JPH0821203A - Pressure controller - Google Patents

Abstract

PURPOSE:To provide a pressure controller by which switching of two types of pressure detectors can be smoothly performed. CONSTITUTION:Two types of steam pressure detectors having different measuring ranges of narrow ranges and wide ranges, a bias generator 26 for generating the specific bias, and switching devices 32, 27, 28 for selectively outputting a bias signal output from the bias generator 26 into a narrow range side change rate limiter 29 or a wide range side change rate limiter 30 are provided. Moreover, a pressure controller is provided with a narrow range side adder 24 and a wide range side adder 25 for respectively adding output signals from both change rate limiters 29, 30 to the pressure signal detected by the detector, and a high value preceding circuit 31 for outputting a high value signal out of signal outputs from both adders as the pressure signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure control device for controlling a reactor dome pressure or a turbine inlet steam pressure in a nuclear power plant.

[0002]

2. Description of the Related Art FIG. 8 is a diagram showing a steam system of a typical nuclear power plant, in which steam generated in a nuclear reactor 1 is supplied to a steam turbine 3 after being adjusted by a steam control valve 2. The steam used for the work is condensed in the condenser 4 and the generator 5 directly connected to it by the steam turbine 3.
Is driven to generate electricity.

On the other hand, a bypass conduit 7 having a turbine bypass valve 6 is branched from the upstream side of the steam control valve 2, and during normal operation, the turbine bypass valve 6 is fully closed and the pressure of the reactor 1 is reduced. Is adjusted by the steam control valve 2, and the pressure of the reactor 1 is adjusted by the turbine bypass valve 6 at the time of plant start / stop or system failure.

By the way, FIG. 9 is a block diagram of a control system of the steam control valve 2 and the turbine bypass valve 6, and a pressure detector 1 installed at a turbine inlet or a reactor.
The pressure of 0 is input to the pressure control device 11, and the pressure setter 1
The pressure set value of 2 is compared and calculated by the deviation calculator 13 and input to the pressure regulation rate circuit 14. This pressure regulation rate circuit 14
The deviation signal multiplied by the pressure regulation rate is input to the low value selection circuit 15 as the total steam flow rate command signal.

In the low value selection circuit 15, the total steam flow rate command signal is compared with the signal from the load control device 16, and the low value signal is output as the steam control valve opening degree command signal. Further, the deviation between the total steam flow rate command signal output from the pressure regulation rate circuit 14 and the steam control valve opening command signal is calculated by the deviation calculator 17, and the deviation signal is output as the turbine bypass valve opening command signal. .

The pressure detector 10 is often multiplexed by using a plurality of detectors in order to improve reliability, but it is described here as one for simplicity.

[0007]

In recent plants, in order to reduce the burden on operators, automation of start / stop operations of the plant has been introduced, and it is required to control the reactor pressure to a lower pressure. In response to this, it has become necessary to expand the pressure detection range by the pressure detector.

However, when a pressure detector having a wide detection range is simply applied, there is a problem that required accuracy cannot be obtained in the load control range. Therefore, it is necessary to use a narrow band pressure detector having high accuracy at least in the load control range and a wide band pressure detector having an expanded detection range in combination.

However, when two types of detectors are used as described above, it is necessary to switch signals.
There is a problem in that a pressure disturbance occurs due to a detection deviation between the two types of detectors when the signal is switched.

In view of the above points, the present invention has an object to obtain a pressure control device which can smoothly switch between two types of pressure detectors.

[0011]

SUMMARY OF THE INVENTION The present invention comprises two types of vapor pressure detectors having different measurement ranges, a narrow band and a wide band,
A bias generator that generates a predetermined bias, a switching device that selectively outputs the bias signal output from the bias generator to the narrow band side change rate limiter or the wide band side change rate limiter, and the narrow band Narrowband side arithmetic unit and wideband side arithmetic unit for directly or indirectly adding or subtracting the output signals from the side change rate limiter and the wideband side change rate limiter to the pressure signals detected by the corresponding steam pressure detectors, respectively. And a selection circuit for outputting a signal whose bias is not added or subtracted by the arithmetic unit as a pressure signal.

