Large-scale wind farm has become an important factor affecting the transient stability of power system. In view of the lack of theoretical research on the transient power angle stability of multi-machine system connected with wind farm, this paper proposes a method to analyze the transient power angle stability of multi-machine system with doubly-fed induction generator (DFIG) based wind farm. By modifying and contracting the bus voltage matrix, thus the influence of wind farm on the mutual synchronization between synchronous generators is quantified to the variation of electrical distance between synchronous generators. Furtherly, according to the extended equal area criteria, the relation between the equivalent mechanical power of the system and wind farm’s power output or access position is derived, and finally the influence regularity of wind farm access location on transient stability of practical multi-machine power system is revealed, which provides a theoretical guidance for the scientific configuration of wind farm considering the LVRT scheme and access location synthetically. In simulation, the variation of electrical distances between synchronous generator nodes caused by different DFIG location is analyzed, and the power angle variation in the cases of two LVRT schemes of DFIG at different grid connection point are simulated and compared to verify the validity of proposed method.
Keywords wind farm, transient stability, multi-machine system, bus admittance matrix, low voltage ride through