JPH11272302A - Process control device and its controlling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress control interference between a 1st control valve (small capacity control valve) and a 2nd control valve (large capacity control valve) by changing an objective value for the process state quantum of the 2nd control valve in accordance with the valve aperture of the 1st control valve. SOLUTION: In the process control method, a process state quantum is controlled by controlling the large capacity control valve 6 and the small capacity control valve 5 arranged in parallel with each other so that the process state quantum of the valve 6 corresponds to a previously set objective value. When the control valve 5 exceeds a 1st prescribed valve aperture range which has been previously set up, the objective value of the process state quantum of the control valve 6 is changed, and when the valve 5 is entered into a 2nd prescribed aperture range set up in the 1st prescribed valve aperture range, the objective value of the process state quantum of the valve 6 is restored to the original objective value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for controlling state (e.g., pressure, water level, flow rate, temperature, etc.) of a process by controlling a first control valve and a second control valve arranged in parallel with each other. , Which is referred to as a “process state quantity”) and a control method thereof, and particularly relates to a main steam, an auxiliary steam, a combustion gas, an exhaust gas, a fuel, a condensate, and the like of a thermal power plant or a nuclear power plant. The present invention relates to a process control device that controls a process state quantity such as water supply and water storage, and a control method thereof.

[0002]

2. Description of the Related Art In the 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 actively opened and closed, and when the change width of the process state quantity is large, the large capacity valve is actively opened and closed. .

For example, Japanese Patent Laid-Open Publication No. Sho 56-82303 discloses that a second control valve (large capacity) performs feedforward control based on a temperature difference between a high temperature side and a low temperature side in a steam generator. When the control valve (small capacity) performs feedback control by the three elements of the water level of the closed container, the steam flow rate, and the feed water flow rate, and when the opening degree of the first control valve becomes equal to or more than a set opening degree,
The second control valve is forcibly opened, and when the first control valve becomes smaller than a predetermined opening, the second control valve is forcibly opened.
A water level control device for generating a signal for closing a control valve of the first function generator and adding the signal to an output signal of a first function generator to control a second control valve is described.

Japanese Patent Application Laid-Open No. 61-180809 discloses that a deviation between a detected water level signal and a water level set value is proportionally / integrally operated to control a first control valve (small capacity). The second control valve (large capacity) is controlled by proportionally and integrating the deviation between the opening signal transmitted to the first control valve and the opening set value, thereby opening the first control valve. A water level control device that controls an opening degree of a second control valve so as to be a degree setting value is described.

Japanese Patent Application Laid-Open No. 52-64502 discloses that a small valve (small capacity) is used at the time of starting and stopping a plant, and the small valve is closed and a main valve (large capacity) is opened as the load increases. Accordingly, a deaerator level control device that controls a deaerator level by switching from a child valve to a parent valve is described.

Japanese Patent Application Laid-Open No. 59-87503 discloses that a large-capacity control valve and a small-capacity control valve are controlled by a common controller (split range control), and the output value of the controller is set to a first signal level. Describes a process control device that increases the control gain of the large-capacity control valve when the pressure reaches the control signal, and returns the control gain of the large-capacity control valve when the output value of the controller returns to the second signal level.

[0007]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. Sho 56-82303
When the opening of the first control valve is equal to or larger than a set opening as in the invention described in Japanese Patent Application Laid-Open Publication No. H10-260, the second control valve is forcibly opened by the second function generator. However, the amount of the 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 opening degree of the first control valve is adjusted to decrease by feedback control of the first control valve. Then, when the opening of the first control valve falls below a certain set opening value, the second control valve is forcibly closed by the second function generator, and the process amount sharply decreases, and the steam is reduced. Generator water level falls below the target set water level. When the process amount sharply decreases and the water level of the steam generator falls below the target set water level, the opening degree of the first control valve is adjusted to increase again by the feedback control of the first control valve. As described above, especially when the variation 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 Japanese Patent Application Laid-Open No. 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. If the required flow rate, pressure, temperature, etc. of the plant changes even in minute amounts, the opening of the first control valve changes, and accordingly, the opening of the first control valve deviates from the set opening. Accordingly, 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 and the set opening degree, which is the reference signal of the control valve, becomes larger, and the change width of the second control valve becomes larger. That is, even during a constant operation (for example, rated operation) of the plant under a high load, the first control valve continues the feedback control, and the second control valve periodically increases or decreases the opening. And even if the increase / decrease range of the second opening is the minimum, the valve opening changes stepwise by the dead zone of the second control valve,
There is a problem that the range of change of the process becomes large and the state of the process is not stable.

Further, Japanese Patent Application Laid-Open Nos. Sho 52-64502 and
Similarly, in the invention described in JP-A-59-87503,
Even when the plant is in constant operation under high load, the valve opening changes stepwise by the dead zone of the large-capacity valve, causing a problem that the process variation width becomes large 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-capacity control valve) in accordance with the opening degree of the first control valve (small-capacity control valve). Accordingly, it is an object of the present invention to provide a process control device that suppresses control interference between a first control valve and a second control valve, and a control method thereof.

[0011]

In order to achieve the above object, a process control method according to the present invention is arranged in parallel with each other so that a process state quantity matches 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 exceeds or exceeds a preset first predetermined valve opening degree, the target value of the process state quantity of the large-capacity control valve is increased, The target value of the process state quantity of the large-capacity control valve is reduced when the control valve is equal to or smaller than a second predetermined valve opening set to be equal to or smaller than the first predetermined valve opening. .

[0012] Alternatively, in order to achieve the above object, a process control method according to the present invention provides a process control method according to the present invention, wherein large-capacity large-capacity components arranged in parallel with each other so that a process status variable meets a preset target value of the process status variable. 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, the target value of the process state quantity of the large-capacity control valve is reduced, and the small-capacity control is performed. When the valve exceeds or exceeds a second predetermined valve opening set to be equal to or larger than the first predetermined valve opening, the target value of the process state quantity of the large-capacity control valve is increased.

Alternatively, in order to achieve the above object, a process control method according to the present invention provides a process control method according to the present invention, wherein a large amount of large-capacity components arranged in parallel with each other so that a process state quantity matches 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 a preset first predetermined valve opening range, the target value of the process state quantity of the large-capacity control valve is changed, When the control valve comes within a 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 a controller that controls the large-capacity control valve is increased. Preferably, when the small-capacity control valve falls within the second predetermined opening range, the control gain of a controller that controls the large-capacity control valve is reduced.

