When a ground fault occurs on double-circuit transmission lines,the conventional tripping strategy may inject negative-sequence components into the system. The traditional autoreclosing scheme does not determine the fault feature before the reclosing,and the stability of the power system will be affected if the reclose fails. To solve the above problems,an improved tripping strategy suitable for ground faults on double-circuit transmission lines is proposed,where phase-separation adaptive autoreclosing is used in the tripping strategy. Firstly,by establishing and analyzing the phase-to-phase coupling model of double-circuit transmission lines,an improved tripping strategy that can avoid the injection of negative-sequence components into the power system is proposed. Secondly,the capacitive coupling voltage characteristics are analyzed under transient and permanent faults respectively,and the fault feature identification criteria based on the capacitive coupling voltage of double-circuit transmission lines is proposed. Finally,the improved tripping and closing strategy are combined to form a phase-separation adaptive autoreclosing strategy suitable for ground faults on double-circuit transmission lines. The PSCAD/EMTDC simulation verifies that the proposed phase-separation adaptive autoreclosing strategy can avoid the injection of negative-sequence components into the system and ensure the reclosing success rate of the transmission line under different ground fault types,fault locations and transition resistances.
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