028_2005_xlpe insulated single core underground cables up to 33kv rated voltage

028: 2005 CEB STANDARD

XLPE INSULATED SINGLE CORE UNDERGROUND CABLES UP TO 33kV RATED

VOLTAGE

CEYLON ELECTRICITY BOARD SRI LANKA

Specification

for

XLPE INSULATED SINGLE CORE UNDERGROUND CABLES UP TO 33kV RATED VOLTAGE

CEB Standard 028: 2005 CEYLON ELECTRICITY BOARD No. 50, Sir Chittampalam A. Gardiner Mawatha, Colombo 2 Sri Lanka Telephone: 94-11-2430471, 2421720 Facsimile: 94-11-2430473 E-mail : [email protected]

CONTENTS

Page 1. Scope 1 2. System Parameters 1 3. Service Conditions 1 4. Applicable Standards 1 5. Technical Requirements 2 6. Basic Features 2 7. Manufcture 3 8. Sealing & Drumming 3 9. Quality Control 3 10. Manufacturing Experience 4 11. Performance Guarantee 4

12. Identification & Labelling 4 13. Sample 4 14. Information to be supplied with the offer 4 15. Inspection, Sampling and Testing 5 16 . Routing Test Certificates 6 17 Technical Literature and Drawings 6

CEB STANDARD 028: 2005

SPECIFICATION FOR XLPE INSULATED SINGLE CORE UNDERGROUND CABLES UP

TO 33 KV RATED VOLTAGE

1.0 SCOPE This specification covers the general requirements of the design, manufacture and test of Cross-linked Poly-ethylene (XLPE) Insulated single core underground cables for medium voltage underground systems.

2.0 SYSTEM PARAMETERS (a) Nominal Voltage 33kV 11kV (b) System Highest Voltage 36kV 12kV (c) System Frequency 50 Hz. 50 Hz (d) Method of Earthing Effectively Effectively (e) System fault current & duration 25 kA 20 kA (f) Fault duration 1 s 1 s

3.0 SERVICE CONDITIONS (a) Annual Average Ambient Temperature 30C (b) Maximum Ambient Temperature 40C (c) Maximum relative humidity 90% (d) Environmental conditions Humid tropical climate with polluted

atmosphere (e) Operational altitude From M.S.L. to 1900m above M.S.L. (f) Average ground temperature 30C (g) Depth of laying 1.1m

4.0 APPLICABLE STANDARDS

The items supplied shall be in accordance with the latest editions of the standards specified below and amendments thereof.

(a) IEC 60502- Power cables with extruded insulation and their accessories for rated voltages from 1 kV (Um = 1,2 kV) up to 30 kV (Um = 36 kV)

(b) IEC 60840- Power cables with extruded insulation and their accessories for rated voltages above 30 kV (Um = 36 kV) up to 150 kV (Um = 170 kV)

(c) IEC 60228- Conductors of insulated cables (d) IEC 60540- Test methods for insulations and sheaths of electric cables and cords

(elastomeric and thermoplastics compounds) (e) IEC 60229- Tests on cable over sheaths which have a special protective function and

are applied by extrusion (f) BS 6622 - Cable with extruded cross linked polyethylene for rated voltages from

3800/6600V up to 19/33kV (g) BS 6469 - Insulating and sheathing material of electric cables (h) BS 6360 - Conductors in insulated cables and cords (i) BS 6746 - PVC insulation and sheath of electric cables

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5.0 TECHNICAL REQUIREMENTS (a) Nominal voltage 11kV 33kV (b) Rated voltage (Uo/U) 11/6.35kV 33/19kV (c) Rated fault current (kA/s) 25/1 20/1

6.0 BASIC FEATURES The XLPE Insulated single core underground cables shall have the following characteristics:-

(a) Conductor The resistance of each conductor at 20C shall be in accordance with relevant BS/IEC standard, Circular Compacted Plain Annealed Copper Conductors and of size as stipulated in the Schedule of Prices. (b) Conductor screen Conductor screen shall be of Extruded Semi-conducting Compound type. The extruded layer shall be continuous and shall cover the surface of the conductor completely. The Conductor Screen shall be applied in the same operation as the insulation. The resistivity of the conductor screen shall not be more than 500m at 90 C.

