电站电缆技术要求-1

Ref. No. 300985Date December, 2009STANDARD SPECIFICATION E – 210CABLES AND WIRESSTANDARD SPECIFICATIONSE-210 CABLES AND WIRESTABLE OF CONTENTS1SCOPE OF WORK (1)2CODES AND STANDARDS (1)3DESIGN AND OPERATING CONDITIONS (1)3.1GENERAL (1)3.2CABLE SIZING CRITERIA (2)3.2.1Voltage Drop (2)3.2.2Cable Ratings (2)3.2.3Short Circuit Current Capacity (3)4DETAILED REQUIREMENTS (3)4.1GENERAL (3)4.2CABLE CONSTRUCTION (3)4.2.1Conductors (core) (3)4.2.2Insulation (4)4.2.3Conductor Jacket (4)4.2.4Bedding (inner covering and fillers) (4)4.2.5Armour (4)4.2.6Lead Sheath (4)4.2.7Outer Jacket (5)4.2.8Cable Splice and Rework (5)4.3SPECIFIC REQUIREMENTS (5)4.3.1Power Cables (5)4.3.2Control Cables (6)4.3.3Instrumentation Cables (6)4.3.4Thermocouple Extension Cables (7)4.3.5Special Application Cables (7)4.4CABLE INSTALLATION (7)4.4.1General (7)4.4.2Cable Splices (8)4.4.3Draw Pits and Joint Pits (8)4.4.4Preparation of Cable Trays and Trenches (9)4.4.5Preparation of Conduits and Ducts (9)4.4.6Cable Pulling Equipment (9)4.4.7Cable Pulling and Installation (10)4.4.8Pulling Tensions (12)4.4.9Protecting and Supporting Cables (13)4.4.10Cable Trenches and Cable Ducts (14)4.5CABLE FIRE BARRIERS (14)5TESTING AND FUNCTIONAL GUARANTEES (14)5.1CABLE TESTS AND TEST REPORTS (14)5.2MANUFACTURING TESTS (15)5.2.1Routine Tests (15)5.2.2Type Tests (15)5.3TEST AFTER INSTALLATION (15)5.4GUARANTEE (15)6CABLE NUMBERING SYSTEM (15)7QUALITY ASSURANCE/QUALITY CONTROL (QA/QC) (17)1SCOPE OF WORKThe work shall include the design, supply, manufacturing, factory testing, delivery to site, in-stallation, commissioning and testing of all cable and wires for power, control and instrumen-tation cables for this Project.The Bidder shall give clear and comprehensive information concerning the power, control andinstrumentation cable types that are to be provided, by completing Technical Schedule TS E-210, together with manufacturer's catalogues and technical information publications etc.2CODES AND STANDARDSThe Contractor shall comply with the requirements of Volume II, Part I, Section 2, Clause 2.5"Codes and Standards" and the following specific standards.IEC 60227 Polyvinyl chloride insulated cables of rated voltages up to and including450/750 VIEC 60228 Conductors of insulated cables.IEC 60230 Impulse tests on cables and their accessories.IEC 60245 Rubber-insulated cables of rated voltage up to and including 450/750 V.IEC 60287 Calculation of the continuous current rating of cables (100 % load factor).IEC 60332 Tests on electric cables under fire conditions.IEC 60502 Extruded solid dielectric insulated power cables for rated voltages from1 kV up to 30 kVIEC 60584-3 Thermocouples - Extension and compensating cable. Tolerances and identi-fication system.IEC 60811 Common test methods for insulating and sheathing materials of electric ca-blesIEC 60885 Electrical test methods for electric cables3DESIGN AND OPERATING CONDITIONS3.1GENERALPower, control, instrumentation, communication, thermocouple extension and special applica-tion cables shall have a minimum design life of 30 yrs when used under the following operat-ing and design conditions.Operating Voltages:System operating voltage levels are in accordance with Standard Specification E-001.Operating Temperatures:The maximum operating temperature of XLPE insulated conductors shall be 90 ºC.An emergency overload temperature of 130 ºC and a maximum short circuit tempera-ture of 250 ºC will be permitted for duration and frequencies as specified in the refe-renced IEC standards.Load Factor:The maximum load factor shall be 100 %.Installation:The cables shall be suitable for indoor and outdoor installations exposed in air, in con-duits, in cable trays, in underground concrete encased steel or plastic conduits, in un-derground trenches and for direct burial. Un-armoured cables shall be suitable for in-stallation in steel conduits.Environmental Conditions:The meteorological, seismic and environmental conditions for the Site are as indicatedin Volume II, Part I, Section 1, Clauses 1.3 “Site Conditions”.For cables installed in air the maximum continuous ambient temperature shall be assumed tobe 50 ºC.3.2CABLE SIZING CRITERIAThe Contractor shall use the