US20040081549A1 - Method and apparatus for improving steam turbine control - Google Patents
Method and apparatus for improving steam turbine control Download PDFInfo
- Publication number
- US20040081549A1 US20040081549A1 US10/281,846 US28184602A US2004081549A1 US 20040081549 A1 US20040081549 A1 US 20040081549A1 US 28184602 A US28184602 A US 28184602A US 2004081549 A1 US2004081549 A1 US 2004081549A1
- Authority
- US
- United States
- Prior art keywords
- steam
- valve actuator
- piston
- velocity
- set point
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D17/00—Regulating or controlling by varying flow
- F01D17/10—Final actuators
Definitions
- This invention relates generally to a method and apparatus for speed control of steam turbines. More specifically, the invention relates to a method for overcoming performance degradation attributed to a worn or defective electromechanical pilot-valve actuator assembly (a major component of the overall control system) by employing one or more additional digital controllers; consequently improving the accuracy, stability, and reliability of an integrated, turbomachinery speed-control system.
- a steam turbine control-system is equipped with an electromechanical pilot-valve actuator assembly regulated by at least one controller.
- This actuator drives a pilot valve used to manipulate a hydraulic steam-valve actuator that, in turn, modulates a steam valve, thereby controlling a turbine's speed.
- this particular control setup cannot fully satisfy quick-response requirements because of insufficient electromagnetic force needed to overcome inherent frictional forces and/or other restricting effects that can impede the pilot valve's linear motion. Accordingly, there is a need for a method of control that compensates for performance degradation of the overall integrated system brought about by insufficient pilot-valve response.
- a purpose of this invention is to provide a method for controlling the rate of steam flow through a turbine by monitoring the position of a pilot valve, in addition to monitoring the dynamics of a steam valve; then applying these data to compensate for the deficient action of an electromechanical pilot-valve actuator assembly.
- the pilot valve manipulates a hydraulically-driven, steam-valve actuator that modulates the steam valve through which steam passes into the turbine. Performance degradation can occur when a pilot-valve actuator assembly's operation is faulty due to impaired electromagnetic components, excessive friction, or contaminated oil.
- a speed-controller Proportional Integral Derivative (PID) algorithm produces an output value, based on the steam turbine's measured rotational-speed and a rotational-speed set point. This PID output value is compared with an actuator position, and the difference between them is then multiplied by a constant gain as a set point for a steam-valve velocity PID controller that uses the previously mentioned steam-valve actuator's piston velocity as its process variable.
- PID Proportional Integral Derivative
- a pilot-valve PID position controller is cascaded with the steam-valve velocity PID controller whose output is used as the pilot-valve position controller's set point. Subsequently, the pilot-valve position controller's output becomes the energizing signal for the pilot-valve actuator's primary coil, whereas the secondary coil is regulated by a separate Proportional Derivative (PD) control element.
- PD Proportional Derivative
- both coils are energized proportionately, or one coil may not be energized at all. But whenever the steam-valve actuator's response speed is not adequate, the energizing signal to the secondary coil (and possibly to the primary coil, as well) is quickly increased by a value corresponding to the difference between the required velocity of the steam-valve actuator's piston and the piston's actual velocity.
- FIG. 1 shows an integrated, turbomachinery speed-control system with a pilot-valve actuator assembly comprising two electromagnetic coils.
- FIG. 2 shows an integrated, turbomachinery speed-control system with a pilot-valve actuator assembly comprising a single electromagnetic coil.
- FIG. 3 shows an integrated, turbomachinery speed-control system with a pilot-valve actuator assembly comprising two electromagnetic coils energized by separate constant-multipliers.
- an integrated turbomachinery control system should be capable of compensating for the possibility of faulty operation of an electromechanical pilot-valve actuator assembly by monitoring and controlling the position of a pilot valve, as well as assessing the velocity of a steam-valve actuator's piston.
