JP2026003268A - Plant control device and plant control method - Google Patents

Abstract

A plant control device capable of appropriately controlling a power generation plant is provided.
[Solution] A plant control device 260 is provided with a turbine bypass valve control unit 212 that is provided in a power generation plant 201 and determines whether to open a turbine bypass valve 302 based on an external power transmission amount PA, which is the power supplied to an external power system 204, and an equipment power consumption PB, which is the power supplied to a power load equipment 230, and a power load equipment adjustment unit 234 that adjusts the equipment power consumption PB.
[Selected Figure] Figure 2

Description

The present invention relates to a plant control device and a plant control method.

The introduction of renewable energy is progressing worldwide in an effort to achieve a decarbonized society. However, it is expected that power grids to which renewable energy is connected will face various challenges, including supply-demand balance, excess transmission capacity, voltage fluctuations, frequency fluctuations, and stability. This is due to the uneven distribution of locations suitable for the introduction of variable renewable energy sources such as solar and wind power, which increases the flow of electricity from power generation areas to demand areas, making it more likely that localized overloads on transmission lines will occur. Furthermore, technology has been developed to temporarily disconnect generators from the power grid in the event of a power line break due to a lightning strike or typhoon, thereby eliminating localized overloads on transmission lines.

For example, the abstract of Patent Document 1 below states, "The system stabilization device includes a system data creation unit 103 that creates system data based on collected power system information; a basic shearing control unit selection unit 104 that selects target generators for power supply restriction to maintain power system stability based on predetermined rules; a frequency model creation unit 105 that creates a reference frequency model that simulates the frequency response in the power system under conditions where a predetermined time has passed since power supply restriction; a frequency stability determination unit 106 that determines frequency stability using the created model; a shearing control unit target change unit 107 that changes the target generators for power supply restriction selected by the basic shearing control unit selection unit based on the determination result; a memory unit 101 that stores the determined shearing control unit change information; and a control signal transmission unit 108 that transmits control signals to the target generators for power supply restriction indicated by the shearing control unit change information when a system accident occurs."

[Patent Document 1] JP 2023-23185 A

However, in the above-mentioned technology, there is a demand for more appropriate control of the power plant.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a plant control device and a plant control method that can appropriately control a power generation plant.

To solve the above problem, the plant control device of the present invention is installed in a power generation plant that includes a steam generation source, a turbine driven by steam generated from the steam generation source, a generator coupled to the turbine, connected to an external power system and power load equipment, and outputting generator output power, a condenser that liquefies the supplied steam, and a turbine bypass valve that supplies a larger amount of steam generated from the steam generation source to the condenser as its opening becomes larger. The plant control device is characterized by including: a turbine bypass valve control unit that determines whether to open the turbine bypass valve based on the external power transmission amount, which is the power supplied to the external power system, and the equipment power consumption, which is the power supplied to the power load equipment; and a power load equipment adjustment unit that adjusts the equipment power consumption.

The present invention enables appropriate control of power plants.

FIG. 1 is an illustration of a typical power supply limitation for a power plant. FIG. 2 is a block diagram of a power transmission system according to the first embodiment. 1 is a schematic block diagram of a steam system in a nuclear power plant. FIG. 1 is a schematic diagram of a main part of a steam system. FIG. 2 is a schematic diagram illustrating control content according to the first embodiment. FIG. 10 is another schematic diagram illustrating the control content of the first embodiment. 4 is a flowchart of a control routine in the first embodiment. 3A to 3C are waveform diagrams of various parts in the first embodiment. FIG. 11 is a diagram illustrating an example of reliability information according to the second embodiment. 10 is a flowchart of a control routine in a second embodiment. FIG. 11 is a block diagram of a power transmission system according to a third embodiment. FIG. 2 is a diagram showing an example of a display screen displayed on a display of a central load control device. 10A to 10C are waveform diagrams of various parts in the third embodiment. FIG. 1 is a block diagram of a computer.

[Overview of the embodiment]
Figure 1 is an explanatory diagram of a typical power supply restriction for a power plant. Note that power supply restriction (hereinafter sometimes referred to as "power restriction") generally refers to disconnecting a generator from the power grid.
In Figure 1, the vertical axis represents power and the horizontal axis represents time. In Figure 1, output power Pout is power transmitted from the generator of the power plant to the power grid. Before time t1, output power Pout is P1, but after time t1, output power Pout becomes P2. In the example shown, power P2 is generally "0". This means that a grid failure occurred at time t1 and the generator was disconnected from the power grid.

When power outages are imposed on a generator, it is no longer able to transmit the electricity it generates to the external power grid, and the excess electricity causes the generator to accelerate. At thermal power plants, the reactor output is shut down along with power outages to prevent the generator from accelerating. Nuclear power plants can also be operated in a similar manner to thermal power plants. That is, at nuclear power plants, the reactor can be shut down by inserting control rods into the reactor in an operation known as "scram" (emergency shutdown). However, when a scram is implemented, it takes several weeks to restore operation, which means that opportunities to sell electricity during the shutdown are missed.

