GIS partial discharge severity assessment: A digital image approach

Gas insulated substation (GIS) has been widely used in the field of high voltage power transmission. However, GIS equipments are witnessing more and more internal faults and failures as the voltage class of power network and capacity of power system keep upgrading. Therefore, an effective way in assessing the internal insulation conditions of GIS equipments is needed more urgently than ever. The severity of partial discharge used to be mainly judged through comparing partial discharge spectra on the basis of visual comparison and individual experience, which have served as the most important measurement in the field. Nevertheless, this subjective method falls short of accuracy and efficiency. To better measure the severity of partial discharge in GIS, this paper adopts digital image processing techniques to analyze the correlation between the spectra captured and the severity of partial discharge. Verified by laboratory experiments, the digital image approach demonstrates effectiveness in accurately assessing the GIS partial discharge severity.