- FIG. 1 shows a steam turbine 101 complete with its speed-control system incorporating a rotational-speed PID controller (#1) 102 that monitors a speed set point (SP) 103 , in addition to rotational-speed measurements obtained by a speed transmitter (N) 104 .
- This #1 controller 102 inputs (X SP ) to a #1 summation block 105 that receives an additional signal from a transmitter (XMTR 1) 106 monitoring the position (X) of a steam-valve actuator's 107 piston.
- the steam-valve actuator is connected to a steam valve 108 used to regulate the flow of steam passing through the turbine 101 .
- When steam exits the turbine it passes into a condenser 109 or other process; additionally, the turbine is used to drive a load 110 (shown as a generator), but this invention is not restricted to a particular load.
- the #1 summation block's 105 calculated value ( ⁇ X) is directed to a logic module 111 [by way of a constant multiplier (K 1 ) 112 as a velocity set point, V SP In 1] and also to a steam-valve velocity PID controller (#2) 113 [by way of a second, constant multiplier (K 2 ) 114 ]; note that K 1 ⁇ K 2 .
- XMTR 1 106 In addition to inputting to #1 summation block 105 , XMTR 1 106 also inputs to a time-derivative function block (d/dt) 115 that calculates the steam-valve actuator's piston velocity (V) from the measured values of the piston's position (X). This velocity value (V In 2) is then allocated to the logic module 111 and to controller #2 113 whose output is directed to a third PID controller (#3) 116 .
- d/dt time-derivative function block
- Controller #3 monitors the position of a pilot valve 117 [by way of a second transmitter (XMTR 2) 118 ]; this #3 controller's output is connected to the primary coil 119 of an electromechanical actuator (ACTR) 120 that drives the pilot valve 117 which, by way of hydraulic fluid, activates the steam-valve actuator 107 causing a change in its piston's position (X).
- XMTR 2 118 also sends a pilot-valve position signal to the logic module (In 3) 111 .
- the turbine-generator set participates in control of the turbine's rotational speed (which is proportional to the generator's 110 rotational speed).
- the speed transmitter's 104 output signal (N) will vary which, in turn, results in a modified signal from PID controller #1 102 to the #1 summation block 105 .
- #1 summation block's output is zero; however, a nonzero output (augmented by K 2 114 ) is the velocity set point for PID controller #2 113 .
- This velocity set point is for the steam-valve actuator 107 , and when compared with a velocity value (V) 115 it is transformed (through the PID algorithm) by controller #2 113 into a position set point for the pilot valve 117 whose response directly energizes the primary coil 119 . Subsequently, a feedback value for the pilot valve's 117 position (by way of the electromechanical actuator 120 ) is transmitted from XMTR 2 118 as the process variable for controller #3 116 .
- the control system responds by ultimately changing the signals to at least the primary coil of the pilot-valve actuator 120 .
- This action initiates a modulation of the pilot valve 117 , causing a change in the position of the steam-valve actuator's 107 piston.
- the steam valve 108 assumes a new position corresponding to the required control-system response.
- a change in the steam-valve actuator's 107 piston position translates to a change in the turbine's rotational speed.
- V SP K 1 ⁇ X
- ⁇ X steam-valve actuator's piston-position deviation (X SP ⁇ X)
- Out 1 is used directly as a set point for controller #4 121 [shown utilizing a Proportional Derivative (PD) algorithm].
- Out 2 is passed on to controller #4 as a process variable.
- the secondary coil 122 is energized by a value proportional to that used to energize the primary coil 119 .
- the secondary coil's energizing signal is inputted from the #2 summation block 124 that combines a constant-of-proportionality (K 3 ) 123 with the output of controller #4 121 .
- K 3 constant-of-proportionality
- the value of K 3 is zero, in which case the secondary coil 122 is energized only when Condition 2 is true, or when the value of K 3 is 1.0 so that the secondary coil is energized the same as the primary coil 119 .
