JPH06117202A - Steam turbine inlet pressure control device - Google Patents

Abstract

PURPOSE:To make a stable pressure control to increase control accuracy and responsiveness by switching over the control constants of a regulator according to the opening and closing conditions of a governing valve and a turbine bypass valve, and correcting a governing flow amount instruction signal and a turbine bypass flow amount instruction signal into actual flow amount by their respective functional devices. CONSTITUTION:Setting units 24a, 24b, 24c set control constants in a regulator 23 through contacts 25a, 25b, and 25c when a governing valve 5 only is open, a turbine bypass valve 9 only is open, and both valves 5 and 9 are open respectively. A governing valve flow amount signal E2 is inputted into a functional device 26, corrected to a signal for actual steam flow amount, and the corrected signal E8 is outputted into an adder 22. A functional device 27 corrects a turbine bypass valve flow amount signal E3 to a signal for actual steam flow amount, and outputs the corrected signal E9 to the adder 22. Thus a stable pressure control is always made to increase control accuracy and responsiveness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine inlet pressure control device for a power plant having a turbine bypass valve in a steam turbine.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a steam turbine controller in a nuclear power plant, which is composed of an electric pressure controller and a mechanical turbine controller.

The electric pressure control device 1 is composed of an electric circuit, and the mechanical turbine control device 2 is composed of a mechanical system such as a lever and a cam for transmitting a calculation signal. The steam generated by the steam generator 3 enters a steam control valve 5 that adjusts the flow rate of steam to the steam turbine 6 through a main steam stop valve 4 that is fully opened during operation of the steam turbine, and the adjusted steam is steam. It flows into the turbine 6 and rotates the turbine to generate a generator 7.
Power generation. The steam that has finished its work in the steam turbine 6 is discharged to the condenser 8. A pipe is provided on the inlet side of the main steam stop valve 4 to allow excess steam to escape to the condenser 8 through the turbine bypass valve 9.

Generally, the power generation of a nuclear power plant is adjusted by allowing the steam generated by the steam generator 3 to flow into the steam turbine 6 as it is. As a means for this, the pressure on the inlet side of the main steam stop valve 4 is used. (Normally, this pressure is referred to as turbine inlet pressure)
It is performed by adjusting the opening degree of. On the other hand, the turbine bypass valve 9 is normally closed at the front, and is opened when the rise of the turbine inlet pressure cannot be adjusted only by the steam control valve 5.

In the mechanical turbine control device 2 for performing the above control, the output setting signal M1 from the speed output setting device 10 for controlling the speed and output of the turbine and the electric / mechanical converter 11 are provided.
Input the pressure control signal M2 from the low value selector 12,
The signal obtained by selecting the smaller signal by the low value selector 12 becomes the steam control valve flow rate command signal M3.

In this case, since the turbine inlet pressure constant control is performed in normal operation, the output setting signal M1 is set to a value slightly higher than the pressure control signal M2, and the pressure control signal M2 becomes the steam control valve flow rate command signal. It is set to M3. This steam control valve flow rate command signal M3 is input to the controller 13 to correct that the opening and flow rate characteristics of the steam control valve 5 are non-linear so that the steam control valve 5 is driven. The signal M4 of is output.

Further, in the adder 14, the steam control valve flow rate command signal M3 is subtracted from the pressure control signal M2, and the turbine bypass valve flow rate command signal M5 is input to the controller 15.
In the controller 15, the non-linearity of the opening degree and the flow rate characteristic of the turbine bypass valve 9 is corrected to be a straight line, and
A signal M6 for driving the turbine bypass valve 9 is output.

On the other hand, in the electric pressure control device 1, the actual pressure signal P1 from the pressure detector 16 which detects the turbine inlet pressure, converts it into an electric signal and outputs it, and the pressure setting device 17 which sets the turbine inlet pressure. The pressure setting signal P2 and the adder 18 are input to output the pressure deviation signal P3. The pressure deviation signal P3 is input to the pressure regulation rate setting device 19, and the steam flow rate command signal E1 for keeping the turbine inlet pressure constant is output from the pressure regulation rate setting device 19 to the adder 22.

In the adder 22, the steam flow command signal E1, the electric steam control valve flow signal E2, and the electric turbine bypass valve flow signal E3 are input and added or subtracted.
The deviation signal E4 added and subtracted by the adder 22 is input to the adjuster 23. The electric system steam control valve flow rate signal E2 is converted from the mechanical system steam control valve flow rate command signal M3 by the position detector 20. Further, the electric system turbine bypass valve flow rate signal E3 is converted from the mechanical system pressure control command signal E5 by the position detector 21.

