Technical Specification-Power Transformer
Short Description
Power Transformer Specifications...
Description
TECHNICAL SPECIFICATION
POWER TRANSFORMER (With Provision for Installation/Adaptation of Sergi System)
Specificati on No.
PID/TS/PTR/1.0
Version
Date of Issuance
Total Pages
Issuing Section / Department
1.0
Feb 19, 2015
49
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TECHNICAL SPECIFICATION POWER TRANSFORMER Specification No.
PID/TS/PTR/1.0
Version
Date of Issuance
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Issuing Section / Department
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Feb 19, 2015
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CONTENTS 1.
SCOPE .......................................... ................................................................. ............................................ ............................................ ............................................ ....................... 5
2.
SYSTEM PARAMETERS ........................................... ................................................................. ........................................... ......................................... ....................5
3.
SERVICE CONDITIONS ............................................ .................................................................. ........................................... ......................................... ....................5
4.
GENERAL .......................................... ................................................................ ............................................ ............................................ ......................................... ................... 5
5.
EQUIPMENT IDENTIFICATION AND COLOR CODES ........................................ ............................................................. ....................... 6
6.
TECHNICAL DESCRIPTION .......................................... ............................................................... ............................................ ...................................... ............... 6 6.1
General Design..................................................... ........................................................................................................................ ........................................................................ ..... 6
6.2
Windings ........................................................................................................................ ....................................................................................................................................... ............... 7
6.3
Magnetic Core ...................................................... ......................................................................................................................... ........................................................................ ..... 8
6.4
Transformer Tank .................................................................................. ......................................................................................................................... ....................................... 8
6.5
Terminals ............................................................................................... .................................................................................................................................... ..................................... 10
6.6
Current Transformers Transformers .................................................................. ................................................................................................................. ............................................... 12
6.7
Cooling ....................................................................................................................................... ....................................................................................................................................... 13
6.8
Control of Cooling Units ......................................................................................................... ............................................................................................................ ... 16
7.
TAP CHANGERS......................................................... ............................................................................... ............................................. .................................... .............17
8.
PARALLEL OPERATION AND VOLTAGE VOLT AGE REGULATION ............................................ ......................................................... ............. 21
9.
PERFORMANCE CHARACTERISTICS OF MOTORS ........................................... ............................................................... .................... 21
10.
TRANSFORMER OIL.............................. ................................................... ........................................... ............................................ .................................... ..............21
11.
OIL CONSERVATOR ........................................ .............................................................. ............................................ ............................................. ......................... .. 21
12.
PIPING AND VALVES ........................................... ................................................................ ........................................... ........................................... ..................... 22
13.
MEASURING AND MONITORING EQUIPMENT ............................... ...................................................... .................................... ............. 23
14.
CONTROL CUBICLES, MARSHALLING BOXES, WIRING AND CONDUITS ............................. ............................. 25
15.
NAME PLATES PLAT ES AND OTHER DESIGNATION D ESIGNATION PLATES ............................................................ ............................................................ 26
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16.
DRAWINGS AND DOCUMENTS ......................................... ............................................................... ............................................ ............................ ...... 27
17.
TESTING AND INSPECTION ........................................... .................................................................. ............................................. ............................... ......... 27
17.1 Factory Tests Tests ........................................................ ........................................................................................................................... ...................................................................... ... 28 17.1.1 Routine Tests ........................... ............................................................................................ ........................................................................................... .......................... 28 17.2
Type Tests and Special Tests .............................................................................. ...................................................................................................... ........................ 29
17.3
Tests on Transformer Tank and Accessories Accessories .............................................................. .............................................................................. ................ 31
17.4
Site Tests (minimum requirements) ............................................................................................ ............................................................................................ 31
18.
CORROSION PROTECTION ......................................... .............................................................. ............................................ .................................... ............. 32
18.1
Responsibility and Guarantees.............................................................. ................................................................................................... ..................................... 32
18.2
Test Instruments........................................................................... Instruments.......................................................................................................................... ............................................... 32
18.3
Materials...................................................................................... Materials..................................................................................................................................... ............................................... 33
18.4 Galvanized Steel Surfaces .......................................................................................................... .......................................................................................................... 34 18.4.1 General Requirements ........................................................................................................ ........................................................................................................ 34 18.4.2 Cleaning and Surface Preparation ...................................................................................... ...................................................................................... 34 18.5 Painting at Manufacturer's Manufacturer's Premises Premises ............................................................... ......................................................................................... .......................... 35 18.5.1 Painting ....................................................................................................... ............................................................................................................................... ........................ 35
19.
CAPITALISATION OF LOSSES ........................................................... .................................................................................. .................................... ............. 36
20.
GUARANTEED VALUES AND PENALTIES ........................................................ ............................................................................. ..................... 36
21.
LOSSES ......................................... ............................................................... ............................................ ............................................. ........................................... .................... 36
22.
RATED POWER AND OUTPUT ....................................... ............................................................. ............................................. ................................ ......... 37
23.
NOISE LEVEL............................................ LEVEL.................................................................. ............................................ ............................................. ................................ ......... 37
24.
REJECTION ........................................... ................................................................. ........................................... ............................................ .................................... ............. 37
25.
TRANSPORT ............................................ .................................................................. ............................................ ............................................. ................................ ......... 37
26.
IMPACT RECORDERS......................................................... ............................................................................... ............................................ ............................ ......38
27.
SPECIFIC WORKS DATASHEET .................................... ......................................................... ............................................ .................................... ............. 39
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1. SCOPE
This part of the Specifications covers the design, manufacture, factory testing, transport, marking, packing, shipping, delivery to site, unloading and storage at site of power transformers with provision for installation/adaptation installation/adaptation of Sergi system. 2. SYSTEM PARAMETERS
Highest System Voltage System Frequency Nominal Voltage Short Circuit Level BIL
: : : : :
145 kV 50 Hz 132 kV 40kA for 3.0 seconds 650kV (peak)
3. SERVICE CONDITIONS
a. b. c. d. e. f. g. h.
50oC 40oC 0oC 95% at dry bulb Temperature of 45oC Altitude Altitud e Does not exceed 1000m Location Sea-coast Wind speed 160 KM/hr. Rain, condensation and heavy pollution shall be considered while designing Peak ambient air temperature Mean maximum maximum temperature during 24 hours Minimum temperature Maximum relative humidity
4. GENERAL
The power transformers shall be designed and arranged in full compliance with all applicable Sections, Articles, and Specific Works Data Sheets of these Specifications and no deviation would be acceptable. The supplier/Tenderer/Contractor shall submit with his offer a list of similar transformers already delivered by the manufacturer proposed. Past supply records of similar ratings of transformers for 15 years shall be submitted in detail with the offer. The following engineering data shall be submitted with the offer: (a) Technical schedules, all drawings with all information (b) Type test certificates, for similar transformers as offered (c) Type test certificates for different bushings, surge arresters and tap changers (d) Certificates for short circuit tests and temperature rise tests performed on transformers with similar transformer as offered. (e) Quality system certificate (f) General arrangement of transformer showing all dimensions (g) Details of all cable boxes and bushings (h) Details of tap changers, thermometers etc.
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(i) Deviations from Tender Specifications, brochures etc. (j) Foundation drawings (k) Necessary drawings of provision for installation/adaptation installation/adaptation of Sergi system (l) Reference list and Customer certificate of successful operation from major utilities. Please note following:
(i) In case, the Tenderer/Contractor/Supplier is not able to produce Type Test/Special Test Certificates for similar rating equipment certified from independent international accredited laboratory to the satisfaction of Engineer/Company Engineer/Company then, he has to make arrangement for conducting conducting such tests at an independent international accredited laboratory in the presence of KE Engineer, as per latest IEC Publications of IEC-60076 and its relevant/applicable parts on various tests. The total cost of such tests along with full expenditure of K-ELECTRIC engineer(s) alongwith Third Party inspector for witnessing these tests has to be borne by the Supplier/Contractor. The latest issues of Recommendations Recommendations of the international Electrotechnical Electrotechnical Commission (IEC) in particular the IEC 60076,IEC 60137, IEC 60214, IEC 60296 and IEC 60354 shall apply. For applicable technical standards, tests and general requirements refer to applicable sections of these Specification Documents. 5. EQUIPMENT IDENTIFICATION AND COLOR CODES
The color of the transformers shall be RAL7035 and shall be painted to C4 specification for 5-15years. 5-15years. 6. TECHNICAL DESCRIPTION 6.1
General Design
The design of the power transformers shall be based on the following requirements: a)
The transformers shall be designed for operation at ambient shade temperatures up to a maximum of 50oC.
b)
The maximum permissible temperature rise of the transformer oil (top oil) shall not exceed 45 K, the average temperature rise of the winding is to be limited to 50 K, and the winding hot spot temperature rise shall not exceed 63 K. The hot spot factor (H) for power transformers with core form type of core shall be 1.3.
c)
The transformers shall be capable of operating continuously within the specified temperature rise limits at their full rated power (full nameplate ratings) at all tap changer settings and under all specified site and installation conditions.
d)
The transformers, completely assembled with bushings, cable boxes and/or flange connections, shall be designed and constructed to withstand without damages the effects of short circuits as per IEC 60076-5 for at least 3 seconds after long-time emergency cyclic loading conditions as specified in IEC 60354 at 30 oC ambient temperature under thermal steady state conditions (to be verified by thermal short-circuit calculation and steady state heat-run test).
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e)
The transformers shall be designed with particular attention to the suppression of harmonic voltages to eliminate wave form distortion and from any possibility of high frequency disturbances reaching such a magnitude to cause interference with communication circuits.
f)
Neutral points shall be brought out and grounded as specified.
g)
The open delta of stabilising winding, if any, shall be brought b rought out by outdoor bushings and shall be shortened and grounded by solid copper bars rigidly supported and fastened.
h)
Provision for installation/adaptation of Sergi system to be made at transformer necessary drawing to be submitted by supplier for approval.
i)
Furthermore, each transformer transformer shall comply with the stipulations of the following Articles.
6.2
Windings
All transformer windings for LI: 650 kV / AC: 275 kV and below shall have uniform insulation. Transformer windings designed for higher insulation levels may have non-uniform insulation. In these cases the rated insulation level for neutral points shall be LI: 650 kV / AC: 275 k, Vector group is YNyn0 (d11). Due to the possibility of high transferred over-voltages LV windings with a rated voltage of 12 kV in power transformers having HV windings of Um= 110 kV and above shall be designed for not less than LI: 125 kV / AC: 50 kV, and the same in transformers not having HV windings of U m= 110 kV and above shall be designed for a rated insulation level of not less than LI: 95 kV / AC: 38 kV. Particular values for all insulation and test levels shall be obtained from the description of the Scope of Work / Scope of Supply and the Specific Works Data Sheets of these Specifications. All windings and their leads shall be designed and arranged such as to withstand all kinds of transferred overvoltages. Protective capacitors shall not be provided for any of the windings. Non-linear ZnO protective elements in any windings other than regulation windings will not be accepted. Windings shall be of best modern design with conductors having constant cross-section along the whole windings, and the current densities shall not exceed 2.62 A/mm2 in any part of the windings. Electrolytic copper of a high conductivity and insulation material of high quality (class A, in accordance with IEC 60085) shall be used. The insulation material of windings and connections shall be free from insulation compounds subject to softening, shrinking or collapsing during service. Moreover, none of the material used shall disintegrate, carbonise or become brittle under the action of hot oil, under all specified load conditions. The coils must be capable of withstanding movement and distortion caused by all operating conditions as specified in IEC 60354. Adequate barriers shall be provided between windings and core and between the windings. All leads or bars from the windings to the terminal boxes and bushings shall be rigidly supported. Stresses on coils and connections must be avoided. To increase the capability of the transformers of withstanding the stresses under short-circuit conditions modern technology in design and construction shall be applied (e.g. low current densities as above, and pre-drying and pre-compressing of the windings before mounting onto the core, etc.). The values for impedance voltages on extreme tappings shall not deviate from those for principal tappings by a percentage value of more than two third of the difference in percentage tapping factor between the concerned tappings and the principal tappings, and the transformers shall have the highest losses at the highest current taps (lowest voltage taps). At the time of inspection, FAT supplier would need to provide the certificate of origin/supplies origin/supplies of copper used in windings.
TECHNICAL SPECIFICATION POWER TRANSFORMER Specification No.
