Distributed Damping Evaluation for Series-Compensated DFIG-Based Wind Farms During the SSCI

This paper proposes a modal damping loss factor (MDLF) for evaluating the damping distribution of the doubly-fed induction generator (DFIG)-based wind farms during the sub-synchronous control interaction (SSCI). The MDLF can pinpoint the sensitive control parameters of DFIG wind turbine at the oscillatory frequencies by its explicit expression, and quantitively assess the damping contribution induced by each DFIG wind farm in the wind power systems. First, inspired by the concept of damping loss factor in a basic vibration system, we establish the MDLF for evaluating the transient energy dissipation of the SSCI. Then, the MDLF’s explicit expression of an equivalent DFIG wind turbine is derived to evaluate the parameter’s sensitivities. Finally, the application of the MDLF is extend to a DFIG-based wind farm for evaluating the damping distribution. The accuracy and effectiveness of the MDLF is verified by the modal analysis approach and time-domain simulation.