ep ms p4 s4 035 issue 2 2011 castresintx

Specification for 11/0.433 kV Dist. Transformers, Dry Type (Cast Resin) EP-MS-P4/S4-035

Issue : 2 16-10-2011 unclassified of 27

EP-MS-P4/S4-035

Specification for 11/0.433 kV Distribution Transformers, Dry Type

(Cast Resin), Ground Mounted for Indoor Applications



Document Control

Department Document Type Document Title

EP Material

Specification Standards

EP-MS-P4/S4-035 Specification for

11/0.433 kV Distribution Transformers, Dry Type (Cast Resin) Ground Mounted for

Indoor Applications

Issue Approval

Prepared By Approved By

Materials Standards & Specification Engineer

Manager, EN Planning Dept.

Signature: Signature:

Issue Record

Issue No. Date Reason for re-issuing Document

0.0 06.02.2005 First issue of Materials Specification Standards

1.0 05.02.2010 Review of Materials Specification Standards

2.0 16.10.2011 Review of Materials Specification Standards

3.0

4.0

5.0

Key Words : Specification for 11/0.433 kV Distribution Transformers, Dry Type (Cast Resin) Ground Mounted for Indoor Applications.

Review Frequency : Every 3 years When this document is approved for publishing on the intranet, a copy of its Document Control page should be sent to the QA section who is custodian of KM quality management system.



INDEX

SL NO DESCRIPTION PAGE

NUMBER

1. SCOPE 5 2. ENVIRONMENTAL CONDITIONS 5

3. SYSTEM CONDITIONS 5/6 4. APPLICABLE STANDARDS 6/7 5. GENERAL DESIGN FEATURES 7 6. RATINGS & CHARACTERISTICS 1 Service conditions & Temperature rise limits 8

2 Ratings 8/9 3 Short Circuit ratings. 9 4 Tapping Range & Method 9 5 Magnetic core Material & Flux density 9 6 Thermal Insulation class of windings 9 7 Noise Levels 10 8 Climatic, Environmental & Fire behavior class 10

7 RATINGS, CONNECTION PLATE DETAILS & MARKING OF

TERMINALS

1. Rating & Connection Plates. 10/11 2. Marking of Terminals 11

8. GENERAL CONSTRUCTION & FITTINGS 1. Magnetic core & bus bars 11 2. Windings 12 3. Enclosure. 13 4. Fittings and accessories 13/14/15 5. Corrosion protection & painting 15 6. Cable Boxes 16

9. QUALITY CONTROL 16 10. TESTS 16/17 11. TASTING, INSPECTION & DELIVERY 17/18 12. INFORMATION & DOCUMENTS TO BE SUBMITTED BY

BIDDERS 18/19

13. WARRANTY 20 14 DEVIATIONS FROM THE TECHNICAL SPECIFICATION 20 15 RESTRICTIONS ON OUT-SOURCING 20



APPENDICES 14 Appendix A- Transformer 11kV Cable Box for All Sizes 21 15 Appendix B -Transformer LV Cable Box for 500/1000kVA Sizes 22 16 Appendix C-Transformer LV Cable Box for 1600kVA Sizes. 23

TABLES 17 TABLE-B1/ Details of Cable boxes 24 18 TABLE-B2/ Minimum Clearances in Cable boxes. 24 19 TABLE-B3/ No & Size of Cables in LV Cable Box 24

ILLUSTRATIONS 20 STD-PRT-04 / Danger Plates 25 21 ED-04-035 Fig.4/ HV Cable box, for 11kV Transformer- All Sizes 26 22 ED-04-035 Fig.5/ LV Cable Box & Bushing assembly up to 1600KVA 27



1) SCOPE

1) This specification details about the requirements for design, manufacture, testing, transporting, and delivery of 11/0.433KV Cast Resin (Dry Type) distribution transformers, intended for use on public electric supply system in the State of Qatar.

2) The transformers shall be two winding, cast resin, natural air cooled (without any forced ventilation) with metallic enclosure, and connected through bushings in cable boxes.

3) The transformers are intended to be installed in Indoor Applications, in non-air

conditioned rooms. These transformers need to withstand the harsh ambient and climatic conditions prevailing in the state of Qatar, as specified in subsequent sections.

4) The rated capacities of the transformers shall be 500KVA, 1000KVA & 1600KVA for

continuous service at 50 Hz to transform energy from 11kV (nominal) to 415/240V(nominal).

2) ENVIRONMENTAL CONDITIONS

The following conditions prevail throughout in the State of Qatar

1) Altitude - low lying, generally close to sea level, no part exceeding 100m above sea level.

2) Maximum air temperature 50oC ( 46oC typical).

3) Minimum air temperature 0oC ( 10oC typical)

4) Mean maximum summer air temperature, 45oC typical.

5) Mean maximum exposed sunlight temperature, 75oC

6) Solar radiation- peak, 1030 Watts/sq.m.

7) Humidity - 100% humidity is common throughout the year and may occur at air temperature of 30oC or more.

8) Rainfall - very low on average. The winter season may bring infrequent very heavy rainfall.

9) General atmospheric conditions: A hot atmosphere containing very fine, highly penetrating dust particles. In parts the atmosphere contains a highly corrosive salt laden sea mist. Prevailing winds generally from the north west, mostly light but occasionally gusting in excess of 30 knots

3) SYSTEM CONDITIONS

The 11kV system has three phase, 3-wire system with star point earthed through earthing transformer at 66/11KV primary sub-station.

1) Nominal Voltage ....................................................................11kV

2) Maximum Voltage .................................................................12kV

3) Maximum Symmetrical fault level ..............................................25KA/31.5kA (based on location in the network)

4) Limited earth fault current through earthing transformer…....4.5KA



5) Impulse Voltage.....................................................................75kV

6) Rated Frequency ...................................................................50 Hz

The LV System has 5 wires i.e. 3 Phase + Neutral + Earth. Neutral and earth is directly shorted at the Distribution Substation end. A consumer earth terminal is provided.

