Wind power is increasingly integrated in modern power grids, which brings new challenges to the power system operation. Wind power is fluctuating because of the uncertain nature of wind, whereas wind shear and tower shadow effects also cause periodic fluctuations. These may lead to serious forced oscillation when the frequencies of the periodic fluctuations are close to the natural oscillation frequencies of the connected power system. By using modal analysis and time-domain simulations, this study studies the forced oscillation caused by the wind shear and tower shadow effects. Three forced oscillation mitigation controllers are proposed and compared. A model of direct-drive-full-convertor-based wind farm connected to the IEEE 10-machine 39-bus system is adopted as the test system. The calculations and simulations are conducted in DIgSILENT PowerFactory 14.0. Results are presented to show the effectiveness of the controllers in mitigating the forced oscillation.
Iet Renewable Power Generation, 2013, Vol 7, Issue 6, p. 639-651
Direct-drive-full-convertor-based wind turbine; Wind shear; Tower shadow; Forced oscillation; Small signal stability; Forced oscillation mitigation controller