Power quality disturbance signals de-noising based on improved soft-threshold method

Recently, power quality issues have captured more attentions. It is necessary to monitor power quality in order to analyze and evaluate it. But noises will influence the signals during data collection. It is hard to analyze signals correctly. Soft-threshold de-noising method based on wavelet transform is effective. This paper proposes an improved soft-threshold de-noising method based on 3 sigma principle of normal distribution, typical power quality disturbance signals are simulated, and detect the reconstructed signals disturbance. Comparing with universal soft-threshold de-noising method, simulation results show that detection accurate rate is improved by this method.