适用于平行双回线路的零序距离继电器研究

Study of the double lines distance relay based on zero sequece components

提出了适用于平行双回线路的零序距离继电器新判据。研究表明,当本回线路发生单相接地短路时,在通过公式计算得出的一特定值为正时,离保护安装处越远,本回线路零序电流与非故障线路零序电流相位差值越小;当另一回线发生单相接地短路时,离保护安装处越远,本回线路零序电流与故障线路零序电流相位差值越大,该值为负时则反之。因此可以利用双回线路中的零序电流相位差值的变化趋势来识别故障线路。由于采用零序电量作为判断依据,新方法具有受两侧电源角度的影响小,且受负荷、系统运行方式的因素影响小的特点。大量ATP仿真试验证明新方法对于双回线出现的单相接地故障,具有足够的灵敏度。

A double lines distance relay based on the zero sequence components is presented. By study, we can know that when one-phase ground fault happens on the line, more far the fault location is from where relays place, more less is the difference of the two zero sequence currents, while when one-phase ground fault happens on the other line, more far the fault location is from where relays place, more is the difference of the two zero sequence currents. So the line which the one-phase ground fault take place can be discriminated by these. It has the characteristics of fault component relays such as being immune to the load and the system operating mode and the zero sequence components required by the relay can be easily acquired and available for a long time. The theory analysis and ATP-EMTP simulation results show the distance relay have excellent performance in detecting the double lines when one-phase ground fault take place.