An overview of start up means for Gas turbine and real-time simulator HMI screens indicating the full start-up of Gas turbine till it reaches full speed no load (FSNL), Start-up curve, Relays that get activated at the corresponding speed and Emergency stop system.

1. STARTUP OF A GAS TURBINE
2×GE FRAME 9FA GAS TURBINE
750MW COMBINED CYCLE
POWER PLANT

2. Why a starting mean is required to start a gas
turbine?
• Like other internal combustion engines, a gas turbine cannot
produce torque at zero speed.
• The starting mean system is used to start the gas turbine
rolling, crank it to firing speed and assist the fired turbine to
self-sustaining speed.
• This is accomplished by a motor, generator or other starting
device operating through a torque converter coupled to the
accessory gear.
• This arrangement provides the cranking torque for turbine
start-up and during shutdown this continues to rotate the
turbine rotor at slow speed for cool down purposes.

3. Depending on the plant and the type of Gas turbine
starting means are classified as follows:
Gas
turbine
Generator
Diesel
engine
Motor

4. Generator

5. Diesel engine

6. Why starting mean require Torque converter
• Acceleration to purge speed.
• Acceleration to firing speed.
• Assisting the gas turbine till it reaches self sustained
speed.

7. Motor with torque converter
Hydraulic Oil Pump
Accessory
Drive Gear
Torque
Converter

8. Why Turning gear mechanism is required?
• The turning gear provides the power necessary to breakaway
and rotate the turbine prior to turbine start and also to rotate
the shafting after turbine shutdown to avoid deformation of it
shafting's.

9. Turning gear mechanism

10. Why SSS Clutch is required in starting operation
of turbine?
• Its an over running clutch for automatic engagement
and disengagement.
• It is a self engaging in breakaway or turning mode
and over runs when turbine/generator shafting speed
exceeds turning gear drive packaged speed.

11. The most commonly used type of clutch is SSS
(Synchronous Self Shifting ) Clutch.
SSS clutch working

12. Electrical to mechanical power conversion
Exhaust
Rotating
shaft
Generator
Gas turbine
Grid
TransformerPumps
Starting
apparatus
• If a Generator is selected as a starting mean then it behaves
like a motor and draws current from the Grid to perform the
startup operation of a gas turbine .

13. Start up curve of gas turbine

14. Why post and pre lubrication is required during
startup and shutdown of gas turbine?
• Gas turbine lubrication is started before the actual
start up and after shutdown for a short period of time
to ensure effective lubrication of the gas turbine parts
and increase the performance of the gas turbine parts.

15. Accessory
Coupling
Active
Thrust
Inactive
Thrust
No # 1
Journal
Bearing
Load
Coupling
Load
Equipment
Coupling
Oil
Lube Oil
Drain to
Reservoir
Bearing
Oil
No # 2
Journal
Bearing

16. STARTUP STEPS
 Purging
 Warming up time
 Auxiliary lube/hydraulic oil pump and Ratchet motor
start, Jaw clutch will engage, Diesel engine start
START
(14HR(0% SPEED)
CRANKING
14HM(20% SPEED)
FIRE
(UPTO 50% SPEED)
 At 60% speed Diesel engine disengage and
shutdown
ACCELERATE
14HA(50% SPEED)
 At 95% speed aux lube/hydraulic oil pump stop,
bleed valves closes
FSNL
14HS(95% SPEED)

17. STARTUP SCREEN WITH MASTER CONTROL
START AND STOP OPTION

18. Why start check screen is required?
• In order to ensure the successful start up of a gas
turbine all the axillaries and other compartments are
to be checked.
• This is ensured with the help of a start check screen
which gives the status of the auxiliaries with a green
signal that indicate the proper state to start the gas
turbine.

19. Start check screen with READY TO START signal.

20. Instructor station with dialog box questioning whether to Start the Turbine

21. Start check screen with NOT READY TO START status

22. STARTUP SCREEN WITH READY TO START STATUS

23. What is Cranking? Why cranking is required?
• Its a process during which a gas turbine is made to run at a
required speed during start up and shutdown operation, in order
to prevent turbine rotor undergoing hogging and sagging.

24. STARTUP STATUS – CRANKING

25. Why purge timer is required?
• Depending on the type of fuel and based on the
type of start (fast start or normal start) purge time is
fixed
• Purging is required to flush out and choke out liquid
fuel nozzles which may have traces and residues
which are left out in the combustion chamber, after
the shutdown operation of gas turbine.
• Depending on the type of fuel used in combustion
chamber the purge timer is set.

26. Why Warming up of a gas turbine is required?
• In order to have low cycle fatigue on hot gas components.
they are internally heated and are exposed to a constant
temperature .
• Sudden heating and cooling of hot gas components is not
recommended, so warming up of hot gas components is
carried out

27. STARTUP STATUS – WARMING UP

28. What is Firing of a gas turbine?
• When admission of fuel in the combustion chamber takes place
firing occurs.
• During this period of time the gas turbine will have firing status.

29. STARTUP STATUS – FIRING

30. STARTUP STATUS – ACCELERATING

31. RUN STATUS – FSNL

32. RUN STATUS – COMPLETE SEQUENCE

33. RUN STATUS – LOADING
CLOSED

34. RUN STATUS – LOADING
CLOSED

35. RUN STATUS – BASE LOAD
CLOSED

36. Why Emergency stop system is required
• Whenever an abnormal functioning of gas turbine is
observed during the field stroking operation, then the
gas turbine can be immediately stopped using the
emergency stop system.

37. Emergency stop system

38. Thank you