Basic study on acoustic noise of polluted insulator and waveform analysis method

A partial discharge appears when the surface of a transmission line insulator is polluted by an adhesion of a sea salt. A corona noise is made due to the occurrence of the partial discharge on the insulator. The purpose of this research is to develop a monitoring system of the corona noise. To develop the monitoring system, we must investigate the relationship between the corona noise level and the polluted condition of the insulator and establish the measurement technique of the corona noise. This paper describes mainly about the characteristics of the corona noise waveform and the detection of the corona noise from the measured sound in the outside. As a result, we found that the frequency band of the corona noise generated by the partial discharge was 1 kHz - 6 kHz and the corona noise could be extracted in the band of 1 kHz - 2 kHz from the analysis using FFT and wavelet transfer. The occurrence of the partial discharge took an influence in the atmospheric humidity from the analysis of the measured corona noise near the transmission tower.