METHOD AND DEVICE FOR GROUND FAULT PROTECTION OF GENERATOR STATOR WINDING Russian patent published in 1997 - IPC

FIELD: electrical engineering. SUBSTANCE: method involves discrimination and comparison of zero-sequence current difference in starting and finishing leads of stator winding with setting values. In case of single-phase fault, higher harmonic components of mentioned currents difference are discriminated and in case of double faults, intermediate-frequency component is discriminated. Information arrives from differential zero-sequence sensors and zero-sequence voltage sensor. Current signal is received and processed by two responding elements, voltage signal, by starting element. Processed signals passed through logic elements act on final element. EFFECT: enlarged functional capabilities combined with high sensitivity and simple design of protective gear. 6 cl, 4 dwg