Design and Implementation of Optimal Control Scheme for DFIG Based Wind Plant to Mitigate Sub-Synchronous Resonance Issues

This article presents an investigation of sub-synchronous resonance (SSR) issues in doubly-fed induction generator (DFIG) based wind plant and proposes an optimal control scheme for its mitigation. The article firstly reviews the causes of SSR, namely compensation level and wind speed in DFIG-based wind plant. The proportional resonance controller with harmonic compensators (PR+HC) is designed to mitigate SSR without compromising total harmonic distortions (THD) in the power signal. The series compensated IEEE first benchmarked model energized with a 100MW DFIG-based wind plant is used as a platform in MATLAB/Simulink for the implementation of the proposed scheme. The comparative analysis of the designed PR+HC controller is carried out with the conventional Proportional Integral (PI) controller to validate the optimal response of PR+HC controller. In addition, high performance of PR+HC in coordination with a flexible AC transmission (FACT) device in terms of damped oscillations and low THD is achieved. The overall simulation results are analyzed in both time domain and frequency domain to authenticate the damped, low harmonic, and smooth response of proposed scheme under varying compensation level and wind speeds.