JPH09287407A - Steam valve control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To curtail the cost for multiplication or the like by improving the reliability. SOLUTION: In the process where a steam valve at the time of normal operation moved to a completely open step, a signal which is based on a valve open degree deviation signal of a selection valve open degree instruction signal which is output from an intermediate value selector 8-1-1 and an actual degree signal which is output via a valve open degree converter from a valve open degree detector 8-4-A is output to an operator via a change-over device 8-1-10 to control a valve closing loup. When the operation is put into a normal operation and the steam valve is completely opened, a change-over condition signal is output from a majority logic device 8-1-6 to control and open loop with the result that the reliability of the device at the time of a normal operation is largely improved, all the closed loop control system of multiplexed thereby curtailing the space and the investment cost thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam valve control device for a steam turbine of a nuclear power plant, a thermal power plant or the like.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a steam turbine system in a thermal power plant.

The steam generated in the steam generator 1 is a main steam stop valve (hereinafter referred to as MSV) which is fully opened during turbine operation.
2), a steam control valve (hereinafter abbreviated as CV) 3 enters, and the amount of steam adjusted by the opening degree of the CV 3 enters the turbine 4. Then, the steam that has finished its work in the turbine 4 is discharged to the exhaust gas recovery system. A generator 5 is directly connected to the shaft end of the turbine 4 to generate electricity.

The steam valve control device adjusts the opening of MSV2 and CV3, and is composed of an opening command calculation device 6, an MSV opening control device 8 and a CV opening control device 9.

The opening command calculation device 6 uses the MSV opening from a turbine speed signal SP or the like detected by a turbine speed detector 7 installed at the sleeve end of the turbine 4 and a predetermined target speed setting or a predetermined turbine output setting (not shown). Command signal 8VC and CV
The opening degree instruction signal 9VC is calculated and output. The MSV opening control device 8 includes an MSV opening deviation calculation device 8-1, an MSV operating device 8-2, and an MSV opening detector 8-3.
The opening degree of MSV2 is adjusted. Then, the MSV function command signal 8VC and the MSV detected by the MSV opening detector 8-3
The actual opening degree signal 8VA and the MSV opening degree deviation calculating device 8-1 are input to the MSV opening degree deviation calculating device 8-1 to obtain the MSV opening degree deviation signal 8V3. Then, the opening deviation signal 8V3 is input to the MSV operator 8-2 and is converted into an MSV opening / closing mechanical signal 8VS for opening / closing the valve opening according to the deviation signal to perform closed loop control of the opening of MSV2. To do.

On the other hand, similarly, the CV function controller 9 is composed of a CV opening deviation calculator 9-1, a CV operator 9-2 and a CV opening detector 9-3 to adjust the opening of CV3.

That is, CV opening command signals 9VC and CV
CV actual opening signal 9V detected by the opening detector 9-3
A and C are input to the CV opening deviation calculation device 9-1, and thereby the CV opening deviation signal 9V3 is obtained. And
The opening deviation signal 9V3 is input to the CV operator 9-2, converted into a CV opening / closing mechanical signal 9VS for opening / closing the valve opening according to the deviation signal, and closed loop control of the CV2 opening is performed.

By the way, in the above steam valve control device, the control devices are multiplexed in order to improve the reliability and the operating rate of the control devices. This is because even if a valve, such as the MSV2, which is fully open and constant during normal operation, is erroneously controlled to close the MSV2 due to an abnormality in the control device, the turbine 4 is controlled. The steam output decreases, turbine output decreases, turbine inlet pressure rises, etc., resulting in a power plant trip, so improvement in reliability is required, and multiplexing is being performed.

An example of multiplexing is shown in FIG.
In the figure, the opening degree control of the SV2 is shown as an example. Note that FIG.
The same or corresponding parts as those shown in FIG.

In order to improve the reliability of the opening command calculation, the opening command calculation device 6 includes opening command calculation means 6-A, 6-B, 6-.
3 units of C are installed, the same calculation is performed by each means, and MSV opening command signals 8VC-A, 8VC-B, 8V
These signals are output as C-C, and these signals are input to the intermediate value selector 8-1-1 to select an intermediate value among the three signals and output the MSV function command signal 8VI. .

On the other hand, in order to improve the reliability of MSV opening detection, MSV function detectors 8-3-A, 8-3-B, 8-3 are used.
-C, 3 units are installed, and the valve opening converter 8-4
-A, 8-4-B, 8-4-C are provided, and MSV actual opening signals 8VA-A, 8VA-B,
8VA-C is obtained. Then, these signals are input to the intermediate value selector 8-1-4, the intermediate value is selected from the three signals, and the MSV actual opening signal 8VA is output.

Further, MSV opening command signal 8VI and MS
An MSV opening deviation signal 8V2 obtained by inputting the V actual relation level signal 8VA to the adder 8-1-2 is output. This signal is input to the amplifier 8-1-3, amplified to a predetermined signal, and M
The SV opening deviation signal 8V3 is output and input to the MSV operator 8-2 to open / close the MSV2.

[0013]

However, the opening command calculation means 6-A, 6-B, 6-C shown in FIG. 6 are digital calculation devices to which a microprocessor is applied and are relatively compact and have multiple functions. Although a large amount of calculation is possible and the cost and space are effectively utilized, the MSV opening deviation calculation device 8-1 that requires high-speed response control is composed of analog hardware. Therefore, when a multiplexing structure is realized for the purpose of improving reliability, the amount of analog hardware will increase. In addition, there are many types of steam turbine valves, and many valves are provided. For example, even if the same MSV has a plurality of valves, the amount of analog hardware tends to become enormous. There is a problem that the period required for inspection is long and the investment cost is high.

