The Inside of a Wind Turbine The Inside of a Wind Turbine 1 of 17 Tower: 2 of 17 Tower: Made from tubular steel (shown here), concrete, or steel lattice. Supports the structure of the turbine. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity. Generator: 3 of 17 Generator: Produces 60-cycle AC electricity; it is usually an off-the-shelf induction generator. High-speed shaft: 4 of 17 High-speed shaft: Drives the generator. Nacelle: 5 of 17 Nacelle: Sits atop the tower and contains the gear box, low- and high-speed shafts, generator, controller, and brake. Some nacelles are large enough for a helicopter to land on. Wind vane: 6 of 17 Wind vane: Measures wind direction and communicates with the yaw drive to orient the

438

Wind Energy  

Broader source: Energy.gov (indexed) [DOE]

FUPWG Meeting FUPWG Meeting NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy operated by the Alliance for Sustainable Energy, LLC Robi Robichaud November 18, 2009 Topics Introduction Review of the Current Wind Market Drivers for Wind Development Siting g Issues Wind Resource Assessment Wind Characteristics Wind Power Potential Basic Wind Turbine Theory Basic Wind Turbine Theory Types of Wind Turbines Facts About Wind Siting Facts About Wind Siting Wind Performance 1. United States: MW 1 9 8 2 1 9 8 3 1 9 8 4 1 9 8 5 1 9 8 6 1 9 8 7 1 9 8 8 1 9 8 9 1 9 9 0 1 9 9 1 1 9 9 2 1 9 9 3 1 9 9 4 1 9 9 5 1 9 9 6 1 9 9 7 1 9 9 8 1 9 9 9 2 0 0 0 2 0 0 1 2 0 0 2 2 0 0 3 2 0 0 4 2 0 0 5 2 0 0 6 2 0 0 7 2 0 0 8 Current Status of the Wind Industry Total Global Installed Wind Capacity Total Global Installed Wind Capacity Total Global Installed Wind Capacity

439

Offshore Wind Potential Tables  

Wind Powering America (EERE)

Offshore wind resource by state and wind speed interval within 50 nm of shore. Offshore wind resource by state and wind speed interval within 50 nm of shore. Wind Speed at 90 m (m/s) 7.0 - 7.5 7.5 - 8.0 8.0 - 8.5 8.5 - 9.0 9.0 - 9.5 9.5 - 10.0 >10.0 Total >7.0 State Area km 2 (MW) Area km 2 (MW) Area km 2 (MW) Area km 2 (MW) Area km 2 (MW) Area km 2 (MW) Area km 2 (MW) Area km 2 (MW) California 11,439 (57,195) 24,864 (124,318) 23,059 (115,296) 22,852 (114,258) 13,185 (65,924) 15,231 (76,153) 6,926 (34,629) 117,555 (587,773) Connecticut 530 (2,652) 702 (3,508) 40 (201) 0 (0) 0 (0) 0 (0) 0 (0) 1,272 (6,360) Delaware 223 (1,116) 724 (3,618) 1,062 (5,310) 931 (4,657) 0 (0) 0 (0) 0 (0) 2,940 (14,701) Georgia 3,820 (19,102) 7,741 (38,706) 523 (2,617) 0 (0) 0 (0) 0 (0) 0 (0) 12,085 (60,425) Hawaii 18,873 (94,363) 42,298 (211,492)

440

Systems Performance Analyses of Alaska Wind-Diesel Projects; Kotzebue, Alaska (Fact Sheet)  

SciTech Connect (OSTI)

This fact sheet summarizes a systems performance analysis of the wind-diesel project in Kotzebue, Alaska. Data provided for this project include wind turbine output, average wind speed, average net capacity factor, and optimal net capacity factor based on Alaska Energy Authority wind data, estimated fuel savings, and wind system availability.

Baring-Gould, I.

2009-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Impact of DFIG wind turbines on transient stability of power systems a review  

E-Print Network [OSTI]

Impact of DFIG wind turbines on transient stability of power systems ­ a review Authors Na Abstract of wind farms are using variable speed wind turbines equipped with doubly-fed induction generators (DFIG) due to their advantages over other wind turbine generators. Therefore, the analysis of wind power

Pota, Himanshu Roy

442

Short-term Wind Power Forecasting Using Advanced Statistical T.S. Nielsen1  

E-Print Network [OSTI]

Short-term Wind Power Forecasting Using Advanced Statistical Methods T.S. Nielsen1 , H. Madsen1 , H considered in the ANEMOS project for short-term fore- casting of wind power. The total procedure typically in for prediction of wind power or wind speed, estimating the uncertainty of the wind power forecast, and finally

Paris-Sud XI, Université de

443

Abstract--This paper addresses the problem of controlling wind energy conversion systems (WECS) which involve  

E-Print Network [OSTI]

Abstract-- This paper addresses the problem of controlling wind energy conversion systems (WECS-inverter. The goal of control is to maximize wind energy extraction and this needs letting the wind turbine rotor wind energy extraction) only for one wind speed value depending on the considered value of turbine

