PART - II Technical Specification

Transcription

1 GUJARAT ENERGY TRANSMISSION CORPORATION LIMITED SARDAR PATEL VIDYUT BHAVAN RACE COURSE, VADODARA TENDER SPECIFICATION FOR Annual rate contract for Laying, Erection, Testing and commissioning of 1C, 300 mm 2 & 1C, 630 mm 2 66kV XLPE Cable for Various Line TENDER SPECIFICATION TENDER NO GETCO / 66KV CABLE ARC/ PART - II Technical Specification Sign & seal of Bidder 1

2 PART II SPECIFICATIONS FOR LAYING, INSTALLATION, TESTING & COMMISSIONING OF 1-CORE 66 KV XLPE POWER CABLES 1.1 SCOPE OF WORK: The installation, testing and commissioning work shall mainly consist of: a. Design, detailed Engineering, transportation at site, storage, laying(including civil works), jointing, terminations, testing at site & commissioning of 66 KV XLPE cable alongwith its accessories. b. Route survey of the entire length under scope of work. c. Loading / unloading of cable drums at site or from stores of Corporation d. Laying of 66 KV grade XLPE cables through buried trench with necessary clamping arrangement as per specification. e. Formation of buried cable trenches for 66 KV cables as per specification including supply and installation of warning tape, providing RCC precast cable protection covers for entire route (underground portion only), construction of jointing chambers, backfilling of trenches & restoration as per specification. f. Trench less digging where the concern authorities do not permit open cut method. g. Road crossings through RCC pipe for each Circuit and restoration of ground surface as per specification h.. Road crossings through PVC pipe (where open Excavation not permitted) for each Circuit and restoration of ground surface. i. Cable markers as per statutory requirement shall be provided all along the route at a maximum distance of 50 meters and other important locations. Also the location of underground cable shall be clearly indicated on the marker. j. Co-ordinating for installation of straight through joints & end termination for complete route. k. Supply and installation of all critical installation materials like trefoil clamps, support brackets, etc as required for complete route to avoid damages of the cable. l. Bonding of screen / sheath to the earth station through disconnecting type link boxes and SVL (sheath voltage limiter). Bidder shall suggest type of bonding for route under scope with detail calculations. Earthing stations / Earthing pits, wherever applicable for complete route shall be in contractor s scope. m. Co-Axial cable laying in PVC pipe along with cables as per attached drawing. n. The successful bidder has to carry out necessary fabrication work for end terminations at sub-station end. Similarly he shall provide ladder / tray for laying cable on towers and to provide required supports to end terminations & LA on towers. Sign & seal of Bidder 2

3 o. In entire cable trench, RCC precast slab of size 600 x 300 x 50 mm is to be provided on both the side & upper side of 1C x 300mm 2 power cable for protection purpose as shown in drawing. p. For End termination & St. through jointing work, Certificate of cable Jointing person from manufacture of cable kit for this type of job is mandatory, Site in charge will asked copy of certificate before taking up cable jointing work. 1.2 General: This specification covers installation, testing and commissioning of 38/66 KV XLPE single core power cables for following line as under. Sr. No Name of line 1 66KV 300 mm2 XLPE Cable (S/C) 2 66KV 300 mm2 XLPE Cable (D/C) 3 66KV 630 mm2 XLPE Cable (S/C) 4 66KV 630 mm2 XLPE Cable (D/C) Provision of special tools / appliances required for cable jointing and stripping / dressing and application of XLPE insulation etc. shall be made by the successful tenderer The successful tenderer shall furnish all necessary information, including drawings, manuals and instructions relating to both cable laying and jointing practice Successful tenderer has to arrange at his own for first-aid, fire protection, electricity and water requirement at site. He shall also arrange for signboard, caution board, safety & security personnel etc. on cable route Approval for installation of the underground cable route from Electrical Inspector shall be arranged by Purchaser. However, permission for commencement of work and permission for commissioning of cable after completion of laying has to be arranged by the successful tenderer Successful tenderer shall arrange space for working office, workshop & store / yard for storing requisite materials like kits, cables etc The cable laying shall have to be done, as per actual site condition at the time of execution, and as per the instruction of the engineer-in-charge The structures for termination of the cable at substation end shall be arranged by the GETCO. Necessary arrangement shall be made by the engineer-in-charge. Laying of cable also includes erection & clamping of 66KV cable on erected structures at sub-station end The Un-priced schedule of the offered item shall also be submitted in technical Bid The end of cut pieces of cables left out during executions shall be sealed to prevent ingress of any moisture in the cable before handing over to consignee. Sign & seal of Bidder 3

