Power control system, power control method, and power control program

Abstract

Providing technology that increases the possibility of discharging contracted electricity. [Solution] A power control system is configured that includes an activation command acquisition unit that acquires an activation command that is an instruction to perform reverse flow discharge to the power system, a dischargeable amount acquisition unit that acquires the dischargeable amount that each storage battery that performs the reverse flow discharge in accordance with the activation command can discharge during the reverse flow period in which the reverse flow discharge is performed, and a battery control unit that causes the storage batteries to perform the reverse flow discharge of the dischargeable amount during the reverse flow period at a predetermined output during a discharge period that is shorter than each of multiple unit periods that make up the reverse flow period.

Description

[Technical Field]

[0001] The present invention relates to a power control system, a power control method, and a power control program. [Background technology]

[0002] Electricity trading has been realized using the electricity trading market. Bidders fulfill their contracts by transmitting the contracted electricity from a predetermined power source to a grid or the like. Various systems are also known that enable the transmission of electricity traded through the market. For example, Patent Document 1 discloses a technology for calculating a predicted value of available electricity for a block of time, such as three hours, before the bidding deadline in a supply and demand balancing market. Specifically, Patent Document 1 discloses a technology for calculating the upper and lower limits of the remaining capacity expected at the start of the block to be bid, identifying scenarios in which the remaining capacity may be fully charged in the block and scenarios in which the remaining capacity may be depleted, and determining a reference value based on each scenario (Patent Document 1, paragraphs 0084 and 0085).

[0003] It is also disclosed that the suppliable power is determined by α+β based on the amount of power α corresponding to the lower limit of the remaining capacity at the start of the block and the power β by which the remaining capacity increases in a scenario where full charge can occur according to a reference value (Patent Document 1, 0088). Furthermore, other techniques for estimating the suppliable power for each block are known, such as Patent Document 2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-168659 [Patent Document 2] Japanese Patent Application Laid-Open No. 2025-73599 Summary of the Invention [Problem to be solved by the invention]

[0005] In markets such as capacity markets, where electricity to be discharged far into the future is traded, it has been difficult to estimate the amount of dischargeable electricity. Specifically, Patent Document 1 calculates the available electricity supply using the reference value for each block, a scenario, and the lower limit of the remaining capacity at the start of the block. However, it is difficult to predict electricity far into the future based on prior art. For example, in capacity markets, bids are submitted four years before the actual supply and demand year, and evaluations are conducted two years before the actual supply and demand year, requiring the fulfillment of various requirements. In this evaluation, it is necessary to prove that electricity can be discharged at the contracted output for the entire period to be discharged. Furthermore, when discharging electricity in response to an activation command, if the contracted output cannot be discharged for the entire period to be discharged, a penalty is incurred. It is not realistic to estimate the available electricity supply over such a long period based on Patent Document 1. Therefore, it is difficult to use prior art to fulfill requirements, and it is also difficult to use it to discharge electricity at the contracted output in the actual supply and demand year.

[0006] When evaluating power supply capacity or supplying power in response to a power activation command, it is important to discharge the contracted output power by making full use of power sources managed by the power company. Conventionally, there are technologies that enable the discharge of the contracted output power using power sources managed by the power company. For example, control is performed in which some of the multiple storage batteries are discharged at rated output during a part of the period when they should be discharged, and other parts of the multiple storage batteries are discharged at rated output during other parts of the period when they should be discharged.

[0007] However, with this type of control, it is difficult to determine which storage battery should be discharged during which period of the discharge period, making it difficult to efficiently use the power of multiple storage batteries, and it is also difficult to select a storage battery that will maintain discharge throughout the entire discharge period. The present invention has been made in consideration of the above-mentioned problems, and aims to increase the possibility of being able to discharge contracted power. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the power control system includes an activation command acquisition unit that acquires an activation command that is an instruction to perform reverse flow discharge to the power grid; a dischargeable amount acquisition unit that acquires a dischargeable amount that each of the storage batteries that performs the reverse flow discharge in accordance with the activation command can discharge during a reverse flow period in which the reverse flow discharge is performed; and a battery control unit that causes the storage batteries to perform the reverse flow discharge of the dischargeable amount during the reverse flow period at a predetermined output for a discharge period that is shorter than each of a plurality of unit periods that make up the reverse flow period.

[0009] That is, in the power control system, the amount of dischargeable power that the storage battery can discharge during a reverse flow period is distributed among multiple unit periods that make up the reverse flow period, and reverse flow discharge is performed. Furthermore, the period during which reverse flow discharge is performed within a unit period is a discharge period that is shorter than the unit period. With this configuration, the period during which reverse flow discharge is performed can be extended, albeit intermittently, compared to a configuration in which the length of the discharge period is the same as the length of the unit period. In the evaluation and actual supply and demand of electricity traded in the market, it is sometimes required that reverse flow discharge be performed throughout the entire predetermined reverse flow period, even if it is intermittent. The power control system can increase the likelihood that reverse flow discharge can be performed throughout the entire reverse flow period in such evaluation and actual supply and demand situations. Therefore, it is possible to increase the likelihood that contracted power can be discharged. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 illustrates a power control system. [Figure 2] This is a diagram showing events, periods, etc. that occur in chronological order along a time axis. [Figure 3] 3A and 3B are diagrams showing an example of conventional control of reverse power flow discharge. [Figure 4]4A and 4B are diagrams showing an example of conventional control of reverse power flow discharge. [Figure 5] 10 is a flowchart of a power control process. [Figure 6] 6A and 6B are diagrams illustrating an example of control of reverse power flow discharge. DETAILED DESCRIPTION OF THE INVENTION

