JP3374745B2 - Process control device and control method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to state variables such as pressure, water level, flow rate, and temperature of a process (hereinafter referred to as "process") by cooperatively controlling a first control valve and a second control valve arranged in parallel with each other. , "Process state quantity") and a control method therefor, particularly, main steam, auxiliary steam, combustion gas, exhaust gas, fuel, condensate of thermal power plants and nuclear power plants, The present invention relates to a process control device and a control method for controlling process state quantities such as water supply and water storage.

[0002]

2. Description of the Related Art In process control of a thermal power plant or a nuclear power plant, a large-capacity valve and a small-capacity valve are arranged in parallel with each other and the large-capacity valve and the small-capacity valve are controlled in a coordinated manner. The state quantity is controlled. That is, when the change width of the process state quantity is small, the small capacity valve is positively opened / closed, and when the change width of the process state quantity is large, the large capacity valve is actively opened / closed. .

For example, in Japanese Unexamined Patent Publication No. 56-82303, a second control valve (large capacity) performs feed-forward control according to a temperature difference between a high temperature side and a low temperature side in a steam generator, If the control valve (small capacity) performs feedback control by three elements of the water level of the closed container, the steam flow rate, and the feed water flow rate, and if the opening degree of the first control valve becomes equal to or larger than a set opening degree,
The second control valve is forcibly opened, and when the first control valve falls below a certain set opening, the second control valve is forcibly opened by the second control valve.
There is described a water level control device for producing a signal on the side of closing the control valve of the above and adding this signal to the output signal of the first function generator to control the second control valve.

Further, in Japanese Patent Laid-Open No. 61-180809, the deviation between the detected water level signal and the water level set value is proportionally / integrally calculated to control the first control valve (small capacity). The opening of the first control valve is opened by controlling the second control valve (large capacity) by proportionally and integrating the deviation between the opening signal transmitted to the first control valve and the set value of the opening. There is described a water level control device that controls the opening degree of the second control valve so as to obtain the degree set value.

Further, in Japanese Patent Laid-Open No. 52-64502, a child valve (small capacity) is used at the time of starting and stopping a plant, and the child valve is closed as the load increases and the parent valve (large capacity) is opened. Thus, a deaerator level control device for controlling the deaerator level by switching from the child valve to the parent valve is described.

Further, in Japanese Patent Laid-Open No. 59-87503, a common controller controls a large capacity control valve and a small capacity control valve (split range control), and the output value of the controller is the first signal level. There is described a process control device for increasing the control gain of the large capacity control valve when the temperature reaches the above, and for returning the control gain of the large capacity control valve when the output value of the controller returns to the second signal level.

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention JP-A-56-82303
When the opening of the first control valve becomes equal to or larger than a set opening as in the invention described in Japanese Patent Laid-Open Publication No. 2004-242242, the second function generator forcibly opens the second control valve. , The amount of process increases rapidly, and the water level of the steam generator exceeds the target set water level. When the water level of the steam generator exceeds the target set water level, the feedback control of the first control valve adjusts the opening degree of the first control valve in the direction of decreasing. Then, when the opening of the first control valve becomes equal to or less than a set opening value, the second function generator forcibly closes the second control valve, and the process amount sharply decreases, resulting in The water level of the generator falls below the target set water level. When the water level of the steam generator falls below the target set water level due to a sudden decrease in the process amount, the feedback control of the first control valve adjusts the opening of the first control valve in the direction of increasing again. As described above, particularly when the change width of the process state quantity (water level of the steam generator) is large, there is a problem that the first control valve and the second control valve cannot be coordinated and the process state quantity is not stable.

Further, as in the invention described in JP-A-61-180809, the opening of the second control valve is controlled so that the opening of the first control valve becomes the set opening. Therefore, when the required flow rate of the plant is determined, the opening of the first control valve and the opening of the second control valve are uniquely determined. When the required flow rate, pressure, temperature, etc. of the plant change even with a small amount, the opening of the first control valve changes, and the opening of the first control valve deviates from the set opening accordingly. As a result, the opening degree of the second control valve also changes. At this time, if the PI control gain of the controller of the second control valve is small, the change width of the first control valve increases, The deviation between the opening degree of the first control valve, which is the reference signal of the control valve, and the set opening degree increases, and the change width of the second control valve increases. That is, the feedback control is continued by the first control valve and the second control valve periodically increases and decreases the opening degree even when the plant is under constant operation (eg rated operation) under high load. And, even when the increase / decrease width of the second opening is the minimum, the valve opening will be changed stepwise by the dead zone of the second control valve,
There is a problem that the range of process change becomes large and the process state quantity is not stable.

Further, Japanese Patent Application Laid-Open No. 52-64502 and Japanese Patent Application Laid-Open No.
Similarly, in the invention described in JP-A-59-87503,
Even when the plant is under constant operation with a high load, the valve opening changes in steps due to the dead zone of the large capacity valve, the process change width increases and the process state quantity becomes unstable. .

An object of the present invention is to change the target value of the process state quantity of the second control valve (large control valve) according to the valve opening of the first control valve (small control valve). By doing so, it is an object of the present invention to provide a process control device and a control method thereof in which control interference between the first control valve and the second control valve is suppressed.

[0011]

In order to achieve the above object, the process control method of the present invention is arranged in parallel with each other so that the process state quantity corresponds to a preset target value of the process state quantity. The large-capacity control valve and the small-capacity control valve are controlled to control the process state quantity.
Further, when the small capacity control valve becomes equal to or larger than a preset first predetermined valve opening degree, or when the first predetermined valve opening is performed.
When the temperature exceeds a predetermined value, the target value of the process state quantity of the large capacity control valve is increased, and the small capacity control valve is set to a second predetermined value equal to or smaller than the first predetermined valve opening degree. The target value of the process state quantity of the large-capacity control valve is reduced when the valve opening degree is less than or equal to or less than the second predetermined valve opening degree .

[0012] Alternatively, in order to achieve the above object, the process control method of the present invention has a large capacity arranged in parallel with each other so that the process state quantity corresponds to a preset target value of the process state quantity. A control valve and a small capacity control valve are controlled to control the process state quantity. Further, when the small-capacity control valve is equal to or smaller than a preset first predetermined valve opening or is smaller than the first predetermined valve opening , the large-capacity The target value of the process state quantity of the control valve is reduced, and the control valve of the small capacity is set to a second predetermined valve opening or more set to the first predetermined valve opening or more .
Or when the second predetermined valve opening is exceeded, the target value of the process state quantity of the large capacity control valve is increased.

Alternatively, in order to achieve the above object, the process control method of the present invention has a large capacity, which is arranged in parallel with each other so that the process state quantity corresponds to a preset target value of the process state quantity. A control valve and a small capacity control valve are controlled to control the process state quantity. Further, when the small-capacity control valve is out of the preset first predetermined valve opening range, the target value of the process state amount of the large-capacity control valve is changed to When the control valve comes within the second predetermined opening range set within the first predetermined valve opening range, the target value of the process state quantity of the large capacity control valve is returned to the original value. Preferably, when the small capacity control valve is out of the first predetermined opening range, the control gain of the controller for controlling the large capacity control valve is increased. Further, preferably, when the small capacity control valve is within the second predetermined opening range, the control gain of the controller for controlling the large capacity control valve is reduced.

[0014]

In order to achieve the above object, the process control device of the present invention comprises a first control valve and a second control valve arranged in parallel with each other, a transmitter for detecting a process state quantity, A setting unit that sets a target value of the process state quantity; and a first control valve that controls the first control valve based on a detected value of the process state quantity detected by the transmitter and a target value of the process state quantity. No. 1 controller, a second controller that controls the second control valve based on the detected value of the process state quantity and the target value of the process state quantity, and the opening degree of the first control valve. The target process state quantity changing unit changes the target value of the process state quantity of the second controller.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

A coordinated control system is adopted in which a second control valve having a relatively large capacity and a first control valve having a relatively small capacity arranged in parallel with each other are controlled to control the process state quantity. Both the control valve and the second control valve employ feedback control for performing integral + proportional calculation based on the detected process state quantity, and the control gain of the second controller is set to be smaller than that of the first controller. Set smaller.

When the process state quantity is stable (constant), the target value of the first control valve and the target value of the second control valve are made the same. Then, the process state quantity changes, and the opening degree of the first control valve changes to the first specified range (for example, 10% to
90%), the target value of the second control valve is made larger (or smaller) than the target value of the first control valve.
In addition, the second regulation range (for example, 30% to 70%) in which the opening degree of the first control valve is set within the first regulation range
When the value becomes within the range, the target value of the second control valve is reduced (or increased), that is, the target value of the second control valve is returned to the original value, and the target value of the second control valve is set to the first value. Same as the target value of the control valve. That is, the first control valve corresponds to the upper limit of the first specified range and has a first predetermined valve opening (for example, 90 degrees).
%) Or more or more, the target value of the second control valve is made larger than the target value of the first control valve, and the first control valve corresponds to the upper limit value of the second specified range. When the valve opening degree of 2 is equal to or smaller than a predetermined valve opening degree (for example, 70%) or becomes smaller, the target value of the second control valve is decreased, that is, the target value of the second control valve is returned to the original value. On the other hand, when the first control valve is equal to or smaller than the first predetermined valve opening (for example, 10%) corresponding to the lower limit value of the first specified range or is small, the target value of the second control valve is set to the first value. When the first control valve is smaller than the target value of the first control valve, and the first control valve is equal to or larger than a second predetermined valve opening (for example, 30%) corresponding to the lower limit value of the second specified range, or becomes larger. And increase the target value of the second control valve, that is, the second
Return the target value of the control valve of. The first specified range and the second specified range may be the same.

