基于EMD的Hilbert变换应用于暂态信号分析

Apply Empirical Mode Decomposition Based Hilbert Transform to Power System Transient Signal Analysis

将一种新的非平稳信号处理方法--基于经验模态分解(EMD)的希尔伯特(Hilbert)变换方法,应用于电力系统暂态信号分析中。通过EMD方法提取信号的固有模态函数(IMF),再进行Hilbert变换,求瞬时频率、瞬时振幅,得到信号的Hilbert谱,进而得到Hilbert边际谱,对故障暂态和扰动信号进行了分析。通过瞬时频率进行故障暂态和扰动时刻的准确检测;通过Hilbert边际谱与傅里叶幅值谱的比较,表明Hilbert边际谱在分辨率上具有明显的优越性。该方法为电力系统暂态信号分析提供了一种新的分析手段。仿真结果验证了该方法的有效性。

Empirical mode decomposition (EMD) based Hilbert transform (HT), a new method for processing nonstationary signals, is applied to analyze transient signal in electric power systems. The signal is firstly decomposed into intrinsic mode function (IMF) by the EMD method. Then Hilbert spectrum and Hilbert marginal spectrum are obtained from instantaneous frequency and amplitude obtained from Hilbert transform. Thus the transient and disturbances caused by fault can be analyzed and further detected accurately through the instantaneous frequency. Compared with Fourier amplitude spectrum, Hilbert marginal spectrum has higher resolution in frequency domain. The simulation result shows that the proposed method is effective.