Selecting Optimal Outdoor Insulation Under Heavily Polluted Conditions
by Shakir Hafeez

The EHV transmission network in Pakistan faces exceptionally harsh service conditions and frequent pollution flashovers. In addition, due a long coastline and heavy industry, there is severe onset of corrosion affecting both towers and galvanized cap & pin insulators. This presentation describes countermeasures based on application of a silicone rubber coating to existing fog type insulators to prevent these problems and as an alternative to costly yet ineffective live line washing. It will also discuss implementation of a new CIGRE technical approach to select the most suitable insulator type and profile as well as coating formulation by setting up Naturally Polluted Insulator Pilot Testing Stations in Lahore and elsewhere.