[0011] Here, the embodiments of the present invention will be described in the following order. (1) Power control system configuration: (2) Power control processing: (3) Other embodiments:

[0012] (1) Power control system configuration: FIG. 1 is a diagram showing the configuration of a power control system 10. In FIG. 1, the transmission and reception of signals and information are indicated by solid lines or solid arrows, and the transmission and reception of power are indicated by dashed lines. In this embodiment, power can be supplied from a power grid 60 to a facility 50, such as a house owned by each of multiple consumers. The facility 50 is also equipped with a storage battery 50a and a solar power generation unit 50b. The solar power generation unit 50b includes a solar panel (not shown) and is capable of generating power using sunlight. The storage battery 50a is a secondary battery capable of storing power. In this embodiment, a user of the storage battery 50a can set a lower limit for the remaining charge of the storage battery 50a. For example, the user can set a lower limit for the remaining charge by operating a device in the facility 50 in order to reserve power for use in an emergency.

[0013] The power control system 10 is a computer used by a business operator that manages the charging and discharging of multiple storage batteries 50a. In this embodiment, the business operator procures power from various facilities connected to a power grid 60 and sells it to others. The business operator may be any entity, and in this embodiment, the business operator is an operator that provides activation command power sources in a capacity market. In addition, in this embodiment, the business operator supplies power from the power grid 60 to consumers and also purchases power from consumers. In other words, when an activation command is issued for power for which a bid has been made in the capacity market, the business operator purchases power from multiple consumers, controls the multiple storage batteries 50a to discharge the power, and supplies the power to the power grid 60. In this specification, power transmission from the storage batteries 50a to the power grid 60 is referred to as reverse power flow transmission.

[0014] Each consumer consumes the power supplied from at least one of the power grid 60, the solar power generation unit 50b, and the storage battery 50a. Therefore, when the consumer receives power from the power grid 60 and consumes it himself, he purchases the power from the business. On the other hand, when the amount of power generated by the solar power generation unit 50b is greater than the consumer's own power consumption, the power is stored in the storage battery 50a. When the surplus power stored in the storage battery 50a is transmitted in reverse power flow to the power grid 60, the consumer sells the power to the business.

[0015] The capacity market is a market for trading future supply capacity, and a business operator promises to supply a contracted output (kW) of power to the power grid 60 in response to an activation command, for example, in the actual supply and demand fiscal year four years from now. In this capacity market, the higher the output, the greater the business operator's income, so it is preferable for the business operator to contract for as large an output as possible. For this reason, a business operator may bundle multiple storage batteries 50a that it manages and submit a bid specifying the output that is predicted to be able to be supplied from the multiple storage batteries 50a.

[0016] However, to be recognized as a business operator bidding in the capacity market, various requirements must be met. The capacity market according to this embodiment trades electricity for the actual supply and demand year four years from now. When a business operator submits a bid, it must supply a predetermined output of electricity to the power grid 60 in the actual supply and demand year four years from now. If the business operator is unable to supply the predetermined output of electricity to the power grid 60 in the actual supply and demand year, a penalty is imposed on the business operator. Furthermore, an evaluation of the power supply capacity must be conducted two years prior to the actual supply and demand year, and the business operator must prove that it can supply electricity in response to an activation command. If the business operator fails to prove this, it loses its qualification as a business operator to supply electricity to the power grid 60 in the actual supply and demand year.

[0017] The evaluation of power supply capacity and the requirements for the actual supply and demand fiscal year include various items, such as supplying output in accordance with the capacity commitment contract. One of the requirements is whether or not power can be supplied for the entire reverse flow period. The reverse flow period is composed of multiple unit periods of predetermined length. Figure 2 is a diagram explaining the reverse flow period and unit periods. In Figure 2, events and periods that occur chronologically are shown along the time axis. Specifically, it is assumed that an activation command is issued at time ta. In this case, the reverse flow period Tr begins at time ts, a predetermined period T after time ta.

[0018] The length of the reverse flow period Tr is predetermined, and when this length of time has elapsed since time ts, the reverse flow period Tr ends at time te. The reverse flow period Tr is made up of multiple unit periods tu. The number and length of the unit periods tu are not limited, but in this embodiment there are six unit periods tu, and the unit period tu is 30 minutes long. Therefore, the length of the reverse flow period Tr is three hours.

[0019] Conventionally, various controls have been performed depending on the capacity of the storage battery 50a in order to supply power throughout the entire reverse flow period Tr. In this embodiment, the specifications (capacity and rated output) of the storage battery 50a installed in the facility 50 are not such that reverse flow discharge can be performed continuously at the rated output throughout the entire reverse flow period Tr. For example, assume that the storage battery 50a has a capacity of 6 kWh, which is its maximum charge amount, a rated output of 4 kW, which is its maximum output, and a reverse flow period Tr of 3 hours. If this storage battery 50a were charged to its maximum charge amount and reverse flow discharged at the rated output, the power would be depleted in 1.5 hours. Therefore, continuous reverse flow discharge at the rated output cannot be performed throughout the three-hour reverse flow period Tr.

