PART 1 - GENERAL
1.01 DESCRIPTION
A. This section cover the manufacturer, furnish, install and test all equipment, accessories and materials required for the installation of oil-immersed power transformer in accordance with specifications and drawings. Any material or equipment necessary for the proper operation not specified or described herein shall be deemed part of the specifications.
1.02 APPLICABLE CODES AND STANDARDS
A. The work shall be carried out in accordance with this specification, the contract drawings and the standards listed hereunder.
The following codes and standards provide an acceptable level of quality for materials and products:
1. SASO Saudi Arabian Standards Organization.
2. IEC 60076-1 Power transformers
to 60076-5
3. IEC 60354 Loading guide for oil-immersed type power transformers.
4. CENELEC Harmonisation Documents:
- HD 398-1 to 398-5: 1980 + A3 1986 for power transformers
1.03 QUALITY ASSURANCE
A. All materials and products shall be new, sound and uniform in quality, size, shape, color and texture and shall be free from defects.
B. The contractor shall be responsible for ensuring that the required standards of quality control as mentioned in relative sections are maintained for the proposed transformer.
C. If requested by the client, the supplier shall provide proof of application of a quality procedure complying with standards. This means:
1. use of a quality manual approved and signed by a management representative,
2. regular updating of this manual so that it reflects the most recent applicable quality control procedures,
3. ISO 9002 certification.
D. The manufacturer must have a sound experience in the field of transformers for not less than ten years, and should have a presentable reference list of the already supplied equipment of the same type and same make and that this equipment has been in satisfactory operation in Kingdom of Saudi Arabia for at least three years.
1.04 SUBMITTAL
A. Shop Drawings and Manufacturer's Data:
The contractor shall submit to the client/client representative for review, detailed dimensioned shop drawings and manufacturer's literature where deviations from the contract drawings or specification exist. Shop drawings and/or data sheets shall be based on information stated in the specifications and as shown on the contract drawings and shall show all pertinent deviations and data for the fabrication and complete installation.
Manufacturer's data sheets shall be submitted indicating the necessary installation dimensions, weights, materials and performance information. The above information may be provided by standard catalogue sheets marked to indicate the specific items provided.
B. Operation and Maintenance Instructions:
The contractor shall furnish data covering model, type and serial numbers, capacities, maintenance and operation of each major item of equipment or apparatus in accordance with the requirements of the contract documents. Operating instructions shall cover all phases of control.
C. Test Reports:
The contractor shall submit test reports to the client/client representative for review.
D. Recommended Spare Parts List:
The contractor shall submit recommended spare parts list to the client/client representative for review.
E. As Built Drawings:
The contractor shall submit the as built drawings to the client/client representative for review and approval.
1.05 COORDINATION
A. The contractor shall be held responsible for the proper coordination of all phases of the work under this contract.
B. It shall be the responsibility of the contractor to coordinate the work and equipment as specified herein with work to be performed and equipment to be furnished under other sections of the specifications in order to assure a complete and satisfactory installation.
1.06 PRODUCT DELIVERY, STORAGE AND HANDLING
A. Deliver, store, protect and handle products to site as per manufacturer’s instructions.
B. Store transformers in clean and dry space. Inspect for damage. Maintain factory wrapping or provide an additional heavy canvas or heavy plastic cover to protect units from dirt, water, construction debris and traffic.
C. Lift only with lugs provided for the purpose. Handle carfully to avoid damage to transformers internal components, enclosure and finish.
PART 2 - PRODUCTION
2.01 GENERAL
A. The following specifications apply to three-phase oil-immersed transformers, hermetically sealed with integral filling, insulation system with oil natural air natural (ONAN) cooling for indoor or outdoor installation destined for use in three-phase MV/MV distribution systems.
2.02 GENERAL REQUIREMENTS
A. Magnetic Core
1. This shall be made from laminations of grain oriented silicon steel, insulated with mineral oxide; the method of cutting and stacking shall be "step lap", so as to optimise the level of no-load losses.
B. Windings
1. These shall be made from copper profile wire or aluminium or copper foil (according to the manufacturer's preference).
C. MV Connections
1. The standard MV connections shall use porcelain bushings on the transformer.
2. Fixed MV plug-in bushings, with MV mobile plug-in bushings - straight or elbow according to the orientation of the incoming cables - may be provided if specified in the other documents.
D. Tapping
1. The tapping which act on the highest voltage adapting the transformer to the real supply voltage value, shall be provided with an off-circuit tap-changer switch with a padlocking facility on the top cover of the transformer.
2.03 MAIN CHARACTERISTIC OF CONSTRUCTION
A. Tank
1. The tank of the transformer shall be made with flexible cooling corrugations, in order to absorb the expansion of the dielectric due to temperature variations.
2. The cover shall be bolted on top of the tank.
3. The tank shall be built in such a way as to avoid any water accumulation.
B. Dielectric and Component Material
1. The dielectric shall be mineral oil, class I & II according to IEC 60296.
2. The concentration in PCB has to be lower than the minimum detection rate of 2 ppm (parts per million).
3. The components of the transformer such as insulation material, varnish, painting, etc. have to be new and PCB-free.
4. The filling of the transformer shall be made under vacuum, in order to guarantee the maximum preservation of dielectric properties.