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Magnetic Core
The magnetic core shall be made of laminations of non-ageing, non-ageing, cold-rolled, grain-oriented, silicon steel of high permeability (Hi-B-type; W17/50: max. 1.05 W/kg) without burrs. The maximum magnetic flux density in the legs and yokes of the core shall not exceed 1.6 Tesla at rated r ated voltage and frequency. Each lamination shall be insulated with high quality insulation coating. The joints of limbs and yokes shall be designed and constructed to keep the no-load losses and the hot spot temperature in the magnetic core as well as the noise level as low as possible by application of the step-lap core stacking method. The core and its clamping plates shall form a rigid unit structure, which shall maintain its form and position under the severe stresses encountered during shipment, installation and short circuits. Care shall also be taken to secure uniformly distributed mechanical pressure over all the laminations to prevent setting of the core and to limit noise and vibrations to a minimum under service conditions. In order to prevent closed magnetic circuit via the tank, the top main core clamping structure shall not be connected to the tank cover. The magnetic core shall be earthed to the tank cover at one point only through removable links in an appropriate terminal box, placed in an accessible position on the tank cover and which, by disconnection, will enable the insulation between the core and transformer tank, etc., to be tested at voltages up to 2.5 kV for the purpose of checking deterioration during service. Magnetic circuits with an insulated sectional construction shall be provided with a separate link for each individual section. Where oil ducts or insulating barriers parallel to the plane of the laminations divide the magnetic circuit into two or more electrically separate parts, the ducts or barriers shall be bridged and the magnetic circuit shall not be regarded as being of sectional construction. The main earthing connection shall have a cross-sectional area of not less than 80 mm2 but connections inserted between laminations may have cross-sectional area reduced to a minimum of 20 mm 2. 6.4
Transformer Tank
The transformer tank shall be of the upper flange type with reinforced cover. The completely assembled tank including radiators, conservators, and associated oil piping shall be fully vacuum proof. The construction shall be of mild steel and shall be of sufficient strength and rigidity to withstand moving, shipping and handling without any de-formation. All seams and joints other than those of such tank covers, which may be jointed to the upper flange of the tank by welding, shall be welded both inside and outside of the tank to secure strong, leak-proof joints. The construction shall employ weldable structural steel of an approved grade to BS 7613 and BS EN 10029 or equivalent. The minimum thickness of tank walls shall be 6 mm for transformer lengths of less than 2500 mm and 9 mm for transformer length le ngth of 2500 mm and above, and that for tank cover shall s hall be at least 20 mm for transformers trans formers up to 80 MVA per unit and not less than 25 mm for transformers of 100 MVA per unit and above. Any kind of laminated tank covers are not acceptable. The tank bottom shall be of one plane and shall be a heavy rigid base structure. The four tank walls shall be plane and of one piece each and shall be welded directly onto the tank bottom without steps. Any kind of bell-type tanks are not acceptable. If heavy steel cross beams are provided as a rigid base structure the thickness of tank bottom shall not be less than 12 mm. In case of self-supporting tank bottom without heavy steel cross beams the bottom plate shall
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have a minimum thickness of 25 mm for transformers up to 30 MVA per unit, min. 30 mm for transformers up to 63 MVA per unit, min. 40 mm for transformers up to 100 MVA per unit and at least 50 mm for transformers above 100 MVA per unit. Laminated tank bottom will not be accepted. The completely assembled transformer shall be oil and gas tight and shall be capable of withstanding without damage, under service conditions, the forces arising under pressure conditions of at least 1.0 bar (>14 PSI) and/or exceeding 25% over the maximum operating pressure, resulting from the system of oil preservation used (whatever is higher). Tank stiffeners shall be provided as required, and these shall be designed to avoid water penetration. The complete tank and its cover shall be designed in such a manner as to leave no external pockets in which water can accumulate no internal pockets in which oil can remain when draining the tank and/or in which air can be trapped when filling the tank. Wherever possible, the transformer tank and its accessories shall be designed without pockets wherein gas may collect. For this purpose the tank cover shall be especially designed. Where pockets cannot be avoided, pipes shall be provided to vent any gas into the main expansion pipe. Vent pipes shall have minimum inside diameter of 25 mm. Both ends of the tank cover shall be connected to the main expansion pipe. All connections bolted to the tank shall be fitted with suitable gas and oil resistant gaskets made of such a material that no serious deterioration occurs under service conditions & must be heat and oil resistant rubber. All gaskets shall be of closed design (without open ends) and shall be of one piece only. Rubber gaskets used for flange connections of the various oil compartments shall be laid in grooves or in groove-equivalent retainers on both sides of the gaskets throughout their total length. Care shall be taken to secure uniformly distributed mechanica mechanicall pressure over the gaskets and retainers throughout the total length. Gaskets of neoprene and/or such material which can be easily damaged by over-pressing (e.g. any kind of impregnated/bonded or other kind of cork) are not acceptable for any of the equipment. Use of hemp as gasket material is also prohibited. Power transformers shall be equipped with manholes and hand-holes of suitable size to facilitate installation and maintenance (i.e. tap changers, current transformers, bushings etc.). Manholes for tap changers shall have size of minimum 800 mm in height and 350 mm in width, and shall be arranged in a convenient floor height. All openings in the cover of the transformer tank for bushings, manholes and terminal boxes shall be provided with adequate flanges. Covers for inspection openings, hand-holes etc. located on the tank cover shall be provided with adequate gas stoppers. Tap selector shall be equipped with one inspection window for observation. All inspection covers etc. shall be provided with two lifting handles each. It must be possible to remove any bushing completely without removing the tank cover. Easy access shall be also provided for internal connection of bushings without extensive dismantling any external mounting such as radiators etc. The tank cover and all covers for mounting, cleaning, manholes, handholes and inspection openings on tank and cable boxes etc. shall be earthed by suitable grounding conductors of the flexible type having a cross section of minimum 95 mm 2. Appropriate earthing studs with bolts and washers of stainless steel shall be provided. In order to prevent tank deformation during operation, spring-loaded pressure relief devices / explosion vents with trip contact of an approved type shall be mounted through approved elbow turrets onto the tank cover
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for rapid release of any pressure that might be generated within the tank and cause damage to the equipment. The devices shall operate at a static pressure which shall be less than the test pressure on tank. The nominal operating pressure of the devices shall not exceed 0.7 bar (or 10 PSI). The related elbow turrets shall be connected through vent pipes as above to Buchholz relay. All transformer tanks and radiators with fins shall be subject to oil leak tests as specified in the relevant Articles for Inspections and Tests. The following moving and handling facilities shall be provided for each transformer: a)
4 (four) jacking lugs for raising or lowering the transformers (completely filled with oil) by means of hydraulic jacks.
b)
Lugs for lifting the complete transformer. The minimum length of the base of the lugs shall be 300 mm for transformers of a weight up to and including 10 tons, and 500 mm for transformers of a weight above 10 tons.
c)
Eyes for lifting the core, coils, tank and/or tank cover.
d)
Pulling eyes for moving the transform tr ansformers ers in any direction.
e)
Bi-directional wheels with blocking facilities for transformers up to 125 MVA per unit. The distance between the centres of wheels shall be 1746 mm (Standard Railway guage).
f)
1 (one) tank access ladder of zinc-powder coated mild steel with lockable hinged door securely fixed onto the tank cover and lower parts of the tank (applicable for transformers with ratings of 20 MVA and above). Ladders shall be provided with hand-rails of min. 100 cm length at the upper end. Handrails shall be rigidly fixed on the ladders and onto the transformer tank. If the distance between the ladder and tank cover exceeds 4 cm an appropriate platform (e.g. grating securely fixed in a rigid mounting frame) with hand-rails as specified above shall be provided. Surface preparation and painting in accordance with relevant article of these Specifications.
g)
Filter valves of the slide valve type for oil inlet and outlet arranged diagonally on lower part of tank. A suitable valve for vacuum application shall also be provided in a convenient floor height. All of these valves shall have minimum 50 mm inside diameter and shall be equipped with flanges having adapters with R 1 ½" male thread fitted with screwed cap.
h)
Oil sampling valves (top and bottom) with suitable adapters of R ¾" male thread fitted with screwed cap for direct connection of oil sampling facilities shall be provided and shall be arranged diagonally on one tank wall at a convenient floor height.
i)
Padlocking facilities for all valves including radiator butterfly valves.
j)
Two adequate earthing terminals completely made of stainless steel capable of carrying for 5 seconds the full lower voltage short circuit current of the t he transformer shall be provided and installed diagonally at the bottom of the transformer tank.
6.5
Terminals
a)
Out door Bushings
Where specified, outdoor bushings shall be provided. Uncovered bushings other than those to be solidly grounded shall be designed for pollution level “IV” (very heavy) in accordance with IEC 60815, unless
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specified otherwise in the Specific Works Data Sheets. They shall correspond to IEC 60137, shall be free from defects and shall be thoroughly thorou ghly vitrified. vitr ified. KE requires Trench (France (France make) make) or Passoni Passoni Villa (Italy (Italy make) make) Bushings, for any other manufacturer prior approval will be required by contractor. Insulators shall be of top quality electrical grade porcelain, homogenous and non-porous, and shall be in one piece. If insulators are composed of several parts jointed together by synthetic resin, this shall be brought to the attention of K-ELECTRIC. The glaze shall not be depended upon for insulation and shall be of a uniform shade of brown, completely covering all exposed parts of the insulator. Bushings for power windings of Um= 72.5 kV and above shall be of the condenser type equipped with test tap at the bushing flange. Bushings for windings below Um= 72.5 kV shall be preferably oil-filled as per DIN standard or equivalent equipped with rigidly fixed solid gas stoppers. DIN equivalent bushings for power windings of rated voltage: 33 kV and above shall be provided with metallised lower part. All bushing connecting nuts, bolts, washers, rings, caps on the top shall be of non-magnetic non-magnetic material. Each condenser bushing shall have marked upon it, the manufacturers name or identification mark and year of manufacture as well as serial number. These marks shall be clearly legible and visible after assembly of fittings and shall be imprinted and not impressed. All bushings shall be designed for operation and storage in a horizontal position without any restriction. All bushings shall be designed for the highest over-current that can flow through the windings. The bushings shall be arranged on the tank cover in such a manner, that removal of the same is possible without lowering of the oil to such a level where the windings are exposed to the atmosphere. atmosphere. Bushings up to Um= 52 kV shall be arranged in an upright position. Bushing turrets with removable flanged-on covers on the bushing side shall be provided for all bushings. Removable bushing turrets bolted onto appropriate flanges on the tank cover are also acceptable. Common bushing turrets of an approved design may be provided for bushings up t o Um= 52 kV. Common bushing turrets shall be provided with two vent plugs each to be arranged at an approved location. Removable bushing turrets shall be provided with four adequate lifting lugs each. All bushing turrets shall be equipped with vent pipes on their highest points which shall be connected to main expansion pipe to route any gas collection through Buchholz relay. Easy access shall be provided for internal connection of bushings without extensive dismantling any external mounting such as radiators etc.
b)
Cable Termination Boxes
Where specified air insulated terminal boxes on the LV side shall be provided suitable for the connection by busduct(s). The transformer Tenderer/Contractor shall co-ordinate with the bus-duct Tenderer/Contractor for the requirements of the mechanical and electrical transition from the bus-duct to the transformer transformer termination box. As far as the bus-duct connection is concerned the scope of supply/works for the transformer Tenderer/Contractor shall be limited to the termination box incorporated with suitable flanges and gaskets (as determined by the bus-duct Tenderer/Contractor) Tenderer/Contractor) and the terminals of the bushings including
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bus-bars, if required. Suitable grounding studs with bolts and washers made of stainless steel shall be provided as determined by the bus-duct Tenderer/Contractor. The supply of the bus-duct Tenderer/Contractor shall include the transition from bus-duct housing to transformer terminal box and the electrical connections (by braided links) between the bus-duct conductors and the transformer bushings. The bus-duct(s), neither their housing nor their electrical connections, shall exert any forces on the terminal box or the bushings of the transformer. The terminal box shall accommodate outdoor bushings as above, and the design shall comply with protection category IP55. Access openings shall be foreseen for checking of the bushings as well as for making and checking of the electrical connections. Ingress of dust and formation of condensate in the termination boxes must be prevented by two parallel silica gel breathers of min. 2 kg silica gel filling capacity controlled by two-position three-way valves as specified in Article below. c)
General
All bushings shall be at least of the same insulation level as that for the related windings and/or neutral. For all terminals of windings undergoing switching impulse tests the clearances in air between life parts shall exceed those specified in IEC 60076-3 by at least 5 percent. Each of the bushings shall be designed for a rated current corresponding at least to the current for longtime emergency cyclic loading of the transformers as specified in IEC 60354. Support insulators shall be of top quality electrical grade porcelain or cast resin and shall be of a uniform shade of brown. Insulators shall have the same minimum creepage distances as the related r elated bushings, and the creepage distances of cable sealing ends shall be co-ordinated accordingly. All main flange connections, cable boxes and related covers etc. shall be earthed by suitable grounding conductors of the flexible type each having a cross section of minimum 95 mm2 or as per detail design of the earthing system. In case of different Tenderer/Contractor for transformers and HV connections etc. all parties are to cooperate in order to ensure a proper and complete boundary between these sectors, i.e. the Tenderer/Contractor Tenderer/Contractor for transformers transformers shall provide the specified bushings and/or connection boxes and all connection parts at the transformer transformer side and/or the complete sealed cable terminating boxes including the stress cones and all parts for proper connection of the sealing ends, and suitable flanges with oil-/SF6bushings (double-flange bushings) for GIS-type surge arresters, if required. On the other hand, the Tenderer/Contractor Tenderer/Contractor for cables, switchgear and all other connections shall provide the complete pot heads and cable sealing ends, bus-duct and/or SF6 connection boxes including i ncluding metallic bellows (if required), surge arresters, adapter pieces and all other equipment required for proper completion and function of the related work. It is hereby understood that responsibility of the transformer Tenderer/Contractor covers the oiltightness. 6.6
Current Transformers
Where required, current transformers shall be provided in accordance with the requirements of these Specifications. Specifications. They shall be installed in suitable bushing turrets turret s as specified above, and shall be arranged
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and connected in such a manner that easy removal of the same is possible without cutting or removal of any insulation material of the leads to the bushings required and without lowering of the oil to such a level where the windings wi ndings are exposed to the atmosphere. All of the concerned bushing turrets shall be equipped with appropriate current transformer termination termination boxes for direct connection of the related CTs. Separate termination boxes shall be provided for current transformers for protection and those for used for thermal replica. The technical data shall also be co-ordinated with the protection requirements and the related switchgear CTs. If the requirements of protection show that a higher rated output and/or ratio than specified is necessary, the Tenderer/Contractors shall provide the current transformers for the required ratings without extra price. Reference is made to the relevant Articles for protection relay and stability with regard to current transformer's design. The Specifcations of the current transformers transformers including excitation curves shall be submitted with the offer to K-ELECTRIC for approval. All current transformers shall be designed for an extended rated current of at least 150% to cover cyclic loading duties as per IEC 60354. Where built-in current transformers are provided, the related bushings, SF6 connection boxes and cable terminal boxes shall be arranged to be removed without interfering with the pertinent current transformer. Removal of any CT must be possible without lowering of the oil to such a level where the windings are exposed to the atmosphere. 6.7 a)
Cooling ONAN Cooled Transformers
Transformers of a rated power up to 15 MVA per unit shall be provided with a self-cooled type of cooling system (ONAN) provided by at least two groups of detachable radiators flanged directly onto the tank and/or external headers at the transformer tank, mainly in the vicinity of the core-/coil-arrangement at the two along sides of the transformer. Radiators shall be of the DIN type or equivalent provided with six cooling channels in each radiator fin. Accumulation of air in the radiator heads must be avoided. Radiators of the multi-tube type or similar arrangements are not acceptable. The cooling fins of the radiators shall have nominal width of 470 - 520 mm, and their height shall not exceed 3.0 m. The nominal sheet steel thickness t hickness of the radiator walls shall be not less than 1.2 mm. The radiator fins shall be welded with approved stiffening rods (horizontally and diagonally) to prevent vibration during operation of the transformers. transformers. The distance between horizontally arranged bracing straps shall not exceed 100 cm. Radiators shall be fully vacuum proof and pressure tested and shall be liquid tight. The radiators shall be fitted with suitable drain and vent plugs so that they can be completely drained and vented. No radiators shall be fitted underneath of air-filled cable boxes. The radiators shall be connected to the tank or external headers by butterfly valves in such a manner that each radiator can be removed without taking the transformer out of service, and without draining any oil from the tank and/or common headers (if any). The mechanical tolerance of the arrangement shall be minimised to allow the exchange of all radiators of the same type without additional fitting. The lower radiator headers shall be connected to the transformer tank or common headers in a height of not less than 80 cm above floor level.
