In China, the manufacture of high-voltage power cable is quite mature and much stable. However, there is a lack of UHV cross-linked cables with higher scientific and technological content, especially for 500kV UHV cross-linked cables.

In the production of this kind of cable, peroxide crosslinking agent should be added to the polyethylene insulating material, and the extrusion of conductor shielding layer, insulating layer and insulating shielding layer should be completed through three-layers co-extrusion; then it is passed through the sealed crosslinking pipe filled with high-temperature and high-pressure nitrogen to complete the crosslinking process continuously and evenly. Selecting nitrogen as the heat transfer medium can make polyethylene to have excellent electrical performance, and the production range can reach 500kV level.

The key point is to use a large amount of high-purity and high flow nitrogen for purging in a short time to obtain better insulation performance.

At present, there are three main ways to supply nitrogen onsite in industry - low temperature distillation separation method, molecular sieve pressure swing adsorption (PSA) method and electrolysis method. After decades’ development, the pressure swing adsorption process of (PSA) technology is very mature. It has been widely used in chemical industry, metallurgy, electronics, food and other fields that requires inert gas protection, replacement and suppression. With advanced technology and high degree of automation, the process can not only solve the problem of self- production and self-supply of nitrogen, but also meet the gas production demand in cross-linked cable production line for high purity and high flow of nitrogen; At the same time, molecular sieve pressure swing adsorption (PSA) nitrogen generator has the characteristics of low investment one-time, low cost and high degree of automation, so it is favored deeply by enterprises with small and medium-sized nitrogen demand.