Analysis and Prevention of Differential Protection Misoperation of Out-of-Area Fault Line Caused by Inconsistent Current Circuit Wiring on Both Sides of a Line

Based on the analysis that the fault outside the area caused by inconsistent current circuit wiring on both sides of A line leads to misoperation of differential protection of the line, the reason is that the protection device on one side of the line adopts phase A and C current as the local protection current, and the other side of the line adopts phase A, B and C current as the local protection current. The protection device on both sides of the line does not alarm or operate, which causes the differential protection on both sides of the line to operate incorrectly when the fault occurs outside the area. Through case analysis, the relevant countermeasures and handling methods are introduced to provide reference for the subsequent handling of similar incidents.