Further, since the adder 8-1-2 and the amplifier 8-1-3 for performing the valve closed loop control have a single system configuration, even if these become abnormal, the turbine operation is disturbed. As a result, these circuits have recently tended to be multiplexed, further increasing the space and investment costs.

Therefore, in the present invention, during normal operation, in the control of the opening of the steam valve which is fully open or fully closed,
An object of the present invention is to provide a steam valve control device that can be realized with a minimum space and a minimum investment cost without lowering the reliability of the control device as a whole.

[0016]

According to a first aspect of the present invention, there is provided an opening degree command calculating device for calculating and outputting a valve opening degree command signal, and an opening degree between a valve actual opening degree signal and a valve opening degree instruction signal of a steam valve. A steam valve control device that has a valve opening deviation calculation device that outputs an operation signal that operates a valve operating device in accordance with a deviation signal to control the steam valve, and that controls the steam valve to be fully open and constant during normal operation. The degree command calculation device is provided with at least three or more opening command calculation means for outputting the valve opening command signal and for outputting the fully opened state signal when the valve opening command signal is in the fully opened state.
The valve opening deviation device includes a majority logic unit that outputs a switching condition signal and a valve opening from each opening command calculation unit when a majority logic is established by a fully open state signal from each opening command calculation unit. Of the degree command signals, an intermediate value selector that selectively outputs the intermediate value as the selected valve opening command signal, the selected valve opening command signal that is selectively output from this intermediate value selector, and the valve opening detector opens the valve. An adder that calculates a valve opening deviation signal from the actual opening signal output through the degree converter, an amplifier that amplifies the valve opening deviation signal, and outputs a signal based on the valve opening amplification signal, While outputting a signal based on the valve opening deviation signal to the valve operating unit, when a switching condition signal is input, a switching unit that outputs a valve full open signal from the bias signal generator to the valve operating unit is provided. is there. By this means, during the process in which the steam valve during normal operation shifts to the fully open constant, the selected valve opening command signal output from the intermediate value selector and the valve opening detector output via the valve opening converter. The signal based on the valve opening deviation signal from the actual opening signal is output to the operating device via the switching device, and the valve closed loop control is performed. Next, when the operation shifts to the normal operation and the steam valve becomes constant at full open, a switching condition signal is output from the majority logic unit and open loop control is performed by the valve full open state signal. Therefore, in order to shift to the highly reliable open loop control when the valve is fully opened in normal operation, even if an abnormality occurs in the closed loop control system at this time, it does not affect the control during normal operation. , The reliability of the device during normal operation is significantly improved. Also, the time to operate the closed loop control system is extremely short time compared to the open loop control system when starting the plant, etc., and considering the reliability of the entire equipment, the space for multiplexing all of the closed loop control system, etc. And investment costs can be reduced.

According to a second aspect of the present invention, an opening degree command calculation device for calculating and outputting a valve opening degree command signal, and a valve according to an opening degree deviation signal between the actual valve opening degree signal of the steam valve and the valve opening degree instruction signal. A valve opening deviation calculation device that outputs an operation signal for operating an operating device to control a steam valve, and a valve opening deviation calculation device that controls the steam valve fully closed during normal operation. Is
At least three opening command calculation means having the same configuration for outputting the valve opening command signal and for outputting the valve opening command signal when the valve opening command signal is in the fully closed state are provided. Of the valve opening command signals from the majority logic unit that outputs the switching condition signal when the logic of majority decision is established by the fully closed state signal from each opening command calculation unit and each valve opening command signal from each opening command calculation unit. The intermediate value selector that selectively outputs the intermediate value as the selected valve opening command signal, the selected valve opening command signal that is selectively output from this intermediate value selector, and the valve opening detector via the valve opening converter. An adder that calculates a valve opening deviation signal from the output actual opening signal, an amplifier that amplifies the valve opening deviation signal and outputs a signal based on the valve opening amplification signal, and a valve opening deviation signal A signal based on the switching condition is input while the signal based on the valve is output to the valve operator. It is obtained by the provided and a switching unit for outputting the valve full close signal from the bias signal generator to the valve operating device. By this means, in the process of shifting the steam valve to the fully closed constant state during normal operation, the selected valve opening command signal output from the intermediate value selector and the valve opening detector output via the valve opening converter. The signal based on the valve opening deviation signal from the actual opening signal is output to the operating device via the switching device, and the valve closed loop control is performed. Next, when the operation is shifted to normal operation and the steam valve is fully closed and constant, a switching condition signal is output from the majority logic unit and open loop control is performed by the valve fully closed state signal.
Therefore, in order to shift to highly reliable open loop control when the valve is fully closed in normal operation, even if an abnormality occurs in the closed loop control system at this time, there is no effect on control during normal operation. No, the reliability of the device during normal operation is greatly improved. Also, the time to operate the closed loop control system is extremely short time compared to the open loop control system when starting the plant, etc., and considering the reliability of the entire equipment, the space for multiplexing all of the closed loop control system, etc. And investment costs can be reduced.