According to a second aspect of the present invention, the switching device has a narrow band side contact and a wide band side contact which are arranged between the bias generator and both rate-of-change limiters, and a switch for turning on and off both the contacts. Circuit and its switching circuit turns on the wide band side contact and turns off the narrow band side contact when the pressure is within the detection range of the narrow band pressure detector, and turns off the wide band side contact in other cases. However, the narrow band side contact is turned on.

Further, in a third invention, the switching device is
It has a narrow band side contact and a wide band side contact which are arranged between the bias generator and both rate-of-change limiters, and a switching circuit which turns on and off both of the contacts, and the switching circuit has a narrow band pressure. The narrow band side contact is turned off when it is within the detection range of the detector, and the wide band side contact is turned on when the narrow band side bias is 0, and the pressure is outside the detection range of the narrow band pressure detector. It is characterized in that the wide band side contact is turned off when it is turned on, and the narrow band side contact is turned on when the wide band side bias becomes zero.

According to a fourth aspect of the present invention, the output signals from the narrow band side rate-of-change limiter and the wide band side rate-of-change limiter are respectively added to the pressure setting signals from the pressure setting unit, and the added signals correspond to the vapors respectively. It is characterized in that it is subtracted from the pressure signal detected by the pressure detector.

A fifth aspect of the invention is to provide a comparator in place of the high-value priority circuit so that when the deviation between the outputs of the narrow band side arithmetic unit and the wide band side arithmetic unit becomes 0, the narrow band side and the wide band side are It is characterized by performing signal switching.

[0016]

For example, when the pressure at the inlet of the steam turbine falls within the detection range of the narrow band pressure detector, the switching device operates and the bias signal is added to or subtracted from the pressure signal detected by the wide band pressure detector to obtain the wide band. The signal output from the side adder becomes small, and the pressure signal from the narrow band pressure detector, which is a high value signal, is output as a control signal from the high value priority circuit. Therefore, switching can be performed according to the detection range of the narrow band detector and the wide band detector. Moreover, by providing the change rate limiter in the bias circuit, it is possible to smoothly switch signals between the narrow band pressure detector and the wide band pressure detector.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the figure, the same parts as those in FIG.

FIG. 1 is a block diagram of a pressure control device of the present invention. Reference numerals 20a, 20b and 20c are narrow band pressure detectors, and the narrow band pressure detectors 20a, 20b,
The pressure signal detected by 20c is input to the intermediate value selection circuit 21, where the intermediate value or average value of the pressure signal is output as the narrow band pressure detection signal a. Similarly, the pressure signals detected by the broadband pressure detectors 22a, 22b, 22c are also input to the intermediate value selection circuit 23, where the intermediate value or average value of the pressure signals is output as the broadband pressure detection signal b, The narrow band pressure detection signal a and the wide band pressure detection signal b are input to the narrow band side adder 24 and the wide band side adder 25, respectively.

On the other hand, reference numeral 26 in the figure denotes a bias generator, and the negative bias signal generated from the bias generator 26 is passed through the narrow band side contact 27 or the wide band side contact 28, respectively, and the narrow band side change rate. The limiter 29 or the wide band side change rate limiter 30 is input. The output signals c and d from the narrow band side change rate limiter 29 and the wide band side change rate limiter 30 are input to the narrow band side adder 24 or the wide band side adder 25, respectively, and the outputs from both adders are output. The signals are respectively input to the high value priority circuit 31 constituting the selection circuit, and the high value signal of the input signal is compared and calculated by the deviation calculator 13 with the pressure set value of the pressure setter 12.

By the way, the change rate limiters 29, 30
Is for limiting the rate of change of the output signal when the input signal changes, to a predetermined rate or less.
The switching circuit 32 switches the 7 and the broadband contact 28.

