JPS6380005A - Turbine control device of nuclear power plant - Google Patents

Abstract

PURPOSE:To restrain the pressure of a nuclear reactor from changing at the time of a load change in an electric power system by controlling a turbine by-pass valve opening degree based on a governor valve opening degree signal and a load demand signal. CONSTITUTION:A load demand signal S9 is formed by adding an output signal S71 of a speed controller 13 to a load set signal S8, and a modified load demand signal S13 of a governor valve 2 from the load demand signal S9. This demand signal S12 is inputted into a low value selective circuit 14 together with a total steam flow demand signal S4 which is the output of a pressure controller 12. Based on the output of a governor valve opening degree demand signal S14, the total steam flow demand signal S4 and a chattering prevention bias signal B2, a by-pass valve 6alpha opening degree demand signal S15 is computed and inputted into a by-pass valve servo 16.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a turbine control device for a nuclear power plant, and is particularly suitable for suppressing reactor pressure fluctuations and reactor water level fluctuations in a boiling water reactor. The present invention relates to a turbine control device.

[Conventional technology]

As a turbine control device for a nuclear power plant, an example of the relationship control of a turbine steam control valve and a turbine bypass valve in the event of an accident in an electric power system is disclosed in Japanese Patent Application Laid-Open No. 61-58903.
"Nuclear Reactor Turbine Control Device".

That is, the steam generated in the reactor 1 in FIG.
is guided to the turbine 3 via the turbine steam control valve 2,
The turbine 3 is rotated, thereby generating electrical energy in the generator 7. The steam that rotates the turbine 3 turns into water in the condenser 4 and is returned to the reactor 1 by the water pump 5. The turbine bypass valve 6 has a function of discharging surplus steam from the nuclear reactor 1 when suppressing frequency fluctuations due to load fluctuations in the electric power system 8 to which the generator 7 is connected. In addition, reactor 1 due to abnormality in reactor 1 or power system 8
It has functions such as suppressing the pressure rise of

A pressure deviation signal S3, which is a deviation signal between the reactor pressure signal S1 detected by the pressure detector 11 and the set pressure signal S2, is
This becomes an input signal for the pressure controller 12. The pressure controller 12 is
By calculation according to pressure adjustment rate and lead/lag compensation,
A total steam flow rate request signal S4 is output. On the other hand, a speed deviation signal S7, which is a deviation signal between the turbine speed signal S5 and the set speed signal S6, becomes an input signal to the speed controller 13.

The speed controller 13 outputs a speed controller output signal 871 by calculation according to the speed regulation rate. The total steam flow rate request signal S4 and the load request signal S9 obtained by adding the load setting signal S8 to the speed controller output signal S71 are compared by the low value selection circuit 14, and the signal indicating the lower value is selected as the control valve opening request signal. It is output as S14. Normally, load setting signal S8
is higher than the total steam flow rate request signal S4 by an amount equivalent to the load setting bias, so the low value selection circuit 14 selects the total steam flow rate request signal S4 and performs pressure priority control to keep the 1M slave furnace pressure constant. Further, the turbine control valve opening request signal 51
4, the total steam flow rate request signal S4, and the chattering prevention bias signal B2, a turbine bypass valve opening request signal 5151 is obtained.

Load request error signal S10 based on load request signal S9, total steam flow rate request signal S4, and load setting bias signal B2
is input to the recirculation flow rate control system 10, and the recirculation pump 9
control the rotation speed. Thereby, the core flow rate can be changed and the yX child reactor output can be controlled.

The turbine control valve opening request signal 514 becomes a control valve servo drive signal 5141 based on the deviation from the control valve opening signal 817, which is the output signal of the control valve opening detector 17, and is input to the control valve servo 15 to generate turbine steam. Controls the opening degree of the adjustment valve 2. Further, the corrected turbine bypass valve opening request signal S16 based on the total steam flow rate request signal S4, the regulating valve opening signal S17, and the bias signal B3 is an input signal of the high value selection circuit 18, together with the turbine bypass valve opening request signal S15. becomes. Normally, the turbine control valve opening request signal S14
Since and the adjustment valve opening signal 517 are equal, and since the bias signal B3 is set to be larger than the load setting bias signal B2, the high value selection circuit 18 selects the turbine bypass valve opening request signal S15, Bypass valve servo drive signal Controls the opening degree of the bin bypass valve 6.

