Fault-Section Location System and Strategy for Single-Phase Ground Faults in Flexible-Grounded Distribution Networks

Leveraging fault indicators to measure phase currents, phase-to-ground voltages, and corresponding waveforms, this paper proposes a fault section location method combined with waveform similarity analysis. A flexible neutral grounding system is developed to address the difficulty of fault detection caused by excessively small zero-sequence currents. By switching the access resistor twice within a specified time interval, a distinct characteristic signal is defined as the trigger signal. The trigger signal enables all fault indicators installed in the distribution network to be activated synchronously and to record the subsequent zero-sequence current and its waveform. Based on the recorded zero-sequence current data, the fault section is located using the db-4 wavelet decomposition method. The proposed method enables rapid and accurate fault location in practical engineering applications, assists maintenance personnel in troubleshooting and repairing faults in a timely manner, and ensures the safe and reliable operation of the distribution system.