The regulator 23 sets a constant for stably controlling the turbine inlet pressure, for example, a proportional constant, an integral constant, a differential constant, etc., and outputs a pressure control command signal E5.
Then, this signal is input to the electric / mechanical converter 11 to convert an electric system signal into a mechanical system signal and output a pressure control signal M2 for signal calculation in the mechanical turbine control device 2. The low value selector 12 selects the lower one of the output setting signal M1 and the pressure control signal M2, and outputs it to the controller 13 as a steam control valve flow rate command signal M3.
The steam control valve 5 from the steam control valve drive signal M4 from 3
Is controlled.

[0011]

However, in the above-described conventional steam turbine inlet pressure control device, the steam turbine control on the downstream side of the pressure control signal M2 is constituted by the mechanical system, and therefore the following problems are encountered in controlling the pressure. There is.

First, since the steam turbine inlet pressure control device is constituted by a mechanical system, non-linearity such as backlash and hysteresis peculiar to the mechanical system and delay in transmission occur, and the controller 13 and the regulator are adjusted. The device 15 corrects the flow rate command signal so that the actual amount of steam passing through the control valve changes linearly, but it is difficult to completely correct it. .

Secondly, the elements that are obstacles to the control by the mechanical system have the following characteristics because the steam control valve control system and the turbine bypass valve control system have different characteristics. That is, generally, the adjustment of the control constant of the adjuster 23 of the electric pressure control device 1 is performed mainly by the characteristics of the steam control valve control system in the normal operating state.
When the steam control valve 5 which is not in the normal operation state is fully closed and only the turbine bypass valve 9 is opened for pressure control, or when both the steam control valve 5 and the turbine bypass valve 9 are opened for pressure control, There is a problem that control becomes unstable. In this case, the steam control valve 5 and the turbine bypass valve 9
In order to achieve stable control under any condition, it is necessary to change the gain of the control constant according to each system.If the control gain is not adjusted, the control accuracy of the corresponding control system will decrease. However, there is a problem that the responsiveness becomes poor.

Therefore, the present invention stabilizes the pressure control of the steam turbine regardless of the opened / closed state of the steam control valve and the turbine bypass valve, and further, the steam turbine inlet pressure control for improving the deterioration of the control accuracy and the responsiveness. The purpose is to provide a device.

[0015]

According to the present invention, a pressure control command signal is calculated based on a deviation signal between a steam turbine inlet pressure setting signal and an actual pressure signal, and a steam control valve flow rate command signal is calculated from this pressure control command signal. And a turbine bypass valve flow rate command signal, a deviation signal is input to the controller, and an electric pressure control device that is composed of an electrical system that outputs a steam flow rate command signal, and a mechanical steam that is converted from the steam flow rate command signal. A mechanical turbine control device configured by a mechanical system that adjusts the opening degree of a steam control valve by a control valve flow rate command signal, and a mechanical system that controls the opening degree of a turbine bypass valve by a mechanical system turbine bypass valve flow rate command signal, and this machine. Of the mechanical steam control valve flow rate command signal and the mechanical system turbine bypass valve flow rate command signal of the electric turbine controller In a steam turbine inlet pressure control device consisting of a position detector that converts a reduction valve flow rate command signal and a turbine bypass valve flow rate command signal, the control constant of the regulator is preset in accordance with the opening / closing state of the steam control valve and turbine bypass valve. Means for switching to a set control constant, and a first function unit for correcting the steam control valve flow rate command signal converted from the mechanical system steam control valve flow rate command signal to an actual flow rate value passing through the steam control valve And a second function unit for correcting the turbine bypass valve flow rate command signal converted from the mechanical steam turbine bypass valve flow rate command signal to an actual flow rate value passing through the turbine bypass valve. .

[0016]

With the above configuration, the control constant of the regulator is in each state when only the steam control valve is open, only when the turbine bypass valve is open, and when both the steam control valve and the turbine bypass valve are open. The control constant is switched in accordance with the above, and the pressure is adjusted to the optimum control constant according to each state. Further, since the steam control valve flow rate command signal and the turbine bypass valve flow rate command signal become substantially equal to the actual steam flow rate by the function unit, unnecessary fluctuation does not occur in the pressure control signal output from the regulator of the electric pressure control device. Therefore, the pressure control becomes stable.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a steam turbine inlet pressure control device showing an embodiment of the present invention. The same reference numerals as those in FIG. 4 indicate the same or corresponding portions. 1 is different from FIG. 4 in that the setters 24a, 24 are provided in the electric pressure control device 1.
b, 24c, contact points 25a, 25b, 25c, and function unit 26
And the function unit 27 are additionally provided.