7) Nominal Voltage.................................................................. 415/240V

8) Highest Symmetrical fault level............................................44kA

9) The highest fuse rating(at LV Distribution Feeder Pillars).....400 A

Fault duration is limited by HRC fuses, Type-J to BS 88 (at LV Distribution Feeder Pillars). 4) APPLICABLE STANDARDS

This Specification makes reference to the following documents: Transformers IEC 60076-11 Dry type Power Transformers. IEC 60076 Power Transformers IEC 60076-10 Power Transformers – Determination of Sound Levels.. IEC 60905 Loading guide for Dry Type Power Transformers. BS 2562 Specifications for Cable Boxes for Transformers, Flanges, Bushings BS 6435 Un-filled enclosure for dry termination of HV Cables for transformers Surface Preparation, Coating & painting Works ISO 8501-1 to 4 Preparation of Steel Substrates before application of paints and related products. ISO 8502-1 to 12 Preparation of Steel Substrates before application of paints and related products –

Tests for assessment of surface cleanliness. ISO 8503-1 to 5 Preparation of Steel Substrates before application of paints and related products -

Surface Roughness Characteristics of Blast-Cleaned Steel Substrates ISO 8504-1 to 3 Preparation of Steel Substrates before application of paints and related products –

Surface preparation methods. ISO 12944-1 to 8 Corrosion Protection of Steel structures by protective paint systems ISO 14713 Protection against Iron & Steel Structures – Zinc and Al coatings – Guide lines BS 381C 1980 Specification for Colours for Identification, Coding, and Special Purposes. BS EN ISO 1460 Hot Dip Galvanized Coatings on Ferrous metals – Gravimetric determination BS EN ISO 1461 Hot Dip Galvanized Coatings on Ferrous metals- Specification & test methods ISO 2081 Electro-plated coatings of zinc with supplementary treatments on iron or steel ISO 2063 Thermal spraying- Zinc, aluminum and their alloys BS 2569-2 Sprayed Metal Coatings – Protection of Iron & Steel against Corrosion ISO 4628-1 to 5 Evaluation of Degradation of paint coatings ISO 9227 Salt spray test ISO 1519 Paints & Varnishes – Bend test ISO 2808 Paints & Varnishes – Determination of film thickness ISO 2409 Paints & Varnishes – Cross cut test ISO 1520 Paints & Varnishes – Cupping test ISO 6272 Paints & Varnishes – Rapid deformation (Impact resistance) test



ISO 6270 Paints & Varnishes – Determination of resistance to humidity ISO 11997 Paints & Varnishes – Determination of resistance to cyclic corrosion conditions ISO 7784 Paints & Varnishes – Determination of resistance to abrasion Other Common Standards IEC 60529 Degrees of Protection Provided by Enclosures – IP Code IEC 62262 Degrees of Protection Provided by Enclosures – IK Code ISO 3864 Graphical symbols, Safety labels, Safety colours & Safety Signs IEC 60502 XLPE Power Cables Fasteners BS 3692 ISO Metric Precision Hexagonal Bolts, Screws and Nuts. BS 4190 ISO Metric Black Hexagonal Bolts, Screws and Nuts. ISO 4042 Fasteners – Electroplated coatings ISO 888 Bolts, Screws and Studs - Nominal Lengths, and Thread Lengths for GP Bolts

5) GENERAL DESIGN FEATURES

1) The design, construction & testing of Cast-resin transformers shall be generally in accordance with IEC 60076-11, unless other-wise specified. Cable boxes, mounting flanges, bushings shall generally conform to the respective standards mentioned above, unless other-wise specified.

2) The transformer shall be fitted inside sheet steel enclosure having IP protection degree of IP31 with natural air ventilation.

3) The Transformer or its Enclosure shall not be fitted with any forced ventilation or exhaust fans. Only the natural air ventilation available in the civil building room shall be able to provide necessary ventilation needs.

4) The manufacturer needs to provide necessary calculations for air flow requirements and sizing details of indoor civil room construction for cooling of transformer with natural ventilation.

5) The transformers shall be capable of delivering full rated power continuously, under specified service and ventilation conditions, without any thermal overloading. The design & construction of transformer shall be such that, no de-rating factor shall need to applied on account of specified temperature rise limits, enclosure IP protection, and ventilation requirements.

6) The no-load LV output voltage of the transformers shall be 433/250V, when HV side is applied with 11kV at center tap. This is to provide consumers with a nominal supply voltage of 415/240V (three phase 4 wire/Single phase 2 wire, 50Hz) on full load, after permitted system voltage drops.

7) The sub-assemblies of the transformer shall be so designed that they should not un-duly increase the vibrations or cause resonance. Anti-vibration mounts shall be incorporated to reduce vibration & noise levels.



6) RATINGS & CHARACTERISTICS

1) Service conditions & maximum winding temperature rise limits

a) Average of hottest month temperature of cooling air outside enclosure is 350C

b) The maximum temperature of cooling air outside enclosure may exceed 500C any time

c) The relative Humidity surrounding the transformer may reach 100%

d) Frequent Condensation may occur during high humid conditions

e) The surrounding air may contain very fine, highly penetrating, sand dust with highly corrosive salt laden sea mist.

f) The maximum temperature rises of the windings shall not exceed by 850K over an ambient temperature of 500C, when fully loaded inside in the specified enclosure, without forced ventilation.