When the control gain of the second controller for controlling the second control valve is set to a minimum value as compared with the control gain of the first controller for controlling the first control valve, the second control valve is set. The sensitivity of the feedback control is reduced and the opening degree of the second control valve does not change so much, and the process state quantity is controlled by only the first control valve. That is, when the process state quantity changes slightly, the process state quantity is controlled only by the first control valve having a relatively small valve capacity. On the other hand, when the change width of the process state amount is large, the opening degree of the first control valve is within the first specified range (for example, 10% to 90%).
%) Outside, the target value of the second control valve is changed as described above, and the deviation between the target value and the detected value of the second control valve becomes large, and the second control valve having a relatively large capacity is Is controlled to be large (or small). As a result, the process state quantity changes significantly, and conversely the opening of the first control valve is controlled in the closing direction (or opening direction), and eventually the opening of the first control valve falls within the second specified range. At the same time, the target value of the second control valve is also returned to the original value, and the feedback control of the second control valve becomes dull. After that, the first control valve is finely adjusted, and the process state quantity becomes stable.
As a result, it becomes possible to suppress the control interference between the first control valve and the second control valve and quickly control the process state quantity to its target value. Further, even if the load flow rate is any value, when the process state amount changes minutely, the process state amount can be finely adjusted by predominantly controlling the first control valve having a relatively small capacity. When the process state quantity changes significantly, the process state quantity is roughly adjusted by controlling the relatively small capacity first control valve and the relatively large capacity second control valve. Can
In other words, the process state quantity can be quickly and stably controlled to the target value regardless of the load flow rate and the variation range of the process state quantity.

Further preferably, the control gain of the second controller for controlling the second control valve may be changed in accordance with the change of the target value of the second control valve. That is, when the opening of the first control valve is within the first specified range, it is compared with the control gain of the second controller when the opening of the first control valve is outside the first specified range. Then, the control gain of the second controller is set to the minimum or zero. That is, when the opening degree of the first control valve is out of the first specified range, the control gain of the second controller is increased. When the second control valve operates and the opening of the first control valve acts in the closing direction (opening method), and the opening of the first control valve falls within the second specified range. Then, the control gain of the second controller is again set to the minimum or zero. This makes the first
When the control valve of 1 is within the first specified range, the sensitivity of the feedback control of the second control valve is further reduced. This makes it possible to further suppress control interference between the first control valve and the second control valve.

Furthermore, preferably, the opening degree of the second control valve is calculated on the basis of the load flow rate equivalent signal, and the second control valve is preliminarily controlled, so that the process state quantity can be more quickly brought to its target value. It becomes possible to control.

The first embodiment of the present invention will be described below.

FIG. 1 shows a first process control apparatus according to the present invention.
3 is a control block diagram of the embodiment of FIG. FIG. 2 shows a detailed control block diagram of the first control valve opening determination unit of the first embodiment of the process control device of the present invention. FIG. 3 shows a detailed control block diagram of the second target process state quantity compensating unit of the first embodiment of the process control apparatus of the present invention. FIG. 4 shows each state quantity (load flow rate, first control valve, second control valve supply flow rate, surge tank internal pressure, target set pressure, and the like) according to the first embodiment of the process control device of the present invention.
The time chart which compared the 1st control valve opening and the 2nd control valve opening) is shown. 1 to 4, 1 is a fuel gas supply header for supplying a fuel gas, 2 is a surge tank, 5 is a first control valve (small capacity valve) for adjusting the process amount, and 6 is a first amount valve for adjusting the process amount. 2 is a control valve (large capacity valve), 21 is a surge tank pressure transmitter that detects and transmits the pressure in the surge tank, and 40 is a process state by cooperatively controlling the first control valve and the second control valve. A controller for controlling the amount, 41 is a first controller for controlling the opening of the first control valve (calculating an opening command signal to the first control valve), 411 is a first control valve A first control calculation unit for calculating the opening command signal of
Reference numeral 1a is an addition / subtraction calculation unit that adds or subtracts an input signal and outputs the result, 411b is a proportional-plus-integration calculation unit that outputs a proportional + integral operation of the input signal, and 412 sets a process state amount targeted by the first control valve. A first target process state quantity setting unit, 42 is a second controller that controls the second control valve (calculates an opening command signal to the second control valve), and 421 is a second controller.
Control unit for calculating an opening command signal to the control valve, 421a is an addition / subtraction calculation unit for adding or subtracting an input signal and outputting the same, and 421b is a proportional integral for calculating a proportional + integral calculation of the input signal and outputting it. An arithmetic unit 422, a second target process state quantity setting unit 422a that sets a process state quantity targeted by the second control valve 6, an adder / subtractor calculator 422a that adds or subtracts an input signal, and outputs the added signal. A first determination for determining whether the valve opening degree of the first control valve is within the specified range or / and outside the specified range
Control valve opening determination unit, 431 is an input terminal, 432 is a first signal generation unit that outputs a signal of a preset value, 43
3 is a first monitor switch that outputs a predetermined signal based on the input signal, 434 is an output terminal, 435 is a second signal generator that outputs a signal of a preset value, and 436 is based on the input signal. A second monitor switch that outputs a predetermined signal, 437 is an output terminal, 47 is a second target process state quantity compensating section that changes the process state quantity targeted by the second control valve, and 47a is a first-order delay computing section. , 47b is an addition / subtraction arithmetic unit for adding or subtracting an input signal and outputting the same, 47c is an output terminal, 471 is an input terminal, 472 is a preset A side set value, 473 is a selection switch for selecting and outputting the input signal. 474 is a preset B side setting value, 475
Is a first-order delay calculation unit, 476 is an input terminal, 477 is a preset C-side set value, 478 is a selection switch for selecting and outputting an input signal, and 479 is a preset D-side set value.

The first embodiment shows an example in which the process control device of the present invention is applied to pressure control of a surge tank for fuel gas in a gas turbine power plant.

The flow rate of the fuel gas supplied from the fuel gas supply header 1 is controlled by the first adjusting valve 5 and the second adjusting valve 6 arranged in parallel with each other, and the surge tank 2
After being sent in, it is fed to the gas turbine combustor.

The valve capacity of the first control valve 5 (small capacity valve) ≦ the valve capacity of the second control valve 6 (large capacity valve). Further, preferably, the valve capacity of the first control valve 5: the valve capacity of the second control valve 6 = 1: 4.

In the surge tank pressure transmitter 21,
The pressure in the surge tank 2 is detected and transmitted to the control device 40. The control device 40 includes a first controller 41, a second controller 42, and a first control valve opening determination unit 43. The first controller 41 includes a first target process state quantity setting unit 412 and a first control calculation unit 411. The first control calculation unit 411 includes an addition / subtraction calculation unit 411a and a proportional integration calculation unit 411b. The second controller 42 includes a second target process state quantity setting unit 422 and a second control calculation unit 421. The second control calculation unit 421 includes an addition / subtraction calculation unit 421a.
And a proportional-plus-integral calculation unit 421d.

In the first target process state quantity setting unit 412, the target value (first target pressure signal) of the pressure in the surge tank 2 of the first control valve 5 (for example, 30.0 kg / cm).
² g) is set. In the addition / subtraction calculation unit 411a, the first
The pressure detection signal transmitted from the pressure transmitter 21 is subtracted from the target pressure signal of. In the proportional-plus-integral calculation unit 411b, the signal from the addition / subtraction calculation unit 411a (deviation signal between the pressure detection signal and the first target pressure signal) is proportional-integrated. An output signal from the proportional-plus-integral calculation unit 411b (a first opening command signal for instructing the opening of the first adjustment valve 5) is transmitted to the first adjustment valve 5 so that the first adjustment valve 5 is disclosed. Thus, the flow rate of the fuel gas (process) is controlled.

On the other hand, in the first control valve opening determination section,
It is determined that the first opening command signal is within the specified range and / or outside the specified range, and a signal is output according to the first opening command signal. Hereinafter, description will be made with reference to FIG. The first opening command signal is input from the input terminal 431 and transmitted to the first monitor switch 433 with a dead band and the second monitor switch 436 with a dead band.

When the signal at the input terminal 431 exceeds or exceeds the set value (for example, 90%) set in the first signal generator 432, the first monitor switch 433 is turned on and the signal is output. In addition, it is less than or equal to the set value set in the first signal generator 432, and the dead band (for example, 20%).
When it drops above or above, the first monitor switch 4
33 is reset (OFF), and no signal is output. That is, the setting value set in the first signal generation unit 432 is set to, for example, 90%, and the first monitor switch 433 is set.
If the disconnection difference is 20%, for example, and the signal at the input terminal 431 is 70% or less or is small, the first monitor switch 433 is reset. Then, the output signal of the first monitor switch 433 is output from the output terminal 434. The disconnection difference of the first monitor switch 433 may be 0%. First monitor switch 433
When the dead band difference of is 0%, the first monitor switch 433
Is set to ON, and the first monitor switch 433
Is the same as the set value that is reset.

