Performance of RTV silicone rubber coatings installed in coastal systems

RTV SIR coatings can improve the performance of ceramic insulators, in cases where pollution problems are experienced and the use of composite housings is not technically or financially in profit for the electrical utility. In this paper the performance of coatings installed in a coastal high voltage substation is investigated by measurements of leakage current. The measurements indicated the importance of the wetting mechanism, for the specific environmental conditions. In the case of condensation the surface activity on the coated insulators has been remarkably suppressed. On the other hand, in the case of light rain the same levels of activity have been recorded for both coated and non-coated insulators. The overall performance of the coated insulators, for the specific conditions, is superior in comparison to the non-coated insulators.