Wavelet-Based De-Noising Method to Online Measurement of Partial Discharge

The extraction of partial discharge (PD) signals from excessively noisy environment is crucial to on-line PD measurement. Recent research shows that the wavelet transform (WT) has achieved good effect in noise rejection in PD on-line detection. This paper presents some vital issues of WT implementation in extracting PD signals, including optimal mother wavelet selection, decomposition level selection, threshold rule determination, and thresholding function selection. The anti-noise effect of this de-noising method is proved by simulated and field detected data.