There is no feasible method to discriminate between permanent fault and transient fault after the three-phase circuit breakers are tripped. The reclosing onto a permanent fault may cause an impact on the system. So a phase-by-phase adaptive reclosing sequence for single-phase earth fault is proposed in this paper. When a fault occurs on the transmission line or reclosing onto a permanent fault, the fault line three-phase circuit breakers are tripped. Then the circuit breaker of the non-fault-phase is closed on one side. Permanent fault is discriminating from transient fault by voltage of fault phase. To permanent fault, the circuit breaker will be tripped again. As for transient fault, the circuit breakers of the rest phases are closed. The PSCAD/EMTDC simulation results verify its correctness and effectiveness.

adaptive reclosure,phase by phase reclosure,reclosing sequence,permanent fault,reclosing overvoltage