Partial Discharge Signal Denoising Based on DualTree Complex Wavelet Transform Combined with Thresholding

In high voltage engineering, it is of great importance to monitor partial discharge (PD) of critical apparatus. On-site PD signal is usually contaminated by white noise. Therefore, it is necessary to denoise the measured signal to acquire real PD. The most widely used method is the traditional wavelet thresholding. In this paper, a modified version for the traditional wavelet thresholding is proposed, i.e. dual-tree complex wavelet transform (DTCWT) is used to replace single wavelet to be combined with thresholding. Two DTCWT examples are used, i.e. dual tree wavelet pair constructed by common factor method, and dual tree wavelet pair constructed by Db family wavelets. To verify their performance, a numeric study is carried out, and the computation results show that DTCWT combined with thresholding is better than traditional wavelet thresholding.