[0014] Alternatively, in order to achieve the above object, a process control device according to the present invention comprises a large-capacity large-capacity parallel-arranged mutually so that a process state quantity matches 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, the target value of the process state quantity of the large-capacity control valve when the small-capacity control valve is out of the preset predetermined valve opening range is that the small-capacity control valve has the predetermined valve opening degree. A larger value than the target value of the process state quantity of the large-capacity control valve when it is within the degree range.

Alternatively, in order to achieve the above object, a process control device according to 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 control unit that controls the first control valve based on the detected value of the process state quantity detected by the transmitter and the target value of the process state quantity. 1 controller, a second controller that controls the second control valve based on the detected value of the process state quantity and a target value of the process state quantity, and an opening degree of the first control valve. And a target process state quantity changing unit that changes a target value of the process state quantity of the second controller according to

[0016]

Embodiments of the present invention will be described below.

The first control valve having a relatively large capacity and the first control valve having a relatively small capacity arranged in parallel with each other cooperate with each other to control a process state quantity. Both the control valve and the second control valve adopt feedback control of performing integral + proportional calculation based on the detected process state quantity, and the control gain of the second controller is made larger than the control gain of the first controller. Set smaller.

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

When the control gain of the second controller that controls the second control valve is set to be extremely small as compared with the control gain of the first controller that controls the first control valve, the second control valve The sensitivity of the feedback control becomes dull, and the opening degree of the second control valve does not change much, and the process state quantity is controlled almost only by the first control valve. That is, when the process state quantity changes minutely, 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 quantity is large, the opening degree of the first control valve is set to the first specified range (for example, 10% to 90%).
%), The target value of the second control valve is changed as described above, the deviation between the target value of the second control valve and the detected value increases, and the second control valve having a relatively large capacity is provided. Is controlled to increase (or decrease) the opening degree. As a result, the process state quantity greatly changes, and conversely, the opening of the first control valve is controlled in the closing direction (or the opening direction), and the opening of the first control valve eventually falls within the second specified range. At the same time, the target value of the second control valve is also restored, and the feedback control of the second control valve becomes slow. Thereafter, the first control valve performs fine adjustment, and the process state quantity is stabilized.
Thus, control interference between the first control valve and the second control valve can be suppressed, and the process state quantity can be quickly controlled to the target value. In addition, no matter what the load flow rate is, when the process state quantity changes minutely, the process state quantity can be finely adjusted by controlling the control of the first control valve having a relatively small capacity, When the process state quantity greatly changes, the process state quantity is roughly adjusted by controlling the relatively large capacity second control valve in addition to the control of the relatively small capacity first control valve. Can be
In other words, it is possible to quickly and stably control the process state quantity to its target value irrespective of the variation in the load flow rate or the process state quantity.

Preferably, the control gain of the second controller for controlling the second control valve is changed in accordance with the change of the target value of the second control valve. That is, when the opening degree of the first control valve is within the first specified range, the control gain is compared with the control gain of the second controller when the opening degree of the first control valve is out of the first specified range. Then, the control gain of the second controller is minimized or zero. That is, when the opening of the first control valve is out of the first specified range, the control gain of the second controller is increased. Then, 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 reduced to a minimum or zero again. Thereby, the first
When the second control valve 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.

Further, preferably, the opening degree of the second control valve is calculated based on the signal corresponding to the load flow rate, and the second control valve is preliminarily controlled, whereby the process state quantity can be more quickly set to its target value. It becomes possible to control.

Hereinafter, a first embodiment of the present invention will be described.

FIG. 1 shows a first example of the process control device of the present invention.
FIG. 3 is a control block diagram of the embodiment. FIG. 2 shows a detailed control block diagram of the first control valve opening degree 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 device of the present invention. FIG. 4 shows the state quantities (load flow rate, first control valve, second control valve supply flow rate, surge tank pressure, target set pressure, and the like) according to the first embodiment of the process control device of the present invention.
4 is a time chart comparing the first control valve opening degree and the second control valve opening degree). 1 to 4, reference numeral 1 denotes a fuel gas supply header for supplying a fuel gas, 2 denotes a surge tank, 5 denotes a first control valve (small capacity valve) for adjusting a process amount, and 6 denotes a first control valve for adjusting a process amount. 2 is a control valve (large capacity valve), 21 is a pressure transmitter in the surge tank for detecting and transmitting 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 controls a degree of opening of the first control valve (calculates an opening degree command signal to the first control valve), and 411 controls a degree of opening of the first control valve. Control operation unit for calculating the opening command signal of
1a is an addition / subtraction operation unit that adds or subtracts an input signal and outputs the result. 411b is a proportional-plus-integration operation unit that outputs the input signal after performing a proportional + integral operation. 412 sets a process state quantity targeted by the first control valve. A first target process state quantity setting unit 42 controls a second control valve (calculates an opening command signal to the second control valve), and a reference numeral 421 denotes a second controller.
421a is an addition / subtraction operation unit that adds or subtracts an input signal and outputs the result, and 421b is a proportional-integral operation that calculates and outputs a proportional + integral operation of the input signal. The operation unit 422 is a second target process state amount setting unit that sets a process state amount targeted by the second control valve 6, the addition unit 422 a is an addition / subtraction operation unit that adds and subtracts an input signal and is output, and the reference numeral 43 is a unit The first for judging that the valve opening degree of the first control valve is within the specified range and / or is out of the specified range
43, an input terminal; 432, a first signal generator for outputting a signal of a preset value;
3 is a first monitor switch that outputs a predetermined signal based on an input signal, 434 is an output terminal, 435 is a second signal generator that outputs a signal of a preset value, and 436 is a signal based on the input signal. A second monitor switch for outputting a predetermined signal, 437 is an output terminal, 47 is a second target process state quantity compensating section for changing a process state quantity targeted by the second control valve, and 47a is a first order delay calculating section. , 47b are addition / subtraction operation units for adding or subtracting input signals and outputting the same, 47c is an output terminal, 471 is an input terminal, 472 is a preset A-side set value, and 473 is a selection switch for selecting and outputting an input signal. , 474 are preset B-side set values, 475
Denotes a first-order delay calculating unit, 476 denotes an input terminal, 477 denotes a preset C-side set value, 478 denotes a selection switch for selecting and outputting an input signal, and 479 denotes a preset D-side set value.

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

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

Incidentally, the valve capacity of the first control valve 5 (small capacity valve) ≦ the valve capacity of the second control valve 6 (large capacity valve). More 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 degree 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 operation unit 411 includes an addition / subtraction operation unit 411a and a proportional-integral operation 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 operation unit 421 includes an addition / subtraction operation unit 421a
And a proportional-integral operation unit 421d.

