Report of an Actual Stator Grounding Fault and Causal Analysis
This paper reports an actual fault with"generator startup and shutdown protection"and"stator grounding pro-tection activation"encountered by an actual hydroplant during trial operation.It describes the procedure performed for lo-cating the fault point,including determining fault phase and narrowing scope of fault cause,and verifies correctness and effectiveness of the calculation formula of grounding resistance and potential used in the procedure.It thereby highlights a method to distinguish between primary equipment grounding and secondary circuit grounding of stator through the afore-mentioned process of treating the fault,so as to provide useful inspiration for plants'operation and maintenance person-nel.