On the other hand, when the signal at the input terminal 431 is less than or equal to the set value (for example, 10%) set in the second signal generator 435, the second monitor switch 436 is turned on.
The next signal is output. In addition, the second signal generator 435
If the value is equal to or more than the set value of and the dead band (for example, 20%) or more, the second monitor switch 436 is reset (OFF) and no signal is output. That is,
The setting value set in the second signal generator 435 is set to, for example, 1
If the contact difference of the second monitor switch 436 is set to 0% and the disconnection difference is set to, for example, 20%, the second monitor switch 436 is reset when the signal of the input terminal 431 is equal to or more than 30%. Second monitor switch 436
Is output from the output terminal 437. The dead band of the second monitor switch 436 may be 0%. When the disconnection difference of the second monitor switch 436 is 0%, the set value for turning on the second monitor switch 436 and the set value for resetting the second monitor switch 436 are the same. The output signal from the first control valve opening determination unit 43 is transmitted to the second target process state quantity adjustment unit 47. Hereinafter, description will be made with reference to FIG. The first
The output terminal 434 of the control valve opening determination unit 43 and the input terminal 471 of the second target process state amount correction unit 47 are connected, and the output terminal 43 of the first control valve opening determination unit 43.
7 and the input terminal 4 of the second target process state quantity compensator 47
76 is connected.

An output signal from the first control valve opening determination unit 43 is input from the input terminal 471, and the selection switch 4
73 is transmitted. When the valve opening of the first control valve 5 is equal to or more than or exceeds the set value set by the first signal generation unit 432 which is the upper limit value of the specified range, and the input signal from the input terminal 471 is ON (input When the signal from the terminal 471 is confirmed), a preset A side set value 472 (for example,
+ 1%) is selected and the setting signal is output. On the other hand, when the input signal from the input terminal 471 is OFF (when the signal from the input terminal 471 is not confirmed), the preset B side set value 474 (0%) is selected and the set signal is output. To be done. Then, the selection switch 473
From the first-order delay calculation unit 475,
It is transmitted to the addition / subtraction calculation unit 47b.

On the other hand, the output signal from the first control valve opening determination unit 43 is input from the input terminal 476 and transmitted to the selection switch 478. The valve opening of the first control valve 5 is
When the input signal from the input terminal 476 is ON (when the signal from the input terminal 476 is confirmed) when the input signal from the input terminal 476 is ON or smaller than the set value set by the second signal generator 435, which is the lower limit value of the specified range, A preset C-side set value 477 (for example, -1%) is selected and the set signal is output. On the other hand, when the input signal from the input terminal 476 is OFF (when the signal from the input terminal 476 is not confirmed)
Selects a preset D-side setting value 479 (0%) and outputs the setting signal. Then, the output signal from the selection switch 478 is transmitted to the addition / subtraction calculation unit 47b via the first-order delay calculation unit 47a. Addition / subtraction calculation unit 4
The output signal from 7b is output from the output terminal 47c.

The output signal from the second target process state quantity compensator 47 is transmitted to the addition / subtraction calculator 422a. In the addition / subtraction calculation unit 422a, the output signal from the first target process state quantity setting unit 412 and the output signal from the second target process state quantity adjusting unit 47 are added, and the added signal is used as the second control valve. It is output as a target value (second target pressure signal) of the pressure in the surge tank 2 of No. 6. Then, the output signal from the addition / subtraction calculation unit 422a is transmitted to the addition / subtraction calculation unit 421a of the second controller 42. The addition / subtraction calculation unit 421a subtracts the pressure detection signal from the second target pressure signal. In the proportional-plus-integral calculation unit 421d, the addition / subtraction calculation unit 42
A signal from 1a (a deviation signal between the pressure detection signal and the second target pressure signal) is proportionally / integrally calculated. Proportional-plus-integral calculation unit 4
The signal from 21d (the second opening command signal for instructing the opening to the second adjusting valve 6) is transmitted to the second adjusting valve 6, and the second adjusting valve 6 is opened and closed, so that the fuel gas Control the flow rate of (process).

Then, the first embodiment operates as follows.

When the opening of the first control valve 5 (first opening command signal) is within the specified range (first signal generator 43)
2 is less than or equal to the set value, and the second signal generator 4
If the value is equal to or more than the set value of 35), the output signal of the second target process state quantity correction unit 47 becomes zero.
The target value of the controller 42 (second target pressure signal) and the target value of the first controller 41 (first target pressure signal) are the same. The control gain of the first controller 41 (control gain of the proportional-plus-integral calculation unit 411b) is set to be more sensitive than the control gain of the second controller 42 (control gain of the proportional-integral calculation unit 421d). For example, the control gain of the first controller 41 is set to proportional gain = about 1.0 and the integration time = about 10 seconds, and the control gain of the second controller 42 is set to proportional gain = about
Set 0.2, integration time = about 30 seconds. This makes the first
When the opening degree of the control valve 5 is within the specified range and the pressure in the surge tank 2 slightly changes, the change degree of the opening of the second control valve 6 is small, and only the first control valve 5 changes the fuel. The gas flow rate will be controlled. Therefore, during constant plant load operation, control interference between the first control valve 5 and the second control valve 6 does not occur.

On the other hand, when the opening degree of the first control valve 5 is outside the specified range (when it is equal to or more than the set value of the first signal generating section 432, or when the set value of the second signal generating section 435 is set). If it is less than or smaller than the above, the signal is output from the first control valve opening determination unit 43. That is, when the setting value of the first signal generating unit 432 is equal to or more than or exceeds the setting value, the first monitor switch 433 is turned on. Then, when the opening degree of the first control valve 5 is equal to or larger than or equal to the set value of the first signal generator 432, the A side set value 472 is selected, and A
The side set value 472 is transmitted to the addition / subtraction calculation unit 422a. As a result, the second target pressure signal of the second control valve 6 changes to the first target pressure signal.
From the first target pressure signal of the control valve 5 of A side set value 472
The setting is changed to a higher value, and the proportional-plus-integral operation of the proportional-plus-integral calculation unit 421d functions to increase the opening of the second control valve 6 so that the opening of the first control valve 5 falls within the specified range. The opening degree of the second control valve 6 becomes gradually larger than that at the time, the flow rate of the fuel gas is increased, and the pressure in the surge tank 2 is increased. As a result, the first pressure detection signal becomes larger than the first target pressure signal, and the opening degree of the first control valve 5 is reduced by the feedback control to be within the specified range. Control of internal pressure becomes stable. In addition, the opening degree of the first control valve 5 is set to the second signal generator 435.
If it is less than or equal to the set value of, the C side set value 477 is selected, and the C side set value 477 is transmitted to the addition / subtraction calculation unit 422a. As a result, the second target pressure signal of the second control valve 6 is set lower than the first target pressure signal of the first control valve 5 by the C-side set value, and the proportional-plus-integral calculation unit 421d.
Of the second control valve 6 by the proportional + integral operation of the second control valve 6 to reduce the opening degree of the second control valve 6, and the opening degree of the second control valve 6 is smaller than that when the opening degree of the first control valve 5 is within the specified range. Becomes smaller and the fuel gas flow rate decreases. As a result, the opening of the first control valve 5 is increased to be within the specified opening, and the surge tank 2
Control of internal pressure becomes stable.

Next, a second embodiment of the present invention will be described.

FIG. 5 shows a second process control apparatus according to the present invention.
3 is a control block diagram of the embodiment of FIG. In FIG. 5, reference numeral 7 denotes a first control valve opening transmitter for detecting and transmitting the opening of the first control valve 5.

In the second embodiment, as the input signal of the first control valve opening determination unit 43, the first adjustment command signal is used instead of the first opening command signal in the first embodiment. In this example, the opening degree detection signal of the first control valve 5 transmitted from the valve opening degree transmitter 7 is used.

According to the second embodiment, as compared with the first embodiment, the actual opening degree of the first control valve 5 (detection) can be used to judge the opening degree of the first control valve 5. Value is used, the opening of the first control valve 5 can be accurately detected even when an abnormality occurs in the main body of the first control valve 5 such as stick, and the process state quantity can be stabilized. The effect of controlling by. Further, since the actual opening degree of the first control valve 5 is used for the determination of the opening degree of the first control valve 5, there is an effect that the accuracy of controlling the process state quantity is improved.

Next, a third embodiment of the present invention will be described.

FIG. 6 shows a third process control device according to the present invention.
3 is a control block diagram of the embodiment of FIG. FIG. 7 shows a detailed control block diagram of the second control gain-compensated control arithmetic unit of the third embodiment of the process control apparatus of the present invention. In FIGS. 6 and 7, reference numeral 48 denotes a second control gain-compensated control arithmetic unit for changing the control gain based on the input signal, 4
Reference numeral 81 is an input terminal, 482 is an input terminal, 483 is a logical sum (OR circuit) that outputs a signal when receiving at least one of a plurality of input signals, and 484 outputs a preset proportional gain. A first proportional gain setting unit,
485 is a selection switch for selecting and outputting an input signal, 4
Reference numeral 86 is a second proportional gain setting unit that outputs a preset proportional gain, 487 is a first-order delay calculation unit, 488 is a first integration time setting unit that outputs a preset integration time,
489 is a selection switch for selecting and outputting an input signal, 4
Reference numeral 8a is a second integration time setting unit that outputs a preset integration time, 48b is a first-order delay calculation unit, 48c is an input terminal, 48d is a proportional-plus-integral calculation unit that outputs a proportional + integral calculation of the input signal, and 48e. Indicates an output terminal. The setting value of the first proportional gain setting unit 484> the setting value of the second proportional gain setting unit 486, the setting value of the first integration time setting unit 488> the setting value of the second integration time setting unit 48a And

The third embodiment is an example in which a second control gain-compensated control operation unit 48 is added in place of the proportional-plus-integral operation unit 421d of the first embodiment. That is, this is an example in which the control gain of the second controller 42 is changed according to the value (setting change) of the second target pressure signal.