According to a third aspect of the present invention, an opening degree command calculation device for calculating and outputting a valve opening degree command signal, and a valve according to an opening degree deviation signal between a valve actual opening degree signal of a steam valve and a valve opening degree instruction signal. With a valve opening deviation calculation device that outputs an operation signal for operating the operation device to control the steam valve, and in the steam valve control device that controls the full opening constant of the steam valve during normal operation, the opening command calculation device, While outputting the valve opening command signal, it outputs a full-open equivalent bias signal that fully opens the steam valve when the valve opening command signal is in the fully open state, while fully opening the steam valve when the valve opening command signal is less than fully open. At least three opening command calculation means for outputting a bias signal to the side corresponding to the fully closed state to be closed are provided, while the valve opening deviation calculation device has a bias signal corresponding to the full opening or a fully closed state from each opening command calculation means. Input the bias signal to the equivalent side, and A first intermediate value selector that selects an intermediate value and outputs it as a first intermediate bias signal, and inputs each valve opening command signal to select an intermediate value from these signals and use it as a second intermediate bias signal. A second intermediate value selector that outputs, and an adder that calculates a valve opening deviation signal between the second intermediate bias signal and the actual opening signal output from the opening detector through the valve opening converter, An amplifier that amplifies the valve opening deviation signal and outputs a signal based on the valve opening deviation signal, and selects a high value of the signal based on the valve opening deviation signal and the first intermediate bias signal to operate the operation signal. And a high value selector for outputting to the container. By this means, in the process of shifting to the steam valve full-open constant during normal operation, the valve opening deviation between the second intermediate bias signal and the actual opening signal output from the opening detector via the valve opening converter. A signal based on the signal is selected by the high value selector and valve closed loop control is performed. Next, when the operation is shifted to normal operation and the steam valve is kept fully open, the first intermediate bias signal, which is a signal on the fully open side, is selected by the high value selector, and open loop control is performed. Therefore, in order to shift to the highly reliable open loop control when the valve is fully opened in normal operation, even if an abnormality occurs in the closed loop control system at this time, it does not affect the control during normal operation. ,
The reliability of the device during normal operation is greatly improved. Also, the time to operate the closed loop control system is extremely short time compared to the open loop control system when starting the plant, etc., and considering the reliability of the entire equipment, the space for multiplexing all of the closed loop control system, etc. And investment costs can be reduced.

According to a fourth aspect of the present invention, an opening command calculation device for calculating and outputting a valve opening command signal, and a valve according to an opening deviation signal between a valve actual opening signal of a steam valve and a valve opening command signal. In a steam valve control device that has a valve opening deviation calculation device that outputs an operation signal that operates an operation device to control a steam valve, and that controls the constant closing of the steam valve during normal operation, the opening command calculation device is When the valve opening command signal is less than fully closed, the valve opening command signal is output and the bias signal corresponding to fully closing the steam valve when the valve opening command signal is fully closed is output. , At least three opening command calculation means for outputting a bias signal on the side of a fully open corresponding signal for fully opening the steam valve are provided, while the valve opening deviation calculation device is equivalent to fully closed from each opening command calculation means. Input a bias signal or a bias signal to the side corresponding to full open. A first intermediate value selector for selecting an intermediate value in the above and outputting it as a first intermediate bias signal, and inputting each valve opening command signal, selecting an intermediate value among these signals and selecting a second intermediate bias An adder that calculates a valve opening deviation signal between a second intermediate value selector that outputs a signal and a second intermediate bias signal and an actual opening signal that is output from the opening detector through the valve opening converter. And an amplifier that amplifies the valve opening deviation signal and outputs a signal based on the valve opening deviation signal, and operates by selecting a low value of the signal based on the valve opening deviation signal and the first intermediate bias signal. A low value selector for outputting a signal to the operating device is provided. By this means, in the process of shifting to the steam valve fully closed state during normal operation,
A signal based on the valve opening deviation signal between the second intermediate bias signal and the actual opening signal output from the opening detector via the valve opening converter is selected by the low value selector to perform the valve closed loop control. . Next, when the operation is shifted to the normal operation and the steam valve is fully closed and constant, the first intermediate bias signal, which is a signal on the fully closed side, is selected by the low value selector and open loop control is performed. Therefore, in order to shift to highly reliable open loop control when the valve is fully closed in normal operation, even if an abnormality occurs in the closed loop control system at this time, there is no effect on control during normal operation. No, the reliability of the device during normal operation is greatly improved. Also, the time to operate the closed loop control system is extremely short time compared to the open loop control system when starting the plant, etc., and considering the reliability of the entire equipment, the space for multiplexing all of the closed loop control system, etc. And investment costs can be reduced.

[0020]

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

FIG. 1 is a block diagram of a steam valve control device showing a first embodiment of the present invention, and the same reference numerals as those in FIGS. 5 and 6 showing a conventional example indicate the same or corresponding parts. 1, a switch 8-1-10 is provided between the amplifier 8-1-3 and the MSV operator 8-2, and a bias signal generator 8-1-7 is connected to the switch 8-1-10. Is provided and connected to the opening instruction calculation means 6-A, 6-B, 6-C to provide a majority logic 8-1-6, while the MSV opening detectors 8-3-B and MSV shown in FIG. The opening degree detector 8-3-C, the valve opening degree converter 8-4-B, and the valve opening degree converter 8-4-C are deleted to remove the MS.
Only the V opening detector 8-3-A and the valve opening converter 8-4-A are used.

