Subsynchronous control interaction (SSCI) in DFIG-based wind farms has attracted intensive attention from the academia. In order to further study the mechanism of SSCI, this paper carries out equivalent circuit modeling. Firstly, based on the numerical equivalent circuit of PI control unit, the equivalent model of RSC is built. Furthermore, the RSC model is simplified by PI parameter sensitivity analysis, and the impedance-frequency curve of the target system is obtained by frequency scanning. Then, the mechanism and influencing factors of SSCI are studied based on the equivalent circuit model, which are verified by simulation analysis finally.

DFIG-based wind farms, SSCI, SSO, frequency scanning,Equivalent Circuit Modeling