In distribution networks with distributed generation

if circuit breakers blindly reclose onto permanent faults

the resulting transient stress can cause severe impacts on the distribution network and lead to secondary voltage dips in distributed generation units

thereby increasing the probability of disconnection and affecting overall system stability. To address this problem

a permanent fault identification method suitable for active distribution networks is proposed based on phase segregated switch technology. First

considering the low-voltage ride-through capability and current-limiting characteristics of distributed generation

an equivalent analytical model of distributed generation is established

and their influence on auto-reclosing operations in distribution networks is investigated. Second

voltage characteristics under different fault types during single-phase reclosing are analyzed

and a fault type identification criterion based on the voltage recovery ratio is proposed. Finally

simulation results show that the proposed fault type identification method can accurately distinguish transient faults and permanent faults under different fault types. The method is not affected by the capacity of distributed generation and fault location

and has strong tolerance to transition resistance.