Paris-Sud XI, Université de

444

Prediction, operations, and condition monitoring in wind energy Andrew Kusiak a,*, Zijun Zhang b  

E-Print Network [OSTI]

Review Prediction, operations, and condition monitoring in wind energy Andrew Kusiak a,*, Zijun 2013 Available online 23 August 2013 Keywords: Wind energy Wind speed prediction Wind turbine control Condition monitoring and fault detection a b s t r a c t Recent developments in wind energy research

Kusiak, Andrew

445

The Use of Tall Tower Field Data for Estimating Wind Turbine Power Performance , J. Chapman1  

E-Print Network [OSTI]

The Use of Tall Tower Field Data for Estimating Wind Turbine Power Performance A. Swift1 , J wind speed measurements on the TTU WISE 200m and 78m towers. A hypothetical wind turbine is shown. At potential wind turbine sites, it is uncommon to have wind measurements available at multiple heights. Then

Manuel, Lance

446

RAIN AND WIND ESTIMATION FROM SEAWINDS IN HURRICANES AT ULTRA HIGH RESOLUTION  

E-Print Network [OSTI]

function (GMF) which relates wind to backscatter (0 ) is not well understood for extremely high wind speedsRAIN AND WIND ESTIMATION FROM SEAWINDS IN HURRICANES AT ULTRA HIGH RESOLUTION Brent A. Williams method for estimating wind and rain in hurricanes from SeaWinds at ultra-high resolution is developed. We

Long, David G.

447

NIST BUILDING SCIENCE SERIES 180 Database-Assisted Design for Wind  

E-Print Network [OSTI]

climatological information on extreme wind speeds and their direction-dependence can be used in conjunction; aerodynamics; extreme winds; database-assisted design; structural dynamics; wind directionality; wind forcesNIST BUILDING SCIENCE SERIES 180 Database-Assisted Design for Wind: Concepts, Software

448

Performance of a stand-alone wind-electric ice maker for remote villages  

SciTech Connect (OSTI)

Two ice makers in the 1.1 metric tons per 24 hours (1.2 tons per day) size range were tested to determine their performance when directly coupled to a variable-frequency wind turbine generator. Initial tests were conducted using a dynamometer to simulate to wind to evaluate whether previously determined potential problems were significant and to define basic performance parameters. Field testing in Norman, Oklahoma, was completed to determine the performance of one of the ice makers under real wind conditions. As expected, the ice makers produced more ice at a higher speed than rated, and less ice at a lower speed. Due to the large start-up torque requirement of reciprocating compressors, the ice making system experienced a large start-up current and corresponding voltage drop which required a larger wind turbine that expected to provide the necessary current and voltage. Performance curves for ice production and power consumption are presented. A spreadsheet model was constructed to predict ice production at a user-defined site given the wind conditions for that location. Future work should include long-term performance tests and research on reducing the large start-up currents the system experiences when first coming on line.

Davis, H.C. [National Renewable Energy Lab., Golden, CO (United States); Brandemuehl, M.J. [University of Colorado, Boulder, CO (United States). Joint Center for Energy Management; Bergey, M.L.S. [Bergey Windpower Co., Norman, OK (United States)

1995-01-01T23:59:59.000Z

449

NREL: Wind Research - Research Staff Biographies  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and Eduard Muljadi on a soon-to-be-published history of Variable-Speed Operation of Wind Turbines. Photo of Corrie Christol Corrie Christol Administrative Project Manager, National...

450

Energy Analysis of Convectively Induced Wind Perturbations  

Science Journals Connector (OSTI)

Budgets of divergent and rotational components of kinetic energy (KD and KR) are examined for four upper level wind speed maxima that develop during the fourth Atmospheric Variability Experiment (AVE IV) and the first AVE-Severe Environmental ...

Henry E. Fuelberg; Dennis E. Buechler

1989-04-01T23:59:59.000Z

451

Power Performance Measurements of the NREL CART-2 Wind Turbine Using a Nacelle-Based Lidar Scanner  

Science Journals Connector (OSTI)

Different certification procedures in wind energy, such as power performance testing or load estimation, require measurements of the wind speed, which is set in relation to the electrical power output or the turbine loading. The wind shear affects ...

Andreas Rettenmeier; David Schlipf; Ines Würth; Po Wen Cheng

2014-10-01T23:59:59.000Z

452

Study of Stability Analysis of a Grid-Connected Doubly Fed Induction Generator (DFIG)-based small Wind Farm.  