Here, the switching device 8-1-10 outputs a signal based on the valve opening deviation signal 8V2 to the MSV operating device 8-2, and when the switching condition signal 8V5 is input, the bias signal generator 8-. The valve full-open signal 8V6 from 1-7 is output to the valve operating device 8-2. The majority logic 8-1-6 outputs the switching condition signal 8V5 when the logic of majority is established by the fully open state signals from the respective opening command calculation means 6-A, 6-B, 6-C. .

Next, with respect to the operation of the first embodiment of the present invention, the MSV in which the valve is fully opened and kept constant during normal turbine operation.
The case of 2 will be described.

First, in the opening command calculation device 6D, the MSV opening command signals 8VC-A, 8VC-B and 8VC-C are output from the respective opening command calculation means 6-A, 6-B and 6-C. On the other hand, the execution condition signals 8V4-A, 8V4-B, and 8V that make the MSV opening command signal a fully open signal when the MSV opening command signal is fully open
4-C is output. Next, in the intermediate value selector 8-1-1, the MSV opening command signals 8VC-A, 8VC-B, 8V.
C-C is input, an intermediate value is selected from the three signals, and the MSV opening command signal 8V1 is output to the adder 8-1-2. Subsequently, the MSV opening command signal 8V1 and the MSV actual opening signal 8V are displayed by the adder 8-1-2 with the symbols shown in the figure.
MSV opening deviation signal 8V2 obtained by adding A-A
Is amplified by the amplifier 8-1-3 and output to the switch 8-1-10. In addition, the bias signal 8V6 that fully opens the MSV2 is output from the bias signal generator 8-1-7 to the switching device 8-.
It is output to 1-10.

Here, when the MSV opening control is continuously controlled at an intermediate opening, the opening command calculating means 6-A, 6-B, 6-C of the opening command calculating device 6D to the majority logic unit 8-1. -6
Execution condition signals input to 8V4-A, 8V4-B, 8V
Since two or more 4-C are not in the fully open state, the condition is not satisfied, and the output of the switching condition signal 8V5 is prohibited. As a result, the switch 8-1-10 is connected between b and c, and the MSV operator 8-2 outputs the MSV opening command signal 8VC-.
Closed loop control is performed by a signal having an intermediate value of A, 8VC-B, and 8VC-C.

When the MSV opening command signal is in the fully open state, the execution condition signals 8V4-A, 8V4-B, 8V4-.
Two or more C are in the fully open state, the execution condition is satisfied, and the switching condition signal 8V5 is output. Thereby, the switching device 8-1
-10 is connected between a and c, and the MSV manipulator 8-2 receives the bias signal 8V6 from the bias signal generator 8-1-7 for keeping the valve fully open and constant, thereby keeping the MSV fully open and constant. Maintained.

As described above, according to the first embodiment of the present invention, the closed loop control is changed to the open loop control at the time when the MSV opening is controlled so that the full open value is constant, and the MSV2 is maintained at the full open constant. Therefore, even if the amplifier 8-1-3, the adder 8-1-2, the MSV opening detector 8-3-A become abnormal, and an abnormal signal is output, the MSV opening is changed. Has no effect.

As described above, it is possible to reduce the amount of analog hardware for MSV opening control and to realize highly reliable MSV opening control. The switching device 8-1-10, the bias signal generator 8-1-7, the majority logic device 8-1-6 and the like have sufficient reliability and can be easily realized with simple hardware, and therefore are not required to be used. It doesn't increase. Therefore, it is possible to obtain the effects of reducing the space of the control device, reducing the investment cost, and shortening the inspection period without lowering the reliability.

FIG. 2 is a block diagram of a steam valve control device showing a second embodiment of the present invention, and the same reference numerals as those in FIGS. 5 and 6 showing a conventional example indicate the same or corresponding parts. 2, the amplifier 8-1-3 and the TBV operator 8-2A
Between the switch 8-1-10A and the switch 8-1-10
A bias signal generator 8-1-7A is provided in connection with A, and a majority logic unit 8-1-6A is provided in connection with opening instruction calculation means 6-A, 6-B, 6-C. MS of Figure 6
V opening detector 8-3-B and TBV opening detector 8-3-C
The valve opening converter 8-4-B and the valve opening converter 8-4-C are deleted, and only the MSV opening detector 8-3-AA and the valve opening converter 8-4-AA are provided. .

Here, the switching device 8-1-10A outputs a signal based on the valve opening deviation signal 8V2 to the TBV operating device 8-2A, and when the switching condition signal 8V2A is input, the bias signal generator 8-. Valve full-closed signal 8V6 from 1-7A
A is output to the TBV valve operator 8-2A. The majority logic unit 8-1-6A has opening degree command calculating means 6-A,
The switching condition signal 8V5A is output when the majority logic is established by the fully closed state signals from 6-B and 6-C.

Next, the operation of the second embodiment of the present invention will be described when it is applied to a turbine bypass valve (hereinafter referred to as TBV) in which the valve is fully closed and fixed during normal turbine operation.

First, in the opening degree instruction calculation device 6E, the TBV opening degree instruction signals 8VC-AA, 8VC-BA, 8VC-CA are output from the respective opening degree instruction calculation means 6-A, 6-B, 6-C. On the other hand, when the TBV opening command signal is in the fully closed state, the execution condition signals 8V4-AA and 8V4- are set to the fully closed state signal
BA, 8V4-CA is output. Next, in the intermediate value selector 8-1-1, TBV opening command signals 8VC-A, 8V
CB and 8VC-C are input, an intermediate value is selected from the three signals, and the TBV opening command signal 8V1 is added to the adder 8
-1-2 is output. Subsequently, a TBV opening degree deviation signal 8V2 obtained by adding the TBV opening degree instruction signal 8V1 and the TBV actual opening degree signal 8VAA is amplified by the amplifier 8-1-3 by the adder 8-1-2 with the reference numeral. Switcher 8-1
Output to -10A. Also, the bias signal generator 8-
A bias signal 8V6A for fully closing the turbine bypass valve is output from 1-7A to the switch 8-1-10A.