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All butterfly valves shall be arranged in a vertical position and in such a manner that their position indications are clearly and freely visible and legible directly from tank cover and from ground level. Valve position indicators must not be arranged underneath the flange of the t he tank cover. Flanged on common headers, if any shall be connected each to the tank via slide valves mounted directly onto the transformer tank or cover. Common headers shall not be connected to bushing turrets. Accumulation of air within the radiators and headers must be avoided. Upper common headers for connection of radiators shall be connected through isolation valves and vent pipes to the main expansion pipe. Radiator banks mounted onto the tank or separately shall not be provided. The radiators shall be assembled and fitted to the tank in such a manner as to provide mechanical protection to themselves and to prevent vibrations. Suitable stiffening bars of stainless steel shall be fitted along the radiators on top and bottom. Stiffening bars shall not be arranged cross-wise on top and bottom of the radiator groups. All parts of the equipment shall be accessible for inspection and cleaning. Hot-dip galvanised radiators shall not be provided. Where applicable, the following accessories shall be provided:
1 (one) butterfly valve each for inlet and outlet for each radiator, directly accessible from ground level and tank cover
2 (two) isolation valves for connecting of each common header (if any) with the transformer tank and/or cover
1 (one) drain plug with screwed cap at the outlets of each lower common header (min. two lower common headers, if provided) suitable for temporary installation of temperature sensors directly in the oil-flow during heat-run tests
1 (one) air vent plug with screwed cap at the inlets of each upper common header header (min. two air for upper common headers, if provided) suitable for temporary installation of temperature sensors directly in the oil-flow during heat-run tests
Additional air vent plugs and drain plugs on common headers, as required
1 (one) drain plug for each radiator at the outlet of each radiator suitable for temporary installation of temperature sensors directly in the oil-flow during heat-run tests in case of radiators directly flanged onto the tank
1 (one) air vent plugs each at the inlet of each radiator header suitable for temporary installation of temperature sensors directly in the oil-flow during heat-run tests in case of radiators directly flanged onto the tank. For radiators with upper headers of the elbow type ("swan-neck" type) air release plugs shall be provided at both ends of these headers
Numbered identification plates for all butterfly valves and other valves, so as to comply with the plate for valve arrangement and piping. Particular details for all plates are specified below.
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ONAN / ONAF Cooled Transformers
Transformers with a rated power above 15 MVA and up to 250 MVA per unit shall be equipped with a self cooled / forced air cooled type of cooling (ONAN / ONAF). Unless specified otherwise in the Specific Works Data Sheets, the self cooled capacity (ONAN) shall be at least 75% of the forced cooled rating. The ONAN cooling capacity shall be provided in accordance accordance with all applicable requirements as specified, but by means of three separately mounted banks of detachable radiators as above arranged in three closed rows of three equal groups in a distance of not less than 1.5 m from each other and flanged on to common headers by butterfly valves in such a manner that each radiator can be removed without draining any oil from the tank and headers. The height of the individual radiators shall not exceed 3.5 m. Accumulation of air within the headers must be avoided. The radiator banks shall be assembled and fitted to the and in such a manner as to provide mechanical protection to themselves and to prevent vibrations as specified. Approved expansion pieces shall be provided in each oil pipe connection between the transformer and each cooler bank. Appropriate supporting structure shall be provided at both ends of each cooler bank as a minimum requirement.
The upper common headers of each of the cooler banks shall be connected directly to the tank cover at three points. Additional common headers shall not be provided. The upper common headers connected to the tank cover shall also be provided with by-pass vent pipes to main expansion pipe(s) to route any gas collection to Buchholz relay when the related shut-off valves are closed. Upper common headers must not be connected to bushing turrets and/or to the centre of the tank cover. Upper common headers shall be connected through vent pipes to the main expansion pipe. Vent pipes other than by-pass vent pipes for isolation valves from upper common headers to Buchholz relay shall be provided with shutoff/isolating valves each on header side to avoid back-flow from conservators when the cooler bank is under maintenance. maintenance. The lower common headers shall be installed in a height of not less than 1.8 m and not exceeding 2.1 m above floor level. Lower common headers in addition to those coming from the individual radiator banks shall not be provided. The ONAF cooling shall be provided by means of single phase fan units mounted underneath the radiators in such a manner as to avoid any hot air circulation when the transformer is installed in the transformer bay. Fans must be provided from well reputed and at least 20 years experienced manufacturer. Prior approval must be taken from KE engineer for the manufacturer of fan. Minimum two more fans than required for continuous operation of full rated power within specified temperature rise limits shall be included and shall be completely wired up to the starter.
The fan units shall be fitted in an accessible position in a height of not less than 100 cm onto suitable noncorrosive steel structure/framework, structure/framework, which shall be bolted rigidly onto the radiator groups. The fan units attached to radiators shall be mounted in a height not exceeding 2.0 m above floor level. The fan units shall be arranged in such a manner as not to protrude beyond the fins of maximum one pair of radiators. The overall diameter of the fan units shall not exceed 85 cm. Overlapped arrangement arrangement of the fans with any fan(s) of other radiators must be avoided. Each fan unit shall be individually removable without dismantling of any structure and without having to interfere with the operation of other fans. No fan units shall be attached to radiators arranged underneath the air-filled cable boxes.
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The propellers shall be made of sea-water proof aluminium alloy or stainless steel. Propellers made of any kind of plastics are not acceptable. Mechanical protection against touching of the fan blades shall be provided by galvanised round wire mesh guards on both sides of the fan blades. The fan motors shall be arranged at an easily accessible position, and their terminal boxes shall be accessible without removing the guard. A nameplate made of stainless steel of top quality for each fan motor shall be provided clearly visible and legible on the outer housing of each fan unit at an accessible position. Starting from the hot condition (100% load at rated excitation) the transformer shall be capable of remaining in operation without exceeding hot spot temperature (windings) of 125 oC at specified maximum ambient temperature after failure of forced cooling for not less than 60 minutes after outage of all forced cooling. The control equipment for the cooling plant and all auxiliary devices shall be accommodated in a weatherproof cabinet (protection class IP55W) mounted onto the transformer. 6.8
Control of Cooling Units
The electrical supply for the control of the cooling units and for motor drive of OLTC shall be provided by means of two independent feeders protected by circuit breakers installed in the fan control cabinet and/or marshalling box as specified. To cover the event of an electrical supply failure, automatic switchover from the first feeder to the second feeder is required. Automatic transfer equipment shall include a time delay relay to prevent immediate transfer from normal to emergency emergency source. Circuit breakers shall be installed for manual switching of each cooling group. Fuses will not be accepted. a)
ONAN / ONAF Cooling
The fan motors or groups of motors shall be automatically controlled by a relay combination taking into consideration the winding and oil temperature. The criteria for automatic "on/off" switching operations shall be the winding temperature (ON) and the oil temperature (OFF), respectively. Control shall be such that frequent start/stop operation for small temperature differences must be avoided. A time delay relay shall be provided to prevent switching "off" the fans for at least five minutes after starting of the same. The fan motors shall be connected to the starting contactors by groups. The first group shall come into operation at lower temperature (i.e. at 75oC hot spot temperature) and next group(s) at higher temperature (i.e. at 85oC hot spot temperature). The control shall be such that, if the first group fails to come into operation on winding temperature reaching the set value on the contacts of winding temperature indicator, next group(s) when it comes into operation, consequently to winding temperature reaching higher set value, shall bring the first group of fans also into operation. The fan groups shall not switch "off" on winding temperature falling to values set on winding temperature indicator for switching "on" of the groups, but they shall switch "off" when the top oil temperature falls below set values to switch "off" the groups. That is, the starting impulse for th e groups shall be given by the winding temperature indicators and stopping impulse by the contacts of the top oil temperature indicator. All motor contactors and their associated apparatus shall be designed for the specified control voltage and shall be capable of holding in and operating satisfactorily and without over-heating for a period of ten
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minutes if the supply voltage falls for that period to 85% of normal control voltage. Auxiliary transformers for control voltage shall not be provided. The contactors shall be protected by means of thermal and magnetising tripping elements. However, motor protection switches with adjustable setting range (approx. 120 - 150% of rated motor current) are to be provided for each of the fan motors. A group alarm shall be initiated if any fan fails, however, switching off of any further motor of the t he same group must be avoided. Electrical isolation of motor circuits shall be provided to facilitate replacement or repair of individual units during operation of the others. Voltage relays of the three-phase type shall be installed for supervision of the voltage supply circuits. Change-over-switches with three positions, i.e. for automatic, off and manual control, shall be provided for each of the fan groups. The following alarm initiating devices having N.O. contacts shall be provided:
Auxiliary supply - auto change-over
Cooling fan's failure for each fan group.
The following signal initiating devices having N.O. contacts shall be included:
Cooling fans start for each fan group
Cooling system on automatic control
Cooling system on manual control.
7. TAP CHANGERS
a)
On-load Tap Changers
Where required, on-load tap changers (OLTC), as per specifications, for manual control and electrical remote control shall be provided. The OLTC shall be based on the principle "Dr. Jansen", comprising a tap selector with change-over switch and a rotary type diverter switch of high speed transition resistor type, and their transition contacts shall be made of copper-tungsten. OLTC of only MR Germany make is acceptable. For windings up to Um= 52 kV (up to 170 kV is acceptable only if all the other particular requirements of the tender specifications are fulfilled accordingly) the two-vacuum-switch principle or the on-load tap selector switch principle with transition contacts made of copper tungsten is also acceptable provided that all other particular requirements of the Specifications Specifications are fulfilled. The OLTC shall be in conformity with IEC 60214 and IEC 60542. OLTC shall have been type tested by a recognised independent testing authority. Only designs which have been type tested in accordance with the relevant IEC standards will be accepted. All equipment related to the OLTC shall be supplied by the original OLTC manufacturer. manufacturer. This is also applicable for tie-in resistors, resistors, if provided. Licence products etc. are not acceptable. The OLTC shall withstand all kinds of through-fault currents without damage. In all cases of delta connected windings for Um= 36 kV and above the OLTC shall be provided in mid-winding arrangement exclusively. All OLTC connected to uniformly insulated windings shall have at least same LI and AC voltage withstand levels as the related windings. For all applications where OLTC are connected directly to line
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terminals of any of the windings , they shall be insulated for minimum one basic lightning impulse withstand level higher than that as specified for the related line terminals. The power of the transformers shall remain constant at all tap positions, and the OLTC shall be capable of successful tap changes for the maximum current to which the transformer can be loaded. The OLTC shall be designed for rated through currents of not less than 350 A, and the permissible continuous throughcurrent of each tap changer unit at rated switching capacity shall cover all cyclic loading duties as per IEC 60354 at highest current tap and at rated system operation voltage applied on the transformer terminals. Any parallel connection of tap changers is not acceptable. acceptable. In case of tie-in resistors being provided they shall be connected via potential switches to the take-off terminal of the tap changer so that power dissipation only occurs during the short potential switch operation time, and these resistors shall be designed under consideration of 10 (ten) percent overexcitation applied to the transformer. Any resistors being of graphite elements will not be accepted. In case of any non-linear protective elements and/or tie-in resistors being provided, this shall be indicated in the connection diagram as per relevant Article. The OLTC(s) shall be mounted from the cover into the transformer at narrow side(s) of the tank. Tap changers related to the same winding shall be arranged at the same end of the tank. Metal covers for drive shafts shall be provided on tank cover. The diverter switches and/or selector / vacuum switches shall have oil compartments separate separate from the transformer oil as well as their own closed sub-sections in the oil conservator. conservator. Each diverter or selector switch shall be equipped with an internal suction pipe led to the ground of the compartment and to be connected to an external drain, filter and sampling valve mounted at a convenient floor height. The tap changer head shall be equipped with a bleeding duct to be connected to Buchholz relay of main tank to avoid any gas collection underneath the tap changer head outside the switching compartments. No piping or other equipment shall be arranged beyond the tap changer head to allow lifting of the diverter switches and/or selector (vacuum) switches without any restriction and without removing (dismantling) of any other equipment. An oil-flow operated protection relay shall be provided for internal failure protection. This oil-flow relay shall be provided on elbow pipe on tap changer head and shall have slide valve on side of piping to OLTC conservator. In addition a spring-loaded pressure relief device with trip contact and pin-type operation indicator shall be mounted directly onto the tap changer head. The motor drive, plus all auxiliary equipment for operation of the tap changer, shall be incorporated in a rigid control cabinet, protection class IP56 or better, and shall be mounted onto the transformer tank in a convenient floor height. The driving gear shall be of the belt-type or equivalent dry-type gear. Oil filled driving gears are not acceptable. The protection housing shall be of min. 4 mm thick aluminium alloy and shall be of an extra large size to prevent impermissible heat and to allow accommodation of especially supplementary equipment. Cleaning and surface preparation of the equipment shall be in accordance with relevant Article of these Specifications. Specifications. However one primer coat may be omitted for aluminium. In case of swing-frames being installed in the cabinet the hinges of the outer door shall be arranged on the side opposite to those t hose of the swing-frames.
