Evaluation of the Performance of Polymer Coatings for Electrical Insulators in a Highly Air-Polluted Environment

چکیده مقاله

Electrical insulators have the function of supporting the electrical power cables and insulating conductors. The most economical types are ceramic and glass insulators, which have low efficiency due to electrical discharge in humid and polluted areas. Today, lightweight concrete-polymer composite insulators with easy installation have replaced the older generation of insulators, offering high efficiency in areas with polluted and humid air. Polymeric materials including silicone rubber, ethylene propylene diene monomer (EPDM), polyurethane, acrylic, polyester, and epoxy resins have been considered to create self-cleaning and hydrophobic surfaces that can be applied to electrical insulators. In this article, the application of polymer coatings on high-voltage electrical insulators in air-polluted environments to enhance insulation performance and reduce transmission line failures has been reviewed. Reports show that silicone rubber has the highest efficiency for the external insulation of power transmission systems, and its chemical structure, types, and hydrophobicity, as well as its chemical, physical, and mechanical properties have been discussed. Furthermore, the effects of applying micro, nano, and mixture of micro-nano fillers (including inorganic oxides such as silica (SiO₂), zinc oxide (ZnO), and titanium dioxide (TiO₂), and organic fillers) and their concentrations on the electrical properties, weathering resistance, and mechanical strength of polymer coatings applied to insulators were reported. Also, various methods for hydrophobizing surfaces have been described. It was shown that silicone rubber-EPDM coatings containing modified silica nanoparticles, aluminum trihydroxide, silicone oil, UV stabilizers, pigments, and fillers have the highest hydrophobicity (water droplet contact angle of 161°) and self-cleaning properties. These coatings can be effectively applied to high-voltage insulators without the need for continuous washing.