基于微扰法的低压有源配电网故障定位方法

分布式电源（DG）接入低压配电网，使配电网潮流分布变得复杂，基于单向潮流的传统故障定位方案不再适用。提出基于微扰法进行相模变换实现含分布式电源低压配电网的故障定位方法。针对配电网三相线路参数不对称，运用微扰原理，通过构造线路参数阻抗矩阵微扰量，求出使原相互耦合的三相网络解耦成3个相互独立序网图的相模变换矩阵，实现了对不对称线路参数阻抗矩阵的解耦；在此基础上，对低压有源配电网依据区段故障前后相模变换电流故障分量的相角差值的变化，推导出判断配电网故障区段的判据，实现对低压配电网的故障定位。通过Matlab/Simulink进行了仿真分析，结果表明：该方法可以快速准确地定位出故障区段，解决了配电网络参数不对称对定位精度的影响。

Fault Location for Low Voltage Active Distribution Network Based on Perturbation Method

With the access of distributed generation to low-voltage distribution network, the power flow of the distribution network becomes more complicated. As a result, the traditional fault location scheme based on one-way power flow no longer applies. This paper proposes a perturbation based phase-mode transformation to achieve the fault location for low-voltage distribution networks with distributed generation. Against the asymmetry of three-phase line parameters in low-voltage distribution network, the line parameter impedance matrix perturbation is constructed with the perturbation theory to derive the phase mode transformation matrix which can decouple the original three-phase networks into three mutually independent sequence graphs, consequently realizing the decoupling of the parameter impedance matrix of asymmetric lines. And then, A criterion is derived for judging the fault section of the low-voltage active distribution network according to the changes of the fault component phase angle differences of the section phase-mode transformation current before and after the fault, realizing the accurate position of the low voltage distribution network. The Matlab/Simulink simulation results show that the proposed method can quickly and accurately locate the fault section and solves the influence of the asymmetry of distribution network parameters on positioning accuracy.