End-of-Life Evaluation of RTV Coated Porcelain and Glass Insulators under Pollution Conditions

Ageing of Room Temperature Vulcanising (RTV) silicone rubber coated porcelain and glass disc insulators are reported under combined voltage stress and salt-fog conditions till the loss of hydrophobic properties of RTV coating in an ageing chamber. The electrical characteristics are obtained by online monitoring of leakage current and material characteristics are analysed by Energy Dispersive X-Ray (EDX) analysis. RTV coated glass insulators shattered into pieces after 2600 hours of ageing while RTV coated porcelain after ageing for 4600 hours lost its hydrophobic properties and started behaving like a normal un-coated porcelain disc insulator.