SPECIAL REPAIR / REPLACEMENT TO BER TRANSFORMER UNDER GE GANGTOK

Taking down of transformer of capacity from 63 KVA upto 200 KVA, from old cantt / new cantt Area under the AOR of GE Gangtok along with necessary T&P and Man power for depositing to MES store yard / MES Power House as directed by Eng-In-Charge .

Supply & install ,testing and commissioning of transformer as per IS : 1180 part - I, EEL-2 step down, copper Cu 99.9% purity, electrolytic grade wound 11KV/433 Volts (at no load) AC 3 phase 50 Hz 100 KVA capacity, core type, oil immersed naturally air cooled, oil natural air natural (ON/AN) , with external cooling tubes, delta connected on primary side (HV) and star connected on secondary side (LV) in accordance with vector group DYn-11 with neutral brought out on secondry side (LV) and having taping at +5% to -10% in steps of 2.5% on HV side to be changed by means of hand operated off load tap changer gear. The maximum temperature rise should not exceed 50 degree celsius in oil and 55 degree celsius in HV/LV winding when measured by resistance method after continuous full load run on an ambient temp of 40 degree celsius transformer shall be of BOLTLESS core design.

Transformer shall be double wound, core type with low loss, non ageing, high permeability CRGO prime core grade M-OH / ZDKH /TCH grade, perfectly insulated and clamped to minimize noise and vibrations. The transformer shall be IS/IEC 60076 and as per IS-1180 part - I of 2014 marked. Flux Density at rated voltage and rated frequency should be 1.688 T the transformer shall be designed as per CBIP manual 317 for over-fluxing witstand capacity of 110% continuous, 125% for 1 minute and 140% for 5 seconds. and over loading capacity of transformer shall be as per 6600 , Noise level as per NEMA TR1, with class A insulation, Tank pressure, Vaccum witstand capability & minimum clearances as per CBIP manual, No Load Current within 1% to 2% of Full load current Tranformer losses shall not exceed the loses mentioned in Table 6 of IS: 1180 of 2014 Part - I with Energy Effeciency Level - 2 and shall comprise of the following accessories :-

One cable box on HT side (Primary side) consisting of three nos porcelain bushing with copper rods, complete with nuts and washer , with cable glands suitable for reception/taking out 3 core 120 Sqmm, HT 11000 volts grade, XLPE insulated and PVC sheathed, heavy duty , armoured cables including jointing materials complete.

One cable box on LT side(secondary side) consisting of four nos porcelain bushing with copper rods, complete with nuts and washers, with cable glands suitable for reception/taking out single core /3.5 core of rated size/ runs of secondary currents, LT 1100 volts grade, PVC/XLPE insulated and PVC sheathed, heavy duty, armoured cables including jointing materials complete. with Bi metallic flexible connectors and copper bus bars of rated capacity with insulators support to be provided

Conservator with filter type drain valve and oil level guage.

De-hydrating breather with first fill of dehydrating agent (Silica Gel).

Explosive vent, Thermometer pocket on tank cover, oil level guage, Oil drain filter valve, Jacking / Lifting lugs, Marshalling Box,IP 55, with oil filling hole with cap/plug with connection plate complete, Air release valve plug and four nos plain solid cast steel detachable rollers.

One no 100 mm dia, dial type thermometer, vapour pressure type, having range 0-120 degree celsius with metal guard having maximum perimeter temperature reading indicator with re-setting device.

Two earthing terminals on tank cover to facilitate fixing of 50x6mm galvanised iron earth strip for earthing of body.