- the value of K 3 123 can be chosen to be any value producing the desired response from the electromechanical actuator 120 .
- the secondary coil 122 is energized to the level “K 3 times the output of controller #3 116 ” (this product may be zero) because both the process variable and the set point for controller #4 121 are zero. (The derivative term could be nonzero shortly after the process variable and the set points become zero, but it would quickly become zero.)
- controller #4's 121 set point equals the difference between the steam-valve actuator's piston-velocity set point and the piston's velocity. As soon as Condition 2 becomes initially satisfied, the process variable for controller #4 121 will be zero because In 3 m is equal (at that instant) to In 3.
- FIG. 2 shows the output signals from PID controller #3 116 and PD controller #4 121 being summed in block #2 124 : the single coil 201 is energized, based on the summation block's signal. All other aspects of the control scheme are the same.
- FIG. 3 displays a third embodiment employing multiple coils 119 , 122 in which the signals used to energize the respective coils are multiplied by factors K 3 123 and K 4 301 .
- the two coils are energized proportionally, each contributing to the electromagnetic force required to activate the electromechanical pilot-valve actuator 120 , regardless of which Condition (1 or 2) is in effect. All other aspects of the control scheme are the same.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Turbines (AREA)
Abstract
Description
- This invention relates generally to a method and apparatus for speed control of steam turbines. More specifically, the invention relates to a method for overcoming performance degradation attributed to a worn or defective electromechanical pilot-valve actuator assembly (a major component of the overall control system) by employing one or more additional digital controllers; consequently improving the accuracy, stability, and reliability of an integrated, turbomachinery speed-control system.
- Highly-reliable, generator speed-control is required nowadays to meet the stringent requirements for utility-grid frequency; furthermore, recurrent changes in energy-demand dictate prompt, control-system response. If control-system response is not sufficient during transients, a discrepancy will exist between a generator's rotational speed and the generator speed required to match the utility-grid frequency, in spite of the control system's steady-state accuracy.
- Typically, a steam turbine control-system is equipped with an electromechanical pilot-valve actuator assembly regulated by at least one controller. This actuator drives a pilot valve used to manipulate a hydraulic steam-valve actuator that, in turn, modulates a steam valve, thereby controlling a turbine's speed. At times, however, this particular control setup cannot fully satisfy quick-response requirements because of insufficient electromagnetic force needed to overcome inherent frictional forces and/or other restricting effects that can impede the pilot valve's linear motion. Accordingly, there is a need for a method of control that compensates for performance degradation of the overall integrated system brought about by insufficient pilot-valve response.
- A purpose of this invention is to provide a method for controlling the rate of steam flow through a turbine by monitoring the position of a pilot valve, in addition to monitoring the dynamics of a steam valve; then applying these data to compensate for the deficient action of an electromechanical pilot-valve actuator assembly.
- The pilot valve manipulates a hydraulically-driven, steam-valve actuator that modulates the steam valve through which steam passes into the turbine. Performance degradation can occur when a pilot-valve actuator assembly's operation is faulty due to impaired electromagnetic components, excessive friction, or contaminated oil.
- The aforementioned purpose is accomplished, in part, by employing a unique control system dedicated to pilot-valve actuators which are equipped with a mix of individually-energized induction coils: a single coil or multiple coils (usually a primary and a secondary) whose respective control setups utilize the steam-valve actuator's piston velocity as a process variable.
- Using a dual-coil configuration as an example, a speed-controller Proportional Integral Derivative (PID) algorithm produces an output value, based on the steam turbine's measured rotational-speed and a rotational-speed set point. This PID output value is compared with an actuator position, and the difference between them is then multiplied by a constant gain as a set point for a steam-valve velocity PID controller that uses the previously mentioned steam-valve actuator's piston velocity as its process variable.
