Research on White Noise Interference Suppression of GIS Partial Discharge On-line Monitoring Based on Improved Wavelet Threshold

Abstract

In order to solve the problem that polymorphic partial discharge pulse signal is interfered by white noise when on-line monitoring partial discharge in gas insulated switchgears(GIS),a new threshold function of arbitrary order is constructed based on the existing wavelet threshold algorithm. It overcomes the discontinuity of hard thresh- old function and the problem of constant deviation of soft threshold function is improved. By constructing the polymor- phic partial discharge signal under the interference of white noise,the signal noise ratio(SNR)and the mean square error(MSE)are used as the noise reduction evaluation index it is found that the method is more effective to suppress noise interference by comparing and analyzing the traditional wavelet denoising algorithm based on the hard thresh- old and the soft threshold. Finally the improved threshold algorithm is validated to be suitable for on-line monitoring system of partial discharge in GIS by field simulation corona discharge model experiment.