2) Ratings

a) Rated Power of Transformers : 500KVA/1000KVA/1600KVA

b) IP protection of Enclosure : IP31

c) IK protection of Enclosure : not less than IK7 (2.0 joules)

d) Ventilation : Natural air cooling-AN (no forced ventilation)

e) Th. Insul. class of windings(HV/LV) : Class F/F

f) Winding material (HV/LV) : CU/CU

g) Voltage ratio : 11000/433V

h) No. of phases : 3-Phase

i) Connections : Delta- Star, as per vector group Dyn11

j) Rated frequency : 50HZ

k) Rated voltage (U) : 11kV

l) Maximum flux density : ≤ 1.6 Tesla at normal voltage and frequency

m) No-load current : ≤ 1% of transformer rated current

n) Tapping range & steps : +5% to -5%, in 4-steps each of 2.5%

o) Rated Insulation Levels

Parameter Name HV Side LV Side Rated Voltage(U) 11KV 433/250V (at no load) Rated Highest Withstand Voltage(Um) 12kV 1.1kV Rated Lightening Impulse Withstand Voltage (peak) 75kV -

Rated Power frequency withstand voltage 28kV 3kV



p) Guaranteed values of losses (load & no-load), percentage impedances measured at principal tap and corrected to reference temperature of 750C shall be as mentioned below.

KVA Rating Max. No-load losses* Max. Load Losses* % Impedance

500KVA 1050 5100 4.75 ±10% 1000KVA 1650 8800 5.45 ±10% 1600KVA 2200 12500 6.00 ±10% *Note: The values specified for No-load & load losses are maximum values.

q) The climatic class of the transformers shall conform to: Class C1 r) The Environmental class of the transformer shall conform to: Class E2

s) The Fire behavior class of the transformer shall conform to: Class F1

t) Maximum dimensional limits of Enclosure: 2300 (L) x 1500 (W) x 2300 (H), mm

u) IP protection of HV & LV Cable boxes: IP43

3) Short Circuit Ratings

Verification of transformer’s ability to withstanding short-circuit conditions, shall be made through type testing in accordance with IEC 60076-5, at reputed independent laboratories.

a) Thermal ability of the transformers to withstand short circuit current shall be verified for a duration of 2 sec. The value of ambient temperature shall be considered as not less than 500C for calculation of initial winding temperature.

b) Ability to withstand dynamic effects of short circuit shall be verified by tests (not by calculation method)

4) Tapping Range & Tapping Method

a) Off-circuit tapping selection shall be made by the use of bolted links on the HV winding. The tapping range shall be ±5% in steps of ±2.5% For total 5 tap positions.

b) Current carrying capacity of the bolted links for tapping shall be capable of withstanding the rated short-circuits capacity.

5) Magnetic flux density

a) The flux density at any point of the magnetic circuit when the transformer is connected on normal tap (3) and operating at normal voltage and frequency shall not be more than 1.6 Tesla, and well below the saturation level. Proof of this shall be submitted for verification in the form of B/AT magnetizing curves of the magnetic core assembly

6) Thermal insulation Class of windings & temperature rise limits

a) Thermal insulation class of HV & LV windings shall conform to the class-F/F (Insulation system temperature - 1550C) as defined on IEC 60085.

b) The maximum temperature rises of the windings shall not exceed by 850K over an ambient temperature of 500C, when fully loaded the transformer inside the specified sheet steel enclosure with natural ventilation, without forced cooling.



7) Noise (Sound) Levels

a) Verification shall be done by conducting type test, through reputed independent

laboratory, for sound level measurements in accordance with IEC 60076-10 under indoor conditions.

b) The maximum values of sound pressure and sound power levels, measured at a distance of 1 meter from the ‘principal radiating surface’, are as mentioned below:

Parameter Details Unit Maximum values 500 KVA 1000 KVA 1600KVA

Average ‘A-weighted’ sound pressure level LpA dB(A) 54 57 60

Calculated ‘A-weighted’ sound power level LwA dB(A) 67 71 75

8) Climatic, environmental and fire behavior classes

a) Special tests for climatic, environmental and fire behavior classes shall be carried out as per the tests specified in clauses# 26, 27 and 28 of IEC 60076-11 in a reputed independent testing laboratory.

b) A transformer is considered to be passed these tests, when all the prescribed tests are conducted on same transformer in the sequence as given in table-5 of IEC 60076-11.

c) The climatic class of the transformers shall conform to: Class C1

d) The Environmental class of the transformer shall conform to: Class E2

e) The Fire behavior class of the transformer shall conform to: Class F1

7) RATING AND CONNECTION PLATES - MARKING OF TERMINALS

1) Rating and Connection Plates (as per IEC 60076-11/Cl-9)

Each Transformer, as well as the associated enclosure, shall be fitted with individual rating plates of weather-proof materials, in a visible position, showing all the items indicated below. The entries on the plate shall be indelibly marked (that is, by etching, engraving, stamping, or by a photo-chemical process) a) Dry-Type transformer b) Compliance standards reference c) Manufacturer Name d) Manufacturer’s serial number e) Month & Year of manufacture f) KM Contact/Tender number g) Insulation system temperature of each winding h) Number of phases i) Rated frequency j) Rated voltage including tapping voltages k) Rated current l) Connection symbol m) Short circuit impedance at 750C n) Type of cooling



o) Insulation Levels p) Degree of Protection q) Environmental class r) Climatic class s) Fire behavior class t) Total mass with and without enclosure

2) Marking of Terminals & start of windings

a) HV and LV Terminals shall be identified by characters of a type which cannot be obliterated, marked on plates of durable and non-corrodible metal securely fixed to a visible position. Stickers are not acceptable

b) The sequence of markings on HV terminals when read from left-to-right, facing HV cable box, shall be as: A, B, C

c) The sequence of markings on LV terminals when read from left-to-right, facing LV cable box, shall be as: c, b, a, n

d) Suitable markings to identify the start and end of windings shall be marked on each physical winding.

