Phase current fault component based single-phase earth fault segment location in non-solidly earthed distribution networks

A single-phase earth fault section location method based on fault component phase current in non-solidly earthed distribution networks is proposed. During a single-phase earth fault, the fault component currents of three phases obtained from the healthy lines and the sections at the back of the fault point are of the same amplitude and waveform, whereas those differ a lot in the sections between the fault point and the bus. On the basis of this characteristic, a fault section location method is put forward: earth fault detection devices are installed at every section, and each one measures and compares its three phase fault component currents independently, thus the sections between the fault point and the bus are identified, and the fault section location is achieved combining with the network topology. The detailed flow chart and criteria are also given. Simulation results prove the validity and reliability of the method proposed. This novel method requires only current signals, involves a simple principle and a bootstrap characteristic, and is expected in practical application in distribution networks.