following criteria for selecting and sizing the cables:3.2.1Voltage DropThe total voltage drop between main bus and the final equipment terminals in feeder andbranch circuits shall not exceed 5 % of bus nominal voltage. Individual branch circuit voltagedrop shall be a maximum of 3 % during normal operation and 10 % during motor starting.The voltage drop calculation for equipment shall be based on the rated nominal voltage of thedistribution bus feeding the equipment, full load current of the equipment being fed at its ratedvoltage and maximum feeder cable impedance.The voltage drop in control circuit wiring shall not exceed a value that may cause contractorsto drop out, or cause auxiliary relays or contractors to fail to pick up or the control system tomalfunction in other way under any auxiliary system voltage condition, including during thestarting of large motors. In critical cases, voltage drop calculations shall be done for controlcircuits and larger size conductors shall be used as necessary to ensure proper operation of thecontrol system.3.2.2Cable RatingsThe nominal cable ratings shall be rated based on the method of installation and groupings inaccordance with the cited standards as follows:•Cables ratings in concrete duct banks shall be calculated in accordance with IEC 60287, based on a soil thermal resistivity of not less than 1.2 K.m/W(Kelvin-metre/Watt) and a soil temperature of not less than 30 o C.•Cables in cable trays shall be sized in accordance with IEC 60287 applying appropriate derating factors according to a recognised standard which take ac-count of the ambient conditions and installation conditions. The depth of fillshall not exceed 50 mm for power cables. Sufficient design margin shall beprovided in sizing the cable trays so that 10 % more cables can be added by theOwner in the future. The effect of covers and solar radiation on outdoor cabletrays shall be taken into account in sizing calculations.•Cables in conduits shall be sized in accordance with IEC 60287.Other de-rating factors, which shall be considered, are as follows:a. The ambient temperature at the termination point shall be considered to be 50 ºC.b. 10 % de-rating factor due to current unbalance when two or more conductors per phaseare used.c. The Contractor's cable rating calculations shall be submitted to the Owner for review.All cables shall have adequate conductor sizes to carry the full starting current of the motors,during the period of motor acceleration without exceeding the specified short duration con-ductor temperature of 130 ºC.3.2.3Short Circuit Current CapacityThe cable designs shall be fully co-ordinated so that they are fully capable of sustaining theSpecified ground fault currents without damage to the metallic screen, metallic sheath or ar-mouring etc.The short-circuit capability shall be based on using the total operating time for protective re-lays and breaker fault clearing time or on the fuse let-through current and energy.Under worst conditions, the conductor temperature shall not exceed its maximum short circuittemperature of 250 ºC.The Contractor's calculations for cable short circuit current capacity shall be submitted to theOwner for review and approval.4DETAILED REQUIREMENTS4.1GENERALInterconnecting wiring to control components such as flow, pressure and limit switches, tem-perature devices, solenoids, 230 V a.c. motor drives, etc., local control cabinets or junctionboxes shall be wired in strict accordance with Contractor's Drawings. Refer to Volume II, PartI, Section 2, Clause 2.2 "Data and Drawing Submission".All terminals and wires shall have identifications as shown on Contractor's schematic and wir-ing diagrams. All wiring shall be installed exactly as shown on the "for construction" wiringdiagrams.Wiring between equipment, or equipment and terminal blocks mounted on the same skid orshipping section shall be continuous with no splices.Single conductor control cables shall not be run in cable trays.Cables outside of an enclosure or junction box shall be protected by conduit or shall be ar-moured. If armour is used without conduit it shall meet the requirements of Clause 4.2.5.4.2CABLE CONSTRUCTIONThe cables shall be single