4 The consignee shall be concern Executive Engineer (const.), Gujarat Energy Transmission Corporation Limited, Detailed route and sectional view for laying cables are as per attached drawing The rate of laying of 66 KV Cable covers the cost of fixing of 3 phase earth box and laying of Co axial cable Civil work for all other Nala crossings, road crossing, earthing pit, straight joint chambers etc. for all the above lines shall be considered in scope of bidder The construction drawings shall got approved from Chief Engineer (Project) include the longitudinal sectional diagram of the trench for different soil strata and detailed arrangement of crossings, number of pipes, size of pipes, location and position of manholes, other details as per the technical specifications Any other items not specifically mentioned in the specifications but which are required for installation, testing, commissioning and satisfactory operation of the cable as per Indian standards / IE Rules / IE Act and local authority regulations are deemed to be included in the scope of the specification and no deviation in this regard shall be accepted The Contractor shall also be responsible for the overall co-ordination with internal / external agencies, project management, training of Company s manpower, loading, unloading, handling, moving to final destination for successful erection, testing and commissioning of the 66 KV cable Contractor will have to provide complete technical supervision during installation of cables right from transport up to testing and commissioning. The contractor shall arrange for the services of fully qualified and competent supervisors / engineers for monitoring the whole job. Competent and wellversed Semi skill labourers shall be deployed for execution All the associated civil works, which are necessary in cable laying job, shall have to be carried out completely by the Contractor at no additional cost The Cable Arrangement in trench / ground, showing the proposed installation of 66 KV power cables in Single / double (3 Nos. of single core cables per circuit in trefoil arrangement) is as per the attached drawings Contractor has to arrange on his own for the safety and security of his persons and shall also make arrangements for Safety tools and tackles, first aid, fire protection as per safety norms The Contractor has to bear with any temporary interruption that may occur during actual cable laying work, where the work with other agency is involved No idling charges or cost over run for the entire project shall be entertained. 1.3 Route Survey The bidder shall fully familiarize himself with the site and route conditions etc. The bidders are advised to visit the site and acquaint themselves with the topography, infrastructure etc. The contractor shall be fully responsible for providing all accessories, materials, system and services specified or otherwise which are required to complete the erection and successful commissioning, of 66 KV cable in all respects. All materials required for the Civil and construction / installation work shall be supplied by the Contractor. The Contractor shall do the complete design and detailed engineering. The Sign & seal of Bidder 4

