Power quality signal denoising based on wavelet package improved threshold method
JIN Yan, ZHONG Jinjin
（College of Information Engineering, Zhejiang University of Technology, Hangzhou 310023, China）
Abstract:  In order to enhance the denoising effect of transient power quality disturbance signals, a wavelet package improved threshold denoising method was put forward. Based on analzing the denoise method of soft threshold and hard threshold, the thresold quantization fuction was improved. The new denoising method can overcome the discontinuity of the hard threshold and the offset of the soft threshold. The simulation results of transient power quality disturbance signal denoising show that the new method can not only reduce the loss of useful information while denoising, but also effectively denoise white noise under different SNRs. The denoising effect is superior to the soft threshold function.
Key words: power quality disturbance; wavelet package transform; improved threshold