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Title: Optimal operation of stationary and mobile batteries in distribution grids

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Publication Date:
Sponsoring Org.:
OSTI Identifier:
Grant/Contract Number:
20699; 20686
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Applied Energy
Additional Journal Information:
Journal Volume: 190; Journal Issue: C; Related Information: CHORUS Timestamp: 2018-01-09 07:58:29; Journal ID: ISSN 0306-2619
Country of Publication:
United Kingdom

Citation Formats

Wang, Yubo, Shi, Wenbo, Wang, Bin, Chu, Chi-Cheng, and Gadh, Rajit. Optimal operation of stationary and mobile batteries in distribution grids. United Kingdom: N. p., 2017. Web. doi:10.1016/j.apenergy.2016.12.139.
Wang, Yubo, Shi, Wenbo, Wang, Bin, Chu, Chi-Cheng, & Gadh, Rajit. Optimal operation of stationary and mobile batteries in distribution grids. United Kingdom. doi:10.1016/j.apenergy.2016.12.139.
Wang, Yubo, Shi, Wenbo, Wang, Bin, Chu, Chi-Cheng, and Gadh, Rajit. Wed . "Optimal operation of stationary and mobile batteries in distribution grids". United Kingdom. doi:10.1016/j.apenergy.2016.12.139.
title = {Optimal operation of stationary and mobile batteries in distribution grids},
author = {Wang, Yubo and Shi, Wenbo and Wang, Bin and Chu, Chi-Cheng and Gadh, Rajit},
abstractNote = {},
doi = {10.1016/j.apenergy.2016.12.139},
journal = {Applied Energy},
number = C,
volume = 190,
place = {United Kingdom},
year = {Wed Mar 01 00:00:00 EST 2017},
month = {Wed Mar 01 00:00:00 EST 2017}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.apenergy.2016.12.139

Citation Metrics:
Cited by: 9works
Citation information provided by
Web of Science