5 survey shall be conducted for underground routes to finalize the route and paths for the underground cable. 1.4 Map Study: The Company shall provide tentative route map of line along with the concerned area. The Contractor shall carry out the survey before commencing the work. Contractor shall submit the final survey report for approval before implementation. The final survey report shall include at least the following: a) The distance of the cable route from the center of the road / rail / river / bridge / culvert etc. shall be indicated on the route maps as well as documented in table. b) Location of all turns, bends and major landmarks, road crossing. The survey report shall be approved by the concern and requisite clearances need to be obtained before the cable installation work is commenced. 1.5 Statutory Clearances and permissions : a) All statutory clearances and permissions from various statutory bodies/govt. authorities like forest Department, Railway, Aviation Authority, Maritime Board, National highway Authority, Municipal Corporation, Gram Panchayat (if any), PWD,Telecom Department, right of way and way leave etc. wherever required along the entire route of the cable lines shall be arranged by the Corporation. b) For necessary forest clearance, the Corporation will do the processing and the payment to the central government/state government for compensation of forest clearance will be paid by the Corporation as necessary. for permission from other Govt. authorities like railway, National highway authority etc. the payment shall be made by the Corporation. c) The scope of work shall also include assistance in obtaining required permission / approval from various statutory authorities i.e. Municipal Corporation, Gram Panchayat (if any), PWD,Telecom Department etc. in the interest of progress of the work. Payment demanded by any statutory authority as compensation shall be reimbursed by GETCO on submission of documentary evidence i.e. receipt of such payment made. d) For clearances, permissions etc. from various authorities, the Contractor shall not remain contended by simply informing the Corporation, but shall invariably assist and arrange for personal follow up to overcome the difficulties in the interest of progress of the work. 2.0 Laying and Installation. 2.1 The 66KV (E) XLPE cable shall be laid and buried in ground in accordance with all applicable standards like IS 1255 & its amendments. 2.2 (6+1) / (3+1) single core, 66 KV cable to form 66 KV Double / Single circuit as per scope indicated above, shall be laid throughout the route. However as per requirement of the field, the cables shall also have to be laid: Sign & seal of Bidder 5

6 1) In ducts 2) In RCC Hume pipes at road crossings 3) In PVC pipes at road crossings. 4) In open air / over steel rack (for end termination) 5) At varying depths due to obstructions. 6) Trench less road crossings. 2.3 The route plan of the cable is enclosed with bid documents to enable the bidder to have assessment of the work involved. However the bidder is advised to visit the site and acquaint himself with the topography, infrastructure etc. The contractor shall be fully responsible for providing all equipment, materials which are required to complete the erection and successful commissioning of 66 KV cables in all respects. 2.4 The sealing of power cable ends during the storage, execution till jointing work is completed, shall be in the scope of Contractor. In no circumstances, the cable ends shall be kept open. The damages done because of water / moisture ingress or penetration in the cables / con doctors during execution shall be recovered form the Contractor. It will be the responsibility of the Contractor to make them good or replace free of cost without affecting the completion schedules. 2.5 The cables shall be completely surrounded by a layer of sand having low thermal resistivity (selected sand) about 250 mm over & below the cable surface throughout the width of cable trench. 2.6 The excavated cable trench shall be drained of all water and the bed surface shall be smooth, uniform and fairly hard before paying out the cable. 2.7 The cable shall be rolled in the trench on cable rollers spaced out at uniform intervals. 2.8 The paying out process must be smooth and steady without subjecting the cable to abnormal tension. The cable on being laid out shall be smoothly and evenly transferred to the ground after providing the cushion. 2.9 The cables shall never be dropped. All snake bends shall be straightened. Suitable size cable stocking pulling eye shall be used for pulling the cable The new cable end seals shall be applied before starting of laying cable and shall be checked after laying and if found damaged shall immediately be resealed. Sufficient number of heat shrinkable cable end sealing caps shall be stocked at site stores for testing and jointing work. Cable end caps shall be in the scope of the Contractor After the cables have been laid in the trench and until the cables are covered with protective covering, no sharp metal, tool shall be used in the trench or placed in such a position that may fall into the trench The cables shall never be bent, beyond the specified bending radius. Minimum bending radius of XLPE insulated Cables shall be 20 X D (overall diameter of the cable) 2.13 The single core cables shall be laid either in trefoil formation or in flat formation depending upon the site exigencies Whenever cables are laid in trefoil formation, plastic cable ties shall be used at every meter to maintain the trefoil arrangement. The cable portion, which is beyond the buried route, shall have trefoil clamps (nonmetallic) of approved design installed at every meter. Sign & seal of Bidder 6