8) GENERAL CONSTRUCTION AND FITTINGS

1) Magnetic Core & connecting bus bars

a) The magnetic core shall be constructed from high grade, low watt loss, cold rolled grain oriented silicon steel sheets, having specific watt loss of not more than 0.95w/kg at 1.7T and 50Hz, and conforming to IEC 60404-8-7:2008 and IEC 60404-1: 2000.(Note: 1.7T is used only for the purpose of comparing the grade, but actual design of transformer shall be made for 1.6T)

b) The construction of yoke and limbs shall be such that best space factor and highest dimensional accuracy is achieved to ensure low core losses and nose levels.

c) The core shall be coated with high performance surface insulation material(s), conforming to the requirements of IEC 60404-11, to obtain good insulation resistance and anticorrosion protection.

d) The clamping structure shall not allow any bolt piercing the core lamination in order to avoid circulating current in the core and local concentration of the flux in the yoke

e) The limb & yoke core joints shall be interleaved using modern step-lap technology to achieve optimum conformity of magnetic flux pattern.

f) The core shall be pressed and banded and shall be clamped and bolted at the top and bottom in such a manner as to ensure that no distortion shall take place when the transformer is subjected to magneto motive forces equivalent to those which would be present in the event of a total short circuit being applied across the low voltage terminal with an infinite power supply at normal voltage and frequency available, at the high voltage terminals.

e) All bus-bars shall be made of hard drawn high purity electrolytic copper with electro-tin plating.



2) Windings

a) The HV windings of the transformers shall be made of high purity electrical grade copper wire and shall be totally encapsulated in a glass-fiber reinforced resin-cast insulation. The casting shall be made under vacuum in such a manner that all air shall be totally evacuated from casting.

b) The casting shall be such that the composite structure shall have sufficient resilience strength against stresses developed due to differences in co-efficient of thermal expansions between insulation materials and copper.

c) Laying pattern of HV winding wires shall ensure to achieve superior linear lightening voltage distribution characteristics.

d) LV windings shall be made of copper foil with impregnated type interlayer insulation. The interlayer insulation shall be made of solid polyester foil with impregnated fiber glass film which thermo-sets by curing, or by an equivalent process having same or higher performance levels.

e) Sufficient numbers of cooling channels shall be provided in both the LV and HV windings to restrict the temperature rise of the windings within the specified values and thereby minimizing the damage due to hot spot. The cooling channels are arranged in a vertical manner and all coils have even surface to minimize dust accumulation and to give maximum cooling efficiency.

f) The completed winding stack assembly and connections shall have sufficient mechanical rigidity to ensure no distortion or movement of any one winding, or to any other winding or section of windings, shall take place when the transformers is subjected to the short circuit stresses created by a total short circuit at the low voltage terminals with an infinite power supply at normal voltage and frequency available for two seconds at the high voltage terminals.

g) Sufficient barriers shall be provided between windings and core, and between HV and LV windings.

h) The winding insulation shall be such that the transformer may be operated at 155° C with no deterioration of the insulation properties as per IEC 60076-11 requirements. It shall comply with the requirements of Class F/F insulating materials.

i) The high voltage and low voltage connections shall be brought out on opposite sides of the transformer

j) The windings shall be connected Delta Star in accordance with Vector Group reference Dyn11.

k) All leads or bars from windings to the termination points, shall be rigidly supported. Stresses on coils and connections must be avoided.

l) The insulation materials used on windings and connections shall be shall be free using any insulating compounds prone to shrinking or collapse during service life. Further, there shall not be any joints either in the LV foil or insulation.



3) Enclosure

a) The Transformer shall be contained in a sheet steel ventilated enclosure suitable for indoor service. The overall limiting dimensions of the enclosure and fittings attached there-in shall not exceed the values specified below:

- Length: 2300 mm - Width : 1500 mm (excluding cable boxes) - Height: 2300 mm.

b) The enclosure degree of protection shall not be less than IP 31 including its bottom surface. If so desired, number of ventilation louvers may be increased to take care of ventilation requirements.

c) All side panels (covers) and top of the enclosure shall be removable type using standard metric spanners. No handles or other aids shall be employed for easy removal of panels. All bolts & nuts shall be non-corrosive stainless steel/alloy steel.

4) Fittings & Accessories: The following accessories are required to be fitted on the transformer:

a) Earthing Terminal

Two stainless steel earthing flags, of size 63x63mm , and 6mm thick each, having hole suitable for connecting M14 bolt, or an equivalent arrangement shall be provided at bottom of the transformer frame work on either side. All exposed metallic conductive non-live parts shall be connected to earth terminals by construction through full earth fault rated conductors/braids.

b) Lifting Lugs on Total assembly

The transformer with enclosure assembly shall be fitted with two lifting lugs enabling lifting of transformer and enclosure assembly. The position of the lugs facilitates easy attachments of lifting slings. The transformer shall be suspended absolutely vertical when it is lifted by means of the lifting hooks.

c) Lifting (hoist) eyelets on transformer (active part)

Four lifting (hoist) eyelets shall be provided on all four corners (one at each corner) of upper press-beams/clamp-bars of the transformer, to facilitate lifting of transformer alone (without enclosure) when required.

d) Haulage holes on under base

Four haulage holes shall be provided on all four corners of lower press-beam/clamping-bar (one at each corner).

e) Bi-directional rollers at base

Four bi-directional flat rollers with blocking facilities (as mentioned below) are to be fitted at base of the transformer, on to which entire load of transformer & enclose assembly shall be transmitted.

f) Anti-vibration pads and Roller blocking devices

Anti-vibration pads made of polycarbonate material, having capability of carrying loads of the transformer & enclosure, shall be provided at base to dampen the intensity of



vibrations and avoid resonance. They should also serve as roller blocking devices to arrest the movement of transformer unit after installation.

