Single line-to-ground fault current analysis for resonant grounded power distribution networks in bushfire prone areas

In bushfire-prone regions, powerline faults, notably single line-to-ground (SLG) faults, are significant contributors to wildfires. In order to promptly mitigate conflagration risks and reduce fault currents from SLG faults, the resonant grounded (RG) technique is implemented. Nevertheless, the literature has not reported a comprehensive derivation of SLG faults using this grounding method. The dynamic phasors method is used in this study to extract fault current characteristics, which are subject to substantial variations under various operating conditions, including harmonics, fault impedance variations, and the compensation levels necessary for resonance. The behavior of fault currents resulting from SLG faults is analyzed in this work by first deriving the fault current under RG conditions, accounting for leakage parameters, and subsequently incorporating harmonic components. The simulation results unequivocally demonstrate that the fault current retains a residual component, even under ideal resonance conditions, and that the ground fault neutralizer does not suppress this residual fault current. The analysis presented indicates that it is imperative to exercise caution when selecting the resonant grounding approach. Further, this method can be employed to extract the remaining fault current component, which is not explicitly accounted for, in order to identify faulty feeders in nonlinear high impedance fault scenarios.