(c) Insulation The insulation shall be XLPE and shall be applied by extrusion and cross-linked to form a compact and homogeneous layer in accordance with the Standards specified. The thickness of insulation shall conform to the relevant BS/IEC standard and compliance shall be checked by the tests given in the relevant IEC standard.

(d) Insulation screen Extruded semi-conducting cross-linked polyethylene (XLPE) in combination with a metallic layer extruded in the same operation as the insulation. The extruded layer shall be continuous and shall cover the surface of the insulation completely. The insulation screen shall be cold strippable.

Note: The conductor screen, the insulation and the non-metallic insulation screen shall be extruded simultaneously in a single-head triple extrusion process.

(e) Inner covering Extruded or lapped materials suitable for the operating temperature of the cable and compatible with the insulating materials. Conditions of cable being buried direct in ground in sustained wet conditions should be considered.

(f) Metallic screen (Applicable only fore 19/33kV rated cables) The core shall be covered with a Copper wire screen. The cross sectional area of the metallic screen shall be able to withstand the specified fault current & duration.

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(g) Longitudinal water barrier Water barrier swelling tape or powder shall be provided to protect against longitudinal water penetration.

(h) Metallic sheath Lead alloy sheath, which shall be free from defects, shall be provided. The thickness of the metallic sheath shall comply with relevant BS/IEC standard.

(i) Oversheath The oversheath shall be of High Density Polyethylene and Black in colour. The mean value of the thickness shall not be less than the specified values and compliance shall be checked by carrying out tests given in the relevant BS/IEC standard.

The over sheath shall withstand the DC voltage test in accordance with relevant BS/IEC standard. This test shall be carried out on each delivery lengths.

(j) Graphite Coating A coating of Graphite shall be applied over the over sheath to carry out D.C. Voltage Test.

7.0 MANUFACTURE Adequate consideration shall have been given in the design of the cable and in the manufacturing process on the following (Documentary evidence shall be supplied along with the tender).

(i) Maximum design electrical stress shall be such that purity of raw materials, manufacturing conditions and ageing of cables have been taken into account. Maximum design stress shall not be more than 5kV/mm.

(ii) Purity of raw materials. (iii) Close control of extrusion process to achieve smooth extruded surfaces, homogeneous

extrudates and prevention of void formations.

8.0 SEALING AND DRUMMING The cables shall be supplied in non - returnable drums. Drums shall be made of steel and suitably protected against corrosion. A polythene lining shall be provided to prevent any damage to cable from the chemical used for preservation of timber.

The drum shall be lagged with closely fitted battens to protect cable from damage. The ends of cables shall be sealed with heat shrinkable caps to prevent the ingress of moisture during transportation and storage. The length of cable per drum shall be 500 metres. The cable length per drum shall not vary more than 2%. 9.0 QUALITY CONTROL ISO 9001 Quality Assurance System shall be followed in the manufacture of XLPE Insulated Underground Cables. Bidders shall furnish documentary evidence (Complete Document) that he has obtained ISO 9001 Certification for the manufacturing plant. Offers of Bidders who fail to furnish the proof of ISO 9001 Certification will be rejected.

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10.0 MANUFACTURING EXPERIENCE The Manufacturer shall have at least ten years of experience in the manufacture of XLPE Insulated Cables and he shall furnish sufficient documentary evidence in the Bid to prove his manufacturing experience.

