基于EMD-相关性算法的谐振接地系统故障选线新方法

摘要

为准确选出谐振接地系统单相接地故障线路,提出了基于EMD算法与相关性理论相结合的故障选线新方法.根据谐振接地系统发生单相接地故障时故障线路与健全线路暂态零序电流之间的差异,用EMD算法对各馈线零序电流的暂态故障分量数据进行分解,提取其主振荡频带信息.利用故障馈线与健全馈线的零序电流主振荡频带相关性最弱的特征,对故障零序电流的主振荡频带分量在一定数据窗下进行综合相关性分析,选择综合相关系数最小对应的馈线为故障馈线.大量仿真结果表明该选线方法准确、可靠.%In order to choose accurately the single-phase-to-ground fault line in resonant earthed system, a new method of detection based on the EMD (Empirical Mode Decomposition) algorithm and the correlation was proposed. When the resonant earthed system occur single-phase-to-ground fault, the differences occurs between fault line and perfect line transient zero sequence. The feeder zero sequence current transient fault component is decomposed with EMD algorithm, and gets its main oscillation frequency information. According to the weak correlation characteristics of fault feeder and the perfect feeder zero sequence current main oscillation frequency, fault zero sequence current main oscillation frequency component can be analyzed about comprehensive correlation. Thereby, the minimum comprehensive correlation coefficient is corresponding to the fault feeder. Simulation results show that the method is accurate and reliable.