Mitigation of IGE using STATCOM with DFIGs

Abstract

This paper presents application of STATCOM for damping of low frequency oscillations produced due to induction generation effect (IGE) type sub-synchronous resonance (SSR) in doubly-fed induction generator (DFIG)-based wind farms. In this study DFIG-based wind farm is connected to infinite bus through series-compensated transmission line. Transmission line parameters are derived from IEEE first benchmark model for digital simulations of SSR. To analyze the risk of SSR, time-domain simulations are performed for different cases of series compensation level of transmission line. Through results of performed simulations, low frequency oscillations are observed in torque, voltage and current waveforms of DFIG and bus at generator node. Studied system is found potentially unstable due to risk of SSR, with higher compensation level. Thus, paper incorporates application of STATCOM with DC capacitors’ size calculation and it’s control system to mitigate SSR. After calculation of DC capacitor size, simulations are again performed and oscillations produced due to SSR are found stable. Mitigation of IGE using STATCOM in DFIGs is verified through simulation results on MATLAB/Simulink.