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The complete wiring shall be of highly flexible stranded copper and furnished with slip-over ferrules at both ends. Wiring shall also have crimped termination. The minimum cross section of the wiring other than for step position transmitters shall be 2.5 mm2. The AC supply of the motor drive cabinet shall occur via the control cabinet for cooling equipment or marshalling box, and an appropriate MCB with trip contact shall be provided in the concerned cabinet for the outgoing auxiliary supply cable. The instrument compartment shall be of protection category IP56. Sight glasses shall be of sand-storm proof laminated security glass. No sight glasses of transparent plastics shall be provided. The cabinet shall be mounted on a narrow side of the transformer and the following main equipment shall be installed:
Driving motor with adjustable motor protection equipment (setting range: approx. 120% - 150% of rated motor current)
Main switch for emergency stop (load break switch min. 40 A)
Operation counter
Control switch or push buttons for local raise/lower operations operations (inside of the cabinet)
All electrical control switches and local manual operating gear shall be clearly labelled in an approved manner to indicate the direction of tap changing, i.e. raise and lower tap operation
Electrical limit switches
Mechanical stops in end positions
Step position indicator with engraved position numbers, easily legible from ground floor ("1" related to the position with the maximum high voltage, all windings in circuit)
Local/remote switch
Voltage supervisory relays for phases of supply voltage and main circuits of control voltage
MCBs for each auxiliary supply circuit
Hand lamp (controlled via door contact)
One permanent heater
One heater, thermostatically controlled
Min. two conventional position transmitter of the resistor type
One additional position transmitter of the resistor type with tap position transducer, output: 4-20 mA, with individual MCB being provided in the motor drive cubicle
Min. two conventional position transmitter of the contact type
One additional contact type position transmitter with diode-matrix for digital remote position indication
Additional end position contacts
Spare plug (standard universal socket)
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Terminal blocks with terminals of single insertion type with isolating facilities and test connectors and being universally suitable for connection of solid conductors from 1 mm 2 up to a cross-section of at least 6 mm 2, with ten percent spare terminals
A metal plate showing the control circuits and all terminal blocks to be rigidly fixed directly onto the inner side of the front door
Crank handle for manual operation
Padlock facilities for front door.
All equipment installed in the cabinet shall be designed for a cubicle inside temperature of at least 70oC. A rigid pocket for storing the concerned circuit diagram shall be securely fixed on the inner side of the front door, besides plates showing the control circuits and terminal blocks. The requirements to be met by the motor drive are summarised below:
Mechanical indication of step position at the motor drive cabinet
Transmission of step positions of the transformers to the load dispatch centre and to the local control room
Manual operation in the case of a failure in the electrical supply system
Push button remote operation via the local control room and/or via the load dispatch centre and remote tap position indication
Step-by-step operation with automatic stop after each step
No interference of the running tap changing procedure by permanent control switch/push button action
Operation from local or remote control switch shall cause one tap movement only unless the control switch is returned to the “off” position between succes sful operations
Automatic passage passage control for central taps
Automatic restart of tap changing operation after a failure in the electrical supply system, interlocking to be provided against simultaneous raise/lower operation
Blocking of end positions by means of limit switches
Protection to prevent over-running of any tap position
Provisions to be made for parallel running and automatic operation controlled by a voltage regulating device and parallel control unit
Motor operation via push buttons or lower-/raise-switch
Hand operation by means of a crank handle
It must not be possible to operate the electrical drive when the manual operating gear is in use.
All apparatus and instruments required for remote control as well as the connections and control cables running from the transformers towards the external and internal circuits of the substation are to be provided as specified in the Scope of Work / Scope of Supply.
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8. PARALLEL OPERATION AND VOLTAGE REGULATION
The power transformers of each station shall be able to be operated in parallel. Suitable automatic paralleling equipment shall be provided which can be operated by selector switches mounted on the transformer, control panel at the control room and via the load dispatch centre. The equipment required for automatic voltage regulation such as the voltage regulating relay, auxiliary relays, meters, switches, overload blocking facilities, signal lamps, test terminals and other accessories necessary for operation such as connections and control cables running from the transformer towards the external and internal circuits of the substation are to be provided as specified in the Scope of Work/ Scope of Supply. 9. PERFORMANCE CHARACTERISTICS OF MOTORS
a)
The motor shall be capable of giving rated output without reduction in the expected life span when operated continuously under the following supply conditions:
Variation of supply voltage from rated r ated motor voltage ±10%
Variation of frequency ±5%
Combined over- or under-excitation ±10%.
b)
The motor shall be suitable for full voltage direct on line starting.
c)
The motor shall be capable of starting and maintaining the load exceeding acceptable winding temperature when the supply voltage is in the range of 85% of the rated supply voltage.
d)
AC motors shall be of the three-phase squirrel-cage rotor type.
e)
Insulation shall be given tropical and fungicidal treatment suitable for hot, humid climate, and the protection category category of the motors shall be at least IP 55.
10. TRANSFORMER OIL
The insulation oil shall be new uninhibited naphtenic based mineral oil free from additives. It shall be acid-refined and pre-treated, and shall have properties complying with IEC 60296 - class II as well as with DIN 51554 with regard to Baader test values and ageing properties. However, the kinematics viscosity shall not exceed 9.0 mm2/s at 40oC, and the dielectric dissipation factor at 90oC shall not exceed 0.0025 after pre-treatment as above. Insulation oil used for all power transformers and shunt reactors to be delivered for the same substation shall be of the t he same oil manufacturer and type. Before utilisation the dryness (water content in ppm) and all other properties of the oil should be proved & indicated. The dissolved gases in oil and the dielectric strength of the insulation oil shall also be proved. 11. OIL CONSERVATOR C ONSERVATOR
Conservator vessels shall be provided in such a position as not to obstruct the electrical connections to the transformer and it shall have sufficient capacity to allow for oil expansion from 0 oC to 120oC. Conservator vessels shall be sealed against each other and shall not be located directly on (along) the tank cover.
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Main tank conservator vessels shall be of the cylindrical type and shall be equipped with elastic diaphragms of the air-bag type. They shall also be connected to the tank cover at the end opposite to OLTC. Magnetic type oil level indicators showing the full level range shall be fitted to all oil vessels, being clearly marked with the normal level. Tap changers shall have their own closed sub-sections in the conservator. To avoid unnecessary permanent stresses from switching compartment(s) of OLTC to that of the transformer main tank all conservator compartments shall be designed in such a manner that at the same oil temperature all oil levels are nearly equal, and the installation level of the conservator vessel(s) shall not exceed 3.5 m above tap changer head(s) to avoid impermissible stresses at any OLTC compartment when the diverter and/or selector switches are drawn out for maintenance. The conservator vessels shall be fully vacuum proof and designed in such a way that they can be completely drained by means of drain valves. Conservator vessels shall be furnished with cleaning openings in such a manner as to avoid damage of rubber diaphragms, i.e. the front walls of the conservators shall be completely removable removable and shall be equipped with two lifting lugs each. A vacuum application valve and vacuum equalising valves for diaphragm(s) and for OLTC conservator(s), shall be provided between the air-expansion pipes to the silica gel breathers. The vacuum application valve and the vacuum equalising valves between the conservators conservators and for diaphragms shall be rigidly fixed at a convenient floor height. Each conservator vessel shall be fitted with two parallel breathers in which only blue silica gel (Pink when wet) in accordance with the newest IEC regulations has been filled as a dehydrating agent. The containers for the dehydrating agent and the oil trap shall not be of transparent plastics. The parallel breathers shall be connected to the air-expansion air-expansion pipes via approved two-position three-way three-way valves with captive screwed caps. A universal spanner for removing of the cap and operation of the valve shall be fitted to the tank by a fly-nut on a rigidly fixed bolt of stainless steel at an accessible position in a convenient floor height. In view of excessive humidity breathers shall be larger in size and shall be provided with oil trap. The silica gel filling capacity of each breather shall be dependent on the size of the transformers (each having a minimum filling capacity of 3 kg for the OLTC conservators and 4.5 kg for transformers up to 30 MVA per unit, 5.5 kg for transformers up to 100 MVA per unit and minimum 7 kg for transformers above 100 MVA per unit shall be provided). The silica gel breathers as well as all filling and draining devices shall be rigidly fastened at an accessible position in a convenient floor height. Furthermore all of the breathers shall be rigidly fixed onto the tank by appropriate mounting brackets at their lower ends. 12. PIPING AND VALVES
Isolation valves shall be provided at the conservator to cut off the supply and to drain the conservator. All piping required for the connection/filling of the various parts of the transformers as well as the valves required for oil sampling, draining, draining, filtering, connection of the radiators, drain and vent v ent plugs, etc. are to be included. All flanges to which the valves are to be connected shall be welded leak-proof onto transformer tank and piping etc. All piping shall be rigidly supported. The inner diameter of vacuum application pipes and main expansion pipes to main conservator shall not be less than 50 mm and that for other piping other than small piping to Buchholz gas testing devices shall not be less than 25 mm. All
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piping on tank cover shall be provided with suitable flanges for removal for transport etc. Flexible oil-pipes are not acceptable. Two position three-way cocks of 25 mm inside diameter shall be provided to control the breathers in such a manner that any one of the two parallel breathers is in service while the other breather is in stand-by position. Any position other than specified previously shall be mechanically interlocked. All three-way valves shall have captive screwed caps. Combined spanners for removing the caps and operation of the valves shall be delivered as mandatory tools. All valves for draining, oil sampling, filling, filtering, vacuum application and vacuum equalising shall be mounted at a convenient floor height and shall be equipped with approved rigid padlocking facilities provided with padlocks for a master key system for each transformer. All isolation valves and shut-off valves other than butterfly valves for radiators shall be proper slide valves, i.e. globe and/or gate valves equipped with adequate operation handles and position indicators (“open”/“shut”). However ball -type valves with single-operation single-operation handles may be provided for oil-sampling valves on main tank and sampling valves on oil-filter units provided that the single-operation handles and their padlocking facilities are made of stainless steel with embossed position indication (“open”/“shut”). All filter valves shall have adapters with 1½" male thread fitted with screwed cap. All other drain and sampling valves shall have the same with ¾" male thread. In addition two suitable adapters 1½" and ¾" (including oil sampling hoses) for all types of oil-sampling and filter valves shall be delivered for each transformer as mandatory tools. 13. MEASURING AND MONITORING EQUIPMENT
The equipment of this item shall be wired up to terminal blocks inside the control kiosk. The complete wiring shall be of highly flexible stranded copper and shall be furnished with approved slip-over ferrules at both ends. All equipment installed in control and marshalling cabinets shall be designed for a cubicle inside temperature of at least 70oC. Thermometers and thermostats shall be provided with contact units adjustable to scale and easily accessible when removing the lid. All monitoring equipment arranged outside the cabinet(s) shall be of protection category IP55. Sight glasses of thermometers and oil level indicators shall be of sand-storm proof laminated security glass. No sight glasses of transparent plastics shall be provided for any of these indicators. Thermometers Thermometers shall be arranged in an approved manner under corrosion-proof covers close to the control kiosk. Capillaries shall be properly protected throughout the total length by flexible steel conduits. To avoid damages at the connection points of capillary tubes to temperature detectors all heads of these sensors shall be covered completely. Thermometer pockets shall be arranged in the vicinity nearest to the active part. The following standard accessories shall be provided for each power transformer unit: a)
1 (one) twin-float Buchholz relay for transformer tank with metal gas sampling and testing device (gas collector) with sight-glass, and to be operated from the ground at convenient floor height. The pipes connecting the Buchholz relay shall have slide valves on the conservator and tank side (easily accessible) to enable dismantling of the relay without oil leakage. Small piping from Buchholz relay
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to gas sampling and testing devices shall be covered throughout the total length by flexible steel conduits. b)
1 (one) twin-float Buchholz relay as before for the oil-filled cable terminal boxes of each winding commonly (in case of two cable boxes for neutrals: one common twin float Buchholz relay in addition).
