New method of power quality de-noise based on improved MDL criterion

The power quality signals corrupted by large mount of noise can greatly affect the result of detection in power system. In order to erase the noise efficiently, this paper improves the algorithms based on Minimum Description Length (MDL) criterion. The second term in MDL function is changed to the signal's retained energy ratio, which can improve the ability to de-noise, and then the corresponding parameters in elevated MDL are given. Moreover, the wavelet basis function selection and the decomposition levels are discussed in detail. The method can obtain optimal mother wavelet and level. The de-noised signals have high either signal-to-noise ratio or the retained energy. Simulation result proves that the method in this paper is superior to the wavelet and MDL based de-noising method, and the result is satisfaction.