HV Insulator Protection
CharCoat IC is a unique room temperature vulcanized (rtv) silicone elastomer formulation specifically developed for the prevention of pollution flashover of high voltage outdoor insulation. The exceptional hydrophobicity of CharCoat IC inhibits the formation of continuous moist conductive layers on insulator surfaces. This, in turn, limits the flow of leakage currents thus preventing the creation of dry bands and partial discharges – critical steps in the flashover process.
CharCoat IC involves a two-part material application process, where a small volume of IC catalyst is mixed into the coating before use. Unlike materials that use an oxime cross-linking agent, CharCoat IC’s curing system offers several advantages: it does not require atmospheric moisture for vulcanization, the cure rate is unaffected by humidity, no by-products are released during curing, and shrinkage is minimal (<0.1% compared to 0.5% to 1% for oxime systems). Additionally, its shelf life is significantly longer than that of single-part rubbers.
Although the coating can adhere to porcelain and glass to some extent, it is recommended to use CharCoat IC Primer, which comes with all purchased coatings, to ensure a strong and permanent bond to ceramic, glass, and resin materials. If a separate primer is not used, a bonding agent must be included in the coating itself, which reduces the silicone content and negatively impacts the material’s performance and longevity. Therefore, it is strongly recommended to apply the primer only at the interface between the insulator and the coating, leaving the rubber layer free from unnecessary materials.
Application on Insulator
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