Permanent faults identification method for three-phase autoreclosing based on capacitance parameter

A novel three-phase adaptive reclosure scheme using capacitance parameter identification for transmission lines with shunt reactors is developed so as to improve the interconnected system transient stability and power supply reliability. The scheme uses T type equivalent model of aerial mode component of transient fault as the prototype and current of shunt reactors as known quantity, and takes the capacitance of transmission lines as the unknown parameters to evaluate the difference between calculated capacitances and actual ones for distinguishing the transient and permanent fault. In the case of transient fault, the capacitance difference is minute because the actual fault model is consistent with the prototype. But in the case of permanent fault, the capacitance difference is distinct because the actual fault model is inconsistent with the prototype. EMTP simulation results show that the proposed scheme can reliably and effectively distinguish permanent fault from transient fault, and apply to the three-phase adaptive reclosure in transmission lines with shunt reactors.