DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Design and analysis of a wake steering controller with wind direction variability

Journal Article · · Wind Energy Science (Online)

Wind farm control strategies are being developed to mitigate wake losses in wind farms, increasing energy production. Wake steering is a type of wind farm control in which a wind turbine's yaw position is misaligned from the wind direction, causing its wake to deflect away from downstream turbines. Current modeling tools used to optimize and estimate energy gains from wake steering are designed to represent wakes for fixed wind directions. However, wake steering controllers must operate in dynamic wind conditions and a turbine's yaw position cannot perfectly track changing wind directions. Research has been conducted on robust wake steering control optimized for variable wind directions. In this paper, the design and analysis of a wake steering controller with wind direction variability is presented for a two-turbine array using the FLOw Redirection and Induction in Steady State (FLORIS) control-oriented wake model. First, the authors propose a method for modeling the turbulent and low-frequency components of the wind direction, where the slowly varying wind direction serves as the relevant input to the wake model. Next, we explain a procedure for finding optimal yaw offsets for dynamic wind conditions considering both wind direction and yaw position uncertainty. We then performed simulations with the optimal yaw offsets applied using a realistic yaw offset controller in conjunction with a baseline yaw controller, showing good agreement with the predicted energy gain using the probabilistic model. Using the Gaussian wake model in FLORIS as an example, we compared the performance of yaw offset controllers optimized for static and dynamic wind conditions for different turbine spacings and turbulence intensity values, assuming uniformly distributed wind directions. For a spacing of five rotor diameters and a turbulence intensity of 10 %, robust yaw offsets optimized for variable wind directions yielded an energy gain equivalent to 3.24 % of wake losses recovered, compared to 1.42 % of wake losses recovered with yaw offsets optimized for static wind directions. In general, accounting for wind direction variability in the yaw offset optimization process was found to improve energy production more as the separation distance increased, whereas the relative improvement remained roughly the same for the range of turbulence intensity values considered.

Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Wind Energy Technologies Office
Grant/Contract Number:
AC36-08GO28308
OSTI ID:
1677495
Report Number(s):
NREL/JA--5000-78105; MainId:32014; UUID:37a60eed-8a12-4a9f-8c58-6592d6e5d180; MainAdminID:18704
Journal Information:
Wind Energy Science (Online), Journal Name: Wind Energy Science (Online) Journal Issue: 2 Vol. 5; ISSN 2366-7451
Publisher:
European Wind Energy Association - CopernicusCopyright Statement
Country of Publication:
United States
Language:
English

References (31)

Optimization Under Uncertainty for Wake Steering Strategies journal May 2017
Experimental and theoretical study of wind turbine wakes in yawed conditions journal October 2016
Active wake control: An approach to optimize the lifetime operation of wind farms: Active wake control: An approach to optimize the lifetime operation of wind farms journal February 2018
Initial results from a field campaign of wake steering applied at a commercial wind farm – Part 1 journal January 2019
Evaluation of the wind direction uncertainty and its impact on wake modeling at the Horns Rev offshore wind farm: Wind direction uncertainty and its impact on wake modeling journal May 2013
Analysis of control-oriented wake modeling tools using lidar field results journal January 2018
Simulation of Stochastic Processes by Spectral Representation journal April 1991
Wake steering via yaw control in multi-turbine wind farms: Recommendations based on large-eddy simulation journal June 2019
Robust active wake control in consideration of wind direction variability and uncertainty journal January 2018
Wind direction estimation using SCADA data with consensus-based optimization journal January 2019
Estimating the wake deflection downstream of a wind turbine in different atmospheric stabilities: an LES study journal January 2016
Assessment of wind turbine component loads under yaw-offset conditions journal January 2018
Field test of wake steering at an offshore wind farm journal January 2017
Evaluating techniques for redirecting turbine wakes using SOWFA journal October 2014
Experimental and theoretical study of wind turbine wakes in yawed conditions dataset January 2020
Validation of a lookup-table approach to modeling turbine fatigue loads in wind farms under active wake control journal January 2019
Turbine Inflow Characterization at the National Wind Technology Center journal May 2013
Wind farm control: Addressing the aerodynamic interaction among wind turbines conference June 2009
A Large-Eddy Simulations of Wind-Plant Aerodynamics
  • Churchfield, Matthew; Lee, Sang; Moriarty, Patrick
  • 50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition https://doi.org/10.2514/6.2012-537
conference November 2012
Crop Wind Energy Experiment (CWEX): Observations of Surface-Layer, Boundary Layer, and Mesoscale Interactions with a Wind Farm journal May 2013
Combining induction control and wake steering for wind farm energy and fatigue loads optimisation journal June 2018
Wind plant power optimization through yaw control using a parametric model for wake effects-a CFD simulation study: Wind plant optimization by yaw control using a parametric wake model journal December 2014
A tutorial on control-oriented modeling and control of wind farms conference May 2017
Simulation comparison of wake mitigation control strategies for a two-turbine case: Simulation comparison of wake mitigation control strategies for a two-turbine case journal October 2014
Definition of a 5-MW Reference Wind Turbine for Offshore System Development report February 2009
The aerodynamics of the curled wake: a simplified model in view of flow control journal January 2019
Analytical Modeling of Wind Farms: A New Approach for Power Prediction journal September 2016
A new analytical model for wind-turbine wakes journal October 2014
Wind tunnel testing of wake control strategies conference July 2016
A simulation study demonstrating the importance of large-scale trailing vortices in wake steering journal January 2018
Wind tunnel tests on controllable model wind turbines in yaw conference January 2016

Cited By (1)

Wake steering optimization under uncertainty journal January 2020