Damping of subsynchronous oscillations and improve transient stability for wind farms

This paper investigates the application of STATCOM to stabilize the torsional oscillations of sub-synchronous resonance (SSR) of a wind energy conversion system (WECS). The IEEE system-1 of the second benchmark model for computer simulation of subsynchronous resonance is adopted with integrating aggregated induction generator-based wind turbine to perform the study. A small signal analysis is conducted to study the impact of the series compensation levels and torsional dynamics on system stability. EMTDC/PSCAD is used to simulate the system under study. Due to its simplicity, robustness and ease of implementation, a proportional integral (PI) controller along with auxiliary feedback signals are used to control the inverter firing angle to control the reactive power exchange between the AC system and the STATCOM. The performance of the controller is tested in steady state as well as transient conditions.