Impact Analysis of Wind Turbine Participation in Frequency Regulation on First-Swing Rotor Angle Stability of Interconnected Power Systems Considering System Topology Influence Factor

Introduction: With the large-scale integration of wind farms into power systems, the implementation of frequency regulation control strategies has become essential. At the same time, their influence on transient rotor angle stability is becoming increasingly significant. This study examines the effect of wind farm frequency regulation on transient stability during a three-phase fault on the tie line of a regional interconnected power system. Method: First, a mathematical model of the wind-integrated interconnected system is established to derive the functional relationship between the wind power droop coefficient and the equivalent electromagnetic power. By defining a System Topology Influence Factor (FST), the impact of wind power frequency regulation on transient energy is theoretically analyzed. Second, to address the issue of power distribution coefficient resetting caused by topology changes during faults, the differential mechanism of FST in acceleration and deceleration stages is revealed. This clarifies the effects of additional droop control on first-swing stability under different wind turbine grid-connection scenarios. Result: When wind turbines integrate into the sending-end generator group, droop control significantly reduces transient energy and improves first-swing rotor angle stability, with efficacy positively correlated to the droop coefficient. Conversely, connection to the receiving-end group leads to the opposite outcome. Discussion: The agreement between simulation and theoretical analysis supports the application of FST in transient stability assessment, underscoring the significant impact of system topology on stability analysis. Conclusion: This study validates FST as a valuable tool for transient stability analysis and offers new insights for optimizing control strategies in wind-integrated interconnected systems.