Experimental Study on the Characteristics and Impact of Single-phase High-impedance Grounding Faults Considering Feeder Imbalance

For analyze the impact of feeder imbalance on the transient characteristics of single-1 phase high-impedance grounding faults, an equivalent circuit for single-phase grounding faults is 2 established, which includes multiple feeder imbalance voltage sources. The magnitude and phase of 3 an unbalanced voltage source in a single feeder are solely related to the inherent ground imbalance of 4 that feeder. Meanwhile, the significance of transient fault current characteristics depends on the size 5 of the transition resistance. We propose a state-space-based fault transition resistance identification 6 method and employ linear regression to determine the single-phase ground fault resistance. From 7 the moment the fault occurs, the resistance will gradually decrease from a larger value. The initial 8 resistance, which has a significant effect on the fault transient characteristics, is often large, potentially 9 causing no notable difference between the amplitude of the feeder transient current and the inherent 10 current after the fault. The inherent imbalance of the feeder can severely impact the accuracy of using 11 transient characteristics for line selection.