JPS63243411A - Control device for generating plant - Google Patents

Abstract

PURPOSE:To enhance the safety and reliability of a generating plant by setting back a plant output instruction signal automatically when it is detected that a demand instruction signal for a steam flow rate is below the plant output instruction signal. CONSTITUTION:The titled device comprises an output instruction device 17, a nuclear reactor output control device 18, primary and secondary cooling system flow rate control devices 19 and 20, a feed water flow rate control device 21 and a main steam pressure control device 22. And the titled device is so controlled as to make a plant output signal from an output instruction device 17 approximately proportional to a main cooling system flow rate within the range of the rated plant output, for example, within 40% to 100% of the output, and the output of a nuclear reactor is concurrently adjusted, thereby making turbine generator output follow up the nuclear reactor output. In this case, it is detected whether a flow demand instruction signal to a governing valve 11 drops below a plant output instruction signal, and the titled device is so constituted that the plant output instruction signal is automatically set back, when there is any drop detected.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a power generation plant control device that determines plant output, and particularly to a setback of a plant output command when a turbine generator output decreases. This invention relates to an improved power plant control device.

(Prior Art) An example of a conventional power generation plant and its control device will be described with reference to a system diagram of an FBR power generation plant shown in FIG.

In the figure, the amount of heat generated in the reactor vessel 1 is circulated through the primary main cooling system by the primary main cooling system circulation pump 3 using liquid sodium as a coolant, and is circulated through the intermediate heat exchanger 2 of the primary main cooling system. heat is exchanged to the secondary main cooling system. Similarly to the primary main cooling system, the secondary main cooling system also uses liquid sodium as a coolant, which is circulated through the secondary main cooling system by a secondary main cooling system circulation pump 6, and steam is generated by a superheater 4 and an evaporator 5. Heat is exchanged with the steam system surrounding the device. In the steam system around the steam generator, heat from the secondary main cooling system is transferred to the superheater 4 and evaporator 5.
The superheated steam generated as a result of heat exchange is transferred to the steam control valve 1.
1 to the high pressure turbine 13, roughly to the low pressure turbine 1
4, the high-pressure turbine 13 and the low-pressure turbine 14 are rotated, and the generator 15 is driven to generate electricity. The steam that has done work in the high pressure turbine 13 and low pressure turbine 14 is transferred to the condenser 1
6, the water is condensed, a condensate pump 7, a feed water heater 8. The water is refluxed to the evaporator 5 via the water supply pump 9. A portion of the steam from upstream of the steam control valve 11 is directly condensed in the condenser 16 via the turbine bypass valve 12 .

In addition, a water supply control valve 1 is connected to the water supply line on the inlet side of the evaporator 5.
0 is provided, and the water supply flow rate is adjusted thereby.

Thus, the power generation plant control device having the above configuration has an output command device 17. Reactor power control device 18, primary main cooling system flow rate control device 19, secondary main cooling system flow control device 20. Water supply flow rate control device 21. It consists of a main steam pressure control 611 device 22. This power plant control device performs automatic control during normal plant operation, and within the range of, for example, 40% to 100% of the rated plant output,
It has a function of controlling the plant output command from the output command device 17 and the main cooling system flow rate so that they are almost proportional to each other, and at the same time adjusting the reactor output and making the turbine power output output follow the reactor output.

Next, each control W constituting the power plant control device
The J device will be explained.

The output command device 17 transmits a plant output command signal at a predetermined rate of change to each of the lower stage control devices 18 to 22 by a plant output increase/decrease command from a computer or by manual operation, and determines the plant output. Also, by the generation of the back signal, the plant output command signal falls at a preset rate of decline, and continues until it reaches, for example, 40% of the plant output command value.

However, when the set pack signal is released, the plant output command is configured to maintain the value at that time.

The reactor power control device 18 controls the driving speed of the control rods and adjusts the reactor power so that the outlet sodium temperature of the reactor vessel becomes a value corresponding to the plant output command signal from the power command device 17. Additionally, in order to improve the responsiveness and stability of the reactor output, feedback without thermal delay is provided using neutron signals corresponding to the reactor output.

The primary main cooling system flow control device 19 controls the flow ff1il measurement signal and the primary main cooling system circulation pump 3 so that the circulation flow rate of the primary main cooling system becomes a value corresponding to the plant output command from the output command device 17. The rotation speed signal of the primary main cooling system circulation pump 3 is fed back to adjust the rotation speed of the primary main cooling system circulation pump 3.

