同杆双回线反序电流特点及其在T形线路测距中的应用

对同杆双回线的反序电流特性进行了研究，推导出双回线中存在其他支路时反序电流的计算公式及特点。该计算公式可以应用到带有同杆双回线的T形线路的故障支路判断和故障测距，利用反序正序电流计算反序正序电压，并且利用反序正序电压在故障点相等的等量关系进行故障测距。大量的EMTP仿真结果表明，所给出的支路电流与同杆双回线反序正序电流之间的关系是正确的，并且在带有同杆双回线的T形线路故障测距中显示出较大的优势。该测距方法的精度不受故障支路、故障类型、系统运行方式、故障点过渡电阻等因素的影响。

A Faulted Line Selection Method of Parallel Transmission Teed Line on the Basis of Differential Current

Based on distributed parameter model and analysis of differential sequence circuit in Teed line, an accurate fault location algorithm for Teed line is described. Common components and differential components are introduced into the algorithm to decouple mutual electromagnetic effect between lines. Because the differential sequence voltages at fault position are equal, equation can be founded on the basis of analyzing differential positive sequence current. The result of EMTP simulation indicates that the proposed algorithm is not affected by fault resistance and system operating mode. It can also be applied in asymmetrical parallel transmission lines.