Cross-linked cable usually refers to the use of cross-linked materials for the insulation of the cable, and the most commonly used material is cross-linked polyethylene (XLPE).

The process is to use a polyethylene (PE) material with a linear molecular structure through a specific processing method to form a cross-linked polyethylene with a three-dimensional network branch structure. The long-term allowable operating temperature is increased from 70°C to 90°C (or higher), and the short-circuit allowable temperature is increased from 140°C to 250°C (or higher). While maintaining its original excellent electrical performance, it has greatly improved Actual performance.

Cable accessories are widely used because they solve the cable tapping problem in the overhead line conversion cable, and are fully insulated, fully sealed, maintenance-free, and flexible in installation and combination. Cross-linked cables are most commonly used in 10kV distribution networks. The cable accessories used by Xiangying refer to the terminal head and the middle head, as well as the cable distribution box. The oil-paper insulated cable terminal head traditionally used in the early days is now rarely used. Now the most commonly used are heat-shrinkable cable heads and cold-shrinkable cable heads and cold-shrinkable middle heads. Among them, cold-shrinkable cable heads and cold-shrinkable middle heads are also called prefabricated cable accessories. In the distribution network cable, the cable distribution box is widely used. application. The prefabricated cable accessories are also fully insulated, fully sealed, and fully shielded, suitable for various harsh environments, reliably ensuring equipment and personal safety, and greatly improving the reliability of power supply, so they are the future development direction.　

Cross-linked polyethylene (XLPE) insulated power cables (hereinafter referred to as cross-linked cables) will produce dendritic discharge channels under the action of electric field and water. This phenomenon is called water treeing. Water trees will continue to grow over time, eventually leading to insulation breakdown and becoming an important cause of early damage to power cables.

The production and application of ordinary cross-linked cables have a history of nearly 30 years. They have excellent electrical and mechanical properties in dry environments. However, in actual applications, the environment for cable laying is usually harsh, and cables often require short-term or long-term Soaked in water, or in an environment with high humidity, and ordinary cross-linked cables have no water tree resistance at all. After long-term use, the insulation will gradually absorb the moisture in the environment, and there are a large number of small in the cable insulation. Therefore, the micropores are filled with water, and the water-filled micropores can produce water trees at a very low voltage. Under the long-term action of the electric field, a large number of water branches will be induced in the cable insulation layer, and the aging of the water trees will cause the insulation molecules to crack; when the water trees in the micropores reach a saturated state, the electrical and mechanical properties of the insulation will drop sharply, and the conductive water branches (Electrical tree) will lose a lot of electric energy, and finally cause the breakdown of the cable insulation layer, thereby greatly reducing the cable life.