AC Short-Circuit Fault Analysis and Transient Synchronization Stability Study of Wind Farms

Research on synchronous instability caused by AC short-circuit faults in wind farms connected to flexible DC transmission systems primarily focuses on fault-phase synchronization mechanisms and enhancement strategies, often neglecting synchronization issues during the recovery phase after fault clearance. This paper investigates the fault characteristics of wind farms during AC short-circuit events, establishes a transient analysis model, and analyzes the impact of wind turbine converter power factors on stability domains during recovery using the phase plane method. The results indicate that increasing inductive reactive power significantly enhances recovery stability. Simulations demonstrate that maintaining constant apparent power while slightly reducing active power and increasing inductive reactive power stabilizes the system, enabling wind turbines to ride through low-voltage faults and comply with grid integration standards. An optimal power factor is identified to balance low-voltage ride-through capability and power output efficiency.