基于VMD-SWT联合算法的谐波/间谐波检测

针对现有电力系统谐波/间谐波检测方法中提取精度不高、对噪声敏感的问题,提出一种基于变分模态分解VMD(variational mode decomposition)和同步挤压小波变换SWT(synchrosqueezing wavelet transform)的谐波/间谐波检测新方法。首先对含有谐波/间谐波的信号进行连续小波变换,得到小波量图确定分量个数。利用VMD自适应地将信号分解成多个模态分量,筛选出所选模态中心频率附近的小波系数进行SWT挤压重组锐化时频图,获得小波脊线,从而提取各谐波模态瞬时频率和幅值。仿真和实际数据表明,该方法在噪声环境下依然可以准确提取各个谐波分量,具有较高的检测精度。

Harmonics/Interharmonics Detection Based on VMD-SWT Joint Algorithm

Aimed at the problem of low accuracy and high sensitivity to noise in the existing detection methods for harmonics/interharmonics in power systems, a novel harmonics/interharmonics detection method based on variational mode decomposition (VMD) and synchrosqueezing wavelet transform (SWT) is proposed. First, continuous wavelet transform is performed on the signal containing harmonics/interharmonics, thus determining the number of components by the wavelet map. Then, VMD is used to adaptively decompose the signal into multiple modal components, and the wavelet coefficients near the center frequency of the selected mode are squeezed by SWT and recombined to sharpen the time-frequency curve, thereby obtaining the wavelet ridges to extract the instantaneous frequency and amplitude of each harmonic mode. Simulation and actual data show that the proposed method can also accurately extract the harmonic components even in a noise environment and has high detection accuracy.