E-Print Network [OSTI]

??Wind is the most reliable, clean and fast-developing renewable energy source. The DFIG-based variable speed wind turbine system is now the most popular in wind… (more)

Dhar, Baishakhi

2013-01-01T23:59:59.000Z

453

Assessing the Impacts of Reduced Noise Operations of Wind Turbines on Neighbor Annoyance: A Preliminary Analysis in Vinalhaven, Maine  

E-Print Network [OSTI]

of Reduced Noise Operations of Wind Turbines on Neighborof Reduced Noise Operations of Wind Turbines on NeighborWind Speed (m/s) 3 Turbines (in operation at the time) Noise

Hoen, Ben

2010-01-01T23:59:59.000Z

454

Q. J. R. Meteorol. Soc. (2004), 130, pp. 120 Using mesocale model winds for correcting wind-drift errors in radar  

E-Print Network [OSTI]

the vertical shear of the horizontal wind. We assume the shear and the fall speed in the layer are constant rain because of the low fall speed of around 1 m s-1. Sampling these wind-induced fall streak patterns vertical profile of reflectivity shear fall streak wind drift 1. Introduction Operational radars around

Reading, University of

455

Wind extremes in the North Sea Basin under climate change: An ensemble study of 12 CMIP5 GCMs  

E-Print Network [OSTI]

Wind extremes in the North Sea Basin under climate change: An ensemble study of 12 CMIP5 GCMs R. C levels and waves are generated by low atmospheric pressure and severe wind speeds during storm events. As a result of the geometry of the North Sea, not only the maximum wind speed is relevant, but also wind

Haak, Hein

456

Wind Mills  

Science Journals Connector (OSTI)

Over 5,000 years ago, the ancient Egyptians used wind to sail ships on the Nile River. While the proliferation of water mills was in full swing, windmills appeared to harness more inanimate energy by employing wind

J. S. Rao

2011-01-01T23:59:59.000Z

457

Wind Farm  

Office of Energy Efficiency and Renewable Energy (EERE)

The wind farm in Greensburg, Kansas, was completed in spring 2010, and consists of ten 1.25 megawatt (MW) wind turbines that supply enough electricity to power every house, business, and municipal...

458

Wind Power  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Wind Power As the accompanying map of New Mexico shows, the best wind power generation potential near WIPP is along the Delaware Mountain ridge line of the southern Guadalupe...

459

Wind Power  

Science Journals Connector (OSTI)

For off-shore wind energy, it is not economically profitable to locate wind turbines in waters with depths larger than about 40 m. For this reason, some floating turbine prototypes are being tested, which can be ...

Ricardo Guerrero-Lemus; José Manuel Martínez-Duart

2013-01-01T23:59:59.000Z

460

Modeling and Simulation of Wind Shear and Tower Shadow on Wind Turbines  

Science Journals Connector (OSTI)

Abstract This paper focuses on the modeling and simulation in Matlab/Simulink of the effects of wind shear and tower shadow in a three bladed, variable-speed wind turbine system. The study of the mechanical stress, the mitigation of the torque oscillations and the improvement of the aerodynamic efficiency below rated wind speed, can be attained with a proper modeling of the turbine system. This paper is a contribution on the study of the effects of wind shear and tower shadow, often approximated or neglected, that have to be properly understood, considered and modeled in order to get a better performance of the turbine system.

H. Sintra; V.M.F. Mendes; R. Melício

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Multi-frequency observations of SNR J0453-6829 in the LMC; A composite supernova remnant with a pulsar wind nebula  

E-Print Network [OSTI]

The Large Magellanic Cloud (LMC) is rich in supernova remnants (SNRs) which can be investigated in detail with radio, optical and X-ray observations. SNR J0453-6829 is an X-ray and radio-bright remnant in the LMC, within which previous studies revealed the presence of a pulsar wind nebula (PWN), making it one of the most interesting SNRs in the Local Group of galaxies. We study the emission of SNR J0453-6829 to improve our understanding of its morphology, spectrum, and thus the emission mechanisms in the shell and the PWN of the remnant. We obtained new radio data with the Australia Telescope Compact Array and analysed archival XMM-Newton observations of SNR J0453-6829. We studied the morphology of SNR J0453-6829 from radio, optical and X-ray images and investigated the energy spectra in the different parts of the remnant. Our radio results confirm that this LMC SNR hosts a typical PWN. The prominent central core of the PWN exhibits a radio spectral index alpha_Core of -0.04+/-0.04, while in the rest of the S...

Haberl, F; Bozzetto, L M; Crawford, E J; Points, S D; Pietsch, W; De Horta, A Y; Tothill, N; Payne, J L; Sasaki, M

2012-01-01T23:59:59.000Z

462

QUIKSCAT MEASUREMENTS AND ECMWF WIND FORECASTS  

E-Print Network [OSTI]

. (2004) this forecast error was encountered when assimilating satellite measurements of zonal wind speeds between satellite measurements and meteorological forecasts of near-surface ocean winds. This type of covariance enters in assimilation techniques such as Kalman filtering. In all, six residual fields

Malmberg, Anders

463

QUIKSCAT MEASUREMENTS AND ECMWF WIND FORECASTS  

E-Print Network [OSTI]

. (2004) this forecast error was encountered when assimilating satellite measurements of zonal wind speeds between satellite measurements and meteorological forecasts of near­surface ocean winds. This type of covariance enters in assimilation techniques such as Kalman filtering. In all, six residual fields

Malmberg, Anders

464

Wind energy  

Science Journals Connector (OSTI)

...is approximately 4.5-6.01 for onshore wind farms. The price for offshore wind farms is estimated to be 50% higher. For comparison...visually intrusive. The visual impact of offshore wind farms quickly diminishes with distance and 10km...