In the first target process state quantity setting section 412, a 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 Set g). In the addition / subtraction unit 411a, the first
The pressure detection signal transmitted from the pressure transmitter 21 is subtracted from the target pressure signal. In the proportional-integral calculation unit 411b, a signal (deviation signal between the pressure detection signal and the first target pressure signal) from the addition / subtraction calculation unit 411a is calculated in a proportional and integral manner. An output signal from the proportional-plus-integral calculation unit 411b (a first opening command signal for commanding the opening to the first control valve 5) is transmitted to the first control valve 5, and the first control valve 5 is disclosed. This controls the flow rate of the fuel gas (process).

On the other hand, in the first control valve opening degree determination section,
It is determined that the first opening command signal is within the specified range and / or out of 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 the dead band and the second monitor switch 436 with the dead band.

When the signal at the input terminal 431 exceeds or exceeds a set value (for example, 90%) set in the first signal generator 432, the first monitor switch 433 is turned on to output a signal. In addition, it is equal to or less than the set value set in the first signal generation unit 432 and the dead band (for example, 20%)
If it drops above or beyond, the first monitor switch 4
33 is reset (OFF) to stop outputting a signal. That is, the set value set in the first signal generator 432 is set to, for example, 90%, and the first monitor switch 433 is set.
Is 20% or less, if the signal at the input terminal 431 is 70% or less or 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. Note that the connection / disconnection difference of the first monitor switch 433 may be 0%. First monitor switch 433
When the dead band of the first monitor switch 433 is 0%,
And the first monitor switch 433
Becomes the same as the set value to be reset.

On the other hand, when the signal at the input terminal 431 is equal to or smaller than the set value (for example, 10%) set in the second signal generator 435, the second monitor switch 436 is turned on.
And outputs a signal. Also, the second signal generator 435
When the value is equal to or more than the set value and the difference is equal to or more than the dead band (for example, 20%), the second monitor switch 436 is reset (OFF), and no signal is output. That is,
The set value set in the second signal generator 435 is, for example, 1
Assuming that it is 0% and the disconnection of the second monitor switch 436 is, for example, 20%, the second monitor switch 436 is reset when the signal of the input terminal 431 exceeds or exceeds 30%. Second monitor switch 436
Is output from the output terminal 437. Note that the disconnection difference of the second monitor switch 436 may be 0%. When the disconnection difference of the second monitor switch 436 is 0%, the set value at which the second monitor switch 436 is turned ON is the same as the set value at which the second monitor switch 436 is reset. An output signal from the first control valve opening degree determination unit 43 is transmitted to a second target process state quantity compensation unit 47. Hereinafter, description will be made with reference to FIG. The first
Is connected to the input terminal 471 of the second target process state quantity compensating section 47, and the output terminal 43 of the first regulating valve opening degree determining section 43 is connected.
7 and the input terminal 4 of the second target process state quantity compensator 47
76 are connected.

An output signal from the first control valve opening degree judging section 43 is inputted from an input terminal 471 and the selection switch 4
73. When the valve opening of the first control valve 5 exceeds or exceeds the set value set by the first signal generation unit 432, which is the upper limit of the specified range, and the input signal from the input terminal 471 is ON (input When a 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), a preset B-side set value 474 (0%) is selected, and the set signal is output. Is done. And the selection switch 473
Is output via the first-order lag calculator 475,
It is transmitted to the addition / subtraction operation unit 47b.

On the other hand, an output signal from the first control valve opening degree judging section 43 is inputted from an input terminal 476 and transmitted to a selection switch 478. The valve opening of the first control valve 5 is
When the input signal from the input terminal 476 is ON or lower (when the signal from the input terminal 476 is confirmed) when the input value from the input terminal 476 is equal to or smaller than the set value set by the second signal generator 435 which is the lower limit 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)
Is selected, a preset D-side set value 479 (0%) is selected, and the set signal is output. Then, the output signal from the selection switch 478 is transmitted to the addition / subtraction operation unit 47b via the primary delay operation unit 47a. Addition / subtraction unit 4
The output signal from 7b is output from output terminal 47c.

The output signal from the second target process state quantity compensating section 47 is transmitted to the addition / subtraction operation section 422a. In the addition / subtraction operation unit 422a, the output signal from the first target process state amount setting unit 412 and the output signal from the second target process state amount correction unit 47 are added, and the added signal is added to the second control valve. 6 as a target value (second target pressure signal) of the pressure in the surge tank 2. Then, an output signal from the addition / subtraction unit 422 a is transmitted to the addition / subtraction unit 421 a of the second controller 42. In the addition / subtraction operation unit 421a, the pressure detection signal is subtracted from the second target pressure signal. In the proportional-integral operation unit 421d, the addition / subtraction operation unit 42
The signal from 1a (the deviation signal between the pressure detection signal and the second target pressure signal) is calculated in a proportional and integral manner. Proportional-integral calculator 4
By transmitting a signal (a second opening command signal for commanding the opening to the second control valve 6) from the second control valve 6d to the second control valve 6, and opening and closing the second control valve 6, the fuel gas Control the (process) flow rate.

The first embodiment operates as follows.

When the opening of the first control valve 5 (first opening command signal) is within a specified range (the first signal generator 43)
2 or less, and the second signal generator 4
35 or more), the output signal of the second target process state quantity correction unit 47 becomes zero.
The target value (second target pressure signal) of the controller 42 and the target value (first target pressure signal) of the first controller 41 become the same. The control gain of the first controller 41 (the control gain of the proportional-integral calculator 411b) is set to be more sensitive than the control gain of the second controller 42 (the control gain of the proportional-integral calculator 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
0.2, integration time = about 30 seconds. Thereby, the first
When the opening degree of the control valve 5 is within the specified range and the pressure in the surge tank 2 is slightly changed, the change in the opening degree of the second control valve 6 is small, and the fuel is almost completely changed only by the first control valve 5. The flow rate of the gas 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 out of the specified range (when it exceeds or exceeds the set value of the first signal generator 432, or when the set value of the second signal generator 435 In the following case, the signal is output from the first control valve opening degree determination unit 43. That is, when the value exceeds or exceeds the set value of the first signal generator 432, the first monitor switch 433 is turned on. When the opening of the first control valve 5 exceeds or exceeds 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 operation unit 422a. As a result, the second target pressure signal of the second control valve 6 becomes the first target pressure signal.
A-side set value 472 from the first target pressure signal of the control valve 5
Is changed to a higher value, and the proportional-plus-integral operation of the proportional-plus-integral calculator 421d functions to increase the opening of the second control valve 6, so that the opening of the first control valve 5 is within the specified range. , The opening degree of the second control valve 6 gradually increases, the flow rate of the fuel gas increases, and the pressure in the surge tank 2 increases. As a result, the first pressure detection signal becomes larger than the first target pressure signal, and the feedback control reduces the opening of the first control valve 5 to fall within a specified range. Internal pressure control is stabilized. The opening of the first control valve 5 is controlled by the second signal generator 435.
If the value is equal to or less than the set value, the C-side set value 477 is selected, and the C-side set value 477 is transmitted to the addition / subtraction operation unit 422a. As a result, the second target pressure signal of the second control valve 6 is changed to a value lower than the first target pressure signal of the first control valve 5 by the C-side set value, and the proportional-integral operation unit 421d
, The opening of the second control valve 6 is reduced and the opening of the second control valve 6 is smaller than when the opening of the first control valve 5 is within the specified range. Gradually decrease and the fuel gas flow rate decreases. As a result, the opening of the first control valve 5 increases to be within the specified opening, and the surge tank 2
Internal pressure control is stabilized.

