关键词: 定子接地, 零序电压, 三次谐波, 出口断路器（GCB）

Abstract:

This paper described the principle of generator stator ground protection based on third harmonic, and pointed out that the protection parameters were affected greatly by the primary system parameters, especially the capacitor of GCB. Then the problems of generator stator ground protection based on third harmonic in projects were described and the impact of GCB capacitor on the stator ground protection was analyzed. The results show that the capacitor of GCB will educe the setting values of third harmonic. Finally, this paper presented the matters that should be paid attention during the field measurement and parameter setting of project protection.

Key words: stator ground, zero-sequence voltage, third harmonic, gas circuit breaker（GCB）