SPECIAL REPAIR/ REPLACEMENT OF BER TRANSFORMER AND CONNECTED ACCESSORIES AT SUB STN-II AFMSD KANDIVALI UNDER GE (N), SANTACRUZ MUMBAI

Supply, fixing , testing and commissioning of AC 3 phase, 50 Hz, 200 KVA capacity transformer, step down, indoor type 11000 / 433 volts ( at no load ) with system voltage 12KV all as per IS 1180 ( Part- I ) : 2014 copper wound, oil immersed, naturally cooled with external cooling tubes, ONAN cooling core type, delta connected on primary ( HV ) side and star connected on secondary ( LV ) side in accordance with vector symbol DYN-11 ( Vector Group ) with neutral brought on secondary ( LV ) side & having tapings in equal steps of 2.5% from ( + ) 7.5% to ( - ) 7.5% on primary side by means of hand operated off load tap changing gear, so as to change / correct LT voltage on secondary side including provision of all necessary / standard fittings all as per latest & IEC 76 latest amendments and of level 3 transformer as per IS 1180 ( Part-1 ) : 2014 complete all as specified and as directed comprising of the following accessories :-

(a) The core shall be stack / wound type of high grade Cold Rolled Grain Oriented or Amorphous Core annealed steel lamination having low loss and good grain properties coated with hot oil proof inter layer insulation of Nomex / Epoxy dotted Kraft Paper, bolted together and to the frames firmly to prevent vibration or noise. The core shall be stress relieved by annealing under inert atmosphere if required. The complete design of core must ensure permanency of the core loss with continuous working of the transformers. LV winding shall be such that neutral formation will be at top. Current density for HV and LV winding should not be more than 2.8 Ampere per sqmm. (b) The maximum allowable losses at 75° C for 11 / 0.433 kV at 50% of rated load and total losses at 100% of rated load shall not exceed the maximum total loss 416 watts and 1281 watts respectively without any positive tolerance all as per specified in IS- 1180 ( Part- 1 ): 2014 for energy efficient rating 5 star. (c) The percentage impedence of transformers at 75° C for 200 KVA shall be as per Table 6 of IS- 1180 ( Part-1 ) : 2014 (d) Transformer tank construction shall confirm in all respect to clause 15 of IS- 1180 ( Part-1 ): 2014. The internal clearance of tank shall be such that it shall be such, that it shall facilitate easy lifting of core with coils from the tank without dismantling LV bushings. All joints of tank and fittings shall be oil tight and no bulging should occur during service. Inside of tank shall be painted with varnish / hot oil resistant paint. The top cover of the tank shall be slightly sloping to drain rainwater. The tank plate and the lifting lugs shall be of such strength that the complete transformer filled with oil may be lifted by means of lifting shackle. Manufacturer should carry out all welding operations as per the relevent ASME standards. The transformer tank shall be of robust construction and shall be built up of electrically tested welded mild steel plates of thickness of 6mm from the bottom and top and not less than 4mm for the sides for distribution transformers with Tolerance as per IS-1852. The space above oil level in the tank shall be filled with dry air or nitrogen confirming to commercial grade of IS- 1747. The tank shall further be capable of withstanding a pressure of 0.8 kg / sqcm and a vacuum of 0.7 kg / sqcm (g) without any deformation.

(e) Audible sound levels for 200 KVA, 50 Hz oil immersed distribution transformers shall be 56 decibels ( NEMA Standards). (f) One cable box on primary HV side having cable glands suitable for 95 Sqmm x 3 core XLPE 11 KV H.T cable consisting of 3 Nos procelain H.T bushings with brass / gun metal bushing rods confirming to IS- 2099 and IS- 3347 for outdoor bushing complete with nuts and washers. HT cable box should prevent the ingress of moisture into the box due to rain water directly falling on the box. The cable box on HT side shall be of the split type with faces plain and machined and fitted with Neo-k-Tex or similar quality gasket and complete with brass wiping gland to be mounted on separate split type gland plate with nut-bolt arrangement and MS earthing clamp. The bushings of the cable box shall be fitted with nuts and stem to take the cable cores without bending them. The stem shall be of copper with copper nuts. The cross section of the connecting rods shall be stated and shall be adequate for carrying the rated currents. On the HV side the terminal rod shall have a diameter TS for 3 Phase DT 11 of not less than 12mm. The material of connecting rod shall be copper. HT cable support clamp should be provided to avoid tension due to cable weight. (g) One cable box on secondary ( LV ) side consisting of 4 Nos procelian bushings complying to IS- 7421 with GM bushing rods complete with GM nuts, and washers with cable gland suitable for reception of outgoing LT PVC sheathed armoured cables of size 2 x 300 Sqmm x 3.5 core, having non-magnetic material gland plate with appropriate sized single compression brass glands on LV side to terminate 1.1 KV / single core XLPE armoured cable. (h) The bushing rods and nuts shall be made of brass material 12mm diameter for both HT and LT bushings. The bushings shall be fixed to the transformers on side with straight pockets and in the same plane or the top cover. The tests as per latest IS- 2099 and IS- 7421 shall be conducted on the transformer bushings.

