基于EEMD阈值的MOA避雷器泄漏电流去噪的研究

MOA避雷器泄漏电流中的阻性分量是反映MOA运行状态的有效特征量,但MOA通常运行在强电场和强磁场环境中,MOA避雷器在线监测系统采集的泄漏电流信号必然混叠很多噪声,不经有效的信号去噪即采用,会影响监测系统的信号处理、分析和MOA避雷器故障诊断的准确性。针对MOA避雷器泄漏电流的特点,结合通用阈值(sqtwolog)原则、启发式阈值(heursure)原则、无偏似然估计阈值(rigsure)原则和极值阈值(minimax)原则,提出了总体经验模态分解(简称EEMD)阈值去噪方法。采用均方根值、三次倍频幅值比和去噪后的波形这三个评价标准来判断EEMD阈值去噪的优劣,通过对信号仿真和现场采集的实测信号进行分析,得出基于无偏似然估计阈值原则是最佳的EEMD阈值去噪方法。

Research onSDe-noising of MOASLeakage Current Based on EEMDSThreshold

TheSresistive componentSin leakage currentSof MOA arresterScould reflect the ope-ration state of MOASeffectively,Sbut MOA usually operateSin the strong electromagnetic env-ironment,Sso the leakage current mustSmixed withSmuch ofSnoise. Using it withoutSeffective signalSde-noising will affect the accuracySof monitoring system forSanalyzing signal and M-OASfault diagnosis.SIn this paper, aiming at the characteristics of leakage current of MO-A,Scombined with theSuniversal threshold,Sthe heuristic threshold, the unbiased risk estim-ate threshold andSthe minimax threshold,Sput forward the Ensemble Empirical Mode Decomposi-tionSSthreshold de-noising methods. Though the three evaluationScriteria of root-mean-squa-re value, threeSharmonicSamplitude ratio andSde-noised waveform, judgingSthe result ofSEEM-DSthreshold de-noising. AnalyzingSsimulatedSsignal and measuredSsignal acquisitionSfrom fi-eld to get the conclusion that the method EEMD based the unbiased risk estimate threshold