Research on the open phase protection for three-phase five-column arc suppression coil

The paper introduced a three-phase five-column arc suppression coil (TPFCASC) and discussed its autotracking compensation theory, namely, extremum method. Then the authors briefly analyzed the single phase to ground fault of a neutral point grounded by arc suppression coil (ASC) system. Using symmetrical-component method and complex sequence network, the paper detailedly deduced the voltage variation of the distribution network when happening the open phase at the TPFCASC. The author draw a conclusion that in both single and double open phase fault the zero-sequence voltage of the network would appear. The magnitude of the zero-sequence voltage had relation to the out-of-resonance degree of the ASC and the damping rate of the distribution network. Last, the paper designed the protection scheme for the open phase fault at the TPFCASC by using both the zero-sequence voltage of the network and the phase current of the TPFCASC.