基于改进注入法的直流配电网双端测距故障定位方法

Double-end Distance Measurement Fault Location Method for DC Distribution Network Based on Improved Injection Method

设计了1种主要由电感、电容、直流电源和开关组成的故障测距模块,通过调整其电容、电感的大小,使测距模块与故障线路构成欠阻尼振荡的二阶放电电路,利用非线性最小二乘拟合确定放电电流衰减的振荡频率和衰减系数,通过引入双端信息量改进了传统注入法中的故障测距算法,得出了以线路总长、测距模块电感和电容值为参数的故障距离计算公式,消除了直流线路电感和电阻对故障定位的影响。通过搭建±10 kV的10 km直流配电网模型并考虑线路分布电容和过渡电阻影响进行了仿真,且与其他方法作了比较分析,结果表明本文所提方法在考虑分布电容以及过渡电阻改变的实际情况下定位精度较高,具有实际应用价值。

A fault-ranging module consisting mainly of inductors,capacitors,DC power supplies and switches is designed. By adjustingthe capacitance and inductance,the ranging module and the faulty line forms a second-order discharge circuit with underdamped oscillation.The least squares fitting method is used to determine the oscillation frequency and attenuation coefficient of discharge current attenuation.The fault location algorithm in the traditional injection method is improved by introducing double-ended information,obtaining a fault-rangingformula with the parameters including the total length of the line as well as the inductance and capacitance of the ranging module,andeliminating the influence of DC line inductance and resistance on fault location. The 10 km DC distribution network model of ±10 k V is built.The simulation of the distributed capacitance and transition resistance of the line is carried out and compared with other methods. The resultsshow that the proposed method has better positioning accuracy when considering the transition resistance and distributed capacitance.