Study on the Oscillation Center of DFIG-based Wind Farm Power System

Due to the characteristics of randomness, volatility and low inertia, the large-scale integration of new energy units has changed the original power flow distribution and deteriorated the transient stability of the system, resulting in the migration of the system oscillation center, which can even affect the accurate action of the splitting control. Aiming at the problem that the integration of doubly-fed induction generator (DFIG) affects the migration law of the oscillation center, firstly the Thevenin equivalent model of DFIG is constructed and the operating characteristics are analyzed. And then the equivalent admittance model of DFIG is constructed. Finally, based on the equivalent admittance model, the migration law of the oscillation center in the DFIG-based wind power system is analyzed. The results show that the out-of-step center (OOSC) moves away from the DFIG-based wind farm integration point when DFIG generates reactive power and moves close to the integration point when DFIG absorbs reactive power. While the migration range of the oscillation center extends to the entire line.