基于集合经验模态分解的局部放电信号的窄带干扰抑制

摘要

采用经验模态分解(EMD)方法抑制局部放电的窄带干扰时,由于EMD方法本身存在模态混叠问题,在含有局放成分的模态固有函数中仍可能同时含有一定量的窄带成分,导致局放信号无法提取.分析了在局放信号上叠加不同幅值、不同频率的窄带干扰条件下的EMD混叠现象,并提出了基于集合经验模态分解(EEMD)的解决方法.该方法对单频率成分和多频率成分的窄带干扰,均能较好地提取出局放信号.并针对EEMD引入的白噪声干扰,提出了自适应阈值的抑制方法,取得了较好的结果.仿真和现场测试的结果均验证了所提方法的有效性.%Due to the mixed mode phenomena of the empirical mode decomposition (EMD) method, partial discharge (PD) component may mix with narrow-band component in the instinct mode function so that it is hard to extract PD signals from narrow-band interferences. This paper shows that it is an inherent problem with mixed mode phenomena under the condition of adding different amplitude or different frequency narrow-band interference. EEMD method is introduced to separate the PD signals from the narrow-band interferences of a single frequency or multi-frequency. An adaptive threshold method is given to suppress the white noise added by EEMD. The proceeding result of simulation model and signal from field test proves its effectiveness.