利用线路中点电流检测的改进单端行波故障测距方法

Improved Method for Fault Location of Single-ended Traveling-wave Using Line Midpoint Current Measurement

现有的输电线路单端行波故障定位方法存在难以确定反射行波来源的问题。双端法需要在线路的两端安装故障检测装置,虽然克服了单端法的缺点,但测距精度受到时间同步误差的影响。该文提出了一种利用线路中点电流检测的改进单端行波故障定位方法,该方法通过在线路的中点处安装电流传感器,应用皮尔逊相关系数比较线路端点和中点的故障电流信号,确定故障点所在的区间。通过分析线路中点电流传感器记录的故障电流,可以在线计算得到没有时间同步误差的行波传播波速。然后根据故障区间信息选用相应的单端法故障测距计算式,代入测得精确的波速,即可得到精度好、可靠性高的故障测距结果。该方法适用性好,对于已有单端行波测距装置的线路,只需要在线路中点处添加一套线载电流传感器,硬件成本较低,应用前景良好。

It is difficult to distinguish the sources of reflected waves by existing single-ended traveling-wave-based fault location methods.Double-ended methods need signals at both ends,although they overcome the disadvantages that single-end methods have,the accuracy of fault location result is affected by the time synchronization error.An improved traveling-wave-based single-ended method using line midpoint current is proposed in this paper.The method makes use of the measuring device at one end,installs the wire-based current sensor at the midpoint of the line,and determines the faulty segment by comparing the current recorded at these two positions.The time instants of wave arriving at the line midpoint are analyzed,and the precise value of wave propagation speed can be obtained.Then,according to the information of faulty segment,the corresponding single-ended based fault location equation is applied.The obtained wave propagation speed is substituted into an equation,so that the fault location results with good accuracy and high reliability can be calculated.This method is applicable to various voltage levels.For lines with single-ended traveling-wave fault location devices,only one set of wire-based current sensor is added,the increased hardware cost is low,and the application prospect is good.