采用HHT的单相接地故障电流与励磁涌流辨识

为有效辨识中压配电网单相接地故障电流与变压器铁芯饱和产生的励磁涌流相似波形，提出一种基于希尔伯特 黄变换（HHT）经验模态分解（EMD）的辨识方法。通过对故障电流和励磁涌流进行EMD特性分析，将原始信号分解为若干本征模态函数（IMF）分量，根据确定的主导IMF分量个数以及比重系数和阈值的关系，区分出故障电流和励磁涌流的波形。仿真发现，单相接地故障电流主导的本征模态函数分量仅有1个，而励磁涌流主导的IMF分量则有多个；故障电流的比重系数Ki远大于励磁涌流的Ki。仿真结果表明，该方法能够有效辨识故障电流和励磁涌流。

Identification of Fault Current and Excitation Inrush Current Based on HHT

An empirical mode decomposition method(EMD) based on Hilbert Huang transform(HHT) is proposed for effective identification of the similar waveforms of the single phase ground fault current in the medium voltage distribution network and the excitation inrush current generated by the transformer core saturation.By analyzing the EMD features of the fault current and excitation inrush current, the original signal was decomposed into several intrinsic modal function (IMF) components, and waveforms of fault current and excitation current were identified according to the number of dominant IMF components and the relationship between the specific gravity coefficient and the threshold surge wave determined.Simulation results show that while there is only one IMF component for fault current, there are many for excitation inrush current, and specific gravity coefficient Ki for fault current is much greater than that for excitation inrush current.This approach makes effective identification of the two.