Pole Mounted Distribution Transformers

TECHNICAL SPECIFICATIONPOLE MOUNTED DISTRIBUTION TRANSFORMERS  INTRODUCTIONThis specification provides for the design, manufacture, testing in factory, supply, delivery and off-loading on site for Pole Mounted Distribution Transformers.It shall be the responsibility of the Contractor to furnish equipment, which shall meet in all respects the performance specification and will have satisfactory durability for the prevailing site conditions.The Contractor shall furnish all material and labour not herein specifically mentioned or included, but which may be necessary to complete any part of the work or work as whole, in compliance with the requirements of this specification.The detailed design arrangement of the equipment shall be the responsibility of the Contractor subject to the approval of the Engineer. The design and workmanship shall be in accordance with the best engineering practices to ensure satisfactory performance throughout the service life.The Pole Mounted Distribution Transformers supplied shall also fully comply with the General Service and System Conditions  Standards and CodesExcept where modified, all equipment and materials shall be in full accordance with IEC (International Electrotechnical Commission) and ISO (International Standards Organisation) standards and recommendations. If relevant IEC or ISO standards and recommendations are not available in any case or cases then relevant British Standards or National Standards shall apply if available.When IEC, ISO, BSI or National Standards are referred  to  the  edition  used  shall  be  that current at the date of Tender, together with any amendment issued to that date.Further to that above additional standards order of preference is listed below: IECInternational Electrotechnical CommissionISOInternational Standards Organisation BSIBritish StandardsNS National Standards (where available) ANSI American National Standards InstituteWhere the use of a standard other than IEC, ISO or BSI is agreed then this standard shall be used, where applicable. Where other standards are proposed in place of IEC, ISO or BSI Standards, confirmation shall be provided that the provisions of the standards are equivalent to or exceed those of the equivalent IEC, ISO or BSI standards.Copies of any standards proposed in substitution for  IEC,  ISO  or BSI standards  must be submitted with  the Tender accompanied where necessary by English translations of the appropriate sections.  Notwithstanding any descriptions, drawings or illustrations which may have been submitted with the Tender, all details other than those shown in the 'Deviation from the Technical Specification Schedule' and approved by the Engineer shall be deemed to be in accordance with the Specification and the standard specifications and codes referred to therein.No departures from the specification except those shown in the 'Deviation from the Technical Specification Schedule' and approved by the Engineer are to be made without the written approval of the Engineer.The Pole Mounted Distribution Transformers shall comply with the latest editions of and amendments to, the standards/specifications listed below:  S.No.STANDARDTITLE1.IEC 60137Insulated bushings for AC Voltages above 1 kV2.IEC 60076-1Power Transformers - General3.IEC 60076-2Temperature rise4.IEC 60076 - 3Insulation levels, dielectric tests and external clearances in air5.IEC 60076 -5Ability to withstand short6.IEC 60076 - 7Loading guide for oil immersed transformers7.IEC 60296Specification for unused mineral insulating oils for transformers and switchgear8.IEC 60076 - 10Determination of transformer and reactor sound levels9.IEC 60437Radio Interference Test on High Voltage Insulators10.IEC 296-1969, IEC 76Specification for power transformers11.IEC 296-1969Bushing for alternating voltage above 1000V12.DIN 42531 to 33Specification for Outdoor Bushings.13.ASTM D-1275Specification for fittings and accessories for powertransformers14.IEC 76Guide for loading of oil immersed Transformers15.BS 159:1957BS 3288 (Part-1):1960Electrical power connector16.IEC 554Specification for Insulating Kraft Paper17.IEC 641Specification for Insulating Press Board18.ASTM B-233Specification for Al Wire rods19.ASTM D-1275Manual on Transformer20.ASTM D-202Testing of Insulation Papers21.ISO 2063Metallic Coatings - Protection of Iron and Steel againstCorrosionPRODUCT  Design  Types of transformersThe transformers shall be three phase or single phase units of the sealed tank type with oil immersed copper windings and shall be naturally cooled (ONAN). They shall be suitable for operation in outdoor exposed locations.Performance characteristics  RatingThe following ratings are covered by this Specification: THREE PHASE:33/0.400/0.230kV - 25kVA, 50 kVA, 100 kVA and 200 kVASINGLE PHASE: The single phase transformers shall be connected on the primary side between two phases of 3-phase lines33kV/230 V-0-230 V - 10 kVA, 15 kVA, 25 kVA and 50 kVA  Transformer rated kVA shall be calc