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

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

In the second embodiment, instead of the first opening command signal in the first embodiment, a first adjusting valve is used as an input signal of the first adjusting valve opening determining section 43. This is an example in which 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 (detection) of the first control valve 5 is used for determining the opening degree of the first control valve 5. Value), 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 a stick, and the process state quantity can be stabilized. This has the effect of controlling Furthermore, since the actual opening degree of the first control valve 5 is used to determine the opening degree of the first control valve 5, there is an effect that the accuracy of control of the process state quantity is improved.

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

FIG. 6 shows a third example of the process control device of the present invention.
FIG. 3 is a control block diagram of the embodiment. FIG. 7 shows a detailed control block diagram of a control operation unit with a second control gain compensation according to the third embodiment of the process control device of the present invention. 6 and 7, reference numeral 48 denotes a control operation unit with a second control gain compensation for changing a control gain based on an input signal;
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,
A selection switch 485 selects and outputs an input signal.
86 is a second proportional gain setting unit that outputs a preset proportional gain, 487 is a first-order lag calculation unit, 488 is a first integration time setting unit that outputs a preset integration time,
Reference numeral 489 denotes a selection switch for selecting and outputting an input signal.
8a is a second integration time setting unit for outputting a preset integration time, 48b is a first-order delay operation unit, 48c is an input terminal, 48d is a proportional-plus-integral operation unit for performing a proportional + integral operation on an input signal, and 48e Indicates an output terminal. Note that the set value of the first proportional gain setting section 484> the set value of the second proportional gain setting section 486, and the set value of the first integral time setting section 488> the set value of the second integral time setting section 48a. And

The third embodiment is an example in which a second control operation unit with control gain compensation 48 is added in place of the proportional-integral operation unit 421d of the first embodiment. That is, in this example, 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 first control valve opening degree judging section 43
34, the input terminal 481 of the second control operation unit with control gain compensation 48, and the output terminal 437 of the first control valve opening degree determination unit 43 and the second control operation unit with control gain compensation 48. Is connected to the input terminal 482.

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

When the first control valve opening determining section 43 determines that the opening of the first control valve 5 is within the specified range, that is, when the second control gain-added control calculating section 48 performs the first control Is not input from the control valve opening degree determination unit 43 (input terminal 4
81 and the input terminal 482 do not input any signal), the selection switch 485 selects the set value (for example, 0.01) set in the second proportional gain setting section 486, and the proportional integral calculation section 48d To communicate. Further, the selection switch 489 selects the set value (for example, 100 minutes) set in the second integration time setting section 48a, and transmits the set value to the proportional integration calculation section 48d. 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 set to the same value, for example, 30.0 kg / cm ^2. g, and 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 is slightly changed, the second controller 42
Is very insensitive, the feedback control of the second control valve 6 is temporarily stopped almost temporarily, the opening degree of the second control valve 6 becomes substantially constant, and the flow rate of the fuel gas (process) is changed. Is 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 of the first control valve 5 exceeds or exceeds the upper limit (for example, 90%) of the specified range, the second
The target value of the controller 42 is, for example, 30 kg / cm ² g, and the target value of the first controller 41 is, for example, approximately 0.5 kg / cm ² higher than the target value of 30 kg / cm ² g, for example, about 30.5 kg / cm ² g. And the control gain of the second controller 42 is set to the normal value of the proportional gain.
(E.g., 1.0), and the normal integration time (e.g.,
10 seconds). Thereby, even if the second control valve 6 and the first control valve 5 are simultaneously subjected to feedback control,
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) is higher, so the second
The opening of the second control valve 6 is larger than when the first control valve 5 is within the specified opening, and the flow rate increases. As a result, the pressure inside the surge tank 2 becomes equal to the target value of the first controller 41 (for example, 30.0).
kg / cm ² g), the first controller 41 functions to decrease the opening degree of the first control valve 5, and the opening degree of the first control valve 5 eventually becomes the upper limit of the specified range. It falls below the specified value set below, or decreases slightly, for example, the opening degree is 70%
When it becomes smaller or smaller, the first monitor switch 433
Is reset, the output of the first control valve opening degree determination unit 43 is turned off, and the target value of the second controller 42 is set to 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 gain. Then, although the opening degree of the second control valve 6 is slightly reduced by the proportional operation, the valve operation of the second control valve 6 is substantially controlled only by the integration operation. The second control valve 6 maintains the valve opening, and the feedback control is almost stopped. As a result, the opening degree of the second control valve 6 is maintained on the open side (larger side) than when the opening degree of the first control valve 5 is out of the specified range. Is 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 to the process control by the second control valve 6 having a large valve capacity, the control accuracy when the process state quantity is slightly changed can be improved. Can be improved.

