基于VMD的谐波检测方法

Harmonic detection method based on VMD

针对电网谐波检测问题,分析已提出的几种传统的谐波检测方法,首次提出一种基于变分模态分解(Variational Mode Decomposition,VMD)的电网谐波检测方法。运用VMD方法将所含谐波的电网信号分解为一系列的本征模态分量(Intrinsic Mode Function,IMF),然后对分解出的IMF分量采用希尔伯特黄变换(HilbertHuang transform,HHT),获得每一个IMF分量的瞬时频率和瞬时幅值。由于VMD方法能准确的分解出每一个IMF分量,因此所得到的瞬时频率和瞬时幅值达到了很高精度的获取,并且与在经验模态分解(Empirical Mode Decomposition,EMD)所得到IMF分量Hilbert变换进行对比,说明了该方法比传统的Hilbert变换分解能力更强。为验证该方法对电网谐波的检测能力,将VMD算法与传统的瞬时无功功率谐波检测算法运用到实测数据中。仿真和实测数据表明,该方法是检测谐波的有效新方法。

Aiming at solving the problem of harmonic detection,several traditional proposed methods have been analyzed. It was the first time that the power grid harmonic detection method based on Variational Mode Decomposition( VMD) was proposed. Electrical signals were decomposed into a series of intrinsic mode function( IMF) by using the VMD method,and then,the instantaneous frequency and instantaneous amplitude value of each IMF were gained after the transforming of IMF decomposed through Hilbert-Huang transforming( HHT). For the VMD method decomposed each IMF accurately,therefore,the instantaneous frequency and amplitude value could be obtained accurately. And after the comparison of the results of IMF gained based on empirical mode decomposition( EMD) with the results of IMF gained based on Hilbert-Huang transforming,it was proved that VMD method showed stronger decomposition ability than the traditional Hilbert transforming. In order to test the detection ability of VMD on power grid harmonics,VMD calculation and the traditional instantaneous harmonic detection were applied to practical data. Results on simulation and experimental statistics showed that the method could be regarded as an effective method to detect harmonics.