2007-01-01T23:59:59.000Z

465

‘Chinook winds.’  

Science Journals Connector (OSTI)

...of south-easterly winds, which blow over the...Ocean, from which the winds come, can at this season...freezing-point. The wind well known in the Alps as the foehn is another example of...result is complicated by local details; regions of...

George M. Dawson

1886-01-08T23:59:59.000Z

466

Dynamic Analysis of Wind Turbine Planetary Gears Using an Extended Harmonic Balance Approach: Preprint  

SciTech Connect (OSTI)

The dynamics of wind turbine planetary gears with gravity effects are investigated using an extended harmonic balance method that extends established harmonic balance formulations to include simultaneous internal and external excitations. The extended harmonic balance method with arc-length continuation and Floquet theory is applied to a lumped-parameter planetary gear model including gravity, fluctuating mesh stiffness, bearing clearance, and nonlinear tooth contact to obtain the planetary gear dynamic response. The calculated responses compare well with time domain integrated mathematical models and experimental results. Gravity is a fundamental vibration source in wind turbine planetary gears and plays an important role in system dynamics, causing hardening effects induced by tooth wedging and bearing-raceway contacts. Bearing clearance significantly reduces the lowest resonant frequencies of translational modes. Gravity and bearing clearance together lowers the speed at which tooth wedging occurs lower than the resonant frequency.

Guo, Y.; Keller, J.; Parker, R. G.

2012-06-01T23:59:59.000Z

467

MHL High Speed Cavitation | Open Energy Information  

Open Energy Info (EERE)

High Speed Cavitation High Speed Cavitation Jump to: navigation, search Basic Specifications Facility Name MHL High Speed Cavitation Overseeing Organization University of Michigan Hydrodynamics Hydrodynamic Testing Facility Type Channel Length(m) 0.8 Beam(m) 0.2 Depth(m) 0.2 Cost(per day) $2000(+ Labor/Materials) Towing Capabilities Towing Capabilities Yes Maximum Velocity(m/s) 25.9 Wavemaking Capabilities Wavemaking Capabilities None Channel/Tunnel/Flume Channel/Tunnel/Flume Yes Velocity(m/s) 25.9 Recirculating No Wind Capabilities Wind Capabilities None Control and Data Acquisition Description Custom Data Acquisition System using National Instruments hardware; system compatible with Planing Hull and Floating Beam Dynamometers Number of channels 16 Bandwidth(kHz) 20 Cameras Yes

468

Saturation wind power potential and its implications for wind energy  

Science Journals Connector (OSTI)

...model layer that intersects the turbine rotor. The kinetic energy reduction is translated into a wind speed reduction. The resulting...Jacobson MZ (2010) Short-term effects of controlling fossil-fuel soot, biofuel soot and gases, and methane on climate, Arctic...

Mark Z. Jacobson; Cristina L. Archer

2012-01-01T23:59:59.000Z

469

Network Wind Power Over the Pacific Northwest. Progress Report, October 1979-September 1980.  

SciTech Connect (OSTI)

The research in FY80 is composed of six primary tasks. These tasks include data collection and analysis, wind flow studies around an operational wind turbine generator (WTG), kite anemometer calibration, wind flow analysis and prediction, the Klickitat County small wind energy conversion system (SWECS) program, and network wind power analysis. The data collection and analysis task consists of four sections, three of which deal with wind flow site surveys and the fourth with collecting and analyzing wind data from existing data stations. This report also includes an appendix which contains mean monthly wind speed data summaries, wind spectrum summaries, time series analysis plots, and high wind summaries.

Baker, Robert W.; Hewson, E. Wendell

1980-10-01T23:59:59.000Z

470

Weather pattern climatology of the Great Plains and the related wind regime  

SciTech Connect (OSTI)

The meteorology of the Great Plains can be described as a constant progression of air masses, fronts and cyclonic storm systems. Each of these meteorological conditions can be characterized by identifiable isobaric and related weather parameter patterns. Nine such patterns have been defined to type the weather patterns in the Great Plains. Time series of weather pattern types were produced for 62 stations on the Great Plains. Statistical analyses of these time series produced annual and seasonal frequencies of occurrence of the weather pattern types. Maps of the annual and seasonal frequency of occurrence of weather pattern type are presented for the Great Plains. Persistence and alternation frequencies match what is expected for traveling temperate latitude cyclones, anticyclones and fronts. The wind regime for stations at which the anemometer height and location was constant (and known) for a minimum of three consecutive years was stratified by weather pattern type. Statistical analyses were made to show the response of the wind to the large-scale distribution of air pressure associated with a weather pattern type. The response of the wind to the weather pattern is a site-specific result of the interaction of the large-scale meteorology with local terrain, surface roughness and atmospheric stability. Mean wind speed discriminates between pairs of weather pattern types with better than 75% confidence for more than two-thirds of the possible pairs of weather pattern types.

