Locating sub-cycle faults in distribution network applying half-cycle DFT method

It is necessary to accurately detect and locate sub-cycle faults in order to prevent unexpected outages. However, conventional fault location methods cannot locate these faults as typically data windows longer than the fault´s signature are used for phasor extraction. This paper presents an overall analysis of how the single-phase-ground sub-cycle fault in the distribution network can be located using voltage sag. The half-cycle Discrete Fourier transform is used for phasor extraction in the timedomain simulations. Our results reveal that the proposed approach is capable of accurately locating sub-cycle faults whose duration is between 0.5 and 1.0 cycles. The results also suggest that the placement of meters may significantly affect the capability of the proposed approach to locate sub-cycle faults.