The blind recloser of automatic reclosing in a permanent fault brings secondary impact to the distribution network. Thus an active detection scheme for identifying the permanent fault using a phase segregated switch is proposed. In the case of a transient ground fault, the transmission line is equivalent to a capacitance model, and the transient voltage and current are used to obtain the calculated capacitance by the least squares method. The calculated capacitance is similar to the actual value and effectively does not change with time. In the case of a permanent ground fault, the transmission line does not conform to the capacitance model, and the calculated capacitance may be negative and changes drastically with time. In the case of a phase-to-phase fault, one faulty phase is closed, and the existence of the fault point will cause a difference in the transient response of the unclosed phases and there is a large transient line voltage between unclosed phases. For the ground fault, a permanent fault identification criterion is constructed to identify the capacitance parameter using the idea of model identification. For the phase-to-phase fault, a permanent fault identification criterion using transient line voltage is constructed. The PSCAD simulation results show that the proposed method can accurately identify the permanent fault of a distribution network at different fault locations with different transition resistances.

This work is supported by the International Corporation and Communication Program of National Natural Science Foundation of China (No. 52061635105).