Therefore, in the embodiment described below, the amount of power transmitted from the nuclear power plant to the external power grid is reduced while minimizing the risk of the nuclear power plant scramming during power outages. While the specific configuration will be described later, the embodiment described below coordinates control between the TBV (Turbine Bypass Valve), a balance of plant (BOP) device at the nuclear power plant, and the power load equipment connected to the nuclear power plant's private power lines. This power load equipment is, for example, a data center. By coordinating control between the nuclear reactor and the power load equipment, steam from the reactor is temporarily diverted to the condenser while gradually increasing the power load equipment, allowing all of the power from the nuclear power plant to be consumed by the power load equipment. This allows the nuclear power plant to avoid a scram in response to a power outage instruction. Avoiding a scram also ensures opportunities to sell electricity. The turbine bypass valve is a valve installed to allow excess steam from the reactor to bypass the turbine and escape to the condenser during startup, shutdown, load shedding, etc.

[First embodiment]
<Configuration of First Embodiment>
FIG. 2 is a block diagram of the power transmission system 101 in the first embodiment.
2, the power transmission system 101 includes a nuclear power plant 201 (power generation plant), a power transmission line 202, a transformer 203, an external power system 204, and power load equipment 230. The nuclear power plant 201 also includes an in-plant control device 210 (computer).

The power plant control device 210 is equipped with a TBV control unit 212 (turbine bypass valve control unit, turbine bypass valve control process), a CV controller 214, a scram control unit 216, and an EHC/TBV control unit 218. Here, CV stands for "Control Valve" and EHC stands for "Electro Hydraulic Controller."

The reliability determination unit 220, indicated by the dashed line, is applied to the second embodiment described below and is not included in the power plant control device 210 of the first embodiment. The power load equipment 230 also includes a calculation amount adjustment unit 234 (computer, power load equipment adjustment unit, power load equipment adjustment process) and multiple load computers 232. While a "load computer" is a device with the configuration of a normal computer, it will be referred to as a "load computer" in this specification to distinguish it from computers included in the power plant control device 210, etc. The power plant control device 210 and the calculation amount adjustment unit 234 are collectively referred to as the plant control device 260.

The nuclear power plant 201 transmits power to an external power grid 204 via a transmission line 202 and a transformer 203 connected to the nuclear power plant 201. A power load facility 230, such as a data center, that can adjust power consumption is installed midway between the nuclear power plant 201 and the transformer 203. The power output from the nuclear power plant 201, i.e., the total power generated by the nuclear power plant 201, is called the generator output power PC. The power output from the generator output power PC to the external power grid 204 is called the external power transmission amount PA. The power supplied to the power load facility 230 from the generator output power PC is called the facility power consumption PB. Therefore, the external power transmission amount PA, the facility power consumption PB, and the generator output power PC have the relationship "PC = PA + PB."

The power plant control device 210 outputs an equipment power consumption command DPB to the calculation amount adjustment unit 234 as needed. The equipment power consumption command DPB commands the power load equipment 230 to consume equipment power PB.

The TBV control unit 212 determines whether or not to use the turbine bypass valve 302 shown in Figure 3, i.e., whether or not to open it. The calculation amount adjustment unit 234 adjusts the amount of power consumed by the power load equipment 230. The TBV control unit 212 and the calculation amount adjustment unit 234 coordinate control to avoid scrams during electrical control.

FIG. 3 is a schematic block diagram of a steam system 300 in a nuclear power plant 201 .
In FIG. 3 , the steam system 300 includes a nuclear reactor 301 , a turbine bypass valve 302 , two turbines 303 , a generator 304 , a condenser 305 , a steam control valve 310 , and a steam extraction valve 312 .

Steam generated from the nuclear reactor 301 of a nuclear power plant is output through the steam control valve 310 and then branched, with a portion of the steam being supplied to the turbine 303. This causes the turbine 303 to rotate and drive the generator 304. Another portion of the steam flows into the condenser 305 via the turbine bypass valve 302.

Figure 4 is a schematic diagram of the main parts of the steam system 300. That is, Figure 4 is a schematic diagram of Figure 3, focusing on the reactor 301, turbine bypass valve 302, turbine 303, generator 304, and condenser 305. Steam output from the reactor 301 is supplied to the turbine 303 and condenser 305. The amount of steam supplied to both is adjusted by the opening degree DP of the turbine bypass valve 302 (see Figure 8). The TBV control unit 212 then outputs an opening degree command signal DPC that commands the opening degree DP.

When the opening command signal DPC is supplied to the steam system 300 and the turbine bypass valve 302 opens, some of the steam from the reactor 301 flows into the condenser 305. As the opening of the turbine bypass valve 302 gradually increases, the amount of steam flowing into the condenser 305 gradually increases. Because the steam flowing into the condenser 305 does not contribute to power generation, it is possible to control the output of the generator 304 by controlling the turbine bypass valve 302.