7 2.15 The identification marker shall be placed on each cable at every 2 mtrs. Interval, of adequate size fabricated from 3 mm thick, 25 mm wide aluminum strip. The marker shall be embossed by letter as stated below as applicable. GETCO 66KV Name of Line PHASE R OR Y OR B 2.16 The power cable shall be laid generally at a depth of 1500 mm and can vary, if obstacles like power cable of other rating / telephone cable / water pipe line etc, come in the way of installation. At least minimum Depth of 1000 mm shall be maintained from nearest road level The extra protection of pre-cast flat RCC slab with proportion 1:2:4 having size 600 (L) x 300 (B) x 50 (Thk) mm shall be provided about 250 mm over the power cables for complete route of the cable. The RCC slab shall be with proportion not less than 1:2:4 (M-150) and also shall have steel reinforced of 6 / 8 mm dia. steel bar (4 Nos. of 300 mm side and 5 Nos. on 600 mm side) at adequate required distance. The slab shall be given curing time of minimum 15 days The portion of pre cast flat RCC slab having size 300 (L) x 50 (B) x 600 (H) mm shall be provided between two circuits of power cables 150 mm apart from the outermost cables of each circuits for complete route of the cable Normally, the back filling shall consist of the materials earlier excavated, however, bigger stones or piece of rock should be removed OR if required new soil has to be provided and used for back filling with no extra cost The contractor has to keep 66kv power cable & material issued to him in safe custody and transport to the respective sites and will be fully responsible for any damage to or loss of any or all allotted equipments or materials supplied to him at any stage during transportation or erection or taking over of the cable line by the GETCO. The contractor has to return empty cable drum as instructed by E.I.C. The Contractor has to open site store at sub station site or at place nearby the sub station site and ensure for safe custody of all the stored materials at his own cost The Contractor shall have total responsibility for the entire materials stored, loose, semi assembled and/or erected by him at site in his custody. The Contractor shall make suitable security arrangements at his own cost to ensure the protection of all materials, equipment and works from theft, fire pilferage and any other damages and loss. It shall be the responsibility of the contractor to arrange for security till the works are finally taken over by the Corporation. 3.0 Storage and handling of Cable drum: 3.1 The cable drums must be handled correctly and properly with due care during transportation and laying of the power cable, in order to avoid damages to the cable as well as to other persons, properties and works. For damages done to any person or properties because of poor handling, Sign & seal of Bidder 7

8 the Contractor will be held responsible & GETCO reserves all the rights to recover such damages from him. 3.2 Cable drums shall be shifted from stores of the Company to site by the Contractor. Also empty drums and extra cable after laying shall be deposited back to the stores. 3.3 Drum position at work site should be properly consolidated and jacks placed on both sides of the drum to make the pay-off arrangement stable. Suitable arrangement is made to stop the drum rotation, during cable laying. 3.4 The cable shall always be pulled off from the top of the drum. 3.5 The end of cut pieces of cables left cut during execution shall be sealed to prevent ingress of any moisture in the cable and shall be brought back to the stores. 4.0 TRENCHING: 4.1 The excavation of trenches shall be commenced with proper coordination with GETCO; after all necessary clearances for the route have been obtained from the competent authorities by GETCO. 4.2 The cable trench work involves earth excavation for cable trench, back filling and removal of excess earth from site. The work site shall be left as clean as possible. 4.3 Before opening of the section of the trench, the contractor shall satisfy himself the line of the trench is clear of underground obstructions, by taking out trial pits on the line of the trench. 4.4 The exact location of each trench shall be approved at site by engineer in-charge. The trenches shall be excavated to approved formation and dimensions. If necessary, the vertical sides shall be timbered or otherwise secured to avoid damages. 4.5 The trench excavation and filling in shall be so executed that all walls, roads, sewers, drains, pipes, cables, structures, places and things shall be reasonably secured against risk of injury and shall be carried out to the satisfaction of the authorities concerned. However, if any, damages to existing services made, Contractor shall arrange and pay for any necessary repair, to make good the damages. 4.6 Contractor has to provide clearly visible fluorescent caution board painted MAN AT WORK in local language at every 30 Mtr. Distance during the work of cable installation. The caution board shall be prepared from MS structure and shall be of free standing type. The barriers shall be with red and white colored cross stripes. Warning and caution boards should be consciously displayed. Red lights as warning signal should be placed along the trench during the nights. 4.7 If any inconvenience is caused to the trespassers / road traffic during the cable installation work, Contractor has to resolve it immediately at his cost. Sign & seal of Bidder 8