If the opening degree of the first control valve 5 is smaller than the lower limit value (for example, 10%) of the specified range or smaller, the second
The target value of the controller 42 of the first controller 41 is, for example, 30 kg / cm ² g lower than the target value of the first controller 41 by about 0.5 kg / cm ² .
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 Is simultaneously controlled by a proportional + integral operation.
The target value of the controller 6 (for example, 29.5 kg / cm ² g) is the first
Is lower than the target value of the controller 41 (for example, 30.0 kg / cm ² g), so that the second control valve 6
The first control valve 5 functions to decrease the opening of
The opening degree of the second control valve 6 becomes smaller, the flow rate increases, and the pressure in the surge tank 2 decreases, as compared with the case where the value is equal to or more than (for example, 10%). When the pressure inside the surge tank 2
Falls below the target value of the controller 41 (for example, 30.0 kg / cm ² g), the first controller 41 functions to increase the opening of the first control valve 5, and then the first controller 41. The opening degree of the control valve 5 increases, and the opening degree of the first control valve 5 becomes, for example, 30%.
Above or above, the first control valve opening degree determination unit 43 is reset, and the target value of the second controller 42 is changed to the first controller 4.
For example, the same as the target value of 1 is changed to, 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. Is slightly increased by the proportional operation, but since the opening / closing operation of the second control valve 6 is substantially controlled only by the integration operation, the second control valve 6 holds the valve opening. Thus, the control by the feedback is almost stopped. Thereby, the opening degree of the second control valve 6 is maintained on a closed side (smaller side) than the state before the opening degree of the first control valve 5 becomes equal to or less than a specified value or becomes smaller, so that the surge The pressure in the tank 2 is controlled only by the first control valve 5. As a result, the pressure in the surge tank 2 can be controlled stably.

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

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

The fourth embodiment is an example in which a first control valve opening degree judging section 44 is provided in place of the first control valve opening degree judging section 43 of the first embodiment. . That is, the first
This is an example in which the target value of the second control valve 6 is changed based on the fuel gas pressure upstream of the control valve 5 and the second control valve 6.

When the pressure in the fuel gas supply header 1 increases and the inlet (upstream) pressure of the first control valve 5 and the second control valve 6 increases, the density increases with the increase in pressure.
Even when 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, a fuel gas pressure transmitter 22 is installed upstream 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. The signal is transmitted to the pressure compensation unit 44a via the input terminal 448. Then, the pressure compensation unit 44a performs a function operation on the inlet pressure detection signals of the first control valve 5 and the second control valve 6 so as to correspond to the fuel gas density accompanying the pressure change of the fuel gas, and outputs the output signal. The signal is transmitted to the first monitor switch 443 and the first monitor switch 4
By reducing the set value of 43, the target value of the second controller 42 is changed to a higher 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 it is possible to prevent the first control valve 5 from generating excessive vibration and noise. Get the effect you can. Further, the first control valve 5
The effect of suppressing control interference between the control valve and the second control valve 6 is obtained. Further, an effect of suppressing control interference between the first control valve 5 and the second control valve 6 is obtained.

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

FIG. 10 is a control block diagram of a process control device according to a fifth embodiment of the present invention. FIG. 11 shows a detailed control block diagram of the first control valve opening degree determination unit of the fifth embodiment of the process control device of the present invention. FIG.
11, 23 is a fuel gas temperature transmitter for detecting and transmitting the fuel gas temperature upstream 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 degree determination unit that outputs a signal based on a signal or / and an 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 the input signal, 457 is an output terminal,
458 is an input terminal, 459 is an input terminal, 45a is a pressure compensator that performs a function operation on the fuel gas pressure upstream of the first control valve 5 and the second control valve 6 and outputs the result, and 45b is the first control valve. Reference numeral 45c denotes a temperature compensator for multiplying an input signal and outputting the result by performing a function operation on the fuel gas temperature on the upstream side of the fifth and second control valves 6.

The fifth embodiment is an example in which a first control valve opening determining section 45 is provided in place of the first control valve opening determining section 43 of the first embodiment. . That is, the first
The 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. It is an example in which the target value is changed.

When the pressure in the fuel gas supply header 1 increases and the inlet temperatures of the first control valve 5 and the second control valve 6 decrease, the density increases as the temperature decreases. Even if the opening degree of No. 5 is within the specified range, the flow rate passing through the first control valve increases. Therefore, a fuel gas pressure transmitter 22 is installed upstream 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, and the input is detected. The signal is transmitted to the pressure compensation unit 45a via the terminal 458. On the other hand, a fuel gas temperature transmitter 23 is installed on the upstream side of the first control valve 5 and the second control valve 6 to detect the inlet temperatures of the first control valve 5 and the second control valve 6 and to input the temperature. The signal is transmitted to the temperature compensation section 45b via the terminal 459. still,
Regarding the positional relationship between the fuel gas pressure transmitter 22 and the fuel gas temperature transmitter 23, any one may be located on the upstream side. The pressure compensator 45a performs a function operation on the inlet pressure detection signals of the first control valve 5 and the second control valve 6 so as to match the density of the fuel gas accompanying the change in the pressure of the fuel gas, and outputs the output signal. To the multiplier 45c. Temperature compensation unit 45
In b, a function operation is performed on the inlet temperature detection signals of the first control valve 5 and the second control valve 6 so as to match the density of the fuel gas accompanying the temperature change of the fuel gas, and the output signal is sent to the multiplier 45c. introduce. The temperature compensating unit 45b performs a function operation on the inlet temperature detection signals of the first control valve 5 and the second control valve 6 so as to match the density of the fuel gas accompanying the temperature change of the fuel gas, and multiplies the output signals. To the unit 45c.
When the inlet temperatures of the first control valve 5 and the second control valve 6 decrease, the set value of the first monitor switch 453 is reduced by the temperature compensation unit 45b.
The target value of the second controller 42 is changed to a higher value.

According to the fifth embodiment, even when the fuel gas temperature is low, the operation is not performed at an excessive flow rate, so that it is possible to prevent the first control valve 5 from generating excessive vibration and noise. Get the effect you can. Further, the first control valve 5
The effect of suppressing control interference between the control valve and the second control valve 6 is obtained. Further, 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 is a control block diagram of a process control device according to a sixth embodiment 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 set pressure, etc.) according to the sixth embodiment of the process control device of the present invention. (A control valve opening degree and a second control valve opening degree) are compared. 12 and 13, reference numeral 3 denotes a fuel gas flow rate transmitter for detecting and transmitting the fuel gas flow rate on the downstream side of the surge tank 2.
423 is an advance control operation unit that precedesly controls the second control valve 6 based on the fuel gas flow rate. 3 shows a pressure advance control calculation unit that performs advance control of the control valve 6.

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

A flow rate transmitter 3 for detecting and transmitting the flow rate of the fuel gas is installed downstream of the surge tank 2, detects the flow rate of the fuel gas at the outlet of the surge tank 2, and performs a preceding pressure control operation.
To 423b. The advanced pressure control calculation unit 423b performs a function calculation on 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 the result to the addition / subtraction calculation unit 423a. Addition / subtraction unit 423
In a, the output signal from the second control calculation unit and the output signal from the pressure advance control calculation unit 423b are added and transmitted to the second control valve 6 as a second opening command signal.
As a result, since the first control valve 5 is almost always within the specified range, as shown in FIG. 13, the pressure of the surge tank 2 can be controlled more stably than in the first embodiment of the present invention. become.