11.0 PERFORMANCE GUARANTEE Bidders shall furnish five Performance Certificates obtained from Electricity Supply Authorities to whom the Bidder have supplied XLPE Insulated Cables of similar type in the past ten years, three (3) of which shall be from outside the country of Manufacture. The certificate shall indicate the Type, Size, Voltage & Current ratings of the XLPE Insulated Cables, Year of Supply and the Quantity Supplied.

12.0 IDENTIFICATION AND LABELLING The word "CEB", voltage rating as U0/U, size of the cable, manufacturers name or trade mark and travel length shall be embossed at intervals as stipulated in the relevant Standard specified, on the outside of the over sheath. The embossing shall be weatherproof and abrasion proof.

Each drum shall be labelled (with clear stencil) with the following;

(i) PROPERTY OF CEYLON ELECTRICITY BOARD - Tender No. ............. Serial No..............

(ii) Manufacturer's identification. (iii) Cable Type, Voltage Rating, Conductor Size and Number of Cores. (iv) Number and year of standard adopted. (v) Net Weight & Gross Weight in kg. (vi) Length of cable in metre. (vii) Direction of rolling (viii) Year of Manufacture.

13.0 SAMPLE Sample length of about 300mm of each type of cables quoted shall accompany the tender to facilitate analysis and evaluation.

14.0 INFORMATION TO BE SUPPLIED WITH THE OFFER The following shall be furnished with the offer.

14.1 The catalogues indicating the following information on the types and sizes of XLPE Insulated Underground Cables offered. (i) Name of manufacturer and country of origin.

(ii) Catalogue reference number. (iii) Rated Voltage. (Voltage category as per BS 6622) (iv) Standard applicable (v) Nominal cross sectional area. (vi) Number of strands and diameter of strands. (vii) Number of cores. (viii) Conductor material (ix) Conductor screen material (x) Insulation material (xi) Insulation screen material (xii) Maximum Electrical Stress (xiii) Type of bedding (xiv) Type of over sheath.

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(xv) Nominal overall diameter (xvi) Approximate weight of cable/km (xvii) 1) Current rating - laid direct/ducts/air

2) Rating factors and group rating factors add a schedule of particular 3) Maximum symmetrical short circuit current rating curve for 0.2 to 3.0 sec. duration.

(xviii) 1) Maximum conductor resistance at 200C per km 2) Maximum conductor inductance at 200C per km 3) Maximum conductor capacitance at 200C per km

(xix) Maximum allowable conductor temperature at full load and short circuit conditions.

14.2 Type Test Certificates Type Test Certificates conforming to the relevant BS/IEC Standards shall be furnished as listed in the applicable BS/IEC standard, applicable to the voltage category of the cable offered. Type test reports shall be in English language. The Type Test Certificates furnished shall be from a recognized independent testing authority acceptable to the purchaser.

Type Test Certificate, Performance Curves, Tables etc. based on Type Tests shall conform to the relevant Standards specified. The Test Certificate should clearly identify the Items concerned, showing the manufacturers identity, type No. /catalogue No. and basic technical parameters. The Type Test Certificates shall carry an indication of the total number of pages in it (eg. page 1 of 4 etc.) and any incomplete Type Test Certificates or copies with missing pages etc will be rejected.

14.3 Schedule of particular duly filled by the bidder for each type/ rating of cables offered.

14.4 Performance Certificates from five utilities, three of which shall be from utilities outside the country of manufacture.

Quality Assurance Certificate in accordance with ISO 9001.

14.5 A list of Names & Addresses of the purchasers, giving the time of delivery quantities supplied in the past 10 years.

14.6 Drawing indicating all dimensions of cables offered.

14.7 Sample of cable of each type offered in this tender Failure to furnish the above particulars and the sample will result in the offer being rejected.

15.0 INSPECTION AND TESTING

15.1 Inspection The selected Bidder shall make necessary arrangements for inspection by an Engineer appointed by the CEB and to carry out in his presence necessary Sample/Acceptance tests of the cables offered in compliance with the standard specified.