9 4.8 At places where the cables cross private roads, gates of residential houses or buildings, the cables shall be laid in PVC/RCC Hume pipes and should confirm to following specification. 1. PVC Pipes with coupler shall confirm to IS: 4985: 2000, Size : 400 mm O.D. Pressure Rating : 6 kg / cm 2 Straight length : 6 mtrs. 2. RCC Hume Pipes shall confirm to IS: , NP-4 class, 4.9 The excavated material shall be properly stored to avoid obstruction to public and traffic movement. Where, owing to traffic or for reasons of safety the excavated material shall be removed from the site and returned for refilling the trench on completion of laying. The contractor, at his own cost, shall dispose off surplus material The bottom of the excavated trench should be leveled flat and free from any object, which would damage the cables. Any gradient encountered shall be gradual When the excavation of the trenches has been accurately executed, the contractor shall inform engineer in-charge for approval. Laying of cables shall not be started until engineer in-charge approves the trench. 5.0 ROAD CROSSINGS 5.1 The road cutting, whether cement concrete or asphalt road surface shall be taken after obtaining approval for cutting from the various civic authorities and work should be planned to be completed in the shortest possible time. Where necessary the work shall be planned during night or light traffic periods. 5.2 Where road crossing comes in way of laying power cable, the power cable shall be laid through NP-4 RCC Hume pipes. Spare cable shall be laid in PVC 150 mm, 6 Kg/cm 2 rating & rate shall be quoted accordingly. The required length of Hume pipe shall be arranged by the successful tenderer at no extra cost. 5.3 The RCC Hume pipe inner dia-meter shall not be less than 400 mm. 5.4 The RCC pipes to be laid shall have minimum depth in such a way that the back filling on top surface of the pipe shall be at least 600mm in depth. The pipe joints shall be smooth so that cables are not damaged during pulling & operation. 5.5 During the crossing of utilities like water line, drainage lines, telephone lines, gas lines etc, sufficient care shall be taken & protection shall be made available so that other utilities do not damage the cable mechanically and / or electrically or do not effect the performance of the cable. 5.6 NALA CROSSINGS / CULVERT CROSSINGS: The Nala crossings are to be made with separate fly-over bridges of adequate sizes to carry all the cables in required formation. The bridges are to be made at the sufficient distances from the edge of Nala considering the further expansions of roads. The strength shall be such that it should not wash away with the flow of water during heavy rain. 6.0 Trench less Digging: Sign & seal of Bidder 9

10 Trench less digging shall also be used where the concerned authorities do not permit open cut method and it is essentially required to carry out for installation of underground cables. The various methods of trench less digging such as hand / manual auguring, HDD (above 40-50m) shall be adopted based on the soil / site conditions and the requirement and exact method for trench less digging shall be finalized during detail engineering as per actual site / soil condition. The equipment used for HDD shall be capable of drilling at least 315mm diameter hole per circuit. The contractor shall propose the exact methods and procedures for implementation of trench less digging at various crossings taking into consideration the following guidelines, for approval by the Engineer In-charge. a) Excavation and backfilling of trial pits and soil investigation (if required) b) Excavation of entry and Exit pits. c) Erection of drill machine. Drilling of pilot hole. d) Placement and driving hand augur e) Reaming and widening of bore holed in steps (if required) f) Pulling of PVC pipes of 6 kg / cm2 ISI make 7.0 Reinstatement: 7.1 Filling in trenches shall not be commenced until engineer in-charge has inspected and approved the cables and accessories. The inspection should be got done on daily basis so that the trenches do not remain open unnecessarily, to avoid inconvenience to public. 7.2 Normally, the back filling shall consist of the materials earlier excavated. However, bigger stones or pieces of rock should be removed and if required new soil has to be used for back filling with no extra cost. 7.3 A pre-warning PVC yellow tape 250 mm wide and 100 microns thick (HDDPE/LLDPE) shall also be laid as per the Drawing. the warning tape shall be printed in RED letter (IN ENGLISH AS WELL AS GUJARATI) as CAUTION: VOLTS GETCO CABLE and to be placed at about 500 mm depth from ground level along the route of cable. 7.4 The contractor shall be responsible for permanent reinstatement of the upper levels, which shall be carried out to the satisfaction of engineer in-charge and the authorities concerned. 7.5 Contractor has to compulsorily spray water on the trench after it is backfilled. In case soil settles due to watering, contractor has to backfill the settled trench. 7.6 After the cables and pipes have been laid and before the trench is backfilled all joints, cable positions and pipe ducts should be carefully plotted and preserved. 8.0 CABLE ROUTE/JOINT MARKER/ IDENTIFICATION 8.1 Permanent means of indicating the position of joints and cable route shall be supplied and laid. Pre cast RCC markers shall be placed as per the field requirement, if the route passes through open fields, markers should be conspicuously visible and above ground surface. The marker should incorporate the following relevant information. Sign & seal of Bidder 10

