A System Frequency Response Estimation Method Accounting for Fault-Location-Induced Differences in Frequency Regulation Capability
Short-circuit faults in high-renewable-penetration power systems produce active power deficits and frequency regulation capability losses that vary markedly with fault location, degrading the accuracy of conventional system frequency response (SFR) models. This paper develops a refined SFR correction framework that maps fault location to low-voltage ride-through (LVRT) cluster composition via exact nodal voltage solution, thereby quantifying the initial active power deficit and the frequency regulation capability loss. A permanent magnet synchronous generator (PMSG) multi-state model is established covering steady-state operation, fault ride-through, and frequency regulation. Voltage sag depth and active power recovery rate differences among wind farms are aggregated to compute the system-level total wind power deficit, while a frequency regulation state-switching coefficient is introduced to weight-aggregate an equivalent system frequency regulation capability availability ratio. Validation on the IEEE 10-machine 39-bus system demonstrates that the proposed model reproduces frequency nadir and rate of change of frequency (RoCoF) with errors of 0.016–0.027% and 0.21–0.41%, respectively, against detailed time-domain simulation. Single-fault-scenario computation requires 0.0873 s versus 0.3574 s for the unified structure model and 14.7240 s for detailed time-domain simulation. Batch scanning of 10 fault locations totals 0.892 s, yielding a 173-fold reduction relative to detailed time-domain simulation (154.326 s), enabling offline enumeration and online real-time matching for emergency control strategy deployment.