81492 REPAIRS AND MAINTENANCE OF HT EXTERNAL SERVICES AND ITS CONNECTED WORKS AT 7N DET UNDER GE TIRUNELVELI

De-hydration/ filtration of transformer oil by employing online filtration plant to achieve di-electric strength not less than 50 KV including the following services :- (a) Removal of all suspended particles such as dust, rust, scales, collided carbon, oxidation sludge, etc. upto < 1 micron. (b) De-hydration of transformer oil under vacuum. (c) Circulation of heated oil and filling of treated oil in transformer tank. (d) Top up with transformer oil upto required level NOTE : (i) Contractor shall use the vehicle mounted filtration plant with suitable size heavy duty hose pipe. (ii) The transformer oil required for replacing/top up shall be measured and paid separately (iii) Testing and issuing test reports for di-electric strength (before and after filtration) and acidity of transformer oil

Supply only transformer oil for top up in transformer complete all as specified and directed. Note : Transformer oil shall be bought in sealed container with minimum BDV 60 KV

Disconnecting HT/LT connection of transformer, 11000/433 V, 3 Phase, 4 wire system and opening up the top cover of transformer of capacity 100 KVA for checking the conditions and carryout repairs at site, including draining out oil from the transformer in suitable container (containers to be provided by the contractor) and repairs with replacement of parts (as required), checking the lead connection from winding to bus rods including necessary soldering/jointing and refilling with dehydrated oil after complete repair , replacing perished gasket with new one of same size and testing on full load after giving HT/LT connections complete all as specified and directed by Engineer-in- charge Notes : (i) Major parts as under shall be measured and paid separately under appropriate item of this BOQ (iii) Dehydration/ filtration of transformer oil shall be measured and paid separately under relevant item of this BOQ’ (iv) T&P and minor parts shall be arranged by the contractor and the cost thereof shall be deemed to be included in the unit rate quoted against this item (v) Rate deemed to be inclusive of securing the cables on HT/ LT side for tension free at cable entry box.

Material and Labour for replacement of HT bushing of transformer 11/0.433 KV of capacity 100 KVA complete all as specified and directed

Material and Labour for replacement of LT bushing of transformer 11/0.433 KV of capacity 100 KVA complete all as specified and directed.

Material and labour for replacement of silica gel breather of 11000/433 V transformer of capacity 100 KVA complete all as specified and directed.

Material and Labour for replacement of silica gel standard type complete all as specified and directed.

Supply and fixing in replacement Gun metal gate valve of 25 mm dia, ISI Marked suitable for oil inlet/outlet valves of transformer including taking down old existing complete all as specified and directed.

Servicing/calibration of HT 11 KV VCB along with CTs/PTs of current rating upto 400 A, rupturing capacity 250/200 MVA of any make and type by drawing out breaker assembly from panel and carry out the following works:- 1. Overhauling of all moving parts,2. Tripping latch and closing latch seating on tripping and closing shaft 3.Checking Vacuum interrupter Travel 4. Checking Vacuum interrupter Wipe out area. 5. Checking tripping coil, closing coil, Spring charging motor functional 6. Check VCB rack in/out functional. 7.Checking VCB Mechanical interlock function will be checked in both TESTS, SERVICE position 8. Checking VCB electrical wiring 10. VCB ON/OFF functional checks by both Manually/Electrically 11. checking Contact spring compression load ,12. Insulation testing shall be checked for VCB 12. Calibration of Protective relays over current and earth fault relay, under voltage relay, over voltage relay, Auxiliary relay, master trip relay or any other type by using relay injection kit including necessary adjustment of over current / earth fault / earth leakage by secondary current injection test along with testing and calibration of pickup current, time setting multiplier, tripping delay time, auto resetting of time, etc. for successful operation at the time of fault occurrence as required according to the connected load NOTE : (i) The cost of arranging HT Insulation tester, cleaning materials, HT Tape, thinner, cotton waste, steel nut, bolt with double washers, HRC fuses, , fuse carrier base, shall deemed to be included in the quoted rate. (ii) Contractor shall isolate and earth the breaker before starting the work.

Supply and fixing in replacement LED indicator of RED/GREEN/YELLOW/AMBER complete all as specified and directed.