Wavelet analysis used in UHF partial discharge detection in GIS gas insulated substations

摘要

One of the most important subjects in monitoring GIS is PD detection. The issue is that the PD signal is weak and sensitive to external noise. In this paper, the experiments of detection PD in GIS using UHF technique is described. The results show that UHF method is effective in detecting PD in GIS and avoiding the disturbance of corona. Nevertheless very large corona, fluorescent tube or radio frequency noise nearby can still disturb the measurement. A method of signal processing by software is presented in this paper. Through the procedure of signal wavelet transform, signal noise extraction and signal reconstruction the signal is analyzed to determine the magnitude of PD in GIS and avoid false alarm.