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

FIG. 14 is a control block diagram of a process control apparatus according to a seventh embodiment 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 increasing the condensate from the condenser 11, and 13 is a high-pressure condensate for increasing the condensate from the ground condenser. Pump, 14 is a deaerator for separating dissolved oxygen in the condensate and degassing the condensate, 16 is condensate (water supply) from the deaerator
Main water pump for boosting the pressure, 17 is a ground condenser,
18 is a condensate purifier that separates impurities in condensate and purifies the condensate, 31 is a deaerator water level transmitter that detects and transmits the water level in the deaerator, and 33 is pressurized by a condensate pump. A condensate flow transmitter for detecting and transmitting the condensate flow rate, 34 is a main feedwater flow transmitter for detecting and transmitting the flow rate of feedwater boosted by the feedwater pump, and 424 is based on the condensate flow rate and / or the feedwater flow rate Precedence control calculation section 424a for precedence control of second control valve 6
Is an addition / subtraction operation unit that adds or subtracts an input signal, 424b is an addition / subtraction operation unit that adds or subtracts an input signal, and 424c is a second water level advance control operation unit that performs advance control of the second control valve 6 based on the feedwater flow rate. Reference numeral 424d denotes a first water level advance control calculation unit that performs advance 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 control the water level in a deaerator of a thermal or nuclear power plant.

The condensed water stored in the condenser 11 is pumped out and pressurized by the low-pressure condensate pump 12, and is condensed.
And water through the ground condenser 17 to the high-pressure condensate pump 13. Then, the pressure is further increased by the high-pressure condensate pump 13, and the air is removed from the deaerator 14 via the condensate flow rate transmitter 33 provided on the outlet side of the first control valve 5 and the second control valve 6 provided side by side. Water is sent to The condensate in the deaerator 14 is pumped out, pressurized by the main feedwater pump 16, and sent to a boiler (not shown) via the main feedwater flow transmitter 34.

The control device 40 controls the first control valve 5 and the second control valve 6 based on the water level in the deaerator 14 to control 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 set to each target value (the 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 section 422).

The first controller 41 comprises a first target process state quantity setting section 412 and a first control operation section 411. Addition / subtraction operation unit 411 of first control operation 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 section 412, and a proportional integral calculation section 411b is performed. To communicate. Proportional-integral calculator 411b
, A 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 the first control valve opening determination section 43
To communicate.

The second controller 42 comprises a second target process state quantity setting section 422 and a second control operation section 421. In the addition / subtraction operation 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, and the proportional integration operation unit 421 is used.
to d. In the proportional-integral operation unit 421d, the second
The proportional signal + integral calculation is performed on the deviation signal between the target water level signal and the water level detection signal, and the result is transmitted to the preceding control calculation unit 424.

On the other hand, a main feedwater flow transmitter 34 is installed between (the downstream side of) the main feedwater pump 16 and the (upstream side) of the boiler, and the main feedwater flow transmitter 34 detects the outlet feedwater flow rate. It is transmitted to the second water level advance control calculation unit 424c.
The second water level advance control operation unit 424c performs a function operation in proportion to the main water supply flow rate, and transmits the function operation to the adjustment operation unit 424b. In addition, a condensate flow rate transmitter 33 is installed between (the upstream side of) the first control valve 5 and the second control valve 6 (the downstream side) and the deaerator 14 (the upstream side). , The outlet condensate flow rate is detected, and the first water level advance control operation unit 424d
To communicate. The first water level advance control operation unit 424d performs a function operation in proportion to the condensate flow rate, and
24b. In the addition / subtraction unit 424b, the first
The output signal from the water level advance control operation unit 424d and the output signal from the second water level advance control operation unit 424c are added and transmitted to the addition / subtraction operation unit 474a. The addition / subtraction operation unit 474a adds the output signal from the second control operation unit 421 and the output signal from the addition / subtraction operation unit 474a and transmits the result to the second control valve 6 as a second opening degree command signal. According to the seventh embodiment, the opening degree of the first control valve 5 is in the vicinity of the specified range, and the opening degree of the second control valve 6 is mainly controlled in advance. 6, the change in the opening degree is reduced, and an effect is obtained in which the water level in the deaerator can be stably controlled.

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

FIG. 15 shows a control block diagram of an eighth embodiment of the process control device of the present invention. In FIG. 15, 3
Reference numeral 5 denotes a check valve for preventing backflow of the 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 control used in a nuclear power plant.

The condensed water pressurized 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 section 33, the power is transmitted to the high-pressure condensate pump 13, and the first control valve 5 and the second control valve 5 are provided side by side.
Is supplied to the control valve 6. Furthermore, high pressure condensate pump 1
The condensed water pressurized in 3 is sent to the main water supply pump 16 via the check valve 35, and is branched and 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 secure the minimum flow rate of the condensate sent from the condenser 11. That is, the condensate flow transmitter 33 is installed between the condenser 11 and the branch point on the upstream side of the high-pressure condensate pump 13, and the condensate flow sent from the condenser 11 is detected. Is transmitted to each of the 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 respective target value (the first target process state quantity setting unit 412 sets the first value).
Target flow signal, second target process state quantity setting unit 42
2) (second target flow signal set in 2),
The first control valve 5 and the second control valve 6 are controlled.

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

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

FIG. 16 is a control block diagram of a ninth embodiment of the process control device of the present invention. In FIG. 16, 6
1 is a steam supply header for supplying steam, 62 is a cooling water supply header for supplying cooling water, 64 is a heater for injecting cooling water to the steam to reduce the temperature of the steam, and 72 is a sensor 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 controlling the temperature of steam by reducing the temperature of steam.

A temperature reducer 64 is provided from the steam supply header 61 to the middle of the steam consuming side header. On the other hand, cooling water is supplied from the cooling water
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 provided side by side in the cooling water system from the cooling water supply header 62 to the cooler 64, and the first control valve 5 and the second control valve The control valve 6 is controlled to control the flow rate of the cooling water supplied to the desuperheater 64, to control the amount of temperature reduction of the steam, and to control the temperature of the steam.

The control device 40 determines the first based on the steam temperature.
The control valve 5 and the second control valve 69 are coordinated to control the steam temperature. That is, the steam temperature transmission unit 72 is installed downstream of the cooler 64 (upstream of the steam consuming header),
The first controller 41 and the second controller 4 detect the steam temperature.
2 and each of them. In the first controller 41 and the second controller 42, the steam temperature detection signal is supplied to each target value (first
The first target steam temperature signal set by the target process state quantity setting unit 412, 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 match the second target steam temperature signal set at 22).

