power transer tender documents.doc

PEC Technical Specification Power TransformerSPECIFICATION CONTENTSDESCRIPTION.PAGE NOSECTION (1) General Requirement21.1 SCOPE1.2 STANDARDS1.3 SERVICE CONDITIONS1.4 UNITS OF MEASUREMENT1.5 DEPARTURE FROM SPECIFICATION1.6 DRAWINGS1.7 INSTALLATIONS AND PARTS LIST1.8 PACKING1.9 CLEANING AND PAINTING21.10 RATING AND CONNECTION PLATE2SECTION (2) Technical Specification and Requirements2.1 DETAILED REQUIREMENTS2.2 INSULATION LEVELS AND CLEARANCES2.3 TYPES OF TRANSFORMERS AND OPERATING CONDITIONS32.4 CONTINUOS MAXIMUM RATINGS AND OVERLOADS2.5 ELECTRICAL CONNECTIONS2.6 DUTY UNDER FAULT CONDITIONS2.7 FLUX DENSITY2.8 LOSSES AND EVALUATION OF LOSSES2.9 VIBRATION AND NOISE2.10 SUPPERESSION OF HARMONICS2.11 MAGNATIC CIRCUIT2.12 MECHANICAL CONSTRUCTION OF CORES2.13 WINDINGS2.13.1 General2.13.2 Bracing of Windings2.13.3 Tertiary Windings2.14 INTERNAL EARTHING ARRANGEMENTS2.15 EARTHING OF TERTIARY WINDING2.16 TANKS2.16.1 Tank Construction2.16.2 Tank Lifting and Haulage Facilities2.16.3 Tank Cover2.17 CURRENT TRANSFORMER ACCOMMODATION2.18 AXLES AND WHEELS2.19 CONSERVATOR VESSELS, OIL GAUGES AND BREATHERS2.20 FILTER AND DRAIN VALVES, SAMPLING DEVICES AND AIR RELEASE PLUGS2.21 VALVES2.22 PRESSURE RELIFE DEVICE2.23 EARTHING TERMINAL2.24 RATING, DIAGRAM AND AND PROPERTY PLATES2.25 JOINTS AND GASKETS2.26 COOLING PLANT2.26.1 General2.26.2 Radiaters Connected Directly to The Tank32.26.3 Coolers2.26.4 Oil Piping and Flanges2.26.5 Pumps2.26.6 Blowers and Ducts2.26.7 Cooler Control2.27 VOLTAGE CONTROL32.27.1 Voltage Control Equipment2.27.2 Automatic Voltage Control2.27.3 Remote Control Panel2.28 TEMPERATURE INDICATING DEVICE AND ALARMS2.29 GAS AND ACTUATED RELAYS2.30 EXTERNAL WIRING2.31 TRANSFORMER TERMINALS2.31.1 Cable Box2.31.2 Outdoor Terminal Bushing2.32 DRYING OUT2.33 DRAWINGS2.34 TESTS52.34.1 Routine Test2.34.2 Type tests2.34.3 General Test2.34.3.1 Voltage Control Equipment2.34.3.2 Magnetic Circuit2.34.3.3 Porcelain Insulators2.34.3.4 Tanks2.34.3.5 Gas and Oil Actuated Relays2.34.3.6 Cable Boxes and Disconnecting Chambers2.34.3.7 Galvanising2.34.3.8 Information to be Supplied3 SCHEDULE83.1 CHEDULE Tr-01 TECHNICAL PARTICULARS84 NON COMPLIANCE SCHEDULE105 TEST CERTIFICATE SCHEDULE11PUBLIC ELECTRICITY CORPORATION SPECIFICATION FORPOWER TRANSFORMARSpecification No. Tr-01Date: Mar-2000SECTION (1): General Requirement1.1 SCOPE:Includes the design manufacturer testing, packing for export, shipment and delivery of the equipment described in the specification and schedule of requirement.1.2 STANDARDS:Unless another standard is specifically mentioned in this specification all materials and equipment supplied and all design calculations and tests shall be in accordance with international standard Organization (ISO) for mechanical equipment and international electrotechnical commission (IEC) recommendations for electrical equipment.1.3 SERVICE CONDITIONS:Transformer shall be suitable to ensure satisfactory operation for the following altitude, climatic and atmospheric site conditions:a Altitude:from sea level up to 2300m will be subjected to lightning strokes.b Ambient temperature:-5C up to 50C.c Wind pressure: (kg/m2)80 130d Seismic acceleration: (g)0.12 - 0.05e Isokeraunic level:10 18f Relative humidity:5 100g Solar radiation: 1200W/mh Atmosphere: Heavy salt and dust laden pollution in coastal areas, moderate sandstorm exposure and dust pollution in low to mid altitude and region and light to heavy dust pollution at high altitudes.1.4 UNITS OF MEASUREMENT:In all correspondence, on all technical schedules, on all drawings and for all instruments SI units of measurement shall be employed.1.5 DEPARTURE FROM SPECIFICATION:Any departures from specification shall be stated by the Tender in the schedule of Departures. The Purchaser (PEC) may or may not approve such departures.1.6 DRAWINGS:General Arrangement drawings and typical detail of the essential items of equipment offered. Two copies of each drawing are required.After the award of contract drawings and diagrams showing all detail of the plant and materials to be used are to be submit to PEC for approval. The drawings submitted are to be modify as necessary if requested by PEC and re-submitted for final approval.After all item of plant have been manufactured and before shipment. 