However, there is an upper limit to the opening of the turbine bypass valve 302, and it may not be possible to flow all of the steam from the reactor 301 to the condenser 305. In existing nuclear power plants in Japan, there is an upper limit to the opening of the turbine bypass valve 302, and only about 30% of the main steam from the reactor 301 can be flowed to the condenser 305.

Figures 5 and 6 are schematic diagrams showing the control content of the first embodiment. That is, Figures 5 and 6 are diagrams for explaining the activation logic and scram logic of the turbine bypass valve 302 in the nuclear power plant 201. First, Figure 5 schematically shows the control content up to the occurrence of load shedding 501 when a power supply restriction command is issued from the external power system 204 to the power plant internal control device 210. Here, load shedding 501 refers to closing a circuit breaker (not shown) for the main transformer (not shown) of the nuclear power plant 201.

Load shedding 501 can occur due to several triggering events, including a drop in substation voltage 502, a drop in generator frequency 503, and a loss of external power supply 504. Here, "drop in substation voltage 502" refers to an event in which the output voltage of a transformer (not shown) included in the nuclear power plant 201 drops below a predetermined value. Furthermore, "drop in generator frequency 503" refers to an event in which the output frequency of the generator 304 drops below the allowable range. Furthermore, loss of external power supply 504 refers to the loss of power supply required for cooling the reactor 301, etc. When load shedding 501 occurs, the power plant control device 210 outputs a load shedding signal DSD.

Figure 6 shows a schematic diagram of the control logic in the power plant control device 210 from the time the load shedding signal DSD is generated until scram is executed. In the reactor shutdown initiation process 601, the power plant control device 210 determines whether it is possible to reduce the generator output power PC by controlling the turbine bypass valve 302. That is, the power plant control device 210 determines whether it is possible to reduce the generator output power PC by controlling the turbine bypass valve 302 based on the adjustment amount of the generator output power PC and the output adjustment time.

The required adjustment amount required for the generator output power PC is equal to the external power transmission amount PA (hereinafter referred to as the external power transmission amount PA1 at the time of shutdown) that was output to the external power grid 204 immediately before the occurrence of power control. If the power that can be reduced by controlling the turbine bypass valve 302 is defined as the reducible power PV, the power plant internal control device 210 determines that it is possible to reduce the generator output power PC by controlling the turbine bypass valve 302 when the following formula (1) is established:

PA1-PV < 0...(Formula 1)

As mentioned above, there is an upper limit to the opening degree DP of the turbine bypass valve 302. Therefore, when the reactor 301 is operating at rated output and all of the generator output power PC is being transmitted to the external power grid 204 as the external power transmission amount PA, PA > PV at all times. Therefore, in this case, it is impossible to flow all of the steam from the reactor 301 into the condenser 305.

The output adjustment time is determined based on the integrity of BOP equipment, such as the turbine bypass valve 302. For example, if the condenser 305 continues to flow steam with the turbine bypass valve 302 open, there is a possibility that the vacuum in the condenser 305 will deteriorate within a few tens of minutes. After power outages have begun, it would be desirable to be able to reconnect the external power grid 204 and the nuclear power plant 201 once the need for power outages has disappeared. However, if power outages are implemented for a long period of time, it will take too long for the external power grid 204 and the nuclear power plant 201 to be reconnected. In such cases, from the perspective of the integrity of the BOP equipment, the nuclear power plant 201 will need to be scrammed.

In other words, if the generator output power PC cannot be reduced by controlling the turbine bypass valve 302, the power plant control device 210 executes a scram of the nuclear power plant 201. More specifically, the power plant control device 210 executes a steam control valve full closure control 602 that fully closes the steam control valve 310 (see FIG. 3), and a TBV open control 603 that opens the turbine bypass valve 302. Furthermore, the power plant control device 210 executes a scram valve open control 604 that opens the scram valve (not shown), and then executes a rapid all control rod insertion control 605 that inserts all control rods (not shown) into the reactor 301 (steam generation source).

Figure 7 is a flowchart of the control routine in the first embodiment. This routine is executed by the power plant control device 210 shown in Figure 2, and is a control routine for adjusting the turbine bypass valve 302 and the power load equipment 230 to avoid, as much as possible, the rapid insertion of all control rods 605 after receiving a load shedding 501 signal.

First, when this routine starts, in step S10, the TBV control unit 212 receives a load shedding signal DSD. This load shedding signal DSD is a signal indicating that load shedding 501 has been performed. The external power transmission amount PA1 at the time of shedding is, more precisely, the external power transmission amount PA at the time the load shedding signal DSD was received.

Next, in step S12, the TBV control unit 212 determines whether the external power transmission amount PA1 at the time of interruption is equal to or less than the reducible power PV. If the determination here is "No," processing proceeds to step S18, and the power plant control device 210 executes the reactor shutdown initiation processing 601 and other processing shown in Figure 6, and processing of this routine ends.

