Coordinated control of wind energy conversion systems for mitigating subsynchronous interaction in DFIG-based wind farms

The paper presents methods for mitigating subsynchronous interaction (SSI) between doubly fed induction generator (DFIG) based wind farms and series capacitor compensated transmission systems. SSI damping is achieved by introducing a supplemental control signal in the reactive power control loop of the grid side converter of DFIG and full-scale frequency converter wind turbines, as well as in the reactive power control loop of the HVDC onshore multimodule converter (MMC) of offshore wind farms. This paper also investigates the impact of the phase imbalance series capacitive compensation concept that was introduced in the 1990s as a subsynchronous resonance countermeasure on SSI damping. The validity and effectiveness of the proposed methods are demonstrated on a test benchmark through time domain simulation studies using the ElectroMagnetic Transient Program (EMTP-RV).