In this paper, an investigation on oscillation damping enhancement of DFIG with the combined reactive power damping control (RPDC) and virtual inertia control (VIC) is conducted. A brief principle introduction on RPDC and VIC is presented firstly. Then the effect of VIC loop and RPDC loop on the electromechanical oscillation modes of power system is analyzed independently, it is revealed that the RPDC coefficient can play an important role in damping enhancement. The finding is tested using a modified four-machine and two-area system. Further eigenvalue analysis, time-domain simulation and Prony analysis of the case study can verify the theoretical results.

DFIG, Reactive Power Damping Control, Virtual Inertia Control, Electromechanical Oscillation