Characteristics and Applicability of Line Selection of Non-solidly Grounding Fault in Paralleling Double-Circuit Distribution Lines on Different Buses

Abstract

To improve power supply capacity and save land resources, a large number of single-circuit distribution lines have been transformed into double-circuit distribution lines. The influence of their complex coupling relationship on the characteristics of non-solidly grounding faults and the applicability of existing line selection methods are not yet clear. An equivalent model of small grounding fault in double-circuit line from different buses is established, and the influence of the line-to-line coupling on the fault characteristics of the grounding system and the applicability of the line selection methods are analyzed by it. The results show that: for the system with a grounding fault, the line-to-line coupling does not affect its zero-sequence voltage and current characteristics, and the existing line selection methods are still applicable; for the system without a grounding fault, the double-circuit line shows the characteristics of the faulty line, and the existing line selection methods are no longer applicable. Simulation is used to verify the results.