AC performance of silicone and glass barriers in clean and polluted atmosphere

• A comparative study of silicone rubber and glass insulating barriers performance was done.
• The dielectric properties of the insulating barriers were measured using the Schering bridge.
• We quantify the performance of two types of insulating barriers in clean and polluted atmosphere.
• Laboratory observations of the discharge have been carried out using a video camera system.
• The results argue well for the use of silicone insulation as a screen in the system air gap.

The aim of this article consists in the comparative study of silicone rubber and glass insulating barriers performance. The study is carried out under AC voltage in a clean and polluted atmosphere. Their dielectric properties needed to characterize their performance were measured using the Schering bridge. The effect of the grounded electrode's sizes and their isolation in the point–plane air gap system on the optimization of the insulating barrier performance was analyzed. Moreover we present findings of experiments which allow quantifying the effects of the clean or polluted atmosphere, the degree of contamination, the number of polluted faces of the barrier as well as the electrode axis orientation of the rod–plane system on their protection reliability.Finally, this investigation has been supported by laboratory observations of the discharge phenomena in the air gap from inception to full flashover in all cases using a video camera system. The results from this study argue well for the use of silicone insulation as a barrier in non-uniform field electrode systems regardless of the nature of the environment in which it must operate.