Here, when the TBV opening control is continuously controlled at an intermediate opening, the opening instruction calculation means 6-A, 6-B, 6-.
Since the execution condition signals 8V4-AA, 8V4-BA, and 8V4-CA that are input from C to the majority logic unit 8-1-6A are not in the fully closed state, the execution condition is not satisfied, and the switching condition signal 8V5A Output is prohibited. As a result, in the switching device 8-1-10A, the connection between b and c is established, and the TBV operating device 8-2A is operated by the TBV opening command signal 8VC.
Closed loop control is performed by any one of the signals -AA, 8VC-BA, and 8VC-CA.

When the TBV opening command signal is in the fully closed state, the execution condition signals 8V4-AA, 8V4-BA, 8V.
Two or more 4-CAs are fully closed to satisfy the execution condition, and the switching condition signal 8V5A is output. As a result, the switching device 8-1-10A is connected between a and c and the TBV operating device 8 is connected.
-2A receives a bias signal 8V6A from the bias signal generator 8-1-7A to keep the valve fully closed and constant, and the turbine bypass valve is kept constant and fully closed.

As described above, according to the second embodiment of the present invention, the closed loop control is changed to the open loop control and the turbine bypass valve is completely closed at the time when the TBV opening is controlled to the constant fully closed value. Since it is possible to maintain the closed constant, the amplifier 8-1
-3, adder 8-1-2, TBV opening detector 8-3-A
Even if A or the like becomes abnormal and an abnormal signal is output, it does not affect the TBV opening.

As described above, it is possible to reduce the amount of analog hardware for TBV opening control and to realize highly reliable TBV opening control. The switch 8-1-10A, the bias signal generator 8-1-7A, the majority logic 8-1-
6A and the like have sufficient reliability and can be easily implemented with simple hardware, so the space does not increase. Therefore, it is possible to obtain the effects of reducing the space of the control device, reducing the investment cost, and shortening the inspection period without lowering the reliability.

Next, a third embodiment of the present invention will be described with reference to FIG.

In FIG. 3, the same reference numerals as those in FIGS. 5 and 6 showing the conventional example indicate the same or corresponding portions, and FIG.
Is a high value selector 8-1-8 between the amplifier 8-1-3 and the MSV operator 8-2 of FIG. 6, and the input side is the opening command calculation means 6-A, 6-B, 6-C. The MSV opening detector 8-3-B and the MSV opening detector shown in FIG. 6 are connected, and an intermediate value selector 8-1-9 whose output side is connected to the high value selector 8-1-8 is additionally provided. 8-3-C, valve opening converter 8-4-B, and valve opening converter 8-4-C are deleted, and MSV opening detector 8-3-
Only A is set.

Here, the high value selector 8-1-8 has a signal based on the valve opening deviation signal 8V2 and an intermediate bias signal 8V9.
Select either high value from
-2. The intermediate value selector 8-1-9 inputs a bias signal corresponding to full opening or a large bias signal to the side corresponding to full closing from the opening command calculating means 6-A, 6-B, 6-C, respectively. Then, an intermediate value is selected from among these and output as an intermediate bias signal 8V9.

Next, a case where the operation of the third embodiment of the present invention is applied to an MSV in which the valve is fully opened will be described.

First, in the opening degree instruction calculation device 6F, the MSV opening degree instruction signals 8VC-A, 8VC-B, 8VC-C are output from the respective opening degree instruction calculation means 6-A, 6-B, 6-C. On the other hand, the fully open equivalent bias signal is output in the fully open state, and the fully closed equivalent signal is output when less than fully open.
Next, in the intermediate value selector 8-1-1, the MSV opening command signals 8VC-A, 8VC-B and 8VC-C are input, and an intermediate value is selected from the three signals, and the MSV opening is selected. Command signal 8V1 is output to adder 8-1-2. The MSV opening deviation signal 8V2 obtained by adding the MSV opening command signal 8V1 and the MSV actual opening signal 8VA-A by the adder 8-1-2 is amplified by the amplifier 8-1-3. It is output to the high price selector 8-1-8.

Each function command value calculating means 6-A, 6
From -B, 6-C, when the full open state is reached, the bias signals 8V8-A, 8V8- for keeping the MSV opening constant.
B and 8V8-C are output respectively. Although the output method of this bias signal is not shown, for example, the MSV function command signals 8VC-A, 8VC in the opening command calculation device 6F are used.
-B, 8VC-C signal level is monitored, and when this signal reaches the fully open value, a bias signal for keeping the MSV constant at full open is output, while the MSV opening command signal 8V
When C-A, 8VC-B, and 8VC-C are less than the full open value, a large negative signal is output. The bias signals 8V8-A, 8V8-B, 8V8-C are applied to the intermediate value selector 8
It is input to -1-9, an intermediate value of the three signals is selected and output as a bias signal 8V9.

The high value selector 8-1-8 receives the MSV opening deviation signal 8V3 and the bias signal 8V9, selects the higher one of the two signals, and outputs the MSV opening deviation signal 8V10. This signal is sent to the MSV controller 8-
2 is input.

