Identification of Permanent Faults for Three-phase Adaptive Reclosure of the Transmission Lines With Shunt Reactors

This paper proposes a new method to distinguish transient faults and permanent faults for transmission lines with shunt reactors, which uses the inductance parameter identification results of shunt reactors to realize three-phase adaptive reclosure (TPAR). For a transient phase-to-phase fault, the primary charging by the shunt reactors and the capacitances in the tripped phases is released respectively by the self-oscillating loop after the arc is fully extinguished. However, as for a permanent phase-to-phase fault, due to the existence of the fault point, the stored energy in the fault phases is released by the fault loop, but the charged energy in the non-fault-phase is weaken by its self-oscillating loop. Therefore, a current-based TPAR scheme is proposed to identify permanent faults from phase-to-phase faults, which uses the calculated inductances of the shunt reactors by the transient π-type model and employs the difference between the calculated inductances and the real ones to detect transient and permanent faults. Theoretically, in the case of transient faults, the calculated inductances of the shunt reactors are approximately same with real ones, but for permanent faults, the calculated inductances are different significantly from the real ones. ATP simulation results show that the proposed scheme is correct and valid.