Proposition of an interharmonic-based methodology for high-impedance fault detection in distribution systems

This study presents the preliminary results of a new methodology for detecting high-impedance faults in distribution systems based on interharmonic signatures. The methodology involves incorporation of an interharmonic current analysis system into a conventional protection system, such as automatic reclosers and sectionalisers. To check the functionality of the proposed methodology, the authors carried out field tests on different types of soil, involving instantaneous current waveform measurements during the occurrence of faults. The results suggest that the methodology, based on interharmonic currents produced by variations in electric arc length during the occurrence of high-impedance faults, shows great promise when it comes to detection of the disturbance.