Insulation condition monitoring of epoxy spacers in GIS using a decomposed gas CS2

The epoxy spacers in SF
₆
Gas Insulated Switchgear (GIS) are vulnerable to discharge. Once the surface of the epoxy spacers is deteriorated under discharge, insulation break down may occur subsequently. From a number of experiments carried out on 110 kV GIS, a new gas CS
₂
was detected when creeping discharges occur on the epoxy spacer surface. In order to verify the correlation between CS
₂
and the degradation of epoxy spacers, the quantum chemistry analysis was used to investigate the mechanism of CS
₂
development. Based on the results, the relation between CS
₂
and spacer insulation degradation was determined.