- Next, a pilot-valve PID position controller is cascaded with the steam-valve velocity PID controller whose output is used as the pilot-valve position controller's set point. Subsequently, the pilot-valve position controller's output becomes the energizing signal for the pilot-valve actuator's primary coil, whereas the secondary coil is regulated by a separate Proportional Derivative (PD) control element.
- Finally, when the speed at which the steam-valve actuator responds is adequate, both coils are energized proportionately, or one coil may not be energized at all. But whenever the steam-valve actuator's response speed is not adequate, the energizing signal to the secondary coil (and possibly to the primary coil, as well) is quickly increased by a value corresponding to the difference between the required velocity of the steam-valve actuator's piston and the piston's actual velocity.
- FIG. 1 shows an integrated, turbomachinery speed-control system with a pilot-valve actuator assembly comprising two electromagnetic coils.
- FIG. 2 shows an integrated, turbomachinery speed-control system with a pilot-valve actuator assembly comprising a single electromagnetic coil.
- FIG. 3 shows an integrated, turbomachinery speed-control system with a pilot-valve actuator assembly comprising two electromagnetic coils energized by separate constant-multipliers.
- To maintain reliable, accurate, and stable speed-control of a constituent steam turbine, an integrated turbomachinery control system should be capable of compensating for the possibility of faulty operation of an electromechanical pilot-valve actuator assembly by monitoring and controlling the position of a pilot valve, as well as assessing the velocity of a steam-valve actuator's piston.
- FIG. 1 shows a
steam turbine 101 complete with its speed-control system incorporating a rotational-speed PID controller (#1) 102 that monitors a speed set point (SP) 103, in addition to rotational-speed measurements obtained by a speed transmitter (N) 104. This #1controller 102 inputs (XSP) to a #1summation block 105 that receives an additional signal from a transmitter (XMTR 1) 106 monitoring the position (X) of a steam-valve actuator's 107 piston. The steam-valve actuator is connected to asteam valve 108 used to regulate the flow of steam passing through theturbine 101. When steam exits the turbine, it passes into acondenser 109 or other process; additionally, the turbine is used to drive a load 110 (shown as a generator), but this invention is not restricted to a particular load. - The #1 summation block's105 calculated value (ΔX) is directed to a logic module 111 [by way of a constant multiplier (K1) 112 as a velocity set point, VSP In 1] and also to a steam-valve velocity PID controller (#2) 113 [by way of a second, constant multiplier (K2) 114]; note that K1<K2.
- In addition to inputting to #1
summation block 105,XMTR 1 106 also inputs to a time-derivative function block (d/dt) 115 that calculates the steam-valve actuator's piston velocity (V) from the measured values of the piston's position (X). This velocity value (V In 2) is then allocated to thelogic module 111 and tocontroller # 2 113 whose output is directed to a third PID controller (#3) 116.Controller # 3 monitors the position of a pilot valve 117 [by way of a second transmitter (XMTR 2) 118]; this #3 controller's output is connected to theprimary coil 119 of an electromechanical actuator (ACTR) 120 that drives thepilot valve 117 which, by way of hydraulic fluid, activates the steam-valve actuator 107 causing a change in its piston's position (X). XMTR 2 118 also sends a pilot-valve position signal to the logic module (In 3) 111. - In its illustrated configuration, the turbine-generator set participates in control of the turbine's rotational speed (which is proportional to the generator's110 rotational speed). When changes in the turbine's rotational speed occur, the speed transmitter's 104 output signal (N) will vary which, in turn, results in a modified signal from
