Frequency spectrum of various partial discharges in GIS

Before the breakdown of electrical apparatus partial discharges occur. Measuring partial discharges is very important for predictive maintenance for GIS. In a GIS, several types of defect are probable, such as a metallic particle fixed on conductors, a particle on the spacer and a moving particle. For predictive maintenance it is necessary to understand the characteristics of partial discharges for these defects. We measured frequency spectra and phase distributions for these defects using a practical bus model and made the characteristics of partial discharges clear