Cross-linked cable is the abbreviation of cross-linked polyethylene insulated cable. It is composed of conductor, insulating material, internal and external semi-conductive material, sheath material, shielded copper tape, armored steel tape/steel wire, inner lining, isolation sleeve, filling material, etc. Part of the cable. Different components have their own usage requirements and characteristics. For example, XLPE insulated cables are the insulating medium material of XLPE, and the temperature resistance can reach 90°C. Therefore, the XLPE insulated cables cannot Compared with the advantages, it has simple structure, light weight, good heat resistance, strong load capacity, non-melting, chemical resistance, and high mechanical strength. It is mostly used in power transmission and distribution lines with power frequency AC voltage of 500KV and below.
In order to improve the temperature resistance of polyethylene, chemical or physical methods are usually used to make it into a body-shaped molecular structure. This is called cross-linking, which is the basic principle of cross-linking. So, do you know what is the degree of cross-linking of cross-linked cables? The following is an introduction to the factors that affect the degree of cross-linking of cross-linked cables for your reference.
1. Temperature
The temperature here not only refers to the working temperature of the cross-linked cable during cross-linking, but also includes the extrusion temperature. Specifically, it is:
(1) The cross-linking process is completed in the heating section of the vulcanized tube. Therefore, when other factors remain unchanged, the higher the temperature of the vulcanized tube, the higher the degree of cross-linking of the cross-linked cable. This is a certain point. Generally speaking, considering various factors, the temperature of the vulcanized tube for dry cross-linking should be around 290~310℃, otherwise the cross-linking degree of the cross-linked cable during cross-linking will be affected and will be greatly changed. Small, it is not a good thing for the use of cross-linked cables.
(2) Extrusion temperature. Because the cross-linked cable is processed, an extruder is required. If the cross-linking degree of the cross-linked cable is suitable, it is necessary to use a suitable extrusion temperature during the processing of the extruder, and the extrusion temperature may be related to the formula of the raw material, so this requires The material is fully plasticized without pre-crosslinking.
2. Linear speed during crosslinking
Obviously, the higher the line speed, the higher the production efficiency, but the degree of crosslinking will be lower. Therefore, when crosslinking, the line speed should be suitable. The line speed will be affected by factors such as rated voltage, cable specifications, cooling water temperature and water level, vulcanizing tube, etc. The larger the cable cross section, the greater the amount of glue required from the extruder, so the line speed cannot be too fast; The higher the temperature and the longer the pipeline, the faster the line speed; the higher the voltage, the thicker the insulation and the slower the crosslinking speed…
Well, the above is an introduction to the factors that affect the degree of cross-linking of cross-linked cables. I hope everyone can understand, and then cross-link correctly according to actual conditions and requirements.