PID controller # 1 102 to the #1summation block 105. While in a steady-state (equilibrium) condition, #1 summation block's output is zero; however, a nonzero output (augmented by K2 114) is the velocity set point forPID controller # 2 113. This velocity set point is for the steam-valve actuator 107, and when compared with a velocity value (V) 115 it is transformed (through the PID algorithm) bycontroller # 2 113 into a position set point for thepilot valve 117 whose response directly energizes theprimary coil 119. Subsequently, a feedback value for the pilot valve's 117 position (by way of the electromechanical actuator 120) is transmitted from XMTR 2 118 as the process variable forcontroller # 3 116. - When the turbine's rotational speed (N) changes, the control system responds by ultimately changing the signals to at least the primary coil of the pilot-
valve actuator 120. This action, in turn, initiates a modulation of thepilot valve 117, causing a change in the position of the steam-valve actuator's 107 piston. Accordingly, thesteam valve 108 assumes a new position corresponding to the required control-system response. A change in the steam-valve actuator's 107 piston position translates to a change in the turbine's rotational speed. Simultaneously, the three inputs (VSP In 1, V In 2, and In 3) to thelogic module 111 are used to calculate two outputs as follows: - where
- VSP=K1ΔX
- ΔX=steam-valve actuator's piston-position deviation (XSP−X)
- V=dX/dt
- In 3=pilot-valve position signal (inputted to logic module111)
- In 3m=In 3 signal stored in memory when
Condition 2 first becomes true. This value remains constant untilCondition 2, for which this value is being used, is no longer true. -
Conditions - Out 1 is used directly as a set point for
controller # 4 121 [shown utilizing a Proportional Derivative (PD) algorithm]. Out 2 is passed on tocontroller # 4 as a process variable. - In one embodiment of this invention (FIG. 1), the
secondary coil 122 is energized by a value proportional to that used to energize theprimary coil 119. The secondary coil's energizing signal is inputted from the #2summation block 124 that combines a constant-of-proportionality (K3) 123 with the output ofcontroller # 4 121. Usually, the value of K3 is zero, in which case thesecondary coil 122 is energized only whenCondition 2 is true, or when the value of K3 is 1.0 so that the secondary coil is energized the same as theprimary coil 119. In reality, the value ofK 3 123 can be chosen to be any value producing the desired response from theelectromechanical actuator 120. - As long as
Condition 1 is true, thesecondary coil 122 is energized to the level “K3 times the output ofcontroller # 3 116” (this product may be zero) because both the process variable and the set point forcontroller # 4 121 are zero. (The derivative term could be nonzero shortly after the process variable and the set points become zero, but it would quickly become zero.) - If
Condition 2 is satisfied,controller # 4's 121 set point equals the difference between the steam-valve actuator's piston-velocity set point and the piston's velocity. As soon asCondition 2 becomes initially satisfied, the process variable forcontroller # 4 121 will be zero because In 3m is equal (at that instant) to In 3. - As time progresses, while
Condition 2 is satisfied, In 3 will vary while In 3m remains constant; for this reason,controller # 4's 121 process variable will deviate from zero. With additional electromagnetic force, due to the now energizedsecondary coil 122, the steam-valve actuator's piston velocity will quickly meet or exceed the required velocity (VSP); at which point,Condition 2 will no longer be satisfied. - A second embodiment (FIG. 2) shows the output signals from
PID controller # 3 116 andPD controller # 4 121 being summed inblock # 2 124: thesingle coil 201 is energized, based on the summation block's signal. All other aspects of the control scheme are the same. - FIG. 3 displays a third embodiment employing