FIG. 2 is a diagram showing the configuration of the switching circuit 32. The switching circuit 32 is provided with first and second comparators 33 and 34, and both comparators 33 and 34 are provided.
A narrow band pressure detection signal a is input to. The first
The comparator 33 of FIG. 3 outputs when the narrow band pressure detection signal a is above a predetermined set pressure, and the second comparator 34 outputs when it is below another set pressure higher than the set pressure. The output signals from the devices 33 and 34 are AND circuits 3
5 is input.

However, when the narrow band detection signal a is within the set pressure range, a control signal is output from the AND circuit 35, the wide band side contact 28 is turned on, and the narrow band side contact 2
7 is turned off. When the narrow band pressure detection signal a is out of the set pressure range and no output signal is generated from the AND circuit 35, the control signal is output via the inverter 36, the wide band side contact 28 is turned off, and the narrow band side contact 28 is turned off. The band side contact 27 is turned on. That is, when the pressure at the inlet of the steam turbine is within the detection range of the narrow band pressure detector, the control signal is output from the AND circuit 35 as described above, the contact 28 is turned on, and the contact 27 is turned off. . Therefore, the negative bias signal generated from the bias generator 26 is input to the wide band side change rate limiter 30, and the negative bias signal is gradually widened at a constant rate via the wide band side change rate limiter 30. Wideband pressure detection signal b in the side adder 25
And the bias signal output from the narrow band side change rate limiter 29 gradually decreases toward 0.

Therefore, the signal f on the wide band side has a lower value than the signal g on the narrow band side, and the signal g on the narrow band side is input to the deviation calculator 13 as the pressure signal h in the high value priority circuit 31, and there. It is compared with the pressure set value of the pressure setter 12, and its deviation signal is output as a total steam flow rate command signal.

On the other hand, when the pressure is outside the detection range of the narrow band pressure detector, the contact 27 is turned on and the contact 28 is turned off. Therefore, a negative bias signal that gradually increases at a constant rate via the narrow band side change rate limiter 29 is added to the narrow band pressure detection signal a, and from the high value priority circuit 31,
The broadband side pressure signal f is output as the pressure signal h.

That is, FIG. 3 is a diagram showing the switching state of the pressure signal. Assuming that the pressure is within the detection range of the narrow band pressure detector at time tx, according to the set ratios of the change rate limiters 29 and 30. , The signal f on the wide band side decreases and the signal g on the narrow band side increases, and the pressure signal h switches from the signal f on the wide band side to the signal g on the narrow band side.

In this way, it is possible to switch between using a high-precision narrow band pressure detector in the load control range and using a wide band pressure detector in other ranges, and switching between the two is performed smoothly. be able to.

FIG. 4 is a diagram showing another embodiment of the switching circuit 32. The switching circuit 32 includes a first comparator 33 and a second comparator 33.
In addition to the comparator 34, the third comparator 37 that detects that the narrow band side bias c is 0 and the fourth comparator 38 that detects that the wide band side bias d is 0 are provided. There is. The output signals of the first comparator 33 and the second comparator 34 are input to the AND circuit 35, and the contact 27 is turned off when the AND condition of both is satisfied. Further, the AND circuit 35 and the third
The output signal from the comparator 37 is also input to the AND circuit 39, and the contact 28 is turned on when the AND condition of both is satisfied.

Further, the AN in the AND circuit 35.
When the D condition is not satisfied, a control signal for turning off the contact 28 is output to the contact 28 via the inverter 36, and output signals from the inverter 36 and the fourth comparator 38 are output. Both are input to the AND circuit 40, and the contact 27 is turned on when the AND condition of both is satisfied.

However, when the pressure is within the detection range of the wide band side pressure detector, the contact point 28 is in the off state and the contact point 27 is in the on state, and the high value priority is given by adding a negative bias signal to the narrow band side pressure signal a. In the circuit 31, the broadband signal f is output as the pressure signal h.

