Adaptive Three-Phase Autoreclosing on Multi-Circuit Lines with Real Time Evaluation of Short Circuit Existence

The substantial amount of autoreclosing into existing faults stimulates activity to improve autoreclosing effectiveness. For multi-circuit transmission lines one of possible solutions is based on taking into consideration the electromagnetic and electrostatic influence of the healthy circuit at open in the cycle of autoreclosing faulty circuit. In order to avoid closing into an existing fault, while retaining advantages of three-phase autoreclosing, a new adaptive algorithm of autoreclosing for a multi-circuit transmission line is suggested and investigated. The amplitude and angle of voltage, induced at the open circuit, is strongly affected by the presence of a fault. Analytical studies, limited field tests, and EMTP simulation have been performed for 115 kV, 230 kV, and 750 kV double circuit transmission lines. The results of these studies and a simulation allowed the development of a strategy for performing a three-phase autoreclosing only after the fault is cleared and the secondary arc extinguished. As a result, reclosing into an existing fault is avoided, while restoration of the normal power supply is performed with the minimum possible time interruption