If the determination in step S12 is "Yes," processing proceeds to step S14. Here, the TBV control unit 212 determines whether the power load equipment 230 can respond to the power reduction, i.e., whether the power load equipment 230 can absorb an additional load equivalent to the external power transmission amount PA1 at the time of interruption. If the determination here is "No," processing in step S18 described above is executed, and processing of this routine ends. On the other hand, if the determination in step S14 is "Yes," processing in steps S16 and S20 is executed in parallel.

First, in step S16, the power plant control device 210 opens the turbine bypass valve 302. That is, it supplies the steam system 300 with an opening command signal DPC (see FIG. 4) that opens the turbine bypass valve 302. In addition, in step S20, the power plant control device 210 outputs an equipment power consumption command DPB to the calculation amount adjustment unit 234, which increases the processing load on the load computer 232 (increases the equipment power consumption PB). In this case, the power plant control device 210 outputs the equipment power consumption command DPB to set the initial value of the equipment power consumption PB to the value obtained by subtracting the reducible power PV from the external power transmission amount PA1 at the time of shutdown. When the processing of steps S16 and S20 is completed, the processing of this routine ends.

Assume that the processing in step S16 temporarily flows steam corresponding to the external power transmission amount PA1 at the time of shutdown from the turbine bypass valve 302 to the condenser 305. As mentioned above, due to issues with the soundness of the BOP equipment, there is a limit to the adjustment time for opening the turbine bypass valve 302. Therefore, in this embodiment, the calculation amount adjustment unit 234 increases the equipment power consumption PB in the power load equipment 230 while keeping the turbine bypass valve 302 open.

Then, as the equipment power consumption PB increases, the opening degree DP of the turbine bypass valve 302 is reduced, thereby executing control to increase the generator output power PC. Therefore, after the turbine bypass valve 302 is opened, it is preferable for the calculation amount adjustment unit 234 to determine whether there is room to increase the equipment power consumption PB. Here, when the rated output of the generator 304 is the rated generator output power PC _st and the maximum value of the equipment power consumption PB is the maximum equipment power consumption PB _max , it is preferable to determine whether the following relationship holds true.

PC _st - PB _max < 0 (Formula 2)

Figure 8 is a waveform diagram of each part in the first embodiment. That is, Figure 8 is a diagram that schematically shows the time changes of the generator output power PC, which is the generator output power when the control of Figure 7 is executed, the opening degree DP, which indicates the opening degree of the turbine bypass valve 302 (see Figure 3), and the equipment power consumption PB of the power load equipment 230. Note that the units of the vertical axis for the generator output power PC, opening degree DP, and equipment power consumption PB are percentages. Assume that load shedding due to electrical control occurs at time t12 in Figure 8. In this case, the TBV control unit 212 increases the opening degree DP of the turbine bypass valve 302.

This reduces the generator output power PC, making it possible to avoid a scram of the nuclear power plant 201. Next, from time t14 onwards, the power plant control device 210 increases the equipment power consumption PB, and the TBV control unit 212 decreases the opening degree DP accordingly. As the opening degree DP decreases, the generator output power PC gradually increases from time t14 onwards.

Here, the TBV control unit 212 changes the opening degree DP of the turbine bypass valve 302 so that the increase per unit time ΔPB (not shown) in the equipment power consumption PB is equal to the increase per unit time ΔPC (not shown) in the generator output power PC. Then, from time t16 onwards, the generator output power PC becomes 100%, and the equipment power consumption PB becomes equal to the generator output power PC. In other words, the power load equipment 230 is in a state where it absorbs all of the generator output power PC.

As such, according to this embodiment, the generator output power PC can be reduced by temporarily increasing the opening degree DP of the turbine bypass valve 302. Then, by increasing the facility power consumption PB after increasing the opening degree DP, it is possible to avoid a scram even if the nuclear power plant 201 is cut off from the external power grid 204.

Second Embodiment
Next, a power transmission system according to a second embodiment will be described. The configuration of the power transmission system according to the second embodiment is the same as that of the power transmission system 101 according to the first embodiment (see FIG. 2 ), except for the following points. In the description of each embodiment, parts corresponding to parts in the other embodiments described above are denoted by the same reference numerals, and their description may be omitted.

In the first embodiment, scram after load shedding 501 (see Figure 5) was avoided by combining control of the turbine bypass valve 302 opening DP with control of the facility power consumption PB. However, for data centers and other specific examples of power load facility 230, facility standards are set for each purpose of use. Depending on these facility standards, operation during load shedding 501 may not be fully guaranteed. Furthermore, the introduction of highly reliable equipment presents challenges, such as the need to invest in measures against natural disasters such as tsunamis and earthquakes, and the need to secure emergency power sources.

