In China, three-phase three-wire system is adopted for HVDC transmission, so it is three-wire system. HVDC transmission adopts two-phase system, so it is two-wire system. The three wires are three-phase electricity from step-up transformer.
the current fire-retardant cable for coal mines (using chlorine-containing polymers as the sheath material), once burned by heat, emits a very large amount of smoke.
The insulating material of the cross-linked cable is XLPE, the base material of which is PE and the like, and the cross-linking process is formed by forming a linear mesh-structured polyethylene (PE) material through a specific processing method to form a bulk-type mesh-shaped branch structure.
In the case of laying power cables along marshes or water, the whole power cable capable of withstanding tensile force should be selected. When passing through a small stream, a power cable with armor (used outside the armor) should be used.
The wire is used to carry a current conducting metal wire. There are various forms such as solid, stranded or foil braided. According to the insulation condition, it is divided into two categories: bare wire and insulated wire.
Pure conductor metal, no insulation and sheath layer, such as steel core aluminum stranded wire, copper-aluminum busbar, electric locomotive line, etc.
When the power cable passes a certain load current, it always exceeds or exceeds the maximum continuous working temperature allowed by the cable (the cross-linked polyethylene insulated cable allows 90 °C). The cable will heat for a long time.
In the power engineering installation, the cable termination head and the intermediate cable connector are important electrical equipment components in the transmission and transformation cable line.
