RTV-Coated Insulators
To simulate the field pollutant for laboratory tests, a mixture of 600 g of kaolin, 200 g of CaSO4 , and 5 g of NaCl (commonsalt) per liter of water was made and applied to various types of insulators for clean-fog flashover tests. For these tests, the con-taminant layer was applied to the top, bottom, or entire surface of the insulators [10]. These results showed that when the entire surface of the insulator was coated, the flashover voltage was the highest, whereas coating only the bottom surface resulted in only a slight reduction in the flashover, as illustrated in Figure 2. Su et al. [11] indicated that RTV-coated insulators could op-erate longer than 6 years without preventive maintenance in sub-tropical climates. However, in another study reported by Su et al.