In this state, when it is detected by the comparators 33 and 34 that the control range of the narrow band side pressure detector is detected at the time tx, the contact 27 is generated by the signal from the AND circuit 35.
Is turned off. Therefore, the negative bias signal added to the narrow band side pressure signal a gradually changes toward 0 via the narrow band side change rate limiter 29. Therefore, when the third comparator 37 detects that the bias on the narrow band side is 0 within the control range of the narrow band side pressure detector, the AND condition of the AND circuit 39 is established, and the contact is established. 28 is turned on, a negative bias is applied to the wide band pressure signal b via the wide band side change rate limiter 30, and the high band priority circuit 31 outputs the narrow band side signal g as the pressure signal h. This switching operation status is shown in FIG.

Also in the switching operation from the narrow band side to the wide band side, when it is detected that the contact 28 is turned off and the wide band side bias d becomes 0 by the operation of the inverter 36, the AND circuit is detected. AND condition of 40 is satisfied,
The contact 27 is switched to the ON state, and continuous switching operation is performed.

FIG. 6 is a diagram showing another embodiment of the pressure control device of the present invention, in which output signals from the narrow band side rate-of-change limiter 29 and the wide band side rate-of-change limiter 30 are respectively added to the narrow band side. Is added to the pressure set value e of the pressure setting device 12 in the device 24 and the wide band side adder 25, and the addition signals are input to the narrow band side deviation calculator 41 and the wide band side deviation calculator 42, respectively.

In the narrow band side deviation calculator 41, the addition signal output from the narrow band side adder 24 is compared with the narrow band side pressure signal a, and the deviation signal is compared with the narrow band side pressure regulation ratio circuit 43. Is input to the high price priority circuit 31 via. In addition, in the wideband side deviation calculator 42, the addition signal output from the wideband side adder 25 is the wideband side pressure signal b.
And the deviation signal is compared with the pressure regulation rate circuit 4 on the wideband side.
It is inputted to the high price priority circuit 31 via the No. 4. Then, the low value signal of the pressure signal output from the high value priority circuit 31 and the control signal from the load control device 16 is selected and output as the opening command signal to the steam control valve, and the pressure signal h A deviation signal from the steam control valve opening command signal is output as a turbine bypass valve opening command signal.

When the pressure reaches the detection range of the narrow band side pressure detector, the switching circuit 32 causes the contacts 27, 28 to come into contact.
Is switched on, the contact 28 is turned on, and the contact 27 is turned off. Therefore, the positive bias signal generated from the bias generator 26 passes through the contact point 28 and the wide band side change rate limiter 30 and gradually increases at a constant rate.
And the added signal is subtracted from the wideband side pressure signal b by the wideband side deviation calculator 42. On the other hand, in the narrow band side change rate limiter 29, the bias signal is gradually reduced to 0 at a constant rate. Therefore, the high price priority circuit 3
The pressure signal g on the narrow band side entering 1 becomes large, and the high band priority circuit 31 outputs the narrow band side pressure signal g as a pressure signal.

When the pressure is outside the detection range of the narrow band pressure detector, the narrow band side adder 24 adds a positive bias to the pressure set value e and subtracts the narrow band side pressure signal a. It Therefore, the high-value priority circuit 31 outputs the wideband side pressure signal f as the pressure signal h, and has the same effect as the first embodiment.

FIG. 7 is a diagram showing another embodiment of the pressure control device shown in FIG. 6, in which a pressure regulation rate circuit 14 is provided on the downstream side of the high price priority circuit 31, and the pressure regulation rate on the narrow band side is provided. The circuit 43 and the wide band side pressure regulation rate circuit 44 are deleted. In this case, however, it is not necessary to divide the pressure regulation rate circuit into two types, one for a wide band and the other for a narrow band.

