Required Technical Specification for 33 V,
XLPE, ICX800 sqmm Copper Core Underground Cable
Where a Manufacturer's Standard or a
national Standard equal to or better than the appropriate specified standard
has been issued and is acceptable to the Purchaser, any material or goods
supplied shall be manufactured. Installed and tested in accordance with the
latest revision of the relevant standard unless otherwise specified.
Where
any Standard referred to in this specification has been superseded by a new
standard prior to the date letter or invitation to tender, the reference shall be
deemed to be to such superseding standard.
Deviations
from this Specification or standards referred to above shall be given in the
bid shall be accepted by the Purchaser before contract placement.
The
goods shall be designed to ensure continuity of service under all working
conditions at the site as the first consideration and to facilitate inspection, maintenance
and repairs. All electrical components shall be adequately rated for their most
onerous duty and the specified ambient temperature.
References Standards for Cable Specification
The
recommendations and tests specified in the standards shall be adhered to. It
shall be the responsibility of the Contractor to demonstrate to the Purchaser
that any proposed Standard is equal to or superior to the equivalent IEC or BS.
All costs for providing such equivalence are deemed included in the Contractors
Tender Prices.
Sponsored:
Climatic Condition
The
offered XLPE U/G cables with jointing Kits must be suitable for working in the
climate conditions of Bangladesh
as described below:
Altitude
Maximum ambient temperature : 0-300 meters above the sea
level
Minimum ambient temperature: 4500C
Humidity: 50C
Mean annual rainfall: 98%
No. of annual rainy days: 1500-3000 mm
Average isokeraunic level: 80-120
days
Pollution of ambient air: dust, salt, chemical
General Technical Requirements
Cross
Link Polyethylene (XLPE) cable shall be suitable for operation at a voltage of
33kV between phases at continuous maximum conductor temperatures of 90 deg. C
the cable shall be suitable in all respect for use on 33kV system nominal three-phase fault level of 25KA.
The
cables and associated fittings, joints and termination shall be so designed to
prevent damage to the cable or fittings, except in the immediate vicinity of
the fault, in the event of an installation failure at any point which results
in a fault current to earth of 25KV for a sec.
Single-core, Copper Conductor, XLPE Insulated Copper screened 800 sqmm. Power Cable
shall comply with IEC 502, except as modified or extended by the requirement of
the specification. The length of cable on a drum shall be 500M continuous or as
specified by the Purchaser and it shall be shipped on standard non-returnable
steel drum, each drum having stencilled on its side; size, type and length of
cable, together with its gross weight, net weight and contract number.
Conductors
All
conductors shall be stranded, circular and compacted and comply with IEC 228.
Copper conductor cables shall be constructed the core of size ICX800 mm2
Conductor Screening
The
conductor shall be screened with an extruded layer of semi-conducting compound,
compatible in all respects with the conductor and insulation materials.
The conductor screen shall be bounded to the insulation such that no voids or discontinuities
are present. The bound shall be adequate to withstand the normal electrical and
mechanical stresses in service without degradation or separation.
Lapped
semi-conducting tape shall not be used for conductor screens.
Insulation
The
insulation shall consist of cross-linked polyethene tightly extruded over the
conductor screen. The insulation shall generally comply with IEC 502.
The
highest possible purity of insulation material is required. The Renderer shall
confirm that adequate precautions are taken to remove contaminants and to
eliminate the introduction of particles of contaminants during the material
handling or extrusion process.
The
Cable shall be manufactured through CCV/VCV.
The
insulation material shall be cross-linked by a dry process. A cross-linking
process of steam curing will not be permitted.
Insulation Thickness
The
thickness of insulation shall be determined by taking the average number of
measurements and shall be not than the tabulated in IEC Publication 502.
Insulation
thickness shall not depart from the specified nominal value by an amount
exceeding the tolerances specified in IEC Publication 502.
The
thickness at any point, however, is less than the specified value, provided the
difference does not exceed 10 per cent plus 0.1mm.
The
thickness of the semi conducting screens on the conductors and over the insulation
shall not be included in the measurement of insulation thickness.
Insulation Screening
The
insulation screen shall comprise a non-metallic semi-conducting polyethylene
part in combination with a metallic part.
The
non-metallic semi-conducting part shall be applied directly upon insulation of
the core and shall comprise a layer of extruded semi-conducting polyethene
compound.
The
conductor screen, insulation and semi-conducting part of the insulation screen
layer shall be applied to the conductor in the common extrusion process with a dry
curing system.
The
metallic part shall be stranded copper applied over the layer of the semiconducting compound.
On a single-core cable, it shall be comprised of a single layer of copper wires
adequately spaced apart.
The
non-metallic part shall be applied directly upon the insulation and shall be a
layer of extruded semi-conducting compound. This screen shall be formed such a
way that it can be readily removed for jointing.
The
insulation screen shall be capable of withstanding a fault current of 25KA for
1 sec. without damage.
Over sheath
The
cable shall be sheathed overall with a MDPE outer sheath. The outer sheath
shall be of smooth and uniform composition and free of holes, cracks, and
bisectors.
As protection against termite attack, the outer covering shall contain the
termite repellent substance of Pb naphthalize.
The
outer sheath shall have adequate strength and thickness to withstand the test
voltage and mechanical tests and be suitable for ambient conditions at the site.
The
outer sheath material shall be capable of withstanding the highest temperature
achieved with the cable at its rated current without damage or deformation at
site ambient conditions.
The
outer surface of the polyethene outer sheath shall be as specified in IEC
502.
Armour
The
amour shall consist of a single layer of non-magnetic wires in accordance with
IEC 502.
The
non-magnetic joints are brazed or welded and any wire shall be not less than
1mm from the nearest joints in any amour wire in the complete cable.