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15.2 Testing (Sample/Acceptance) Tests listed in section 16.0 below shall be witnessed by the Engineer on selected samples. Extra copies of these test certificates shall also be supplied with the cables.

16.0 ROUTING TEST CERTIFICATES The routine test reports/ Factory test reports shall also be supplied with the cables to include following tests.

Following tests shall perform on every completed cable (k) Measurement of electrical resistance of conductors (l) Measurement of electrical resistance of Copper wire screen (m) Power frequency voltage test for 4hrs (n) DC voltage test on over sheath (o) Partial discharge test for 19/33kV rated cables Following tests shall perform on samples selected in agreement with the CEB. The Factory test reports shall be supplied with the cables. (p) Measurement of thickness of insulation (q) Measurement of thickness of non-metallic sheath (r) Measurement of thickness of steel tapes (s) Measurement of diameters of round steel wires and of thickness of flat steel wires (t) Bending test (u) Examination of sheath and protective coverings

(v) Insulation & screening - thickness of individual paper (w) Insulation & screening - tensile strength & elongation at break (x) Hot set test for XLPE insulation & elastomeric sheaths (y) Test of water blocking screen

17.0 TECHNICAL LITERATURE AND DRAWINGS The selected bidder shall supply all relevant drawings, technical literature to facilitate easy installation & faultless operation and catalogues indicating the technical particulars along with the cables.

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ANNEXURE A

PRICE VARIATION

The Bidders shall forward their offers on the basis of the Price Variation stipulated below.

1.0 BASIS OF THE OFFER

(z) Bidders are required to make their offers on the basis of a Base Price (Bo) plus a Fixed Price Margin (FP).

(aa) The Base Price shall be the Cash Seller's Midday Official Average Price of Copper Grade A and Lead, at London Metal Exchange (LME) in US Dollars on the day of the closing of Bids or the previous working day if the day of closing of Bid is a non working day at the LME.

(bb) The Fixed Price Margin shall be quoted in the currency of choice of the Bidder in the case of foreign Bidders and in Sri Lanka Rupees in the case of Local Bidders.

Accordingly FOB Price of foreign Bidders offering cables from outside the country and the ex-factory price of Local Bidders shall be computed as;

[( B X MT x US ) + ( BL x MTL x US ) + ( FP x CC )] x TL Where B - Base Price which is the Cash seller's midday official average price of Copper Grade

A in USD per Metric Ton at the LME on the fixed date (Clause (b) above).

BBL - Base Price which is the Cash seller's midday official average price of Lead in USD per Metric Ton at the LME on the fixed date (Clause (b) above).

FP - Fixed Price Margin per kilometre of Cable in the Currency of choice.

MT - Quantity of Copper Grade A required for the Manufacturer of one kilometre of cable in Metric Ton.

MTL- Quantity of Lead required for the Manufacturer of one kilometre of cable in Metric Ton, as applicable

TL - Total Length of Cable as applicable

CC - Conversion rate from the currency of choice to Sri Lankan Rupees prevailing on the Date of Bid opening.

US - Conversion rate from the US Dollars to Sri Lankan Rupees prevailing on the date of Bid opening.

2.0 AWARD PRICE (cc) The FOB Award Price for Bidders offering Cables from outside the Country and the Ex-

factory Award Price of Local Bidders offering Cables shall be computed as; [( B1 X MT x US ) + ( B1L x MTL x US ) + ( FP x CC )] x TL

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Where B1 - Base Price which is the Cash seller's midday official average price of Copper Grade A in USD per Metric Ton at the first working day immediately after the day of award

B1L - Base Price which is the Cash seller's midday official average price of Lead, in USD per Metric Ton at the first working day immediately after the day of award

(dd) Intimation of the award will be faxed/telexed to the successful Bidder and or his agent in Sri Lanka.