5. The live part of the transformer shall be previously oven dried so as to remove all residual humidity.
C. Gaskets
1. All the gaskets shall be resistant against the action of the mineral oil, at the working temperature.
D. Protection Against Corrosion
1. The anticorrosion treatment of the tank and the cover shall comprise:
- An external degreasing and rinsing
- A hot phosphating operation
- A powdering through application of a polyester resin with an electrostatic spray gun (minimum thickness 40 to 50 microns)
- Final colour green grey RAL 7033
2. The main characteristics of the coating guarantee:
- A gloss of 30 to 60 % for an angle of 60° (measured according to ASTM-D523)
- A salt spray resistance of 1000 hours (measured according to ASTM-B117)
- A UV resistance without losses more than 10% gloss according to the RAL scale 1 (measured according to NFT 30-057, over a 3 months period).
- An adherence of between 0 and 1 (measured according to ASTM-D3359)
2.04 ACCESSORIES AND STANDARD EQUIPMENT
A. The transformers shall be equipped with:
1. 4 bi-directional flat rollers
2. 2 lifting and untanking lugs
3. 2 earthling terminals
4. 1 filling plug
5. 1 draining device
6. 1 rating plate
7. 1 "Danger Electricity" warning label
8. 1 routine tests certificate
9. 1 instruction manual for installation, commissioning and maintenance in English.
B. Protection
1. The transformers shall be equipped with a DGPT2 protection relay including:
- 1 gas detector/flow level indicator with one contact (for gas discharge and drop in liquid level)
- 1 over pressure contact (for internal pressure increase)
- 2 thermostats for alarm and tripping (for internal temperature increase)
- 1 dial type thermometer without contact.
2.05 ROUTINE AND TYPE TESTS
A. Routine Tests
The following tests shall be carried out on all the transformers after the manufactu¬ring, enabling an official test certificate to be produced for each one:
1. Measurement of windings resistance.
2. Measurement of the transformation ratio and vector group
3. Measurement of impedance voltage and load loss
4. Measurement of no load loss and no load current
5. Applied voltage dielectric test
6. Induced voltage dielectric test
(All these tests shall be in accordance with IEC 60076-1 to 60076-5 standards).
B. Type Tests and Special Tests
The following tests may be requested (if mentioned in the documents):
1. Temperature rise test.
2. Lightning impulse test.
3. Short circuit test.
4. Noise level measurements in accordance with IEC 60551.
5. Measurement of partial discharges.
(All these tests shall be in accordance with IEC 60076-1 to 60076-5 standards).
C. The manufacturer shall produce a test report from an official laboratory on a transformer of the same design as those produced.
Transformer Technical Data
• Type Hermetically sealed
• Rated power as shown on the drawings
• Cooling ONAN
• Standard IEC 60076 and SASO
• Thermal Class A
• Max. ambient temperature 50 Degree C
• Dielectric Mineral oil
• Dielectric temperature rise 50 Degree C
• Winding temperature rise 55 Degree C
• Max. altitude 1000 m
• Vector Group Dyn11
• Winding material Copper
• Primary voltage 13.8 KV or 33 KV or as required
• MV rated voltage 17.5 KV or 36 KV or as required
• Power-frequency withstand voltage 38 KV/70 KV
• Impulse withstand voltage - peak 95 KV/170 KV
• MV tapping range (off-voltage) +/ - 2.5 % +/- 5 %
• Secondary No-load voltage as required
• Frequency 60 HZ
• Rated impedance voltage as required
• MV Terminals Porcelain/Plug-in
PART 3 - EXECUTION
3.01 WORKMANSHIP
A. Materials, products and equipment furnished by the contractor, shall be installed and all work shall be performed in a first-class workmanship manner, in conformity with the best trade practices and the printed directions of the applicable manufacturers; by skilled workers equipped to produce satisfactory results; in a safe, substantial manner so as to avoid undue stresses, rigid enough to prevent undue movement, so as to present a neat, orderly appearance and to facilitate operating, servicing, maintenance and repairing.
3.02 FOUNDATIONS AND SUPPORTS
A. The contractor shall provide concrete pedestals, anchor bolts, hangers, channels, saddles, etc., for installation of equipment and apparatus shown on the drawings and specified in the various sections.
3.03 EQUIPMENT ERECTION
A. All electrical equipment shall be installed in accordance with the manufacturer's recommendations, good electrical engineering practice, and the relevant drawings and specifications.
B. All metal surfaces to be bolted shall be thoroughly cleaned before assembly. The connections shall be tightened with manual torque wrenches to the manufacturer's erection instructions.
3.04 EQUIPMENT TESTING AND COMMISSIONING
A. After the installation is complete and properly adjusted, the contractor shall conduct operating tests. The various equipment and systems shall be demonstrated to operate in accordance with the requirements of the contract documents. Tests shall be performed in the presence of the client/client representative. The contractor shall provide electric power, instruments and personnel necessary for performing the various tests.
B. The testing of all electrical equipment shall include, but not be limited to, the items below. This shall be in addition to testing specified elsewhere in this specification.
1. General equipment check.
2. Field wiring and ground system verification.
3. Equipment adjustment.
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