The setter 24a sets a control constant in the regulator 23 via a contact 25a which is closed when only the steam control valve 5 is open. The setter 24b has a contact 25 that is closed when only the turbine bypass valve 9 is open.
The control constant of the adjuster 23 is set via b. The setter 24c sets a control constant via a contact 25c that is closed when both the steam control valve 5 and the turbine bypass valve 9 are open. The function unit 26 inputs the steam control valve flow rate signal E2 and outputs a steam control valve flow rate corrected signal E8 to the adder 22 so as to obtain an actual steam flow rate value. The function unit 27 inputs the turbine bypass valve flow rate signal E3 and outputs the turbine bypass valve flow rate corrected signal E9 to the adder 22 so that the actual steam flow rate value passing through the turbine bypass valve 9 is obtained.

In the above structure, when only the steam control valve 5 is open, the contact 25a is closed by the steam control valve open signal, and the contacts 25b and 25c are open. In the electric pressure control device 1, the actual pressure signal P1 from the pressure detector 16 and the pressure setting signal P2 from the pressure setter 17 are input to the adder 18, and the pressure deviation signal P3 is set from the adder 18 to the pressure regulation rate setting. It is output to the device 19. Adder 22
Then, the steam flow rate command signal E1 of the pressure regulation rate setting device 19, the steam adjustment valve flow rate corrected signal E8, and the turbine bypass valve flow rate corrected signal E9 are input, and the added / subtracted deviation signal E4 is output to the adjuster 23. To be done.

In this case, the steam control valve flow rate corrected signal E8
Is, for example, as shown in FIG.
Is set in the function unit 26 so as to output the steam-controlled valve flow rate corrected signal E8 obtained by measuring in advance so as to become the actual steam flow rate value, and the steam control valve is controlled according to the steam control valve flow rate signal E2. The corrected flow rate signal E8 is output to the adder 22. As a result, the deviation signal E4 is input to the adjuster 23 such that the actual steam flow rate is obtained.

In the setter 24a, a control constant for performing optimum control when only the steam control valve 5 is opened is previously obtained and set, and this control constant is set in the adjuster 23. The output of the regulator 23 is electric / electrical as a pressure control command signal E5.
It is input to the mechanical converter 11. Then, the pressure control signal M2 output from the electric / mechanical converter 11 is selected by the low value selector 12 and becomes the steam control valve flow rate command signal M3. As a result, the steam control valve 5 is opened and closed by the steam control valve drive signal M4 via the controller 13.

Further, when only the turbine bypass valve 9 is open, for example, as shown in FIG. 3, the actual steam flow rate value passing through the turbine bypass valve 9 is set in advance for the turbine bypass valve flow rate signal E3. The function unit 27 is set to output the measured turbine bypass valve flow rate corrected signal E9. As a result, the turbine bypass valve flow rate corrected signal E9 is output to the adder 22 according to the turbine bypass valve flow rate signal E3. Therefore, the deviation signal E4 is input to the regulator 23 so that the deviation signal E4 becomes the actual steam flow rate.

In the setter 24b, the turbine bypass valve 9
A control constant for performing optimum control when only one is open is obtained and set in advance, and this control constant is set in the adjuster 23. As a result, the output of the regulator 23 is input to the electromechanical converter 11 as the pressure control command signal E5. In this case, in the low value selector 12, zero of the output setting signal M1 is selected and the steam control valve 5 is closed, and the pressure control signal M2 of the electric / mechanical converter 11 is adjusted as the turbine bypass valve flow rate command signal M5. 15 is input. This allows
The turbine bypass valve 9 is opened / closed via the adjuster 15.

Further, when both the steam control valve 5 and the turbine bypass valve 9 are open, the contact 25c determines in advance a control constant for optimum control when both the steam control valve 5 and the turbine bypass valve 9 are open. The control constant is set in the adjuster 23. As a result, the output of the regulator 23 is output as the pressure control command signal E5 in the electromechanical converter 1
Input to 1. In this case, the low value selector 12 selects the output setting signal M1 of the speed output setter 10, and the steam control valve flow rate command signal M3 is transmitted via the controller 13 to the steam control valve 5.
Control the opening and closing of. On the other hand, the pressure control signal M in the adder 14
2 and the difference between the steam control valve flow rate command signal M3 is obtained,
This deviation is used as a turbine bypass valve flow rate command signal M5 to control the opening / closing of the turbine bypass valve 9 via the controller 15.

The function unit 26 shown in FIG. 2 and FIG.
And the function of the function unit 27 is determined by the flow rate characteristic of the valve,
Collect the data in advance and set the optimum one. In general, when there are a plurality of valves and the plurality of valves are sequentially opened, the flow rate characteristic of the valve becomes non-linear at the beginning of opening of the valve or the position where the valve is fully opened. In addition, the setters 24a, 24b, 24c
The signals for operating the contact points 25a, 25b, 25c of are the signals of the drive parts of the steam control valve 5 and the turbine bypass valve 9, but the steam control valve flow signal E2 of the position detector 20 and the turbine bypass of the position detector 21 are used. It may be detected from the valve flow rate signal E3.