3.0 CONVERSION OF CURRENCY (ee) For the purpose of the evaluation the Price Bo in US Dollars and the Fixed Price Margin

(FP) in the currency of choice of the Bidder will be converted to Sri Lanka Rupees at the official Middle Exchange Rate of the Central Bank of Sri Lanka prevailing on the day of opening of Bids.

(ff) The payment for the supply of Cables outside the country will be made to the Supplier at the contract price in the currency quoted for the Fixed Price Margin (FP). The base price B1 in US Dollars will be converted to the currency of the FP at the exchange rates indicated in the bulletin of the LME applicable on the first working day immediately after the date of the award of the offer; where such exchange rate is not available for the currency of the FP in the Bulletin the official middle exchange rate at the Central Bank of Sri Lanka shall be applicable.

(gg) The payment for supply of Cables from within the Country by Local Suppliers will be made in Sri Lanka Rupees. The Base Prices, B1 & B1L in US Dollars will be converted to Sri Lanka Rupees at the official Middle Exchange rate at the Central Bank of Sri Lanka prevailing on the date of the letter of award.

4.0 VARIATION FIGURES The Bidders shall furnish Fixed Price Margin and the weight of Copper required to manufacture one kilometre of Cables of each type and size as indicated below. Failure to furnish these particulars will result in the offer being rejected.

(hh) Description of the UG Cable offered Voltage Rating U0/U(Um) ...................................................kV .................... - Material of Conductor .................................................... Copper................. - Area of the Conductor ........................................................mm2.................. - (ii) Fixed Price Margin for manufacture of one

Kilometre of Cable in the currency of choice ...................FP..................... - (jj) Weight of Copper Grade A required

for the manufacture of one Kilometre of Cable . ...............kg/km ............... - (kk) Weight of Lead required for the manufacture of one

Kilometre of Cable as applicable ......................................kg/km ............... - ........................................................................................ SEAL AND SIGNATURE OF THE MANUFACTURER DATE.........................

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ANNEXURE B

SCHEDULE OF GUARANTEED PARTICULARS (To be filled by the Bidder for each type/rating)

Failure to furnish complete details will result in the offer being rejected 1. Name of manufacturer and country of origin ........................................ ................................. - 2. Rated Voltage category as per BS 6622 ................................................ kV ........................... - 3. Standard applicable................................................................................ ................................. - 4. Conductor Particulars;

i) Nominal cross sectional area. .................................................... mm........................... - ii) Diameter .................................................................................... mm .......................... - iii) Number of strands. .................................................................... ................................. - iv) Diameter of strands. ................................................................... mm .......................... - v) Material. (Copper) ..................................................................... ................................. - vi) Shape. Round/Shaped ................................................................ ................................. - vii) Type

a) Solid/Stranded ....................................................................... ................................. - b) Compact/Noncompact ........................................................... ................................. -

5. Conductor Screen Particulars i) Material .............................................................................................. Compound/Tape ...... - ii) Thickness. ......................................................................................... mm........................... - iii) Method of Application .................................................................... Lapped/Extruded ..... - iv) Whether applied in the same operation as insulation ....................... Yes/No..................... - 6. Insulation Particulars; i) Material .............................................................................................. ................................. - ii) Extrusion process .............................................................................. Triple or Single........ - a) Minimum average................................................................... mm........................... - b) Minimum at a point ................................................................ mm........................... - 7. Insulation Screen Particulars. i) Type a) Semi-conducting layer............................................................ tape/ extruded .......... - c) Metallic................................................................................... Yes/No..................... - c) Strip ability ............................................................................. Hot/ cold.................. - ii) Material .................................................................................. (Compound/Tape/ Wire)..... -

iii)Maximum Electrical Stress................................................................ ................................. - 8.Inner covering .......................................................................................... Yes/No..................... - 9. Longitudinal water blocking ................................................................... Yes/No..................... -