Output terminal 4 of the first control valve opening determination unit 43
34 and the input terminal 481 of the second control gain compensation control calculation section 48 are connected, and the output terminal 437 of the first control valve opening determination section 43 and the second control gain compensation control calculation section 48 are connected. Input terminal 482 is connected.

Then, the first control valve opening determination unit 43 determines that the opening of the first control valve 5 is out of the specified range, and the control calculation unit with second control gain compensation 48 makes the first adjustment. When the signal from the valve opening determination unit 43 is input (when at least one of the input terminal 481 and the input terminal 482 receives the signal), the selection switch 485 is set in the first proportional gain setting unit 484. A set value (for example, 1.0) is selected and transmitted to the proportional-plus-integral calculation unit 48d. Further, the selection switch 489 selects the set value (for example, 10 seconds) set in the first integration time setting unit 488, and the proportional-plus-integral calculation unit 4
Transmit to 8d.

When the first control valve opening determination unit 43 determines that the opening of the first control valve 5 is within the specified range, that is, the second control gain-compensated control calculation unit 48 determines the first The signal from the control valve opening determination unit 43 of is not input (input terminal 4
81 and the input terminal 482 input no signal), the selection switch 485 selects the set value (for example, 0.01) set in the second proportional gain setting unit 486, and the proportional-plus-integral calculation unit 48d. Communicate to. Further, the selection switch 489 selects the set value (for example, 100 minutes) set in the second integration time setting unit 48a and transmits it to the proportional-plus-integral calculation unit 48d. Then, the third embodiment operates as follows.

When the opening of the first control valve 5 is within the specified range, the target value of the second controller 42 and the target value of the first controller 41 are the same, for example, 30.0 kg / cm ^2. g, the control gain of the second controller 42 is set to a small proportional gain value (for example, 0.01 or 0), and a large integration time value (for example, 100 minutes or ∞). As a result, when the pressure in the surge tank 2 changes slightly, the second controller 42
The feedback gain of the second control valve 6 is almost temporarily stopped because the control gain of the second control valve 6 becomes extremely insensitive, and the opening degree of the second control valve 6 becomes substantially constant, so that the flow rate of the fuel gas (process) is increased. Will be controlled only by the first control valve 5. Therefore, during constant plant load operation, control interference between the first control valve 5 and the second control valve 6 does not occur.

If the opening degree of the first control valve 5 exceeds or exceeds the upper limit value (for example, 90%) of the specified range, the second
Of the adjusting meter 42 target values from e.g. 30kg / cm ² g, the first adjusting meter 41 target values for example 30kg / cm ² g about than about 0.5 kg / cm ² higher th 30.5 kg / cm ² g of And the control gain of the second controller 42 is changed to the proportional gain normal value.
(For example, 1.0) and change the integration time normal value (for example,
10 seconds). Thereby, even if the second control valve 6 and the first control valve 5 are simultaneously feedback-controlled,
Target value of the second controller 42 (for example, 30.5 kg / cm ² g)
Is the target value of the first controller 41 (for example, 30.0 kg / cm ²
g) It is higher than g), so it is
The second control valve 6 functions to increase the opening degree of the control valve 6 and the opening degree of the second control valve 6 becomes larger than that when the first control valve 5 is within the specified opening degree, and the flow rate increases. As a result, the pressure in the surge tank 2 is the target value of the first controller 41 (for example, 30.0).
If kg / cm ² g) rises above, the first adjusting meter 41 the upper limit of the first control valve acts on the side of reducing the 5 opening, eventually opening the specified range of the first control valve 5 Below the specified value set below or decreased slightly, for example, the opening is 70%
Below or smaller, the first monitor switch 433
Is reset, the output of the first control valve opening determination unit 43 is turned off, and the target value of the second controller 42 becomes the same as the target value of the first controller 41, for example, 30 kg / cm ² g. Returned,
In addition, the control gain of the second controller 42 is significantly smaller than the normal value or the setting is changed to zero. Then, the opening degree of the second control valve 6 is slightly reduced by the proportional operation amount. However, since the valve operation of the second control valve 6 is controlled only by the integral operation, The second control valve 6 holds the valve opening, and the feedback control is almost stopped. As a result, the opening of the second control valve 6 is maintained on the open side (larger side) than when the opening of the first control valve 5 is outside the specified range, so that the pressure inside the surge tank 2 is increased. Will be controlled only by the first control valve 5. That is,
By making the process control by the first control valve 5 having a small valve capacity dominant over the process control by the second control valve 6 having a large valve capacity, the control accuracy when the process state quantity is minutely changed is obtained. Can be improved.

If the opening of the first control valve 5 is less than or equal to the lower limit value (for example, 10%) of the specified range, the second value is set to the second value.
The target value of the controller 42 of No. 29 is lower than the target value of the first controller 41 of, for example, 30 kg / cm ² g by about 0.5 kg / cm ² 29.
Since it is changed to 5 kg / cm ² g and the control gain (proportional gain and integration time) of the second controller 42 is changed to a normal value, the second control valve 6 and the first control valve 5 are Feedback control by proportional + integral calculation at the same time.
The target value of the controller 6 (eg, 29.5 kg / cm ² g) is the first
Since it is lower than the target value of the controller 41 (for example, 30.0 kg / cm ² g), the second control valve 6 is operated by the proportional + integral operation.
Functioning to reduce the opening of the first control valve 5
(For example, 10%) or more or more, the opening degree of the second control valve 6 becomes smaller, the flow rate increases, and the pressure in the surge tank 2 decreases. The pressure inside the surge tank 2 is the first
When it falls below a target value of the controller 41 (for example, 30.0 kg / cm ² g), the first controller 41 functions to increase the opening degree of the first control valve 5, and eventually the first controller 41 is opened. The opening degree of the control valve 5 is increased so that the opening degree of the first control valve 5 is, for example, 30%.
When it is equal to or more than the above value, the first control valve opening determination unit 43 is reset and the target value of the second controller 42 is set to the first controller 4
The same as the target value of 1, for example, 30 kg / cm ² g, and the proportional gain of the second controller 42 is significantly smaller than the normal value or is changed to zero. However, since the opening / closing operation of the second control valve 6 is controlled only by the integral operation, the second control valve 6 keeps the valve opening. The feedback control is almost stopped. As a result, the opening degree of the second control valve 6 is maintained on the closed side (smaller side) than the state before the opening degree of the first control valve 5 is equal to or less than the specified value or becomes smaller. The pressure inside the tank 2 is controlled only by the first control valve 5. This makes it possible to control the internal pressure of the surge tank 2 stably.

Next, a fourth embodiment of the present invention will be described.

FIG. 8 shows a fourth embodiment of the process control device of the present invention.
3 is a control block diagram of the embodiment of FIG. FIG. 9 shows a detailed control block diagram of the first control valve opening determination unit of the fourth embodiment of the process control device of the present invention. 8 and 9
22 is a fuel gas pressure transmitter for detecting and transmitting the fuel gas pressure on the upstream side of the first control valve 5 and the second control valve 6,
44 is a first control valve opening determination unit that outputs a signal based on the output signal from the fuel gas pressure transmitter 22, 441 is an input terminal, and 443 is a first signal that outputs a predetermined signal based on the input signal. Monitor switch, 444 is output terminal, 44
5 is a second signal generator for outputting a signal having a preset value, 446 is a second monitor switch for outputting a predetermined signal based on the input signal, 447 is an output terminal, 448 is an input terminal, and 44a is First control valve 5 and second control valve 6
2 shows a pressure compensating unit for performing a function operation on the fuel gas pressure on the upstream side of and to output.

The fourth embodiment is an example in which a first control valve opening determination section 44 is installed in place of the first control valve opening determination section 43 of the first embodiment. . That is, the first
In this example, the target value of the second control valve 6 is changed based on the fuel gas pressure on the upstream side of the control valve 5 and the second control valve 6.

When the pressure inside the fuel gas supply header 1 rises and the inlet (upstream side) pressures of the first control valve 5 and the second control valve 6 rise, the density rises as the pressure rises.
Even if the opening degree of the first control valve 5 is within the specified range, the flow rate passing through the first control valve 5 increases. Therefore, the fuel gas pressure transmitter 22 is installed on the upstream side of the first control valve 5 and the second control valve 6, and the inlet pressures of the first control valve 5 and the second control valve 6 are detected, It is transmitted to the pressure compensator 44a via the input terminal 448. Then, in the pressure compensating unit 44a, the inlet pressure detection signals of the first control valve 5 and the second control valve 6 are functionally calculated so as to match the fuel gas density accompanying the pressure change of the fuel gas, and the output signal thereof is calculated. The first monitor switch 4 is transmitted to the first monitor switch 4
By decreasing the set value of 43, the target value of the second controller 42 is changed to a high value before the flow rate of the first control valve 5 becomes excessive.

