1. Steam Turbine Governor
Regulate STEAM FLOW into TURBINE such that at the desired
SPEED the OUTPUT TORQUE of the Turbine is exactly equal
the LOAD Torque of the Generator
(If torque is not equal the result is a change in speed – Newton’s Law)
In the event of sudden LOAD TORQUE loss, Quickly reduce
STEAM FLOW to maintain desired SPEED below Emergency
trip Speed
(excessive TURBINE OUTPUT TORQUE results in rapid speed increase)
In the event of a complete failure of speed control, emergency
over speed governor shall limit speed less than 120%

2. Steam Turbine Controls
Provide a means to prewarm
Provide a means to accelerate to speed and synchronize
Provide a means to control flow for MW generation
Provide a means to protect the equipment from adverse operating
conditions
Provide a means to test components to ensure operability

3. Turbine Control Hydraulics
Hydraulic Power Unit
Provide high pressure fluid to control the turbine valves
FAS (power for actuator positioning)
ETS (logic for tripping)
Lube Oil System
Provide front standard trip logic
Servo Valves
Solenoid Valves
Actuators
Steam valves
Front standard

4. Servo Valve
Null

5. Servo Valve
Opening

6. Servo Valve
Closing

7. Servo Valve
Failed Jet

8. Spring Can & Control Pac

10. Single Acting Servo Controlled
FAS supplied and ETS tripped
FASV de energized
Disk Dump spring seated
Shut off isolated
Biased Servo
Valve TRIPPED

11. Single Acting Servo Controlled
FAS supplied and ETS reset
FASV de energized
Disk Dump seated
Shut off reset
Null Servo

12. Single Acting Servo Controlled
FAS supplied and ETS reset
FASV de energized
Disk Dump seated
Shut off reset
Positive Servo
Valve Opening

13. Single Acting Servo Controlled
FAS supplied and ETS reset
FASV de energized
Disk Dump seated
Shut off reset
Null Servo
Valve position

14. Single Acting Servo Controlled
FAS supplied and ETS reset
FASV de energized
Disk Dump seated
Shut off reset
Negative Servo
Valve Closing

15. Single Acting Servo Controlled
FAS supplied and ETS reset
FASV energized
Disk Dump dumped
Shut off isolated
Biased Servo
Valve FAST CLOSED

16. Single Acting Solenoid Controlled
FAS supplied and ETS reset
FASV de energized
Disk Dump seated
Shut off reset
De Energized Solenoid
Valve Opening
Orifice controls rate

17. Single Acting Solenoid Controlled
FAS supplied and ETS reset
FASV de energized
Disk Dump seated
Shut off reset
Energized Solenoid
Valve Closing
Orifice controls rate

18. BLOCK

19. Main Stop ValvesMain Stop Valves
Primary Purpose: To shut off
steam flow in an emergency.
Secondary Purpose:
• Steam Chest Warming
• Rotor Warming

20. MSV

21. Main Control ValvesMain Control Valves
Purpose: To regulate steam flow to the HP
turbine.
• Control turbine speed (Speed Governor) or,
• Control generator load (Load Control) or,
• Control Reactor pressure (Pressure Governor)
1st
axiom of Turbine Controls-
One valve can control only one variable at one time

22. CV

23. CV Balance Chamber

24. MSV & CV

25. Reheat (Intermediate) Stop ValvesReheat (Intermediate) Stop Valves
Purpose: To shut off steam flow to IP (LP)
turbine in an emergency.

26. ISV

27. Intercept ValvesIntercept Valves
Primary Purpose: To regulate steam flow to the
IP (LP) turbine in an overspeed where the control
valves have been closed and speed continues to
increase. Also, to blow down reheater and/or
steam piping prior to opening of control valves.

28. IV

29. CIV

30. ByPass Valves
Purpose: Regulate reactor steam flow to the condenser,
when steam flow is not needed by the turbine
BPV use a simple double acting actuator (no ETS supply)
1) can be manualy opened during intial criticallity
2) regulated by Pressure Control over range of 150
to 1050 psig

31. ByPass Valves

33. Speed Control
Measure turbine speed and provide Speed error to Load Control
INPUTS
Turbine speed
Speed hold selection
Acceleration selection
OUTPUT
Speed Error to Load Control
Speed related Logic

34. First Line of Over Speed Protection
Control speed below over speed trip setting

35. Load Control
Using operator desired set points and measured turbine
conditions, provided a valve demand signal to Flow Control
Inputs
Speed error
Load reference
Operating condition (i.e. warming, rolling, or online)
BWR- Pressure error
Output
EsubL’s

36. Flow Control
INPUTS
EL
Valve Position
OUTPUT
Servo Current
Each valve has its own Flow Control Loop
MSV#2 (master)
CV 1, 2, 3 & 4
IV 1, 2 (master)
BPV 1 - 10

37. Flow Control
Admission Modes

38. Flow Control
2 Admission Mode

39. Incremental Regulation

40. Protection (trips)
Vital
Loss of Life
Redundant tripping and testable
Important
Loss of Capital
2 out of 3 logic for increased availability
Operational
Increased maintenance
Pre alarm

41. Second Line of Over Speed Protection
If First fails
Limit Peak Speed Below 120%