4 copies of each drawing previously approved is to be provided together with installation, Operation and Maintenance instructions.1.7 INSTALLATIONS AND PARTS LIST:The tendrer is to submit to PEC 4 copies of fully detailed operation and maintenance instructions and parts test for all equipment supplied.The detail is to cover the main equipment and all associated ancillary equipment as supplied. It will not be sufficient to incorporate manufactured standard brochures part of the text unless they refer particularly to the equipment supplied.1.8 PACKING:Each crate or package shall contain a packing list in a waterproof envelope and applies in duplicate shall be forwarded to prior to dispatch.All cases package etc are to be clearly marked on the outside to indicate the total weight, to show where to weight is bearing and the correct position of the shings and are to bear an identification mark relating them to the appropriate shipping documents .In addition to the above each case of a transformer shall be further identified by Purchaser name, the kVA rating, the transmission ratio and the words “STEP UP” or “STEP DOWN” where appropriate.Each transformer shall be packed separately and properly protected for transport and shipment from the place of manufacture to the port of destination.For shipping, transformer cores and windings shall be immersed in oil, and all breathers and vents sealed, The balance of any oil to be shipped shall be in strong hermetically sealed drums, which if stored in the open shall be kept in a horizontal position.The supplier shall describe the proposed method of packing for transport and shipment.Tube ends other open ends shall be protected from both external damage and ingress of dirt and moisture during transit and while awaiting erection of site . Flanged pipes shall have their open ends protected by adhesive tape or jointing and then be covered with a wooden blank flange secured by service bolts.Lids and internal cross battens of all packing cases shall be fixed by screws and not nails.Contents of cases shall be looted securely or fastened in position with struts or cross battens and not with wood chocks wedged in place. All struts or cross battens are preferably to be supported by cleats fixed to the case above and below to from legs.1.9 CLEANING AND PAINTING:Paint shall be applied by the flood or spray method, the former being preferred. the inside and outside of the tank covers shall be treated in the same manner as the inside an outside, respectively, of the tanks.The cleaning and painting shall comply with the following :1.9.1 The internal of the tank shall be thoroughly cleaned by shot blasting and the surface shall be given one coat of oil resisting paint or varnish.1.9.2 The exterior of steel tanks, complete with tubes or radiators where applicable, shall be zinc sprayed. the zinc deposited shall be not less than 550g/m2 .This treatment shall be applied immediately after shot blasting as a follow up process , on the same day without outdoor exposure .after the above treatment the exterior of all tanks shall be given one coat of zinc chromate base priming paint, applied as soon as practicable after the zinc spraying .two coats of durable oil and weather resisting paint, of contrasting colors shall subsequently be applied. the final coat shall be dark admiralty Grey, color No.632 of BS 381C.1.9.3 Radiators which are hot dip galvanized to BS 729, part 1, are to be artificially weathered and given one coat of zinc chromate primer followed by the same number and type of paint coatings specified above.1.10 RATING AND CONNECTION PLATE:Transformers shall be fitted with a rating and connection plate of durable and non-corrodible material.The rating and terminal marking plates shall bear the information called for in BS 171:1971 except that a ) weights shall be stated in kilograms, b) quantities of oil shall be stated in liters. A connection plate shall also be provided to show the winding connection and tappings in tabulated form.Space shall be provided in the rating plate for the purchasers own serial number allowing for ten digits.Rating and connection plates may be combined into a single.SECTION(2): Technical Specification & Requirements2.1 ELECTRICAL SYSTEM