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Turbinecontrolbasic
The document discusses steam turbine governor systems and controls. It describes how governors regulate steam flow to maintain desired turbine speed even as load torque changes. It also describes emergency controls to reduce steam flow if load is lost to prevent overspeed, or trip the turbine if speed cannot be controlled. The document then summarizes various turbine control components, including hydraulic and electronic controls, valves, actuators and their functions in speed control, load control, flow control and overspeed protection.
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Turbinecontrolbasic
- 1. Steam Turbine Governor RegulateSTEAM 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 Providea 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 HydraulicPower 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
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- 8. Spring Can &Control Pac
- 10. Single Acting ServoControlled FAS supplied and ETS tripped FASV de energized Disk Dump spring seated Shut off isolated Biased Servo Valve TRIPPED
- 11. Single Acting ServoControlled FAS supplied and ETS reset FASV de energized Disk Dump seated Shut off reset Null Servo
- 12. Single Acting ServoControlled FAS supplied and ETS reset FASV de energized Disk Dump seated Shut off reset Positive Servo Valve Opening
- 13. Single Acting ServoControlled FAS supplied and ETS reset FASV de energized Disk Dump seated Shut off reset Null Servo Valve position
- 14. Single Acting ServoControlled FAS supplied and ETS reset FASV de energized Disk Dump seated Shut off reset Negative Servo Valve Closing
- 15. Single Acting ServoControlled FAS supplied and ETS reset FASV energized Disk Dump dumped Shut off isolated Biased Servo Valve FAST CLOSED
- 16. Single Acting SolenoidControlled 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 SolenoidControlled FAS supplied and ETS reset FASV de energized Disk Dump seated Shut off reset Energized Solenoid Valve Closing Orifice controls rate
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- 19. Main Stop ValvesMainStop Valves Primary Purpose: To shut off steam flow in an emergency. Secondary Purpose: • Steam Chest Warming • Rotor Warming
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- 21. Main Control ValvesMainControl 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
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- 25. Reheat (Intermediate) StopValvesReheat (Intermediate) Stop Valves Purpose: To shut off steam flow to IP (LP) turbine in an emergency.
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- 27. Intercept ValvesIntercept Valves PrimaryPurpose: 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.
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- 30. ByPass Valves Purpose: Regulatereactor 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
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- 33. Speed Control Measure turbinespeed 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 ofOver Speed Protection Control speed below over speed trip setting
- 35. Load Control Using operatordesired 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 ServoCurrent Each valve has its own Flow Control Loop MSV#2 (master) CV 1, 2, 3 & 4 IV 1, 2 (master) BPV 1 - 10
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- 40. Protection (trips) Vital Loss ofLife Redundant tripping and testable Important Loss of Capital 2 out of 3 logic for increased availability Operational Increased maintenance Pre alarm
- 41. Second Line ofOver Speed Protection If First fails Limit Peak Speed Below 120%