c)
1 (one) single-float gas-detector gas-detector relay for each main conservator connected connected to the highest point of front wall of each main conservator as leakage detector for diaphragm.
d)
1 (one) protective relay (oil-flow operated) with trip contact for each OLTC. The pipes connecting the relay shall have slide valves on the conservator side (easily accessible from tank cover).
e)
1 (one) pressure relief device of spring-loaded type with pin-type operation indicator and trip contact for each OLTC.
f)
1 (one) pressure relief device of spring loaded type with pin-type operation indicator and trip contact for transformer main tank (for transformers above 63 MVA per unit two pressure relief valves arranged on opposite ends on the tank cover).
g)
1 (one) pressure relief device of spring loaded type with pin-type operation indicator and trip contact for each oil-filled cable box.
h)
1 (one) oil-flow monitor with alarm contacts for each cooling pump (forced-oil cooled transformers only).
i)
1 (one) dial type thermometer for top oil temperature with radial type main and maximum pointer, remote indicator, and four adjustable contacts for oil temperature alarm and trip (at 95oC and 105oC) and switching OFF the cooling groups (at 65 oC and 55oC). The range of temperature indication shall be from -20oC to 140oC. In addition, a signal conditioner with 4-20 mA output, with individual MCB, for remote temperature indication shall be provided.
j)
1 (one) thermal replica to be connected to each winding other than the stabilising winding via current transformer. These current transformers transformers shall be of class 1M, and the rated primary current shall correspond to the rated current of the related transformer winding. The effective resulting rated secondary current shall be 2 Amps. Matching units between current transformers and thermal replicas shall not be provided.
k)
1 (one) dial type thermometer with radial type maximum pointer and heating coil in thermometer thermometer pocket in tank cover for each thermal replica with remote indicator and four adjustable contacts for winding hot spot temperature alarm and trip (at 115oC and 130oC) and switching ON the cooling groups (at 75oC and 85oC). The range of temperature indication shall be from 0oC to 160oC. In addition, a signal conditioner with 4-20 mA output, with individual MCB, for remote temperature indication shall be provided.
l)
1 (one) magnetic type oil level l evel indicator with alarm contacts (minimum and maximum oil level) for each main conservator vessel (arranged sloped at the conservator).
m)
1 (one) magnetic type oil level indicator with alarm contacts (min. and max. oil level) for each conservator vessel of OLTC.
n)
1 (one) ammeter for checking the output of the current transformer of each thermal replica (also to be used during calibration).
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1 (one) Silica gel breather each for main tank and OLTC (self-regenerating type)
14. CONTROL CUBICLES, MARSHALLING BOXES, WIRING AND A ND CONDUITS
A rigid weather-proof control cabinet (protection class IP55) shall be provided for each transformer for the accommodation of electrical controls, as well as alarm and trip circuits of the measuring and monitoring equipment. Control circuits shall be protected by adequate miniature circuit breakers with alarm contacts, suitably wired and integrated in the overall alarm system of the station. Fuses will not be accepted. The complete wiring shall be of stranded copper and furnished with slip- over ferrules at both ends. Wiring shall also have crimped termination. The minimum cross-section cross-section of the wiring other than for step-position 2 transmission of OLTC shall be 2.5mm and that for oil pumps shall not be less than 6mm2 . Terminations of two conductors at one terminal point shall be made by suitable bridges and links of the terminals. CT wiring shall be of 4mm2 in metal conduit. All wiring should be oil resistant. All wiring of motors, Alarm and trip devices shall include an insulated separate protection earth conductor of at least the same cross-section as the line conductor. Suitable grounding conductors shall be provided for all grounding connections of the control cabinets and the terminal boxes with the transformer tank as well as for protection of earth connections between control cabinets and related doors or covers of terminal boxes. The cross-section shall not be less than 16mm2. Insulated grounding conductors shall be “green yellow” coloured. Electrical connections between accessories accessories and the control cabinet shall be enclosed throughout the total length. Made in metal raceways of corrosion-proof material material or conduit wiring of ample size and be safely fastened to the transformer tank to prevent mechanical damage or vibrations (to be subjected to approval). Only steel armouring of cables is not considered to be sufficient protection and therefore, is not acceptable. All cabling wiring of fan motors, pumps, measuring and monitoring devices etc. shall be designed for a conductor temperature of not less than 120C. Control cabinets and/or marshalling boxes, if any, shall be equipped with thermostatically and hydrostatically controlled heating elements to prevent condensation and moisture. A gland plate with a suitable fitting for the entrance of multi-core cables shall be installed at the bottom. bottom. They have to be sealed or plugged during transport. Cleaning, surface preparation and painting shall be in accordance with relevant articles of these Specifications. To prevent impermissible temperature rise within the cabinet, arising from sunshine, the fan control cabinet shall be protected by additional sheet aluminium or non-painted stainless sheet rigidly fixed at a certain distance around the cabinet and onto the door. Control cabinets shall be lighted by door-controlled lamps adequately sealed. Hinged doors shall be equipped with locking facilities. A rigid pocket for storing the concerned circuit diagram shall be installed on the inner side of the door, besides a metal plate showing all circuit connections terminal blocks. In any
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control cabinet where AC supply voltage is available, a fused spare plug standard universal socket for local use shall also be provided. Terminals shall be of single insertion type of ceramic suitable ford conductors up to a cross-section of not less than 10mm2 . 15. NAME PLATES AND OTHER DESIGNATION PLATES
Plates made of corrosion-proof material material rigidly supported shall be supplied as specified hereinafter. Plates shall be of polished stainless steel of top quality only, such as V4A, INOX A4 or equivalent Cr-Ni-Mo-Ti alloyed stainless steel (background clear, engraving black, 2 mm thick, and depth of engraving 0.5 mm). All plates other than those located on tank cover shall be easily and clearly legible from ground level. a)
A rating plate in accordance with IEC 60076. This plate shall also indicate the LI and AC withstand levels for all windings and, in addition, the switching impulse level for wi ndings of Um = 245 kV and above. Furthermore, the masses stated on this plate shall include total mass, untanking mass, transportation mass and insulation liquid mass.
b)
A connection diagram showing in detail the internal connections and the voltage vector relationship of the several windings and, in addition, a plan view of the transformer giving the correct physical relationship of the terminals.
c)
A loading plan plate showing transport dimensions and masses. This plate shall also warn the erection staff, not to remove any cover before filling the tank with oil to such a level where the windings are not exposed to the atmosphere.
d)
A plate showing the location and function of all valves and air release cocks, plugs and all monitoring equipment in the plan view and in the different elevations of the transformer. transformer. This plate shall also warn the operator to refer to maintenance instructions before applying vacuum treatment and not to operate vacuum application and vacuum equalising valves after oil filling under vacuum.
e)
Identification plates, alpha-numerical alpha-numerical numbered in accordance accordance with the relevant standards, for all fans, marshalling cabinets, breathers, valves including butterfly valves, cocks, accessories etc. (minimum size: 110 mm x 50 mm). In addition the function (description) of the related devices shall be clearly indicated on these plates. The alpha-numerical numbers on the identification plates shall be of such a size as to be clearly legible from the floor level.
f)
A diagram plate indicating the exact oil quantity required in the conservators above minimum minimum level dependent on the oil temperature.
g)
Plates showing in an approved manner all control, measuring and monitoring circuits and terminal blocks. These plates shall be rigidly fixed at the inner side of the front door of the concerned marshalling kiosk.
h)
Plates showing in an approved manner the control circuits and terminal blocks of the OLTC motor drive including filter units, if any. These plates shall be rigidly fixed at the inner side of the front door of the motor drive cubicle.
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16. DRAWINGS AND DOCUMENTS
The following drawings and documents shall be submitted individually for approval
General outline arrangement drawing with dimension and details of accessories/components/panels.
Rating and connection diagram plate
Schematic diagram of fan controls
Schematic diagram of tap changer controls
Drawings of cable boxes and termination arrangement
Drawings of foundation details
Indoor Auxiliary control panel drawing
Specification of the insulation Oil
Plate for arrangement of Valves and accessories
Outline of radiator
Outline of fan unit
Outline of oil-pump
Motor drive (circuit diagram plus parts list etc.)
Construction of globe valves and gate valves.
In addition, 5 (five) complete sets of detailed drawings of transformer, OLTC and operation and maintenance manuals including spare part lists (if any) shall be submitted prior to the delivery of the equipment. 17. TESTING AND INSPECTION
Each of the transformers shall be subjected to inspections and witness tests to be performed at the manufacturer's premises and test shop (recognised and certified at least by ISO 9001) and at site, as specified hereinafter to verify their conformity with the guaranteed and other design data. The Tenderers/Contractors is obliged to submit a detailed test program including detailed test connections for all dielectric tests - for approval in due time, prior to the tests. Detailed test schedules separately for each unit showing working-day-wise working-day-wise when each of the witness tests will be carried out shall be submitted for approval along with the test program as above. Successful witness type and routine tests shall be performed on one unit of each type before application of routine tests on any other unit of the same type. During all applicable witness tests the applied test frequency has to be supervised and to be stated in the test reports. The transformers shall be completely assembled in every respect. All of the tests shall be performed with all original bushings installed. The tests shall be performed in accordance with the latest issues of the Recommendations of the International Electrotechnical Commission (IEC-standards) supplemented by these Specifications. The following tests shall be performed in the presence of K-ELECTRIC:
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PID/TS/PTR/1.0 17.1
Factory Tests
17.1.1
Routine Tests
Measurement Measurement of voltage ratio at all tap positions
Check of vector group by voltmeter method
Measurement of winding resistances of all phases (phase to neutral, where applicable) and at all tap positions
Measurement of no-load losses and current from 90% to 120% of rated voltage in 5% intervals at rated frequency
Measurement of load losses and impedance voltages / short-circuit impedances at rated frequency at principal tap position(s) and all extreme positions
Switching impulse test for HV windings of Um= 245 kV and above. The test voltage shall be higher than 80% of the specified LI withstand test level in any case, and shall be selected from the relevant tables of IEC 60076-3
Lightning impulse test (full and chopped wave) for all power windings of transformers having windings of Um= 100 kV and above. The following test sequence shall be applied: -
One reduced level full impulse (lines and neutral)
-
One reduced level chopped impulse (1st. phase only)
-
One full level full impulse (lines and neutral)
-
One reduced level chopped impulse (lines only)
-
Two full level chopped impulses (lines only)
-
Two full level full impulses (lines and neutral).
The peak value of chopped impulse shall be at least 1.1 times the amplitude of full impulse. Neutral points of the windings under test shall not be grounded through resistors other than a measuring shunt. Impulse tests on neutrals shall be applied directly with all line terminals earthed, either solidly or through adequate resistors. The test voltages shall be measured via appropriate voltage dividers and shall be clearly indicated by peak-voltmeters and/or in oscillographic or digital records.
Separate-source Separate-source AC withstand voltage test in accordance accordance with IEC 60076-3, clause 11.
Induced AC withstand voltage tests with measurement of partial discharge: -
Short-duration induced AC withstand voltage test (ACSD) in accordance with IEC 60076-3, clause 12 for transformers with high-voltage windings up to Um= 170 kV
-
Monitoring of partial discharges for all windings of Um= 100 kV and above during short-duration induced AC withstand voltage test (ACSD) as per IEC 60076-3, clause 12. This test is mandatory independent of the country of the manufacturer
-
Long-duration induced AC withstand voltage test (ACLD) in accordance with IEC 60076-3, clause 12 (symmetrical three-phase test) with measurement of partial discharges for all transformers
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with high-voltage windings of Um= 245 kV and above at all transformer windings of Um= 100 kV and above.
Measurement of the capacitance and insulation power factor at min. 10 kV
Measurement of insulation resistance (R15, R60, R180) at 5000 V DC
Measurement of the insulation resistance (R60) between the core and tank at 2500 V DC
Measurement of ratio and polarity check on current transformers
Determination of efficiencies at 125%, 100%, 75%, 50% and 25% load at power factor 1.0 and 0.8 (documentation only)
Measurement of the cooling losses at rated supply voltage and frequency, and check of rotation direction of fans
Calibration and current injection test (45 minutes) on winding temperature based on results of heat run tests
Operation tests on OLTC
Measurement of zero-sequence impedance (at rated frequency) at principal tap(s) and all extremes, where applicable (no-load zero-sequence impedances at primary and secondary sides and short circuit zero-sequence impedance at primary and secondary side)
Applied over-voltage test at 2000 V, AC, 60 sec. on wiring, control and supervisory equipment (on 60076-3. motors 1000 V AC plus 2 x Un, and 500 V AC on PT 100).Dielectric routine tests as per IEC 60076-3.
Tests on on-load tap-changers, and drive mechanism in accordance with IEC 60214.
Functional test on parallel operation of transformers.
Measurement of dielectric strength of transformer oil.
