Bids Are Invited For Custom Bid For Services - Annual maintenance of Generator & Turbine Equipment of 66 MW Hydro Generating Machines (Six Units) of Pong Power House, Talwara during the year 2024-25, Lump sum charges for Annual Mtc. of Generator & Turbine Equipment of 66 MW Hydro Generating Machines as per scope of work & other details, SCOPE OF WORK 1.0 ANNUAL MTC. OF PONG UNITS The maximum work completion period for each unit shall be 15 days . 1.1 TURBINE RUNNER AND DRAFT TUBE 1. Dye test of the Runner Blades to detect cracks in the blades. 2. Weld repair of runner blades which have developed crack . 3. Inspection of runner blades against cavitation along the profile of the various blades. Weld repair of the surface affected by cavitation and recording of observations. 4. Inspection of D.T. Cone/Cross-piece against cavitation weld repair and recording of observation. 5. Inspection of runner cone. Replacement of missing bolt if any. 6. Measurement and recording of G.V. Top & Bottom and bedding clearances as well as runner top & bottom labyrinth clearances, 7. Checking of D.T. Cone liner against any loosening of bondage with the concrete behind it. Filling of epoxy compound if required. 8. Painting of D.T. Cone liner, cone and X-piece with anticorrosive coal tar based epoxy paint . II. TURBINE PIT SHAFT GLAND SYSTEM, TURBINE GUIDE BEARING. 1. Cleaning of Turbine pit by washing with a water jet. 2. Checking of G.V. Servo-motors, damping pipes against leakage of oil and replacement of chevron packing, if required. 3. Inspection of studs and nuts of the top cover by tightening. 4. Painting of top over packets, breaking links, regulating ring, servo-motors and its allied piping system G.V. leavers and pit liner. 5. Dismantling the shaft gland system and checking the carbon sealing rings. 6. Adjustment of carbon sealing ring pieces for proper gaps and matching. 7. Checking / cleaning of compression springs, garter springs against rust and tension. 8. Checking of isolating seals. 9. Checking of gland cooling water system. 10. Painting of various components of shaft gland system. 11. Dismantling and inspection of guide bearing pads, polishing of pad surface, if required. 12. Checking of C seal cooling water pipe joints and coupling of replacement of their gaskets. 13. Cleaning of rotating sump and replacement of oil and circulation of oil through the centrifugal pump. 14. Cleaning of flow relay of the turbine guide bearing cooling water system. 15. Calibration of oil and pad thermometers, recording of error if any. 16. Checking / recording of Alarm Trip settings of T.G.B. pad temperature and alarm setting of oil sump temperature. 17. Checking of oil level float indication of T.G.B. 18. Recording of turbine guide bearing pad clearances. 19. Painting of various components of turbine guide bearing. III. BUTTER FLY VALVE AND ITS SERVO-MOTOR, PRESSURE RELIEF VALVE AND SPIRAL CASING. 1. Checking of the nuts & bolts and seal of the B.F. valve door. 2. Checking of B.F. Valve Servo -motor and allied piping against leakage of oil. 3. Cleaning of Rexorath valve oil filter. 4. Providing gland packing in the valves in the oil circuit of the B.F.valve serve-motor. 5. Checking of manual operation of the B.F. valve from the push buttons of the Solenoid valve on rexorath valve. 6. Painting of servo-motor and allied piping. 7. Cleaning & painting of B.F. valve outer body, pen-stock portion from B.F. valve to spiral casing. 8. Checking of P.R.V. seal, replacement if required. 9. Checking of sleeve and guides over the guides of P R ,Polishing of guides for smooth movement of sleeve ..V. 10. Checking of grease lines to P.R.V. linkage system in the pit and replacement of any damaged line. 11. Inspection of P.R.V. discharge hood against any cavitation, weld repair to arrest further cavitation. 12. Painting of P.R.V. body and other submerged components with anticorrosive coal tar based epoxy paint. 13. Cleaning of PAN. Servo-motor shaft to the linkage system. IV. PRESSURE PUMPIMG SET & GOVERNOR. 1. Checking of all hand valves in hydraulic system against leakage and providing gland packings. 2. Taking out the oil from P, P, set to the tanks for filtration and dehydration. 3. Cleaning of P.P. set oil tank and its painting if requited. Checking /Adjustment if required/recording of settings of idler valves, pressure switches and safety valve. 