Barchet, W.R.

1982-11-01T23:59:59.000Z

471

Effect of Forced Excitation on Wind Turbine with Dynamic Analysis in Deep Offshore Wind in Addition to Japanese Status of Offshore Projects  

Science Journals Connector (OSTI)

In this paper, we tried to estimate the effect of control method on floating offshore wind turbine. The experiment in the water basin revealed that traditional blade pitch control can amplify the platform pitch oscillation of floating wind turbine. In order to understand the physical phenomenon, we used aeroelastic simulation using GH Bladed. Turbine model is based on the turbine used in wind tunnel test. To simulate the pitching motion of floating platform, we used onshore wind turbine model with inflow with oscillating wind speed that simulates relative wind speed change from wind turbine's fore-aft pitching motion. Two types of control method are used; fixed pitch variable speed control which represents before rated state of large wind turbines and variable pitch variable speed control which represents over rated state of large wind turbines. Comparing the relation between wind speed change and rotor thrust force change of two control methods, we made it clear that traditional blade pitch control method make thrust force change almost the inverse of wind speed increase and decrease. From thrust force inverse to wind speed change, tower pitching motion can be amplified. That is, blade pitch control can induce negative damping on tower pitching motion. As a conclusion pitch control can increase larger blade load although pitch control aims to reduce the blade load.

Mitsumasa Iino; Toshiki Chujo; Makoto Iida; Chuichi Arakawa

2012-01-01T23:59:59.000Z

472

Sustainably Priced Energy Enterprise Development (SPEED) Goals | Department  

Broader source: Energy.gov (indexed) [DOE]

Sustainably Priced Energy Enterprise Development (SPEED) Goals Sustainably Priced Energy Enterprise Development (SPEED) Goals Sustainably Priced Energy Enterprise Development (SPEED) Goals < Back Eligibility Investor-Owned Utility Municipal Utility Rural Electric Cooperative Savings Category Bioenergy Alternative Fuel Vehicles Hydrogen & Fuel Cells Buying & Making Electricity Water Solar Heating & Cooling Water Heating Wind Program Info State Vermont Program Type Renewables Portfolio Standard Provider Vermont Public Service Board Vermont's Sustainably Priced Energy Enterprise Development (SPEED) Program was created by legislation in 2005 to promote renewable energy development. The SPEED program itself is not a renewable portfolio goal or standard. However, if the Vermont Public Service Board (PSB) determines that the

473

Quality Control and Verification of Weather Radar Wind Profiles IWAN HOLLEMAN  

E-Print Network [OSTI]

- tions of the vertical velocity, which is a sum of the vertical wind velocity and the hydrometeor fall. 1986). Profiles of wind speed and direction, hydrometeor fall speed, and divergence have been obtainedQuality Control and Verification of Weather Radar Wind Profiles IWAN HOLLEMAN Royal Netherlands

Stoffelen, Ad

474

Upper Ocean Response to Tropical Cyclone Wind Asymmetries S. Daniel Jacob and Lynn K. Shay  

E-Print Network [OSTI]

High Resolution Radiometer (AVHRR) images of SST. As a storm intensifies, the increasing wind speed may. However, the significant SST reduction induced by the increasing wind speed leads to reduced air to the atmosphere ( 20%) and vertical mixing at the base of the oceanic mixed layer ( 80%) induced by wind stress

Shay, Lynn K. "Nick"

475

Quantifying Errors Associated with Satellite Sampling of Offshore Wind S.C. Pryor1,2  

E-Print Network [OSTI]

1 Quantifying Errors Associated with Satellite Sampling of Offshore Wind Speeds S.C. Pryor1,2 , R farm. However, there are a number of biases inherent in satellite retrieval of wind speeds which wind farms speculative. Here we quantify these biases and derive theoretical and empirical estimates

476

Discrepancies in the Prediction of Solar Wind using Potential Field Source Surface Model: An  

E-Print Network [OSTI]

expansion near the Sun and the solar wind speed observed at earth was first noted by Levine, AltschulerDiscrepancies in the Prediction of Solar Wind using Potential Field Source Surface Model between the magnetic flux tube expansion factor (FTE) at the source surface and the solar wind speed

Zhao, Xuepu

477

On the limiting aerodynamic roughness of the ocean in very strong winds  

E-Print Network [OSTI]

On the limiting aerodynamic roughness of the ocean in very strong winds M. A. Donelan,1 B. K. Haus January 2004; accepted 13 August 2004; published 28 September 2004. [1] The aerodynamic friction between, the ``aerodynamic roughness'') increases with the wind speed. Can one merely extrapolate this wind speed tendency

Saltzman, Eric

478

Comparison of Wake Model Simulations with Offshore Wind Turbine Wake Profiles Measured by Sodar  

Science Journals Connector (OSTI)

This paper gives an evaluation of most of the commonly used models for predicting wind speed decrease (wake) downstream of a wind turbine. The evaluation is based on six experiments where free-stream and wake wind speed profiles were measured ...