When an accident such as a lightning strike occurs in the power system 8, the accident location is temporarily separated from the power system 8, and the operation is performed to connect it to the power system 8 again after the accident is restored. At this time, due to the load separation and connection of the power system 8, the turbine speed signal S5 increases by a certain amount, and then returns to the steady value after 2 to 3 seconds due to the accident recovery operation. Accordingly, when the load request signal S9 decreases to a value greater than or equal to the load setting bias signal of the load setting signal S8, the low value selection circuit 14 selects the load request signal S9 and outputs it as the turbine adjustment valve opening request signal 514. Here, if the change in the load request signal S9 is rapid, the adjustment valve servo 15 cannot follow it sufficiently due to its structural constraints, etc. Therefore, the adjustment valve opening signal 817 is Therefore, the turbine bypass valve opening request signal S15, which is the input signal of the high value selection circuit 18, and the corrected turbine bypass valve opening request signal S16 do not match.
That is, based on the input of the turbine bypass valve opening request signal S15 and the corrected turbine bypass valve opening request signal S16 accompanying the fluctuation of the load request signal S9, the high value selection circuit 18 outputs the bypass valve servo drive signal 5152. At this time, since the turbine bypass valve 6 has a faster response speed than the turbine steam control valve 2, it can sufficiently follow the bypass valve servo drive signal 5152.

Therefore, the bypass valve servo drive signal 5152 can be regarded as the opening degree of the turbine bypass valve 6.

By controlling the opening degrees of the turbine steam control valve 2 and the turbine bypass valve 6 in this manner, the opening of the turbine steam control valve 2 is controlled in response to an increase in the turbine speed signal S5 due to a decrease in load due to an accident in the power system 8. The flow rate of steam flowing into the turbine 3 is reduced by reducing the temperature. At the same time, the pressure of the turbine bypass valve 6 is increased to discharge excess steam from the reactor 1 to the condenser 4. In addition, in response to a decrease in the turbine speed signal S5 due to an increase in load due to accident recovery, the reduced opening degree of the turbine steam control valve 2 is increased, and the opening degree of the turbine bypass valve 6 is changed to the opening degree of the turbine steam control valve 2. decrease as the degree increases. Due to such cooperative opening control of the turbine steam control valve 2 and the turbine bypass valve 6, nuclear reactor 1 pressure rise can be suppressed. Furthermore, a significant increase in neutron flux due to reactor pressure fluctuations can also be suppressed.

In addition, regarding the control of the relationship between the turbine steam control valve and the turbine bypass valve during sudden changes in the load of the power system, JP-A No. 6
It is described in Publication No. 0-256098 [Nuclear Reactor Pressure Control Device]. In this example, if the rate of change in the opening and closing direction operations of the turbine bypass valve opening request signal exceeds the operating speed of the turbine steam control valve, the rate of change in the operation of the turbine bypass valve opening request signal is changed to The operation limiter limits the rate of change in operation of the turbine steam control valve.

[Problem that the invention seeks to solve]

The reactor turbine control device closes the turbine bypass valve in order to suppress the reactor pressure rise that occurs due to the difference in valve opening characteristics between the turbine steam control valve and the turbine bypass valve during an accident in the power system. For directional operation, valve opening control is performed to match the valve operating characteristics of the turbine steam control valve.

However, since there was no consideration given to the drop in reactor pressure based on the operation of the turbine bypass valve in the opening direction, there was a possibility of turbine tripping due to a rise in the reactor water level. Furthermore, since the valve opening controls of the turbine steam control valve and the turbine bypass valve are not perfectly coordinated, there is a problem in that the reactor pressure fluctuates and, furthermore, the neutron flux fluctuates.

Furthermore, the turbine bypass valve operation limiter of the reactor pressure control system has a complicated structure.

An object of the present invention is to suppress fluctuations in reactor pressure by controlling the opening and closing directions of the turbine bypass valve using the valve operating characteristics of the turbine steam control valve, thereby reducing neutron flux fluctuations and atomic An object of the present invention is to provide a turbine control device that suppresses fluctuations in reactor water level.

[Means for solving problems]

When rapid load fluctuations occur, such as an accident in the power system, the valve operation characteristics of the turbine steam control valve are used to control the opening degree of the turbine bypass valve in the opening and closing directions. A modified load request signal for controlling the opening of the turbine bypass valve is generated based on the adjustment valve opening signal of the valve and the load request signal which is an addition signal of the output signal of the turbine speed controller and the load setting signal. I adopted the means to obtain it.