5. Dismantling of Governor oil pump motors, cleaning of stator windings, varnishing and drying and recording of I.R.values of all stator windings. 6. Greasing of Governor oil pumps-motor bearings. 7, Checking of coupling bolts of Governor oil pump motor unit. 8. Cleaning of Governor filter. 9 Checking and cleaning of Speed sensing disc and hydraulic over speed device. 10. Checking of Governor air valve, dismantling if required, filling of dash pot oil. 11. Checking of linkages for R.M.G. Mechanism. 12. Dry stroking after priming of the Governor. 13. Painting of Governor system. V. COOLING WATER SYSTEM,-C.G.L. SYSTEM & SYNCHRONOUS CONDENSER SYSTEM, 1. Checking and filling of gland packing in all valves in the cooling water system. 2. Checking of operation of cooling water electrically operated valve checking of operation of its limit switches. 3. Thoroughly cleaning of duplex strainer filters and the duplex strainer body. 4. Checking of valve and seat of the pressure relief valve provided in the cooling water circuit and its adjustment. 5. Checking of valves for cooling of runner labyrinths when machine is running on Synchronous mode of operation. 6. Checking of non-return/gate valve on the outlet of the cooling water system. 7. Painting of all the grease pumps of C.G.L. system. 8. Cleaning of the grease pumps of C.G.L. system, 9. Thorough checking of operation of both the lines physically the greasing of each and every point. 10. Checking of operation of pressure relay of C.G.L. system. 11. Checking of operation of feed dosers. 12. Painting of C.G.L. system. 13. Checking of electrodes provided for Synchronous condenser mode of operation for proper insulation. 14. Checking of oil operated servo valve for admission of air to D.T. Cone for Synchronous mode of operation. 15. Checking of Solenoid operated valve, non-return valve and manual valves in the air circuit of Synchronous mode of operation. 16. Checking & repairing of 300mm Oa c/w actuator valve as well as manual valve. 17. Checking and repair float of kinetic air valve meant for air release of spiral casing, 18. Checking and repairing of draft tube filling valves, 1I2 GENERATOR : STATOR WINDING Record stator windings IR Values at 2,5 KV before starting the Mtc. work (Phase to E: 15 sec, 1 min, 10 min; phase to phase = 15 sec, 1. min.) 2,121 2. Remove top & bottom overhang winding cover plates. Clean the windings as under:- a) Clean the loose foreign particles with a blast of hot air. b) Spray CRC-2-26 liquid on stator windings. Then clean it firstly with CRC/Turpentine oil soaked cloth and finally with fine dry cloth. c) Ensure that carbon deposited on the straight portion of coil sides coming out of stator core is thoroughly removed, as puncturing of coils normally takes place at this point. 3. Clean the stator core, slot wedges and ventilation ducts with air blast cum CRC-2-26 liquid. 4. Apply Dr, Becks red varnish on overhang windings once In 2 years. However, the same can be applied earlier if layer of varnish has peeled off. 5, Check all the top & bottom slot wedges, MAS blocks, glass tying cord for tightness & taper cut on the slot wedges should be in line with ventilating ducts. 6. Check stampings from frame end. If found rusty, remove rust and apply grey varnish. Paint the stator frame and core bolts with enamel paint. 7. Check all the joints of stator external terminals (mains and neutral for any over heating, In case of any doubt /looseness in tape, remove the tape & repair the Joint. Check tightness of stator core bolts. These should be tightened up to specified torque. Record movement of the bolts found loose. 9, Check all the R,T,Ds of stator winding, core and tooth and record their temperature and terminals at logo meter on T.G. panel. 10. Check stator space heaters for their healthiness. 11. Record the air gap between main stator and rotor. 12. Record IR values with motor operated Megger at 2.5 KV before clearing the machine for synchronization i.e. after boxing its P.I, should be more than 2. STATOR AIR COOLERS 1. Disconnect all the air coolers from the CAW pipe line. Remove end flanges and:- a) Clean all the cooling water tubes firstly with air blast, then with boiler brush and finally with cloth by pull through method. b) Clean the tub fins of carbon /dust. 2. Disconnect all the 12 Nos. 100mm N/B C/W valves from the circuit, remove its bonnet cover and check their moving cylindrical discs and spindles. Carryout necessary welding/repairs where required. Also clean 100 N/B pipes/elbows from inside. 