A Wavelet De-Noising Method for Power Quality Based on an Improved Threshold and Threshold Function
Wang Weibo1, Dong Ruiying1, Zeng Wenru1, Zhang Bin1, Zheng Yongkang2
1. School of Electrical and Electronic Information Xihua University Chengdu 610039 China; 2. State Grid Sichuan Electric Power Research Institute Chengdu 610072 China
Abstract：There are many types of power quality disturbance signals, the components are complex, and the disturbance characteristics are easily removed as noise. For these problems, an improved wavelet threshold de-noising algorithm was proposed in this paper. This algorithm could determine the noise by calculating the peak-to-sum ratio for each layer of wavelet coefficients, so that the correction factor Fj could adaptively adjust the general threshold according to the noise distribution characteristics of different disturbance signals. Meanwhile, an improved threshold function was proposed, which could adjust the soft and hard characteristics by changing the value of the parameter a to determine the appropriate threshold function. The improved algorithm was used to de-noise the seven kinds of power quality signals. The simulation results show that the improved algorithm achieves better signal-to-noise ratios, stable de-noising effects and better waveforms of reconstructed signals for various types of disturbance signals in different noise interferences. Moreover, it retains the disturbance characteristics in the de-noising process, which can provide accurate and effective information for the subsequent power quality analysis.
王维博, 董蕊莹, 曾文入, 张斌, 郑永康. 基于改进阈值和阈值函数的电能质量小波去噪方法[J]. 电工技术学报, 2019, 34(2): 409-418.
Wang Weibo, Dong Ruiying, Zeng Wenru, Zhang Bin, Zheng Yongkang. A Wavelet De-Noising Method for Power Quality Based on an Improved Threshold and Threshold Function. Transactions of China Electrotechnical Society, 2019, 34(2): 409-418.
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2019, Vol. 34 
