Impact of PMSG on SSR of DFIGs connected to series‐compensated lines based on the impedance characteristics

Abstract

Doubly-fed induction generators (DFIGs) connected to series-compensated transmission system is facing the risk of sub-synchronous resonance (SSR). In recent years, SSR events have occurred many times in the area with large-scale wind power plants in Guyuan, Zhangjiakou. Previous studies have shown that DFIGs exhibit negative damping at sub-synchronous frequencies, thus leading to the SSR phenomenon. The permanent magnet synchronous generator (PMSG) is decoupled from the grid by a full-power converter, so it does not participate in the SSR process. In this study, the impact of PMSG on SSR will be analysed based on the impedance characteristics. The results show that PMSG enhances system damping in some frequency bands and deteriorates the system damping in other frequency bands.