Porcelain insulators are mainly used in HV overhead transmission and distribution lines to insulate and support conductors. Different types of insulators, such as ordinary and pollution-proof types, are selected based on different pollution areas. They are also used in strings according to different voltage levels.

Porcelain insulators include HV suspension porcelain insulators, HV line post porcelain insulators, high-voltage line pin porcelain insulators, and high-voltage porcelain cross-arm insulators, with strengths of 40kN, 70kN, 120kN, 160kN, 210kN, 300kN, 420kN, and 550kN. They are used in strings according to different voltage levels: 35kV uses 3 pieces per string, 110kV uses 7 pieces per string, 220kV uses 14 pieces per string, and 500kV uses 28 pieces per string. For insulator strings of 220kV and above voltage levels, suspension products with a strength grade of 100kN or above are used.

Porcelain insulators have a long history of use in China. They are safe, reliable, and not prone to aging. Their service life is generally over 30 years, and the annual deterioration rate is less than 0.01%.