AN IMPROVED METHOD FOR HIGH IMPEDANCE FAULT DETECTION IN MEDIUM VOLTAGE NETWORKS

This paper presents a set of rules for an intelligent algorithm of high impedance fault detection by observing the phase to ground voltage, phase to phase current and harmonics of fault current. Several techniques to detect high impedance faults already exist for example current injection in the neutral, superposing voltage signals, harmonic analysis, neural networks. The main disadvantage of all methods is that the normal system activity may cause false tripping of the protection device. Our goal is to give a set of rules for an algorithm that can make a secure decision that a particular feeder event is high impedance fault. The set of rules was carried out from simulation results simulated in MATLAB. The proposed approach was trained and tested with 200 data sets and provides excellent results.