R. J. Barthelmie; G. C. Larsen; S. T. Frandsen; L. Folkerts; K. Rados; S. C. Pryor; B. Lange; G. Schepers

2006-07-01T23:59:59.000Z

479

Wind Blog  

Broader source: Energy.gov (indexed) [DOE]

wind-blog Office of Energy Efficiency & Renewable wind-blog Office of Energy Efficiency & Renewable Energy Forrestal Building 1000 Independence Avenue, SW Washington, DC 20585 en Two Facilities, One Goal: Advancing America's Wind Industry http://energy.gov/eere/articles/two-facilities-one-goal-advancing-america-s-wind-industry wind-industry" class="title-link">Two Facilities, One Goal: Advancing America's Wind Industry

480

Guide to Using the WIND Toolkit Validation Code  

SciTech Connect (OSTI)

In response to the U.S. Department of Energy's goal of using 20% wind energy by 2030, the Wind Integration National Dataset (WIND) Toolkit was created to provide information on wind speed, wind direction, temperature, surface air pressure, and air density on more than 126,000 locations across the United States from 2007 to 2013. The numerical weather prediction model output, gridded at 2-km and at a 5-minute resolution, was further converted to detail the wind power production time series of existing and potential wind facility sites. For users of the dataset it is important that the information presented in the WIND Toolkit is accurate and that errors are known, as then corrective steps can be taken. Therefore, we provide validation code written in R that will be made public to provide users with tools to validate data of their own locations. Validation is based on statistical analyses of wind speed, using error metrics such as bias, root-mean-square error, centered root-mean-square error, mean absolute error, and percent error. Plots of diurnal cycles, annual cycles, wind roses, histograms of wind speed, and quantile-quantile plots are created to visualize how well observational data compares to model data. Ideally, validation will confirm beneficial locations to utilize wind energy and encourage regional wind integration studies using the WIND Toolkit.

Lieberman-Cribbin, W.; Draxl, C.; Clifton, A.

2014-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency wind speed" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

An overview on doubly fed induction generators? controls and contributions to wind based electricity generation  

Science Journals Connector (OSTI)

Abstract Undoubtedly, energy has a significant role in economic growth and technical developments. Renewable energy resources are becoming more important in recent years due to their tremendous contributions to the independence of power generation industry from traditional fossil energy resources. Wind energy has been outstanding among renewable energy resources since continuous harvestable potential on the earth is approximately around 106 MW. Concerning the variable nature of wind energy, the variable speed machines, especially doubly fed induction generators (DFIG) are one of the considerations for wind energy conversion systems (WECS). Their implementation in renewable energy conversion systems is dramatically increasing due to their numerous advantages such as low cost and small size, the elimination of external DC source, the ability to produce maximum power under various wind and rotational speeds, the capability of controlling active and reactive power, and the opportunity to employ cheaper and smaller convertors and controllers. This paper is an extensive review of researches in the past 30 years on DFIG. The study starts with describing general perspective on wind energy and commonly used generators in wind conversion. Then it presents more details on \\{DFIGs\\} operational modes, utilizations, their modeling and simulation. It is followed by DFIG control methods and overviews of different employed electrical and mechanical controlling methods. Finally the review on the mutual impact of DFIG on power networks and vice versa, including wind uncertainty, power and frequency stability, power and voltage quality, operation under steady state, dynamic and fault conditions, and protections is given. Based on the review DFIG has advantages in terms of electrical, mechanical, and economic perspectives. It can be concluded that the DFIG has the most promising future for \\{WECSs\\} in power generation to complement the conventional systems.

Abdullah Asuhaimi B. Mohd Zin; Mahmoud Pesaran H.A.; Azhar B. Khairuddin; Leila Jahanshaloo; Omid Shariati

2013-01-01T23:59:59.000Z

482

Maximum power tracking control scheme for wind generator systems  

E-Print Network [OSTI]

The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor...

Mena, Hugo Eduardo

2009-05-15T23:59:59.000Z

483

Maximum power tracking control scheme for wind generator systems  

E-Print Network [OSTI]

The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor...

