基于双端量的半波长交流输电线路故障选相方法

Scheme of Fault Phase Selection in Half-wavelength AC Transmission Line Based on Two-terminal Electrical Quantities

半波长交流输电线路电压等级高,故障后需要选相跳闸。但是半波长输电线路独特的电气特征使得传统的故障选相方法不再适用。文中提出了一种基于双端电气量的半波长交流输电线路故障选相方法。将两端相间电压、相间电流进行组合变换,换算到短路点正负序短路电流,从而判断故障相。基于电磁暂态仿真软件PSCAD搭建特高压半波长输电线路仿真模型。仿真结果表明,该故障选相方法不受故障位置、过渡电阻、弱馈等因素的影响,在半波长交流输电线路发生短路故障时,能快速正确地实现故障选相。

Half-wavelength AC transmission line (HWACT)is a high-voltage transmission line.So,it needs to cor- rectly choose the fault phases after short circuit occurred in HWACT.Due to its unique electrical characteristics,the traditional phase selection element no longer applies.This paper proposes a scheme of fault phase selection in HWACT based on two-terminal electrical quantities.Two-terminal line voltage and two-terminal line current can be converted into positive and negative sequence of short circuit current,and then it can correctly choose the fault phas- es.The fault phase selection scheme is not affected by fault location,fault resistance and weak-infeed line.PSCAD simulation shows that the scheme can select the fault phase selection quickly and correctly.