AND FAULT LEVELS:The transformers shall be suitable for continous operation on a three phase, 50hz system at the voltages specified and, unless specifically stated otherwise, the neutral earthing conditions for these system will be as follows:-11kV Distribution System -Solidly earthed33kV Transmission system-Solidly earthedThe nominal design three phase fault level of the systems will be:-33kV-31.5kA for 3 secs. at 36kV 11kV-25kA for 3 secs. at 12kV2.2 INSULATION LEVELS AND CLEARANCES:The impulse withstand levels of transformers arranged for service, but with arcing horns removed ,shall be not lower than the following when tested in accordance with the British standards.Nominal voltage 33kV11kVHighest system voltage36kV12kVImpulse withstand level170kV95kVClearances between live metalwork and earth shall not be less than those in the appropriate sections of BS.162 or the clearances and dimensions given in this specification and attached drawings, whichever is the greater. the height from ground all post type or bushing insulators shall be not less than 2.44 meters. Where the design of the transformer is limited in height, a suitable support structure shall be provided to enable the specified ground clearance to be achieved.2.3 TYPES OF TRANSFORMERS AND OPERATING CONDITIONS:All transformers shall be either core or shell type and shall be of the outdoor type but suitable for an indoor installation. Transformers with forced. cooling shall be capable of remaining in operation at full load for 10 minutes after failure of the oil circulating pumps or blowers, without injurious heating.Care must be taken to ensure the dissipation of all heat generated due to tank losses when transformers are operating with either forced or natural cooling. Ventilation equipment shall be provided for each transformer area if necessary to achieve the specified ONAF and ONAN ratings.Where transformers are designed for forced oil or air blast cooling , but are initially supplied only with natural oil cooling provision shall be made for adding the cooling plant at a later date, if required to increase the output of the transformers.All transformers shall be provided with conservator vessels.2.4 CONTINUOS MAXIMUM RATINGS AND OVERLOADS:All transformers shall be capable of operation continuously without injurious heating when operating on any tapping position and at the overloads and/or over voltage directly specified.2.5 ELECTRICAL CONNECTIONS:Transformers shall be connected in accordance with the group symbol specified.When specified a tapping shall be provided to give an alternative ratio of transformation .when operated on this tapping , the transformer shall give full rated power, as specified.Transformers with alternative ratios of transformation shall be capable of withstanding the voltage tests specified, for the most severe condition.Bushing insulators shall be mounted on transformer tank so that the HV and LV connection can be taken away horizontally clear of all obstacles.2.6 DUTY UNDER FAULT CONDITIONS:Except where modified below, it is to be assumed that the amount of generating plant simultaneously connected is such that normal voltage will be maintained on one side of any transformer when there is a short circuit between phases or to earth on the other side. Any transformer may be directly connected to an under ground or over head transmission line and switched into and out of service together with its associated transmission line.All transformers shall be capable of withstanding on any tapping and dynamic effects of external short circuits under condition stated in IEC76 part 5.Transformers with tertiary windings shall be capable of withstanding for three seconds without damage any external short circuit to earth with the neutral points on both HV and LV windings directly connected to earth.2.7 FLUX DENSITY:Unless otherwise agreed , the magnetic circuit shall be of cold rolled grain oriented sheet steel and the maximum flux density shall not exceed the figure specified when the voltage applied to any tapping is not in excess of that for which the tapping was designed.2.8 LOSSES AND EVALUATION OF LOSSES:The tenderer shall state in the schedule of particulars and guarantees guaranteed values for component losses of the total loss