The secondary main cooling system flow mother control device 20 basically has the same configuration as the primary main cooling system flow m control device 19, and the circulation flow rate of the secondary main cooling system is controlled by the plant output command signal from the output command device 17. The flow rate measurement signal is fed back and the rotation speed of the secondary main cooling system circulation pump 6 is adjusted so as to have a value corresponding to .

When the feed water flow rate is automatically controlled during normal operation, the feed water flow control device 21 operates the opening degree of the feed water control valve 10 so that the evaporator outlet steam temperature becomes a constant value, and The water supply flow m is adjusted by operating the rotational speed of the water supply pump 9 so that the differential pressure at the inlet and outlet of the water supply valve 10, which can change as a result of a 1 degree change in Ef of 10, becomes a constant value. In addition, when the plant output command from the output command device 17 is changed, immediate response,
To improve stability, a plant output command signal is input and a flow rate measurement signal without thermal delay is fed back for compensation.

During normal operation, the main steam pressure control device 22 detects fluctuations in the main steam pressure that occur as a result of changing the output on the reactor side based on the plant output command, and controls the steam control valve 11 to keep the main steam pressure constant. It is operated and controlled to follow the plant output command to achieve a predetermined load. On the other hand, when the steam control valve 11 is throttled and the main steam pressure increases, in order to maintain the main steam pressure at a predetermined value, the rise in the main steam pressure is detected and the turbine bypass valve 12 is opened to reduce the main steam pressure. It is configured to allow

Next, the control circuit of the main steam pressure control device 22 will be explained in detail with reference to the logic circuit diagram of FIG.

First, the steam control valve flow rate request command signal is a signal obtained by outputting a pressure control signal and a speed/load control signal through the low value selection circuit 25. Here, the speed/load control signal is a speed deviation signal of the deviation between the load setting device setting value, the turbine speed setting value, and the actual speed, which is 1/CV. . A signal multiplied by the reciprocal of the Cv adjustment rate by the multiplier 24 is also added. In addition, the pressure control signal is the deviation between the main steam pressure setting value and the actual main steam pressure by 1/P,
. . It is multiplied by the reciprocal of the pressure adjustment rate by the multiplier 23.

Next, the turbine bypass valve flow rate request command signal is the deviation between the aforementioned pressure control signal and the steam control valve flow rate request command signal. The steam regulator valve 11 and the turbine bypass valve 12 are driven by a steam regulator flow rate command signal and a turbine bypass valve flow rate request command signal, respectively, via a valve position control circuit. Normally, the load setter set value is biased and the low value selection circuit 25 is configured to give priority to the pressure control signal and output it, but if the load on the power system side decreases, When the turbine rotation speed increases, priority is given to the speed/load control signal and the steam control valve flow rate request command signal decreases, so the steam control valve 11 is throttled down, and at the same time, the turbine bypass valve flow rate request command signal increases. Turbine bypass valve 12 opens. This controls the main steam pressure to be constant.

Here, the conventional setback of the output command signal issued from the aforementioned output command device 17 is as shown in the logic circuit of FIG. 4, when the reactor output is 40% or more, the generator output decreases and the The throttle valve 11 and the opening of the turbine bypass valve 12 are used as a setback signal, and the output command signal is lowered at a predetermined lowering rate.

(Problems to be Solved by the Invention) In the case of the above-mentioned power plant control device, when the load on the power system side decreases, the steam control valve 11 is automatically throttled down, the turbine bypass valve 12 is closed, and accordingly. There is no problem because the output command signal that is not present will be set back.

However, if an accident occurs where one of the two feed water pumps trips, the main steam pressure will drop as the steam flow rate decreases, the steam control valve 11 will be throttled, and as a result, the turbine/generator will Although the output also decreases, since the turbine bypass valve 12 does not open, the output command signal from the output command device 17 is not set back. Therefore, it is necessary for the operator to manually lower the output command signal, but if this is left unattended, the feedwater flow mother control device @21 will attempt to maintain the evaporator outlet steam temperature at a predetermined value. The water supply control valve 10 opens and tries to secure the water supply flow rate, but because one of the water supply pumps 9 has tripped, the predetermined water supply flow rate cannot be obtained, and the steam temperature at the evaporator outlet rises, creating a dangerous situation for the plant. There is a possibility of falling into.

