TECHNICAL SPECIFICATION FOR 22 KV XLPE POWER CABLE (CROSS LINKED POLYETHELENE CABLE)

Transcription

1 TECHNICAL SPECIFICATION FOR 22 KV XLPE POWER CABLE (CROSS LINKED POLYETHELENE CABLE) [1] SCOPE: This Section of the Specification covers design, manufacturing, testing, packing, supply & delivery of 22 KV XLPE Dry/Gas cured insulated power cable for effectively earthed specification system. [2] STANDARDS: Unless otherwise specified, the cable shall conform in all respect to IS: 7098 (Part-II)-1985 with latest amendment thereof. [3]CLIMATIC CONDITIONS: The climatic conditions under which the cables shall operate satisfactorily are as follows: 3.1 Maximum ambient temperature of air 50º C 3.2 Minimum ambient temperature of air in shade 4º C 3.3 Maximum daily average ambient temperature 40º C 3.4 Maximum yearly average ambient temperature 30º C 3.5 Maximum relative humidity 95 % 3.6 Average number of thunder storm days per annum Average annual rainfall 150 cm 3.8 Maximum wind pressure 150 kg/cm Altitudes not exceeding above MSL 1000 mtrs 3.10 Maximum soil temperature at cable depth 30º C 3.11 Maximum soil thermal resistivity [4] PRINCIPAL PARAMETERS: 150ºC - cm/watt 22 KV (E) Grade XLPE, 3-Core, power cable shall be of high conductivity, stranded compacted, HD aluminum circular shaped conductor with XLPE (cross linked Polyethylene) Dry/Gas cured insulation provided with shielding of extruded semi-conducting materials over conductor and XLPE insulation. Each insulated core shall have copper tape screen, laid together and provided with common covering of PVC Inner Sheath (Extruded). Overall galvanized steel strip armour and PVC outer sheath shall be provided. The specification for manufacture of cable shall be conforming to IS: 7098 (Part-II) 1985 (latest edition) for 22KV (E), 3-phase, 50 Hz. Earthed systems. DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 1 /13

2 Outer sheath shall be designed to afford high degree of mechanical protection and shall also be heat, oil, chemical and weather resistant, Common acid, alkalis and sealing solution shall not have adverse effect on material of PVC sheath. Cable shall be suitable for laying in covered trenches and / or buried under-ground in outdoor. [5] CABLE PARAMETERS: a Voltage grade (Uo / U) 12.7 / 22KV b Cores (Nos) 3 nos c Nominal system voltage 22 KV d Highest system voltage 24 KV e System frequency 50 HZ f Variation in frequency + 3% g Maximum allowable temp of conductor during continuous normal operation at rated full load current. 90º C h Maximum allowable temp. under short circuit condition 250º C i 1.2/50 micro sec lightning impulse withstand voltage value 125KVp j 5 Min, Power frequency withstand voltage ( KV rms) 32KV k System earthling -Shall be effectively earthed [6] GENERAL TECHNICAL REQUIREMENTS: 6.1 ALUMINIUM CONDUCTOR: The cable conductor shall be made from high conductivity stranded High Density aluminum to form compacted circular shaped conductor having resistance within limits specified in IS: 8130/1984 and any latest amendment to it. 6.2 CONDUCTOR SHIELD: The conductor having semi-conducing screen shall ensure perfectly smooth profile & avoid concentration of stress. The conductor screen shall be extruded in the same operation as the insulation. The semi-conducting polymer shall be cross linked. 6.3 XLPE INSULATION: The XLPE insulation shall be suitable for 22 KV system voltage and should be manufactured with Dry/Gas curing process. The bidder shall submit the description of Dry/Gas curing process, with the clear inclusion of equipments / parameters involved. The manufacturing process shall DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 2 /13

