摘要
为给气体绝缘系统(GIS)局部放电在线监测和诊断提供重要的理论依据,介绍了近年来国内外利用小波变换分析局部放电信号技术的研究状况,提出了利用小波分析局部放电信号的一般方法即采用相关系数法选择最佳小波,选择恰当的分解层,利用自动阈值法确定阈值,在此基础上对局部放电信号做小波、小波包分析,并与模糊理论、神经网络等技术结合来完成局部放电信号的模式识别。
Studying the partial discharge signals can provide the important theory basis for on-line monitoring and diagnosis of gas insulated substation （GIS） partial discharge. The wavelet transform technique is an efficient way to analyze the partial discharge signals. By studying and researching how the domestic and international scholars used the wavelet to analyze the partial discharge signals recent years, a general method for analyzing the partial discharge signals by wavelet transform is summarized. Firstly, the optimal wavelet can be selected by calculating the cross correlation coefficient 7 between the partial discharge waveform and each wavelet waveform, the optimal wavelet for the partial discharge waveform is the one with the maximal value of 7. Secondly, the level of decomposition must be selected suitably. Thirdly, the threshold is selected by the automatic threshold rule, after that, the partial discharge is denoised by combining the ＂soft＂ and ＂hard＂ thresholding. Lastly, partial discharge signals can be analyzed by wavelet and wavelet packet, such as denoise, multi-resolution analysis, the wavelet packet analysis etc. In order to distinguish the partial discharge signals, the wavelet transform technique can be combined with the neural network technique, the fractal theory and the fuzzy logic and so on. thus, the type of partial discharge can be recognized. So the partial discharge signals can be analyzed by the wavelet transform technique with the method mentioned above. The optimal wavelet can be found from the DB functions in order to analyze the partial discharge signals. Above all, the basic methods Of analyzing partial discharge signals by wavelet transform technique can be learned.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2007年第8期13-17,共5页
High Voltage Engineering
基金
国家自然科学基金重点项目(50237040)
军械工程学院科研基金(YJJXM0424)。~~
关键词
局部放电
小波
降噪
阈值
滤波
信号
partial discharge
wavelet
denoise
threshold
filter
signal
