零序互感对相邻线路纵联零序方向保护的影响

Effects of zero-sequence mutual inductance on zero-sequence pilot protection of parallel lines

就零序互感对相邻线路纵联零序方向保护的影响进行了分析。采用互感线路一般模型,结合零序方向元件的动作原理,分别在发生内部故障和出口处反方向故障的情况下,对纵联零序方向元件的动作行为进行了详细的理论推导。研究表明,不论本线路发生内部故障或出口处反方向故障,该线路纵联零序方向保护不受零序互感的影响,能够正确动作;与其相邻的互感线路纵联零序方向保护是否误动,取决于两互感线路间电气联系的紧密程度,电气联系越强,误动可能性越小。利用PSCAD进行了仿真验证。

Effects of mutual inductance on zero-sequence pilot protection of parallel lines are analyzed.Using a general model of mutual inductance lines and combining with the operating principle of the zero-sequence directional element,a detailed theoretical analysis is carried out on the actions of zero-sequence pilot protection under the conditions of inner fault and fault at the exit in the opposite direction.Studies show that in the case of internal fault or fault at the exit in the opposite direction,the zero-sequence directional protection of the fault line is immune to the impact of zero-sequence mutual inductance,and can operate correctly;the maloperation of the zero-sequence pilot protection of its parallel line depends on the tightness extent of electrical connection between the two mutual lines,the stronger the electrical connection is,the smaller the possibility of malfunction will be.At last,PSCAD simulation is carried out.