Aiming at the problem that the zero-sequence protection cannot act when intermittent arcing ground fault occurs in the flexible grounding system of distribution network neutral point via arcing coil and resistance,an identification method based on the zero-sequence current,and the cumulative duration of fault is proposed.Firstly,the amplitude characteristics of the zero-sequence current of the faulted line and the zero sequence current of the non-faulted line are analyzed when the ground fault occurs in the flexible grounding system.Secondly,the fault identification criteria are proposed by utilizing the difference in effective values between different lines and combining with the cumulative fault duration.Finally,different arc models are established by electromagnetic transient analysis program.Simulation and calculation results verify the effectiveness of the method.The method can realize the identification of intermittent arcing ground faults in flexible grounding systems.
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