Preformed fittings were invented by PLP Corporation in the United States in the 1940s and have been successfully applied in many high-voltage lines abroad for decades. In my country, preformed fittings began to be used in the 1980s, mainly in all-dielectric self-supporting optical fiber cables (ADSS), optical fiber composite overhead ground wires (OPGW), and ultra-high-voltage transmission line projects.
In the areas served by the power grid, preformed fittings began to be used on overhead conductors after the 2008 Southern China ice storm. Extensive data from overhead line operations show that preformed fittings offer superior performance compared to traditional fittings, including stress dispersion, tool-free installation, long service life, and low fitting loss. Although the production cost of preformed fittings is slightly higher than that of traditional power fittings, in the long run, using preformed fittings can significantly reduce the operating costs of the lines.
