Rakesh Nath - CEA

1 Rakesh NathChairperson, central ElectricityAuthority & Ex officio SecretaryGovernment of IndiaForewordThe objective of National electricity Policy is Power to all by 2012 . To achive this, about78500 MW of generation capacity and matching Transmission and Distribution systems are to beadded during 11th Plan. This would entail addition of about lakh MVA of DistributionTransformer capacity during the Plan. Stringent quality control has to be ensured right from selectionof raw materials, manufacturing to procurement and installation of these transformers. The Distribution utilities have generally been procuring transformers with maximum allowablelosses as per IS1180. With the advent of more efficient materials and improvement in technology,it is now possible to have much more efficient and better quality transformers at reasonable specifications for single phase and three phase outdoor oil filled Distribution Transformershave been prepared by the central electricity Authority to act as Guidelines for the utilities forselection and procurement of energy efficient Transformers.

2 The specifications have been finalizedafter detailed discussions with the Distribution utilities and the manufacturers of DistributionTransformers. This has been possible through the concerted efforts of engineers in the Distribution Planning& Development Division of central electricity Authority. I hope the Guidelines will be of immenseuse for the engineers in the Power Distribution utilities. ( Rakesh Nath)Member GO&DCentral electricity AuthorityEx-officio Additional SecretaryGovt. of IndiaPrefaceReforms in the Distribution sector have got a big boost with the implementation of theAccelerated Power Development and reform programme of Govt. of India. Distributiontransformers form a very vital and substantial part in the delivery supply chain and large number oftransformers are being procured by the utilities under this programme as well as with their ownresources to meet the GOI mission of Power for all by 2012.

3 Recognising the importance ofstandardization of specifications of the distribution transformer for procurement of qualitytransformers, the central electricity Authority has formulated technical Specifications for Threephase and single phase oil filled outdoor type Distribution transformers. The document has been prepared after discussions and considering inputs from the variousstakeholders of the Power Distribution industry viz power utilities, manufacturers and Bureau ofEnergy Efficiency. The document is intended to provide Guidance for preparing technical part ofthe tender document for procurement of Distribution specifications are the result of the concerted efforts of Sh. Alok Gupta Chief EngineerDP&D and Smt.

4 Anjuli Chandra Director (Distribution) and other officers of Distribution Planning& Development Division. ( Dhiman)Sl. FOR OUTDOORS TYPETHREE PHASE OIL IMMERSED (INCLUDINGCOMPLETELY SELF PROTECTED) 01 DISTRIBUTION TRANSFORMERS 11 kV/433 250V and 33 kV FOR OUTDOOR TYPESINGLE PHASE OIL IMMERSED (INCLUDING 55 COMPLETELY SELF PROTECTED) DISTRIBUTIONTRANSFORMERS 11 kV/230 V and 11/ 3 kV/230 FOR OUTDOOR TYPE THREE PHASE OIL IMMERSED (INCLUDING COMPLETELYSELF PROTECTED) DISTRIBUTION TRANSFORMERS OF 11 kV/433 250V and 33 kV for non preparation and self protected (CSP)

5 Management signal tests to be conducted on one at and testing of transformer assurance and -IMethodology for computing total owning cost29 Annexure -IIProforma for stage inspection of distribution30transformersAnnexure -IIIP roforma for pre-delivery inspection of41distribution transformersAnnexure -IVSource of meterial / places of manufacture,47testing and inspectionSchedule-IAGuaranteed and other particulars for distribution48transformersSchedule-IBAdd itional details52 CONTENTSSPECIFICATION FOR OUTDOOR TYPE SINGLE PHASE OIL IMMERSED (INCLUDINGCOMPLETELY SELF PROTECTED) DISTRIBUTION TRANSFORMERS 11 kV/230 V and 11/ 3 kV/230 V .Clause for non preparation and and terminal release kv lightning load capacity6821 Protection.