According to the fourth embodiment, even when the fuel gas pressure is high, the operation is not performed at an excessive flow rate, so that the first control valve 5 can be prevented from generating excessive vibration or noise. Get the effect you can. Furthermore, the first control valve 5
The effect of suppressing control interference with the second control valve 6 is obtained. Furthermore, an effect of suppressing control interference between the first control valve 5 and the second control valve 6 is obtained.

Next explained is the fifth embodiment of the invention.

FIG. 10 shows a control block diagram of the fifth embodiment of the process control apparatus of the present invention. FIG. 11 shows a detailed control block diagram of the first control valve opening determination unit of the fifth embodiment of the process control device of the present invention. Figure 1
0, in FIG. 11, 23 is a fuel gas temperature transmitter for detecting and transmitting the fuel gas temperature on the upstream side of the first control valve 5 and the second control valve 6, and 45 is an output from the fuel gas pressure transmitter 22. A first control valve opening determination unit that outputs a signal based on the signal or / and the output signal from the fuel gas temperature transmitter 23, 45
1 is an input terminal, 453 is a first monitor switch that outputs a predetermined signal based on the input signal, 454 is an output terminal, 455 is a second signal generator that outputs a signal of a preset value, and 456 is A second monitor switch that outputs a predetermined signal based on an input signal, 457 is an output terminal,
Reference numeral 458 is an input terminal, 459 is an input terminal, 45a is a pressure compensating portion for performing a function operation on the fuel gas pressures on the upstream side of the first control valve 5 and the second control valve 6, and outputting the same, and 45b is a first control valve. 5 and a temperature compensating unit that outputs the fuel gas temperature on the upstream side of the second control valve 6 by performing a function operation, and 45c indicates a multiplying unit that multiplies the input signal and outputs it.

The present fifth embodiment is an example in which a first control valve opening determination unit 45 is installed in place of the first control valve opening determination unit 43 of the first embodiment. . That is, the first
Second control valve 6 based on the fuel gas pressure upstream of the control valve 5 and the second control valve 6 and / or the fuel gas temperature upstream of the first control valve 5 and the second control valve 6. This is an example of changing the target value of.

When the internal pressure of the fuel gas supply header 1 rises and the inlet temperatures of the first control valve 5 and the second control valve 6 decrease, the density increases as the temperature decreases, so the first control valve Even if the opening degree of 5 is within the specified range, the flow rate passing through the first control valve increases. Therefore, the fuel gas pressure transmitter 22 is installed on the upstream side of the first control valve 5 and the second control valve 6, and the inlet pressure of the first control valve 5 and the second control valve 6 is detected and input. It is transmitted to the pressure compensator 45a via the terminal 458. On the other hand, the fuel gas temperature transmitter 23 is installed on the upstream side of the first control valve 5 and the second control valve 6, and the inlet temperature of the first control valve 5 and the second control valve 6 is detected and input. It is transmitted to the temperature compensation unit 45b via the terminal 459. still,
As for the positional relationship between the fuel gas pressure transmitter 22 and the fuel gas temperature transmitter 23, any of them may be located on the upstream side. Then, in the pressure compensator 45a, the inlet pressure detection signals of the first control valve 5 and the second control valve 6 are functionally calculated so as to match the density of the fuel gas accompanying the change in the pressure of the fuel gas, and the output signal thereof is output. Is transmitted to the multiplication unit 45c. Temperature compensator 45
In b, the inlet temperature detection signals of the first control valve 5 and the second control valve 6 are functionally calculated so as to match the density of the fuel gas accompanying the temperature change of the fuel gas, and the output signal is supplied to the multiplication unit 45c. introduce. In the temperature compensation unit 45b, the inlet temperature detection signals of the first control valve 5 and the second control valve 6 are functionally calculated so as to match the density of the fuel gas accompanying the temperature change of the fuel gas, and the output signal is multiplied. It is transmitted to the portion 45c.
When the inlet temperatures of the first control valve 5 and the second control valve 6 decrease, the temperature compensating unit 45b decreases the set value of the first monitor switch 453,
The target value of the second controller 42 is changed to a higher value.

According to the present fifth embodiment, even if the fuel gas temperature is low, the first control valve 5 is prevented from generating excessive vibration or noise because it is not operated at an excessive flow velocity. Get the effect you can. Furthermore, the first control valve 5
The effect of suppressing control interference with the second control valve 6 is obtained. Furthermore, an effect of suppressing control interference between the first control valve 5 and the second control valve 6 is obtained.

Next, a sixth embodiment of the present invention will be described.

FIG. 12 shows a control block diagram of the sixth embodiment of the process control apparatus of the present invention. FIG. 13 shows each state quantity (load flow rate, first control valve, second control valve supply flow rate, surge tank internal pressure, target set pressure, first flow rate) according to the sixth embodiment of the process control device of the present invention. 2 is a time chart comparing the control valve opening degree of No. 2 and the second control valve opening degree of No. In FIG. 12 and FIG. 13, 3 is a fuel gas flow rate transmitter for detecting and transmitting the fuel gas flow rate on the downstream side of the surge tank 2,
Reference numeral 423 is a preceding control calculation unit that performs advance control of the second control valve 6 based on the fuel gas flow rate, 423a is an addition / subtraction calculation unit that outputs by adding or subtracting an input signal, and 423b is a second control unit based on the fuel gas flow rate. The pressure precedence control calculation part which carries out precedence control of the control valve 6 is shown.

The sixth embodiment is an example in which the second control valve 2 is controlled in advance on the basis of the fuel gas flow rate on the downstream side of the surge tank 2 in comparison with the first embodiment.

A flow rate transmitter 3 for detecting and transmitting the flow rate of the fuel gas is installed on the downstream side of the surge tank 2, the outlet fuel gas flow rate of the surge tank 2 is detected, and the pressure precedent control calculating section is provided.
Transmit to 423b. The pressure precedent control calculation unit 423b performs a function calculation of the outlet flow rate detection signal of the surge tank 2 in proportion to the outlet fuel gas flow rate, outputs the calculation result, and transmits it to the addition / subtraction calculation unit 423a. Addition / subtraction calculation unit 423
In a, the output signal from the second control calculation unit and the output signal from the pressure preceding control calculation unit 423b are added, and the result is transmitted to the second control valve 6 as the second opening command signal.
As a result, since the first control valve 5 is almost always within the specified range, the pressure in the surge tank 2 can be controlled more stably than in the first embodiment of the present invention as shown in FIG. become.

Next, a seventh embodiment of the present invention will be described.

FIG. 14 shows a control block diagram of the seventh embodiment of the process control apparatus of the present invention. In FIG. 14, 1
1 is a condenser for condensing steam discharged from the steam turbine, 12 is a low-pressure condensate pump for boosting the condensate from the condenser 11, 13 is a high-pressure condensate for boosting the condensate from the gland condenser Pump, 14 is a deaerator that separates dissolved oxygen in the condensate to deaerate the condensate, 16 is condensate from the deaerator (water supply)
Main water pump for boosting
18 is a condensate purifier that separates impurities in the condensate to purify the condensate, 31 is a deaerator water level transmitter that detects and transmits the water level in the deaerator, and 33 is boosted by a condensate pump Condensate flow rate transmitter for detecting and transmitting the flow rate of condensate, 34 is a main water flow rate transmitter for detecting and transmitting the flow rate of feed water boosted by the water feed pump, 424 is based on the condensate flow rate and / or the feed water flow rate An advance control calculation unit 424a that controls the second control valve 6 in advance.
Is an addition / subtraction calculation unit for adding or subtracting an input signal, 424b is an addition / subtraction calculation unit for adding or subtracting an input signal, 424c is a second water level preceding control calculation unit for performing advance control of the second control valve 6 based on the water supply flow rate. Reference numeral 424d denotes a first water level advanced control calculation unit that performs advanced control of the second control valve 6 based on the condensate flow rate.

The seventh embodiment shows an example in which the process control device of the present invention is applied to the water level control in the deaerator of a thermal power and nuclear power plant.

The condensate stored in the condenser 11 is pumped out and boosted by the low-pressure condensate pump 12, and the condensate purifier 18
Water is then sent to the high-pressure condensate pump 13 via the ground condenser 17. Then, the deaerator 14 is further pressurized by the high-pressure condensate pump 13 and passes through the condensate flow rate transmitter 33 provided on the outlet side of the first regulating valve 5 and the second regulating valve 6 arranged in parallel. Sent to. Condensed water in the deaerator 14 is pumped out, boosted in pressure by the main feed water pump 16, and sent to the boiler (not shown) via the main feed water flow rate transmitter 34.

The controller 40 controls the water level in the deaerator 14 by cooperatively controlling the first control valve 5 and the second control valve 6 based on the water level in the deaerator 14. That is, the water level transmitter 31 in the deaerator is installed in the deaerator 14, and the water level in the deaerator 14 is detected and transmitted to each of the first controller 41 and the second controller 42. In the first controller 41 and the second controller 42, the water level detection signal is a target value (first target water level signal set by the first target process state quantity setting unit 412,
The first control valve 5 and the second control valve 6 are controlled so as to correspond to the second target water level signal set by the second target process state quantity setting unit 422.

