Harmonic Analysis of High-Impedance Fault Experimental Current Waveforms Using Fast Fourier Transform

High impedance faults (HIFs) detection in overhead distribution networks have been a major challenge for utility engineers long time. The current flowing to ground path is so low that conventional protection does not detect HIFs. problem becomes more critical when HIFs occur rural feeders with many single-wire earth return networks, since the neutral usually set above normal unbalance of circuit avoid its undue actuation, limiting sensitivity this single phase-to-ground faults. Methods based on harmonic content analysis HIF stand out their simplicity, practicality, and ease implementation. However, such methods do present reliability issues, indices thresholds need be well adjusted, reconciling dependability security function. This paper presents study components waveforms, obtained through experimental tests 13,8 kV network, using Fast Fourier Transform. analyzed waveforms recorded SEL-751 relay 74 FAI events.