conductor or multi-conductor assemblies, as specified.4.2.1Conductors (core)All conductors, except thermocouple extension cables, shall be Class 2, annealed strandedcopper in accordance with IEC 60228.Thermocouple extension cable conductors shall be solid and conductor materials shall be perIEC-60584-3.Conductors shall be coated or other means shall be provided to ensure clean stripping of insu-lation and/or conductor shield.The medium-voltage power cable conductors shall be provide with a layer of extruded semi-conducting compound with an average thickness of 0.38 mm and minimum thickness of notless than 0.30 mm.4.2.2InsulationThe insulation shall be a high quality, non-flame propagating, ozone resistant extruded soliddielectric of either ethylene propylene rubber (EPR) or cross-linked polyethylene (XLPE) forPower Cable and PVC (coaxial or not) for instrument control and communication.For high temperature (125-150 ºC) applications silicone rubber or Tefzel insulation shall beused as reviewed by the Owner.The average insulation thickness for power cables shall not be less than the nominal valuesspecified in Tables III and IV of IEC 60502. The thickness of any separator or screen on theconductor or over the insulation shall not be included in the thickness of the insulation.4.2.3Conductor JacketAll power cables shall be provided with a fire retardant and low acid and gas evolution jacketover the individual conductors. This jacket shall be of heavy duty chlorosulfonated polyethyl-ene (Hypalon) or polychloroprene (Neoprene) or PVC.The details of the fire retardancy and related tests shall be submitted with the Tender Proposal.4.2.4Bedding (inner covering and fillers)Multi-conductor cables shall have bedding, which shall be suitable for the specified operatingtemperature and insulating material. The bedding material shall be termite resistant.All cables shall be provided with water-blocking material.4.2.5ArmourAll multi-conductor cables shall be provided with continuous, close fitting, galvanised steelwire armour unless otherwise indicated or accepted in writing by the Owner. The armourgrounding shall be in accordance with Standard Specification E-217 "Building and EquipmentGrounding and Lightning Protection".Single conductor power cables shall be armoured with non-magnetic corrosion resisting ar-mour. The maximum armour voltage to ground shall not exceed 25 V.The armour shall be impervious to attack by termites, rats and other vermin.4.2.6Lead SheathCables subject to permanent or prolonged contact with water shall be provided with a leadsheath.4.2.7Outer JacketAll cables shall be provided with a fire retardant and low acid gas evolution outer jacket overthe armour. This jacket shall be of heavy-duty chlorosulfonated polythylene (Hypalon) orpolychloprene (Neoprene). Polyvinyl chloride (PVC) outer jackets may be used for cables inoutside trenches or ducts provided they do not enter a building or similar enclosure.The details of fire retardancy and related tests shall be submitted with Tender Proposal.All cables shall be permanently identified by permanent surface printing or indenting (not toexceed 15 % of the outer jacket thickness) to show the following:•Manufacturer’s Name•Rated Circuit Voltage•Conductor Size•Number of Conductors•Insulation Material (not trade name)•Jacket Material (not trade name)•Year of ManufactureThe distance between the end of one complete set of marks and the beginning of the next shallnot exceed 500 mm. All marking shall be legible and shall be made with colours in contrastwith the outer jacket colour.4.2.8Cable Splice and ReworkFactory cable splices and/or rework of the insulation and jacket is prohibited unless agreed toby the Owner in writing, in which case the following shall apply:a. Splices and/or rework of the insulation and jacket may be required during manufacturingto eliminate defects, obtain specified shipping lengths, etc. Any such rework of splicesshall conform to the material, dimensional and test requirements of the cable.Conductors and cables, which have been reworked or spliced, shall be tested as requiredfor the specified cable and manufacturer shall include with his test reports the results ofany