Vali, Mehdi and Petrović, Vlaho and Steinfeld, Gerald and Y. Pao, Lucy and Kühn, Martin (2019) An active power control approach for wake-induced load alleviation in a fully developed wind farm boundary layer. Wind Energy Science, 4 (1). pp. 139-161. ISSN 2366-7451

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Abstract

This paper studies a closed-loop wind farm control framework for active power control (APC) with a simultaneous reduction of wake-induced structural loads within a fully developed wind farm flow interacting with the atmospheric boundary layer. The main focus is on a classical feedback control, which features a simple control architecture and a practical measurement system that are realizable for real-time control of large wind farms. We demonstrate that the wake-induced structural loading of the downstream turbines can be alleviated, while the wind farm power production follows a reference signal. A closed-loop APC is designed first to improve the power-tracking performance against wake-induced power losses of the downwind turbines. Then, the nonunique solution of APC for the wind farm is exploited for aggregated structural load alleviation. The axial induction factors of the individual wind turbines are considered control inputs to limit the power production of the wind farm or to switch to greedy control when the demand exceeds the power available in the wind. Furthermore, the APC solution domain is enlarged by an adjustment of the power set-points according to the locally available power at the waked wind turbines. Therefore, the controllability of the wind turbines is improved for rejecting the intensified load fluctuations inside the wake. A large-eddy simulation model is employed for resolving the turbulent flow, the wake structures, and its interaction with the atmospheric boundary layer. The applicability and key features of the controller are discussed with a wind farm example consisting of 3×4 turbines with different wake interactions for each row. The performance of the proposed APC is evaluated using the accuracy of the wind farm power tracking and the wake-induced damage equivalent fatigue loads of the towers of the individual wind turbines.

Item Type:	Article
Additional Information:	Publiziert mit Hilfe des DFG-geförderten Open Access-Publikationsfonds der Carl von Ossietzky Universität Oldenburg.
Subjects:	Science and mathematics > Physics
Divisions:	Faculty of Mathematics and Science > Institute of Physics (IfP) Scientific Centers > ForWind Center for Wind Energy Research
Date Deposited:	19 Mar 2020 08:20
Last Modified:	19 Mar 2020 08:20
URI:	https://oops.uni-oldenburg.de/id/eprint/4500
URN:	urn:nbn:de:gbv:715-oops-45819
DOI:	10.5194/wes-4-139-2019
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