一种基于Prony算法的直流配电网电缆故障定位方法

Novel method of locating cable fault in DC distribution based on Prony algorithm

直流配电网电缆发生短路或接地故障时,直流断路器将故障区间隔离,此时为尽快排除故障恢复供电,需要快速确定故障点的位置。本文根据配电线路特征使用RL简化线路模型分析故障回路,提出在故障区间始端投入一个小型电容用于向故障回路放电,电容、线路和故障点过渡电阻形成一个串联的二阶电路,该二阶电路的特征频率和衰减系数反映了回路参数。利用Prony算法提取电容放电电流的特征频率和衰减系数,可以确定故障回路参数,得到故障距离。为避免线路电感分布不均影响定位精度,本文提出采用双端测量法消去线路电感,利用电阻参数计算故障距离。在Matlab/Simulink工具箱中搭建了仿真模型,仿真结果验证了该方法的有效性。

When short circuit fault or single-pole-to-ground fault occurs in the DC distribution system, the fault section will be isolated immediately by DC circuit breaker. To restore the power supply quickly, it is necessary to find out the fault point as soon as possible. Based on the features of DC distribution lines in transient process, the RL model is applied to analyze the fault loop. This paper proposes to put a capacitor with initial voltage into the ter- minal of the fault section to form a second order circuit. The characteristic frequency and decaying coefficient of the capacitor discharging current reflect the parameters of the fault loop. The Prony algorithm is used to withdraw the characteristic frequency and decaying coefficient of the capacitor discharging current. The fault distance is further calculated with the parameters of the fault loop. Two-end measurement is carried out to eliminate the inductance, a- voiding the errors caused by the non-uniform distribution of line inductance. A simulation is carried out in the Sim- ulink/Matlab environment and the results verify the accuracy of the fault location algorithm.