[Effect]

The modified load request signal obtained based on the relationship signal of the turbine steam control valve and the load request signal which is the addition signal of the output signal of the turbine speed controller and the load setting signal is the turbine control valve opening request signal. If the adjustment valve opening signal matches, it is equal to the load request signal. If the turbine regulating valve opening request signal and the regulating valve opening signal do not match, they are made equal to the regulating valve opening' signal. As a result, when the turbine steam control valve opening request signal, which is the output of the low value selection circuit that receives the total steam flow rate request signal and the modified load request signal as input, selects the modified load request signal, the turbine bypass valve opening will be controlled by the operating characteristics of the turbine steam control valve.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to FIGS. 1 and 2.

The differences in FIG. 1 from the conventional example shown in FIG. 4 are as follows. That is, the speed controller output signal S71, which is the output signal of the speed controller 13, is the load setting signal S8.
is added to form the load request signal S9. Function generator 156
The deviation between the adjustment valve opening degree signal S13, which is an output signal from the controller 1, and the load request signal S9 becomes the adjustment valve opening degree deviation signal Sll. The deviation between the adjustment valve opening degree deviation signal Sll and the load request signal becomes the corrected load request signal 812. Low value selection circuit 1
4 inputs the corrected load request signal S12 and the total steam flow rate request signal S4 which is the output of the pressure controller 12, and outputs the turbine adjustment valve opening request signal S14. The turbine regulating valve opening request signal S14 is input to the regulating valve servo 15 via the function generator 155, and controls the opening of the turbine steam regulating valve 2. Further, a turbine bypass valve opening request signal S15 based on the total steam flow rate request signal S4, the turbine control valve opening request signal S14, and the chattering prevention bias signal B2 is input to the bypass valve servo 16, and the turbine bypass valve opening request signal S15 is inputted to the bypass valve servo 16, After the turbine control valve opening request signal S14, which is the output of the low value selection circuit 14 that controls the opening, is corrected by the function generator 155,
The deviation from the output signal 5131 of the piston position detector 154 is taken. This deviation signal is amplified by the control valve servo amplifier and transmitted to the control valve servo valve 152. The control valve servo valve 152 operates the piston of the control valve hydraulic cylinder 53 based on the amplified deviation signal. The turbine steam control valve 2 connected to the piston of the control valve hydraulic cylinder 53 opens and closes as the piston moves.

The output signal 5131 of the piston position detector 154 is corrected by the function generator 156 and becomes the adjustment valve opening signal S13. If the output signal 5131 of the piston position detector 154, which can be considered as a regulating valve opening detector, cannot be used due to restrictions such as the structure of the regulating valve servo 15, a separate opening detector of the turbine steam regulating valve 2 is provided. , by applying appropriate correction processing to the output signal of this adjustment valve opening degree detector.

It is used as the control valve signal S13.

In FIG. 1, when the low value selection circuit 14 selects the total steam flow rate request signal S4, which is the output of the pressure controller 12, and outputs it as the turbine steam control valve opening request signal 814, the turbine bypass valve opens. The degree request signal S15 is independent of the control valve opening signal S13, and the turbine bypass valve remains closed. On the other hand, if the low value selection circuit 14 selects the corrected load request signal S12 based on the load request signal S9 and the adjustment valve opening signal S13 and outputs it as the turbine steam adjustment valve opening request signal S14. ) are the turbine steam control valve opening request signal S14 and the control valve opening signal S
13 is approximately equal. Therefore, the turbine bypass valve opening request signal S15 based on the total steam flow rate request signal S4, the turbine steam regulator opening request signal 814, and the chattering prevention bias signal B2 is the regulator valve opening signal S
13.

FIG. 2 shows an example of the responses of the turbine steam control valve 2 and the turbine bypass valve 6 when load separation and connection operations are performed in a short period of time due to an accident in the power system 8. When the speed controller output signal S71 changes as shown in FIG. 2 as the load on the power system 8 increases or decreases, the turbine bypass is activated according to the moderator valve opening signal S13, which can be regarded as the operating characteristic of the turbine steam moderator valve 2. Since the operation of the valve 6 is controlled, the operating characteristics of the turbine steam control valve 2 and the turbine bypass valve 6 are approximately equal.

Since the operating characteristics of the turbine steam control valve 2 and the turbine bypass valve 6 are approximately equal, the flow of the steam generated in the reactor 1 is cooperatively controlled by the turbine steam control valve 2 and the turbine bypass valve 6. Therefore, almost no pressure fluctuation occurs in the reactor 1. Moreover, this makes it possible to suppress fluctuations in neutron flux and reactor water level.

