High Voltage and Extra High Voltage Cables

GUIDE TO THE SELECTION OF EHV AND HV CABLES

EHV and HV cables are specially designed on the basis of the project data. To determine

appropriate design of a high voltage cable for a particular project, the following minimum

information regarding the operating and installation conditions is required:

Installation Data

Length and profile of route (incl. height variations)

Details of laying arrangements (e.g. trefoil or flat arrangement)

Special conditions (e.g. water, heat, cold)

Underground cables;

Method of laying: Direct burial, in ducts or pipes, etc.

Spacing between cables and cable groups

Thermal resistivities and kinds of soil along the route

Depth of laying

Minimum, maximum and average ground temperatures

Cables in air;

Minimum, maximum and average ambient air temperatures

Type of installation (e.g. on racks) and details of arrangement

Details of ventilation (for cables in tunnels)

Whether exposed to direct sunlight

Special conditions, for example fire risk

Other parallel installed power cables, if any: Type and cross-sections of

conductors, carried load & load factor, voltage and layout details.

Data on termination layout details;

Switchgear

Power transformers

Overhead lines (type of conductor, cross-section and length)

Operating Conditions

Nominal voltage of system

Highest voltage of system

Impulse withstand voltage

System frequency

Maximum rated current;

for continuous operation

for cyclic operation (a load curve is essential)

for overload operation, if any (duration is

also essential)

Symmetrical and asymmetrical short-circuit

currents, both between phases and to earth.

Circuit breaker tripping time.

Required screen earthing: At both ends or single

point bonding or cross bonding

Required cable type

Accessories

Terminations (required type)

Joints

Others

Environmental conditions:

The altitude above sea level, if above 1000 m.

Whether excessive atmospheric pollution is

expected

High Voltage Cables

66 kV TO 400 kV COPPER WIRE SCREENED,

COPOLYMER COATED COPPER TAPE SHIELDED CABLES

Typical construction

XLPE insulated, copper wire screened, copolymer coated copper tape shielded,*

HDPE outer sheathed cables with copper or aluminium conductor

Main Properties

Radially and longitudinally watertight

Designed for usage in high fault current

Easy to handle

Lighter and more flexible than lead sheathed cables

Resistant to heavy vibrations

Available in long delivery lenghts to reduce number of joints

Corrosion-free screen area

* Copolymer coated aluminium tape can be applied instead of copolymer coated copper tape on request.

High Voltage Cables

66 kV TO 400 kV COPPER WIRE SCREENED,

LEAD SHEATHED CABLES

Typical construction

XLPE insulated, copper wire screened, lead sheathed, HDPE or PVC outer

sheathed cables with copper or aluminium conductor

Main Properties

Radially and longitudinally watertight

Suitable to carry high fault currents

Suitable for use in hostile environments or underground (at or near water table)

Corrosion and moisture resistant

Resistant to aggressive chemical substances

Offers good protection against rodents

High Voltage Cables

66 kV TO 400 kV LEAD SHEATHED CABLES

Typical construction

XLPE insulated, lead sheathed, HDPE or PVC outer sheathed cables with

copper or aluminium conductor

Main Properties

Radially and longitudinally watertight

Corrosion and moisture resistant

Suitable for use in hostile environments or underground (at or near water table)

Especially suitable for submarine installation

Resistant to aggressive chemical substances

Offers good protection against rodents

Lead sheath acts as a screen

XLPE INSULATED CABLES - TYPICAL CONSTRUCTIONS

Following data are typical values and are given only for information purposes. High voltage cables are

individually designed according to a given application.

Hence, specific values of high voltage cable designs are computed as part of the technical proposal.

TYPE OF CABLE 132 KV

(C u/ XL P E/ Cu-W/

Cu-T/HDPE)

220 KV (Cu / XL P E/ Pb-S/H DPE)

400 KV (Cu/XLPE/Cu-W/

Pb-S/HDPE)

Cross section

mm2

1x630

1x1400

1x2500

Diameter of conductor, approx. mm 30.6 47.2 63.5

Thickness of insulation mm 17 23 28 No.&diameter of copper wires in screen mm 60x1.42 – 86x1.45 Thickness of lead sheath Mm – 2.9 3.2 Thickness of copper tape (Copolymer coated) mm 0.20 – – Overall diameter, approx. mm 88 117 153 Weigh of cable, approx. kg/km 11,000 31,070 52,400 DC resistance of conductor at 20 °C Ω/km <0.0283 <0.0129 <0.0072 AC resistance of conductor at 90 °C:

- In flat formation, separation distance: 2D Ω/km 0.0383 0.0172 0.0108

- In trefoil formation Ω/km 0.0392 0.0178 0.0113_______

Max. permissible conductor temperature ° C 90 90 90

Max. permissible conductor temperature

during short-circuit ° C 250 250 250 Highest system voltage kV 145 245 420 Short duration power frequency

withstand voltage (at 20 °C for 1 minute) kV 275 460 610 Impulse withstand voltage kV 650 1050 1425 Permissible short circuit current

for conductor for 1 second kA 90.0 200.3 357.7 Permissible fault current for metallic sheath/

screen for 1 second kA 14.0 18.7 40.0 Operating capacitance at 20 °C µ F/km 0.18 0.20 0.213 Capacitance current per phase (at 50 Hz) A/km 4.3 8.0 14.7 Partial discharge at 1.5 x Uo pC <5 <5 <5 Dielectric loss factor, tan δ <10x10-4 <10x10-4 <10x10-4 Min. bending radius m 1.8 2.34 3.06 Max. pulling strength

