SPECIAL REPAIRS FOR STANDBY TROLLEY MOUNTED SPARE TRANSFORMERS GE (NORTH) SANTACRUZ AT MUMBAI

Supply and install testing and commissioning of outdoor trolley mounted type transformer stepdown 11000Volts/415 volts copper wound of capacity 315 KVA , efficiency Level-2 transformer as per IS-1180 with standared accessaries complete with cable termination box on both HT and LT side ,Initial filled transformer oil, Conservator, Breather with silica gel, Off load tap changer 7 position with variation of 2.5% ,Thermometer pockets with thermometer, Explosion Vent, Oil drain plug, Air vent plug etc and connecting up with existing cabls all as directed by Engr-in-charge. (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 atmospher if required. The complete design of core must ensure permanency of the core loss with continous working of the transformers. LV winding shall be such that neutral formation will be at top. Curent 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 lifiting 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 botom 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 vaccum of 0.7 kg / sqcm (g) without any deformation.

(e) Audible sound levels for 315 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 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 receiption 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 gray ) paints over anti-corrosive primer and 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, Amendement - 4 of March 2021.

Material and labour for factory made trolley for transformer of size 2.8 x 2.5 Mtr made out of mild steel angle/ channels medium weight beams and MS flates with necessary welding in any position drilling in hot/cold etc for longitude and cross members of trolly made out of ISMC channel 100 and top of the members coverd with 6 mm thick MS plate platform and vertical support over the platform with MS equal angle of size 50 x 50 x 6 mm thick angles with MS flate 50 x 5 mm thick for two runs of bracing the supports, V type towing frame with hook with spring and check nuts and mounting bracket with bush for movement of tow assembly. The assembly made out of ISMC channel 100 with long and cross member, turning plate assembly for front wheel only fitted in front axle, the front and rear axle made out of medium weight beam ISMB 100 including tyre with tube F78-15 8 play rataing four nos with wheel drum, mounting bracket, bearings, check nuts, locknuts, key etc welded with medium beam with nut bolts washers as required for mounting the transformer and other fixing arrangement for proper toeing with Eicher vehicle and supporting legs 04 nos with necessary screw jack system for static support on steady position complete all as directed.

Supply, laying and testing XLPE insulated screened PVC bedded, galvanized steel strip or wire armored, electric power cables (heavy duty) with stranded aluminum conductor, 11000 volts grade, of size 95 sqmm, 3 core incl taking down unsv one complete.

S&F Cable jointing kit for 11 KV (Earthed) grade cable for indoor termination heat shrink type joint complete with jointing material and accessories suitable for 3 core XLPE armoured aluminium conductor cable of size 95 sqmm complete.

S&F Cable jointing kit for 11 KV (Earthed) grade cable for outdoor termination heat shrink type joint complete with jointing material and accessories suitable for 3 core XLPE armoured aluminium conductor cable of size 95 sqmm complete.