基于改进经验小波变换的高压电缆局部放电噪声抑制研究

Research on Suppression of Partial Discharge Noise of High Voltage Cable Based on Improved Empirical Wavelet Transform

对高压电缆的局部放电(PD)进行监测,并对其所包含的噪声信息进行抑制,是一种有效的绝缘评估方法。针对PD信号所包含的复杂噪声信息,提出一种基于改进经验小波变换(IEWT)的噪声抑制方法。该方法以IEWT分解为核心,通过将含噪信号分解为按频率顺序排列的经验小波函数(EWF),有效避免复杂噪声信号分解时的模态混叠现象。利用峭度规则对分解得到的EWF进行筛选,最后对筛选出的有用EWF进行重构和降噪处理,达到对复杂含噪信号的噪声抑制效果。模拟仿真以及现场测试表明,与现有基于EWT和基于EMD的降噪方法进行对比,该文所提方法可更有效地抑制PD信号所包含的噪声信息。

Monitoring the partial discharge(PD)of high-voltage cables and suppressing the noise information contained in it is an effective insulation evaluation method.Aiming at the complex noise information contained in PD signals,a noise suppression method based on improved empirical wavelet transform(IEWT)is proposed.It takes IEWT decomposition as the core,by decomposing noisy signals into empirical wavelet functions(EWF)arranged in order of frequency,effectively avoids the modal aliasing phenomenon during the decomposition of complex noise signals.The kurtosis rule is used to filter the EWF obtained by decomposition,and finally reconstructing and reducing noise of the selected useful EWF,the noise suppression effect of complex noisy signals is achieved.Simulation and field tests show that,compared with the existing noise reduction methods based on EWT and EMD,the method proposed in this paper can more effectively suppress the noise information contained in the PD signal.