( j ) Oil Conservator : The provision of conservator is mandatory with oil gauge, air release plug and breathing device with a drain plug and a filling hole 32mm ( ¼ " ) normal size thread with cover. The dehydrating agent shall be silica gel. The moisture absorption shall be indicated by a change in the colour of the silica gel crystals which should be easily visible from a distance. The total volume of conservator shall be such as to contain 10% quantity of the oil. Normally 3% quantity the oil shall be contained in the conservator. (k) The Radiators can be tube type or fin type or pressed steel type to achieve the desired cooling to limit the specified temperature rise. (l) Transformer to be painted with poly urethane / powder coated ( colour light grey / smoke grey ) paints over anti-corrosive primer & shall be free from runs, sags, wrinkles, patchiness, brush makrs or other defects. All primers shall be well marked into the surface, particularly in areas where painting is evident and the first priming coat shall be applied as soon as possible after cleaning. (m) One No. 100mm dia dial type thermometer vapor pressure type having range 0 - 120 degree centigrade with temperature reading pointer, max temperature indicator and re-settling device. (n) Rating plate with terminal markings. (o) Two earthing terminals on tank / tank cover to facilitate fixing of 32 x 6mm GI earthing strip. (p) Lifting lugs

(q) Four plane solid cast steel detachable rollers. (r) First fill of fresh transformer Oil confirming to IS-355, BS148, D-1473, D-1533 - 1934IEC Pub 296 and tested upto 50 KV dielectric strength. Use of recycled oil is not acceptable. (s) Extra bushing for neutral outside the LT cable box for providing independent earthing for neutral. (t) Provision of 2 Nos danger boards 250 x 200 mm size made out of 1.6mm thick MS plate, vitreous enamelled white, with letters, figures of voltage and conventional skull and bones in signal red colour, one at HT side and other on LT side. (u) Any other fittings / accessories so as to conform the whole transformer to IS-1180 ( Part-1 ) : 2014, Amendment - 4 of March 2021. Note : The quoted rate must include dismantling existing Transformer and taking out from substation bldg and handing over to MES store yard at AGE E/M Office Santacruz..- 4 )

Material and labour for Earthing complete with Galvanised steel earth plate electrode 60 cm x 60 cm x 6 mm thick, buried directly in ground (earth pit not less than 2.25 metres deep below normal ground level) with top edge of earth the plate not less than 1.5 metres below normal ground level, connected to plate with GI earth strip 32 x 6mm, 7.5 m long from earth point to test point and other end connected to control board / panel / equipment, laid under floors / plinths or fixed on walls or concealed in wall etc by means of bolts, nuts, check nuts and washers made out of galvanised iron or steel with provision of charcoal & common salt packed upto minimum 150 mm all around the earth plate and protected by 40 mm bore light grade galvanised iron pipe complete all as shown in electrical plate No.3 of MES schedule Part I, 2009 with PCC pit in PCC 1:2:4 type B1 using 20 mm graded stone aggregate, MS angle iron frame of size 50mm x 50mm x 5mm, cast iron cover with locking arrangements, GI 15 mm bore medium grade pipe and CI funnel with wire mesh for watering arrangement including necessary excavation and earth work in any type of soil/strata & testing complete all as specified and as directed by Engineer-in-Charge.

Supply, fixing , testing and commissioning of AC 3 phase, 50 Hz, 250 KVA capacity transformer, step down, indoor type 11000 / 433 volts ( at no load ) with system voltage 12KV all as per IS 1180 ( Part- I ) : 2014 copper wound, oil immersed, naturally cooled with external cooling tubes, ONAN cooling core type, delta connected on primary ( HV ) side and star connected on secondary ( LV ) side in accordance with vector symbol DYN-11 ( Vector Group ) with neutral brought on secondary ( LV ) side & having tapings in equal steps of 2.5% from ( + ) 7.5% to ( - ) 7.5% on primary side by means of hand operated off load tap changing gear, so as to change / correct LT voltage on secondary saide including provision of all necessary / standard fittings all as per latest & IEC 76 latest amendements and of level 3 transformer as per IS 1180 ( Part-1 ) : 2014 complete all as specified and as directed comprising of the following accessories :-