3 ensure that the insulation shall be free of voids. The insulation shall withstand mechanical and thermal stress under steady state and transient operating conditions. The extrusion method should give very smooth interface between semi-conducting screen and insulation. The insulation of the cable shall be of high standard quality generally conforming to IS: 7098 (Part II) 1985 and any latest amendment to it. 6.4 INSULATION SHIELD: Non-metallic semi-conducting shield shall be provided over the insulation to confine electrical field to the insulation. The insulation shield shall be extruded in the same operation as the conductor shield and the insulation by suitable extrusion process. The XLPE insulation shield shall be of tended type. The copper metallic overlapped tape shield shall be provided. 6.5 FILLER AND INNER-SHEATH: The sheath shall be suitable to withstand the site conditions and the desired temperature. It shall be of consistent quality and free from all defects. The PVC sheath shall be extruded. The material of fillers and inner-sheath shall be compatible with the temperature ratings of the cable and shall have no deleterious effect on any other component of the cable. Central filler shall also, be provided with other peripheral fillers to have proper circular section. 6.6 ARMOURING: Armouring of galvanized steel strip shall be provided. The dimensions of steel strips shall be as per latest edition of IS: OUTER-SHEATH: Extruded type ST-2 PVC outer-sheath, conforming to IS: 5831-(1984) (latest edition) over armouring with suitable additives (to prevent attack by rodents & termites), shall be provided. 6.8 CONSTRUCTION: The cable shall have suitable fillers laid up with insulation cores to have subsequently circular cross-section before the inner sheath is applied. The fillers shall be suitable for operating temperature of the cable All materials used in manufacturing of cable shall be new, unused and of finest quality. All materials should comply with the requirements / tests as per applicable IS / IEC specification, Indian Electricity Rules and any other statutory provision of rules & regulations The PVC material used in the manufacture of cable shall be of reputed manufacturer. No use of recycled PVC is permitted. The purchaser reserves the right to ask for documentary evidence of the purchase of DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 3 /13

4 various materials, (to be used for the manufacture of cable) as per checking of quality control. Quality Assurance plans shall be submitted. 6.9 CURRENT RATING: The indicative values of continuous current carrying capacities at Maximum conductor temperature of 90 C (for design purpose by field) of the various sizes of the cables are given below: Sr. No. Size of 3 Core XLPE Cable Continuous current carrying capacity in Amps.(For 11/22 KV XLPE cable) in Ground in air 1 3C x 185mm 2 size Short circuit ratings of various sizes of 3 core cable calculated for duration of one second at maximum temperature of 250 C, are given below: Sr. Size of 3 Core Conductor short circuit rating No. XLPE Cable in ka (rms)(for 11/22 KV XLPE cable) 1 3C x 185mm 2 size ka The current rating shall be based on maximum conductor temperature of 90º C with ambient site condition specified for continuous operation at the rated current. [7] OPERATION: Cable shall be suitable for operation under frequency variation of +3% and voltage variation of +10% to -15% and combined frequency-voltage variation of 10% (absolute sum). Cable shall be suitable for laying in duct or buried underground. Cable shall have heat & moisture resistance properties. These shall be of type & design with proven record on distribution network service. [8] CABLE IDENTIFICATION MARK. 8.1 The cable drum shall be printed with information as per Cl of IS and ISI Certification mark. Bidder shall submit attested photo copy of valid ISI Licenses with technical bid. 8.2 For identification of cores, coloured strip of Red, Yellow and Blue Colours shall be used for identification of phases. 8.3 Following shall be embossed at intervals of length of one meter of cable outer sheath. (a) Name of manufacturer (b) Year of manufacture (c) Voltage grade (d) Name of purchaser DGVCL DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 4 /13

5 [9] DRUM LENGTH: The cable shall be supplied in standard drum length of 300 mtrs. The allowable tolerance length for all the sizes of cable shall be ± 5%. Over all tolerance in total quantity of ordered cables shall be + 2%. [10] TESTS ON XLPE CABLE: 10.1 TYPE TESTS: All the cable sizes i.e. items offered should have been fully type tested as per the relevant standards at any Govt. recognized /NABL accredited Laboratory. The bidder shall furnish the type test reports for relevant 22 KV Cable rating for the size offered, along with the offer. These type tests must have been conducted within last five years prior to date of Bid opening. For any change in design/ type, already type tested and the design/ type offered against this specification, the purchaser reserves the right to demand repetition of type tests without any extra cost. The purchaser also reserves the right to have all tests carried out at Govt. recognized /NABL accredited Laboratory, whenever there is a dispute regarding the quality of supply. Type tests certificates for following type tests as per Cl. No of IS: (Part- II) shall be furnished invariably with the offer: Type Tests to be conducted on cable: (a) Tests on conductor : (i) (ii) Tensile test Wrapping test (iii) Resistance test (b) Tests for armouring strips / wires. : (c) Tests for thickness of insulation and sheath. : (d) Physical tests for insulation. : (i) (ii) Tensile strength and elongation at break. Ageing in air oven (iii) Hot set (iv) Shrinkage test (v) Water absorption DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 5 /13