multiple coils factors K 3 123 andK 4 301. Here, the two coils are energized proportionally, each contributing to the electromagnetic force required to activate the electromechanical pilot-valve actuator 120, regardless of which Condition (1 or 2) is in effect. All other aspects of the control scheme are the same. - The turbine-controlled variable described herein is not restrictive nor unique to this invention; in which case, other control-system variables may be considered. Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
Claims (30)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/281,846 US20040081549A1 (en) | 2002-10-28 | 2002-10-28 | Method and apparatus for improving steam turbine control |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/281,846 US20040081549A1 (en) | 2002-10-28 | 2002-10-28 | Method and apparatus for improving steam turbine control |
Publications (1)
Publication Number | Publication Date |
---|---|
US20040081549A1 true US20040081549A1 (en) | 2004-04-29 |
Family
ID=32107254
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/281,846 Abandoned US20040081549A1 (en) | 2002-10-28 | 2002-10-28 | Method and apparatus for improving steam turbine control |
Country Status (1)
Country | Link |
---|---|
US (1) | US20040081549A1 (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7155367B1 (en) | 2005-01-25 | 2006-12-26 | Continuous Control Solutions, Inc. | Method for evaluating relative efficiency of equipment |
US20080029261A1 (en) * | 2006-08-01 | 2008-02-07 | Emerson Process Management Power & Water Solutions, Inc. | Steam Temperature Control Using Integrated Function Block |
US20100042261A1 (en) * | 2008-08-12 | 2010-02-18 | Kabushiki Kaisha Toshiba | Plant controlling system and plant controlling method |
EA013903B1 (en) * | 2009-12-28 | 2010-08-30 | Закрытое Акционерное Общество "Диаконт" | A method for steam control valve positioning with dynamic “zero” correction used in a steam turbine governor system |
CN102588011A (en) * | 2012-03-06 | 2012-07-18 | 山西省电力公司电力科学研究院 | Steam engine main control system of large fossil power unit |
CN103216826A (en) * | 2013-04-02 | 2013-07-24 | 国家电网公司 | Main steam pressure self-adaptive predictor of generator set of circulating fluidized bed boiler |
US20140260249A1 (en) * | 2013-03-13 | 2014-09-18 | Statistics & Control, Inc. | Method and apparatus for improving electro-hydraulic and electro-mechanical integrated control systems of a steam turbine |
US10436488B2 (en) | 2002-12-09 | 2019-10-08 | Hudson Technologies Inc. | Method and apparatus for optimizing refrigeration systems |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3709626A (en) * | 1971-09-16 | 1973-01-09 | Gen Electric | Digital analog electrohydraulic turbine control system |
US4585205A (en) * | 1984-06-13 | 1986-04-29 | General Electric Company | Fast opening valve apparatus |
US5295783A (en) * | 1993-04-19 | 1994-03-22 | Conmec, Inc. | System and method for regulating the speed of a steam turbine by controlling the turbine valve rack actuator |
-
2002
- 2002-10-28 US US10/281,846 patent/US20040081549A1/en not_active Abandoned
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3709626A (en) * | 1971-09-16 | 1973-01-09 | Gen Electric | Digital analog electrohydraulic turbine control system |
US4585205A (en) * | 1984-06-13 | 1986-04-29 | General Electric Company | Fast opening valve apparatus |
US5295783A (en) * | 1993-04-19 | 1994-03-22 | Conmec, Inc. | System and method for regulating the speed of a steam turbine by controlling the turbine valve rack actuator |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10436488B2 (en) | 2002-12-09 | 2019-10-08 | Hudson Technologies Inc. | Method and apparatus for optimizing refrigeration systems |
US7155367B1 (en) | 2005-01-25 | 2006-12-26 | Continuous Control Solutions, Inc. | Method for evaluating relative efficiency of equipment |
US20080029261A1 (en) * | 2006-08-01 | 2008-02-07 | Emerson Process Management Power & Water Solutions, Inc. | Steam Temperature Control Using Integrated Function Block |
US7668623B2 (en) * | 2006-08-01 | 2010-02-23 | Emerson Process Management Power & Water Solutions, Inc. | Steam temperature control using integrated function block |