The above is a case where the capacity of the turbine steam control valve 2 and the capacity of the turbine bypass valve 6 are equal. The capacity of the turbine bypass valve 6 is, for example, 25% of the capacity of the turbine control valve 2.
In such a case, in order to absorb the steam flow rate accompanying the opening and closing of the turbine steam control valve 2, a signal obtained by multiplying the turbine steam control valve opening degree request signal 814 by four and the total steam flow rate request signal S4 are used.
Based on, the turbine bypass valve opening request signal S15
You will get .

FIG. 3 shows another embodiment of the turbine control device for a nuclear power plant according to the present invention. The differences from FIG. 1 are the total steam flow rate request signal S4, which is the output of the pressure controller 12, the chattering prevention bias signal B2, and the control valve opening signal S1.
Based on 3. Modified bypass valve opening request signal 5153
The point is that the operation of the turbine bypass valve 6 is controlled by.

That is, the operation of the turbine bypass valve 6 in the opening direction and the closing direction is controlled by the moderation valve opening signal S13, which is the operating characteristic of the turbine steam moderation valve 2. As a result, the operations of the turbine steam control valve 2 and the turbine bypass valve 6 and the reactor pressure due to rapid load fluctuations exhibit responses as shown in FIG. 2. In addition, when the pressure of the reactor 1 rapidly rises above the operating speed of the turbine steam control valve 2, the total steam flow rate request signal S4 and the control valve opening signal S1
3 do not match, and the turbine steam control valve 2. as well as.

The reactor pressure can be stabilized by the response of the turbine bypass valve 6.

In the turbine control device for a nuclear power plant according to the present invention.

This is effective when the operating speed of the turbine bypass valve is faster than the operating speed of the turbine steam control valve.

If the operating speed of the turbine steam regulator can be made faster than the operating speed of the turbine bypass valve, the difference signal between the turbine bypass valve opening signal and the turbine bypass valve opening request signal and the turbine steam regulator Modified turbine adjustment valve opening request signal based on opening request signal
The opening degree of the turbine steam regulating valve is controlled.Thereby, the opening degree of the turbine steam regulating valve can be controlled by the turbine bypass valve opening signal, and the same effect as shown in FIG. 3 can be obtained.

〔Effect of the invention〕

According to the present invention, the operating characteristics of the turbine steam control valve and the turbine bypass valve can be made substantially equal. Thereby, fluctuations in the reactor pressure can be suppressed in the coordinated operation of the turbine steam control valve and the turbine bypass valve due to changes in the load on the power system. Furthermore, fluctuations in reactor water level and neutron flux can also be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of one embodiment of a turbine control device for a nuclear power plant according to the present invention, FIG. 2 is a response characteristic diagram of the present invention, and FIG. 3 is a system diagram of another embodiment of the present invention. , FIG. 4 is a system diagram of a conventional example of a turbine control device, and FIG. 5 is a response characteristic diagram of the conventional example. 1... Nuclear reactor, 2... Turbine steam control valve, 3...
・Turbine, 4... Condenser, 5... Water supply pump, 6
... Turbine bypass valve, 7... Generator, 8...
Power system, 12... Pressure controller, 13... Speed controller, 14... Low value selection circuit, 15... Control valve servo, 16... Bypass well servo, S4... Total steam Flow rate request signal, S9...Load request signal, S11...Adjustment valve opening deviation signal, 312...Corrected load request signal, 81
3...Adjustment valve.

Claims (1)

[Claims] 1. A pressure controller that controls reactor pressure based on a reactor pressure signal, a speed controller that controls turbine speed based on a turbine speed signal, and the pressure controller and the speed controller. and means for controlling the opening degrees of the turbine steam control valve and the turbine bypass valve based on the output signal of the opening degree detector of the turbine steam control valve and the turbine steam control valve, the output of the speed controller A nuclear power plant, comprising means for controlling the opening of the turbine bypass valve based on a load request signal, which is an addition signal of the signal and a load setting signal, and an output signal of the opening detector. Turbine control device. 2. A patent characterized in that means is provided for controlling the opening degree of the turbine bypass valve based on the total steam flow rate request signal which is the output signal of the pressure controller and the output signal of the opening degree detector. A turbine control device for a nuclear power plant according to claim 1.