In view of the current research situation of the difficulty and low accuracy of stator grounding fault location for large generators, this paper presents a method for accurate location of stator grounding fault based on neutral point injection signal. By injecting non-power frequency current signal into stator neutral point during shutdown, branch current is measured at the first and end of fault phase branch detection of fault branches. By comparison of head and end current differences of branches, the coil measuring point in the branch of sub-fault is set by dichotomous fabric. And the fault point is located to the slot number of stator coil accurately. The implementation process of generator stator grounding fault location and maintenance is proposed. The method can significantly improve the accuracy of stator grounding fault location. And it can reduce the downtime and effectively increase the efficiency of stator grounding fault treatment.

Injection signal,Grounding fault,Current amplitude,Capacitance Current Loss,Locating fault points