3. Apply coal -tar epoxy paint on the inside of end flanges and enamel paint on outer surface of coolers, valves and pipings. 4. Check all the cold/hot air R.T,Ds & calibrate cold/hot air thermometers as well as C/W discharge thermometers. 5. Check the settings of 2 No. NO Contact hot air thermostats. It should close at 75°C. 6. Check the settings of 1 No. NC Contact heaters thermostats. It should switch on the heaters when hot air temperature falls below at 450C. 7. Check the lagging of 150 N/B cooling water heaters and repair it where ever deterioration is observed. 8. Set the alarms of cold/hot air dial thermometers as under: Hot Air : 70°C Cold Air : 45°C III. EXCITATION SYSTEM 1, Record IR values before starting the Mtc. jobs of the following at 1 KV with motor operated megger for 1 min,. i) Rotor pole field coils (from slip ring by removing brushes) to earth. 11) +ye Commutator Rockers to E iii) -ve Commutator Rockers to E iv) +ve Cable (to FB) to E v) +ve cable (return from F,B.) to E vi) Exciter armature to E viii) Magnetic frame to E (Exciter field poles) to E 2. Record air gap between:- i) Magnetic frame to excel er m armature it should be 6.35 mm (Avg.) and 12mm to 12.5 mm iaetrically. 3. i) Thoroughly clean exciter, flexible leads, compensating winding, rotor field leads, commutator and slip rings rockers /brush holders. ii) Clean rotor poles, insulation flanges and soldered series connections along with pole keys pockets. 4 Check all the Nuts & Bolts & fixing clamps for their tightness.#2y2.5 field bus and replace the blocks/Insulatiop Check all the condition of Insulation taps as insuuliaretdion blocks of rotor poles 5. 6. Check proper air gap of exciter air guide andpadjwuset rief rreequ 7. Check under cut of Mica of commutator se ments & ad ucistirwehde. re required. 8. to 1.5 Kg/cm2. Check the tension of commutator/slip ring brusjhes. It should be free from 1.4 9. Check the length of carbon brushes and replace those ones whose length is 114th of the original length. Also replace defective brush holders. 10. Measure the final IR values of the system after mtc. as per Sr. No. I. iv. GENERATOR THRUST & GUIDE BEARING 1. Drain out whole of the bearing oil Into the lubrication oil tank In the oil room. 2. Dismantle the oil vapour seal, vapour seal support ring and allied pipings, 3. Take out all guide pads one by one and Inspect them for any burs/high points on the white metal. Also check overall condition of the white metal, The burs/high points on the pad white metal surface should be thoroughly removed by polishing with fine oil stone. Center the machine vv.r.t. Turbine G.B. and runner labyrinths. Adjust the gap between guide pads and thrust collar to 0.20mm radially by adding /removing packers on the back of guide pads. 4. Check and calibrate the thrust bearing, guide bearing and bearing, oil dial thermometer & check their alarm contacts. Their setting be kept at 70°C, 55°C 45°C respectively. 5. Check the thrust and guide bearing alarm/tripping thermostats. Set them as under:- Thrust bearing alarm: 70°C, Guide bearing Alarm: 55°C Thrust bearing trippings: 75°C, G.B. Tripping: 65°C Also check all the bearing R.T.Ds. 6. Flush all the guide pads with clean turbine oil and re-assemble the dismantled assembles as above. 7, Record the gap between vapour seal and thrust collar, it should be from 0.25 mm to 0.40 mm respectively. 8. Open thrust bearing housing inspection windows. Jack up the rotor. Remove all the thrust pads one by one. Inspect them thoroughly. If any scratch /burr/high spot is noticed the same should be polished with fine oil stone. Also check the mirror face of thrust collar. 9. Clean all the springs by dipping the in petrol. Clean bearing housing and re- assemble it. 10. Check both lubrication oil P-M Units for their impellers, mechanical seal, motor fans, m couplings, foundations bolts, alignment etc. Check the flow relays. Check oil coolers and their allied pipings, valves and pressure gauges. Remove air of both coolers. n 11. Fill up the filtered oil in the bearing housing up to the required level and remove trapped air in the pipes of level gauge. 