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Turbine Rolling & Synchronisation

Turbine Rolling & Synchronisation. www.powerpointpresentationon.blogspot.com. OBJECTIVE. THE OBJECTIVE OF STARTING UP OF THE TURBOGENERATOR IS TO BRING A UNIT ON LOAD AND RAISE IT TO THE RATED OUTPUT WITHIN THE OPTIMUM TIME BUT WITHOUT UNDUE STRESSES ON THE TURBINE COMPONENTS.

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Turbine Rolling & Synchronisation

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  1. Turbine Rolling & Synchronisation www.powerpointpresentationon.blogspot.com

  2. OBJECTIVE • THE OBJECTIVE OF STARTING UP OF THE TURBOGENERATOR IS TO BRING A UNIT ON LOAD AND RAISE IT TO THE RATED OUTPUT WITHIN THE OPTIMUM TIME BUT WITHOUT UNDUE STRESSES ON THE TURBINE COMPONENTS.

  3. TYPES OF START UP • Turbine Start up are classified as Cold, Hot & Warm Start up • Cold Start up – If HPT metal Tempr<1500C. • Warm start up – If HPT metal tempr betwn 150 to 3500C. • Hot start up – If HPT metal temp > 3500C.

  4. General Preparation of Start up • All the repair works on the turbine are completed and all PTWs are cancelled. • All the Turbo-supervisory instruments are available. • Generator excitation system,GT & UAT cooling system,seal oil system etc.are OK • All the interlocks and protections of Turbine & Generator are already checked up and kept I/s.

  5. Unit status before Turbine Rolling • Turbo-Generator on Burring gear with all Turbo supervisory parameters are normal. • Boiler is lighted up condition with one or two oil elevations are I/s. • HP-LP Bypass is in charged condition. • Boiler load index is 95 to 100 T/Hr. • Steam parameter are ready for rolling. M.S. Pr. 35-40 Ksc. HRH Pr. 12-14 Ksc. M.S. and HRH Tempr. – 320 to 3500C

  6. Start up Considerations • During the startup the Turbine is subjected to “Non-Steady state operation”. • This covers the operating condn whereSpeed, steam Pressure and temperature change with time. • Under these condn turbine components which are exposed to temperature changes subjected to thermal stress and expansion. • For turbine life point of view, it is very much necessary to limit the extent of these temperature changes.

  7. To take care of the above factor the operator has to follow the recommendations from Turbine Stress Evaluator and start the Rolling procedure by following Criteria curves X1 to X7 right from the beginning. • TURBINE STRESS EVALUATOR The Turbine is equipped with the TSE which provides adequate guidance to the operator by indicating tempr margins and Load margins. These Margins have been derived on the basis of Actual Thermal Stress and Material Fatigue.

  8. Frequent and substantial departures from criteria curves and TSE Indication can result a.Reduction in total life of Turbine b.Non permissible deformation. and c.Cracking of Turbine Components.

  9. RESETTING THE TURBINE • Why Turbine Resetting? When the Turbine trips due to Electrical or Mechanical Protection Trip oil drains quickly. In the absence of the Trip oil Turbine Stop and Control vlvs closes quickly. So the Trip oil is basically required for keeping the ESVs and IVs in open condn and getting required Secondary oil pressr for opening the HPCVs and IPCVs. .

  10. The Trip oil again can be generated again by Resetting the Turbine. Now to Reset the Turbine We have to • Reset the Unit Or Master Trip Relay. • Bring the Starting Device to Zero.

  11. UNIT or MASTER TRIP RELAY can be reset • By Resetting Boiler Master Fuel Trip Relays. • All Generator Trip Relays Reset. and • Turbine Electrical Protections to be Reset.

  12. The Zero position of starting device generates a. Start up oil and b. Aux start up oil. • Aux start up oil is required to reset Trip gear. • Start up oil is required for opening ESVs and IVs. • It also ensures that the control vlvs opening are prevented till ESVs and IVs are opened.

  13. Unit status before Turbine Rolling • Turbo-Generator on Burring gear with all Turbo supervisory parameters are normal. • Boiler is lighted up condition with one or two oil elevations are I/s. • HP-LP Bypass is in charged condition. • Boiler load index is 95 to 100 T/Hr. • Steam parameter are ready for rolling. M.S. Pr. 35-40 Ksc. HRH Pr. 12-14 Ksc. M.S. and HRH Tempr. – 320 to 3500C

  14. Opening of ESVs and IVs • Before opening of Stop vlvs following drains to be kept opened. 1. MS Strainer drains 2. HRH Strainer drains 3. Seat drain before ESVs4. Seat drain before IVs. • TSE selected in Admission mode. • HP-IP Trim device on. • Following SLCs of the following equpts are ON a. Oil p/ps and Turning Gear. b.LP water injection d. HPCV Warm-up control vlvs. e. All drain vlvs. • The Criteria for MS and HRH Superheat and X1 and X3 are satisfied.