[0037]

As described above, according to the present invention, the bias signal is selectively added or subtracted by the switching device to the signals detected from the narrow band side pressure detector and the wide band side pressure detector, and the high value signal thereof is obtained. Is selected as the pressure signal, the high-precision narrow-band side pressure detector is used in the load control range, and the wide-band side pressure detector is used in the other ranges, switching according to the detection range. Further, by providing the change rate limiter in the bias circuit, the switching of the detector can be smoothly performed only by switching the bias signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a pressure control device of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a switching circuit in the pressure control device of the present invention.

FIG. 3 is an operation explanatory view of an apparatus using the switching circuit of FIG.

FIG. 4 is a diagram showing another embodiment of the switching circuit in the pressure control device of the present invention.

FIG. 5 is an operation explanatory view of an apparatus using the switching circuit of FIG.

FIG. 6 is a diagram showing another embodiment of the pressure control device of the present invention.

FIG. 7 is a diagram showing still another embodiment of the pressure control device of the present invention.

FIG. 8 is a steam diagram of a typical nuclear power plant.

FIG. 9 is a diagram showing a schematic configuration of a conventional pressure control device.

[Explanation of symbols]

 12 Pressure setter 13 Deviation calculator 14 Pressure regulation rate circuit 15 Low value selection circuit 24 Narrow band side adder 25 Wide band side adder 26 Bias generator 27 Narrow band side contact 28 Wide band side contact 31 High value priority circuit 32 Switching circuit 33 1st comparator 34 2nd comparator 36 Inverter 37 3rd comparator 38 4th comparator 41 Narrow band side deviation calculator 42 Wide band side deviation calculator

Claims (7)

[Claims] 1. A narrow band side and a wide band, two kinds of vapor pressure detectors having different measurement ranges from each other, a bias generator for generating a predetermined bias, and a bias signal output from the bias generator. A switching device that selectively outputs to the change rate limiter or the wide band side change rate limiter, and the output signals from the narrow band side change rate limiter and the wide band side change rate limiter are detected by the corresponding vapor pressure detectors. A narrow-band side arithmetic unit and a wide-band side arithmetic unit for directly or indirectly adding or subtracting to or from the generated pressure signal, and a selection circuit for outputting a signal whose bias is not added or subtracted by the arithmetic unit as a pressure signal. A pressure control device characterized by the above. 2. The switching device includes a narrow band side contact and a wide band side contact arranged between a bias generator and both rate-of-change limiters, and a switching circuit for turning on and off both the contacts. When the pressure is within the detection range of the narrow band pressure detector, the switching circuit turns on the wide band side contact and turns off the narrow band side contact, and otherwise turns off the wide band side contact and narrow band side contact. The pressure control device according to claim 1, wherein the pressure control device is turned on. 3. The switching device includes a narrow band side contact and a wide band side contact arranged between a bias generator and both rate-of-change limiters, and a switching circuit for turning on and off the both contacts. The switching circuit turns off the narrow-band side contact when the pressure falls within the detection range of the narrow-band pressure detector, and turns on the wide-band side contact when the narrow-band side bias becomes 0, so that the pressure becomes narrow. 2. The pressure control device according to claim 1, wherein the wide band side contact is turned off when the band pressure detector is out of the detection range, and the narrow band side contact is turned on when the wide band side bias becomes 0. . 4. The output signals from the narrow band side rate-of-change limiter and the wide band side rate-of-change limiter are respectively added to the pressure setting signals from the pressure setter, and the added signals are respectively sent to the corresponding vapor pressure detectors. The pressure control device according to claim 1, wherein the pressure control device is subtracted from the detected pressure signal. 5. The pressure regulation rate circuit is provided between each of the narrow band side adder and the wide band side adder and the high value priority circuit, according to any one of claims 1 to 4. Pressure control device. 6. The pressure control device according to claim 1, further comprising a pressure regulation rate circuit provided downstream of the high price priority circuit. 7. A comparator is provided instead of the high value priority circuit, and when the deviation between the outputs of the narrowband side adder and the wideband side adder becomes 0, the narrowband side and wideband side signals are switched. The pressure control device according to any one of claims 1 to 6, which is characterized.