Judgement of the grounding fault and fault line selection for resonant network with adjustable arc suppression coil

For analysis the characteristic of the network with the arc suppression coil (ASC), zero-sequence models of the ASC network for both the fault state and the normal state are developed and m parameter of the line is defined. The novel method for the grounding fault judgment is present, in which the voltage of the neutral point and ratios of m parameters of two lines are used at the same time. The proposed method is more reliable than the traditional method. The value of m parameter of the fault line is the maximal during the grounding existing, including the grounding directly and grounding through resistor, the characteristic of which is effective to select the fault line. The proposed method for the fault line selection is valid to the fault grounding both directly and through resistor. Simulation results show that proposed methods in this paper are correct. The results from the measured waveforms also show that the method for the fault line selection is correct.