The structure of ordinary power cables is different from that of cross-linked polyethylene insulated cables (XLPE), which usually called YJV cable can be manifested in the following aspects:
The difference between cable cross-linking and non-cross-linking in terms of material. The temperature resistance level of non-cross-linked polyvinyl chloride (PVC) cables is generally 70°C, and the cross-linked polyethylene insulated cable is made of cross-linked polyethylene (XLPE) as the insulating medium material, and the temperature resistance can reach 90°C.
Moreover, non-crosslinked polyvinyl chloride will release toxic HCl fumes when burned, and polyvinyl chloride cables cannot be used when fire protection requires low toxicity. For cables with the same conductor cross-sectional area, the carrying capacity of XLPE insulated cables is greater than that of PVC cables.
There are three types of cross-linking methods for cross-linked cables
One is warm water cross-linking (the general voltage level is 0.6/1kV), which is characterized by simple equipment, but the warm water boiling time is generally 7-8h, the production cycle is long, and the material price is cheap.
The second is natural cross-linking, which is characterized by one-time extrusion molding, but the cross-linking process needs to be placed in the environment for 4-8 days, and naturally cross-linked in the air.
The third is radiation cross-linking, which is characterized in that cross-linking needs to be carried out on specific equipment, but the cross-linking process has a short cycle, and large cross-section cables require a relatively large dose of radiation.
Cross-linked polyethylene has the following advantages:
1. Heat resistance: XLPE with net-like three-dimensional structure has very excellent heat resistance. It will not decompose and carbonize below 200°C, the long-term working temperature can reach 90°C, and the thermal life can reach 40 years.
2. Insulation performance: XLPE maintains the original good insulation properties of PE, and the insulation resistance further increases. Its dielectric loss tangent is very small and is not greatly affected by temperature. ?
3. Mechanical properties: Due to the establishment of new chemical bonds between macromolecules, the hardness, stiffness, wear resistance and impact resistance of XLPE are all improved, thus making up for the shortcomings of PE that are susceptible to environmental stress and cracks.
4. Chemical resistance: XLPE has strong acid and alkali resistance and oil resistance, and its combustion products are mainly water and carbon dioxide, which is less harmful to the environment and meets the requirements of modern fire safety.y.
Post time: Jan-07-2023