What is XLPE insulated Power Cable?
XLPE power cables are mainly used for the transmission and distribution of electric energy, and are often used in urban underground power grids, power station lead-out lines, internal power supply of industrial and mining enterprises, and underwater transmission lines across rivers and seas.
一、The structure of XLPE insulated Power Cable
The main basic structure of the insulated power cable is composed of four parts: conductor, insulation layer, shielding layer and protective layer.
1. Conductor: The conductor is the main part of the power cable, which plays a conductive role and is used to transmit electric energy. The conductor material is mostly aluminum with strong plasticity and relatively cheap price.
2. Insulation layer: It is to electrically isolate the wire core from the ground and different wire cores to ensure power transmission, and is an indispensable part of the power cable structure.
3. Shielding layer: Since the current of the power cable is relatively large, a magnetic field will be generated around the current, and the shielding layer can play a shielding role in the cable; in addition, the shielding layer can also play a certain role in grounding protection. If it is damaged, the leaked current can flow into the grounding grid along the shielding layer, which plays a role of safety protection.
4. Outer sheath: Located on the outermost layer of the cable, polyvinyl chloride and polyethylene are mostly used for protection and insulation. The environment where cables are laid often has moisture, corrosive substances and termite corrosion. For some cables without metal sheaths, the outer sheath directly protects and seals the main insulation.
5. Steel wire/steel tape armoring: power cables with steel tape armoring are only used for laying directly buried cables or ordinary pipes, ordinary ground, tunnels, etc.; steel wire armoring can withstand general longitudinal tension, so it is suitable for short Distance from overhead laying or vertical, vertical laying.
二、The characteristics of XLPE insulated Power Cable
1. The working temperature is increased from 70°C to 90°C, and the temperature resistance level is obviously better.
2. It has good insulation properties. XLPE maintains the original good insulation properties of PE, and its insulation resistance is further increased. Its dielectric loss tangent value is very small, and it is not greatly affected by temperature.
3. The mechanical properties are enhanced, and new chemical bonds are established during the crosslinking process, which improves the hardness, stiffness, and impact resistance of XLPE, and makes up for the shortcomings of PE that are susceptible to environmental stress and cracks.
4. Chemical resistance, XLPE has strong chemical and oil resistance, and its combustion products are mainly water and carbon dioxide, which is less harmful to the environment and belongs to green environmental protection products.
三、Advantages and disadvantages of XLPE insulated Power Cable
1. Cross-linked polyethylene maintains the original good insulation properties of polyethylene, and the insulation resistance is further increased; its dielectric loss tangent value is very small, and it is not greatly affected by temperature.
2. The cross-linked polyethylene with net-like three-dimensional structure has excellent heat resistance, and it will not decompose and carbonize below 200°C. The heat service time can reach 40 years, and the long-term working temperature can reach 90°C.
3. Xlpe cable 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 protection.
4. Due to the establishment of new chemical bonds between macromolecules, the hardness, stiffness, wear resistance and impact resistance of cross-linked polyethylene are all improved, thus making up for the shortcoming of polyethylene being susceptible to environmental stress and cracking.
Corona resistance and resistance to free discharge are poor, and it is difficult to find the fault point when a fault occurs.