Technology And Applications Of Cold-shrinkable Power Cable Accessories

Power cable accessories refer to the intermediate connections and terminal connectors of various cables in a cable line.  They, together with the cables, constitute the power transmission network. Cable accessories are primarily designed based on the characteristics of the cable structure, ensuring and restoring the cable's performance while guaranteeing the extension of the cable length and the connection of the terminals. According to their use, they are generally divided into terminal connectors and intermediate connections. Terminal connectors are further divided into indoor, outdoor, and equipment terminals. There are many types of cable accessories, and the common ones are listed below. Each type has its own characteristics and limitations, and no single technology can completely replace another. ① Wrap-around cable accessories; ② Heat-shrinkable cable accessories; ③Cold Shrink Cable Accessories; ④ Pre-fabricated assembly type cable accessories; ⑤ Pre-fabricated insertable cable accessories (also known as insertable separable connectors); ⑥ Resin-cast cable accessories; ⑦ Molded cable joints; ⑧ Porcelain sleeve terminals. Currently, the commonly used cable accessories are mainly heat-shrinkable cable accessories (heat-shrink type), cold-shrinkable cable accessories (cold-shrink type), and pre-fabricated assembly type cable accessories (pre-fabricated type, see Table 1).
In the early 1970s, 3M Company in the United States invented cold-shrink technology and applied it to cross-linked cable accessories in situations where open flames could not be used (mines, chemical plants), opening a new era for the application of cold-shrink cable accessories. In 1993, a company was established in Shanghai to produce and sell cold-shrink cable accessories. Around 2000, domestic manufacturers such as Changsha in Hunan, Wanma in Zhejiang, and Changyuan in Shenzhen successively developed and produced similar products.  Because of their ease of use, speed, and safe and reliable operation, these products were widely welcomed by users. They became a major force in the cable accessories industry, alongside heat-shrinkable and pre-fabricated types, and quickly established a dominant position in the 10-35kV cross-linked cable accessories application field. In late February 2004, cold-shrinkable power cable accessories were installed on China's first 35kV superconducting cable, the world's (USA, Denmark) third 35kV superconducting cable, which was put into operation at the Puji Substation in Kunming City, Yunnan Province. This was another classic achievement in the power industry, opening a new chapter in China's power transmission field.