g) Rating & Connection Plate, and colour coding

Rating and connection diagram plates with details as described in clause # 5.1 shall be provided both on transformer and enclosure. Colour coding (Red, Yellow & Blue), with indelible markings, shall be provided at suitable locations on the frame of active part, to identify phase of each core, and inside cable boxes to identify phases of HV & LV terminals.

h) Danger Boards

Danger Boards, prepared as per KM specification # ED-01-400 (Drg # STD-PRT-04) shall be fixed permanently on all four sides of the enclosure. [Note: Removable labels or stickers are not acceptable]

i) Viewing Window

A transparent viewing window, of 6 inch x 4 inch size, with 5mm thick clear polycarbonate sheet shall be fitted on enclosure at front, to view the tapping position of transformer. This fixture shall have IP 65 protection with necessary gasket(s).

j) Chart of tap-changing link positions

A chart showing the combination of links positions for each tap position shall be permanently fitted on enclosure at front. The details on the chart shall be indelibly marked by etching, or engraving, or stamping, or by photo-chemical process (Note: stickers are not acceptable)

k) Temperature monitoring unit for thermal protection

1) At least 2 sets of PT100 based, high accuracy, RTD type PTC Temperature sensors shall be embedded into to each phase of LV winding.

2) The sensors & its associated wiring shall be insulated, to avoid occurrence of any short circuits with the transformer winding. The sensors shall be placed as close as possible to the hottest spot in the winding.

3) The insertion of sensors shall be made through capillary tube to enable them to be replaced whenever necessary.

4) The first set of the sensors shall be set to give ‘alarm signal’ at 1400C, and the second set shall be set to give ‘trip signal’ at 1500C. These values shall be in conformity with Class F insulation.

5) The ‘alarm’ and ‘trip’ signals shall be in the form of voltage free relay output contacts. Each output relay contacts shall have at least 2NO+2 NC and each rated for 6A@240Vac.

6) The temperature monitoring unit (i.e Electronic converter with relays and wiring terminal block) shall be capable of operating in the specified local ambient conditions. It shall be flush mounted on front side of the enclosure. The unit shall be capable of operating on 240Vac @50Hz power supply.

7) The monitoring unit shall have features of circuit-fault indication, storage of maximum value of temperature, live voltage indication, status of relay positions with different coloured light indications, reset facility, etc.

8) The power supply for the monitoring unit shall be connected from transformer LV output (240Vac, 1-Phase) through suitably rated terminal blocks. The terminal



block shall have additional spare terminals, to facilitate connecting external power source (auxiliary source), when required.

9) All wiring, to and fro, from the temperature monitoring unit shall be routed through properly clamped and insulated trunking-channels. No wires shall be left loose or hanging inside the enclosure.

10) The monitoring units shall not cause any false tripping. It shall be sourced from reputed brands and its source and technical details to be submitted along with tendering information.

l) Thermometer.

1) In addition to the temperature monitoring unit as described above, a dial type

thermometer, having nominal dia of 100mm, with stainless steel bezel and casing, shall be fitted on the transformer (not on enclosure) with suitable sensing element. The thermometer shall indicate the temperature of the winding and maximum temperature.

2) Its dial shall be graduated in degrees Centigrade and cover the range 0°C to 160°C with increment marks at not more than 5°C intervals. The dial shall be fitted with pointers to indicate the winding temperature, and maximum temperature value with a RED pointer. The maximum temperature pointer shall be manually re-settable. The thermometer shall be located in a safe and suitable place to have clear view.

5) Corrosion protection and Painting of Enclosure.

1) The definitive guideline documents are BS EN ISO 12944 Parts #1 to 8, & BS EN ISO 14713. The painting procedure selected by the manufacturer should clearly indicate its relationship to the appropriate parts and tables of BS EN ISO 12944 and BS EN ISO 14713

2) It is the responsibility of the manufacturer to assess environmental classification, select suitable surface preparation process, protective paint system, execution and supervision process, in accordance with above referred standards and requirements.

3) The painting work should render a service life of at least 20 years to the equipment, withstanding local ambient climatic & environmental conditions.

4) The exact Specification & painting procedure going to be followed by the manufacturer shall be submitted at time of tender.

5) The manufacturer should posses required laboratory testing equipment, in their factory, to test the painting work samples in accordance with BS EN ISO 12944-6. The test reports should be submitted along with each consignment of delivery.

6) The paint work shall nee to pass following tests a) Measurement of thickness of protective coating (ISO 2808) b) Specular gloss factor at 60 deg (ISO 2813): 90±5% c) Falling weight test (ISO 6272): 1kg/50cm d) Cross cut test (ISO 2409): classification: 0 e) Cupping test (ISO 1520): 08mm f) Bending test – Cylindrical mandrel test (ISO 1519): 3.0mm g) Salt spray (fog) test (ISO 7253): 1000hrs



6) Cable Boxes

1) Cable boxes shall be in accordance with the relevant Drawings no ED/04-035 Fig 1 and Fig 2 generally comply with the requirements of BS 2562 and, where applicable BS 6435. The details are as explained in APPENDICES-A, B & C.

2) High Voltage and low voltage cable boxes shall be mounted on opposite sides of the transformer.

3) HV & LV Cable boxes shall be suitable for vertical bottom entry of cables. However LV cable box shall also have suitable facility (in addition to this bottom cable entry) for top entry bus-bar connections, when required. [Note: Bus-connections shall be made through cable box only, they should not be made through top of enclosure directly]

4) The bushing heights of HV and LV shall be 1320 mm from the enclosure base to centre of bushings assembly.