6 (e) Physical tests on outer seath : (i) Tensile strength and elongation at break. (ii) Ageing in air oven (iii) Shrinkage test (iv) Hot deformation (v) Bleeding and blooming test (f) (g) (h) (i) (j) (k) (l) (m) Partial discharge test Bending test Dielectric power factor test i) as a function of voltage ii) as a function of temperature Insulation resistance test (volume resistivity) Heating cycle test Impulse withstand test High voltage test Flammability test 10.2 ACCEPTANCE TESTS: Acceptance Tests to be conducted on cable The selection of sample pieces for acceptance test shall be from 10% drums of each lot offered for inspection or part thereof. The minimum shall be one drum. The following acceptance tests shall be carried out on the selected samples as per IS: 7098 (Part-II) (i) Annealing test (for copper) (ii) Tensile test (for aluminum) (iii) Wrapping test (for aluminum) (iv) Conductor resistance test. (v) Test for thickness of insulation and sheath (vi) Hot set test for insulation (vii) Tensile strength and elongation at break test for insulation and sheath. (viii) Partial discharge test (for screened cables only) (ix) High voltage test for 4 hours (x) Insulation resistance (volume resistivity) test DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 6 /13

7 All the acceptance tests shall be carried out by the firm, in the presence of purchaser s representative at their works. The firm shall give at least 15 days advance notice to the purchaser to enable him to depute the engineer for witnessing the tests ROUTINE TESTS: Routine Tests to be conducted on cable The bidder shall have to submit, reports of the test for the following routine test along with inspection call letter for the materials offered for inspection. (i) Conductor resistance test (ii) Partial discharge test (iii) High-voltage test 10.4 STAGE INSPECTION: The inspection may be carried out by the purchaser at any stage of manufacture. The successful bidder shall grant free access to the purchaser s representative at reasonable time, when the work is in progress. Inspection and acceptance, of any cables under this specification by the purchaser, shall not relieve the supplier of his obligation of supplying cable in accordance with the specification and shall not prevent subsequent rejection, if the cables are found defective. The purchaser reserves the right to insist for witnessing the acceptance / routing tests of the bought out items. [11] The supplier shall keep the purchaser informed in advance about the programme of manufacturing of cables so that arrangement can be made for inspection. [12] DOCUMENTATION: The bidder shall furnish following documents along with his offer Drawing of cable drums with details of material dimension and paint etc Sectional view, showing the General constructional feature with conductor / conductor screen / insulation / armouring / inner and outer sheath etc All the required type test reports for offered items tested at any Government recognized Laboratory as stated under Clause No (B) 12.4 List of orders executed during last Three years for supply of specified sizes of XLPE cables, supplied to DGVCL/ MGVCL/ UGVCL/ PGVCL/ GETCO/ GUVNL (formerly GEB) / Other SEB s, Power Utilities etc. along with quantity, value of the orders, year of supply, delivery schedule and Literature, pamphlets for the record items. List of orders executed and under execution shall be submitted separately. DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 7 /13

8 The annual turn over in rupees during last three years shall be stated. [13] PACKING AND FORWARDING: 13.1 The cable shall be wound on wooden drums as per IS: and packed in drums suitable for vertical / horizontal transport, as the case may be and shall be suitable to withstand rough handling during transport and outer storage. The outer surface of the drum shall be painted with white aluminum paint. Similarly, the inside surface of drum shall have the protective layer of varnish / paint to protect it from white ants The wooden drums shall be reinforced with steel bends and strips for better protection The ends of the cable shall be sealed by means of non-hygroscopic sealing materials The following information may be stenciled on the drum with either water proof ink or oil paint: (i) Reference of IS / IEC standard. (ii) Manufacturer s name or trademark. (iii) Type of cable and voltage grade. (iv) No. of cores. (v) Nominal cross-sectional area of conductor. (vi) Cable code. (vii) Length of cable on the drum (viii) No. of lengths on the drum (if more than one) (ix)) Direction of rotation of drum (by means of an arrow) (x) Position of outer end of cable (xi) Gross weight (xii) Country of manufacture (xiii) Year of manufacture (xiv) Reference of A/T No. & date (xv) Property of DGVCL (xvi) Name of consignee and the destination. The drum may also be marked with ISI Certification Mark. Over and above, name plate of aluminum of suitable size and thickness, containing all the above information, shall be fixed on the drum in addition to the painting The firm shall be responsible for any damage to the cables during transit due to improper and inadequate packing. Wherever necessary, proper arrangement for lifting, such as lifting hooks, shall be provided. Any cable found short inside the packing cases shall be supplied by the supplier, without any extra cost. DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 8 /13

