Application of a New Kind of Wavelet Threshold De-Noising Method in Partial Discharge Signals

In order to more effectively remove noise in partial discharge signals, it is proposed a new threshold selection method in this paper. This method firstly takes the signals before the partial discharge starting to happen as only contain noise signal, and then applies a wavelet transform to the only contain noise signal. Secondly record every detail part and the maximum value of wavelet coefficients of last layer approximation part, and take this value as its layer threshold. And then applies a wavelet transform to the partial discharge signals which contains noises. Next is to process wavelet coefficient of each layer using the selected threshold. Finally, the already handled wavelet coefficients is used to reconstruction the signals. The whole process of threshold choosing is automatic without human intervention. Simulation experiment show that compared with the traditional threshold selection method, this method can be better to remove the noise of the partial discharge signals, and it has a strong practical value.