SPECIAL REPAIR/REPLACEMENT OF TRANSFORMER AGAINST BER FOR MRS UNDER GE PANAGARH

Amount

Supply and install, testing and commissioning of step down outdoor type copper would Power transformer of capacity 3150 KVA complete (Plateform mounted) with standard, fitting HT 33000 V, 3 Phase, LT 11000 volts, 3 phase (33/11 KV Delta/Star, Vector Group DYn11) with off load change over switch on HT side to vary secondary voltage with range +7.5% to -7.5% with steps @ 2.5% all as per IS 2026 ,complete all as specified and as directed by Engrs-in-Charge. (i) No load Voltage Ratio (Normal Tap) - 33000/11000 V (ii) Number of phases : Three (iii) Frequency : 50 (iv) Type of Cooling : ONAN (v) Winding connections : The primary winding (HV) shall be connected in delta and secondary winding ( LV) shall be connected in star. (vi) Vector Group : Windings shall be connected as per Vector symbol : DYn11 (vii) Neutral Earthing : The neutral point of Secondary (LV) winding shall be brought out to a separate insulated terminal and shall be solidly earthed. (viii) Off Load Tap Changer of the transformer : Voltage tapping range on H.V. side will be (+7.5%) to (-7.5%) insteps of 2.5%. The tap changing switch shall be located in a convenient position so that it can be operated from ground level. The switch handle shall be provided with a locking arrangement along with tap position, enabling the switch to be locked in position. The tap position marking should increase in clockwise direction and there should be a back stopper in between tap position 1(+7.5%) & 7(-7.5%). (ix) The percentage impedance at 75 °C & 50 Hz refer to the (normal) principal Tapping shall be 6.25. (x) Losses : Standard losses will be as follows : (a) No load loss at 33/11 KV voltage ratio and 50 Hz frequency - 3.5 KW (Max) (b) Full load loss at 33/11 KV voltage ratio and 75 °C - 28 KW (Max)

Item No 1 Contd…. (xi) Terminals : (a) H.V.Bushing (33 KV Side) - 36KV Class Porcelain bushing with plain sheds for heavily polluted atmosphere (b) L.V.Bushing (11KV Side) - 12 KV Class Porcelain bushing with plain sheds for heavily polluted atmosphere. (c) Neutral Bushing - Neutral of L.V. winding shall be brought out through porcelain bushing similar to L.V. Bushing for connection with earth terminal in line with LV bushing. (xii) The following fittings and accessories shall be supplied with each Transformer : 1. Outdoor type bushing – HV - 3 Nos. and LV - 4 Nos. 2. Conservator with atmoseal and supporting bracket or structure as the case may be. 3. Isolating valve for conservator in between conservator and Buchholtz Relay and in between Buchholtz relay and main tank.. 4. Conservator valves for driven out air between air cell & wall of conservator & connection to breather. 5. Conservator drain valve. 6. Dial type oil level indicator complete with alarm contact. 7. Silica gel breather with oil seal and connecting pipe. The breather shall be accessible for inspection from ground. 8. Spring loaded setting type pressure relief Valve having suitable opening Port. Hole & provision of visual indication for opening of the valve & Alarm/Trip contact arrangement. 9. Access/inspection holes with bolted cover for access to inner ends of bushing. 10. Cover lifting eyes. 11. Lifting eyes for core frame with windings. 12. Tap changing arrangement with hand wheel for Off-Load tap-switch 13. Air release plug on top of cover or explosion vent will be provided. 14. Upper filter valve and bottom filter valve. 15. Drain valve.

Item No 1 Contd…. 16. Top and bottom oil sampling devices. Provision for oil sample collection during process of filtration should be made. 17. Lifting lugs. 18. Jacking pads with handling holes at four corners. 19. Transport lugs. 20. Under carriage base channel. 21. Tank earthing terminals – 2 Nos. 22. Bachholtz relay double float type with one set of alarm contacts, one set of trip contacts and testing pet cock. The contacts should be wired with a PVC armoured cable. 23. Dial thermometer for winding temperature with alarm contacts and Trip contacts. 24. Dial thermometer for oil temperature with alarm contacts and Trip Contacts. 25. An additional pocket for inserting thermometer for oil temperature indication. 26. Weather proof control cabinet for marshalling terminal connections from protective and indicative devices. The cabinet shall be provided with incandescent filament lighting, plugs etc. 27. Neutral Bushing 28. Rating plate, as per I.S.S. 29. Diagram Plate . Make: Schneider/ Seimens /BHEL

M/S ANANDA ENTERPRISE

MBS TRADING CO.