i) form of water blocking material ........................................................ ................................. - 10. Metallic sheath (Lead) ........................................................................... Yes/No..................... - 11. Oversheath i) Type/Material ..................................................................................... ................................. - ii) Thickness a) Nominal ................................................................................. mm........................... - b) Min. at a point ................................................................mm...........................- iii) Whether Graphite layer provided ..................................................... Yes/No..................... - iv) Whether DC test on oversheath carried out ...................................... Yes/No..................... - 12. Overall diameter of cable ...................................................................... mm........................... - 13. Approximate weight of cable ................................................................ kg/km....................... - 14. Minimum bending radius....................................................................... mm........................... - 15. Whether the cable ends are sealed before shipping ............................... Yes/No..................... - 16. Indicate the details of marking provided on the over sheath. i) Cable Designation .............................................................................. ................................. - ii) Identification of manufacturer........................................................... ................................. - 17. Current Rating; i) Laid direct .......................................................................................... ................................. - ii) Laid in ducts ...................................................................................... ................................. - iii) Laid in air ......................................................................................... ................................. - iv) Whether the maximum symmetrical short circuit current

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rating curves for 0.2 to 3 Sec. duration Furnished............................ Yes/No..................... - Conditions of laying where the above rating are valid.

i) Standard depth of laying..................................................................... ................................. - ii) Standard ground temperature ............................................................ ................................. - iii) Ambient air temperature................................................................... ................................. - iv) Thermal resistivity of soil................................................................. ................................. - 18. i) Maximum conductor DC resistance at 200C ...................................../km........................ - ii) Maximum conductor reactance at 50 Hz.........................................../km ....................... - iii) Maximum conductor capacitance at 50Hz ....................................... F/km ...................... - iv) Coefficient of Thermal variations of the Electrical parameters........ ................................. - 19. Maximum allowable conductor temperature at and duration i) Full Load conditions .......................................................................... 0C / Duration............ - ii) Short Circuit conditions .................................................................... 0C / Duration............ - iii) Over load condition ......................................................................... 0C / Duration............ - iv) Allowable maximum overloading in determining the above............ %/A ......................... - 20. Drum Particulars i) Material. ............................................................................................ (Steel/Wood) ........... - ii) Type of Treatment used for Wooden Drums..................................... ................................. - iii) Dimensions. ..................................................................................... mmxmm .................. - iv) Weight ............................................................................................. kg............................. - v) Standard cable length......................................................................... m.............................. - vi) Weight of standard length with drum ............................................... kg............................. - 21. Whether the Manufacturer has obtained ISO 9001 Certification .......... Yes/No..................... - 22. Whether the entire Type Test Certificates as listed in the relevant

BS/IEC standard are furnished from a recognized Independent Testing Authority................................................................................... Yes/No..................... -

(Please list the type test certificates below) a) .................................................................................................... ................................. - b .................................................................................................... ................................. - c) .................................................................................................... ................................. - d) .................................................................................................... ................................. - e) .................................................................................................... ................................. - f) .................................................................................................... ................................. - g) .................................................................................................... ................................. - h) .................................................................................................... ................................. - i) .................................................................................................... ................................. - j) .................................................................................................... ................................. - k) .................................................................................................... ................................. - l) .................................................................................................... ................................. - m) .................................................................................................... ................................. - n) .................................................................................................... ................................. - o) .................................................................................................... ................................. - p) .................................................................................................... ................................. - q) .................................................................................................... ................................. - r) .................................................................................................... ................................. - s) .................................................................................................... ................................. - t) .................................................................................................... ................................. - u) .................................................................................................... ................................. - v) .................................................................................................... ................................. - w) .................................................................................................... ................................. - x) .................................................................................................... ................................. - 23 Whether the Performance Certificates from three utilities

outside the country of manufacture furnished........................................ Yes/No..................... - I hereby certify the above particulars are true and correct. ........................................................................................ SEAL AND SIGNATURE OF THE MANUFACTURER DATE.........................

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028_2005_xlpe insulated single core underground cables up to 33kv rated voltage

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