cable news: basic structure and classification of power cable
from：guichao author：admin click： 205 addtime：2017-03-06 10:06:26
basic structure
the basic structure of the power cable is composed of four parts: the wire core (conductor), the insulation layer, the shielding layer and the protective layer.
(1) wire core
the core of the power cable is used to transmit electricity, which is the main part of the power cable.
(2) insulating layer
insulation layer is the core of the wire and the earth and the different phase of the core of the electrical isolation from each other, to ensure the transmission of electricity, power cable is an integral part of the structure.
(3) shielding layer
15kv and above power cables are generally shielded conductor and insulation layer.
(4) protective layer
the function of the protective layer is to protect the power cable from the invasion of the external impurities and moisture, and to prevent the external force from damaging the power cable directly.
classification:
according to the voltage level:
according to the voltage level can be divided into medium and low voltage power cable (35 thousand volts and below), high voltage cables (more than 110 thousand volts), ultra high voltage cables (from 275 to 800 thousand volts) and ultra-high voltage cables (above 1 million volts). in addition, the current system can be divided into ac and dc cables.
according to the insulation material:
1, oil impregnated paper insulated power cables with oil paper insulated power cable. the longest history of its application. the utility model has the advantages of safety, reliability, long service life and low cost. the main disadvantage is the laying of the drop limit. since the development of insulation paper after dripping tidewater dip solution, drop restrictions, so that the oil paper insulated cable continued widely used.
2, plastic insulated power cable insulation layer is extruded plastic power cable. polyvinyl chloride, polyethylene and crosslinked polyethylene. the utility model has the advantages of simple structure, convenient manufacture and processing, light weight, convenient installation and installation, and is not limited by laying gap. it is widely used for medium voltage cables, and replace the sticky impregnated oil paper cable. the biggest drawback is that there is a breakdown of the tree, which limits its use at higher voltages.
3, rubber insulated power cable insulation layer for rubber with a variety of complexing agent, after a full mixing after the pack in the conductive wire core, after heating vulcanization. the utility model has the advantages of softness and elasticity, and is suitable for occasions with frequent movement and small bending radius.
used as a natural rubber compound insulation - sbr mixtures, ethylene propylene rubber, butyl rubber etc..