(a) The core shall be stack / wound type of high grade Cold Rolled Grain Oriented or Amorphous Core annealed steel lamination having low loss and good grain properties coated with hot oil proof inter layer insulation of Nomex / Epoxy dotted Kraft Paper, bolted together and to the frames firmly to prevent vibration or noise. The core shall be stress relieved by annealing under inert atmosphere if required. The complete design of core must ensure permanency of the core loss with continuous working of the transformers. LV winding shall be such that neutral formation will be at top. Current density for HV and LV winding should not be more than 2.8 Ampere per sqmm. (b) The maximum allowable losses at 75° C for 11 / 0.433 kV at 50% of rated load and total losses at 100% of rated load shall not exceed the maximum total loss 416 watts and 1281 watts respectively without any positive tolerance all as per specified in IS- 1180 ( Part- 1 ): 2014 for energy efficient rating 5 star. (c) The percentage impedence of transformers at 75° C for 250 KVA shall be as per Table 6 of IS- 1180 ( Part-1 ) : 2014 (d) Transformer tank construction shall confirm in all respect to clause 15 of IS- 1180 ( Part-1 ): 2014. The internal clearance of tank shall be such that it shall be such, that it shall facilitate easy lifting of core with coils from the tank without dismantling LV bushings. All joints of tank and fittings shall be oil tight and no bulging should occur during service. Inside of tank shall be painted with varnish / hot oil resistant paint. The top cover of the tank shall be slightly sloping to drain rainwater. The tank plate and the lifting lugs shall be of such strength that the complete transformer filled with oil may be lifted by means of lifting shackle. Manufacturer should carry out all welding operations as per the relevent ASME standards. The transformer tank shall be of robust construction and shall be built up of electrically tested welded mild steel plates of thickness of 6mm from the bottom and top and not less than 4mm for the sides for distribution transformers with Tolerance as per IS-1852. The space above oil level in the tank shall be filled with dry air or nitrogen confirming to commercial grade of IS- 1747. The tank shall further be capable of withstanding a pressure of 0.8 kg / sqcm and a vacuum of 0.7 kg / sqcm (g) without any deformation.

(e) Audible sound levels for 250 KVA, 50 Hz oil immersed distribution transformers shall be 56 decibles ( NEMA Standards). (f) One cable box on primary HV side having cable glands suitable for 95 Sqmm x 3 core XLPE 11 KV H.T cable consisting of 3 Nos procelain H.T bushings with brass / gun metal bushing rods confirming to IS- 2099 and IS- 3347 for outdoor bushing complete with nuts and washers. HT cable box should prevent the ingress of moisture into the box due to rainwater directly falling on the box. The cable box on HT side shall be of the split type with faces plain and machined and fitted with Neo-k-Tex or similar quality gasket and complete with brass wiping gland to be mounted on separate split type gland plate with nut-bolt arrangement and MS earthing clamp. The bushings of the cable box shall be fitted with nuts and stem to take the cable cores without bending them. The stem shall be of copper with copper nuts. The cross section of the connecting rods shall be stated and shall be adequate for carrying the rated currents. On the HV side the terminal rod shall have a diameter TS for 3 Phase DT 11 of not less than 12mm. The material of connecting rod shall be copper. HT cable support clamp should be provided to avoid tension due to cable weight. (g) One cable box on secondary ( LV ) side consisting of 4 Nos procelian bushings complying to IS- 7421 with GM bushing rods complete with GM nuts, and washers with cable gland suitable for reception of outgoing LT PVC sheathed armoured cables of size 2 x 300 Sqmm x 3.5 core, having non-magnetic material gland plate with appropriate sized single compression brass glands on LV side to terminate 1.1 KV / single core XLPE armoured cable. (h) The bushing rods and nuts shall be made of brass material 12mm diameter for both HT and LT bushings. The bushings shall be fixed to the transformers on side with straight pockets and in the same plane or the top cover. The tests as per latest IS- 2099 and IS- 7421 shall be conducted on the transformer bushings.

( j ) Oil Conservator : The provision of conservator is mandatory with oil gauge, air release plug and breathing device with a drain plug and a filling hole 32mm ( ¼ " ) normal size thread with cover. The dehydrating agent shall be silica gel. The moisture absorption shall be indicated by a change in the colour of the silica gel crystals which should be easily visible from a distance. The total volume of conservator shall be such as to contain 10% quantity of the oil. Normally 3% quantity the oil shall be contained in the conservator. (k) The Radiators can be tube type or fin type or pressed steel type to achieve the desired cooling to limit the specified temperature rise. l) Transformer to be painted with poly urethane / powder coated ( colour light gray / smoke grey ) paints over anti-corrosive primer & shall be free from runs, sags, wrinkles, patchiness, brush makrs or other defects. All primers shall be well marked into the surface, particularly in areas where painting is evident and the first priming coat shall be applied as soon as possible after cleaning. (m) One No. 100mm dia dial type thermometer vapor pressure type having range 0 - 120 degree centigrade with temperature reading pointer, max temperature indicator and re-settling device. (n) Rating plate with terminal markings. (o) Two earthing terminals on tank / tank cover to facilitate fixing of 32 x 6mm GI earthing strip. (p) Lifting lugs