Adaptive Autoreclosing Scheme for Line-to-Line Nongrounded Faults on Double-Circuit Transmission Lines Based on Phase-to-Phase Reactive Power

Double-circuit transmission lines play a very important role in electric power transmission. When a line-to-line nongrounded fault occurs on double-circuit transmission lines, for traditional tripping and reclosing methods, tripping of all six phases may cause power system instability, and fixed time autoreclosing may reclose the double-circuit transmission lines to a nonextinguished fault. In this paper, a novel tripping strategy is proposed; when a line-to-line nongrounded fault occurs, some part of the electric power can be transmitted after tripping, and many kinds of nongrounded faults can be equivalent to a single-phase to ground fault. Furthermore, reactive power characteristics are adopted to determine the fault extinction. Finally, an adaptive autoreclosing scheme for line-to-line nongrounded faults on double-circuit transmission lines based on phase-to-phase reactive power is proposed. The accuracy and feasibility of the propose method are verified by relevant simulation experiments, and multiple operation conditions are considered.