17.2
Type Tests and Special Tests
All type test as per relevant IEC shall be performedon the same transformer as offerd. Induced AC withstand voltage tests t ests -
Short-duration induced AC withstand voltage test (ACSD) in accordance with IEC 60076-3, clause 12 for transform tr ansformers ers with high-voltage windings above Um= 170 kV
-
Monitoring of partial discharges for all windings of Um= 100 kV and above during shortduration induced AC withstand voltage test (ACSD) as per IEC 60076-3, clause 12. This test is mandatory independent of the country of the manufacturer.
Lightning impulse test (full and chopped wave) for all power windings of transformers not having windings of Um= 100 kV and above. The following test sequence shall be applied: -
One reduced level full impulse (lines and neutral)
-
One reduced level chopped impulse (1st. phase only)
-
One full level full impulse (lines and neutral)
-
One reduced level chopped impulse (lines only)
-
Two full level chopped impulses (lines only)
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Two full level full impulses (lines and neutral).
The peak value of chopped impulse shall be at least 1.1 times the amplitude of full impulse. Neutral points of the windings under test shall not be grounded through resistors other than a measuring shunt. Impulse tests on neutrals shall be applied directly with all line terminals earthed, either solidly or through adequate resistors. The test voltages shall be measured via appropriate voltage dividers and shall be clearly indicated by peak-voltmeters and/or in oscillographic or digital records.
Measurement Measurement of the acoustic sound level at rated voltage and frequency
Measurement Measurement of the harmonic content of no-load current at 90%, 100% and 110% of rated voltage at rated frequency
Dissolved gas-in-oil analysis by chromatography prior to dielectric tests, after completion of dielectric tests and after each of the heat-run tests
Steady state temperature rise tests at every cooling method and at all specified loading conditions at the highest current taps of the windings under test and with the highest applicable total losses to be applied. During all of the heat-run tests the top and bottom oil shall be measured directly in the oil-flow in radiators headers by approved temperature sensors at a minimum of four of their inlets and outlets each connected directly to the transformer tank (in case of common common headers on each inlet and outlet of the common headers). In case of measurements of top oil temperatures taken in pockets the final top oil temperature shall be corrected by +2 K. Measurements on radiator and/or tank walls etc. are not acceptable. acceptable.
Short-circuit Test in accordance with latest IEC Standard 60076-5 to ascertain both thermal and dynamic withstand conditions. Clauses 3.2.3 & 4.2.6 mentioned in IEC 60076-5 (2006) shall be followed to determine the withstand ability of tertiary (stabilizing winding) of YNy0d11 Vector Group transformer.
Switching impulse test (SI) for the line terminal,
Separate source AC withstand voltage test (applied potential test)
Long-duration induced AC voltage test (ACLD),
Dielectric type tset and special tests as per IEC 60076-3.
Determination of capacitances windings-to-earth, windings-to-earth, and between windings,
Determination of transient voltage transfer characteristics.
Measurement Measurement of zero-sequence impedance(s) on three-phase transformers (10.7).
Measurement Measurement of the power taken by the fan and oil pump motors.
Measurement Measurement of insulation resistance to earth of the windings, and/or measurement of dissipation factor (tan 6) of the insulation system capacitances. (These are reference values for comparison with later measurement in the field. No limitations for the values are given here.) If test methods are not prescribed in this standard, or if tests other than those listed above are specified in the contract, such test methods are subject to agreement
Tests on on-load tap-changers, and drive mechanism in accordance with IEC 60214
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Tests on Transformer Tank and Accessories
Prior to the acceptance tests, the Tenderer/Contractor shall submit the following test certificates as a minimum requirement:
Vacuum test on tank and all other oil-filled compartments (to be applied at 1.5 mbar for at least 5 hours).
Pressure test on tank and all oil-filled compartments at min. 1.0 bar measured on tank bottom for at least 24 hours.
Ultra-sonic tests on tank cover and self-supporting tank bottom.
Insulating oil used during factory tests and at site.
Bushings: all routine and type test on bushings in accordance with 60137.
Current transform t ransformers. ers.
Buchholz relays.
Tap changers and related equipment
Core losses of laminations (W15/50 and W17/50).
Pressure Relief Device Test
17.4
Site Tests (minimum requirements)
The following tests shall be performed at site as a minimum requirement:
Measurement of the excitation current with low voltage (AC, 3-phase) when the transformer is completely de-magnetised
Oil tightness test on tank at 0.3 bar over oil level, 24 hours
Measurement Measurement of voltage ratio at all tap positions
Check of vector group by voltmeter method
Measurement Measurement of winding resistances at all tap positions
Measurement Measurement of the winding insulation resistances (R15, R60, R180, R600) at 5000 V, DC
Measurement Measurement of the insulation resistance (R60) between the core and tank at 2000 V, DC
Measurement Measurement of the insulation resistances on auxiliary wiring at 1000V, DC
Measurement Measurement of the dielectric strength of the insulation oil
Measurement of tan value of oil
Dissolved gas-in-oil analysis
Check of water content in ppm. for oil
Re-calibration Re-calibration and current injection test on winding temperature indicators (45 min.)
Functional test on cooling plant, including check of rotation direction of motors
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Functional tests on control and supervisory equipment
Functional tests on OLTC equipment
Visual checks.
18. CORROSION PROTECTION 18.1
Responsibility and Guarantees
The Employer/Engineer shall have access at all times for inspection of the work and all pertinent materials during preparation and progress of the work. Should any work or material be found to be defective or not in compliance with the Engineer's requirements, correction or replacement by the Contractor at his own cost is essential. Inspection of coating by the Employer/Engineer will neither relieve the paint manufacturer from his responsibility for the good quality of his products nor the Contractor from his responsibility for acquiring the specified quality of materials or the correct performance of the work. All material shall be protected against corrosion and damage through the influence of the prevailing tropical conditions including the incidence of dust, sandstorms and seawater spray. The Contractor shall bear the responsibility for all losses and damages which may occur through inadequate measures against such influences and shall repair the damaged parts at his cost. The Contractor shall bear the full responsibility for galvanizing and paint applied by him or by others. Corrosion protection shall be guaranteed for five years after the Employer's/Engineer's inspection and final acceptance. The Contractor shall provide a Guarantee Performance Bond to assure the performance of extended guarantee obligations for corrosion protection. The Contractor shall carry out during the extended guarantee period any repair on the corrosion protection applied by him free of cost after being intimated by the Employer. If the necessary repairs are not carried out to the satisfaction of the Employer, the repairs shall be carried out by others and the costs thereof shall be borne by activating the Performance Bond for these extended guarantee obligations. 18.2
Test Instruments
The dry film thickness on steel shall be measured by means of an electromagnetic dry film thickness gauge such as the "Minitector" and a magnetic one such as the "Microtest". During application of paint the wet film thickness shall be checked continuously by means of an approved wet film thickness gauge. Also, the dew point has to be controlled continuously by means of approved instruments and methods. An approved type of multi-cross cutter for adhesion tests is also required. For the above mentioned tests which shall be performed in the presence of the Engineer all respective instruments shall be provided by the Contractor.
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Materials
All materials of successive coats shall be supplied by the same manufacturer and the Engineer's approval shall thus be obtained before relevant orders are placed. Materials shall be used from a manufacturer who has good experience with his products with regard to corrosion protection in such special areas. Materials which are to be supplied and used for the surface protection work (e.g. paints, filling cements, metallic coating materials) must comply with quality regulations and standards, the following provisions and any special permit conditions and official regulations. If a certain material is stipulated in the Specification, it shall be possible, with the agreement of the Engineer, to use a material which can be shown to be at least equal in quality and suitability. Paint which looks liverish, has gelled or otherwise deteriorated deteriorated during storage storage shall not be used. The quality of the paints should be such that they do not form a solid sediment but, at most, a slight skin in unopened original containers over a period of six months calculated from the manufacturer's delivery date. A paint which has formed a solid sediment or more than just a slight skin in the unopened original containers by the time of use or which cannot be processed satisfactorily may not be used. A sediment shall be regarded as solid if it cannot be dispelled again quickly and completely by stirring with an adequate electric driven mixer (maximum speed 350 to 400 rpm). Paints which do not have to be prepared by mixing several constituents just prior to use should be brought to the building site in such a state of readiness that they need only be adjusted to brushing or spraying consistency to meet the relevant working conditions (e.g. temperature) by adding the particular thinners in accordance with the manufacturer's instructions. In the case of paints which are only prepared for use immediately before application by mixing several constituents (e.g. multiconstituent types), the various constituents should be of such a kind that mixing at the building site is restricted to the necessary extent. extent. If the Contractor selects, for the protection of steel or aluminium alloys against corrosion, paints and filling cements for which no regulations, permit conditions or technical conditions of delivery exist, they may be used if the Contractor can prove their suitability for the necessary degree of protection against corrosion, and after approval of the Engineer
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18.4
Galvanized Steel Surfaces
18.4.1
General Requirements
This Article defines the minimum requirements for galvanizing as well as for surface cleaning and preparation for the protective coating of galvanized steel surfaces. All steel for outdoor use is to be galvanized and further painted if specified. The galvanizing procedure shall be started only after having finished all chipping, trimming, fitting and bending. Also, all drilling, punching, cutting and welding shall have been completed and all burns removed. All steel, including bolts, nuts and washers, shall be galvanized at the manufacturer's premises by means of hot-dipping in accordance with internationally recognized standards such as ASTM A 239 or equivalent, and the zinc coat applied shall have the following thicknesses: - Minimum 80 micron/approximately 600 g/m2; - Maximum 120 micron/approximately 900 g/m2. Where members are of such length that they cannot be dipped in one operation, great care shall be exercised to prevent warping. All holes in material shall be free of excess spelter after galvanizing. galvanizing. All material shall be safe-guarded against embrittlement during galvanizing. The zinc coating shall be uniform in thickness and so applied that it will adhere to the surface of the steel. Major damage to galvanizing shall be cause for rejection. Material on which galvanizing has been damaged shall be re-dipped unless the damage is minor and local and can be repaired by applying galvanizing repair paint, to the satisfaction satisfaction of the Engineer. If particularly specified for protection during transport and erection, all galvanized steel members shall be coated with a suitable pre-primer with minimum thickness of 40 micron and matching the primer to be applied after erection. If not otherwise specified, galvanized steel surfaces shall be chromated with approximately 3 micron thickness. Single items such a cable trays, fences, etc. may be galvanized and PVC covered if so approved by the Engineer.
18.4.2
Cleaning and Surface Preparation
Prior to painting the galvanized steel surfaces shall be carefully brushed with fresh water in order to remove all foreign matters such as salt, white rust and zinc corrosion products, dust, sand and dirt. After erection and prior to the painting at site, the surfaces shall be cleaned thoroughly by the use of mechanical steel brushes and fresh water to remove all foreign matter. After cleaning, all surfaces shall be checked for any damage caused to the galvanizing. Minor damage shall be carefully freed from dust and shall be touched up with a zinc-chromate primer as specified. Major damages and welding seams shall be sand-blasted in accordance with SA 3 (SIS 055900) and painted with a zinc rich primer, in specific cases re-galvanizing may be required.
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Painting at Manufacturer's Premises
All metal surfaces such as for switchgear, cubicles and panels, structures and supports, casings, enclosures, frames and subframes, etc. i.e. all equipment or parts thereof incorporated in the work, shall be chemically pre-treated: - Steel: zinc-phosphate zinc-phosp hate - Aluminium: chromating - Other materials: adequately adequately treated Followed by a coating system (preferably powder coating). The painting of the panel should conform to specification C3 for indoor and C4 for out door panels. Extra amounts of paint sufficient for all repairs shall be made available and shall be applied to all surfaces after erection and before commissioning of equipment, if so required. The final coat shall preferably comply with code RAL 7035 " Light grey", " or as directed or approved otherwise by the Engineer. In any case, at an early stage the Contractor shall explain in great detail all corrosion protection measures he intends to take, indicate the relevant standards for testing the applied measures, and apply for the Engineer's approval of the above mentioned steps. 18.5.1
Painting
Due to the unfavorable atmospheric atmospheric conditions particular attention should be given to the protection of all iron/ metal work. The methods proposed and the means adopted should be fully described in the Bid. All surfaces shall be thoroughly cleaned of rust, seale, grease and dirt and other foreign matter and all imperfections shall be removed by means of approved methods. The following treatments shall be applied: a) External surfaces
All steel surfaces shall be sand blasted in accordance with DIN 5598, Part 4(equivalent to SIS 055900) and shall then be painted in the following sequence:
two (2) primer coats Binder: Pigment:
2 x 35 µm epoxy resin hardened with polyamide
titanium dioxide. Zinc oxide. Zinc phosphate, tinting additives
one ( 1) intermediate intermed iate coat Binder: epoxy resin hardened with polyamide Pigment:
35µm
titanium dioxide, micaceous micaceous iron oxide, tinting additives
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two (2) top coats (polyurethane base) Binder:
polyurethane hardened with isocyanate.
Pigment:
titanium dioxide, micaceous micaceous iron oxide, tinting additives
Coating thickness
Total
150 µm
The colour code shall be RAL 7001. If hot-dip galvanized radiators etc. will be provided the same painting method shall be applied, however, instead of two primer coats one adhesive coat and one coat shall be applied. In this case, the mean thickness of galvanizing shall be 55 µm. Mechanical damage damage shall be repaired at site. b) Internal Surfaces.
Inside the transformer/reactor vessel, sand-blasting shall be performed in accordance with DIN 55928. Part 4. (equivalent to SIS 055900). After that, a solvent-free, oil-resistant coating coating shall be applied. The minimum dry film thickness shall be 40 µm.
