Views: 0 Author: Site Editor Publish Time: 2022-11-17 Origin: Site
Power cables are cables used for transmission and distribution of electrical energy, power cables are commonly used in urban underground power grids, power station lead-in lines, industrial and mining enterprises internal power supply and over the river and sea underwater transmission lines.
In the power lines, the proportion of cables is gradually increasing. Power cables are used in the transmission and distribution of high-power electrical power cable products in the main lines of the power system, including 1-500KV and above various voltage levels, a variety of insulation of power cables.
The basic structure of power cable consists of four parts: core (conductor), insulation layer, shield layer and protective layer.
Wire core: The core is the conductive part of the power cable, which is used to transport electrical energy and is the main part of the power cable.
Insulation layer:The insulation layer is the core and the earth and the core of different phases are electrically isolated from each other to ensure the transmission of electrical energy, is an indispensable part of the power cablestructure.
Shielding layer:Power cables of 15KV and above generally have conductor shield layer and insulation shield layer.
Protective layer: The role of the protective layer is to protect the power cable from the intrusion of external impurities and moisture, as well as to prevent direct damage to the power cable by external forces.
Power cables are classified according to the insulation material:
A, oil-impregnated paper insulated power cable: oil-impregnated paper for the insulation of power cables. Its application history is the longest. It is safe and reliable, long service life, low price. The main drawback is that the laying is limited by the drop. Since the development of non-drip dipping paper insulation, to solve the problem of drop restrictions, so that oil-impregnated paper-insulated cables can continue to be widely used.
B, plastic insulated power cable: the insulation layer for the extrusion of plastic power cable. Commonly used plastics are polyvinyl chloride, polyethylene, cross-linked polyethylene. Plastic cable structure is simple, easy to manufacture and process, light weight, easy to lay and install, not subject to laying drop restrictions. Therefore, it is widely used for low-voltage cables, and has the tendency to replace the sticky impregnated oil paper cable. Its biggest drawback is the existence of In the dendritic breakdown phenomenon, which limits its use in higher voltage.
C, rubber insulated power cable: insulation layer for the rubber plus a variety of matching agents, after full mixing and extrusion in the conductive core, after heating vulcanization. It is soft, flexible, suitable for frequent movement, laying bending radius of small occasions.
1 Less land occupation. Generally buried in the soil or laid in the indoor, trench, tunnel, the insulation distance between the lines is small, without towers, occupy less space, basically not occupy the space above.
2 high reliability. Affected by climate conditions and the surrounding environment is small, stable transmission performance, high reliability.
3 with ultra-high voltage, high-capacity development of more favorable conditions, such as low temperature, superconducting power cables.
4 distribution capacitance is large.
5 less maintenance workload.
6 Less possibility of electric shock.