According to the ninth embodiment, the opening of the first control valve 5 is controlled in the vicinity of the specified range, and the second control valve 6 having a large capacity is controlled with a small opening. As a result, the change in the flow rate of the cooling water is reduced, and the effect that the stable steam temperature control becomes possible is obtained.

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

FIG. 17 is a control block diagram of a process control apparatus according to a tenth embodiment of the present invention. In FIG.
Second embodiment of the tenth embodiment of the process control device of the present invention
FIG. 3 is a detailed control block diagram of a controller compensation calculation unit of FIG. 17 and 18, reference numeral 422b denotes a second target process state quantity setting unit for setting a target process state quantity of the second control valve 6, and reference numeral 49 denotes a second target process state quantity based on the opening degree of the first control valve. 492 a second controller compensation operation unit for compensating the opening of the control valve
Is an input terminal, 492 is a preset A-side set value,
A selection switch 3 for selecting and outputting an input signal;
Is a preset B-side set value, 495 is an integration operation unit for performing an integration operation on an input signal and outputting the same, 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, and 499 is a preset D side.
The reference numeral 49b denotes an addition / subtraction unit for adding or subtracting an input signal, 49c denotes an output terminal, and 49d denotes an addition / subtraction unit for adding or subtracting an input signal.

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

The controller 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 pressure transmitter 21 in the surge tank 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 and the second controller 42, the pressure detection signal is set to each target value (the first target pressure signal set by the first target process state quantity setting unit 412, 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 operation unit 411a.
, 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, and the proportional integral The calculation is 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 degree determination unit 43
In, it is determined that the opening degree of the first control valve 5 is out of the specified range or / and that the opening degree is in the specified range, and a signal is output. The output signal from the first control valve opening degree determination unit 43 is transmitted to the second controller compensation calculation unit 49. The input terminal 491 of the second controller compensation operation unit 49 and the output terminal 434 of the first control valve opening degree determination unit 43 are connected, and the input terminal 496 of the second controller compensation operation unit 49 and the first terminal 496 are connected. The output terminal 437 of the control valve opening degree determination unit 43 is connected. An output signal from the first control valve opening degree determination unit 43 is supplied to an input terminal 431.
Via the first monitor switch 43 with a dead band
The signal is transmitted to the second monitor switch 436 having the dead band 3 and the dead band.

The input terminal 4 of the first control valve opening degree judging section 43
When the signal No. 31 exceeds or exceeds the set value of the first signal generator 432, the first monitor switch 433 is turned on and outputs a signal. When the value falls below or exceeds the difference, the first monitor switch 433 is reset. The output of the first monitor switch 433 is transmitted to the output terminal 434,
The signal 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 operation unit 49b.

When the signal at the input terminal 431 of the first control valve opening degree judging section 43 becomes less than or less than the set value of the second signal generating section 435, the second monitor switch 436 is turned on to output a signal. , When it rises above the set value of the second signal generation unit 435 and above or beyond 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 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 selected. The side set value 499 is selected and transmitted to the addition / subtraction operation unit 49b.

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

When the output of the first controller 41 is within the specified range, the output of the second controller correction operation unit 49 is substantially constant, and the output change of the addition / subtraction operation unit 49d is equal to the second output. Only the output signal of the control operation unit 421 changes, and the valve opening of the second control valve 6 hardly changes. Here, the control gain of the first controller 41 is set more sensitively 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 the second
Is set to be less sensitive than the first controller. For example, the proportional gain is set to about 0.2, and the integration time = 30.
Set to seconds. By setting the control gain of the first controller 41 and the control gain of the second controller 42 in this manner, when the opening of the first control valve 5 is within the specified range, the surge If the pressure in the tank 2 changes slightly, the second
The change in the valve opening degree of the control valve 6 is reduced, and the flow rate of the fuel gas is controlled almost exclusively by 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
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. , Via the addition / subtraction operation unit 49b, and transmitted to the integration operation unit 495, and the result of the integration operation is output to the output terminal 49.
Via c, it is transmitted to the addition / subtraction operation unit 49d. As a result, it functions on the side that increases the valve opening of the second control valve 6, and
The opening of the second control valve 6 gradually increases as compared to when the first control valve 5 is within the specified opening, the fuel gas flow rate increases, and the pressure in the surge tank 2 increases. As a result, the first
The opening degree of the control valve 5 is reduced to be within the specified opening degree, and the control is stabilized.

When the opening 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. Is transmitted to the integration operation unit 495 via the addition / subtraction operation unit 49b, and the result of the integration operation is output to the output terminal 49c.
Is transmitted to the addition / subtraction operation unit 49d via

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

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

FIG. 19 shows a control block diagram of an eleventh embodiment of the process control apparatus of the present invention. In FIG.
Second embodiment of the eleventh embodiment of the process control device of the present invention
3 is a detailed control block diagram of a target setting function calculation unit of FIG.

19 and 20, reference numeral 50 denotes the second control valve 6.
Is a second target setting function calculator for changing a target process state quantity, 501 is an input terminal, 502 is a function calculator for converting and outputting an input signal according to a predetermined function set in advance, and 503 is an output terminal. Show.

The eleventh embodiment of the present invention is different from the first embodiment of the present invention in that the first control valve opening degree judging section 43 and the second target process state quantity compensating section 47 are replaced. , First
This is an example in which a function calculation unit 502 having the functions of the control valve opening degree determination unit 43 and the second target process state quantity correction unit 47 is provided.

The output signal (first opening command signal) from the first controller 41 is transmitted to the second target setting function calculating section 50. In the second target setting function calculator 50, the input signal of the input terminal 501 is transmitted to the function calculator 502. In the function operation unit 502, the input signal (the opening degree of the first control valve 5) is 0 or more and a lower limit value of a specified range (for example, 20
%) Or a signal corresponding to the input signal when it is smaller or smaller (for example, a range of -1% to 0), and is equal to or larger than a lower limit (for example, 20%) of a specified range or a second specified value (for example, 80%) or less, or output 0% signal when small,
When the value is equal to or larger than the second specified value or is larger than 100%, a signal corresponding to the input signal (for example, a range of 0 to 1%) 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%. The target value of one controller 41 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 set to 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, when the opening of the first control valve 5 is within a specified range, the pressure in the surge tank 2 is slightly changed. In addition, the change in the opening degree of the second control valve 6 decreases,
Is controlled only by the control valve 5. Therefore, the control interference between the second control valve 6 and the first control valve 5 does not occur during a constant plant load.