Mena Lopez, Hugo Eduardo

2008-10-10T23:59:59.000Z

484

Control of Wind Turbines for Power Regulation and  

E-Print Network [OSTI]

Control of Wind Turbines for Power Regulation and Load Reduction Juan Jose Garcia Quirante Kongens regulation and load reduction and their ensemble in a variable-speed wind turbine. The power regulation aspects of mathematical modelling of wind turbines, and especially the control methods suited for power

485

Taming Hurricanes With Arrays of Offshore Wind Turbines  

E-Print Network [OSTI]

Taming Hurricanes With Arrays of Offshore Wind Turbines Mark Z. Jacobson Cristina Archer, Willet #12;Representation of a vertically-resolved wind turbine in model Lines are model layers) or 50 m/s (destruction) speed. Can Walls of Offshore Wind Turbines Dissipate Hurricanes? #12;Katrina

Firestone, Jeremy

486

NACA0015 Measurements in LM Wind Tunnel and Turbulence  

E-Print Network [OSTI]

NACA0015 Measurements in LM Wind Tunnel and Turbulence Generated Noise Franck Bertagnolio Risø, Denmark November 2008 #12;Author: Franck Bertagnolio Title: NACA0015 Measurements in LM Wind Tunnel on its surface and measured in the wind tunnel at LM Glasfiber at various inflow speeds, angles of attack

487

Ris-PhD-Report Complex Terrain and Wind Lidars  

E-Print Network [OSTI]

calculations over the same terrains. The lidar performance was also simulated with the commercial software WAs;#12;Author: Ferhat Bingöl Title: Complex terrain and wind lidars Division: Wind Energy Division Risø-PhD-52 and the comparison of the measurement data with the flow model outputs showed that the mean wind speed calculated

488

SODAR Wind Resource Measurement Results at Falmouth, MA Prepared for  

E-Print Network [OSTI]

of Massachusetts at Amherst. The data were collected to estimate the wind resource for possible wind turbines to well over 100 m. The operation of a SODAR and the SODAR data are described in this report. SODAR Technology The UMass ART VT-1 SODAR measures wind speed and direction at multiple heights using an acoustic

Massachusetts at Amherst, University of

489

The Solar Wind, CMEs and the Origins of Heliospheric Activity  

E-Print Network [OSTI]

release o Coronal holes o Source of high-speed solar wind #12;peter.gallagher@tcd.ie #12;#12;peter Parker => Parker Spiral: r - r0 = -(v/ )( - 0) o Winding angle: o Inclined at ~45Âş at 1 AU and ~90Âş by 10The Solar Wind, CMEs and the Origins of Heliospheric Activity Peter T. Gallagher School of Physics

490

Description and Simulation of Gust Front Wind Field Lijuan Wanga  

E-Print Network [OSTI]

-stationarity of the wind field associated with these extreme events poses serious challenges in their modelingDescription and Simulation of Gust Front Wind Field Lijuan Wanga , Ahsan Kareemb a Nat front wind field is proposed based on the time-frequency description of the wind field. Traditionally

Kareem, Ahsan

491

Wind tunnel simulation of wind effect on a group of high Cooling towers  

Science Journals Connector (OSTI)

Aerodynamic interference between high cooling towers in the atmospheric boundary layer (ABL) and uniform flow has been discussed. For the 1/1000 ABL model set up in the 2.25m low speed wind tunnel at Peking Unive...

Yan Dachun; Li Chenxin

1987-02-01T23:59:59.000Z

492

Light Properties Light travels at the speed of light `c'  

E-Print Network [OSTI]

LIGHT!! #12;Light Properties Light travels at the speed of light `c' C = 3 x 108 m/s Or 190.nasa.gov #12;The speed of light The speed of light `c' is equal to the frequency ` times the wavelength,000 miles/second!! Light could travel around the world about 8 times in one second #12;What is light?? Light

Mojzsis, Stephen J.

493

Numerical Simulation of the Irish Wind Climate and Comparison with Wind  

Open Energy Info (EERE)

Numerical Simulation of the Irish Wind Climate and Comparison with Wind Numerical Simulation of the Irish Wind Climate and Comparison with Wind Atlas Data Dataset Summary Description (Abstract): The wind climate of Ireland has been calculated using the Karlsruhe Atmospheric Mesoscale Model KAMM using the statistical-dynamical method. The large-scale climatology is represented by 65 classes of geostropic wind. From the frequency of the classes and the simulations the climatology of the surface wind is determined. The simulated winds are processed similar to observed data to obtain LIB-files for the Wind Atlas Analysis and Application Program WAsP. Comparisons are made with mast observations which have been analyzed by WAsP. Sites with high wind power potential are well predicted. Stations with low power are over predicted. (Purpose): Article describing an example of a KAMM

494

Turbine set with a generator feeding a network of constant frequency  

SciTech Connect (OSTI)

In a turbine set with an axial flow which is traversed by water and which is coupled to a generator feeding a network of constant frequency, the flow turbine is a propeller turbine with nonadjustable blades. The stator winding of the generator is connected to the network by means of a frequency-controllable converter, in particular a direct converter. The speed of rotation of the turbine set is controllable continuously according to the power to be delivered. In the case of an asynchronous design of the generator, it is advisable to provide the stator with a waterproof jacket on the inside and to flange it into the turbine tube, since the rotor with its cage winding is swept by water.