[0020] 3A and 3B show an example of conventional control when reverse flow discharge is performed using such storage batteries 50a. In this example, it is assumed that the remaining charge of each storage battery 50a is 6 kWh, which is the maximum charge amount, and that each storage battery 50a is continuously reverse flow discharged at its rated output. In this case, each storage battery 50a can perform reverse flow discharge for 1.5 hours, so one storage battery 50a cannot supply power for the entire reverse flow period Tr. Therefore, the multiple storage batteries 50a are grouped into storage batteries 50a that perform reverse flow discharge for the first 1.5 hours of the reverse flow period Tr and storage batteries 50a that perform reverse flow discharge for the second 1.5 hours of the reverse flow period Tr. By performing reverse flow discharge at the rated output in the storage batteries 50a in each group, it is possible to achieve a state in which reverse flow discharge is performed for the entire reverse flow period Tr when viewed as a whole.

[0021] However, as shown in Figures 3A and 3B, selecting the storage batteries 50a is difficult when performing control such that reverse flow discharge is performed using some of the storage batteries 50a during some of the reverse flow periods Tr and reverse flow discharge is performed using the remaining storage batteries 50a during the remaining reverse flow periods Tr. Specifically, the dischargeable capacity of each of the multiple storage batteries 50a during evaluation or actual supply and demand may differ. Therefore, in order to perform reverse flow discharge during all of the unit periods tu that make up the entire reverse flow period Tr, it is actually necessary to create a discharge schedule that appropriately selects and combines the storage batteries 50a to be discharged and the periods during which they are discharged. Creating such a discharge schedule is generally difficult.

[0022] Furthermore, there is also a conventional technique for controlling each storage battery 50a so that power can be supplied throughout the entire reverse flow period Tr. FIGS. 4A and 4B are diagrams showing examples of control in this conventional technique. These examples assume that storage batteries 50a with the same specifications as those in the examples of FIGS. 3A and 3B are used. The control shown in FIGS. 4A and 4B assumes that the maximum charge amount of 6 kWh is continuously and evenly discharged throughout the entire reverse flow period Tr. In other words, the 6 kWh of power is evenly distributed over the three-hour reverse flow period Tr.

[0023] In this case, the output of the storage battery 50a is 2 kW, and reverse flow discharge is performed at 2 kW output in each of the six unit periods tu. With this type of control, the remaining charge of all the storage batteries 50a can be evenly distributed during the reverse flow period Tr, eliminating the need for complex processing such as selecting the storage battery 50a. However, with this control, the output of each storage battery 50a becomes relatively small, and the profits of the business operator are not increased. Furthermore, with this control, the output that can be supplied to the power grid 60 may become very small.

[0024] Specifically, the power stored in the storage battery 50a during the reverse flow period Tr is supplied to the power grid 60 and is also used for self-consumption by the user of the storage battery 50a. In Figures 4A and 4B, solid curves show examples of the output required for self-consumption. In these examples, the average output for self-consumption during the reverse flow period Tr is 1.2 kW. Therefore, if the output of the storage battery 50a during the reverse flow period Tr is 2 kW, the output of power that can be discharged through reverse flow will be 0.8 kW on average. This results in a very small output that can be supplied, and a very small supply capacity that businesses can bid for.

[0025] Therefore, in this embodiment, the power control system 10 is configured to create a discharge schedule that satisfies the requirement to supply power throughout the entire reverse flow period Tr while enabling the supply capacity to be increased.

[0026] Specifically, reverse flow discharge must be performed throughout the entire reverse flow period, but it is sufficient that there is a period in which reverse flow discharge is performed in all of the unit periods that make up the reverse flow period. In other words, the utility only needs to perform reverse flow discharge in each unit period, and the requirement is met even if there is a period in which reverse flow discharge is not performed in part of the unit period.

[0027] Therefore, the power control system 10 according to this embodiment has a function of creating a discharge schedule for the storage battery 50a so as to satisfy such requirements. To realize this function, the power control system 10 can communicate with devices in the facilities 50 to which multiple consumers belong via a network such as the Internet. The power control system 10 can issue control instructions to the devices in each facility 50 connected to the power control system 10 to control the storage battery 50a, thereby charging and discharging the storage battery 50a. The devices in the facilities 50 can also acquire information about the storage battery 50a, including its state of charge (SOC), and transmit the information including the SOC to the power control system 10. The control unit 20 can determine the remaining charge of the storage battery 50a based on the SOC. Furthermore, the control unit 20 can control the self-consumption devices present in the facility 50 to switch between a state in which self-consumption is possible and a state in which self-consumption is not possible.

[0028] The power control system 10 can also communicate with a relay server 70 and an activation command server 80 via a network such as the Internet. The relay server 70 can communicate with devices in the facilities 50 to which each of the multiple consumers belongs, and has the function of controlling the storage batteries 50a and self-consumption devices in the facilities 50. The relay server 70 receives instructions from the power control system 10, and in response to the instructions, issues control instructions to the storage batteries 50a in each facility 50 connected to the relay server 70, thereby charging and discharging the storage batteries 50a. The relay server 70 can communicate with devices in the facilities 50 and transmit information including the SOC of the storage batteries 50a installed in the facilities 50 to the power control system 10. Furthermore, the relay server 70 is present in the facility 50 and can control the self-consumption devices to switch between a state in which self-consumption is possible and a state in which self-consumption is not possible.

[0029] The activation command server 80 has a function of issuing an activation command to the power control system 10 used by a business operator in accordance with the power demand, when the business operator has submitted a bid in the capacity market and a contract has been concluded. That is, when power is needed in the power grid 60, the activation command server 80 issues an activation command to the power control system 10 a predetermined period T before the start time of the reverse flow period. The predetermined period T is not limited, but in this embodiment, the activation command is configured to be issued three hours before the start time of the reverse flow period. When an activation command is issued, the business operator causes the multiple storage batteries 50a managed by the business operator to reverse discharge power greater than or equal to the contracted output to the power grid 60.

[0030] The power control system 10 includes a control unit 20 including a CPU, RAM, ROM, etc., a storage medium 30, and a communication unit 40. The communication unit 40 is a device for communicating with devices within a facility 50, a relay server 70, and an activation command server 80.

[0031] The storage medium 30 records various programs and various data. In this embodiment, the storage medium 30 stores storage battery information 30a. The storage battery information 30a is information indicating the storage batteries 50a installed in the facility 50. In this embodiment, the storage battery information 30a includes identification information of the facility 50 in which each storage battery 50a is installed and information indicating the rated output of each storage battery 50a. The rated output is the maximum output value of the storage battery 50a. The control unit 20 can obtain the rated output of each storage battery 50a by referring to the storage battery information 30a.

[0032] The control unit 20 executes various programs stored in the storage medium 30 or ROM. The control unit 20 can execute a power control program as an example of such a program. When the power control program is executed, the control unit 20 functions as an activation command acquisition unit 20a, a dischargeable amount acquisition unit 20b, and a storage battery control unit 20c.

[0033] The activation command acquisition unit 20a has a function of acquiring an activation command, which is an instruction to execute reverse flow discharge to the power grid. Specifically, the control unit 20 monitors the presence or absence of an activation command sent by the activation command server 80 using the function of the activation command acquisition unit 20a. When an activation command is sent, the control unit 20 acquires the activation command via the communication unit 40. When the activation command is acquired, the control unit 20 identifies the reverse flow period, which is the period during which the activation command instructs reverse flow discharge. The length of the reverse flow period is predetermined, and is three hours in this embodiment. Furthermore, the power output to be supplied to the power grid 60 during the reverse flow period is predetermined based on the bids of businesses in the capacity market.

[0034] The dischargeable amount acquisition unit 20b has a function of acquiring the dischargeable amount that each storage battery that performs reverse flow discharge in response to an activation command can discharge during a reverse flow period when reverse flow discharge is performed. In this embodiment, the control unit 20 acquires the amount of power stored in the storage battery 50a at the start time of the reverse flow period and regards it as the dischargeable amount. The dischargeable amount may be acquired at any timing before the start time of the reverse flow period, but in this embodiment, the amount of power stored in the storage battery 50a at the start time of the reverse flow period is estimated at a timing after the activation command and a predetermined period before the start time of the reverse flow period.

[0035] Therefore, the control unit 20 acquires the SOC of each storage battery 50a via the communication unit 40 at a timing a predetermined period before the start time of the reverse flow period. The control unit 20 also determines the amount of power to be charged to the storage battery 50a by the solar power generation unit 50b during the predetermined period. The control unit 20 then adds the amount of power to be charged up to the start time of the reverse flow period to the remaining charge determined from the SOC, and determines this as the dischargeable amount.

[0036] The battery control unit 20c has a function of causing the storage battery to perform reverse flow discharge of the dischargeable amount during the reverse flow period by causing the storage battery to perform reverse flow discharge at a predetermined output during a discharge period that is shorter than each of the multiple unit periods that make up the reverse flow period. In this embodiment, the control unit 20 creates a discharge schedule for reverse flow discharge during the reverse flow period based on the dischargeable amount.

[0037] When creating the discharge schedule, the control unit 20 creates a discharge schedule such that, for each of the multiple unit periods that make up the reverse flow period, the storage battery performs reverse flow discharge at a predetermined output during a discharge period that is shorter than the unit period. Creating such a discharge schedule satisfies the requirement that power can be supplied throughout the entire reverse flow period. Although the requirement is met even if the length of the unit period and the length of the discharge period are the same, in this embodiment, the control unit 20 sets the discharge period so that the length of the discharge period is shorter than the unit period. This is because a configuration in which discharge occurs during a discharge period that is shorter than the unit period can increase the output of the storage battery 50a compared to a configuration in which the length of the discharge period is the same as the length of the unit period.

[0038] As described above, even if the charge amount of the storage battery 50a in this embodiment is at its maximum, reverse flow discharging at rated output does not allow continuous reverse flow discharging throughout the entire reverse flow period Tr. However, as in this embodiment, if the discharge period is set to be shorter than the unit period, reverse flow discharging can be performed during a discharge period, which is a portion of the entire unit period. With this configuration, reverse flow discharging cannot be performed continuously throughout the entire reverse flow period Tr, but the requirement can be met.

[0039] Furthermore, if the discharge period is shorter than the unit period, the default output, which is the output of the storage battery 50a during the discharge period, can be increased compared to a configuration in which the length of the discharge period is the same as the length of the unit period. Therefore, the output value that businesses can bid for can be increased compared to a configuration in which the length of the discharge period is the same as the length of the unit period.

[0040] Once the discharge schedule is determined, the power control system 10 controls each storage battery 50a during the reverse flow period Tr to perform reverse flow discharge at an output according to the discharge schedule. This control allows for a larger output during the discharge period compared to a configuration in which the length of the discharge period is the same as the length of the unit period. Furthermore, compared to a configuration in which the length of the discharge period is the same as the length of the unit period, the requirement that power can be supplied for the entire reverse flow period is met. This increases the likelihood that the contracted power can be discharged.

[0041] (2) Power control processing: Next, the power control process will be described in detail. FIG. 5 is a flowchart showing the power control process. The power control process is carried out after a business operator submits a bid in the capacity market. When the power control process is executed, the control unit 20 determines whether or not an activation command has been acquired using the function of the activation command acquisition unit 20a (step S100). That is, the control unit 20 monitors the presence or absence of an activation command transmitted from the activation command server 80 via the communication unit 40. If it is not determined in step S100 that an activation command has been acquired, the control unit 20 repeats the process of step S100.

[0042] If it is determined in step S100 that an activation command has been acquired, the control unit 20 considers the time when a predetermined period (e.g., three hours) has elapsed since the activation command as the start time of the reverse flow period Tr. The duration of the reverse flow period Tr is predetermined. If an activation command has been acquired, the control unit 20 uses the function of the dischargeable amount acquisition unit 20b to instruct all the storage batteries 50a to charge (step S105). That is, the control unit 20 instructs the devices in the facility 50 that can directly communicate with the power control system 10 to charge the storage batteries 50a via the communication unit 40. The control unit 20 also instructs the relay server 70 via the communication unit 40 to charge all the storage batteries 50a. In response to this instruction, the relay server 70 instructs the devices in the facility 50 connected to the relay server 70 to charge the storage batteries 50a.

[0043] When a charging command is issued, the facility 50 prohibits each storage battery 50a from consuming its own power. As a result, the storage battery 50a does not consume power, and is charged by at least one of the solar power generation unit 50b and the power grid 60. When the remaining charge of the storage battery 50a reaches the maximum value (SOC 100%), surplus power may be permitted to be consumed for private consumption. With the above configuration, the amount of dischargeable power from the storage battery 50a can be maximized after the activation command is issued.

[0044] Next, the control unit 20 acquires the dischargeable amount using the function of the dischargeable amount acquisition unit 20b (step S110). Specifically, the control unit 20 communicates with devices in the facility 50 or the relay server 70 via the communication unit 40 to acquire the SOC of each storage battery 50a. The control unit 20 also acquires the remaining charge of each storage battery 50a based on the SOC, and acquires the remaining charge at the start time of the reverse flow period Tr based on the charge amount per unit time of each storage battery 50a.

[0045] The timing for acquiring the dischargeable amount may be any timing after acquisition of the activation command and before the start of the reverse flow period Tr. In this embodiment, the dischargeable amount is acquired one hour before the start time of the reverse flow period Tr. Therefore, the control unit 20 acquires the dischargeable amount by adding the charge amount for one hour to the remaining charge at that timing. The charge amount per unit time may be acquired based on various methods. For example, it may be acquired based on the most recent charge amount history of the storage battery 50a, a weather forecast for a predetermined period from the present, a solar radiation forecast, the charge amount per unit time from the power grid 60, etc.

[0046] Next, the control unit 20 creates a discharge schedule using the function of the storage battery control unit 20c (step S115). In this embodiment, the control unit 20 creates the discharge schedule by specifying a discharge period during which the storage battery 50a is discharged in reverse power flow in each unit period and the output during the discharge period. In addition, a discharge schedule is created for each of the multiple storage batteries 50a.

[0047] Specifically, the control unit 20 divides the dischargeable amount acquired in step S110 by the default output to determine the length of the period during which reverse flow discharge can be performed at the default output of the storage battery 50a. In this embodiment, the default output is the rated output of the storage battery 50a. That is, in this embodiment, the control unit 20 determines the length of the period during which reverse flow discharge can be performed when reverse flow discharge is performed at the maximum output of the storage battery 50a. For example, if the dischargeable amount is 6 kWh and the rated output is 4 kW, the control unit 20 calculates 6 / 4 and determines that the length of the period during which reverse flow discharge can be performed is 1.5 hours. With the above configuration, it is possible to set a discharge schedule when the output of the storage battery 50a is maximized.

[0048] Next, the control unit 20 obtains the dischargeable ratio by dividing the duration of the period in which reverse flow discharge can be performed by the duration of the reverse flow period Tr. The dischargeable ratio is a value indicating the ratio of the duration of the period in which reverse flow discharge can be performed to the duration of the reverse flow period. In other words, the control unit 20 considers that reverse flow discharge can be performed at rated output for a period equivalent to the dischargeable ratio of the reverse flow period Tr. For example, if the duration of the period in which reverse flow discharge can be performed is 1.5 hours and the duration of the reverse flow period Tr is 3 hours, the dischargeable ratio is 1 / 2 (= 1.5 / 3).

[0049] The control unit 20 then multiplies the dischargeable rate by the length of the unit period to determine the length of the discharge period. For example, if the dischargeable rate is 1 / 2, the length of the discharge period is 1 / 2 of the unit period tu. FIG. 6A shows an example of a discharge period td for a storage battery 50a according to an example similar to that shown in FIGS. 3A and 4A. Here, it is assumed that the dischargeable rate is 1 / 2. In this case, the length of the discharge period td is 1 / 2 of the unit period tu. Note that a period within the unit period tu that is not the discharge period td of a given storage battery 50a is referred to as the standby period tw of that storage battery 50a.

[0050] The control unit 20 sets a discharge period td within each unit period tu and sets a discharge schedule so that reverse flow discharge is performed at rated output during the discharge period td. By performing reverse flow discharge during the discharge period td of the length determined as described above within each unit period, it is possible to satisfy the requirement to supply power throughout the entire reverse flow period Tr. Furthermore, the output of each storage battery 50a can be set to the rated output, which is the maximum output of the storage battery 50a.

[0051] According to the above process, it is possible to satisfy the requirement to supply power throughout the entire reverse flow period Tr, but in this embodiment, the system is further configured to reduce the period during which reverse flow discharging is not performed as much as possible within the unit period tu. In other words, the control unit 20 arranges the discharging periods of the multiple storage batteries 50a so that the discharging periods are dispersed within one unit period tu.

[0052] Various methods can be employed to distribute the discharge periods within the unit period tu. In this embodiment, the control unit 20 sets multiple discharge periods td included in each of the multiple unit periods tu so that there is no period that is not a discharge period td within the unit period tu. The control unit 20 also assigns multiple storage batteries 50a to each of the discharge periods td within the unit period tu and controls the storage batteries 50a assigned to the discharge periods td to perform reverse flow discharge. Specifically, the control unit 20 classifies the storage batteries 50a into N groups (N is an integer of 2 or greater). N may be determined by various methods as long as it is determined so that there is no period that is not a discharge period within the unit period tu when the discharge periods of the N groups are evenly distributed within the unit period. For example, if the dischargeable ratio is ½ or greater, N may be 2. Alternatively, a configuration example can be employed in which n is specified so that the dischargeable ratio is 1 / n (n is an integer of 2 or greater) or greater and smaller than 1 / (n-1), and n=N is set. 6A, the dischargeable ratio is 1 / 2, so the control unit 20 sets N to 2. Note that N may be an integer equal to or greater than n.

[0053] Furthermore, the control unit 20 defines the number of storage batteries 50a / N as the number of storage batteries 50a belonging to each group, and generates N groups of this number. That is, the control unit 20 associates information indicating one of the N groups with identification information of the storage batteries 50a. Furthermore, the control unit 20 arranges the N discharging periods td at regular intervals on the time axis and such that no periods other than discharging periods td occur within the unit period. That is, the control unit 20 evenly distributes the discharging periods td within the period from the start time to the end time of the unit period tu.

[0054] When the storage batteries 50a are classified into two groups as in the above example, the control unit 20 sets a discharging period td that starts at the same time as the start time of the unit period tu and a discharging period td that ends at the same time as the end time of the unit period tu. FIG. 6A shows the former discharging period td, and FIG. 6B shows the latter discharging period td. When the discharging periods td are set within the unit period tu, the control unit 20 associates N groups with the N discharging periods td, respectively. That is, the control unit 20 associates the storage batteries 50a belonging to each group with each discharging period td. For example, in the example shown in FIGS. 6A and 6B, half of the multiple storage batteries 50a are associated with the discharging period td that exists in the first half of the unit period tu as shown in FIG. 6A. Furthermore, the remaining half of the multiple storage batteries 50a are associated with the discharging period td that exists in the second half of the unit period tu as shown in FIG. 6B. In this configuration, the two discharge periods td shown in FIGS. 6A and 6B are spaced apart at a fixed interval (half the unit period tu) within the unit period tu. Because the discharge periods td are spaced apart without any gaps within the unit period tu, no period other than the discharge period td occurs within the unit period tu. In this way, the control unit 20 creates a discharge schedule so that the storage battery 50a associated with each discharge period td performs reverse power flow discharge at the rated output during each discharge period td.

[0055] Next, the control unit 20 determines whether the current time has reached the reverse flow start time using the function of the storage battery control unit 20c (step S120). That is, the control unit 20 acquires the current time using a timing circuit (not shown), and determines that the current time has reached the reverse flow start time if the current time is after the start time of the reverse flow period Tr. If it is not determined in step S120 that the current time has reached the reverse flow start time, the control unit 20 repeats step S120.

[0056] If it is determined in step S120 that the current time has reached the reverse flow start time, the control unit 20 sets the lower limit of the remaining charge of all the storage batteries 50a to 0 (step S125). That is, the control unit 20 adds an instruction to set the lower limit of the remaining charge of the storage batteries 50a to 0 to the discharge schedule created in step S115. When control is performed according to this discharge schedule, even if the user of the storage battery 50a has set a lower limit of the remaining charge, the setting of the lower limit is invalid during the reverse flow period Tr, and all of the power charged in the storage battery 50a can be discharged. Therefore, the amount of power discharged in the reverse flow can be increased compared to when the lower limit is set to a value greater than 0.

[0057] Next, the control unit 20, using the function of the battery control unit 20c, permits discharge from the storage battery 50a during the discharge period td and limits self-consumption (step S130). That is, the control unit 20 adds settings for the storage battery 50a and devices within the facility 50 that can self-consumer power to the discharge schedule created in step S115. Specifically, discharge from the storage battery 50a is permitted during the discharge period td. Furthermore, during the discharge period td, the operation of devices within the facility 50 that can self-consumer power is restricted more than during periods other than the discharge period td (e.g., periods other than the reverse flow period Tr and the standby period tw). This restriction may be achieved by suppressing power consumption in devices that can self-consumer power, such as air conditioners and water heaters, compared to periods other than the discharge period td. For example, these devices can be set to a low power consumption mode in which the amount of power consumed in response to user operation is reduced compared to normal power consumption, and the discharge schedule may be created so that the devices are set to the low power consumption mode during the discharge period td. The restriction on the occurrence of self-demand may include prohibition of the occurrence of self-consumption.

[0058] When control is performed according to the discharge schedule, the power of the storage battery 50a is mainly used for reverse flow discharge during the discharge period td. Therefore, the amount of power discharged in reverse flow can be increased compared to a configuration in which self-consumption using the power of the storage battery 50a is not limited.

[0059] Next, the control unit 20, using the function of the battery control unit 20c, prohibits discharge from the storage battery 50a during the standby period tw and permits self-consumption (step S135). Here, too, the control unit 20 adds settings for the storage battery 50a and devices within the facility 50 that may self-consume power to the discharge schedule created in step S115. Specifically, discharge from the storage battery 50a is prohibited during the standby period tw. Furthermore, operation of devices within the facility 50 that may self-consume power is permitted during the standby period tw. This permission means that the self-consumption restriction of step S130 is not imposed. In other words, self-consumption is not restricted, and each device is set to operate normally in response to user operation. If the restriction is realized in the low power consumption mode described above, in step S135, a mode is set in which power consumption is not restricted and the device operates at normal power consumption.

[0060] When control is performed according to this discharge schedule, power from the storage battery 50a is not consumed during the standby period tw. Therefore, when a device capable of self-consumption operates, power generated by the solar power generation unit 50b or power supplied from the power grid 60 is used. This prevents the power stored in the storage battery 50a from being used during the standby period tw. Furthermore, because the user can use the device during the standby period tw, which always exists within the unit period tu, it is possible to prevent the inconvenience of being unable to use the device continuously for the entire reverse flow period Tr.

[0061] Once the discharge schedule is determined by the above process, the control unit 20 executes control based on the discharge schedule (step S140). Specifically, the control unit 20 issues control instructions based on the discharge schedule via the communication unit 40 to devices in the facility 50 that can directly communicate with the power control system 10. The control unit 20 also outputs instructions to the relay server 70 via the communication unit 40 to control the devices in the facility 50 connected to the relay server 70. In other words, the control unit 20 controls the devices in the facility 50 connected to the relay server 70 to operate based on the discharge schedule.

[0062] When this control is performed, during the discharge period td, discharge from the storage battery 50a is permitted and self-consumption is restricted. Furthermore, during the standby period tw, discharge from the storage battery 50a is prohibited and self-consumption is permitted. Furthermore, the storage batteries 50a belonging to the groups associated with each discharge period td are controlled to perform reverse power flow discharge during each discharge period. Furthermore, when each storage battery 50a performs reverse power flow discharge, it is controlled to have a rated output.

[0063] (3) Other embodiments: The above embodiment is one example for implementing the present invention, and various other embodiments are also possible. For example, the power control system 10 may be realized by multiple devices, or may be configured to be realized by a cloud server or the like. Also, the storage battery 50a controlled via the relay server 70 may not be present. Furthermore, the power control system 10 may be realized by a device within the facility 50, such as a smart meter.

[0064] Furthermore, at least some of the activation command acquisition unit 20a, the dischargeable amount acquisition unit 20b, and the storage battery control unit 20c may be separated into multiple devices. Of course, some of the configurations in the above-described embodiments may be omitted, the order of the processes may be changed or omitted, or the process contents may be different. For example, the order of steps S125 to S135 may be interchanged. Also, a configuration may be adopted in which at least one of steps S125, S130, and S135 is omitted.

[0065] Furthermore, the storage battery 50a is not limited to a battery that charges with power generated by a solar power generation device. For example, it may be a storage battery mounted on a vehicle. Furthermore, the private power generation is not limited to solar power generation, but may be wind power generation, small hydroelectric power generation, biomass power generation, geothermal power generation, etc. Furthermore, the method for setting the discharge period td and the method for allocating the discharge period td are not limited to the above examples. For example, the length of the discharge period td does not have to be constant. An example of such a configuration is a configuration in which the unit period tu is divided into m equal parts (m is an integer equal to or greater than 2) and the process is repeated while changing the value of m. For example, two types of discharge periods td1 and td2 are set by dividing the unit period tu into two equal parts, td1 and td2, respectively, and a storage battery 50a is assigned to each of the two discharge periods td1 and the three discharge periods td2, and reverse power flow discharge is performed by the storage battery 50a assigned to each discharge period.

[0066] The activation command acquisition unit is only required to acquire an activation command that is an instruction to perform reverse flow discharge to the power grid. In other words, it is only required to acquire an activation command that is an instruction for a business that manages a storage battery to trade in the market and discharge contracted power through reverse flow. The business is not limited to a business that is registered as an activation command power source in the capacity market. For example, the business may be a business that is registered as another power source in the capacity market, or a business that trades in another market.

[0067] The power grid may be any facility capable of transmitting power to consumers and transmitting power from storage batteries, and there are no limitations on its type, size, etc. Of course, various facilities, such as power storage facilities and power plants, may be connected to the power grid. Reverse power flow may be any operation in which power is discharged from a storage battery to the power grid, and there are no limitations on the type of transmission network, etc.

