基于改进线路参数模型的配网电缆单相接地测距方法

Fault Location of Single-Phase Earth for Power Cable in Distribution Network Based on Improved Cable Line Paramter Model

基于构建的考虑多阶距离无穷小的配网电缆分布参数数学模型,提出一种基于线路分布参数模型的配网电缆单相接地故障测距方法。该方法利用线路两端的电压、电流同步故障信息来定位配网电缆单相接地故障,通过最小二乘法和搜索法的仿真结果比较,选择测距精度更高的搜索法来作为测距方法。搜索法是在整条线路上从两端搜索计算零序电压值误差最小的对应距离,该距离即为实际故障距离。仿真结果表明,所提测距方法具有较高的测距精度,并且不受中性点运行方式、采样窗口、过渡电阻和故障位置的影响。

Based on the constructed distributed parameter model of power cable in distribution network in which multi-order distance infinitesimal was taken into account, a method to locate the single-phase earth fault occured in power cable of distribution network, which was based on distributed parameter model for transmission line, was proposed. Utilizing synchronous fault information involved in voltages and currents measured at both terminals of the faulty power cable line, the search method was used as the fault location method, whichadopted face-to-face search algorithm along the whole length of the cable line to decide the distance correspoding to the point where the error of zero-sequence voltage was the minimum, and this distance was the very fault distance. The search method was chosen from two fault location methods, i.e., the least square method and the search method, by means of comparing simulation results of fault location with the two methods respectively. Simulation results showed that the proposed method could provide a higher accuracy of fault location and was independent of neutral point operation mode, sampling window, transition resistance and fault position.