5) The construction shall be such that the accumulation of water is avoided and the box is effectively sealed against weather and insects

6) The minimum size of any fixing stud or bolt for securing a front cover plate shall be M10 mild steel. All bolts used in assembly of cables boxes or enclosure shall be electroplated for corrosion protection

7) Gaskets, where applicable shall be of nitrile rubber-bonded cork and shall not be less than 5mm thick. [Note: Neoprene based cork gaskets are not to be used]

9) QUALITY CONTROL

The manufacturer of the equipment specified shall possess certification, issued by a body authorized to do so, which indicates that the manufacturing unit operates to a standard equivalent to ISO 9001. Copies of valid ISO 9001 certificates need to be submitted along with tender documents.

10) TESTS

1) General a) At the time of tender, manufacturers shall submit copies of test certificates, as prescribed

below, issued from reputed independent testing laboratories. All type tests & special tests are to be carried out on representative specimen transformers essentially of the same design & ratings.

b) KM reserves the right to verify the original test certificates & reports, if required.

c) Special tests for climatic, environmental and fire behavior classes shall be carried out as per the tests specified in clauses# 26, 27 and 28 of IEC 60076-11. A transformer is considered to be passed these tests, when all the prescribed tests are conducted on same transformer in the sequence as given in table-5 of IEC 60076-11.

d) Each transformer shall be subjected to all routine tests prescribed below, and one set of routine test report shall be attached with the body of transformer in a strong water-proof envelope, at the time of delivery.



2) Type Tests & Special Tests on Transformer.

a) Lightning Impulse test (type test) as per IEC 60076-3. b) Temperature Rise test (type test) as per IEC 60076-2. c) Partial discharge tests (routine & special tests) as per IEC 60076-11/Cl-22 d) Measurement of sound level (special test) as per IEC 60076-10 e) Short circuit test (special test) as per IEC 60076-5 f) Environmental test (special test) g) Climatic test (special test) h) Fire behavior test (special test)

3) Routine Tests on Transformer.

a) Measurement of winding resistance.(IEC 60076-11/Cl-15) b) Measurement of voltage ratio and check of phase displacement (IEC60076-11/Cl-16). c) Measurement of short-circuit Impedance and load loss(IEC 60076-11/Cl-17) d) Measurement of no load loss and current (IEC 60076-11/Cl-18) e) Separate source AC withstand voltage test(IEC 60076-11/Cl-19) f) Induced AC withstand voltage test(IEC 60076-11/Cl-20). g) Routine partial discharge test (IEC 60076-11/Cl-22.4.1.1) h) Transformer Noise level Test at 1meter distance. i) Check of vector group by voltmeter method j) Measurement of Insulation resistance of LV winding at 2500V, DC k) Over-voltage test at 2000V, AC, for 60sec, on secondary wiring & equipment l) Measurement of thickness of painting work

11) TESTING, INSPECTION & DELIVERY

1) Before commencing the production/manufacturing of 1st lot, against KM tenders, the manufacturer is obliged to produce samples of Transformer with enclosure and inform Kahramaa for inspection and acceptance through witnessing factory acceptance tests, and routine tests.

2) For every subsequent lot, the manufacturer is obliged to inform Kahramaa, at least 20 days before dispatch, and obtain clearance for dispatch. KM Engineers have the option of inspecting & witnessing all factory acceptance tests (FAT), including routine tests, at manufacturer’s factory premises for each lot.

3) Acceptance by KM Engineer(s)/Representative(s) of any Transformer shall not relieve the manufacturer from any of their responsibilities, guarantees, or from other obligations, to manufacture the product fully complying with KM specification.

4) Type tests are to be carried out on specimen Transformer with enclosure, essentially of same design and ratings, as being offered. Manufacturer is obliged to provide details of test procedures being followed, to the KM inspection team before commencing factory accepting tests.

5) Each Transformer unit need to be subjected to all routine tests at factory before delivery. Further, each unit may be subjected to inspection on receiving them at DOHA to verify its healthiness and its conformity with the guaranteed design data.



6) All tests should be performed in accordance with the latest issue of relevant IEC standards

7) Three sets (copies) of routine tests & FAT reports to be prepared. One set to be attached with the body of transformer enclosure, in a strong water-proof envelope. Second copy to be sent along with delivery note. Third copy to be sent to the end-user department.[This is mandatory requirement]

8) FAT report shall include copy of ‘quality control report’ containing ‘list of check points’ verified/inspected at factory against each transformer.

9) Each delivery note shall include the details of ‘serial number’ and ‘month/year’ of production of each transformer.

10) Both the manufacturing date (i.e month/year) and delivery date should be shown on the rating plate of each transformer, and the time difference between manufacturing date and delivery date should not be more than 6-months.

12) INFORMATION/DOCUMENTS TO BE SUBMITTED BY BIDDERS/MFRS

Each manufacturer/bidder shall submit following information/documents along with their offer

. At least two sets of documents with all details to be submitted.

1) Technical data-sheets covering all the details as mentioned below.

a) Rated power b) Rated Voltage ratio, Frequency, & number of phases c) Rated insulation levels d) IP protection class of enclosure e) IK protection class of enclosure f) Type of ventilation g) Vector group h) Thermal insulation class of HV/LV winding i) Maximum flux density j) No-load current and full load current values k) Tapping range and number of steps l) No-load and Load losses at 750C m) Percentage impedance value at 750C n) Winding material HV/LV o) Guaranteed values of Winding temperature rise limits p) Partial discharge levels q) Noise levels r) Climatic, Environmental & Fire behavior classes s) Weights of transformer with and without enclosure and fittings t) Overall sizes(WxHxD) of transformer with and without enclosure u) Set values of ‘alarm’ and ‘trip’ in temperature monitoring unit. v) Resistance values of HV & LV windings

2) The following drawings need to be submitted

a) Transformer general layout drawing with enclosure (all views plan, elevation, side elevation) showing details of all components fitted and all dimensions.



b) Transformer general layout drawing without enclosure (all views plan, elevation, side elevation) showing details of all components fitted and all dimensions.

