Construction of power cables:
1. CONDUCTOR:
·
The main function of the conductor is to carry the transmitted
electrical power
·
The factors affect of choice of the conducting
material:
1- Resistivity. 2- Conductivity.
3-Thermal properties. 4- Mechanical properties.
5-Chemical properties. 6- Oxidation.
7-Corrosion. 8- Soldering problems.
2. INTERNAL SEMICONDUCTOR
LAYER:
· It is thin layer of carbon black
paper.
· The main function of it is to
provide regulation of internal electrical & magnetic fields.
3. INSULATOR:
· The main function of it is to
provide insulation for the cable.
· It is classified into three
main categories:
1-Natural type:
Such as : Fabrics – Rubber – Wood –
Papers.
2- Synthetic materials: ( Polymers)
Such as:
·
Polyethylene ( PE )
·
Cross linked Polyethylene ( XLPE)
·
Polyvinylchloride ( PVC)
·
Polytetra flour ethylene ( PTFE)
·
Polypropylene ( PP)
·
Polyamide
·
Ethylene Polypropylene Rubber
3-Oil –impregnated Paper
4- EXTERNAL
SEMICONDUCTOR LAYER The main function of it to
·
provide regulation of external electrical & magnetic fields
5-METALIC
SHEATH:
·
Materials used for cable sheathing are lead layer, aluminum layer or
copper wire.
·
The main functions of it is to provide:
1-
Good method of cable earthing.
2-
Good path to the fault current.
6-BEDDING (
FILLING ) :
·
It consist of plastics materials which provide:
1-Round cross – section –
area of cables to take largest volume in least space area.
2-Separate the metallic
sheath from the armored layer to prevent galvanic corrosion.
7-ARMOUR:
·
It is a protective non – corrosion layer which provide:
**Gives some protection
against mechanical damage.
8-BEDDING ( FILLING ):
·
It is the same as the previous bedding but provide protection for
external jacket.
9-EXTERNAL JACKET:
·
It is a protective jacket which saves the cable from the surrounding
solid.
·
It could be made of:
1-PVC material.
2-Jute impregnated with
bitumen