Here, when the MSV opening control is continuously controlled at an intermediate opening, the bias signal 8V8 from the opening command calculation means 6-A, 6-B, 6-C of the opening command calculation device 6F.
-A, 8V8-B and 8V8-C are large negative signals, and the bias signal 8V9 is also a large negative signal. This large negative signal amount is set to a value larger than the maximum negative signal from the amplifier 8-1-3 for continuously controlling the valve opening. As a result, the high price selector 8-1-8 selects and outputs the signal of the amplifier 8-1-3, and the MSV operator 8
-2, MSV opening command signals 8VC-A, 8VC-B,
Closed loop control is performed by any signal of 8VC-C.

After that, when the MSV opening command signal reaches the fully open value, the bias signals 8V8-A, 8V8-B, 8V8-C.
Becomes a positive signal for fully opening the valve, and the bias signal 8V9
Is also a positive signal. As a result, the output signal 8V3 of the high value selector 8-1-8 always becomes a positive signal, and the valve opening is maintained at the full open constant.

As described above, according to the third embodiment of the present invention, when the MSV opening is controlled so that the full-open value is constant, the MSV is opened.
Since only a positive signal of full opening is input to the V manipulator 8-2, MSV2 can be kept constant at full opening. That is, the amplifier 8-1-3, the adder 8-1-2, the MSV opening degree detector 8-3-A, etc. become abnormal, and an abnormal closed signal (negative signal) is output to the amplifier 8-1-3. If it occurs in the output of
Since the positive bias signal 8V9 becomes the output of the high value selector 8-1-8, it does not affect the opening degree of the MSV2.

As a result, it is possible to reduce the amount of analog hardware for controlling the MSV opening and realize highly reliable MSV opening control. Since the high value selector 8-1-8 and the intermediate value selector 8-1-9 have sufficient reliability, the addition of these does not reduce the reliability and the amount of analog hardware is small. Therefore, it has little effect on space and cost. Therefore, it is possible to obtain the effects of reducing the space of the control device, reducing the investment cost, and shortening the inspection period without lowering the reliability.

Next, a fourth embodiment of the present invention will be described with reference to FIG.

In FIG. 4, the same reference numerals as those in FIGS. 5 and 6 showing the conventional example indicate the same or corresponding portions, and FIG.
Is a low value selector 8-1-8A between the amplifier 8-1-3 and the MSV operator 8-2 of FIG. 6, and the input side is opening command calculation means 6-A, 6-B, 6-C. And an intermediate value selector 8-1-9A whose output side is connected to the low value selector 8-1-8A are additionally provided, while the MSV opening detectors 8-3-B and T shown in FIG.
The BV opening detector 8-3-C, the valve opening converter 8-4-B, and the valve opening converter 8-4-C are deleted to remove the TBV opening detector 8
Only -3-A and valve opening converter 8-4-A are used.

Here, the low value selector 8-1-8A has a signal based on the valve opening deviation signal 8V2 and an intermediate bias signal 8V.
9A is selected as a low value, and the operation signal is output to the TBV operator 8-2A. The intermediate value selector 8-1-9A is
A bias signal corresponding to full opening or a large bias signal to the side corresponding to full closing is input from each of the opening command calculation means 6-A, 6-B, 6-C, and an intermediate value is selected from these to select an intermediate bias signal. Output as 8V9A.

Next, a case will be described in which the operation of the fourth embodiment of the present invention is applied to a turbine bypass valve (hereinafter referred to as TBV) in which the valve is fully closed and fixed.

First, in the opening degree instruction calculation device 6G, TBV opening degree instruction signals 8VC-AA, 8VC-BA, 8VC-CA are output from the respective opening degree instruction calculation means 6-A, 6-B, 6-C. On the other hand, a fully closed equivalent bias signal is output in the fully closed state, and a large signal equal to or more than fully opened is output when less than fully closed. Next, in the intermediate value selector 8-1-1,
TBV opening command signal 8VC-AA, 8VC-BA, 8V
C-CA is input, an intermediate value is selected from the three signals, and the TBV opening command signal 8V1 is output to the adder 8-1-2. Then, the TBV opening command signal 8V1 and the TBV actual opening signal 8V are indicated by the symbols shown by the adder 8-1-2.
TBV opening deviation signal 8V2 obtained by adding A-A
Is amplified by the amplifier 8-1-3 and the low value selector 8-
It is output to 1-8A.

Each function command value calculating means 6-A, 6
From -B, 6-C, when the fully closed state, the bias signals 8V8-AA, 8V8 for keeping the TBV opening constant.
-BA and 8V8-CA are output respectively. Although the output method of this bias signal is not shown, for example, the TBV function command signal 8VC-A in the opening command calculation device 6G is used.
The signal level of A, 8VC-BA, 8VC-CA is monitored, and when this signal reaches the fully closed value, a bias signal for keeping the turbine bypass valve fully closed is output, while the TBV opening command is issued. Signal 8VC-A, 8VC-B, 8V
When C-C is less than the fully closed value, a large positive signal is output. Then, these bias signals 8V8-AA,
8V8-BA and 8V8-CA are intermediate value selectors 8-1-9
It is input to A, an intermediate value of the three signals is selected and output as a bias signal 8V9A.

In the low value selector 8-1-8A, the TBV opening deviation signal 8V3A and the bias signal 8V9A are input, the lower one of the two signals is selected, and this signal is selected. -2A is input.