  15. STEAM WITH 50O SUPERHEAT

  16. RECOMMENDED MINIMUM CURVE (CURVE-A) AND MAXIMUM (CURVE-B) MAIN STEAM TEMPERATURE AHEAD OF TURBINE WHEN OPENING THE MAIN STOP VALVES.

  17. Starting Device to beraised to 42% OBSERVATIONS • ESV 1& 2 are open. • HPCV warm up drain vlvs starts opening. • HPCV Surface and Mid Metal Tempr start showing increasing trends and they should be given proper time to stabilize.

  18. RAISE STARTING DEVICE TO 56% OBSERVATION IV1 AND IV2 ARE FULL OPEN Bring the Turbine to soaking speed. Before rolling the turbine to soaking speed it is to be ensured 1. TSE to kept on Turbine mode. 2. Criteria curve x4 and x5 for opening the control valves must be satisfied.

  19. RECOMMENDED MINIMUM MAIN STEAM TEMPERATURE AHEAD OF TURBINE BEFORE OPENING THE MAIN CONTROL VALVES

  20. RECOMMENDED MINIMUM REHEAT TEMPERATURE AHEAD OF IP TURBINE BEFORE OPENING THE REHEAT CONTROL VALVES

  21. EHC should be ready for operation and Speed controller is active. • Tracking Device to be kept “ON”. (Starting device to be made 70% in case Tracking Device facility is not available). • Hydraulic Governor to be kept bypassed by raising the speeder gear to 100%.

  22. Speed Reference is raised to 600 rpm OBSERVATION • Gate valve Gearing closes at 240 rpm. • JOP trips at 540 rpm. • Turbine speed stabilizes at 600-650 rpm. • All Turbo supervisory parameters are normal.

  23. Speed raising to 3000rpm Speed is raised to 3000 rpm once the conditions are mentioned below are fulfilled • TSE is selected on Turbine mode. • TSE upper margin > 400k. • Criteria curve x6 is satisfied. which ensures the proper warming up of HP Turbine w.r.t. M.S.Temperature.

  24. The Differential Expansion are within limits. • The Top & Bottom temperature difference of casing are within limits (35 Deg). • Sufficient Steam generation in the Boiler to meet the requirement of the Turbine for Block Loading after Synchronisation.

  25. RECOMMENDED MAXIMUM MAIN STEAM TEMPERATURE AHEAD OF TURBINE BEFORE THE TURBINE IS BROUGHT TO RATED SPEED

  26. Speed reference raised to 3000rpm OBSERVATION • Vibration level to be watched at critical speed at 1500 rpm and 2400 r.p.m. • AOP can be taken out at 2850 r.p.m. • All TSI parameters should preferably within normal values. Turbine to be soaked at 3000 rpm to fulfill X7 criteria.

  27. RECOMMENDED MAXIMUM MAIN REHEAT TEMPERATURE BEFORE TURBINE IS LOADED

  28. Generator Synchronization and Block loading • Load Controller to be switched ON. • Load Reference to be set to 20 MW. • Load limit to be set at 50 MW. • Load Gradient to be switched ON. • Load Gradient to be set on 10 MW/Min.

  29. Limit Pressure Mode to be selected. • Generator Earthing Switch to be opened. • Bus side Isolator and Generator side Isolator to be closed. • Generator Protections to be kept on that breaker which is to be closed for joining with grid. • All the Turbo supervisory parameter are checked and ensured that they are normal.

  30. Synchronization Procedure • Generator Field Breaker closed. • Generator Terminal Voltage built up to 15.75KV by increasing excitation voltage. • Synchroscope switch kept on CHECK mode. • Voltage,Frequency of incoming power are matched with the same of running(Grid). • Generator breaker closed once “In Synchronism” lamp appears at 12O clock Synchroscope needle position. (Rotation of needle should be in clockwise direction).

  31. Load controller takes up load to 20 MW thus avoiding tripping of Generator on “Low Forward Power Protection”. • Starting device raised to 100%. • HP-LP Bypass closed. • All MS, HRH, CRH and Cylinder drains are closed after 5% loading has been done.

  32. Turbine Rolling with Hydraulic governor • Turbine has to be reset as usual before rolling. • Following things are to be taken care of before raising Starting device. • Tracking Device Off. • Speeder Gear Position zero. • Speed Reference position zero.

  33. Speed reference raised to 100%. EHC output goes to 100%. • Starting device position raised to 43%. ESVS get opened. • Starting device further raised to 56%. IVS get opened. • Henceforth starting device is raised carefully and speed is brought to 600 rpm by trial and error method.

  34. Turbine soaked at 600 rpm. • Before increasing speed to 3000 rpm a. TSE upper margin>400. b. X6criteria curve satisfied. • Starting device raised to 100% non stop. a.Turbine speed rises to 2700 rpm. • Hydraulic governor takes over at 90% of rated speed(2700 rpm). Hence further speed is raised by Speeder gear.

  35. Speeder gear position further raised and speed is stabilized at 3020 rpm. • Turbine soaked at same speed to fulfill X7criteria for further loading. • Synchronization and Block loading(by increasing speeder gear) done.

  36. Any Question ?

  37. THANK YOU

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