12. Centrifuge the bearing oil for about 24 hours and the oil temperature should be kept about 65°C during centrifuging. V. GENERATOR BRAKE SYSTEM 1. Thoroughly clean whole of braking system. 2. Check and record the thickness of brake pads. Replace complete set of their thickness is 1/4th of the original one. 3. Record the braking time. It should be less than 3 minutes. 4. Check the tightness of brake liner hold down bolts and their locking. Also check for 5. any but on the liner surface & polish if required. Check smooth operation of all the jacks. Dismantle & repair the defectiveO ON/ onFFeindication 6. Clean the limit switches & their contacts and ensure proper brakes on T.G. panel. Replace wiring where insulation has peeled off. 7 Check all the fittings In braking /jacking cabinet i.e, solenoid valve, puppet valves, 8. gate valves, non-return valves and pressure switch for proper operation. 9, Check tightness of eremite couplings, elbows of the pipes of braking system. I0. Ensure the brake pressure as 4.5 Kg/ cml, Adjust if required. Check the jacking pump periodically,for proper operation, VI. ROTOR Clean thoroughly all the rotor poles, their coils, ii-71--stu tion flanges, `. lJ F4,1 soldered joints and allied leads. Apply Dr. Becks red/grey varnish on all field coils after cleanin. top bottom Check and clean the following: g i) Remove top spider cover plates, clean spider housing. Check balancing weights and refix the copper plates. Ensure proper tightening /healthiness of lock nuts of these plates. Pole to pole connections and their Insulation sleeves. iii) Tightness of pole keys and spider rim keys with proper locking. iv) Locking of spider arm coupling bolts and rotor rim studs. Their welding tacks should be Intact, v) Rotor fans fixing bolts, vi) Rotor field +ve & -ve lead fixing clamps and insulation blocks. vii) Exciter air guide and air trunk fixing bolts. Apply 230 V AC with current less than 10 amps. to poles from sliprings with car to brushes removed and measure the voltage drop across each rotor field coil o ascertain the healthiness of inte-r-turn insulation. In case voltage drop across o s any i pole is low, check the voltage drop across each turn and repair the insulation of shorted turns. Measure the I.R. values of rotor field coils at 1 KV. 1.3 MISCELLANEOUS : 1. Painting of all machine components including auxiliaries as per applicable colour coding after preparation of surface. 2. Carry out the various tests of the machine. 3. Carry out the over speed test of machine. 4. After complete boxing of the unit, the site incharge of contractor will hand over the unit to officer in charge of BBMB according clearances in writing for filling water conducting system so as to enable rolling the unit on mechanical run. All the final parameters and gaps required shall be taken by the contractor as per the direction of site engineers & handed over to contractor before rolling of the unit. The site incharge of contractor shall depute his persons at all critical locations for monitoring parameters during mech. run and make a record of them. 5. During the mech. run, if any fault /leakage/abnormal operation of the unit occurs, the same shall be rectified by the contractor and the unit shall be rolled over again till the complete clearances. 6. After successful mech. run, unit shall be synchronized after completing all electrical tests, which shall be in BBMB scope but carried out in the presence of site incharge of contractor. 7. The contractor shall hand over the machine back to BBMB on successful & smooth operation of unit on load as per system constraints prevalent at that time. 8. Any other work which is not specified / covered in the above scope of work and which is required for successful completion of annual mtc, work shall be carried out by the contractor. 9. The maximum work completion periodfor ach unit shall be 15 das. Next Unit work shall be undertaken after completion of worek of first /previous unity and as on date as desired by BBMB and BBMB may ask for parallel work in two units for which nothing extra is payable. Note 1 The above list of maintenance activities may not be constructed a sequence of events as well as conclusive. 2 In case of any doubt in technical scope of work or technical particulars of Machines, the same may be clarified from the Engineer in charge during the site visit or through phone. Total Quantity :