c) Separate HV cable box drawing with all views and dimensions d) Separate LV cable box drawing with all views and dimensions e) Separate HV bushing drawing with all views and dimensions f) Separate LV cable box drawing with all views and dimensions g) Connection diagram showing the sequence of HV & LV+ neutral terminals h) Rating plate details i) HV & LV terminal connection details j) HV & LV cable boxes mounting flange drawings with dimensions

3) Other details and documents which need to be submitted

a) Original product catalogue (photocopy not acceptable) with all technical details including all steps of manufacturing.

b) Original product catalogue of temperature monitoring unit (photo copy not acceptable) c) Installation, Operation & Maintenance, and condition monitoring & trouble shooting

manuals, of transformer d) Installation, Operation & Maintenance manuals of temperature monitoring unit e) Ventilation calculations with room sizing and air flow requirements f) FAT documents& check lists used for testing of transformers at factory

4) Copies of test reports to be submitted

Type test reports (full reports) a) Lightning Impulse test b) Temperature Rise test conducted along with enclosure c) Partial discharge tests (routine & special tests) d) Measurement of sound level (special test) e) Short circuit test (special test) f) Environmental test (special test) g) Climatic test (special test) h) Fire behavior test (special test) i) Type testing report of HV bushing

Routine test reports

a) Measurement of winding resistance. b) Measurement of voltage ratio and check of phase displacement c) Measurement of short-circuit Impedance and load loss d) Measurement of no load loss and current e) Separate source AC withstand voltage test f) Induced AC withstand voltage test g) Routine partial discharge test

Test reports of Enclosure painting work

a) Measurement of thickness of protective coating (ISO 2808) b) Specular gloss factor at 60 deg (ISO 2813): 90±5% c) Falling weight test (ISO 6272): 1kg/50cm d) Cross cut test (ISO 2409): classification: 0



e) Cupping test (ISO 1520): 08mm f) Bending test – Cylindrical mandrel test (ISO 1519): 3.0mm g) Salt spray (fog) test (ISO 7253): 1000hrs

5) Statement of Compliance / deviation

A statement of compliance or deviation against each clause of this specification document needs to be submitted. This is very important document, without which the offer documents shall not be considered.

13) WARRANTY Manufacturers need to provide a warranty of minimum 5 years from the date of delivery, or 4 years from the date of installation (whichever is earlier) against each unit supplied.

Any Transformer unit failed while in service, with-in the warranty period, need to be replaced with new unit free of cost. Further, the manufacturer/supplier need to arrange for carrying-out fault/abnormality analysis of any units(s) by reputed independent agencies, when required by Kharamaa and respective abnormality and fault-analysis report(s) to be submitted

14) DEVIATIONS FROM THE TECHNICAL SPECIFICATION The bidders are required to attach a separate deviation list to their Technical Offer and include it in the Technical Package if the offered equipments do not meet the requirements of any clause of the Specification.

Offers without any deviation list attached to the Technical Offer and included in the Technical Package shall mean that the offer meets the requirements of the Specifications on all the clauses.

Offers with deviations listed out shall mean that the offer meets the requirements of the Specification on all the other clauses not included in the deviation list.

15) RESTRICTIONS ON OUT-SOURCING

1) Out sourcing of any of main components (like magnetic core assembly, making winding coils, casting of coils, fabrication of enclosure, paint work, etc) related to transformers, need to be declared in the beginning it- self, before the transformer is pre-qualified or short listed for tenders. In the event of out-sourcing any of these components, the transformer manufacturer is responsible for quality of such components and paint work, and need to produce all documentary evidences as to how they control quality of these components.

2) If any changes proposed by the manufacturer at later stage (after pre-qualification or short-listing in tenders) in sourcing of these main components or accessories, shall need to be informed to and obtain KM approval before the changes are made. Non-compliance of this condition may lead to rejection of goods.



APPENDIX A

High Voltage Cable Boxes for all Sizes of Transformers

1) The high voltage cable box shall be in accordance with the requirements of Drawing No. ED/04-035 Fig 4 and generally be in accordance with BS 2562:1979, and where applicable, BS 6435.

2) It shall be air filled and suitable for using heat-shrink terminations with cable entry from

bottom.

3) The HV bushings shall be of the porcelain type of rating 250 Amps, in accordance with Fig 3 of BS 2562:1979. However similar rated bushings, made of porcelain material, conforming to IEC 60137 is also permissible, provided its surface profile and terminal connection shall be suitable for terminating with KM standard Right-Angled Boot type heat shrinkable cable termination kits.

4) A brass wiping gland shall be provided in accordance with Fig 32(Size-Y) of BS 2562:1979

suitable for terminating 3 core 70-120 sq.mm XLPE insulated PVC sheathed steel wire armoured cable to IEC-60502. An armour clamp also shall be provided to fix armour wires from cable.

5) The cable gland shall not be insulated from the cable box.

6) The cable box shall be designed for cables entering vertically from below, and to permit ease

of access for jointing and connecting the cable it shall be so constructed that the cable can be introduced into the box without threading, with the cores cut to length and the gland and plate located on the cable sheath. For this purpose, the bottom plate, with gland, shall be detachable.

7) IP protection class of the cable box shall be IP43. Two Breathing holes covered with wire

gauze shall be made in the cable box as shown, the degree of protection being IP43. The same shall apply to a hole situated on the bottom plate of the box, the purpose of which is to drain condensate.

8) The HV cable box shall be mounted on enclosure wall through a flange facing "E" in

accordance with Fig 24 of BS 2562:1979.

9) The minimum clearances of live metal in air shall be as follows: Between Phases -- 127 mm Between Phases and earth -- 127 mm



APPENDIX B Low Voltage Cable Terminations and Cable Box for Transformers in the range

500/1000kVA

1) The LV Cable Box shall be in general accordance with BS 2562:1979 and, in particular Fig 30 (unfilled boxes) and Fig 16 (cast resin bushings). The arrangement and dimensional requirements of the attached Drawing ED-04-035 Fig-5 is mandatory.