Spirk, F.

1983-01-11T23:59:59.000Z

495

Performance Indicators of Wind Energy Production  

E-Print Network [OSTI]

Modeling wind speed is one of the key element when dealing with the production of energy through wind turbines. A good model can be used for forecasting, site evaluation, turbines design and many other purposes. In this work we are interested in the analysis of the future financial cash flows generated by selling the electrical energy produced. We apply an indexed semi-Markov model of wind speed that has been shown, in previous investigation, to reproduce accurately the statistical behavior of wind speed. The model is applied to the evaluation of financial indicators like the Internal Rate of Return, semi-Elasticity and relative Convexity that are widely used for the assessment of the profitability of an investment and for the measurement and analysis of interest rate risk. We compare the computation of these indicators for real and synthetic data. Moreover, we propose a new indicator that can be used to compare the degree of utilization of different power plants.

D'Amico, G; Prattico, F

2015-01-01T23:59:59.000Z

496

756 IEEE TRANSACTIONS ON SUSTAINABLE ENERGY, VOL. 4, NO. 3, JULY 2013 Minimization of Wind Farm Operational  

E-Print Network [OSTI]

756 IEEE TRANSACTIONS ON SUSTAINABLE ENERGY, VOL. 4, NO. 3, JULY 2013 Minimization of Wind Farm) of wind turbine at time , denoted as 0 or 1. Energy consumed by an idle wind turbine. Electricity spot, and Guanglin Xu Abstract--Scheduling a wind farm in the presence of uncertain wind speed conditions

Kusiak, Andrew

497

Wind Power Forecasting  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Retrospective Reports 2011 Smart Grid Wind Integration Wind Integration Initiatives Wind Power Forecasting Wind Projects Email List Self Supplied Balancing Reserves Dynamic...

498

Precision electronic speed controller for an alternating-current  

DOE Patents [OSTI]

A high precision controller for an alternating-current multi-phase electrical motor that is subject to a large inertial load. The controller was developed for and is particularly suitable for controlling, in a neutron chopper system, a heavy spinning rotor that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal having a meandering line frequency. The controller includes a shaft revolution sensor which provides a feedback pulse train representative of the actual speed of the motor. An internal digital timing signal generator provides a reference signal which is compared with the feedback signal in a computing unit to provide a motor control signal. In the preferred embodiment, the motor control signal is a weighted linear sum of a speed error voltage, a phase error voltage, and a drift error voltage, each of which is computed anew with each revolution of the motor shaft. The stator windings of the motor are driven by two amplifiers which are provided with input signals having the proper quadrature relationship by an exciter unit consisting of a voltage controlled oscillator, a binary counter, a pair of readonly memories, and a pair of digital-to-analog converters.

Bolie, Victor W. (Albuquerque, NM)

1988-01-01T23:59:59.000Z

499

Control and simulation of a flywheel energy storage for a wind diesel power system  

Science Journals Connector (OSTI)

Abstract Wind diesel power systems (WDPSs) are isolated microgrids which combine wind diesel generators with wind turbine generators. If the WDPS includes a short-term energy storage system (ESS) both the logistic and the dynamic operation are improved. Flywheel based energy storage systems (FESSs) have characteristics that make them very appropriate to be used as short-term ESS in WDPS, so that a FESS, is added to the WDPS. The FESS main components: electrical machine, flywheel, grid converter and electrical machine converter are described. As the main aim of the FESS in the present article is power quality improvement, a robust low cost low-speed FESS (LS-FESS) is selected. The LS-FESS which includes an asynchronous machine (ASM) and a steel flywheel is sized for a particular WDPS. The FESS power converters and ASM can be controlled as if they were a servo but, in order to attain more robustness, it is better to control the ASM converter to maintain a constant DC-voltage in the DC-link and to control the grid converter to exchange the necessary power references with the isolated grid. Finally, in order to verify the proposed low speed FESS, it is simulated along with the WDPS. Simulation results with graphs for the isolated power system frequency and voltage, active powers generated/consumed by the WDPS elements, the FESS-ASM direct and quadrature currents and FESS-flywheel speed are presented for load and wind speed steps. The simulations show a power quality improvement of the isolated microgrid due to the use of the FESS.

R. Sebastián; R. Peńa-Alzola

2015-01-01T23:59:59.000Z

500

Wind turbine  

SciTech Connect (OSTI)

The improvement in a wind turbine comprises providing a tower with a freely liftable mount and adapting a nacelle which is fitted with a propeller windwheel consisting of a plurality of rotor blades and provided therein with means for conversion of wind energy to be shifted onto said mount attached to the tower. In case of a violent wind storm, the nacelle can be lowered down to the ground to protect the rotor blades from breakage due to the force of the wind. Required maintenance and inspection of the nacelle and replacement of rotor blades can be safely carried out on the ground.

Abe, M.

1982-01-19T23:59:59.000Z