tests for such rework and splices. Factory splices shall be made so that individualstrands of the conductor are butt-brazed and the brazes are staggered at intervals of atleast 5 mm.b. Materials for splices and rework shall be controlled and documented in accordance withthe quality assurance/ quality control requirements as referenced in Clause 6.Field cable splicing and/or rework is prohibited in all but exceptional cases4.3SPECIFIC REQUIREMENTS4.3.1Power CablesMedium-voltage cable:•10 kV rated 8.7/15 kV (highest system voltage 12 kV)Earthing conditions are in accordance with Category A of IEC 60502.Low-voltage power cables may be single, two, three or four conductor cable with a voltage rating of 0.6/1 kV.The minimum conductor size for power cables shall be 2.5 mm².All power cable conductors shall be identified by colouring the individual conductor jackets as follows:Number of Conductor PhaseLetterDesignationColourThree 1, 2, 3 L1, L2, L3 Red, Yellow, Blue- Neutral N Black- Protective Earth PE Green-Yellow DC - cables- Positive L+ Grey- Negative L- Blue The outer jacket shall be coloured black for medium-voltage cables and black for low-voltagecables.4.3.2Control CablesControl cables shall be rated 600 V.The minimum conductor size for control cables shall be 1.5 mm².The minimum conductor size for current transformer secondary circuits shall be 2.5 mm².Each conductor shall be identified by numbering and/or colour codes.The insulation of all individual conductors shall be the same colour (black, white or natural),with surface printing of numbers in sequence.The outer jacket shall be coloured black.4.3.3Instrumentation CablesInstrumentation cables shall be rated 600 V. Instrumentation cables shall be shielded twistedpairs.The minimum conductor size shall be 0.5 mm². Conductors shall be chosen as stranded type,suitable for connection via Maxi-Termi-Point technique.Each pair shall be twisted with a lay of approximately 50 mm.The cable shall be composed of conductor bundles, each bundle comprising 4 pairs (excep-tion: 2-pair cable shall have two bundles). The 4 pairs of each bundle shall be twisted (1twist/m) and the bundles shall be twisted to form the cable (1 twist/m).Each multiple pair cable shall be provided with an overall shield of copper or plastic coatedaluminium foil and one drain wire.The minimum drain wire conductor size shall be 0.5 mm² for all instrument cables. The drainwire shall be in intimate contact with the metal part of its shield.The conductor-ident-code shall be as follows:Pair-No. Conductor A Conductor B1 blue red2 grey yellow3 green brown4 white blackIdentification of different bundles shall be made by numbered plastic foilFor instrumentation cables the outer jacket shall be coloured grey.4.3.4Thermocouple Extension CablesThe cables shall be rated for 600 V and shall consist of single or multiple twisted pairs withindividual drain wires and shields (plastic coated aluminium foil or copper). The cables shallalso have an overall shield, drain wire and jacket and be of similar construction to instrumentcables, Clause 4.3.3.Multiple-pair thermocouple extension cables may use a minimum conductor size of 0.75 mm².The thermocouple extension cable conductor materials shall be thermocouple materials as re-quired for the application chromel-constantan, chromel-alumel, etc.The colours shall be in accordance with IEC-60584-3 and as follows:Cable TypeColour of InsulationPositive - Negative Colour of Overall JacketChromel-Alumel Yellow – Red YellowChromel-Constantan Purple – Red PurpleMultipair cables shall consist of pairs of conductors with colours as indicated above. The pairsshall be identified by surface printing of numbers in sequence on each conductor of each pair(same number on each conductor of a given pair).4.3.5Special Application CablesThe Contractor shall provide all special application cables required for various equipmentprovided as part of the Work.In general, the cables shall meet the requirements specified herein for a 30 yrs design life ofthe Power Plant.The Contractor's recommendations on the type and construction of the cable for these applica-tions shall be given due consideration.4.4CABLE INSTALLATION4.4.1General。