基于高频零序电流幅相归一的分布式电网单相接地故障选线方法

A single-phase earth fault line selection method in distributed power system based on the unity of amplitude and phase of high frequency zero-sequence current

针对分布式电源配电网故障选线中判据求取复杂、选线步骤繁琐等问题,提出一种EEMD算法与三次样条插值法相结合提取零序电流暂态高频分量幅相归一判据的故障选线方法。利用EEMD算法自适应地将零序电流分解为若干个模态函数分量(IMF),采用三次样条插值法对IMF1进行包络处理,实现高频分量幅值相位信息归一,通过观察幅相归一包络线的第一特征峰值实现故障选线。仿真结果表明,该方法步骤简洁,选线快速准确,不受接地电阻、故障电压相位角等条件影响。

According to the problems for criterion calculation and complicated for selection steps in distribution network with DG, a new fault line selection method is presented. This method combines ensemble empirical mode decomposition （EEMD） and cubic spline interpolation （CSI） method to obtain amplitude-phase-unity criterion of transient high frequency components of zero-sequence current. The zero-sequence current is decomposed into several intrinsic mode function （IMF） components by EEMD algorithm. For obtaining amplitude-phase-unity criterion of high frequency component, the envelope curve of the first IMF component is drawn by CSI method. The fault line can be selected by observing the first characteristic peak of am- plitude-phase-unity envelope curve. Simulation analysis shows that this method is simple and accuracy for selecting the fault line at a high running speed. It is free from the influence of conditions such as the fault resistor and fault phase angle of voltage.