9 13.6 Each consignment shall be accompanied by a detailed packing list, containing the following information: 1) Name of consignee 2) Details of consignment 3) Destination 4) Total weight of consignment 5) Handling and unpacking instruction 6) Bill of materials, indicating contents of each package. [14] TECHNICAL AND GUARANTEED PARTICULARS: The bidder shall furnish all Guaranteed Technical Particulars, as called for, in Appendix - I of this Specification. Particulars, which are subject to guarantee, shall be clearly identified. Offer not containing this information will not be considered for acceptance. [15] Performance Certificate: Bidders shall also submit performance reports for the specified size of cables supplied to other SEB s/power Utilities, with the clear indication of the period since when the cables performed satisfactory service. SEAL OF THE FIRM SIGNATURE OF THE TENDERER #################### DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 9 /13

10 APPENDIX I SCHEDULE OF GUARANTEED TECHNICAL PARTICULARS FOR 22KV XLPE CABLE (To be filled in and signed by the Tenderer) 1 Name of Manufacturer 2 Place of Manufacturing 3 Design ambient temperature ºC 4a Technical details of XLPE Cable: 4b Voltage grade (Uo / U) 4c Whether suitable for neutral earthed / unearthed System 4d Permissible voltage & frequency variation for satisfactory operation 4e Nos. of cores & size 4f 4f(i) 4f(ii) Continuous current carrying capacity For standard condition as per IS In air (Amp) In ground (Amp) In duct (Amp) In trench (Amp) For site condition In air (Amp) In ground (Amp) In duct (Amp) In trench (Amp) 5 CONDUCTOR: 5a 5b Material & its applicable IS. Shape of conductor 5c Nominal cross section area (mm 2 ) 5d 5e Number of wires per core Nom. dia & CS area of wire used in cores 6 CONDUCTOR SCREENING: 6a 6b Type Material & its applicable IS. 6c Continuous working temp ºC 6d Nominal thickness (mm) DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 10 /13

11 7 INSULATION: 7a 7b Material & its applicable IS Thickness of insulation (mm) 7b.1 a) Between cores 7b.2 b) Between cores & inner sheath 7c Diameter of core over insulation (mm) 7d Specific insulation resistance at ninety (90º) Centigrade (Ohm-Cm) 8 INSULATION SCREENING: 8a 8b Material & its applicable IS. Thickness (mm): 8b.1 Semi-conducting part 8b.2 Metallic part (copper tape) 8c 8d Overlapping provided for copper tape Current carrying capacity 8d.1 Continuous (Amps.) 8d.2 S.C. current duration 3-Sec. (KA) 9 Diameter of core over screening (mm) 10 FILLER: (whether suitable for operating temp or not? 10a Material & its applicable IS 10c No of fillers provided 11 INNER SHEATH: 11a 11b 11c 11d Material & its applicable IS Extruded or wrapped Thickness (mm) Diam. of cable over inner-sheath (mm) 12 ARMOURING: 12a 12b 12c 12d 12e Material & its applicable IS Type of armouring Nos. of strips Diameter of cable over armouring Current carrying capacity of armour 12e.1 On continuous basis (Amp) Yes/No DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 11 /13

12 12e.2 SC current duration of 1 sec (KA) 13 OUTER SHEATH: 13a 13b 13c 13d 13e Material & its applicable IS. Thickness of sheath Tolerance on thickness of sheath Over all diameter of cable (mm) Scheme for identification 14 CABLE CONSTANT: 14a AC resistance per core at operating temp. (Ohm/KM) 14b DC resistance / core at 20ºC (Ohm/KM) 14c 14d 14e 14f Reactance per core (Ohm/KM) Capacitance per core (Microfarad/ KM) Insulation resistance at 27ºC (Ohm/ KM) Loss tangent 14g Dielectric constant 14h Maxi. Cable charging current at normal operating voltage (Amp/KM) 15 OTHER PARAMETERS: 16 Recommended min.bending radius (mm) 17 Safe pulling force 18 Cable weight (Kg./KM) 19 CABLE DRUM: 19a 19b 19c 19d 19e Net weight of cable (Kg.) Drum weight (Kg.) Shipping weight (Kg.) Whether ISI Mark is on drum Length of cable per drum (Meter) Whether details shall be embossed as stated under Cl. 8.3 of Technical Specification (Yes/No) Whether type test reports submitted, as stated under Cl of Technical Specification (Yes/ No) Whether drawings submitted as specified under Cl of Technical Specification. (Yes/ No) Whether unpriced schedule of offered items submitted with Technical offer. (Yes/ No) DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 12 /13

13 24 Applicable Standard IS/IEC 25 Cable parameters, whether conformed as per clause No.5 of Technical Specification Signature of Tenderer Seal of Company DGVCL/SP/8020/22KV XLPE Cable /Tech.Spec. & GTP 13 /13