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  • The objective of the analysis presented is to outline and validate a methodology for the optimization of MV distribution network operation. Loss minimization, taking into account the protective scheme applied, reliability and voltage quality aspects, are attained. Loss minimization is achieved by the installation of shunt capacitors and reconfiguration of the network. Two different reconfiguration methods are applied and compared. Special attention is given to the impact of network reconfiguration on the protective scheme applied, as well as on network voltage quality and reliability. Loads are assumed to be time variable, following typical daily curves. A general optimization method, suitablemore » for overhead and underground networks, is outlined and validated through applications.« less
  • Purpose: X-ray scatter is a major detriment to image quality in cone-beam CT (CBCT). Existing geometries exhibit strong differences in scatter susceptibility with more compact geometries, e.g., dental or musculoskeletal, benefiting from antiscatter grids, whereas in more extended geometries, e.g., IGRT, grid use carries tradeoffs in image quality per unit dose. This work assesses the tradeoffs in dose and image quality for grids applied in the context of low-dose CBCT on a mobile C-arm for image-guided surgery. Methods: Studies were performed on a mobile C-arm equipped with a flat-panel detector for high-quality CBCT. Antiscatter grids of grid ratio (GR) 6:1-12:1,more » 40 lp/cm, were tested in ''body'' surgery, i.e., spine, using protocols for bone and soft-tissue visibility in the thoracic and abdominal spine. Studies focused on grid orientation, CT number accuracy, image noise, and contrast-to-noise ratio (CNR) in quantitative phantoms at constant dose. Results: There was no effect of grid orientation on possible gridline artifacts, given accurate angle-dependent gain calibration. Incorrect calibration was found to result in gridline shadows in the projection data that imparted high-frequency artifacts in 3D reconstructions. Increasing GR reduced errors in CT number from 31%, thorax, and 37%, abdomen, for gridless operation to 2% and 10%, respectively, with a 12:1 grid, while image noise increased by up to 70%. The CNR of high-contrast objects was largely unaffected by grids, but low-contrast soft-tissues suffered reduction in CNR, 2%-65%, across the investigated GR at constant dose. Conclusions: While grids improved CT number accuracy, soft-tissue CNR was reduced due to attenuation of primary radiation. CNR could be restored by increasing dose by factors of {approx}1.6-2.5 depending on GR, e.g., increase from 4.6 mGy for the thorax and 12.5 mGy for the abdomen without antiscatter grids to approximately 12 mGy and 30 mGy, respectively, with a high-GR grid. However, increasing the dose poses a significant impediment to repeat intraoperative CBCT and can cause the cumulative intraoperative dose to exceed that of a single diagnostic CT scan. This places the mobile C-arm in the category of extended CBCT geometries with sufficient air gap for which the tradeoffs between CNR and dose typically do not favor incorporation of an antiscatter grid.« less
  • Mammography without a grid and with both a stationary and a moving grid was performed on 46 women. Mean gland dose to the breast was increased two to four times using either grid. Grid lines were apparent on films obtained with a stationary grid, but were not seen on those obtained with a moving grid. Although the radiation dose is the same with both grids, differences in the design of the two devices may lead to a personal preference in deciding which grid to use.
  • Purpose: Grid artifacts are caused when using the antiscatter grid in obtaining digital x-ray images. In this paper, research on grid artifact reduction techniques is conducted especially for the direct detectors, which are based on amorphous selenium. Methods: In order to analyze and reduce the grid artifacts, the authors consider a multiplicative grid image model and propose a homomorphic filtering technique. For minimal damage due to filters, which are used to suppress the grid artifacts, rotated grids with respect to the sampling direction are employed, and min-max optimization problems for searching optimal grid frequencies and angles for given sampling frequenciesmore » are established. The authors then propose algorithms for the grid artifact reduction based on the band-stop filters as well as low-pass filters. Results: The proposed algorithms are experimentally tested for digital x-ray images, which are obtained from direct detectors with the rotated grids, and are compared with other algorithms. It is shown that the proposed algorithms can successfully reduce the grid artifacts for direct detectors. Conclusions: By employing the homomorphic filtering technique, the authors can considerably suppress the strong grid artifacts with relatively narrow-bandwidth filters compared to the normal filtering case. Using rotated grids also significantly reduces the ringing artifact. Furthermore, for specific grid frequencies and angles, the authors can use simple homomorphic low-pass filters in the spatial domain, and thus alleviate the grid artifacts with very low implementation complexity.« less
  • Here, recent experiments in DIII-D have led to the discovery of a means of modifying edge turbulence to achieve stationary, high confinement operation without Edge Localized Mode (ELM) instabilities and with no net external torque input. Eliminating the ELM-induced heat bursts and controlling plasma stability at low rotation represent two of the great challenges for fusion energy. By exploiting edge turbulence in a novel manner, we achieved excellent tokamak performance, well above the H 98y2 international tokamak energy confinement scaling (H 98y2=1.25), thus meeting an additional confinement challenge that is usually difficult at low torque. The new regime is triggeredmore » in double null plasmas by ramping the injected torque to zero and then maintaining it there. This lowers ExB rotation shear in the plasma edge, allowing low-k, broadband, electromagnetic turbulence to increase. In the H-mode edge, a narrow transport barrier usually grows until MHD instability (a peeling ballooning mode) leads to the ELM heat burst. However, the increased turbulence reduces the pressure gradient, allowing the development of a broader and thus higher transport barrier. A 60% increase in pedestal pressure and 40% increase in energy confinement result. An increase in the ExB shearing rate inside of the edge pedestal is a key factor in the confinement increase. Strong double-null plasma shaping raises the threshold for the ELM instability, allowing the plasma to reach a transport-limited state near but below the explosive ELM stability boundary. The resulting plasmas have burning-plasma-relevant ╬▓ N=1.6-1.8 and run without the need for extra torque from 3D magnetic fields. To date, stationary conditions have been produced for 2 s or 12 energy confinement times, limited only by external hardware constraints. Stationary operation with improved pedestal conditions is highly significant for future burning plasma devices, since operation without ELMs at low rotation and good confinement is key for fusion energy production.« less