The first controller 41 comprises a first target process state quantity setting unit 412 and a first control calculation unit 411. Addition / subtraction calculation unit 411 of the first control calculation unit 411
In a, the water level detection signal in the deaerator 14 detected by the water level transmitter 31 is subtracted from the first target water level signal set by the first target process state quantity setting unit 412 to calculate the proportional-plus-integral calculation unit 411b. Communicate to. Proportional-plus-integral calculation unit 411b
In the above, the deviation signal between the target water level signal and the water level detection signal is proportionally + integrated and transmitted to the first control valve 5 as a first opening command signal, and at the same time, the first control valve opening determination unit 43
Communicate to.

The second controller 42 comprises a second target process state quantity setting unit 422 and a second control calculation unit 421. In the addition / subtraction calculation unit 421a, the water level detection signal is subtracted from the second target water level signal output from the second target process state quantity setting unit 422 to calculate the proportional-plus-integral calculation unit 421.
It is transmitted to d. In the proportional-plus-integral calculation unit 421d, the second
The deviation signal between the target water level signal and the water level detection signal is calculated by proportional + integral calculation and transmitted to the preceding control calculation unit 424.

On the other hand, the main feed water flow rate transmitter 34 is installed between (the downstream side of) the main feed water pump 16 and the boiler (upstream side thereof), and the outlet feed water flow rate is detected by the main feed water flow rate transmitter 34. The result is transmitted to the second water level preceding control calculation unit 424c.
In the second water level preceding control calculation unit 424c, a function calculation proportional to the main water supply flow rate is calculated and transmitted to the addition / subtraction calculation unit 424b. Further, a condensate flow transmitter 33 is installed between (the downstream side of) the first control valve 5 and the second control valve 6 and (the upstream side of) the deaerator 14, and the condensate flow transmitter 33 is installed. At, the outlet condensate flow rate is detected, and the first water level preceding control calculation unit 424d
Communicate to. In the first water level preceding control calculation unit 424d, a function calculation proportional to the condensate flow rate is performed, and the addition / subtraction calculation unit 4
24b. In the addition / subtraction calculation unit 424b, the first
The output signal from the water level preceding control calculating unit 424d and the output signal from the second water level preceding control calculating unit 424c are added and transmitted to the addition / subtraction calculating unit 474a. In the addition / subtraction calculation unit 474a, the output signal from the second control calculation unit 421 and the output signal from the addition / subtraction calculation unit 474a are added, and the result is transmitted to the second control valve 6 as the second opening degree instruction signal. According to the seventh embodiment, the opening of the first control valve 5 is in the vicinity of the specified range, and the opening of the second control valve 6 is mainly controlled in advance. The change in the opening degree of 6 is reduced, and the effect that stable control of the water level in the deaerator is possible is obtained.

Next, an eighth embodiment of the present invention will be described.

FIG. 15 shows a control block diagram of the eighth embodiment of the process control apparatus of the present invention. In FIG. 15, 3
Reference numeral 5 denotes a check valve that blocks the reverse flow of fluid.

The eighth embodiment of the present invention shows an example in which the process control device of the present invention is applied to condensate recirculation flow rate control used in a nuclear power plant.

The condensate whose pressure is increased by the low pressure condensate pump 12 is
After passing through the condensate purifier 18, the ground condenser 17, and the condensate flow rate transmission unit 33, the condensate is transmitted to the high-pressure condensate pump 13, and the first control valve 5 and the second control valve 5 arranged in parallel are branched.
Water is sent to the control valve 6 of the. Furthermore, high pressure condensate pump 1
The condensate water whose pressure has been increased in 3 is sent to the main water supply pump 16 via the check valve 35, and branched to be sent to the first control valve 5 and the second control valve 6. First control valve 5
And the condensate from the second control valve 6 is recirculated to the condenser 11.

The control device 40 controls so as to ensure the minimum flow rate of the condensed water sent from the condenser 11. That is, the condensate flow rate transmitter 33 is installed between the condenser 11 and the upstream branch point of the high-pressure condensate pump 13, and the condensate flow rate sent from the condenser 11 is detected. To the second controller 41 and the second controller 42. In the first controller 41 and the second controller 42, the flow rate detection signal is set to the target value (first target process state quantity setting unit 412).
Target flow rate signal, second target process state quantity setting unit 42
2nd target flow rate signal set in 2),
The first control valve 5 and the second control valve 6 are controlled.

According to the eighth embodiment, like the first embodiment, when the opening of the first control valve 5 is within the specified range, the value of the second target flow rate signal is When the first control valve 5 is out of the specified opening range, the value of the second target flow rate signal is higher (or lower) than the value of the first target flow rate signal. Is set to. As a result, the first
The opening degree of the control valve 5 is controlled in the vicinity of the specified range, and the second control valve 6 having a large capacity is less likely to be controlled by the minute opening degree. It will be possible.

Next, a ninth embodiment of the present invention will be described.

FIG. 16 shows a control block diagram of the ninth embodiment of the process control apparatus of the present invention. In FIG. 16, 6
Reference numeral 1 is a steam supply header for supplying steam, 62 is a cooling water supply header for supplying cooling water, 64 is a temperature reducer for injecting cooling water into the steam to reduce the temperature of the steam, and 72 is for detecting and transmitting the steam temperature. 3 shows a steam temperature transmitter.

The ninth embodiment of the present invention shows an example in which the process control device of the present invention is applied to steam temperature control for reducing the temperature of steam to control the temperature of steam.

A desuperheater 64 is installed midway from the steam supply header 61 to the steam consuming side header. On the other hand, the cooling water is supplied from the cooling water supply header 62 to the desuperheater 64, and the desuperheater 6
The temperature of the steam is reduced by injecting cooling water into the steam in 4. At this time, the first control valve 5 and the second control valve 6 are arranged in parallel in the cooling water system from the cooling water supply header 62 to the temperature reducer 64, and the first control valve 5 and the second control valve 5 are provided. The control valve 6 is controlled to control the flow rate of the cooling water supplied to the temperature reducer 64, to control the amount of steam temperature reduction, and to control the temperature of the steam.

The controller 40 determines whether the first control is based on the steam temperature.
The control valve 5 and the second control valve 69 are coordinatedly controlled to control the steam temperature. That is, the steam temperature transmission unit 72 is installed on the downstream side of the desuperheater 64 (upstream side of the steam consumption side header),
The first controller 41 and the second controller 4 which detect the steam temperature
2 and each transmit. In the first controller 41 and the second controller 42, the steam temperature detection signal has a target value (first
Target process state quantity setting unit 412 for setting the first target steam temperature signal and the second target process state quantity setting unit 4
The first control valve 5 and the second control valve 6 are controlled so as to meet the second target steam temperature signal set at 22).

According to the ninth embodiment, the opening degree of the first adjusting valve 5 is controlled in the vicinity of the specified range, and the second adjusting valve 6 having a large capacity is controlled with a small opening degree. Since the amount of cooling water is reduced, the change in the flow rate of cooling water is reduced, and stable steam temperature control can be achieved.

Next explained is the tenth embodiment of the invention.

FIG. 17 shows a control block diagram of the tenth embodiment of the process control device of the present invention. In FIG.
Second Embodiment of Tenth Embodiment of Process Control Apparatus of the Present Invention
3 is a detailed control block diagram of the controller compensation calculation unit of FIG. In FIGS. 17 and 18, 422b is a second target process state quantity setting unit for setting a process state quantity targeted by the second control valve 6, and 49 is a second target process state quantity setting unit based on the opening degree of the first control valve. Second controller compensating calculation unit for compensating the opening degree of the control valve of 491, 491
Is an input terminal, 492 is a preset A-side set value, 49
3 is a selection switch for selecting and outputting an input signal, 494
Is a preset B-side set value, 495 is an integration calculation unit that performs integration calculation of an input signal and outputs it, 496 is an input terminal, 497
Is a preset C-side set value, 498 is a selection switch for selecting and outputting an input signal, 499 is a preset D
A side set value, 49b is an addition / subtraction calculation unit for adding or subtracting an input signal, 49c is an output terminal, and 49d is an addition / subtraction calculation unit for adding or subtracting an input signal.

The tenth embodiment is set based on the output signal (first target pressure signal) from the first target process state quantity setting unit 412 of the third embodiment. The second target process state quantity setting unit 422 is provided with a second target process state quantity setting unit 422b which is set independently of the first target process state quantity setting unit 412.

The control device 40 controls the pressure in the surge tank 2 by cooperatively controlling the first control valve 5 and the second control valve 6 based on the pressure in the surge tank 2. That is, the surge tank pressure transmitter 21 is installed in the surge tank 2,
The pressure in the surge tank 2 is detected and transmitted to each of the first controller 41 and the second controller 42. First controller 41
In the second controller 42, the pressure detection signals are respectively set to target values (the first target pressure signal set by the first target process state quantity setting unit 412 and the second target process state quantity setting unit 422). The first control valve 5 and the second control valve 6 are controlled so as to meet the set second target pressure signal).