19. CAPITALISATION OF LOSSES
When evaluating the individual tenders received from the various tenderers the transformer losses will be capitalised as follows: a)
No-load losses
US$
6,000.00 per kW
b)
Load losses
US$
3,000.00 per kW
The auxiliary power losses will be added to the load losses. 20. GUARANTEED VALUES AND PENALTIES
The guaranteed values tendered by the Tenderers/Contractors Tenderers/Contractors in the Specific Works Data Sheets will be strictly observed by both the Tenderers/Contractors Tenderers/Contractors and the Employer. For the guarantee data not mentioned hereinafter tolerances in accordance with IEC 60076 shall apply. 21. LOSSES
If the no-load losses of a power transformer exceed the guaranteed value, an amount of US$ 6,000 per kW for each full kW in excess of the guaranteed value will be deducted from the Contract Price.
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PID
If the load losses (plus auxiliary power losses) of a power transformer exceed the value guaranteed, an amount of US$ 3,000 per kW for each full kW in excess of the guaranteed value will be deducted from the Contract Price. It is thereby understood that values of 0.5 kW and above will be rounded up to the next full kW. 22. RATED POWER AND OUTPUT
If the test of temperature rise carried out on any transformer should reveal that the temperature rise of the transformer exceeds the values guaranteed, the rated power and output of the transformer at operation conditions as specified above will have to be down-rated to such a degree as to obtain the temperature rise guaranteed. For each kVA of the actual transformer transformer rating below the guaranteed rated power and output as specified previously, an amount of US$ 25.00 will be deducted from the Contract Price of this transformer and all those transformers of the same design unless the Tenderers/Contractors, at his own expense, gives evidence that those transformers fulfil the guaranteed values. 23. NOISE LEVEL
Should the noise level measured at the specified distance exceed the required values for power transformers, K-ELECTRIC will penalise the excess at a rate of US$ 5,000.00 per dB (A). Hereby is understood that values of 0.5 dB (A) and above will be rounded up to the next full dB (A). 24. REJECTION
K-ELECTRIC shall have the right to reject any transformer if the actual values are in excess of the guaranteed values by more than the margins specified hereunder (including the tolerances):
No-load losses
+ 15%
Load losses (forced cooling)
+ 10%
Total losses
+ 10%
Noise level
+ 3 dB(A)
Temperature rise limit
+ 2.0 K
Impedance
±5%
For all of the other values the margins stated in IEC standards are applicable, unless specified otherwise elsewhere in these Specifications. Specifications. 25. TRANSPORT
The core and coils shall be completely dried before shipment and shall be assembled assembled with the transformer transformer tank. In order to facilitate safe handling and shipping of power transformers, as many external accessories as possible, including the bushings, shall be removed and replaced with special shipping covers. Transport of completely assembled power transformers is not acceptable. Butterfly valves and/or other isolating valves mounted directly on the tank shall not be removed for transport in order to avoid ingress of humidity during installation at site. All of those parts dismantled for
TECHNICAL SPECIFICATION POWER TRANSFORMER Specification No.
Version
Date of Issuance
Page
Issuing Section / Department
1.0
Feb 19, 2015
Page 38 of 49
PID
PID/TS/PTR/1.0
shipment shall be fitted again only after filling the tank with oil to such a level where windings will not be exposed to the atmosphere. Bushings, radiators and other accessories which may be affected by moisture shall be moisture-proof packed in seaworthy packing. Packing material, including oil drums, shall not be returned. As far as is practicable the power transformers shall be supplied and shipped with their initial oil filling in the main tank. If the transportatio tr ansportation n of the power transformers transformers with oil filling is not practicable, they shall be despatched with automatic dry nitrogen or dried air filling arrangement. During transport, each transformer shall be equipped with devices maintaining a constant pressure in the equipment concerned and facilitating tapping-up by suitable automatic facilities from reserve bottles. In this case, drained oil of at least the same quality as used during factory tests shall be delivered in drums or containers in a sufficient quantity to refill the transformers and to replenish losses during subsequent processing at site. 26. IMPACT RECORDERS
Electronic transport monitors (impact recorders with electronic data storage), capable of indicating all horizontal and vertical impacts, shall be rigidly attached to each power transformer. Provisions must be made to ensure that these indicators are sealed, that they will be completely functional functional without interruption of indicated records during the entire period of shipment, including loading and unloading, and to ensure that K-ELECTRIC will receive clearly indicated data by breaking the seal. Instructions for interpretation of the recorded data and a user manual for th e equipment shall be provided prior to shipment.
SPECIFIC WORKS DATASHEET
K-Electric
Version 1.0
Specification No. PID/TS/PTR/1.0
Page 39 SPECIFIC WORKS DATA TRANSFORMERS Power Transformers, 31.5/40 MVA, 132 ± 15%/12 kV
Sr. No.
REQUIRED
1.00
GENERAL
1.01
Manufacturer name
1.01.1
type designation
1.01.2
country of manufacturer
1.02.1
Manufacturer's authorization letter attached
1.02.2
Customer's certificates on satisfactory
yes
yes
experience attached 1.03 1.04 1.05
Single or Three-Phase unit
1.06
Magnetic core
1.06.1
type of core
1.06.2
type of stacking
1.06.3
three or five-limb core
1.07
Type of tank
1.08
Tank fully vacuum proof
1.09
Number of windings
1.10
Insulation oil
1.10.1
manufacturer
1.10.2
type
1.10.3
specification of oil (general)
1.11
outdoor
Kind of installation Applicable standards
TENDERED
IEC
60076, 60354 three-phase
core type step-lap three upper flange type yes No.
two plus stabilising
IEC
60296, class II yes
For parallel operation with existing transformer parameters to be suitably coordinated
2.00
RATINGS
2.01
Rated power
2.01.1
at ONAN cooling
MVA
31.5 / 31.5 / 10.5
2.01.2
at ONAF cooling
MVA
40 / 40 / 13.3
2.02
Rated frequency
Hz
50
2.03
Maximum ambient temperature
0
C
50
2.04
Maximum service altitude
m
1000
2.05
Temperature rise limits at all tap changer settings
2.05.1
oil / top
K
45
2.05.2
windings / average
K
50
2.05.3
windings / hot spot
K
63
2.05.4
hot spot factor (H) H
1.3
2.05.4.1 2.06
core of core-form type Rated voltages (no-load) for tranformation ratio
2.06.1
primary
kV
132
2.06.2
secondary (in case of parallel operation with
kV
12
kV
12
already existing transformers to be suitably coordinated) 2.06.3
tertiary
___________________________________________ _____________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________ TENDERER`s ______ STAMP & SIGNATURE
.
K-Electric
Version 1.0
Specification No. PID/TS/PTR/1.0
Page 40 SPECIFIC WORKS DATA TRANSFORMERS Power Transformers, 31.5/40 MVA, 132 ± 15%/12 kV
Sr. No.
REQUIRED
TENDERED
2.07
Rated Voltages for insulation class: E124
2.07.1
Primary
kV
145
2.07.2
Secondary
kV
24
2.07.3
Tertiary
kV
24
2.08
Rated current
2.08.1
primary
2.08.1.1
at tap -1-
A
2.08.1.2
at tap -13 -
A
2.08.1.3
at tap -25-
A
2.08.2
secondary
A
2.08.3
tertiary
A
2.09
Voltage variation range
± kV
20
2.10
Tapping range
±%
15
2.11
Number of steps
± steps
2.12
Principle tapping
kV
2.13
Tapped winding
HV
2.14
Continuous power at all taps
yes
2.15
Permissible load of neutral point
2.16
Vector group symbol
2.17
Magnetic flux density at rated voltage & frequency
TESLA
2.18
No-load losses
kW
2.19
No-load current (Io/In)
%
2.20
Core losses (W17/50)
W /kg
2.21
Impedance voltage-primary/secondary (31.5/40MVA basis)
%
12 x 1.25 132
100 YNyn0(d11) max. 1.6
max. 1.05
2.21.1
tap changer position -1-
%
2.21.2
tap changer position -13-
%
16/20.4
2.21.3
tap changer position -25-
%
18
2.22
Load losses (40MVA basis)
2.22.1
tap changer position -1-
kW
2.22.2
tap changer position -13-
kW
2.22.3
tap changer position -25-
kW
2.23
Power consumption of cooling plant
2.24
Winding insulation design:
kW
2.24.1
primary winding
uniform
2.24.2
secondary winding
uniform
2.24.3
tertiary winding (stabilising)
uniform
2.25
Insulation Level / Primary winding
2.25.1
power frequency withstand voltage (line/neutral)
kV
275/275
2.25.2
lightning impulse level (line/neutral)
kV
650/650
kV
50/50
2.26 2.26.1
Insulation Level / Secondary winding power frequency withstand voltage (line/neutral)
___________________________________________ _____________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________ TENDERER`s ______ STAMP & SIGNATURE
.
K-Electric
Version 1.0
Specification No. PID/TS/PTR/1.0
Page 41 SPECIFIC WORKS DATA TRANSFORMERS Power Transformers, 31.5/40 MVA, 132 ± 15%/12 kV
Sr. No. 2.26.2 2.27 2.27.1 2.27.2 2.27.3
REQUIRED lightning impulse level (line/neutral)
TENDERED
kV
125/125
kV
50
kV
125
Insulation Level / Tertiary winding power frequency withstand voltage Lightining impulse level
yes
insulation levels to be coordinated with actual transferred over-voltages s
2.28
Rated duration of short circuit
2.29
Symmetrical short circuit withstand current
2.29.1
HV winding
kA
2.29.2
LV winding
kA
2.29.3
tertiary winding
kA
3.00
TESTS
3.01
Lightning impulse test
3.02
Full wave
3
on each unit
3.02.1
primary (neutral/lines)
kV
650/650
3.02.2
secondary (lines/neutral)
kV
125/125
3.03
on each unit
Chopped wave (lines only)
3.03.1
primary
kV
715
3.03.2
secondary
kV
140
3.04
on each unit
Separate source AC voltage withstand test
3.04.1
primary
kV
275
3.04.2
secondary
kV
50
3.04.3
tertiary
kV
50
3.05
on each unit
Induced AC voltage withstand test, acc. to IEC 60076-3, clause 12.2 and monitoring of partial discharges
3.05.1
test voltage / primary
kV
275
3.05.2
test voltage / secondary
kV
24
3.05.3
permissible partial discharges at U 2 = 1.3xUm/√3
pC
max. 300
3.05.4
test frequency
Hz
3.06
Test of temperature rise (at all kinds of cooling)
on one unit
3.07
Test of noise level (special test)
on one unit
3.08
3.09
All other type, routine, and special tests according to the specifications Short circuit test
3.09.1
name of independent testing laboratory who carried out the short circuit test on similar transformer
3.09.2
test certificate attached
3.09.3
validity of quality control certificates
3.09.4
name of issuing authority
4.00
yes
yes
OPERATION DE DETAILS
___________________________________________ _____________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________ TENDERER`s ______ STAMP & SIGNATURE
.
K-Electric
Version 1.0
Specification No. PID/TS/PTR/1.0
Page 42 SPECIFIC WORKS DATA TRANSFORMERS Power Transformers, 31.5/40 MVA, 132 ± 15%/12 kV
Sr. No.
REQUIRED
4.01
Cooling method
4.02.1
Number of groups
4.02.2
Number of fans
TENDERED
ONAN/ONAF
4.02.2.1
Number of fans in each group
4.02.2.2
Number of spare fans
4.02.2.3
Number of standby fans for emergency loading in case of outage of all forced cooling
4.02.3
Single phase or Three phase Fans
4.03
Mode of connection of fans
4.04
Sequential starting of two fan groups
4.05
4.07
Permissible over-load and duration (in minutes)
max. 65
as per IEC
0
min.
0
min.
0
min.
at 30 C
4.07.1.2
at 40 C
4.07.1.3
at 50 C 30 % over-load 0
min.
0
min.
0
min.
4.07.2.1
at 30 C
4.07.2.2
at 40 C
4.07.2.3
at 50 C 40 % over-load 0
min.
0
min.
0
min.
4.07.3.1
at 30 C
4.07.3.2
at 40 C
4.07.3.3
at 50 C
4.07.4
dB(A)
20 % over-load
4.07.1.1
4.07.3
yes vertical
Noise level at a measuring distance of 2.0 m (all forced cooling in operation)
4.07.2
by groups
Air-blow direction of fans
4.06
4.07.1
Single
50 % over-load 0
min.
0
min.
0
min.
4.07.4.1
at 30 C
4.07.4.2
at 40 C
4.07.4.3
at 50 C
5.00
DESI ESIGN DETA ETAILS AN AND FEAT EATURE URES
5.01
Current densities at rated power
5.01.1
primary
A/mm
2
max. 2.62
5.01.2
regulation windings
A/mm
2
max. 2.62
5.01.3
secondary
A/mm
2
max. 2.62
5.01.4
tertiary
A/mm
2
max. 2.62
5.02
0
Winding resistances at 75 C
5.02.1
primary
Ω / Phase
5.02.2
regulation windings
Ω / Phase
5.02.3
secondary
Ω / Phase
___________________________________________ _____________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________ TENDERER`s ______ STAMP & SIGNATURE
.
