Safe Sub Synchronous Oscillations Response for Large DFIG-Based Wind Farms

This paper presented an accurate analysis of the instability in DFIG-based wind farms due to the use of series compensation and provided maximum power extraction from these farms using the high compensation without the unstable sub-synchronous oscillation occurrence. For this purpose, using modal analysis, it is first shown that the main cause of this instability is low wind speed in the high compensation. This issue causes the series compensated DFIG-based wind farms is unstable due to a sub-synchronous mode. In order to prevent the unstable sub-synchronous oscillation occurrence, a supplementary controller called SSRIPC and DFIG controllers are used. Also, for good dynamic response and proper use of the SSRIPC, an objective function considered based on three factors of minimum damping ratio, overshoot, and settling time of the oscillations. By accurate optimization of the proposed controller using root-locus and PSO algorithm, it is prevented the instability caused by sub-synchronous resonance and sub-synchronous control interaction that are classes of the sub-synchronous oscillations. IEEE SSR first benchmark model and MATLAB/Simulink software are used to validate the performance of the proposed method.