|
1
|
Higher
current ratings : It is possible to use one lower size
of cable as compared to PVC. |
|
2
|
Higher
emergence overload withstand capacity. It can withstand
overload temperature up kto 130'C because of better
ageing properties and resistance to deformation under
load. |
|
3
|
Higher
short circuit rating : XLPE can withstand short circuit
temperatures up to 250'C whereas PVC cables can only
withstand up to 160'C. |
|
4
|
Enhanced
life because dielectric losses are very small. |
|
5
|
Jointing
and terminations are very easy. |
|
6
|
XLPE
cables are not prone to fatigue damage due to vibrations
or loading cycles. |
|
7
|
Easy
handling during installation because these cable are
lighter in weight. |
|
8
|
XLPE
cable retain their flexibility down up to 40'C. |
|
9
|
No
elevation limit. |
|
10
|
Better
resistance to most chemicals such as ordinary acids,
bases and oils. |
|
11
|
PVC
cables have distinct disadvantages regarding encironmental
protection, if they burn they gives of corrosive gases.
Although XLPE also burns but the combustion products,
carbon dioxide and water, do not cause a damage. Moroverm
it does not melt like polyethylene. |
General
Construction
XLPE Cable are manufactured confirming to IS ; 7098 or as
per customers requirement.
Conductor
The conductor of power cables is generally made from EC
grade aluminium and annealed high conductivity copper is
used for control cables. All cinductors confirm to IS :8130.
Power Cables with copper conductor can also be supplied
as per customer's requirment. The conductor are solid/ stranded/bunched
as per the requirement.
Insulation
The consuctor is insulated with the XLPE compound by extrusion.
|
Properties
|
XLPE
|
PVC
|
| Normal
Continuous Operation temp. ('C) |
90
|
70/85
|
| Emergency
Overload temp. ('C) |
130
|
95/105
|
| Short
Circuit temp. ('C) |
250
|
160
|
| Chemical
Resistance |
Very
good
|
Very
good
|
| Moisture
Resistance |
Very
good
|
Very
good
|
| Fire
Resistance |
Good
|
Very
good
|
| Min.
Installation ('C) |
-40
|
0
|
| Thermal
Resistivity of Dielectric ('C cm/Watt) |
350
|
600
|
| Volume
Resistivity of Dielectric (Ohm-cm) |
10/17
|
10/13
|
| Dielectric
Constant |
2.3
|
6
|
| Break
down volatge (Kv/mm) |
40
|
20
|
| Power
factor at 50MhzHz |
0.0008
|
0.1
|
Inner
Sheath
The laid up cores are provided
with the PVC inner sheath either by extrusion or by wrapping
of plastic or proofed tapes. Single core cables do not hae
inner sheath.
Armouring
Armouring is applied over inner sheath in case of multicore
cables and over insulation in case of single core cables.
In case the calculated diameter soesnot exceed 13mm, the
armour consists of galvanized roound steel wires. Where
the calculated diameter under the armour is greater than
13mm the armour generally consits of flat steel. If required
the cable can be manufactured wth round steel wire calculated
diameter of cable exceeds 13mm.
Outer
Sheath
Outer sheath is applied by the required PVC comppound by
extrusion over insulation in case of unarmoured single core
cables, over inner sheath in case of unarmoured multicore
cables & over armouring in case of armoured cables.
Routine
Test
Tests carried out on each cables to check the requirement
which are likely to vary during production.
1. Consuctor Resistance
2. High Voltage.
3. Armour Resistance (for mining Cables)
|
For
identification of cores the following colour scheme
is adopted.
|
|
Single
Core
|
Red,
Black, Yellow, Blue or Natural
|
|
Two
Core
|
Red
& Black.
|
|
Three
Core
|
Red,
Yellow & Blue
|
|
Four
Core
|
Red,
Yellow, Blue & Black.
|
|
Five
Core
|
Red,
Yellow, Blue, Black & Grey.
|
|
Six
Cores and above
|
Two adjacent cores ( counting & direction core)
in each layer. Blue & Yellow, remaining cores
are Grey.
|
| |
By
printing nos. In numerals on the outer surface ot
the core as per CI 10.3 of IS:7098 (Part-1)
|
|
