Application of S Transform for Time-Frequency Analysis of Partial Discharge Signals in Power Cables
Guo Canxin1, Yong Ming2, Xu Minhua3, Li Qing4, Yao Linpeng1, Qian Yong1, Huang Chengjun1, Jiang Xiuchen1
1. Shanghai Jiaotong University Shanghai 200240 China 2. Wuxi Power Supply Company Wuxi 214061 China 3. Shanghai Extra High Voltage Power Transmission Company Shanghai 200063 China 4. Henan Electric Power Research Institute Zhengzhou 450052 China
Abstract：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.
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2010, Vol. 25 