K-Electric
Version 1.0
Specification No. PID/TS/PTR/1.0
Page 43 SPECIFIC WORKS DATA TRANSFORMERS Power Transformers, 31.5/40 MVA, 132 ± 15%/12 kV
Sr. No. 5.02.4 5.03
REQUIRED Ω / Phase
tertiary Type of windings
5.03.1
primary
5.03.2
regulation windings
5.03.3
secondary
5.03.4
stabilising windings
5.04
Winding conductor material (all windings)
5.05
Winding connections
5.06
Branded or core bolt construction
5.07
Thermal class of insulation
5.08
Insulation material
5.08.1
primary
5.08.2
secondary
5.08.3
tertiary
5.08.4
tapping leads
5.08.5
core lamination
5.09
TENDERED
copper braced or crimped
A
Radiators
5.09.1
wall thickness
mm
min 1.2
5.09.2
width
mm
470 - 520
5.10
Type of valves butterfly valves
5.10.1
radiator valves
5.10.2
valves for silicagel breathers
5.10.3
on tank and conservator
globe or gate valves
5.10.4
oil sampling valves
globe or gate valves
5.11
three-way valves
Cooling fans
5.11.1
total weight, incl. motor
kg
5.11.2
overall diameter
mm
5.12
Efficiencies
5.12.1
at 25 % of rated power power
%
5.12.2
at 50 % of rated power power
%
5.12.3
at 75 % of rated power power
%
5.12.4
at 100 % of rated power
%
5.12.5
at 125 % of rated power
%
5.12.6
at 150 % of rated power
%
5.13
0
Voltage regulation at 75 C and rated power
5.13.1
at power factor 0.80
%
5.13.2
at power factor 0.85
%
5.13.3
at power factor 0.90
%
5.13.4
at power factor 0.95
%
5.14
Thickness of tank cover, walls and bottom
5.14.1
cover
mm
5.14.2
walls
mm
min. 25
___________________________________________ _____________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________ TENDERER`s ______ STAMP & SIGNATURE
.
K-Electric
Version 1.0
Specification No. PID/TS/PTR/1.0
Page 44 SPECIFIC WORKS DATA TRANSFORMERS Power Transformers, 31.5/40 MVA, 132 ± 15%/12 kV
Sr. No.
REQUIRED
TENDERED
5.14.3
length of transformer less than 2500 mm
mm
min. 6
5.14.4
length of transformer more than 2500 mm
mm
min. 9
5.14.5
bottom
mm
5.14.6
self-supporting tank bottom
mm
min. 30
5.14.7
cross-beam supported tank bottom
mm
min. 12
5.14.8
nominal internal pressure at full load
max. bar
5.14.9
internal withstand test pressure at full load
bar
6.00
BUSHINGS
6.01
Primary (Lines an and Ne Neutral)
6.01.1
Manufacturer
6.01.2
country of manufacturer
6.01.3
Type
6.01.4
Applicable Standard
Trench (France) or Passoni Villa (Italy) oil/Air IEC
60137
6.01.5
Rated current
A(min)
6.01.6
Power frequency test voltage
kV
275
6.01.7
Lightning impulse level
kV
650
6.01.8
Minimum creepage distance
mm
6.01.9
Bushing insulator
6.01.9.1
manufacturer
6.01.9.2
country of manufacturing
6.01.9.3
material
6.01.9.4
type
6.01.9.5
length
mm
6.01.9.6
weight
kg
6.01.9.7
electrostatic capability
6.02
Secondar y (L (Li ne nes and Neutral )
6.02.1
Manufacturer
6.02.2
country of manufacturer
6.02.3
Type
6.02.4
Applicable Standard
1250
6525
Trench (France) or Passoni Villa (Italy) oil/air IEC
60137
6.02.5
Rated current
A
6.02.6
Power frequency test voltage
kV
50
6.02.7
Lightning impulse level
kV
125
6.02.8
Minimum creepage distance
mm
600
6.02.9
Bushing insulator
6.02.9.1
manufacturer
6.02.9.2
country of manufacturing
6.02.9.3
material
6.02.9.4
type
6.02.9.5
length
2500
mm
___________________________________________ _____________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________ TENDERER`s ______ STAMP & SIGNATURE
.
K-Electric
Version 1.0
Specification No. PID/TS/PTR/1.0
Page 45 SPECIFIC WORKS DATA TRANSFORMERS Power Transformers, 31.5/40 MVA, 132 ± 15%/12 kV
Sr. No.
REQUIRED
6.02.9.6
weight
6.02.9.7
electrostatic capability
6.02.10
Provision of testing cables
6.03
Tertiary (S (Stabilising)
6.03.1
Manufacturer
6.03.2
country of manufacturer
6.03.3
Type
6.03.4
Applicable Standard
TENDERED
kg
yes
oil/air IEC
60137
6.03.5
Rated current
A
6.03.6
Power frequency test voltage
kV
50
6.03.7
Lightning impulse level
kV
125
6.03.8
Minimum creepage distance
mm
600
6.03.9
Bushing insulator
6.03.9.1
manufacturer
6.03.9.2
country of manufacturing
6.03.9.3
material
6.03.9.4
type
6.03.9.5
length
mm
6.03.9.6
weight
kg
6.03.9.7
electrostatic capability
7.00
1000
CURRENT TRANSFORMERS (to be filled-in for each type of C.T.) (C.T. data are subject to separate approval) (C.T. Parameter to be coordinated with the yes
switchgear CTs and Protection requirement) 7.01
For Pr Pr ot otecti on on Pu Pur po poses, HV HV Si Side
7.01.1
Rated output (at lowest lowest lap)
7.01.2
Ratio
VA
30
7.01.2.1
primary
A
200
7.01.2.2
secondary
A
1
7.01.3
Class steady state
7.01.4
Class transient
7.01.5
Technical data to be co-ordinated with switchgear C.T.
7.02
For Pr Pr ot otecti on on Pu Pur po poses, LV LV Si Side
7.02.1
Rated output (at lowest lowest tap)
7.02.2
Ratio
5P20 TPS yes
VA
30
7.02.2.1
primary
A
2500
7.02.2.2
secondary
A
5
7.02.3
Class steady state
7.02.4
Class transient
5P20 TPS
___________________________________________ _____________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________ TENDERER`s ______ STAMP & SIGNATURE
.
K-Electric
Version 1.0
Specification No. PID/TS/PTR/1.0
Page 46 SPECIFIC WORKS DATA TRANSFORMERS Power Transformers, 31.5/40 MVA, 132 ± 15%/12 kV
Sr. No.
REQUIRED
7.02.5
Technical data to be co-ordinated with switchgear C.T.
7.03
For Pr Pr ot otecti on on Pu Pur po poses, TE TER Si Side
7.03.1
Rated output (at lowest lowest tap)
7.03.2
Ratio
TENDERED yes
VA
30
7.03.2.1
primary
A
100
7.03.2.2
secondary
A
5
7.03.3
Class steady state
7.03.4
Class transient
7.03.5
Technical data to be co-ordinated with switchgear C.T.
7.04 7.04
For For Prot Protec ecti tion on Purp Purpos oses es,, Tert Tertia iary ry Neut Neutra rall
7.04.1
Rated output (at lowest lowest tap)
7.04.2
Ratio
5P20 TPS yes
N.A. VA
7.04.2.1
primary
A
7.04.2.2
secondary
A
7.04.3
Class steady state
7.04.4
Class transient
7.04.5
Technical data to be co-ordinated with switchgear C.T.
7.05
For Protection Purposes
7.05.1
Rated output (at lowest lowest tap)
7.05.2
Ratio
5P20 TPS yes
N.A. VA
7.05.2.1
primary
A
7.05.2.2
secondary
A
7.05.3
Class steady state
7.05.4
Class transient
7.05.5
Technical data to be co-ordinated with switchgear C.T.
8.00
ON-LOAD TA TAP-CHANGER
8.01
Manufacturer
8.02
country of manufacturer
8.02
Type
8.02a
Applicable Standards
30
5P20 TPS yes
MR Germany
IEC
60214 60542
8.03
Rated through current
A
8.04
Rated switching capacity
kVA
8.05
Lightning impulse level (1.2 / 50 µs)
kV
750
8.06
Power frequency withstand test voltage
kV
325
8.07
Short-time current kA
6
8.07.1
2 s value
350 1000
___________________________________________ _____________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________ TENDERER`s ______ STAMP & SIGNATURE
.
K-Electric
Version 1.0
Specification No. PID/TS/PTR/1.0
Page 47 SPECIFIC WORKS DATA TRANSFORMERS Power Transformers, 31.5/40 MVA, 132 ± 15%/12 kV
Sr. No. 8.07.2
REQUIRED peak value
8.08
Type of connection
8.09
Type of switching
8.10
Type of regulation winding
8.11
Contact life (operations)
8.12 8.13
Auxiliary supply voltage
kA
TENDERED 15
neutral point diverter switch, Dr. Jansen coarse and fine min. 200,000 V, AC
400/230
Number of tap position transmitters:
8.13.1
contact type transmitters
No.
min. two
8.13.2
additional contact type transmitter with diodematrix for digital remote position indication
No.
one
8.13.3
resistor type transmitters
No.
min. two
8.13.4
additional position transmitter of the resistor type with tap position transducer, output: 4-20 mA
No.
one
9.00
MASSES SSES,, ME MEASUR SURES AN AND DRA DRAW WINGS NGS
9.01
Transformer masses
9.01.1
total mass
kg
9.01.2
transportation mass
kg
9.01.3
untanking mass
kg
9.01.4
mass of core
kg
9.01.5
mass of windings
kg
9.01.6
mass of tank and fittings
kg
9.01.7
mass of insulation liquid
kg
9.01.8
Weight of Copper
kg
9.02
Overall dimensions including bushings:
9.02.1
height
mm
9.02.2
depth
mm
9.02.3
width
mm
9.03
Shipping dimensions
9.03.1
height
mm
9.03.2
depth
mm
9.03.3
width
mm
9.04
Descriptions
9.04.1
dimensional drawings
No.
9.04.2
connection diagram
No.
9.04.3
pamphlet
No.
9.05
Size of winding conductor
9.05.1
Primary
mm
2
9.05.2
Secondary
mm
2
9.06
Number of Parallel conductors
No.
___________________________________________ _____________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________ TENDERER`s ______ STAMP & SIGNATURE
.
K-Electric
Version 1.0
Specification No. PID/TS/PTR/1.0
Page 48 SPECIFIC WORKS DATA TRANSFORMERS Power Transformers, 31.5/40 MVA, 132 ± 15%/12 kV
Sr. No.
REQUIRED
TENDERED
NITROGEN INJECTION EXPLOSION PREVENTATION AND FIRE PROTECTION SYSTEM POWER TRASNFORMER
A a)
1
Nitrogen Injection Type Depressurisation Equipment Manufacturer's name
2
Type designation
3
Country of manufacture
4
Activation Detector
5
Size range, mm
6
Pressure range, bar
7 8 8.1
8.2 9 9.1
9.2 10
11 12
13 14
15
b) 1
2 3 4
5 6
c) 1
2 3 4
5 6
Body material Blow over pressure is detected: By pressure sensors (Yes/No). By buchholz relay (Yes/No). Type of pressure sensors. Spring type (Yes/No). Membrane type (Yes/No). Does the system operate with transformer tank internal pressure or bypressure sensors (Yes/No). Does the system operate with buchholz relay (Yes/No). Is the offered system a transformer explosion preventation type (Yes/no). Is the offered system fire extinguishing type (Yes/No) Does vessel internal presure sonsors activate a fast depressurisation device (Yes/No). Is explosion vent equipment with intergrated sensors (Yes/No). Temprature Detectors Manufacturer's name Type designation Country of manufacture Size, mm Temprature, range, deg.C. Body material Explosion Venting Equipment Manufacturer's name Type designation Country of manufacture Size, mm Rated flow Body material
___________________________________________ _____________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________ TENDERER`s ______ STAMP & SIGNATURE
.
K-Electric
Version 1.0
Specification No. PID/TS/PTR/1.0
Page 49 SPECIFIC WORKS DATA TRANSFORMERS Power Transformers, 31.5/40 MVA, 132 ± 15%/12 kV
Sr. No. d) 1
2 3 4
5 6 7
e)
1 2 3
4 5
6
f) 1
2 3 4
5 6 7
g) 1 2 3 4 5 6 7
REQUIRED Shutter Manufacturer's name Type designation Country of manufacture Size, mm Opening time, sec Closing time, sec Body material Nitrogen Bottle size Quantity of nitrogen, bar Pressure of nitrogen, kg Material of gaskets for values. Is Nitrogen injected in closed vessel in order to stop flammable gas generation (Yes/No) Is Nitrogen injected in closed vessel in order to stop expel the explosion flammable gases outside the transformer (Yes/No) Control Box Manufacturer's name Type designation Country of manufacture Size, mm Body material Mounting arrangemet Manual,electric and automatic operation Remote Control Panel Manufacturer's name Type designation Country of manufacture Dimentions, mm*mm*mm mass.Kg Mounting arrangement Manual, electric and automatic operation
B
FIRE EXTINGUISHERS
a)
Fire Extinguishers Manufacturer's name Model Type Size
1
2 3 4
b) 1 2
3 4
TENDERED
Mobile CO2 Fire Extingusher Cart Manufacturer's name Model Type Mass of CO2 in the steelbottle, kg.
___________________________________________ _____________________ ____________________________________________ ____________________________________________ ____________________________________________ ____________________________ TENDERER`s ______ STAMP & SIGNATURE
.
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