Judgement on arc grounding fault of digitalized distribution network

Based on the fact that the arc-induced voltage is very harmful to equipment,especially those intelligent ones of digitalized distribution network,the performance of existing arc suppression devices cannot be satisfied in equipment and operation principle,with an example of unearthed 35 kV grid,a concept of critical zero-sequence voltage was proposed which can distinguish intermittent arcing earthing fault and self-extinguishing fault.Using this capability together with the dynamic characteristics of fault current,a criteria for intermittent arcing earthing fault in distribution network was presented.Based on the criteria,the preventing strategy for arc-induced voltage of digitalized distribution network was presented.The results show that the proposed criterion is a key factor to prevent the arc-induced voltage of digitalized distribution network.The criterion is correct,reliable and suitable for both circumstances of low or high transition resistance.