Performance of nonceramic insulators under tropical field conditions

This paper presents the results of investigations on the performance of non ceramic insulators in tropical held conditions. Six different types of 33 k V insulators (silicone rubber, EPDM composite, porcelain, and RTV coated po rcelain) were installed at six different test sites exposed to marine, indu strial, and clean environments in Sri Lanka and Tanzania. The visual scruti ny, hydrophobicity class (HC) and surface conductivity were used for the ev aluation of the field performance. The silicone rubber and RTV coated insul ators preserved the hydrophobic properties although some biological growth was found on them. The EPDM insulators showed distinct surface changes. At the same time, damage due to dry-band arcing appeared on the porcelain insu lators exposed to marine pollution.