(when pulling from conductor) kN 31.5 70 125 Max. side wall pressure kN/m 5 5 5

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TESTS OF CABLES & ACCESSORIES ACC. TO IEC 62067, IEC 60840

Routine tests of cables

Measurement of electrical resistance of conductor

Partial discharge test (max. 10 pC at 1.5Uo)

High voltage test (at 2.5Uo for 30 minutes)

Electrical test on outer sheaths (this is carried

out when required for a particular project,

depending on the function of the sheath)

Sample tests of cables

Conductor examination and measurement of

electrical resistance

Measurement of thickness of insulation, metallic

and non-metallic sheaths

Measurement of diameters, i f required

Hot set test for XLPE insulation

Measurement of capacitance

Lightning impulse (IEC 62067)

Water penetration test (IEC 62067; depending

on cable design)

Type tests on system; cable & accessories

a. Partial Discharge Test at ambient temperature

(max. 5 pC at 1.5Uo)

b. Tanδ Measurement (Required in IEC 62067)

c. Heating Cycle Voltage Test

d. Partial Discharge Tests

-at ambient temperature (max. 5 pC at 1.5Uo)

-at high temperature (max. 5 pC at 1.5Uo)

e. Impulse Voltage Test followed by a power

frequency voltage test

f. Tests of outer protection for buried joints.

g. Examination of the accesories after completion

of the tests.

Electrical tests after installation

Type test of cables

a. Electrical tests on completed cable:

Bending test followed by partial discharge test

(max. 5pC at 1.5Uo)

Tanδ measurement Heating cycle voltage test followed by partial

discharge measurements

Impulse withstand test followed by a power

frequency voltage test

b. Type tests on cable components:

Check of cable construction

Measurement of volume resistivity of extruded

semi-conducting layers

Tests for determining the mechanical properties

of insulation and non-metallic sheaths

Ageing test on pieces of completed cable to

check compatibility of materials

Loss of mass test on PVC sheaths

Pressure test at high temperature on sheaths

Test on PVC sheaths at low temperature

Heat shock test for XLPE insulation

Carbon black content of PE sheaths

Shrinkage test for XLPE insulation

Test under fire conditions (depending on cable

design)

Water penetration test (depending on cable

design)

Phase checking Measurement of DC resistance of conductor

Capacitance measurement

Measurement of insula tion res is tance

AC High Voltage test

Measurement of s equence impedances

DC Voltage test on outer sheats

In our laboratories, we can perform all necessary

tests of cables upto 400 kV rated voltage according

to IEC, BS, HD, VDE, NEMA, AEIC, ICEA, SS,

NFC, TS, GOST and other world standards and

customers specifications.

CABLE ACCESSORIES & CONTRACTING SERVICES

Cable Accessories

The quality of accessories is as important as the cable itself. Power failures

occur due to mishandling or improper conditions during installation works

as well as incorrect selection of accessories.

Accessories should withstand the operation related dimensional changes and

the working conditions as long as the service life of the cable. This can only

be achieved by proper accessories selection and meticulous attention to the

installation process.

Followings are the most important points to be followed:

Care must be exercised in stripping the semiconductive layer above the insulation without damaging

the insulation.

High degree of cleanliness must be maintained in preparing the insulation layer for jointing and

terminating processes according to instructions.

Insulation and inner semi-conductive materials of the joint must be identical to the material used

in the cable.

To avoid thermal stress during the operation of the cable system, it is highly recommended to use

fixing clamps to attach single core cables to walls, poles or consoles.

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CABLE ACCESSORIES & CONTRACTING SERVICES

Contracting Services

Demirer Kablo provides all the necessary services for the execution

of high voltage cable turnkey projects and partial cable system installations.

Our main services are;

Consulting

Site survey and system design

Most suitable cable design and accessories selection

Project design and engineering

Installation technique determination

Accessories selection & supply

Supply of the necessary equipment, tools and test devices for execution

Civil works

Steel construction works

Cable laying, mounting of accessories

Fault location, site testing

Supervision and commissioning

Training

Maintenance and repair

The most reliable and economical solutions are offered by evaluating the customer's requirements and the local conditions.

Demirer Kablo's Contracting group with its expertise in high voltage cable systems and with its skilled installation team

utilising modern installation, erection and test exuipment is willing to provide the best service to its customers.

400KV PREQUALIFICATION AND TYPE TEST REPORTS

DEM‹RER KABLO TESISLERI SANAYI ve TICARET A.š.

‹stanbul

Bozüyük Ankara

‹zmir

Head Office : Barbaros Bulvar› 49 Preveze Han

34353 Be•ikta• - ‹stanbul / TURKEY

Tel : +90 (212) 261 51 63 Pbx

+90 (212) 227 48 00 Pbx

Telefax : +90 (212) 258 16 56

+90 (212) 261 84 86

Factory : Yaft› Mevkii

Bozüyük / TURKEY

Tel : +90 (228) 314 28 00 Pbx

Telefax : +90 (228) 314 28 08

Contact e.mail addresses :

Export Sales Dept. : export@masscable.com.tr

Local Sales Dept. : satis@masscable.com.tr

Technical Dept. : technical@masscable.com.tr

Purchasing Dept. : purchase@masscable.com.tr

Web site : www.masscable.com.tr