2) The box shall be un-filled type, air insulated, and suitable for connecting, a) bottom entry

cable termination, or b) top entry bus-bar connections. If necessary the box may be so constructed that it may be made of two horizontally split boxes to meet this requirement.

3) The cable box shall be of Shell Type 114, as defined in Table 11 of BS 2562 (except as may

be modified by Drawing ED-04-035 Fig 2) and its mounting on to the transformer enclosure shall be through flange connection conforming to ‘flange facing Type F of BS 2562.

4) Three 12mm diameter breathing holes covered with fine wire gauze shall be made

equidistant along the stepped underside of the box. The degree of protection shall be IP43. The same shall apply to a hole situated on the bottom plate of the box, the purpose of which is to drain condensate.

5) To accommodate bottom entry of the cables, removable bottom plate shall be provided. The

bottom plate shall have holes diameter for glands to be minimum 70 mm each.

6) The cables will be single core, stranded compacted copper conductor, up to 630 sq. mm, XLPE insulated, PVC Inner sheath, and copper wire armoured, PVC over-sheath to IEC 60502. There shall be two cables per phase. Terminations will be by heat shrink techniques.

7) Seven numbers of Brass wiping glands conforming to size-X of BS 2662 shall be

fitted at bottom of the gland plate. Armour clamps shall be provided to each gland.

8) The low voltage bushing shall be of the cast resin assembly type for use up to 1.1kV, as shown in Fig 16 of BS 2562: 1979. The bus-bars shall be of high conductivity electrolytic copper and all bus-bar lengths, including that of neutral shall be same.

9) The cable cores shall be connected to the bushing bus-bars using 4 hole compression lugs as

per the cable size shown in Table B3.

10) The minimum clearances of live metal in air shall be: Between Phases -- 26mm Between Phase and earth -- 20mm

11) Drawings shall be submitted for approval at tender stage.



APPENDIX C Low Voltage Cable Terminations and Cable Box for 1600 KVA Transformers

1) The low voltage Cable Box shall be in general accordance with BS 2562:1979 and, in particular Fig 30 (unfilled boxes) and Fig 16 (cast resin bushings). The arrangement and dimensional requirements of the attached Drawing ED-04-035 Fig-2 is mandatory

2) The box shall be un-filled type, air insulated, and suitable for connecting, a) bottom entry cable termination, or b) top entry bus-bar connections. If necessary the box may be so constructed that it may be made of two horizontally split boxes to meet this requirement

3) The cable box shall be of Shell Type 114, as defined in Table 11 of BS 2562 (except as may be modified by Drawing ED-04-035 Fig 5) and its mounting on to the transformer enclosure shall be through flange connection conforming to ‘flange facing Type F of BS 2562

4) Three 12mm diameter breathing holes covered with fine wire gauze shall be made equidistant along the stepped underside of the box. The degree of protection shall be IP43. The same shall apply to a hole situated on the bottom plate of the box, the purpose of which is to drain condensate

5) To accommodate bottom entry of the cables, removable bottom plate shall be provided. The bottom plate shall have holes diameter for glands to be minimum 70 mm each.

6) The cables will be single core, stranded compacted copper conductor, up to 800 sq. mm, XLPE insulated , PVC Inner sheath, and copper wire armoured, PVC over-sheath to IEC 60502. There shall be two cables per phase. Terminations will be by heat shrink techniques

7) Seven numbers of Brass wiping glands conforming to size-X of BS 2562 shall be fitted at bottom of the gland plate. Armour clamps shall be provided to each gland

8) The low voltage bushing shall be of the cast resin assembly type for use up to 1.1kV, as shown in Fig 16 of BS 2562: 1979 (except as may be modified by Drawing ED-04-035 Fig 5, and the thickness of bus-bar shall be 20mm). The bus-bars shall be of high conductivity copper and lengths of all bus-bars including that of neutral shall be same.

9) The cable cores shall be connected to the bushing bus-bars using 4 hole compression lugs as per the cable size shown in Table B3

10) The minimum clearances of live metal in air shall be: Between Phases -- 26mm Between Phase and earth -- 20mm

11) Drawings shall be submitted for approval at tender stage.



TABLE B1 (Details of Cable boxes)

S.No Description HV Box LV Box

1 Rated Voltage 12kV 1.1kV

2 No of Poles 3 4

3 No of Glands 1 7

4 Gland Size Size-Y, BS: 2562 Size-X, BS: 2562

5 Size of Cables 3Cx70-120mm2 1Cx300 to 630mm2 up to 1000KVA

1Cx800mm2 for 1600KVA

6 Bushing Assembly 250A - porcelain 1700A for 500/1000KVA

2500A for 1600KVA

7 Bushing Type Porcelain as per Fig.3, BS: 2562 Cast resin assembly as per Fig.16 BS 2562

8 Type of Cable CU/XLPE/SWA/PVC to IEC-60502 CU/XLPE/CWA/PVC to IEC-60502.

9 Type of Box Dry type, un-filled using heat shrink terminations.

Dry type, un-filled using heat shrink terminations.

10 Cable entry Vertically from below Vertically from below

11 Mounting flange Face flange- E Face Flange -F

12 Box shell No - 114

TABLE-B2 (Minimum clearances in the cable boxes)

Voltage Live metal to earth Distance, mm

Phase to Phase Distance, mm Distance to earth over surface of bushing, mm

433V 20 26 26 11kV 127 127 76

TABLE-B3(No & Size of Cable in LV Cable Box) Transformer Rating No. of LV Cables Size of LV Cables sq.mm

500 KVA 7 1Cx300 mm2

1000 KVA 7 1Cx630 mm2

1600 KVA 7 1Cx800 mm2

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