Here, when the TBV opening control is continuously controlled at the intermediate opening, the bias signal 8V8 from the opening command calculating means 6-A, 6-B, 6-C of the opening command calculating device 6G.
-AA, 8V8-BA, 8V8-CA are large positive signals, and the bias signal 8V9A is also a large positive signal. This large positive signal amount is set to a value larger than the maximum positive signal from the amplifier 8-1-3A for continuously controlling the valve opening. As a result, the low value selector 8-1-8
In A, the signal from the amplifier 8-1-3 is selected and output, and in the TBV operator 8-2A, the TBV opening command signal 8V.
Closed loop control is performed by a signal of any one of C-AA, 8VC-BA, and 8VC-CA.

After that, when the TBV opening command signal becomes the fully closed value, the bias signals 8V8-AA, 8V8-BA, 8V8.
-CA becomes a negative signal for fully closing the valve, and the bias signal 8V9 also becomes a negative signal. As a result, the low value selector 8-1
A negative signal is output from -8A and the valve opening is maintained at a fully closed constant.

As described above, according to the fourth embodiment of the present invention, TB is controlled when the TBV opening is controlled so that the fully closed value is constant.
Since only a positive signal for opening the valve is input to the V manipulator 8-2A, the turbine bypass valve can be kept fully closed. That is, the amplifier 8-1-3 and the adder 8-1-
2. When the TBV opening detector 8-3-A becomes abnormal and an abnormal closed signal (negative signal) is generated at the output of the amplifier 8-1-3, the negative bias signal 8V9A is output. Since it is the output of the low value selector 8-1-8A, it does not affect the opening degree of TBV2.

This makes it possible to reduce the amount of analog hardware for TBV opening control and to realize highly reliable TBV opening control. Since the low value selector 8-1-8A and the intermediate value selector 8-1-9A have sufficient reliability, the addition of these does not reduce the reliability and the amount of analog hardware is small. Therefore, it has little impact on space and cost. Therefore, it is possible to obtain the effects of reducing the space of the control device, reducing the investment cost, and shortening the inspection period without lowering the reliability.

In the first to fourth embodiments, the example in which the opening degree instruction calculation device is tripled has been described. However, the function of the majority logic unit can be changed or the function can be changed even in a doubled configuration, a single system configuration or another multiplex configuration. By deleting it, the same effect as the embodiment can be obtained. Further, the invention is not limited to the MSV and TBV, and can be applied to various valve control devices that are arranged around the turbine and normally open or close the valve normally.

[0060]

As described above, according to the invention of claim 1, in the process of shifting the steam valve to the fully open constant state during the normal operation, the valve opening degree of the selection valve opening degree command signal and the actual opening degree signal is increased. While the valve closed-loop control is performed by the signal based on the deviation signal, when the steam valve goes to the normal operation and the steam valve is kept fully open, open-loop control is performed by the valve fully-open signal, which greatly improves the reliability of the device during normal operation. In consideration of the reliability of the entire device, it is possible to reduce the space and investment cost for multiplexing all the closed loop control systems.

According to the second aspect of the present invention, in the process of shifting the steam valve to the fully closed constant state during normal operation, the signal based on the valve opening deviation signal between the selected valve opening command signal and the actual opening signal is used. While performing the valve closed loop control, when shifting to normal operation and the steam valve is fully closed constant, open loop control is performed by the valve fully closed state signal, so the reliability of the device during normal operation is greatly improved, Considering the reliability of the entire device, it is possible to reduce the space and investment cost for multiplexing all the closed loop control systems.

According to the third aspect of the present invention, in the process of shifting to the steam valve full opening constant during the normal operation, the valve closed loop control is performed by the signal based on the valve opening deviation signal between the second intermediate bias signal and the actual opening signal. On the other hand, when the steam valve is fully opened and becomes constant at the time of normal operation, the open loop control by the first intermediate bias signal is performed, so the reliability of the device during normal operation is significantly improved and the reliability of the entire device is improved. Considering the nature, it is possible to reduce the space and investment cost for multiplexing all the closed loop control systems.

According to the fourth aspect of the present invention, in the process of shifting to the fully closed state of the steam valve during the normal operation, the valve closing loop is performed by the signal based on the valve opening deviation signal between the second intermediate bias signal and the actual opening signal. On the other hand, when the steam valve is fully closed after the normal operation, the open loop control is performed on the first intermediate bias signal, which is the signal on the fully closed side, so the reliability of the device during normal operation is greatly improved. In consideration of the reliability of the entire device, it is possible to reduce the space and investment cost for multiplexing all the closed loop control systems.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an MSV valve control device showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a TBV valve control device showing a second embodiment of the present invention.

FIG. 3 is a configuration diagram of an MSV valve control device showing a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a TBV valve control device showing a fourth embodiment of the present invention.

FIG. 5 is a system configuration diagram of a steam turbine.

FIG. 6 is a configuration diagram of a conventional MSV valve control device.