11 1) The name of the owner GETCO 2) Voltage 66 KV Cable 3) Distance of cable from the marker. 8.2 The minimum size shall be 600 x 300 x 50 mm. It shall be at least embedded in ground up to 500 mm depth. 8.3 The exposed portions shall be painted with non-washable paints. (Preferably yellow paint). Writings shall be painted by red color. 8.4 The interval should be maximum 50 meters between two markers. It should be put at bends, curves, road crossing, etc. of cable route. 8.5 The identification marker shall be of adequate size fabricated from 3 mm thick, 25 mm x 25 mm aluminum strip. The marker shall be embossed with letter as stated below: GETCO - 66KV Line and Phase R or Y or B as the case may be. 8.6 The marker shall be tightened with nylon thread along with each cable at interval of 3 meters in such a way that it does not damage / penetrate the outer sheath of cable because of the dead weight of back filled materials or soil. 9.0 TESTS AFTER INSTALLATION: Pre-commissioning tests on site, to be undertaken by the successful tenderer shall include the following: a) Insulation Resistance of each cable drum length after laying and before jointing. b) Tests for detection of damage to outer sheath, if any. c) Serving insulation resistance after laying each cable length shall withstand a voltage of 10kv DC for one minute between each reinforcement and external conducting surface; In addition, the serving insulation resistance shall be measured and checked with the values obtained during routine factory tests. d) On completion of the cable laying and jointing work, the complete installation shall be checked with a D.C. voltage of 3 Uo applied for 15 minutes between each conductor and sheath. e) Conductor resistance of each cable of each complete circuit. f) Test for 5 min. with system voltage applied between the conductor and the screen. g) Test for 24 hours with normal operating voltage of the system. h) Continuity & Phase confirmation. NOTE: The pre-commissioning test at (f) or (g) at site to be undertaken as an alternative to the test (d) Jointing and Termination of Cables: 10.1 Contractor has to co-ordinate and provide necessary facilities for Carrying out joints / terminations Jointing work shall commence as soon as two or three lengths of cables have been laid Sufficient overlap of cables as shall be allowed for making the joints The joint bay should be of sufficient dimensions to allow jointers to work with as much freedom of movement and comfort as possible The joints of different phases shall be staggered in the jointing bay An enclosure or suitable protection cover shall be used in all circumstances wherever jointing work is carried out in the open Sign & seal of Bidder 11

12 irrespective of the weather conditions. The joint shall be in dust free, moisture free and clean atmosphere If the cable ends seals or cable ends are found to have suffered damage the cable should not be jointed, without tests and rectification The instructions furnished by the termination manufacturer shall be strictly followed for jointing/ termination work Sufficient length of spare cable shall be left in the ground, for future needs The cable shall be fixed properly using non-metallic clamps All the pre commissioning tests shall be carried out by the Bidder If any abnormality found during testing, bidder will have to rectify the same at no extra costs. Sign & seal of Bidder 12