| 1 | Supply, installation, testing and commissioning of transformer outdoor type step down transformer 11kV/0.433 kV AC 3 phase, 50 Hz, 500 kVA capacity, core type copper wound, on HV & LV coil immerse, naturally cooled, oil natural-air natural (ONAN) with external cooling tubes, delta connected on primary side (HV) and star connected on secondary side (LV) in accordance with vector group DYN-II with neutral brought out on secondary side (LV) and having 7 step tapping at +/2.5% of each step (+5% to 10%) on HV side to be charged by means of hand operated OFF load tap change gear, the maximum temperature rise should not exceeds 45 degree celsius in oil and 55 degrees celsius in HV/LV winding when measured by resistance method after continuous full load run on and ambient temp of 40 degree celsius the transformer shall be in accordance with IS-1180 (Part-I) (level-3) with amendment No. 4, losses at 50 % Load -1354W, Losses at 100% Load - 3909W, Transformer must be BIS approved & BEE Marked, Manufacturer must have a NABL approved Lab and comprises of the following:-(a) Three porcelain bushing suitable for 11kV on HV side and including end termination box complete with copper rods, nuts, bolts and washers. (b) One cable end termination box on LT side (secondary side) consisting of four nos porcelain bushing with copper rods complete with nuts, bolts and washers. (c) Oil conservator with filter type drain valve and oil level guage. (d) De-hydration breather with filter fill of dehydrating agent (Silica gel). (e) Explosive vent, thermometer pocket on tank cover, oil drain filter valve, lifting lugs/ hooks, oil filter hole with cap/ plug with connection plate complete, air release valve plug and four nos plain cast steel detachable roller. (f) One No 100mm, 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. (g) Two earthing terminal on tank cover to facilitate fixing of 50 x 6mm galvanised iron earth strip for earthing of body. (h) Rating plate an terminal marking plate - 02 Nos. (j) Extra bushing for neutral in the LT cable box for providing independent set of earthing for neutral. (k) First filling of new and unused transformer oil IS 335 marked filtered and tested for dielectric strength not less than 50KV at 2.5mm air gap between testing electrodes. (l) Cable terminal Boot for transformer comprising of Basic Impulse level-95kV, Bushing diameter- 30-45mm, Voltage Um-17.5kV max, Description - Flexible Bushing Boots, Diameter D over Termination- 35mm-400mm, suitable for HT/LT XLPE UG Cable sizes- 95 to 240 sqmm.Note 1:- Certification of dielectric strength shall be submitted to the contractor after filling the oil.Note 2:- The Contractor is required to afford all facilities for factory visit, inspection of transformer, testing ON load and OFF load and examination of all material used & workmanship in items assembled or manufactured by them.Note 3:- (i) All the tests including pre-commissioning at site are to be conducted in presence of MES representative/ SEI and all test certificate duly signed by all concerned to be submitted by the contractor to the department before completion of work.(ii) The equipment should carry a guarantee of 30 months from the date of dispatch or 24 months from the date of completion of the contract, whichever is later. Any defect during this period will be attended in a period of three days including spares and labour without any extra cost to Govt. |
