Interharmonics based high impedance fault detection in distribution systems using maximum overlap wavelet packet transform and a modified empirical mode decomposition

Despite extensive research, high impedance fault (HIF) detection remains challenging because it is always associated with low magnitude, nonlinear, asymmetric and random fault currents. This paper presents a new technique for arcing high impedance ground fault detection in distribution feeders through analysis of inter harmonic content of the current signal. The origin of interharmonics is related to the random variation of the electric arc associated with HIF. For effective separation of interharmonic components, a novel method using maximum overlap discrete wavelet packet transform (MODWPT) and a newly developed special knot based empirical mode decomposition (EMD) is presented. The results indicate that the proposed scheme can reliably detect HIFs with a reasonable detection speed and at the same time achieve high security against no-fault cases.