Faulty Feeder Detection Method for Pole-to- ground Fault in Radial Flexible DC Distribution Networks

After a pole-to-ground fault occurs in flexible DC distribution networks adopting small current grounding mode, the fault pole voltage drops and the non-fault pole voltage rises, which threatens the equipment insulation and system safety. Therefore, it is of great significance to study the fast and accurate faulty feeder detection technology. Based on the analysis of frequency band characteristics of distributed capacitive current after pole-to-ground fault in radial flexible DC distribution networks, a faulty feeder detection method based on multi-band characteristics of transient zero-mode current is proposed. In this paper, the zero-mode voltage change rate is utilized as detection activation criterion. Then, the fuzzy entropy value of each band of transient zero-mode current is calculated to construct the characteristic matrix. Finally, the fuzzy C-means clustering is performed on the characteristic matrix to detect the faulty feeder. Simulation results verify the higher adaptability, reliability, and accuracy of the designed method.