6 (for CSP transformers) tests to be conducted on one at assurance and for computing total owning cost76 Schedule IAGuaranteed technical particulars for completely77self protected distribution transformersSchedule IBAdditional details79 Schedule IIBS ource of materials/places of manufacture,80testing and inspectionSTANDARD TECHNICAL SPECIFICATIONFOROUTDOOR TYPE THREE PHASE OIL IMMERSED(INCLUDING COMPLETELY SELF PROTECTED)DISTRIBUTION TRANSFORMERS11 kV/433-250 VAND33 kV/433-250 V11/ 3 kV/230 V1 TECHNICAL SPECIFICATION FOR OUTDOOR TYPEDISTRIBUTION TRANSFORMERS 11 kV/433 250 Vand 33 kV / 433-250V1 specification covers design, engineering, manufacture, assembly, stagetesting, inspection and testing before supply and delivery at site of oil immersed,naturally cooled 3 phase 11 kV/433 - 250 V and 33 kV/433-250 V distributiontransformers for outdoor is not the intent to specify completely herein all the details of the design andconstruction of equipment.

7 However the equipment shall conform in all respectsto high standards of engineering, design and workmanship and shall be capableof performing in continuous commercial operation, in a manner acceptable tothe purchaser, who will interpret the meanings of drawings and specificationand shall have the power to reject any work or material which, in his judgment isnot in accordance therewith. The offered equipment shall be complete with allcomponents necessary for their effective and trouble free operation. Suchcomponents shall be deemed to be within the scope of bidder s supplyirrespective of whether those are specifically brought out in this specificationand / or the commercial order or transformer and accessories shall be designed to facilitate operation,inspection, maintenance and repairs.

8 The design shall incorporate everyprecaution and provision for the safety of equipment as well as staff engagedin operation and maintenance of outdoor apparatus, including bushing insulators with their mountings, shallbe designed so as to avoid any accumulation of standard ratings shall be 10, 16, 25, 63, 100, 160, 200, 250, 315, 400,500, 630, 1000, 1250, 1600, 2000 and 2500 kVA for 11 kV distributiontransformers and 100, 160, 200, 315, 400, 500, 630, 1000, 1250, 1600, 2000,2500 kVA for 33 kV distribution materials shall conform in all respects to the relevant Indian/InternationalStandards, with latest amendments thereof unless otherwise specified of them are listed below.

9 2 IndianTitleInternational andStandardInternationallyrecognisedstan dardsIS -2026 Specification for Power TransformersIEC 76IS - 1180 Outdoor distribution Transformer up to andincluding 100 kVAIS 12444 Specification for Copper wire rodASTM B-49IS-335 Specification for Transformer OilBS 148, D-1473,D-1533-1934 IEC Pub 296IS - 5 Specification for colors for ready mixed paintsIS - 104 Ready mixed paint, brushing zinc chromate, primingIS 2099 Specification for high voltage porcelain bushingIS - 649 Testing for steel sheets and strips andmagnetic circuitsIS - 4257 Dimensions for clamping arrangementsfor bushingsIS - 7421 Specification for Low Voltage bushingsIS - 3347 Specification for Outdoor BushingsDIN 42531 to 33IS - 5484 Specification for Al Wire rodsASTM B - 233IS - 9335 Specification for Insulating Kraft PaperIEC 554IS - 1576 Specification for Insulating Press BoardIEC 641IS - 6600 Guide for loading of oil Immersed TransformersIEC 76IS - 2362 Determination of water content in oil forporcelain bushing of transformerIS - 6162 Paper covered aluminium conductorIS - 6160 Rectangular Electrical conductor for

10 ElectricalmachinesIS - 5561 Electrical power connectorIS - 6103 Testing of specific resistance of electricalinsulating liquidsIS - 6262 Method of test for power factor and dielectricconstant of electrical insulating liquidsIS - 6792 Determination of electrical strength of insulating oilIS - 10028 Installation and maintenance of conforming to other internationally accepted standards, which ensureequal or better quality than the standards mentioned above, would also beacceptable. In case the bidders who wish to offer material conforming to otherstandards, the bidder shall clearly bring out the salient points of differencebetween the standards adopted and the specific standards in relevant copies of such standards with authentic English translations shall befurnished along with the Distribution Transformers to be supplied against this Specification shallbe suitable for satisfactory continuous operation under the following climaticconditions as per IS 2026 (Part - I).