Manufacturer Identification
The
external surface of the cable shall be marked by the following at an interval
of 1000 mm
with 10mm high character throughout the length of the cable:
(i)
33KV,
XLPE, 1-Core, 800sq.mm Cu''
(ii)
"Manufacturers Name"
Continuous Current Rating
The
continuous rating of the cable shall be calculated in accordance with the
procedure described in IEC 287 based on the site ambient condition, with the
insulation parameters as specified. Cable heating due to other cables or other
sources of heat where these can be identified shall be taken into
consideration.
The
maximum conductor temperature shall not exceed 90 deg. C when carrying the
rated current under the most onerous site conditions.
Short Circuit Rating
The
cable shall be capable of withstanding the specified maximum short circuit
current without damage or permanent distortion for the specified times.
The
temperature of the conductor at maximum fault current for the specified time
shall not exceed 250 deg. C as specified in IEC 502.
Type Tests for Cables
The
following type tests shall be made on cables covered in scope of contract by the contractor before the dispatch of cable from the manufacturer’s works if the cables
are already tested it will be at the sole discretion of the purchase whether to
waive the type test or ask for repetition of all or some specific tests. The contractor may quote type test charges for individual tests in his bid for
evaluation purposes.
The following tests shall be included in the type tests Electrical Tests:
a)
Bending
test followed be partial discharge test
b)
Ten
δ measurement
c)
Heating
cycle voltage test followed by partial discharge measurement
d)
Impulse
withstand test followed by a power frequency voltage test
Test on cable components
a)
Check
of cable construction
b)
Resistively
of semi conducting layers
c)
Test
for determining the mechanical properties of insulation before and after
ageing.
d)
Test
for determining the mechanical properties of the non-metallic sheath before and
after ageing.
e)
Ageing
tests on pieces of complete cable to check compatibility of materials
Sponsored:
General Requirement of 33KV, XLPE, 1C x 800 mm² Copper Cable
Item
No.
|
Description
of Items
|
Unit
|
Particulars
|
1
|
Nominal
System Voltage
|
KV
|
33
|
2
|
Maximum
System Voltage
|
KV
|
36
|
3
|
Rated
Voltage (IEC 183)
|
KV
|
18/30(36)
|
4
|
Short
Circuit Current
|
KA
|
25 KA, 3
sec.
|
5
|
Cross-sectional Area of Conductors
|
mm2
|
800
|
6
|
Insulation
thickness
|
mm
|
The average thickness shall not be less than 8.0 mm nominal value as per IEC 502. However,
thickness at any point may be less than the nominal value provided that the
difference does not exceed 0.1mm+10% of the nominal value.
|
7
|
Manufacturing
process
|
|
Manufactured
through CCV/VCV with dry curing.
|
8
|
Conductor
Material
|
|
Copper
|
9
|
Shape of
Conductor
|
|
Compact
Circular
|
10
|
Type of
Conductor Screen
|
|
Semi-conducting
XLPE
|
11
|
Conductor
Temperature at end of short Circuit
|
0C
|
250
|
Indoor Termination Kits for 33KV XLPE, 1C x 800 mm² Copper cable
Item
No.
|
Description
of Items
|
Particulars
|
i)
|
Application
|
For 33KV,
XLPE, ICx800 mm² Copper cable
|
ii)
|
Insulation
|
For Indoor
switchgear terminations
|
iii)
|
System
|
33KV,
effectively earthed system
|
iv)
|
Cable
conductor
|
800 mm²
Copper Conductors
|
v)
|
Kit content
|
-Heat
shrinkable high voltage insulating and non-tracking tubing
-Heat
shrinkable stress control tubing
-Stress-relieving mastic strip
-Truck
resistant sealant tape
-Cable
preparation kit
-Solder
less earth connection kit
-Compression
lugs for 500 mm² Copper Conductors
-Misc.
other material
-Installation
instructions
|
Outdoor Termination Kits for 33KV XLPE, 1C x 800mm² Copper cable
Item
No.
|
Description
of Items
|
Particulars
|
i)
|
Application
|
For 33KV,
XLPE, ICx800 mm² Copper cable
|
ii)
|
Insulation
|
For Outdoor
installation on poles/structures
|
iii)
|
System
|
33KV,
effectively earthed system
|
iv)
|
Cable
conductor
|
800 mm²
Copper Conductors
|
v)
|
Kit content
|
-Heat
shrinkable high voltage insulating and non-tracking tubing
-Heat
shrinkable stress control tubing
-Stress-relieving mastic strip
-Truck
resistant sealant tape
-Heat
shrinkable truck resistant rain shirt
-Support
insulator
-Cable
preparation kit
-Solder
less earth connection kit
-Compression
lugs for 500 mm² Copper Conductors
-Misc.
other material
-Installation
instructions
|
Straight-through joint box for 33KV XLPE, 1C x 800 mm² Copper cable
Item
No.
|
Description
of Items
|
Particulars
|
1
|
Application
|
For 33KV,
XLPE, ICx800 mm² Copper cable
|
Ii
|
Insulation
|
For
underground horizontal mounting
|
Iii
|
System
|
33KV,
effectively earthed system
|
Iv
|
Cable
conductor
|
800 mm²
Copper Conductors
|
V
|
Construction
|
The joint
shall be proof against ingress of moisture and water
|
Vi
|
Kit content
|
-Compression
ferrules
-Valid
filling tape
-Heat
shrinkable stress control tubing
-Truck
resistant sealant tape
-Heat
shrinkable high voltage insulating tape
-Heat
shrinkable black/red dual wall
-Elastomeric
tube
-Roll
spring
-Heat
shrinkable outer jacket tube
-Cable
preparation kit
-Solder
less earth connection kit
-Misc.
other material
-Installation
instructions
|