When the opening of the first control valve 5 is greater than or equal to the upper limit of the specified range, the output of the second target setting function calculator 50 becomes + 1% to 0%.
Signals of + 1% to 0% are transmitted. As a result, the target value of the second controller 42 is changed from + 1% to 0% higher than the target value of the first controller 41 (for example, 30 kg / cm ² g). Acts on the side to increase the opening of the second control valve 6 by the operation, and the opening of the second control valve 6 gradually becomes larger than when the first control valve 5 is within the specified opening. Since the flow rate increases, the pressure in the surge tank 2 increases. As a result, the opening of the first control valve 5 decreases and falls within the specified opening, and the control is stabilized.

When the opening of the first control valve 5 is equal to or smaller than the lower limit of the specified range, the output of the second target setting function calculator 50 becomes -1% to 0%, and the addition / subtraction calculator 422a
-1% to 0% of the signal is transmitted. Second controller 42
Is the target value of the first controller 41 (for example, 30
kg / cm ² g).
It functions on the side that reduces 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, and the pressure in the surge tank 2 decreases.
As a result, the opening of the first control valve 5 increases 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-capacity control valve) in accordance with the valve opening of the first control valve (small-capacity control valve). Has the effect of suppressing control interference between the first control valve and the second control valve.

That is, when the opening degree of the first control valve is large, 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.
Accordingly, 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 controlled in the closing direction. Then, when the opening degree of the first control valve is reduced, the target value of the process state quantity of the second control valve is reduced. When the 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. Accordingly, 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 controlled in the opening direction. Then, when the opening degree of the first control valve is increased, the target value of the process state quantity of the second control valve is increased.

[Brief description of the 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 degree determination unit of 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 compensation unit of the first embodiment of the process control device of the present invention.

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

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

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

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

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

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

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

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

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

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

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

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

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

FIG. 19 is a control block diagram of an eleventh embodiment of the 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 rate transmitter, 5 ... First control valve, 6 ... Second control valve, 7 ... First control valve opening degree transmitter, 11 ... Condenser, 12
... low-pressure condensate pump, 13 ... high-pressure condensate pump, 14 ... deaerator, 16 ... main water supply pump, 17 ... ground condenser,
18: condensate purifier, 21: pressure transmitter in surge tank,
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... First control valve opening degree determination unit, 44... First control valve opening degree determination unit, 44a, 45a.
Temperature compensating unit, 45c multiplying unit, 47 second target process state quantity compensating unit, 47a, 48b, 475, 487 ... first-order lag calculating unit, 47b, 49b, 49d, 411a, 4
21a, 422a, 423a, 424a, 424b ... addition / subtraction operation units, 47c, 48e, 49c, 434, 437, 44
4, 447, 454, 457, 503: output terminal, 48: control operation unit with second control gain compensation, 48a: second integration time setting unit, 48c, 431, 441, 448, 45
1,458,459,471,476,481,48
2,491,496,501 ... input terminal, 48d, 41
1b, 42d: Proportional-integral operation unit, 49: Second controller compensation operation unit 50: Second target setting function operation unit, 61: Steam supply header, 62: Cooling water supply header, 64: Temperature reducer,
72: steam temperature transmitter, 411: first control calculation unit, 41
2 ... first target process state quantity setting unit, 421 ... second control calculation unit, 422,422b ... second target process state quantity setting unit, 423,424 ... precedence control calculation unit, 423b ... pressure preceding control calculation 424c... Second water level precedence control calculation section, 424d... First water level precedence control calculation section, 432... First signal generation section, 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... OR, 484.
First proportional gain setting section, 486... Second proportional gain setting section, 488... First integration time setting section, 495.

Claims (8)

[Claims] 1. A large-capacity control valve and a small-capacity control valve arranged in parallel with each other so that a process state quantity matches 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 exceeds or exceeds a preset first predetermined valve opening degree, the process capacity quantity of the large capacity control valve is The target value is increased, and when the small-capacity control valve is smaller than or smaller than a second predetermined valve opening set to be equal to or smaller than the first predetermined valve opening, the control valve of the large-capacity control valve is A process control method comprising reducing a target value of the process state quantity. 2. A large-capacity control valve and a small-capacity control valve, which are arranged in parallel with each other, so that a process state quantity matches a preset target value of the process state quantity,
In the process control method for controlling the process state quantity, the target of the process state quantity of the large-capacity control valve when the small-capacity control valve is equal to or smaller than a first predetermined valve opening degree set in advance. Reducing the value, the process of the large-capacity control valve when the small-capacity control valve exceeds or exceeds a second predetermined valve opening set to the first predetermined valve opening or more A process control method characterized by increasing a target value of a state quantity. 3. A large-capacity control valve and a small-capacity control valve arranged in parallel with each other so that the process state quantity meets a preset target value of the process state quantity,
In the process control method for controlling the process state amount, when the small-capacity control valve is out of a first predetermined valve opening degree range set in advance, the process state amount of the large-capacity control valve is reduced. A target value is changed, and when the small-capacity control valve falls within a 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 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 that controls the large-capacity control valve when the small-capacity control valve falls within the second predetermined opening degree range. Item 4. The process control method according to Item 3. 6. A large-capacity control valve and a small-capacity control valve, which are arranged in parallel with each other, so that the process state quantity matches a preset target value of the process state quantity,
In the process control device for controlling the process state amount, the target value of the process state amount of the large-capacity control valve when the small-capacity control valve is out of a predetermined valve opening degree range, A process control device characterized in that the process state quantity of the large-capacity control valve is larger than a target value of the process state quantity when the small-capacity control valve is within the predetermined valve opening range. 7. 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 control unit that controls the first control valve based on the detected value of the process state quantity detected by the transmitter and the 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 first control valve, wherein a target for changing a target value of the process state quantity of the second controller in accordance with an opening degree of the first control valve. A process control device comprising a process state quantity changing unit. 8. A surge tank for storing fuel gas to be supplied to the gas turbine combustor, and a first control valve and a second control valve arranged in parallel with 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 a detection of the pressure in the surge tank detected by the pressure transmitter. A first controller for controlling the first control valve based on the target value of the pressure in the surge tank and a target value of the pressure in the surge tank. And a second controller for controlling the second control valve based on the pressure control device, wherein the surge controller controls the second control valve according to an opening degree of the first control valve. Target of pressure in surge tank An internal pressure control device for a surge tank, comprising a target pressure changing unit for changing a value.