改进的希尔伯特-黄变换在电力谐波中的应用研究

摘要

重点研究了希尔伯特-黄变换(HHT)在电力系统谐波中的应用.与现有的FFT和小波变换等电力谐波分析方法相比,HHT具有适合分析非平稳信号、自适应能力强和无基函数选择等优点,但是该算法在应用过程中存在端点效应、模态混叠等问题,一定程度限制了算法的应用及发展.提出RBF-点对称延拓方法以改善HHT的端点效应问题,然后针对模态混叠现象提出先使用陷波滤波器对信号进行预处理,再进行HHT分析.仿真结果表明改进后的HHT方法不但能有效抑制端点效应,还可以在信号基波频率能量很大时仍保证较高的分析精度.%This paper focuses on the application of Hilbert-Huang Transform approach to harmonic analysis in power system. Compared with FFT and wavelet transform, HHT has advantages such as being good at analyzing non-stationary signal, good adaptive ability and inexistent choice of basis functions. However, the approach has end effects and mode mixing which limit its application and development. In this paper, RBF-point symmetric extension method is proposed to improve the end effects. And for the mode mixing, notch Miter is used to preprocess the signal, and then HHT analysis is conducted. Simulation indicates that the improved HHT not only effectively suppresses the end effects, but also ensures good accuracy when fundamental frequency energy of the signal is large.