In this embodiment, the power plant control device 210 is therefore equipped with a reliability determination unit 220, shown by the dashed line in Figure 2. The reliability determination unit 220 determines the reliability of the power load equipment 230 and, based on the determined reliability, determines whether or not to output the above-mentioned equipment power consumption command DPB to the calculation amount adjustment unit 234. If the equipment power consumption command DPB is not output, a scram is generated in the nuclear power plant 201. The reliability determination unit 220 stores reliability information 902 (see Figure 9) of the power load equipment 230 for each contingency fault as a database. The reliability determination unit 220 determines whether the operation of the power load equipment 230 in the event of a contingency fault is highly reliable, and determines whether to execute opening control of the turbine bypass valve 302.

FIG. 9 is a diagram showing an example of reliability information 902 in the second embodiment.
The reliability information 902 is a database that stores the reliability of the power load equipment 230 for each contingency. The contingency includes natural disasters such as earthquakes, tsunamis, and typhoons, and system failures such as power line failures and external power supply failures. The reliability of the power load equipment 230, which may be a data center, is also considered to be confidentiality, availability, and integrity.

"Confidentiality" refers to the reliability of human access in the event of a failure and the ability to secure routes for transporting goods. In the event of a natural disaster, it may be impossible to access the installation location of the power load equipment 230. Therefore, in the example shown, the reliability is set to low in the event of such a natural disaster, assuming that human access is not possible. On the other hand, in the event of a "system failure" or "external power supply loss," it is considered that there will be no problems with human access, and the reliability is set to high.

"Availability" refers to reliability, such as earthquake-resistant structures and the provision of private power generation. Regarding "disaster prevention structures," new regulatory design requirements have been established following the earthquake disaster for nuclear power plants regarding earthquake, tsunami, and typhoon countermeasures. Therefore, the disaster prevention measures required for the installation of power load equipment 230, such as data centers, have been implemented, and therefore reliability is deemed high. Regarding "external power supply failure," reliability is deemed high because it does not involve any changes to the physical structure of the power load equipment 230. When various anticipated failures occur, the use of "private power generation" is not considered an evaluation indicator. This is because, assuming "high reliability in the operation of power load equipment 230," private power generation is unnecessary in the event of a disaster.

Furthermore, "completeness" is an indicator of external complementation and backup of the results calculated by the power load equipment 230, which is, for example, a data center. In this embodiment, the power load equipment 230 is operated by the power plant control device 210, and the power load equipment 230 is increased by, for example, idling calculations in the event of a disaster. For this reason, the importance of backing up the calculation results is not great, and therefore "completeness" is not an indicator of reliability.

The contents of Figure 9 assume a data center as the type of power load equipment 230, but the reliability index can vary depending on the type of power load equipment 230. From this database, control of the turbine bypass valve 302 opening DP and equipment power consumption PB is performed only when the reliability of the power load equipment 230 operating correctly is high, thereby enabling operation that takes the reliability of the power load equipment 230 into consideration.

Fig. 10 is a flowchart of a control routine in the second embodiment. Like the routine in Fig. 7, this routine also aims to avoid the rapid insertion of all control rods control 605 (see Fig. 5) as much as possible after receiving a load shedding signal 501.
In Fig. 10, the processes of steps S30 to S34 and S36 to S40 are the same as the processes of steps S10 to S14 and S16 to S20 shown in Fig. 7. However, if the determination in step S34 in Fig. 10 is "Yes" (power load equipment 230 can respond to the power reduction), the process proceeds to step S35.

In step S35, the reliability determination unit 220 (see Figure 1) determines whether the power load equipment 230 satisfies a predetermined reliability condition. Here, the "reliability condition" is a condition that, as a result of comparing the currently occurring fault with the contents of the reliability information 902 (see Figure 9), the power load equipment 230 has a reliability level equal to or higher than a predetermined level. If the determination is "Yes," then in step S36 the power plant control device 210 opens the turbine bypass valve 302.

In parallel with this, the power plant control device 210 increases the processing load of the load computer 232 in step S40. If step S35 returns "No," processing proceeds to step S88. Here, the power plant control device 210 executes the reactor shutdown initiation processing 601 and other processing shown in Figure 6, and processing of this routine ends.

[Third embodiment]
FIG. 11 is a block diagram of the power transmission system 103 in the third embodiment.
The configuration of the power transmission system 103 is similar to that of the power transmission system 101 (see FIG. 2) according to the first embodiment, except for the following points.
First, the power transmission system 103 includes a central load control center 250 (control center) that is a control facility for the external power system 204. The central load control center 250 includes a central load control device 252. The calculation amount adjustment unit 234 of the power load facility 230 receives a signal from the central load control device 252 and changes the facility power consumption PB of the power load facility 230.

In the first embodiment described above, opening the turbine bypass valve 302 temporarily reduces the generator output power, i.e., the generator output power PC. However, there are cases where the amount of steam corresponding to the previous external power transmission amount PA is greater than the "amount of steam that can be flowed to the condenser when the turbine bypass valve 302 is fully open." In this case, opening the turbine bypass valve 302 is not enough to reduce the generator output power PC, and a scram occurs.

