Protective Coatings for Porcelain Insulators

This review presents a selection of patents reported on coatings for high-voltage porcelain insulators. An insulator is subject to surface corrosion due to air pollution or salt deposition, which may form a conductive electrolytic solution. This may cause a flashover and shut down the transmission and distribution electrical energy line, particularly in high polluted or coastal regions. The main goal of protective coatings has been to produce flashover-free high-voltage insulators. Coating porcelain insulators with specific inorganic or organic may prevent the leakage current. Major approaches are based either on semiconducting glazes or hydrophobic coatings.