Thus, when only the steam control valve 5 is open, when only the turbine bypass valve 9 is open,
Since the control constant of the regulator 23 can be set to an optimum value according to each state when both the steam control valve 5 and the turbine bypass valve 9 are open, the optimum pressure control command signal E is always obtained.
5 is output.

Further, since the steam control valve and turbine bypass valve flow rate signals returned from the mechanical turbine control device become equal to the actual steam flow rate signal by the signal correction by the function unit 26 and the function unit 27, the pressure control command signal E5. Change and the actual steam flow rates of the steam control valve and the turbine bypass valve change, and the sum of the change amount of the steam flow rate command signal E1 and the steam control valve flow rate corrected signal E8 and the turbine bypass valve flow rate corrected signal E9. , The deviation of the deviation signal E4 is reduced, and the unnecessary fluctuation of the pressure control command signal E5 output from the adjuster 23 is reduced, so that the entire control system is stabilized.

Therefore, since the optimum control constant can be set according to the states of the steam control valve and the turbine bypass valve, stable pressure control is always possible, and the steam control valve and the turbine bypass valve of the mechanical turbine control device can be controlled. Even if the characteristic of the regulator is a non-linear characteristic, since the correction is made according to the actual steam flow rate characteristic of the control valve, it is possible to obtain the effect of stabilizing the entire control.

In the embodiment of the present invention, a plurality of setters for setting the control constants are provided for one regulator, and the setters are switched according to the open / closed state of the control valve. , The same effect can be obtained by switching the pressure control command signal according to the open / closed state of the control valve by providing a plurality of regulators whose control constants are set so that the optimum pressure control is performed according to the open / closed state of the control valve. It is possible to obtain.

[0031]

As described above, according to the present invention, since the optimum control constant can be adjusted according to the opening / closing state of the steam control valve and the turbine bypass valve, stable pressure control is always possible, In addition, control accuracy and responsiveness can be improved. In addition, since the steam control valve flow rate signal and turbine bypass valve flow rate signal become equal to the actual steam flow rate by the function unit, there is no unnecessary change in the pressure control command signal output from the regulator, and pressure control is stable. Becomes

[Brief description of drawings]

FIG. 1 is a configuration diagram of a steam turbine inlet pressure control device showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a function unit for correcting the flow rate characteristic of the steam control valve of FIG.

FIG. 3 is an explanatory diagram showing an example of a function unit for correcting the flow rate characteristic of the turbine bypass valve of FIG.

FIG. 4 is a configuration diagram of a conventional steam turbine inlet pressure control device.

[Explanation of symbols]

 1 Electric Pressure Control Device 2 Mechanical Turbine Control Device 3 Steam Generator 4 Main Steam Stop Valve 5 Steam Control Valve 9 Turbine Bypass Valve 10 Speed Output Setting Device 11 Electric / Mechanical Converter 12 Low Value Selector 13 Regulator 14 Addition 15 regulator 16 pressure detector 17 pressure setter 18 adder 19 pressure regulation rate setter 20 position detector 21 position detector 23 regulator 24a, 24b, 24c setter 25a, 25b, 25c contact 26 function unit 27 function vessel

Claims (1)

[Claims] 1. A pressure control command signal is calculated based on a deviation signal between a steam turbine inlet pressure setting signal and an actual pressure signal, and a steam control valve flow rate command signal and a turbine bypass valve flow rate command signal are calculated from this pressure control command signal. The electric pressure control device that is composed of an electric system in which the regulator that inputs the deviation signal that subtracts is a steam flow rate command signal, and the steam by the mechanical system steam control valve flow rate command signal converted from the steam flow rate command signal A mechanical turbine control device configured by a mechanical system that adjusts the opening degree of the control valve and also adjusts the opening degree of the turbine bypass valve by a mechanical system turbine bypass valve flow rate command signal, and the machine of the mechanical turbine control device. System steam control valve flow rate command signal and the mechanical system turbine bypass valve flow rate command signal are returned to return the steam control valve of each of the electric pressure control devices. In a steam turbine inlet pressure control device including a position detector that converts a flow rate command signal and the turbine bypass valve flow rate command signal, a control constant of the regulator according to the open / close state of the steam control valve and the turbine bypass valve. Means for switching to a preset control constant, and a correction for making the steam control valve flow rate command signal converted from the mechanical system steam control valve flow rate command signal an actual flow rate value passing through the steam control valve And a second function unit for correcting the turbine bypass valve flow rate command signal converted from the mechanical steam turbine bypass valve flow rate command signal to an actual flow rate value passing through the turbine bypass valve. A steam turbine inlet pressure control device comprising: