Plant control device and plant control method

Abstract

Provided is a plant control device capable of appropriately controlling a power generation plant. A plant control device (260) is provided with: a turbine bypass valve control unit (212) that is provided to a power generation plant (201) and assesses whether or not to turn a turbine bypass valve (302) to open, on the basis of an external power transmission amount (PA) which is the power supplied to an external power system (204) and a facility power consumption (PB) which is the power supplied to a power load facility (230); and a power load facility adjustment unit (234) that adjusts the facility power consumption (PB).

Description

Plant control device and plant control method

[0001] The present invention relates to a plant control device and a plant control method.

[0002] The introduction of renewable energy sources is progressing worldwide in an effort to realize a decarbonized society. Power grids to which renewable energy sources are connected are expected to face various challenges, including supply-demand balance, excess transmission capacity, voltage fluctuations, frequency fluctuations, and stability. This is due to the uneven distribution of suitable locations for the introduction of variable renewable energy sources such as solar and wind power, which increases the flow of electricity from power generation sites to demand sites, making localized overloads on transmission lines more likely. Furthermore, technologies have 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.

[0003] For example, the abstract of Patent Document 1 below states that "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, based on predetermined rules, target generators for power supply restriction to maintain the stability of the power system; a frequency model creation unit 105 that creates a reference frequency model that simulates the response of frequency 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 a control signal to the target generators for power supply restriction indicated by the shearing control unit change information when a system accident occurs."

[0004] [Patent Document 1] JP 2023-23185 A

[0005] However, in the above-mentioned technology, there is a demand for more appropriate control of a power plant. The present invention has been made in view of the above-mentioned 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 plant.

[0006] In order to solve the above-mentioned problems, the plant control device of the present invention is 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 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 the opening degree of the turbine bypass valve increases, and is characterized by comprising: a turbine bypass valve control unit that determines 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, and a power load equipment adjustment unit that adjusts the equipment power consumption.

[0007] According to the present invention, the power plant can be appropriately controlled.

[0008] 1 is an explanatory diagram of general power supply restrictions for a power plant. FIG. 1 is a block diagram of a power transmission system in a first embodiment. FIG. 2 is a schematic block diagram of a steam system in a nuclear power plant. FIG. 3 is a schematic diagram of a main part of a steam system. FIG. 4 is a schematic diagram showing the control content of the first embodiment. FIG. 5 is another schematic diagram showing the control content of the first embodiment. FIG. 6 is a flowchart of a control routine in the first embodiment. FIG. 7 is a waveform diagram of each part in the first embodiment. FIG. 8 is a diagram showing an example of reliability information in a second embodiment. FIG. 9 is a flowchart of a control routine in the second embodiment. FIG. 10 is a block diagram of a power transmission system in a third embodiment. FIG. 11 is a diagram showing an example of a display screen displayed on the display of a central load control device. FIG. 12 is a waveform diagram of each part in the third embodiment. FIG. 13 is a block diagram of a computer.

[0009] [Outline of the embodiment] Fig. 1 is an explanatory diagram of a general power supply restriction for a power plant. Note that power supply restriction (hereinafter sometimes referred to as "power control") generally refers to disconnecting a generator from the power grid. In Fig. 1, the vertical axis represents power, and the horizontal axis represents time. In Fig. 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 illustrated example, power P2 is generally "0". This means that a grid failure occurred at time t1, and the generator was disconnected from the power grid.

[0010] 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 the same way as 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 creates the problem of missing opportunities to sell electricity during the shutdown period.

[0011] Therefore, in the embodiment described below, the amount of power transmitted from the nuclear power plant to the external power grid is reduced while avoiding a scram of the nuclear power plant as much as possible during power outages. While a specific configuration will be described later, in the embodiment described below, cooperative control is performed between a turbine bypass valve (TBV), which is a balance of plant (BOP) device of the nuclear power plant, and power load equipment connected to the nuclear power plant's private power lines. This power load equipment is, for example, a data center. By cooperative control between the nuclear reactor and the power load equipment, steam from the nuclear reactor is temporarily diverted to the condenser while gradually increasing the power load equipment, enabling all of the power from the nuclear power plant to be consumed by the power load equipment. As a result, according to the embodiment described below, the nuclear power plant can 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 provided to allow excess steam from the reactor to bypass the turbine and escape to the condenser during startup, shutdown, load shedding, etc.

[0012] [First embodiment] <Configuration of first embodiment> Fig. 2 is a block diagram of a power transmission system 101 in the first embodiment. In Fig. 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).

[0013] The in-plant control device 210 includes 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."

[0014] The reliability determination unit 220 indicated by the dashed line is applied to a second embodiment described later, and is not included in the in-power plant control device 210 of the first embodiment. The power load equipment 230 is equipped with a calculation amount adjustment unit 234 (computer, power load equipment adjustment unit, power load equipment adjustment process) and a plurality of load computers 232. Although a "load computer" is a device having the configuration of a normal computer, it is referred to as a "load computer" in this specification to distinguish it from computers included in the in-power plant control device 210, etc. The in-power plant control device 210 and the calculation amount adjustment unit 234 are collectively referred to as a plant control device 260.

[0015] A 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 referred to as the generator output power PC. Of the generator output power PC, the power output to the external power grid 204 is referred to as the external power transmission amount PA. Of the generator output power PC, the power supplied to the power load facility 230 is referred to as 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."

[0016] The power plant control device 210 outputs an equipment power consumption command DPB as needed to the calculation amount adjustment unit 234. The equipment power consumption command DPB commands the power load equipment 230 to consume equipment power PB.

[0017] The TBV control unit 212 determines whether or not to use the turbine bypass valve 302 shown in Fig. 3, i.e., whether or not to open the valve. 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 perform cooperative control to avoid a scram during electrical control.

[0018] 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.

[0019] Steam generated from a nuclear reactor 301 of a nuclear power plant is output via a steam control valve 310 and then branched, with a portion of the steam being supplied to a turbine 303. This causes a generator 304 to rotate and drive by the turbine 303. Another portion of the steam flows into a condenser 305 via a turbine bypass valve 302.

[0020] Fig. 4 is a schematic diagram of the main parts of the steam system 300. That is, Fig. 4 is a schematic diagram of Fig. 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 (see Fig. 8) of the turbine bypass valve 302. The TBV control unit 212 outputs an opening degree command signal DPC that commands the opening degree DP.

[0021] When the opening command signal DPC is supplied to the steam system 300 and the turbine bypass valve 302 is opened, a portion of the steam from the reactor 301 flows into the condenser 305. Then, 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.

[0022] However, there is an upper limit to the opening degree of the turbine bypass valve 302, and there is a possibility that not all of the steam from the reactor 301 can be made to flow to the condenser 305. In existing nuclear power plants in Japan, there is an upper limit to the opening degree of the turbine bypass valve 302, and the steam that can be made to flow to the condenser 305 is approximately 30% of the main steam from the reactor 301.

[0023] 5 and 6 are schematic diagrams illustrating the control content of the first embodiment. That is, FIGS. 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, FIG. 5 schematically illustrates the control content up to the occurrence of load shedding 501 when a power supply limitation 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.

[0024] Load dumping 501 can occur due to several triggering events, such as a substation voltage drop 502, a generator frequency drop 503, and an external power supply loss 504. Here, the "substation voltage drop 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. The "generator frequency drop 503" refers to an event in which the output frequency of the generator 304 drops below an allowable range. The external power supply loss 504 refers to a loss of power supply necessary for cooling the nuclear reactor 301, etc. When the load dumping 501 occurs, the power plant control device 210 outputs a load dump signal DSD.

[0025] 6 schematically shows the control logic in the power plant control device 210 from the generation of the load shedding signal DSD 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.

[0026] 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 cutoff external power transmission amount PA1) 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)

[0027] As described 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.

[0028] 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 degree of vacuum in the condenser 305 will deteriorate in about several tens of minutes. After power outage control is initiated, it is desirable to be able to reconnect the external power grid 204 and the nuclear power plant 201 once the need for power outage control is eliminated. However, if the time during which power outage control is being implemented is prolonged, it will take too long to reconnect the external power grid 204 and the nuclear power plant 201. In such a case, from the perspective of the integrity of the BOP equipment, the nuclear power plant 201 will be scrammed.

[0029] That is, if the generator output power PC cannot be reduced by controlling the turbine bypass valve 302, the in-plant control device 210 executes scram of the nuclear power plant 201. More specifically, the in-plant control device 210 executes steam control valve full closure control 602, which fully closes the steam control valve 310 (see FIG. 3 ), and TBV open control 603, which opens the turbine bypass valve 302. Furthermore, the in-plant control device 210 executes scram valve open control 604, which opens a scram valve (not shown), and then executes all control rod rapid insertion control 605, which inserts all control rods (not shown) into the reactor 301 (steam generation source).

[0030] 7 is a flowchart of a control routine in the first embodiment. This routine is executed by the power plant control device 210 shown in FIG. 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 execution of the rapid insertion control of all control rods 605 after receiving a load shedding signal 501.

[0031] 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 executed. More precisely, the external power transmission amount PA1 at the time of shedding is the external power transmission amount PA at the time the load shedding signal DSD is received.

[0032] Next, in step S12, the TBV control unit 212 determines whether the external power transmission amount PA1 at the time of shutdown is equal to or less than the reducible power PV. If the determination here is "No," the process proceeds to step S18, and the power plant control device 210 executes the reactor shutdown initiation process 601 and other processes shown in FIG. 6, and the process of this routine ends.

[0033] If the determination in step S12 is "Yes," the process proceeds to step S14. Here, the TBV control unit 212 determines whether the power load equipment 230 can respond to the power reduction, that is, whether the power load equipment 230 can additionally absorb a load equivalent to the external power transmission amount PA1 at the time of interruption. If the determination here is "No," the process of step S18 described above is executed, and the process of this routine ends. On the other hand, if the determination in step S14 is "Yes," the processes of steps S16 and S20 are executed in parallel.

[0034] 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. Then, 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 of 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 so as to set the initial value of the equipment power consumption PB to a 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.

[0035] It is assumed that steam corresponding to the amount of external power transmission PA1 during shutdown is temporarily flowed from the turbine bypass valve 302 to the condenser 305 by the processing of step S16. As described above, due to issues regarding 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.

[0036] Then, as the facility 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 to determine by the calculation amount adjustment unit 234 whether there is room to increase the facility power consumption PB. Here, the rated output of the generator 304 is set to the rated generator output power PC st , the maximum value of the equipment power consumption PB is max When this is the case, it is advisable to determine whether the following relationship holds: st -PB max < 0...(Formula 2)

[0037] Figure 8 is a waveform diagram of each part in the first embodiment. That is, Figure 8 is a diagram that schematically shows changes over time in the generator output power PC, which is the generator output power, the opening DP, which indicates the opening of the turbine bypass valve 302 (see Figure 3), and the equipment power consumption PB of the power load equipment 230 when the control of Figure 7 is executed. Note that the units on the vertical axis for the generator output power PC, the opening DP, and the 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 DP of the turbine bypass valve 302.

[0038] This reduces the generator output power PC, making it possible to avoid a scram of the nuclear power plant 201. Next, after time t14, the power plant control device 210 increases the facility 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 after time t14.

[0039] Here, the TBV control unit 212 changes the opening degree DP of the turbine bypass valve 302 so that the increase amount ΔPB (not shown) per unit time of the equipment power consumption PB is equal to the increase amount ΔPC (not shown) per unit time of the generator output power PC. Then, after time t16, 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.

[0040] As described above, 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.

[0041] [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 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 of the other embodiments described above are denoted by the same reference numerals, and their description may be omitted.

[0042] In the first embodiment, a scram after load shedding 501 (see FIG. 5 ) occurs is avoided by combining control of the opening degree DP of the turbine bypass valve 302 and control of the facility power consumption PB. On the other hand, for a data center or the like, which is a specific example of the 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 poses challenges, such as the need for investment in the introduction of such equipment, such as measures against natural disasters such as tsunamis and earthquakes, and the need to secure emergency power sources.

[0043] Therefore, the power plant control device 210 in this embodiment is equipped with a reliability determination unit 220 shown by a dashed line in Fig. 2. The reliability determination unit 220 calculates the reliability of the power load equipment 230 and determines whether or not to output the above-mentioned equipment power consumption command DPB to the calculation amount adjustment unit 234 based on the calculated reliability. 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 Fig. 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.

[0044] 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 failures here include natural disasters such as earthquakes, tsunamis, and typhoons, and system failures such as power line failures and external power supply trips. Confidentiality, availability, and integrity are assumed as the reliability of the power load equipment 230, which is, for example, a data center.

[0045] "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 illustrated example, the reliability is set to low, assuming that human access is not possible in the event of such a natural disaster. On the other hand, in the event of a "system failure" or "external power supply failure," it is considered that there is no problem with human access, and the reliability is set to high.

[0046] "Availability" refers to the reliability of earthquake-resistant structures and secure private power generation. Regarding "disaster prevention structures," new regulatory design requirements have been established for earthquake, tsunami, and typhoon countermeasures for nuclear power plants after the earthquake. Therefore, the disaster prevention measures required for the installation of power load equipment 230 such as data centers have been realized, and therefore the reliability was determined to be high. Regarding "external power supply failure," the reliability was determined to be high because it does not change the physical structure of the power load equipment 230. When various anticipated failures occur, the utilization of "private power generation" is not considered an evaluation indicator. This is because, assuming "high reliability of the operation of power load equipment 230," private power generation is unnecessary in the event of a disaster.

[0047] Furthermore, "completeness" is an index of ensuring external complement 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 index of reliability.

[0048] 9 assumes a data center as the type of power load facility 230, but the reliability index may vary depending on the type of power load facility 230. By controlling the opening degree DP of the turbine bypass valve 302 and the facility power consumption PB only when the reliability of the power load facility 230 operating correctly is high based on this database, it becomes possible to operate the power load facility 230 while taking the reliability of the power load facility 230 into consideration.

[0049] Figure 10 is a flowchart of a control routine in the second embodiment. Like the routine in Figure 7, this routine also avoids the rapid all control rod insertion control 605 (see Figure 5) as much as possible after receiving a load shedding signal 501. In Figure 10, the processing of steps S30 to S34 and S36 to S40 is the same as the processing of steps S10 to S14 and S16 to S20 shown in Figure 7. However, if the determination in step S34 in Figure 10 is "Yes" (the power load equipment 230 can respond to the power reduction), the processing proceeds to step S35.

[0050] In step S35, the reliability determination unit 220 (see FIG. 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 FIG. 9), the power load equipment 230 has a reliability equal to or higher than a predetermined level. If the determination is "Yes," the power plant internal control device 210 opens the turbine bypass valve 302 in step S36.

[0051] In parallel with this, in step S40, the power plant control device 210 increases the processing load of the load computer 232. If the determination in step S35 is "No," the process proceeds to step S88. Here, the power plant control device 210 executes the reactor shutdown initiation process 601 and other processes shown in FIG. 6, and the process of this routine ends.

[0052] [Third Embodiment] Fig. 11 is a block diagram of a power transmission system 103 according to a third embodiment. The configuration of the power transmission system 103 is the same as that of the power transmission system 101 according to the first embodiment (see Fig. 2), except for the following points. First, the power transmission system 103 includes a central load control center 250 (control center), which is a control facility for the external power system 204. The central load control center 250 includes a central power control device 252. A calculation amount adjustment unit 234 of the power load facility 230 changes the facility power consumption PB of the power load facility 230 upon receiving a signal from the central power control device 252.

[0053] In the first embodiment described above, the generator output power, i.e., the generator output power PC, is temporarily reduced by controlling the opening of the turbine bypass valve 302. 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 opened." In this case, controlling the opening of the turbine bypass valve 302 is not enough to reduce the generator output power PC, and a scram occurs.

[0054] Therefore, it is considered advisable to adjust the external power transmission amount PA and the facility power consumption amount PB to appropriate values ​​in advance in preparation for an actual occurrence of a grid failure. However, reducing the external power transmission amount PA leads to a loss of power selling opportunities in 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 occurrence of a grid failure.

[0055] 12 is a diagram showing an example of a display screen 1200 displayed on the display of the central load dispatching device 252. The display screen 1200 includes a system diagram display unit 1201 and a system stability display unit 1202. The central load dispatching device 252 has a function of determining the content to be displayed on these displays by calculation. The system diagram display unit 1201 displays the configuration of the external power system 204. The system diagram display unit 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.

[0056] Furthermore, the system stability display unit 1202 displays the evaluation result of system stability when a system fault occurs in the power system of the system diagram display unit 1201. Here, the indicators include the generator phase difference, voltage, frequency, etc. The system stability display unit 1202 in Fig. 12 shows the evaluation result that voltage will drop when contingent fault case C3 occurs. Assuming this system fault, the central load dispatching device 252 adjusts the external power transmission amount PA and the facility power consumption PB so as to avoid a scram when the fault occurs.

[0057] 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 a command from the central power supply control device 252, they 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 index for changing the generator output power PC.

[0058] Fig. 13 is a waveform diagram of each part in the third embodiment. That is, Fig. 13 is a diagram schematically showing changes over time in the generator output power PC, which is the generator output power, the opening DP, which indicates the opening of the turbine bypass valve 302, and the equipment power consumption PB in the power load equipment 230, when the control of the third embodiment is performed. Here, for the opening DP and the equipment power consumption PB, the waveforms shown by solid lines are waveforms when the central load control device 252 has not detected any signs of abnormality, and the waveforms shown by dashed lines are waveforms when a sign of abnormality has been detected.

[0059] Assume that load shedding occurs at time t22. If a sign of an abnormality has been 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 sign of an abnormality has been detected). By performing the above operations, the equipment power consumption PB is increased only when there is a high possibility of load shedding or scram due to a grid failure, making it possible to reduce the opening degree DP of the turbine bypass valve 302 when load shedding occurs.

[0060] [Computer Configuration] FIG. 14 is a block diagram of a computer 980. The power plant control device 210, calculation amount adjustment unit 234, and central power supply command device 252 shown in FIGS. 2 and 11 each include one or more computers 980 shown in FIG. 14. In FIG. 14, the 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. 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 executes the control programs, etc. loaded from the SSD 982c to the RAM 982a to implement various functions. The interior of the power plant control device 210 shown in Figures 2 and 11 is primarily shown as blocks representing the functions implemented by the control programs, etc.

[0061] [Modifications] The present invention is not limited to the above-described embodiment, and various modifications are possible. The above-described embodiment is provided as an example to facilitate understanding of the present invention, and is not necessarily limited to an embodiment 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. Furthermore, it is 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 embodiment include, for example, the following.

[0062] (1) In each of the above embodiments, an example in which the nuclear power plant 201 is used as the power plant has been described. However, the power plant may be a thermal power plant or the like.

[0063] (2) In each of the above embodiments, the power plant control device 210 and the calculation amount adjustment unit 234 may be realized by the same computer.

[0064] (3) Since the hardware of the power plant control device 210, the calculation amount adjustment unit 234, the central power supply command device 252, etc. in the above embodiment can be realized by a general computer, the processes corresponding to the above-mentioned block diagrams and flowcharts, and programs for executing 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.

[0065] (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 an FPGA (Field Programmable Gate Array), etc.

[0066] (5) The various processes executed in the above embodiment may be executed by a server computer via a network (not shown), and the various data stored in the above embodiment may also be stored in the server computer.

[0067] Effect 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 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 to open the turbine bypass valve 302 based on the external power transmission amount PA and the equipment power consumption PB, so that scrams can be avoided as much as possible and the power plant (201) can be appropriately controlled.

[0068] Furthermore, it is more preferable that the power load equipment 230 includes a plurality of load computers 232, and the power load equipment adjustment unit (234) adjusts the equipment power consumption PB by adjusting the amount of calculation of the load computers 232. This allows the equipment power consumption PB to be adjusted according to the amount of calculation of the load computers 232.

[0069] 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 when the external power transmission amount PA at the time of load shedding 501, that is, the amount of external power transmission PA at the time of shedding, PA1, 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 larger than the amount of external power transmission at the time of shedding PA1.

[0070] 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 of 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.

[0071] 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 the 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. In this way, as the equipment power consumption PB increases, the generator output power PC can be increased accordingly.

[0072] Furthermore, it is more preferable that the turbine bypass valve control unit (212) adjusts the opening degree DP of the turbine bypass valve 302 so that the increase amount ΔPB per unit time of the equipment power consumption PB based on the equipment power consumption command DPB is equal to the increase amount ΔPC per unit time of the generator output power PC. This makes it possible to equalize the increase amount ΔPB per unit time of the equipment power consumption PB and the increase amount ΔPC per unit time of the generator output power PC.

[0073] Furthermore, as in the second embodiment, it is more preferable that 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 referring to reliability information 902 that defines the reliability according to a contingency failure of the power load equipment 230, and 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 affirmative. This allows the turbine bypass valve control unit (212) to transmit the equipment power consumption command DPB to the power load equipment adjustment unit (234) when the power load equipment 230 satisfies the predetermined reliability condition.

[0074] Furthermore, as in the second embodiment, it is more preferable that the reliability information 902 includes any one of confidentiality, availability, and 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.

[0075] Furthermore, as in the third embodiment, it is more preferable that the power load equipment adjustment unit (234) changes the amount of calculation of the load computer 232 in response to a command from a 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.

[0076] Furthermore, when the reducible power PV is smaller than the external power transmission amount PA1 at the time of interruption, it is more preferable that the power load equipment adjustment unit (234) sets the equipment power consumption PB to a value obtained by subtracting the reducible power PV from the external power transmission amount PA1 at the time of interruption. This allows the equipment power consumption PB to be set to an appropriate value.

[0077] Furthermore, when the power load equipment adjustment unit (234) changes the calculation amount 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 index for changing the generator output power PC. This makes it possible to change the generator output power PC in response to the state of the external power system 204.

[0078] 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 judgment 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 load dispatching center (dispatch 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 shutdown ΔPB Increase amount ΔPC Increase amount

Claims

1. A plant control device 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 plant control device comprising: a turbine bypass valve control unit that determines 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; and a power load equipment adjustment unit that adjusts the equipment power consumption.

2. The plant control device according to claim 1, characterized in that the power load equipment is equipped with a plurality of load computers, and the power load equipment adjustment unit adjusts the equipment power consumption by adjusting the amount of calculation of the load computers.

3. The plant control device according to claim 1, characterized in that, when a load shedding occurs in which the power generation plant is unable to transmit power to the external power grid, the turbine bypass valve control unit opens the turbine bypass valve if the external power transmission amount at the time of load shedding, which is the amount of external power transmission at the time of shedding, is smaller than the reduceable power, which is the amount by which the generator output power can be reduced by opening the turbine bypass valve.

4. The plant control device according to claim 2, characterized in that, when controlling the opening of the turbine bypass valve, the turbine bypass valve control unit transmits an equipment power consumption command to the power load equipment adjustment unit to instruct the equipment power consumption, and the power load equipment adjustment unit increases the amount of calculation of the load computer based on the equipment power consumption command, thereby increasing the equipment power consumption.

5. The plant control device according to claim 4, characterized in that the turbine bypass valve control unit increases the generator output power as the equipment power consumption increases by reducing 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.

6. The plant control device according to claim 5, characterized in that the turbine bypass valve control unit adjusts the opening of the turbine bypass valve so that the increase per unit time of the equipment power consumption based on the equipment power consumption command is equal to the increase per unit time of the generator output power.

7. The plant control device according to claim 4, further comprising a reliability determination unit that determines whether the reliability of the power load equipment in the event of an actual failure satisfies a predetermined reliability condition by referring to reliability information that defines the reliability according to an expected failure of the power load equipment, and wherein the turbine bypass valve control unit transmits the equipment power consumption command to the power load equipment adjustment unit when the determination result of the reliability determination unit is positive.

8. 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.

9. The plant control device according to claim 2, wherein the power load equipment adjustment 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.

10. The plant control device according to claim 3, characterized in that, when the reducible power is smaller than the amount of external power transmission during shutdown, 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 shutdown.

11. The plant control device according to claim 9, characterized in that when the power load equipment adjustment unit changes the calculation amount of the load computer in response to a command from the control center, it uses one of the generator phase angle difference between multiple generators included in the external power system, the voltage in the external power system, or the frequency in the external power system as a judgment index for changing the generator output power.

12. A plant control method for controlling a power plant comprising: 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 for supplying 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 plant control method comprising causing the computer to execute a turbine bypass valve control process for determining 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 process for adjusting the equipment power consumption.

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