which shall be as low as is consistent with transport restrictions, reliability and economic use of materials.Tenders will be assessed using the following formulae:-Total cost = P + 11.65 (164.9 fe+30.5 Cu) US $WhereP = tender price of transformers.Fe = no load loss expressed in kilowatts as shown in the schedule of particulars.Cu= Full load loss expressed in Kilowatts as shown in the schedule of particulars.The acceptance of transformers yielding component losses higher than the guaranteed values shall be governed by either of the following:-a) component losses in excess of guaranteed values but within the tolerance permitted under IEC 76 part 1. Transformers shall be acceptable subject to full compliance with all technical particulars including temperature rises at CMR and subject to the tenderer accepting deduction from the contract price of charges for each kw or part thereof of component losses in excess of the guaranteed values , at the above loss evaluation rates.b) component losses in excess of guaranteed values and exceeding the tolerance permitted under IEC 76 part 1.The acceptance of transformers shall be entirely at the discretion of the employer and subject to the tenderer accepting the deducation from the contract price of charges for each kw or part thereof of component losses in excess of the guaranteed values, at the above loss evaluation rates.In the event of transformers yielding component and total losses which are either equal to or below the guaranteed values, the tenderer will not be entitled to any premium in respect of reduction in losses below the guaranteed values.c) IMPEDANCE: The value of impedance measured on normal and extreme tapping shall be as stated in the schedule and minimum and maximum values where stated in the schedule of requirements shall not be subject to tolerance. Where transformers are shall not be subject to tolerance. Where transformers are required to operate in parallel with existing units the appropriate date will be stated in the schedule of requirements.2.9 VIBRATION AND NOISE:Every care shall be taken to ensure that design manufacture of all transformers and auxiliary plant shall be such as to reduce noise and vibration to the level of that obtained in good modern practice. 2.10 SUPPRESSION OF HARMONICS:The transformers shall be designed with particular attention to the suppression of harmonic voltages, especially the third and fifty , so as to eliminate wave from distortion and any possibility of high frequency disturbances , inductive effects or of circulating currents between the neutral points at different transforming stations reaching such a magnitude as to cause interference with communication circuits.2.11 MAGNETIC CIRCUIT:The design of the magnetic circuit shall be such as to avoid static discharges, development of short circuit paths within itself or to the earthed clamping structure and the production of flux components at right angles to the plane of the laminations which may cause local heating.Where the magnetic circuit is divided into be pieces by ducts parallel to the plane of the laminations or by insulating material above 0.25mm thick, tinned copper scrip pieces shall be inserted to maintain electrical continuity between packets.The magnetic circuit shall be earthed through a link as specified below. With the link removed the magnetic circuit shall be insulated from all structural part so as to withstand the tests specified and shall subsequently be earthed.2.12 MECHANICAL CONSTRUCTION OF CORES:Care shall be exercised in the selection, treatment and handling of the core steel to ensure that as far as possible laminations are flat and the finally assembled core is free from distortion . particular care shall be taken to secure even mechanical pressure over the laminations, to prevent subsequent setting of the core and to reduce noise and vibration during operation.All parts of the cores shall be of robust design capable of withstanding any shocks to which they may be subjected during lifting , transport, installation and service.All structural members of the assembled cores shall be of steel .All castings shall be fettled and structural steel adequately cleaned and painted before being built into the structure. Any non-magnetic or high res