Fault Detection and Localization for Overhead 11-kV Distribution Lines With Magnetic Measurements

Electric power distribution network holds a critical role in uninterruptable power supply for modern societies. The distribution network comprising of complex of primary and secondary distribution lines is vulnerable to various short-circuit (SC) faults caused by lightning strikes, storms, growing vegetation, animals, insulation breakdown, and other environmental situations. Most SC faults result in breakdowns that need to be repaired in order to restore electric supply to consumers. Rapid and accurate fault localization method helps in an accelerated system restoration process and thus reduces power outage time. In this paper, a new approach related to the noncontact magnetic field (MF)-based measurement system to localize SC faults on 11-kV overhead distribution lines is presented. The method uses highly sensitive and energy-efficient magnetic sensors to detect variations in MF levels measured along the distribution lines. The fault localization algorithm is developed which identifies SC fault on main feeders and its subbranches and then localize the fault by analyzing MF over window size of 20 cycles. The developed algorithm is implemented on a complex distribution system and tested for different cases. Laboratory experiments were conducted to detect and localize SC faults in a multibranch configuration to validate the proposed method, where measurement uncertainty of less than 5% is observed for the worst case scenario.