The present invention was made in view of the above circumstances, and its purpose is to reduce the main steam flow rate due to a decrease in the load on the power system side, as well as due to a trip accident of one water pump, etc., and to reduce the output of the turbine generator. An object of the present invention is to provide a power generation plant control device that automatically sets back an output command signal even when the output command signal decreases.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention automatically controls the reactor output, coolant flow rate, main steam pressure, etc. using a plant output command signal. In a power generation plant control device that determines the output, detecting that a flow rate request command signal to a steam control valve that adjusts the flow rate of steam passing through the turbine in order to control the main steam pressure at a constant level has dropped from the plant output command signal, Said plan automatically! - It is characterized in that it is configured to output a setback signal that sets back the output command signal.

The setback signal is output when the AND condition of "the deviation between the plant output command signal and the steam regulating valve flow rate request command signal is a predetermined value % or more" and "the reactor output is 40% or more" is satisfied.

(Function) In the power plant control device of the present invention, during normal operation (reactor output 40% or more), even if the load on the power system side decreases and the turbine rotational speed increases, the steam control valve flow rate request command signal remains unchanged. Since the output command signal decreases, the condition that the deviation of (plant output command signal) - (steam control valve flow rate request command signal) is greater than or equal to a predetermined value % is established, and the output command signal is set back. In addition, even if the main steam pressure decreases due to a trip accident of one feedwater pump, and the turbine generator output decreases, the steam control valve flow rate request command signal decreases, so the above condition is satisfied, and the output command signal Set back.

(Example) Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a logic circuit diagram of an embodiment of the present invention.
The figure shows a setback circuit for output command signals. As shown in the figure, during normal operation (reactor output 40% or more), if the main steam pressure decreases due to an increase in the turbine speed due to a load reduction on the power system side or a minimum decrease in the main steam flow, the steam By reducing the control valve flow request command,
When the deviation from the plant output command increases and exceeds a certain value, the output command signal drops at a predetermined rate of decline,
Continue until the 40% plant output command is reached.

The main cooling system flow rate and reactor output are also controlled to values corresponding to the plant output command. Furthermore, if the plant output command is not lowered, but the setback conditions are no longer met, the lowering is stopped and the value at that point is maintained.

As described above, according to the power plant control device according to the present invention, instead of using the AND condition of "reactor output 40% or more" and "turbine bypass valve open" signal as in the conventional case,
The plant output command signal and the steam regulating valve flow rate request command signal are compared, and it is determined that "the deviation between the plant output command signal and the steam regulating valve flow rate demand command signal is a predetermined value % or more" and "the reactor output 4
A setback signal is output when the AND condition of "0% or more" is met, so if the load on the power system decreases, or if one water pump trips, etc., the main steam flow rate decreases. Even when the turbine generator output drops, the output command signal can be automatically set back without operator intervention.

[Effects of the Invention] As explained above, according to the power generation plant control device of the present invention, the main steam flow rate is reduced not only when the load on the power system side decreases but also due to a trip accident of one feed water pump, etc. Even if the output of the turbine generator decreases, the output command signal can be automatically set back without operator intervention, greatly improving the safety and reliability of the power plant. It has an excellent effect.

[Brief explanation of drawings]

Fig. 1 is a logic circuit diagram of an embodiment of the present invention, Fig. 2 is a system diagram of a power generation plant to which the present invention is applied and its control configuration diagram, and Fig. 3 is a logic circuit diagram of conventional main steam pressure control. , FIG. 4 is a conventional output command signal cellar 1-back logic circuit diagram. 17... Output command device 18... Reactor power control device 19... Primary main cooling system flow rate control device 20... Secondary main cooling system flow rate control 2Il device 21...
Feed water flow rate control device 22...Main steam pressure control device Agent Patent attorney Nori Chika Ken Yudo Hirofumi Mitsumata jI! I 3rd rgI Kaya 4rl! l

Claims (2)

[Claims] (1) In a power generation plant control device that determines plant output by automatically controlling reactor output, coolant flow rate, main steam pressure, etc. based on a plant output command signal, a turbine is used to control the main steam pressure at a constant level. It is configured to detect that a flow rate request command signal to a steam control valve that adjusts the flow rate of passing steam has fallen below the plant output command signal, and output a setback signal that automatically sets back the plant output command signal. A power generation plant control device characterized by: (2) The setback signal is an AND condition of "the deviation between the plant output command signal and the steam regulator flow rate request command signal is a predetermined value % or more" and "the reactor output is 40% or more" Claim 1 The power plant control device described.