Wavelet Packet Denoising for On-Line Partial Discharge Detection in High Voltage Systems

Partial discharge (PD) measurements taken on-line are severely affected by noise due to external disturbances. In this paper a powerful noise reduction technique is employed to isolate the PDs from the noise. This technique is based on a wavelet packet denoising algorithm. A brief description of the wavelet packet theory as an extension of the multiresolution analysis is given. Results of the application of this algorithm on low signal to noise PD signals corrupted with noise, are presented, demonstrating substantial improvement in the signal recovery with minimum shape distortion