Precise Locating Method of Generator Stator Grounding Fault Point Based on Injected Signal

摘要

In view of the difficulty and low accuracy of stator grounding fault location for large generators, a method for accurate stator grounding fault location based on neutral injection signal is presented in this paper. Inject Non-power-frequency current signal into the stator neutral point during shutdown. The branch current is measured at the head and end of the fault phase branch. The fault branch is detected by the current difference comparison method at the head and end of the branch. The coil measurement point in the sub-fault branch is set by the dichotomy method to accurately locate the fault point to the slot number. The principle of adjusting current limiting resistance to improve detection accuracy is analyzed. The method can significantly improve the accuracy of stator grounding fault location. This way can reduce the downtime and effectively increase the efficiency of stator grounding fault treatment.