[Explanation of symbols]

 6 Opening degree command calculating device 6-A, 6-B, 6-C Opening degree command calculating means 8-1 MSV opening deviation calculating device 8-2 MSV operator 8-3 MSV opening detector 8-1-1 , 8-1-4, 8-1-9 Intermediate value selector 8-1-2 Adder 8-1-3 Amplifier 8-1-6 Majority decision logic unit 8-1-7 Bias signal generator 8-1- 8 High value selector 8-1-8A Low value selector 8-4-A, 8-4-B, 8-4-C Valve opening converter

Claims (4)

[Claims] 1. An opening command calculation device for calculating and outputting a valve opening command signal, and a valve operating device operated according to an opening deviation signal between the actual valve opening signal of the steam valve and the valve opening command signal. In the steam valve control device having a valve opening deviation calculation device for controlling the steam valve by outputting an operation signal for controlling the steam valve to be fully open and constant during normal operation, the opening command calculation device is configured to open the valve opening device. A valve opening degree command signal, and at least three opening degree command calculation means for outputting the fully opened state signal when the valve opening degree command signal is in the fully opened state. A majority logic unit that outputs a switching condition signal when the logic of majority decision is established by the fully open state signal from the opening command calculation means and the valve opening command signals from the opening command calculation means. Selectively output the intermediate value as the selected valve opening command signal. The valve opening deviation between the intermediate value selector and the selected valve opening command signal selectively output from this intermediate value selector and the actual opening signal output from the valve opening detector via the valve opening converter. An adder that calculates a signal, an amplifier that amplifies the valve opening deviation signal and outputs a signal based on the valve opening amplification signal, and a signal that outputs the signal based on the valve opening deviation signal to the valve manipulator ,
A steam valve control device comprising: a switching device that outputs a valve full-open signal from a bias signal generator to the valve operating device when the switching condition signal is input. 2. An opening command calculation device for calculating and outputting a valve opening command signal, and a valve operating device operated according to an opening deviation signal between the actual valve opening signal of the steam valve and the valve opening command signal. With a valve opening deviation calculation device that outputs an operation signal to control the steam valve, and in a steam valve control device that performs constant control of fully closing the steam valve during normal operation, the opening command calculation device is the While providing at least three opening command calculation means for outputting a valve opening command signal and outputting a fully closed state signal when the valve opening command signal is in a fully closed state, the valve opening deviation device is A majority logic device that outputs a switching condition signal when the majority logic is established by the fully closed state signals from the opening instruction calculation means;
An intermediate value selector that selectively outputs the intermediate value of the valve opening command signals from the opening command calculating means as a selected valve opening command signal, and a selected valve opening that is selectively output from the intermediate value selector. Degree command signal and an adder that calculates a valve opening deviation signal between the valve opening detector and the actual opening signal output from the valve opening converter, and an amplifier that amplifies the valve opening deviation signal, An amplifier that outputs a signal based on the opening amplification signal and a signal based on the valve opening deviation signal are output to the valve manipulator, while the switching condition signal is input, the valve fully closed signal from the bias signal generator. Is provided to the valve operating device, and a steam valve control device. 3. An opening command calculation device for calculating and outputting a valve opening command signal, and a valve operating device operated according to an opening deviation signal between the actual valve opening signal of the steam valve and the valve opening command signal. In the steam valve control device having a valve opening deviation calculation device for controlling the steam valve by outputting an operation signal for controlling the steam valve to be fully open and constant during normal operation, the opening command calculation device is configured to open the valve opening device. Output command signal and output a bias signal corresponding to full opening to fully open the steam valve when the valve opening command signal is fully open, while fully opening the steam valve when the valve opening command signal is less than full open. At least three or more opening command calculation means for outputting a bias signal to the side corresponding to full closure to be closed are provided, while the valve opening deviation calculation device is configured such that the bias signal corresponding to the full opening from each opening command calculation means is provided. Or a bias signal to the side corresponding to the fully closed state A first intermediate value selector for inputting and selecting an intermediate value among these and outputting as a first intermediate bias signal, and for inputting each of the valve opening command signals, selecting an intermediate value among these signals A second intermediate value selector which outputs a second intermediate bias signal and an actual opening signal output from an opening detector of the second intermediate bias signal through a valve opening converter. Degree deviation signal, an amplifier that amplifies the valve opening deviation signal and outputs a signal based on the valve opening deviation signal, a signal based on the valve opening deviation signal, and the first intermediate bias signal And a high value selector that outputs a manipulation signal to the manipulator by selecting a higher value from the steam valve control device. 4. An opening command calculation device for calculating and outputting a valve opening command signal, and a valve operating device operated according to an opening deviation signal between the actual valve opening signal of the steam valve and the valve opening command signal. And a valve opening deviation calculation device that controls the steam valve by outputting an operation signal to control the steam valve fully closed and constant during normal operation. Degree command signal is output, while the valve opening command signal outputs a fully-closed equivalent bias signal that fully closes the steam valve when the valve opening command signal is fully closed, while the valve opening command signal is less than fully closed, At least three or more opening command calculation means for outputting a bias signal on the side of the full-open corresponding signal for fully opening the steam valve are provided, while the valve opening deviation calculation device is configured so that the valve opening deviation calculation means outputs the bias signals from the opening command calculation means. Closed equivalent bias signal or bias signal to the fully open equivalent side , A first intermediate value selector that selects an intermediate value among these signals and outputs it as a first intermediate bias signal, and each of the valve opening command signals is input, and an intermediate value is selected among these signals. A second intermediate value selector that selects and outputs a second intermediate bias signal, and a valve opening of the second intermediate bias signal and an actual opening signal output from the opening detector through a valve opening converter. Degree deviation signal, an amplifier that amplifies the valve opening deviation signal and outputs a signal based on the valve opening deviation signal, a signal based on the valve opening deviation signal, and the first intermediate bias signal And a low value selector that outputs a manipulation signal to the manipulator by selecting a lower value from the steam valve control device.