For this reason, it is considered advisable to adjust the external power transmission amount PA and the equipment power consumption amount PB to appropriate values in advance in preparation for an actual grid failure. However, reducing the external power transmission amount PA leads to a loss of power selling opportunities at the nuclear power plant 201. Therefore, in this embodiment, when the central load dispatching center 250 detects a sign of a grid failure, the external power transmission amount PA is reduced in advance in preparation for an actual grid failure.

FIG. 12 is a diagram showing an example of a display screen 1200 displayed on the display of the central power supply command device 252.
The display screen 1200 includes a system diagram display section 1201 and a system stability display section 1202. The central load control device 252 has a function of determining the content to be displayed on these displays by calculation. The system diagram display section 1201 displays the configuration of the external power system 204. The system diagram display section 1201 shows information about the external power system 204 to which the nuclear power plant 201 is connected, such as the locations of synchronous generators, renewable energy power sources, and loads, as well as the transformers, busbars, and lines that connect them.

The system stability display unit 1202 also displays the evaluation results of system stability when a system fault occurs in the power system shown in the system diagram display unit 1201. Examples of indicators include generator phase difference, voltage, and frequency. The system stability display unit 1202 in Figure 12 shows an evaluation result in which voltage drops when anticipated fault case C3 occurs. Anticipating this system fault, the central load dispatching device 252 adjusts the external power transmission amount PA and facility power consumption PB to avoid a scram when a fault occurs.

As a result, when the power plant control device 210 and the calculation amount adjustment unit 234 change the calculation amount of the load computer 232 in response to commands from the central power supply control device 252, they use either the generator phase angle difference between the multiple generators included in the external power system 204, the voltage in the external power system 204, or the frequency in the external power system 204 as a judgment indicator for changing the generator output power PC.

Figure 13 is a waveform diagram of each part in the third embodiment. That is, Figure 13 is a diagram that schematically shows the time changes of the generator output power PC, which is the generator output power when the control of the third embodiment is implemented, the opening degree DP, which indicates the opening degree of the turbine bypass valve 302, and the equipment power consumption PB of the power load equipment 230. Here, for the opening degree DP and the equipment power consumption PB, the waveforms shown by solid lines are waveforms when the central load control device 252 does not detect any signs of abnormality, and the waveforms shown by dashed lines are waveforms when any signs of abnormality are detected.

Let's assume that load shedding occurs at time t22. If an abnormality warning sign was detected before time t22, the central load dispatching device 252 increases the equipment power consumption PB, as shown by the dashed line, in preparation for load shedding. Therefore, when load shedding occurs at time t22, the opening degree DP, shown by the dashed line, is smaller than that shown by the solid line (when no abnormality warning sign is detected). By performing the above operations, by increasing the equipment power consumption PB only when there is a high possibility of load shedding or scram due to a system failure, it is possible to reduce the opening degree DP of the turbine bypass valve 302 when load shedding occurs.

[Computer Configuration]
Fig. 14 is a block diagram of the computer 980. The power plant control device 210, the calculation amount adjustment unit 234, and the central power supply command device 252 shown in Fig. 2 and Fig. 11 each include one or more computers 980 shown in Fig. 14.
14 , a computer 980 includes a CPU 981, a storage unit 982, a communication I/F (interface) 983, an input/output I/F 984, and a media I/F 985. Here, the storage unit 982 includes a RAM 982a, a ROM 982b, and an SSD (Solid State Drive) 982c. The communication I/F 983 is connected to a communication circuit 986. The input/output I/F 984 is connected to an input/output device 987. The media I/F 985 reads and writes data from a recording medium 988. The ROM 982b stores an IPL (Initial Program Loader) executed by the CPU, etc. The SSD 982c stores control programs, various data, etc. The CPU 981 realizes various functions by executing control programs, etc. loaded from the SSD 982c to the RAM 982a. The inside of the power plant control device 210 shown in FIGS. 2 and 11 is primarily shown as blocks of functions realized by control programs and the like.

[Modification]
The present invention is not limited to the above-described embodiments and various modifications are possible. The above-described embodiments are provided as examples to facilitate understanding of the present invention and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to delete part of the configuration of each embodiment, or to add or replace other configurations. Furthermore, the control lines and information lines shown in the figures are those considered necessary for explanation, and do not necessarily represent all control lines and information lines necessary for the product. In reality, it is possible to consider that almost all components are interconnected. Possible modifications of the above-described embodiments include, for example, the following:

(1) In the above embodiments, an example was described in which a nuclear power plant 201 was used as the power plant, but the power plant may also be a thermal power plant, etc.

(2) In each of the above embodiments, the power plant control device 210 and the calculation amount adjustment unit 234 may be implemented by the same computer.

(3) Since the hardware in the above embodiment, such as the power plant control device 210, calculation amount adjustment unit 234, and central power supply command device 252, can be implemented by a general-purpose computer, the processes corresponding to the above-mentioned block diagrams and flowcharts, as well as programs that execute the various processes described above, may be stored on a storage medium (a computer-readable storage medium on which a program is recorded) or distributed via a transmission path.

