Autonomous Short Circuit Fault Localization System for 11kV Overhead Distribution Lines /

Abstract

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 accelerated system restoration process and thus reduces power outage time. In this paper, a new approach related to non-contact magnetic field (MF) based measurement system to localize SC faults on 11kV 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. Fault localization algorithm is developed which identifies SC fault on main feeders and its sub-branches and then localize the fault by analyzing MF over window size of 20 seconds time period. The proposed algorithm is implemented on distribution system model designed in Simulink (MATLAB) and numerical simulations are conducted for different cases. Scaled laboratory experiments are also performed to validate the proposed method. By comparing the results of simulated and measured approaches, a measurement error of less than 5% is observed.