Method for Suppressing Wind Power Sub-synchronous Resonance Using Dynamic Series Compensator

To address the risk of sub-synchronous resonance (SSR) in doubly-fed induction generator (DFIG)-based wind farms connected to series-compensated transmission systems, this paper proposes an IGBT-based dynamic series compensator (DSC) and its damping control strategy: damping control based on line current (DCLC). DCLC controls the DSC output voltage to maintain the same phase as the line sub-synchronous current, with controllable amplitude. In this configuration, the DSC acts as a positive resistance on the line at sub-synchronous frequencies. By connecting the DSC in series on the grid side, the grid-side resistance is increased, making the system's equivalent resistance positive and thereby achieving SSR suppression. The DSC is connected in series with the fixed series compensator (FSC) to form a hybrid series compensation device (HDSC). Finally, a time-domain simulation model of a typical DFIG wind farm connected to a series-compensated transmission system was built using PSCAD/EMTDC. The effectiveness of DSC in suppressing SSR was verified using both time-domain simulation and frequency scanning methods. Simulation results demonstrate that the DSC can effectively suppress SSR in the system under various wind speed conditions.