(4) In the above embodiment, the processes corresponding to the block diagrams and flowcharts, as well as the various other processes described above, are described as software processes using programs. However, some or all of these processes may be replaced with hardware processes using an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array), etc.

(5) The various processes performed in the above embodiments may be executed by a server computer via a network (not shown), and the various data stored in the above embodiments may also be stored on the server computer.

[Effects of the embodiment]
As described above, according to each of the above-described embodiments, the plant control device 260 includes a turbine bypass valve control unit (212) that determines whether or not to open the turbine bypass valve 302 based on the external power transmission amount PA, which is the power supplied to the external power system 204, and the equipment power consumption PB, which is the power supplied to the power load equipment 230, and a power load equipment adjustment unit (234) that adjusts the equipment power consumption PB. As a result, it is possible to determine whether or not to open the turbine bypass valve 302 based on the external power transmission amount PA and the equipment power consumption PB, so that scram can be avoided as much as possible and the power plant (201) can be appropriately controlled.

Furthermore, the power load equipment 230 is equipped with multiple load computers 232, and it is even more preferable for the power load equipment adjustment unit (234) to adjust the equipment power consumption PB by adjusting the calculation volume of the load computers 232. This allows the equipment power consumption PB to be adjusted according to the calculation volume of the load computers 232.

Furthermore, when a load shedding 501 occurs in which the power plant (201) is unable to transmit power to the external power grid 204, it is more preferable for the turbine bypass valve control unit (212) to open the turbine bypass valve 302 if the external power transmission amount PA at the time of load shedding 501, that is, the external power transmission amount PA at the time of shedding (external power transmission amount PA1 at the time of shedding), is smaller than the reducible power PV, which is the amount by which the generator output power PC can be reduced by opening the turbine bypass valve 302. This allows the turbine bypass valve 302 to be opened when the reducible power PV is greater than the external power transmission amount PA at the time of shedding.

Furthermore, when performing opening control of the turbine bypass valve 302, the turbine bypass valve control unit (212) transmits an equipment power consumption command DPB that commands the equipment power consumption PB to the power load equipment adjustment unit (234), and it is more preferable that the power load equipment adjustment unit (234) increases the amount of calculation in the load computer 232 based on the equipment power consumption command DPB, thereby increasing the equipment power consumption PB. This makes it possible to link the opening control of the turbine bypass valve 302 and the equipment power consumption PB based on the equipment power consumption command DPB.

Furthermore, it is more preferable that the turbine bypass valve control unit (212) reduces the opening degree DP of the turbine bypass valve 302 as the power load equipment adjustment unit (234) increases the calculation amount and equipment power consumption PB based on the equipment power consumption command DPB, thereby increasing the generator output power PC as the equipment power consumption PB increases. This allows the generator output power PC to increase accordingly as the equipment power consumption PB increases.

More preferably, the turbine bypass valve control unit (212) adjusts the opening degree DP of the turbine bypass valve 302 so that the increase per unit time ΔPB of the equipment power consumption PB based on the equipment power consumption command DPB is equal to the increase per unit time ΔPC of the generator output power PC. This makes it possible to equalize the increase per unit time ΔPB of the equipment power consumption PB and the increase per unit time ΔPC of the generator output power PC.

Furthermore, as in the second embodiment, the system further includes a reliability determination unit 220 that determines whether the reliability of the power load equipment 230 in the event of an actual failure satisfies a predetermined reliability condition by referencing reliability information 902 that defines the reliability according to a contingent failure of the power load equipment 230, and it is even more preferable that the turbine bypass valve control unit (212) transmits an equipment power consumption command DPB to the power load equipment adjustment unit (234) when the determination result of the reliability determination unit 220 is positive. This allows the turbine bypass valve control unit (212) to transmit an equipment power consumption command DPB to the power load equipment adjustment unit (234) when the power load equipment 230 satisfies the predetermined reliability condition.

Furthermore, as in the second embodiment, it is more preferable that the reliability information 902 includes any one of confidentiality, availability, or integrity related to the power load equipment 230. This allows the turbine bypass valve control unit (212) to transmit the equipment power consumption command DPB based on the confidentiality, availability, or integrity related to the power load equipment 230.

Furthermore, as in the third embodiment, it is even more preferable if the power load equipment adjustment unit (234) changes the amount of calculation of the load computer 232 in response to a command from the control center (250) that manages the external power system 204. This allows the control center (250) to control the amount of calculation of the load computer 232.

Furthermore, when the reducible power PV is smaller than the external power transmission amount PA1 during interruption, it is more preferable for the power load equipment adjustment unit (234) to set the equipment power consumption PB to a value obtained by subtracting the reducible power PV from the external power transmission amount PA1 during interruption. This allows the equipment power consumption PB to be set to an appropriate value.

