manufacturing , testing , supply , erection and commissioning of 3 nos . 20 mva , 11/132kv generator transformers for mukerian hydel project , talwara , punjab ( 2 nos . ) and ubdc hydel project , malikpur , pathakot , punjab ( 1 no . ) . manufacturing , testing , supply , erection and commissioning of 3 nos . 20 mva , 11/132kv generator transformers for mukerian hydel project , talwara , punjab ( 2 nos . ) and ubdc hydel project , malikpur , pathakot , punjab ( 1 no . ) . , part i : supply , 20 mva , 11/132kv , onan cooled , oil immersed outdoor type generator transformer suitable for 3-phase , 50 c/s frequency , delta-star connected in accordance with iss vector group yd 11 with neutral solidly earthed on hv side . the transformer will be fitted with off ckt tap changer of easun-mr/ telk/ bhel/ ngef/ cgl/ ctr/ paragon associates/ alwaye make type 66 kv , 300 amps rating for voltage variation on hv side to give 142 . 5 kv , 139 kv , 135 . 5kv , 132 kv and 128 . 5 kv with lv constant . percentage impedance on 20 mva base at 75 deg . c shall be as 10% + tolerance as per is-2026 part-ii latest edition . the transformer shall be able to operate continuously for 10% overload capacity . the transformer shall be dispatched oil filled . transformer oil ( napthenic base ) for radiators& conservators etc . alongwith 10% extra quantity shall be dispatched directly in non-returnable epoxy coated steel drums . the transformer shall be complete with all fittings and accessories as per specification . the following extra spares with each transformer shall form part of supplies . , hv line end bushing complete , lv line end bushing complete , hv neutral end bushing complete , complete sets of gaskets , wti with remote indicator , magnetic oil level gauge , oti with remote indicator , silica gel container along with silicagel ( for one time filling ) for main tank , pressure relief valve , buchholz relay , dial type thermometer for oti , switches , fuses , relays for electric control ckt . , short circuit test charges for 1 no . gt ( if applicable ) , part ii : erection and commissioning , erection , commissioning of 20 mva , 11/132kv , onan cooled , oil immersed outdoor type generator transformer .