An Online Faulty Sub‐Feeder Identification Method for the NUGS Single‐Phase Earth Fault Based on the Faulty Phase Current Feature Recognition

Abstract

Single-phase earthing is a type of fault that occurs frequently in a distribution network. To improve the reliability of the power supply, neutral un-effectively grounded system (NUGS) is adopted in many countries. However, it will lead to the difficulty of identification of the faulted components. Existing faulty sub-feeder identification methods place severe limit on field feasibility in various aspects when dealing with this problem. In this paper, an online single-phase earth faulty sub-feeder identification method based on the faulty phase current feature recognition is introduced and assessed according to the universal distribution characteristics of the high-frequency transient components. In comparison with existing location methods, the proposed method is independent of zero-sequence current measurement and has the natural faulty feeder selection capability. Besides, it can be implemented economically by virtue of the existing distribution automation system in the NUGS. The effectiveness of the proposed method under various fault conditions is verified by Power Systems Computer Aided Design/Electromagnetic Transients including DC (PSCAD/EMTDC) simulation and comparison studies.