Furthermore, when the power load equipment adjustment unit (234) changes the calculation volume of the load computer 232 in response to a command from the control center (250), it is more preferable to use any one of the generator phase angle difference between the multiple generators included in the external power system 204, the voltage in the external power system 204, or the frequency in the external power system 204 as a judgment indicator for changing the generator output power PC. This makes it possible to change the generator output power PC in accordance with the state of the external power system 204.

201 Nuclear power plant (power plant)
204 External power system 210 Power plant control device (computer)
212 TBV control unit (turbine bypass valve control unit, turbine bypass valve control process)
220 Reliability determination unit 230 Power load equipment 232 Load computer 234 Calculation amount adjustment unit (computer, power load equipment adjustment unit, power load equipment adjustment process)
250 Central Power Supply Control Center (Control Center)
260 Plant control device 301 Nuclear reactor (steam generation source)
302 Turbine bypass valve 303 Turbine 304 Generator 305 Condenser 501 Load shedding 902 Reliability information DP Opening degree PA External power transmission amount PB Equipment power consumption PC Generator output power PV Reducible power DPB Equipment power consumption command PA1 External power transmission amount at shedding ΔPB Increase amount ΔPC Increase amount

Claims (12)

a turbine bypass valve control unit provided in a power generation plant including a steam generation source, a turbine driven by steam generated from the steam generation source, a generator coupled to the turbine, connected to an external power system and power load equipment, and outputting generator output power, a condenser for liquefying the supplied steam, and a turbine bypass valve that supplies a larger amount of steam generated from the steam generation source to the condenser as the opening degree of the turbine bypass valve increases, the turbine bypass valve control unit determining whether to open the turbine bypass valve based on an external power transmission amount that is power supplied to the external power system and equipment power consumption that is power supplied to the power load equipment;
a power load equipment adjustment unit that adjusts the equipment power consumption. The power load facility includes a plurality of load computers,
The plant control device according to claim 1 , wherein the power load equipment adjustment unit adjusts the equipment power consumption by adjusting the amount of calculation of the load computer. 2. The plant control device according to claim 1, wherein, in the event of a load dump in which the power generation plant is unable to transmit electric power to the external electric power grid, the turbine bypass valve control unit opens the turbine bypass valve when an external power transmission amount during shutdown, which is the external power transmission amount at the time of the load dump, is smaller than a reduceable power, which is an amount by which the generator output power can be reduced by opening the turbine bypass valve. 3. The plant control device according to claim 2, wherein the turbine bypass valve control unit, when performing opening control of the turbine bypass valve, transmits an equipment power consumption command that commands the equipment power consumption to the power load equipment adjustment unit, and the power load equipment adjustment unit increases the equipment power consumption by increasing the amount of calculation of the load computer based on the equipment power consumption command. 5. The plant control device according to claim 4, wherein the turbine bypass valve control unit reduces the opening of the turbine bypass valve as the power load equipment adjustment unit increases the calculation amount and the equipment power consumption based on the equipment power consumption command, thereby increasing the generator output power as the equipment power consumption increases. The turbine bypass valve control unit
6. The plant control device according to claim 5, wherein the opening of the turbine bypass valve is adjusted so that an increase per unit time of the equipment power consumption based on the equipment power consumption command is equal to an increase per unit time of the generator output power. a reliability determination unit that determines whether the reliability of the power load equipment when a failure actually occurs satisfies a predetermined reliability condition by referring to reliability information that defines reliability according to a contingency failure of the power load equipment;
The plant control device according to claim 4 , wherein the turbine bypass valve control unit transmits the equipment power consumption command to the power load equipment adjusting unit when the determination result of the reliability determining unit is affirmative. The plant control device according to claim 7 , wherein the reliability information includes any one of confidentiality, availability, and integrity related to the power load equipment. The plant control device according to claim 2 , wherein the power load equipment adjusting unit changes the amount of calculation of the load computer in response to a command from a control center that manages the external power system. 4. The plant control device according to claim 3, wherein, when the reducible power is smaller than the amount of external power transmission during interruption, the power load equipment adjustment unit sets the equipment power consumption to a value obtained by subtracting the reducible power from the amount of external power transmission during interruption. 10. The plant control device according to claim 9, wherein when changing the calculation amount of the load computer in response to a command from the control center, the power load equipment adjustment unit uses any one of a generator phase angle difference between a plurality of generators included in the external power system, a voltage in the external power system, or a frequency in the external power system as a determination index for changing the generator output power. A plant control method for controlling a power plant including a steam generation source, a turbine driven by steam generated from the steam generation source, a generator coupled to the turbine, connected to an external power system and power load equipment, and outputting generator output power, a condenser for liquefying the supplied steam, a turbine bypass valve that supplies a larger amount of steam generated from the steam generation source to the condenser as the opening degree of the turbine bypass valve increases, and a computer,
The computer,
a turbine bypass valve control process that determines whether to open the turbine bypass valve based on an external power transmission amount that is power supplied to the external power grid and equipment power consumption that is power supplied to the power load equipment;
and a power load equipment adjustment step of adjusting the equipment power consumption.