To address the problem of insufficient operating speed caused by step-by-step setting coordination in traditional definite-time overcurrent protection for load-switch-based medium-voltage ring networks in urban regional railways, this paper proposes a fast protection method based on differential current. The fault section is identified using the fault characteristics of differential current, and the fault information is transmitted to the master station via the GOOSE network. The master station then controls the tripping of the outgoing circuit breaker at the substation to achieve rapid fault clearance. At the same time, the outgoing current of the substation is monitored. When the outgoing current drops below the preset threshold, a command is sent via the GOOSE network to control the tripping of the load switches on both sides of the fault section, completing the fault isolation. After fault isolation, the circuit breaker at the substation outgoing line and normally open point are closed to restore power supply to the healthy area. Simulation results show that under different fault types, locations, and transition resistances, the proposed method can achieve rapid protection operation and effective fault isolation, significantly improving protection speed and providing a reliable guarantee for the safe and stable operation of the load-switch-based medium-voltage ring network in urban regional railway systems based on load switches.

urban regional railway  /  medium-voltage ring network  /  load switch  /  protection method  /  fault isolation