[0068] The dischargeable amount acquisition unit may acquire the dischargeable amount that each storage battery that performs reverse flow discharge in response to the activation command can discharge during the reverse flow period during which reverse flow discharge is performed. That is, the dischargeable amount acquisition unit identifies the maximum amount of power that each storage battery can discharge during the reverse flow period. The dischargeable amount is the amount of power that can be discharged during the reverse flow period, and may be identified at the latest at the start of the reverse flow period, but may also be identified at any time between the activation command and the start of the reverse flow period.

[0069] The reverse flow period is a period during which reverse flow discharge should be performed, and may be predetermined for each market. However, the reverse flow period is made up of multiple unit periods. The length of the unit period is not limited and may be 30 minutes as described above, or may be a length other than 30 minutes. The dischargeable amount may be the amount of power that can be discharged during the reverse flow period, and may or may not match the remaining amount of power in the storage battery. The latter applies, for example, to cases where a lower limit on the amount of power is set by the user of the storage battery.

[0070] The battery control unit may perform reverse flow discharge of the dischargeable amount during the reverse flow period by causing the battery to perform reverse flow discharge at a predetermined output during a discharge period that is shorter than each of the unit periods that make up the reverse flow period. In other words, the battery control unit may perform reverse flow discharge during a discharge period that is a part of each unit period, rather than the entire unit period, thereby lengthening the time until the dischargeable amount of power is used up compared to when reverse flow discharge is performed over the entire unit period.

[0071] The default output is not limited to the rated output as in the above-described embodiment, and may be smaller than the rated output. For example, if the effective maximum value of the output is smaller than the rated output, the effective maximum value may be the default output. Alternatively, the default output may be smaller than the rated output to lengthen the discharge period. The discharge period may be shorter than each unit period constituting the reverse power flow period.

[0072] Furthermore, embodiments of the invention may be programs or methods. The above-described systems, programs, and methods may be realized as a single device or multiple devices, and include various aspects. They may also be modified as appropriate, such as being partly software and partly hardware. Furthermore, the invention may also be realized as a recording medium for a program that controls the system. Of course, the recording medium for the software may be a magnetic recording medium or a semiconductor memory, and any recording medium developed in the future may be considered in the same way. [Explanation of symbols]

[0073] 10...power control system, 20...control unit, 20a...activation command acquisition unit, 20b...dischargeable amount acquisition unit, 20c...storage battery control unit, 30...storage medium, 30a...storage battery information, 40...communication unit, 50...facility, 50a...storage battery, 50b...photovoltaic power generation unit, 60...power system, 70...relay server, 80...activation command server

Claims

1. an activation command acquisition unit that acquires an activation command that is an instruction to execute reverse power flow discharge to the power grid; a dischargeable amount acquisition unit that acquires a dischargeable amount that each of the storage batteries that performs the reverse flow discharge in response to the activation command can discharge during a reverse flow period in which the storage batteries perform the reverse flow discharge; a battery control unit that causes the storage battery to perform the reverse flow discharge of the dischargeable amount during the reverse flow period by causing the storage battery to perform the reverse flow discharge at a predetermined output during a discharge period that is shorter than each of a plurality of unit periods that constitute the reverse flow period; and A power control system comprising:

2. The battery control unit Dividing the dischargeable amount by the predetermined output, and further dividing the result by the length of the reverse flow period, multiplying the resultant dischargeable ratio by the length of the unit period to determine the length of the discharge period. The power control system of claim 1 .

3. The predetermined output is the rated output of the storage battery. The power control system according to claim 1 or 2.

4. The battery control unit a plurality of the discharge periods included in each of the plurality of unit periods are set so that there is no period that is not a discharge period within the unit period; assigning a plurality of the storage batteries to each of the discharge periods within the unit period, and controlling the storage batteries assigned to the discharge periods to perform the reverse power flow discharge; The power control system according to claim 1 or 2.

5. a user of the storage battery can set a lower limit of a remaining charge of the storage battery; the battery control unit disables the setting of the lower limit value during the reverse power flow period. The power control system according to claim 1 or 2.

6. The battery control unit During the discharging period, discharging from the storage battery is permitted, and the generation of private demand by a user of the storage battery is restricted more than during periods other than the discharging period; prohibiting discharge from the storage battery during a standby period that is a period other than the discharge period, and not restricting the generation of private demand by a user of the storage battery; The power control system according to claim 1 or 2.

7. an activation command acquisition step of acquiring an activation command which is an instruction to execute reverse power flow discharge to the power grid; a dischargeable amount acquisition step of acquiring a dischargeable amount that each of the storage batteries that performs the reverse flow discharge in response to the activation command can discharge during a reverse flow period in which the storage batteries perform the reverse flow discharge; a battery control step of causing the storage battery to perform the reverse flow discharge of the dischargeable amount during the reverse flow period by causing the storage battery to perform the reverse flow discharge at a predetermined output during a discharge period that is shorter than each of a plurality of unit periods that constitute the reverse flow period; A power control method comprising:

8. Computer, an activation command acquisition unit that acquires an activation command that is an instruction to execute reverse power flow discharge to the power grid; a dischargeable amount acquisition unit that acquires a dischargeable amount that each of the storage batteries that performs the reverse flow discharge in response to the activation command can discharge during a reverse flow period in which the storage batteries perform the reverse flow discharge; a battery control unit that causes the storage battery to perform the reverse flow discharge of the dischargeable amount during the reverse flow period by causing the storage battery to perform the reverse flow discharge at a predetermined output during a discharge period that is shorter than each of a plurality of unit periods that constitute the reverse flow period; A power control program that functions as a

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