US20100042261A1 (en) * | 2008-08-12 | 2010-02-18 | Kabushiki Kaisha Toshiba | Plant controlling system and plant controlling method |
US8219218B2 (en) * | 2008-08-12 | 2012-07-10 | Kabushiki Kaisha Toshiba | Plant controlling system and plant controlling method |
EA013903B1 (en) * | 2009-12-28 | 2010-08-30 | Закрытое Акционерное Общество "Диаконт" | A method for steam control valve positioning with dynamic “zero” correction used in a steam turbine governor system |
WO2011081569A1 (en) * | 2009-12-28 | 2011-07-07 | Asylkhan Narimanovich Kushbasov | Method of adjusting position of riding cutoff valve |
CN102588011A (en) * | 2012-03-06 | 2012-07-18 | 山西省电力公司电力科学研究院 | Steam engine main control system of large fossil power unit |
US20140260249A1 (en) * | 2013-03-13 | 2014-09-18 | Statistics & Control, Inc. | Method and apparatus for improving electro-hydraulic and electro-mechanical integrated control systems of a steam turbine |
US9103233B2 (en) * | 2013-03-13 | 2015-08-11 | Statistics & Control, Inc. | Method and apparatus for improving electro-hydraulic and electro-mechanical integrated control systems of a steam turbine |
CN103216826A (en) * | 2013-04-02 | 2013-07-24 | 国家电网公司 | Main steam pressure self-adaptive predictor of generator set of circulating fluidized bed boiler |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0587902B1 (en) | Hydraulically driving system | |
EP2075474B1 (en) | Degraded actuator detection | |
CA1085493A (en) | Adaptive control system using position feedback | |
JP2647852B2 (en) | Method and apparatus for measuring fluid flow characteristics | |
Borello et al. | A prognostic model for electrohydraulic servovalves | |
KR900702146A (en) | Hydraulic drive system of construction machinery | |
US5609465A (en) | Method and apparatus for overspeed prevention using open-loop response | |
JPH07509048A (en) | Control device for hydraulic drives or actuators | |
US20040081549A1 (en) | Method and apparatus for improving steam turbine control | |
US4644748A (en) | Constant speed hydraulic drive | |
US4270357A (en) | Turbine control | |
US4612616A (en) | Fuel control system for a gas turbine engine | |
US5189611A (en) | Temperature compensation technique for a continuously variable transmission control system | |
US4543782A (en) | Gas turbine engine fuel control systems | |
US6719523B2 (en) | Method and apparatus for steam turbine speed control | |
US6767178B2 (en) | Response time of a steam turbine speed-control system | |
JPS63242741A (en) | Temperature compensation method of continuous variable transmission control system | |
US3820321A (en) | Acceleration control for gas turbine engine | |
US4967124A (en) | Servo control apparatus | |
US3856034A (en) | Flow control valve | |
EP0186092B1 (en) | Power transmission | |
CN114382754A (en) | Method for operating a hydraulic drive | |
CA1178069A (en) | Gas turbine engine fuel control system | |
JPH03303A (en) | Method and apparatus for compensating pressure fluid characteristic of servo valve in electrohydraulic servo device | |
EP4102208A1 (en) | Densimeter |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: COMPRESSOR CONTROLS CORPORATION, IOWA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SHAPIRO, VADIM;DROB, DMITRY;REEL/FRAME:013711/0332 Effective date: 20021023 |
|
AS | Assignment |
Owner name: ROPINTASSCO HOLDINGS, L.P., GEORGIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ROPER HOLDINGS, INC.;REEL/FRAME:014805/0957 Effective date: 20031128 |
|
AS | Assignment |
Owner name: JPMORGAN CHASE BANK, TEXAS Free format text: SECURITY AGREEMENT;ASSIGNOR:ROPINTASSCO HOLDINGS, L.P.;REEL/FRAME:014981/0256 Effective date: 20040206 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE |
|
AS | Assignment |
Owner name: ROPER HOLDINGS, INC., DELAWARE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ROPINTASSCO HOLDINGS, L.P.;REEL/FRAME:017314/0868 Effective date: 20060306 |
|
AS | Assignment |
Owner name: ROPINTASSCO HOLDINGS, L.P., FLORIDA Free format text: TERMINATION AND RELEASE OF SECURITY;ASSIGNOR:JPMORGAN CHASE BANK, N.A.;REEL/FRAME:021281/0956 Effective date: 20080701 |