The first controller 41 includes an addition / subtraction calculator 411a.
At the first target process state quantity setting unit 412, the pressure detection signal transmitted from the surge tank pressure transmitter 21 is subtracted from the first target pressure signal set by the first target process state quantity setting unit 412. It is calculated and transmitted to the first control valve 5 and the first control valve opening determination unit 43 as a first opening command signal. First control valve opening determination unit 43
In, the opening degree of the first control valve 5 is determined to be outside the specified range and / or within the specified range, and a signal is output. The output signal from the first control valve opening determination unit 43 is transmitted to the second controller compensation calculation unit 49. The input terminal 491 of the second controller compensation calculation unit 49 and the output terminal 434 of the first control valve opening determination unit 43 are connected, and the input terminal 496 of the second controller compensation calculation unit 49 and the first The output terminal 437 of the control valve opening determination unit 43 is connected. The output signal from the first control valve opening determination unit 43 is input terminal 431.
Via the first monitor switch 43 with dead band
3 is transmitted to the second monitor switch 436 having a dead band.

Input terminal 4 of first control valve opening determination unit 43
When the signal of 31 is equal to or more than or exceeds the setting value of the first signal generating unit 432, the first monitor switch 433 is turned on and outputs a signal, and the signal is equal to or less than the setting value of the first signal generating unit 432 and The first monitor switch 433 is reset when the difference falls below or above the difference. The output of the first monitor switch 433 is transmitted to the output terminal 434,
It is transmitted to the selection switch 493 via the input terminal 491. When the input signal from the input terminal 491 is ON,
For example, when the A side set value 492 set to + 1% is selected and the input signal from the input terminal 491 is OFF,
The B-side set value 494 set to 0% is selected and transmitted to the addition / subtraction calculation unit 49b.

When the signal from the input terminal 431 of the first control valve opening determination unit 43 is less than or equal to the set value of the second signal generation unit 435, the second monitor switch 436 is turned on and the signal is output. , If the value rises above the set value of the second signal generator 435 and above or above the dead band,
The second monitor switch 436 is reset. Second
The output of the monitor switch 436 is transmitted to the output terminal 437 and is transmitted to the selection switch 498 via the input terminal 496. When the input signal from the input terminal 496 is ON, for example, the C-side set value 497 set to -1% is selected, and when the input signal from the input terminal 496 is OFF, D set to 0% is set. The side set value 499 is selected and transmitted to the addition / subtraction calculation unit 49b.

Then, the output signal of the addition / subtraction calculation unit 49b is
The result of the integral calculation is transmitted to the integral calculation unit 495, and the result of the integral calculation is transmitted to the output terminal 49c and becomes the output of the second controller correction calculation unit 49.

When the output of the first controller 41 is within the specified range, the output of the second controller correction calculator 49 is almost constant, so the output change of the addition / subtraction calculator 49d is The change of the output signal of the control calculation unit 421 is only, and the valve opening of the second control valve 6 hardly changes. Here, the control gain of the first controller 41 is set to be more sensitive than the control gain of the second controller 42. For example, the proportional gain is set to about 1.0 and the integration time is set to about 10 seconds. And also the second
The controller is set to be less sensitive than the first controller. For example, the proportional gain is about 0.2 and the integration time = 30.
Set to seconds. In this way, by setting the control gain of the first controller 41 and the control gain of the second controller 42, when the opening degree of the first controller valve 5 is within the specified range, surge If the pressure in tank 2 changes slightly, the second
The change in the valve opening of the control valve 6 is reduced, and the flow rate of the fuel gas is controlled by almost only the first control valve 5. Therefore, during constant plant load operation, control interference between the second control valve 6 and the first control valve 5 does not occur, and the surge tank 2
The internal pressure is controlled stably.

When the opening of the first control valve 5 is out of the specified range, the first monitor switch 433 is turned on and the input signal of the input terminal 491 is turned on. , Is transmitted to the integration calculation unit 495 via the addition / subtraction calculation unit 49b, and the integration calculation result is output to the output terminal 49.
It is transmitted to the addition / subtraction calculation unit 49d via c. As a result, it functions to increase the valve opening of the second control valve 6,
The opening degree of the second control valve 6 gradually becomes larger than that when the first control valve 5 is within the specified opening degree, the fuel gas flow rate increases, and the surge tank 2 internal pressure rises. As a result, the first
The valve opening of the control valve 5 is decreased to within the specified opening, and the control is stabilized.

When the opening degree of the first control valve 5 is within the specified range, the second monitor switch 436 is turned on and the input signal of the input terminal 496 is turned on. Therefore, the C side set value 497 is set. Is transmitted to the integration calculation unit 495 via the addition / subtraction calculation unit 49b, and the integration calculation result is output to the output terminal 49c.
Is transmitted to the addition / subtraction calculation unit 49d via.

As a result, the second control valve 6 functions to reduce the valve opening, and the second control valve 6 is opened more than when the first control valve 5 is within the specified opening. It becomes smaller, the flow rate of fuel gas decreases, and the pressure in the surge tank 2 decreases. As a result, the valve opening of the first control valve 5 is increased to be within the specified opening, the control is stabilized, and the surge tank 2 can be controlled to a stable pressure.

Next explained is the eleventh embodiment of the invention.

FIG. 19 shows a control block diagram of the eleventh embodiment of the process control apparatus of the present invention. In Figure 20,
The second of the eleventh embodiment of the process control apparatus of the present invention
3 is a detailed control block diagram of the target setting function operation part of FIG.

In FIGS. 19 and 20, 50 is the second control valve 6
Is a second target setting function operation unit for changing the target process state quantity, 501 is an input terminal, 502 is a function operation unit for converting and outputting an input signal according to a preset predetermined function, and 503 is an output terminal. Show.

The eleventh embodiment of the present invention replaces the first control valve opening determination unit 43 and the second target process state quantity adjustment unit 47 of the first embodiment of the present invention. , First
In this example, a function calculation unit 502 having the functions of the control valve opening determination unit 43 and the second target process state quantity correction unit 47 is installed.

The output signal (first opening degree command signal) from the first controller 41 is transmitted to the second target setting function computing section 50. In the second target setting function calculation unit 50, the input signal of the input terminal 501 is transmitted to the function calculation unit 502. In the function calculation unit 502, the input signal (the opening degree of the first control valve 5) is 0 or more and the lower limit value of the specified range (for example, 20
%) Or less or a small value, a signal corresponding to the input signal (e.g., -1% to 0 range) is output, and a second lower limit value (e.g., 20%) or higher of the specified range (e.g. 80%) or less or 0% signal is output,
When the value is equal to or larger than the second specified value or larger than 100%, a signal (for example, a range of 0 to 1%) corresponding to the input signal is output. Accordingly, when the opening degree of the first control valve 5 is within the specified range, the output of the second target setting function calculation unit 50 becomes 0%, so that the target value of the second controller 42 and the The target value of the controller 41 of No. 1 is the same (30.0 kg / cm ² g). The control gain of the first controller 41 is more sensitive than the control gain of the second controller 42, for example, the proportional gain is about 1.0,
The integration time is set to about 10 seconds, and the control gain of the second controller 42 is less sensitive than the control gain of the first controller 41.
For example, by setting the proportional gain = about 0.2 and the integration time = about 30 seconds, the opening of the first control valve 5 is within the specified range, and the pressure inside the surge tank 2 changes slightly. In addition, the change in the opening degree of the second control valve 6 is reduced,
It is controlled only by the control valve 5 of. Therefore, the control interference between the second control valve 6 and the first control valve 5 does not occur while the plant load is constant.

When the opening degree of the first control valve 5 is equal to or larger than the upper limit value of the specified range or is large, the output of the second target setting function calculation unit 50 becomes + 1% to 0%, and the addition / subtraction calculation unit 422a
A signal of + 1% to 0% is transmitted. As a result, since the target value of the second controller 42 is changed to + 1% to 0% higher than the target value of the first controller 41 (for example, 30 kg / cm ² g), proportional + integral The operation functions to increase the opening degree of the second control valve 6, and the opening degree of the second control valve 6 becomes gradually larger than when the first control valve 5 is within the specified opening degree. Since the flow rate increases, the pressure inside the surge tank 2 increases. As a result, the opening degree of the first control valve 5 decreases to fall within the specified opening degree, and the control becomes stable.

When the opening degree of the first control valve 5 is less than or equal to the lower limit value of the specified range or is small, the output of the second target setting function calculation unit 50 becomes -1% to 0%, and the addition / subtraction calculation unit 422a.
A signal of -1% to 0% is transmitted to. Second controller 42
Is the target value of the first controller 41 (for example, 30
kg / cm ² g), the setting is changed to 1% to 0% lower,
The second control valve 6 functions to reduce the valve opening of the second control valve 6 by the proportional + integral operation, and the opening of the second control valve 6 is smaller than when the first control valve 5 is within the specified opening. As a result, the fuel gas flow rate decreases, so the pressure in the surge tank 2 decreases.
As a result, the opening of the first control valve 5 is increased to be within the specified opening, and the control is stabilized. As a result, the surge tank 2 can be controlled to a stable pressure.

[0104]

According to the present invention, the target value of the process state quantity of the second control valve (large control valve) is set according to the valve opening of the first control valve (small control valve). The effect of suppressing the control interference between the first control valve and the second control valve is obtained by changing

That is, when the valve opening degree of the first control valve is large, the value of the process state quantity of the first control valve is larger than the target value.
The target value of the process state quantity of the second control valve is increased.
As a result, when the detected value of the process state quantity exceeds the target value of the process state quantity of the first control valve, the first control valve is conversely controlled in the closing direction. Then, when the valve opening of the first control valve becomes smaller, the target value of the process state quantity of the second control valve is made smaller. When the valve opening degree of the first control valve is small, the target value of the process state quantity of the second control valve is made smaller than the target value of the process state quantity of the first control valve. As a result, when the detected value of the process state quantity becomes smaller than the target value of the process state quantity of the first control valve, the first control valve is conversely controlled to open. Then, when the valve opening degree of the first control valve increases, the target value of the process state quantity of the second control valve is increased.

[Brief description of drawings]

FIG. 1 is a control block diagram of a first embodiment of a process control device of the present invention.

FIG. 2 is a detailed control block diagram of a first control valve opening determination unit according to the first embodiment of the process control device of the present invention.

FIG. 3 is a detailed control block diagram of a second target process state quantity compensating unit of the first embodiment of the process control apparatus of the present invention.

FIG. 4 is a time chart comparing state quantities according to the first embodiment of the process control apparatus of the present invention.

FIG. 5 is a control block diagram of a second embodiment of the process control device of the present invention.

FIG. 6 is a control block diagram of a third embodiment of a process control device of the present invention.

FIG. 7 is a detailed control block diagram of a control arithmetic unit with a second control gain compensation of the third embodiment of the process control device of the invention.

FIG. 8 is a control block diagram of a fourth embodiment of the process control device of the present invention.

FIG. 9 is a detailed control block diagram of a first control valve opening determination unit according to the fourth embodiment of the process control device of the present invention.

FIG. 10 is a control block diagram of a fifth embodiment of the process control device of the present invention.

FIG. 11 is a detailed control block diagram of a first control valve opening determination unit according to the fifth embodiment of the process control device of the present invention.

FIG. 12 is a control block diagram of a sixth embodiment of the process control device of the present invention.

FIG. 13 is a time chart comparing state quantities according to the sixth embodiment of the process control apparatus of the present invention.

FIG. 14 is a control block diagram of a seventh embodiment of the process control device of the present invention.

FIG. 15 is a control block diagram of an eighth embodiment of the process control device of the present invention.

FIG. 16 is a control block diagram of a ninth embodiment of the process control device of the present invention.

FIG. 17 is a control block diagram of a tenth embodiment of the process control device of the present invention.

FIG. 18 is a detailed control block diagram of a second controller compensation calculation unit of the tenth embodiment of the process control device of the present invention.

FIG. 19 is a control block diagram of an eleventh embodiment of a process control device of the present invention.

FIG. 20 is a detailed control block diagram of a second target setting function calculation unit of the eleventh embodiment of the process control device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel gas supply header, 2 ... Surge tank, 3 ... Fuel gas flow transmitter, 5 ... 1st control valve, 6 ... 2nd control valve, 7 ... 1st control valve opening transmitter, 11 ... Condenser, 12
... low pressure condensate pump, 13 ... high pressure condensate pump, 14 ... deaerator, 16 ... main feed pump, 17 ... ground condenser,
18 ... Condensate purifier, 21 ... Surge tank pressure transmitter,
22 ... Fuel gas pressure transmitter, 23 ... Fuel gas temperature transmitter, 31 ... Deaerator internal water level transmitter, 33 ... Condensate flow rate transmitter, 34 ... Main feed water flow rate transmitter, 35 ... Check valve, 40 ... Control device, 41 ... First controller, 42 ... Second controller, 4
3, 45 ... 1st control valve opening determination part, 44 ... 1st control valve opening determination part, 44a, 45a ... Pressure compensation part, 45b ...
Temperature compensator, 45c ... Multiplier, 47 ... Second target process state quantity compensator, 47a, 48b, 475, 487 ... First-order lag calculator, 47b, 49b, 49d, 411a, 4
21a, 422a, 423a, 424a, 424b ... Addition / subtraction calculation unit, 47c, 48e, 49c, 434, 437, 44
4, 447, 454, 457, 503 ... Output terminals, 48 ... Second control gain-compensated control calculation section, 48a ... Second integration time setting section, 48c, 431, 441, 448, 45
1,458,459,471,476,481,48
2, 491, 496, 501 ... Input terminals, 48d, 41
1b, 42d ... Proportional / integral calculation unit, 49 ... Second controller compensation calculation unit 50 ... Second target setting function calculation unit, 61 ... Steam supply header, 62 ... Cooling water supply header, 64 ... Desuperheater,
72 ... Steam temperature transmitter, 411 ... 1st control calculation part, 41
2 ... 1st target process state amount setting part, 421 ... 2nd control calculation part, 422, 422b ... 2nd target process state amount setting part, 423, 424 ... Advance control calculation part, 423b ... Pressure advance control calculation Unit, 424c ... Second water level preceding control calculating unit, 424d ... First water level preceding control calculating unit, 432 ... First signal generating unit, 433, 443, 453 ... First monitor switch, 435, 445, 455 ... second signal generator, 436,446,456 ... second monitor switch, 472,492 ... A side set value, 473,478,48
5,489,493,498 ... Selection switch, 474
494 ... B side set value, 477, 497 ... C side set value, 4
79, 499 ... D side set value, 483 ... Logical sum, 484 ...
1st proportional gain setting part, 486 ... 2nd proportional gain setting part, 488 ... 1st integration time setting part, 495 ... Integral operation part, 502 ... Function operation part.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-82303 (JP, A) JP-A-61-180809 (JP, A) JP-A-52-64502 (JP, A) JP-A-59- 87503 (JP, A) JP-A-8-152919 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G05B 11/36 G05B 13/02 G05D 7/06 F01D 17/24 F01K 13/02 F02C 9/00

Claims (7)

(57) [Claims] 1. A large-capacity control valve and a small-capacity control valve, which are arranged in parallel with each other, are controlled so that the process state quantity corresponds to a preset target value of the process state quantity.
In the process control method for controlling the process state quantity, when said small volume of the regulating valve exceeds a or the first predetermined valve opening time reaches the first predetermined opening degree or more, which is set in advance In addition, the target value of the process state quantity of the large capacity control valve is increased, and the small capacity control valve is equal to or less than a second predetermined valve opening degree set to be equal to or less than the first predetermined valve opening degree. or the time was the
A process control method, wherein a target value of the process state quantity of the large capacity control valve is reduced when the valve opening is smaller than a second predetermined valve opening . 2. A large-capacity control valve and a small-capacity control valve, which are arranged in parallel with each other, are controlled so that the process state quantity corresponds to a preset target value of the process state quantity,
In the process control method for controlling the process state quantity, when the small-capacity control valve is equal to or smaller than a preset first predetermined valve opening or smaller than the first predetermined valve opening. At that time, the target value of the process state quantity of the large-capacity control valve is reduced, and the small-capacity control valve is set to the second predetermined valve opening degree equal to or larger than the first predetermined valve opening degree. or when the became more valve opening
A process control method comprising increasing a target value of the process state quantity of the large capacity control valve when a second predetermined valve opening is exceeded. 3. A large-capacity control valve and a small-capacity control valve, which are arranged in parallel with each other, are controlled so that the process state quantity corresponds to a preset target value of the process state quantity.
In the process control method for controlling the process state quantity, when the small capacity control valve is out of a preset first predetermined valve opening range, the process state quantity of the large capacity control valve When the target value is changed and the small capacity control valve is within the second predetermined opening range set within the first predetermined valve opening range, the process of the large capacity control valve is performed. A process control method characterized by returning a target value of a state quantity to an original value. 4. The control gain of a controller for controlling the large capacity control valve is increased when the small capacity control valve is out of the first predetermined opening range. Item 4. The process control method according to Item 3. 5. The control gain of a controller for controlling the large capacity control valve is reduced when the small capacity control valve is within the second predetermined opening range. Item 4. The process control method according to Item 3. 6. A first control valve and a second control valve which are arranged in parallel with each other, and a transmitter which detects a process state quantity.
A setting unit that sets a target value of the process state quantity; and a first control valve that controls the first control valve based on a detected value of the process state quantity detected by the transmitter and a target value of the process state quantity. 1 based on the detected value of the process state quantity and the target value of the process state quantity.
A second controller for controlling the control valve of the second controller, a target for changing a target value of the process state quantity of the second controller according to an opening degree of the first controller valve. A process control device having a process state quantity changing unit. 7. A surge tank for storing a fuel gas to be supplied to a gas turbine combustor, and a first control valve and a second control valve arranged in parallel to each other in a flow path of the fuel gas to be supplied to the surge tank. A pressure transmitter for detecting the pressure in the surge tank, a target pressure setting unit for setting a target value of the pressure in the surge tank, and detection of the pressure in the surge tank detected by the pressure transmitter. A first controller for controlling the first control valve based on a value and a target value of pressure in the surge tank, a detected value of pressure in the surge tank, and a target value of pressure in the surge tank And a second controller for controlling the second controller on the basis of the above-mentioned, in a surge tank pressure control device, the second controller of the second controller according to the opening degree of the first controller valve. Target of pressure in surge tank A surge tank pressure control device having a target pressure changing unit for changing a value.