S变换在电力电缆局部放电信号时频分析中的应用  

Application of S Transform for Time-Frequency Analysis of Partial Discharge Signals in Power Cables

作　　者：郭灿新[1] 勇明[2] 徐敏骅 李清[4] 姚林朋[1] 钱勇[1] 黄成军[1] 江秀臣[1] 

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 [2]无锡供电公司生产技术部,无锡214061 [3]上海超高压输变电公司,上海200063 [4]河南电力试验研究院,郑州450052

出　　处：《电工技术学报》2010年第11期9-14,共6页Transactions of China Electrotechnical Society

摘　　要：针对电力电缆局部放电检测,介绍了基于新型S变换的时频分析方法,用于提取及分辨淹没在现场噪声干扰中的局放脉冲信号。局放信号是典型非平稳信号,单纯使用时域或者频域信息都不能很好地表示奇异信号的时变信息。最近发展的S变换是连续小波变换和短时傅里叶变换的一种结合与延伸,引入了幅度和宽度均随频率变换的高斯窗,具有与频率相关的渐进分辨率特性。局放信号的S变换图谱,在信号高频分量部分获得较高的时域分辨率,而在低频分量部分获得较高的频域分辨率,并可提取局放脉冲发生时刻及信号中心振荡频率等特征信息。对仿真信号和现场采集的电力电缆接地线上的局放信号应用S变换进行时频分析,并与短时傅里叶变换及Gabor变换等传统时频分析方法比较,结果显示S变换的时频分析可有效获取局放脉冲信息。For partial discharge detection in power cables,a new-type S transform time-frequency analysis method is introduced to distinguish the partial discharge signals from field noise.Partial discharge signal is a typical non-stationary signal,and its characteristics can not be clearly expressed only by time-domain or frequency-domain information.S transform is a combination and extension of continuous wavelet transform and short time Fourier transform（STFT）.The S transform method employs a Gauss window,whose amplitude and width change with frequency.S transform achieves better time resolution in high frequency proportion,and better frequency resolution in low frequency proportion.Compared with traditional time-frequency representation like STFT and Gabor transform,the S transform is used to analyze the simulation and on-site detection signals from power cables earthing strap.The results show that S transform is effective in extracting partial discharge characteristic information.

关 键 词：电力电缆 局部放电 S 变换 时频分析 脉冲特征 

分 类 号：TM247[一般工业技术—材料科学与工程]