Design and Implementation of High Impedance Fault Relay Based on Harmonic Analysis Algorithm for Ahvaz 33 kV Distribution Network

Over current relays that are used commonly in distribution system can't detect high impedance fault. Therefore for that purpose it is necessary to design special algorithms. In this paper, a method based on harmonic analysis is presented. In this technique, the proposed relay, after fault occurs, extracts the required harmonic and according designed algorithm, occurrence of fault is reported. Software of this relay for different scenarios of high impedance faults was tested; also its hardware of relay in laboratory tests could correctly identify events.