8705REPAIR AND MAINTENANCE OF TRANSFORMERS, HT BREAKERS, HT CABLES, HT AND LT PANELS, MCCBs, EARTHING SYSTEMS AND ASSOCIATED ELECTRICAL INSTALLATIONS AT OUTLYING AREAS, INS SHIKRA, NT POOL AND BOAT POOL UNDER GE (NW) NOFRA.

Disconnecting, dismantling, repairing/overhauling, reassembling, testing and commissioning of existing indoor, 11 kV, horizontal draw-out type OCB trolley of rupturing capacity 250 MVA and current rating 400 Amps, complete, including removal from its installed position, carrying out complete servicing, refitting in the original position, testing and commissioning, all as specified and as directed by the Engineer-in-Charge. Note:Spare parts and new transformer oil shall be measured and paid for separately under relevant BOQ items.

The scope of work shall include the following: (i) Inspecting and overhauling the spring operating mechanism, including checking the mechanism, hold-on catch assembly, trip bridge, Z-screw, U-cam, aluminium trip bridge and main trip lever assembly, and applying suitable multi-purpose grease for smooth operation. (ii) Inspecting and overhauling the OLTLF assembly, earth-fault release assembly, tripping coil and auxiliary switch, including checking and rectification of the electrical wiring system. (iii) Inspecting, overhauling and cleaning insulators, moving contacts, fixed contacts and arcing chambers using suitable contact/carbon cleaning solution, and applying dry graphite conductive compound/sealant to contact surfaces to prevent carbon deposits and ensure proper electrical contact. (iv) Cleaning the OCB oil tank internally and externally using suitable cleaning agent, including removal of sludge/deposits, checking the tank and applying heavy-duty grease to the tank raising/lowering guide mechanism. Transformer/OCB oil, approximately 60 litres per OCB, shall be measured and paid for separately. (v) Reassembling all components in their respective positions and carrying out functional testing, high-voltage testing and insulation resistance (megger) testing before and after the high-voltage test, complete, all as specified and as directed by the Engineer-in-Charge.

(iv) Reassembly of all dismantled components, alignment and adjustment of the complete operating mechanism, checking of mechanical and electrical interlocks, functional operation of the breaker, insulation resistance (IR) test using 5 kV megger before and after servicing, High Voltage (HV) withstand test as per relevant IS/IEC standards, operational testing including closing and tripping operations, and commissioning complete, ensuring satisfactory performance in all respects.

Material & labour for Painting of HT OCB of capacity 250/350 MVA, 11 kV, 400 Amps, including cleaning, scraping and filling of cavities, application of one coat of red oxide primer followed by one coat of approved synthetic enamel paint on external and internal surfaces, complete, all as specified and as directed by the Engineer-in-Charge.

Material and labour for Disconnecting and dismantling of existing indoor-type, 11 kV, horizontal draw-out type VCB trolley of rupturing capacity 250/350 MVA and rating 400/630/800 Amps from its location and carrying out repair/overhauling, including inspection, cleaning, servicing, testing and reassembly of all components, complete, all as specified and as directed by the Engineer-in-Charge. Note: The cost of defective spare parts replaced during servicing/overhauling shall be measured and paid separately under the relevant BOQ items.

The scope of work shall include the following: (i) Inspecting and overhauling the manual/motorised spring charging mechanism, including checking the operating mechanism, motor and gear assembly, main gear assembly, stop-bolt assembly, main shaft interlocking assembly, closing spring assembly, small cam with screw, motor cut-off limit switch and butterfly switch assembly, and applying suitable multi-purpose grease for smooth operation. (ii) Inspecting and overhauling the OLTLF assembly, earth-fault release assembly, tripping coil and auxiliary switch, including checking and rectification of the electrical wiring system. (iii) Inspecting, overhauling and cleaning the through/spout insulators and vacuum interrupters using suitable contact/carbon cleaning solution, and applying dry graphite conductive compound/sealant to electrical contact surfaces to prevent carbon deposits and ensure proper electrical contact. (iv) Reassembling all components in their respective positions and carrying out functional testing, high-voltage (DC) testing and insulation resistance (megger) testing before and after the high-voltage test, complete, all as specified and as directed by the Engineer-in-Charge.

Material & Labour for Painting of HT VCB of capacity 250/350 MVA, 11 kV, 400/630/800 Amps, including cleaning, scraping and filling of cavities, application of one coat of red oxide primer followed by one coat of approved synthetic enamel paint on external and internal surfaces, complete, all as specified and as directed by the Engineer-in-Charge.

Material and labour for opening and carrying out inspection, cleaning, overhauling and servicing of busbar chamber, CT chamber, PT chamber and metering chamber of existing 11 kV HT panel board, including the following activities, complete, all as specified and as directed by the Engineer-in-Charge. Note: Spare parts shall be measured and paid for separately.

The scope of work shall include the following: (i) Inspecting, cleaning and overhauling of busbar chamber, including checking busbars, spout insulators and space heaters, removal of dust using vacuum cleaner/blower and moisture using hot-air blower, checking and tightening of busbar and insulator connections, application of suitable insulating materials/compounds such as STRIPPEX-A, STRIPPEX-B and HT tape, and carrying out high-voltage (DC) and insulation resistance (megger) tests before and after the high-voltage test, complete. (ii) Inspecting, cleaning and overhauling of CT/PT chamber, including checking busbars, spout insulators, space heaters and wiring system, removal of dust using vacuum cleaner/blower and moisture using hot-air blower, checking and tightening of connections, application of suitable anti-tracking paint on CTs and insulators and HT tape, complete. (iii) Inspecting, cleaning and overhauling of metering chamber, including checking the complete wiring system, meters, selector switches and control fuses, removal of dust using vacuum cleaner/blower and moisture using hot-air blower, and checking and tightening of wiring connections, complete.

Material & Labour for Overhauling and secondary injection testing of overcurrent and earth-fault relays/releases at each multiple setting using artificial load, including readjustment of settings and complete testing, all as specified and as directed by the Engineer-in-Charge.