基于Spectrogram谱图局部放电窄带干扰信号抑制方法  

Spectrogram-based Method for Suppressing Narrow-band Interference Signal in Partial Discharge

作　　者：张家源 胡岳[1] Zhang Jiayuan;Hu Yue(College of Electronic Information and Electric Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学电子信息与电气工程学院,上海200240

出　　处：《电气自动化》2020年第3期55-58,共4页Electrical Automation

基　　金：国家自然科学基金(51777122)。

摘　　要：干扰抑制是局部放电信号处理的重难点。窄带干扰作为一种最常见的干扰形式,常将局部放电脉冲信号完全淹没。为在噪声中有效提取微弱的局部放电脉冲信号,提出一种基于Spectrogram谱图窄带干扰抑制方法。对原始信号做短时傅里叶变换(short-time fourier transform,STFT),并将时间-频率-功率密度三维信息绘制成谱图。借助该谱图颜色分布,即由特定谱功率密度突变确定局部放电脉冲起始时刻,从而分离检测时段内不含局部放电脉冲的时段,即噪声干扰段,进而基于该段的功率谱分布提取阈值,在频域上设计数字滤波器,对全检测时段进行干扰抑制。仿真和实测信号的处理结果均表明方法具有很好的干扰抑制效果。Interference suppression is a key and difficult point in the processing of partial discharge signal.Narrow-band interference,as a common interference form,tends to overwhelm partial discharge pulse signal completely.A Spectrogram-based narrow-band interference suppression method was presented in this paper to abstract weak partial discharge pulse signal effectively from the noise.According to this approach,short-time Fourier transform(STFT)was applied to original signal,and the three-dimensional information about time,frequency and power density was depicted in Spectrogram.With help of its color distribution,the start time of the partial discharge pulse signal was determined from the jump of the particular spectrum power density,so that the time span containing no partial discharge pulse,namely noise interference span,was separated from the detection time span.Furthermore,based on the power spectrum distribution of this section,the threshold valve was abstracted,and a digital filter was designed in the frequency domain to realize interference suppression over the entire detection time span.Both of simulation and processing results of measured signal showed that the proposed approach produced good effect of interference suppression.

关 键 词：局部放电 周期性窄带干扰 干扰抑制 数字滤波 

分 类 号：TM835[电气工程—高电压与绝缘技术]