四分支输电线路的故障测距方法探讨

Fault Location for Four Branch Transmission Lines

针对四分支线路电力网络结构,在正序网络下,分别利用各端的电压电流推算求得T或W接点正序电压,根据所求的接点电压的相互关系,提出了故障支路的判别方法。进一步进行网络等效计算,从而将四分支线路等效为双端线路,利用当且仅当在故障点从两端计算的电压相等进行测距。ATP-EMTP仿真结果表明,该方法在各种故障类型下均能正确可靠的判别故障支路,测距精度高,无需故障前数据,理论上不受过渡电阻的影响。且在T或W接点附近故障时,无测距死区。

Four branch transmission lines is the basic unit of complex and flexible power grid network,which is the basis for Smart Grid.In this paper,the positive sequence voltages of node T or W is obtained by using voltage and current of nodes M,N,P and Q,respectively.According to the relationship of node voltages,the fault branch identified method is proposed.Then the four branch line is equivalent to a double-end line by further calculating.At the fault point,the voltages are the same,which are calculated by using voltage and current of each end.So the fault can be located accurately.Results of simulation based on EMTP indicate that the proposed method can identify the fault branch correctly and reliably.The fault location accuracy is independent of fault resistance and fault type.In addition,pre-fault data is not required.Furthermore,the proposed method solves the problem that there is a dead zone of fault location near the T or W node.