Power management apparatus and program

Abstract

To reduce power cost.SOLUTION: A power management device 10 includes a transmission / reception unit 11 which communicates with a terminal which controls charge / discharge of a storage battery which is owned by a customer and stores generated electricity and is system-linked, and an instruction unit 13 which instructs the terminal by the transmission / reception unit 11 about charge / discharge so as to suppress reverse power flow and discharge within a range of forward power flow.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a power management device and a program. [Background technology]

[0002] In recent years, systems that generate electricity using natural energy such as solar power, charge cheap electricity at night into a storage battery, and then discharge the electrical energy stored in the storage battery to loads within the home for consumption have become widespread. For example, Patent Document 1 discloses a configuration including an isolated operation switching device that switches power transmission and reception between a grid, a power generation unit, a storage battery, and a residential load, and is connected to the grid and the residential load via a residential distribution board to which the grid and the residential load are connected. Patent Document 1 also discloses a configuration including a power conversion device that converts DC power from a storage battery to AC and outputs it to the residential load, and converts AC power from the isolated operation switching device to DC and charges the storage battery. Patent Document 1 also discloses a configuration that includes a control circuit that controls the output power of the power conversion device and controls the switching operation of the isolated operation switching device, and a housing that houses the power conversion device, the isolated operation switching device, and the control circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-129475 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to prevent a deterioration in the electricity sales balance when prices rise in the wholesale electricity market or when capacity contributions in the capacity market increase, retail electricity businesses implement demand response by changing the charging and discharging times of storage batteries to suppress customers' electricity demand. In addition, when connecting customers' storage batteries to the grid, reverse power flow must be allowed, but the purchase price for reverse power flow in the wholesale electricity market is low. Therefore, by controlling the charging and discharging of storage batteries to prevent reverse power flow, it is possible to reduce electricity costs. However, it is difficult to achieve a sufficient reduction in power costs with the techniques that have been proposed so far.

[0005] An object of the present invention is to solve such problems, and specifically to make it possible to reduce power costs compared to when the present invention is not applied. [Means for solving the problem]

[0006] To this end, the present invention provides a power management device that includes a communication means for communicating with a storage battery control unit that controls the charging and discharging of a storage battery that is connected to a grid and stores electricity generated by a customer, and an instruction unit that uses the communication means to instruct the storage battery control unit regarding charging and discharging so as to suppress reverse power flow and discharge within the range of forward power flow. Here, the instruction regarding charging and discharging by the instruction unit may include an instruction to select one of a plurality of management modes of the storage battery control unit. The instruction unit may instruct the setting of a switching mode, which is one of the management modes, for switching between a state in which the storage battery discharges by load following and a state in which the storage battery discharges by reverse power flow to a grid. The instruction unit may instruct the setting of a switching mode, which is one of the management modes, for switching between a state in which the storage battery is charged with only surplus generated power and a state in which electricity is purchased from the grid and charged. Another invention that achieves the above object is a program that enables an information processing device to implement a communication function for communicating with a storage battery control unit that controls the charging and discharging of a storage battery that is connected to a grid and stores electricity generated by a customer, and an instruction function that uses the communication function to give instructions to the storage battery control unit regarding charging and discharging so as to suppress reverse power flow and discharge within the range of forward power flow. [Effects of the Invention]

[0007] According to the present invention, it is possible to reduce power costs compared to a case where the present invention is not applied. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of the overall configuration of a power management system according to an embodiment of the present invention; [Figure 2] FIG. 2 illustrates an example of the hardware configuration of a power management apparatus and a terminal. [Figure 3] FIG. 2 illustrates an example of a functional configuration of a power management apparatus. [Figure 4] 10 is a flowchart illustrating an example of a process performed when a power management device remotely controls charging and discharging of a storage battery. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing an example of the overall configuration of a power management system 1 according to this embodiment. The power management system 1 shown in Fig. 1 is a system in which an electricity retailer remotely controls the charging and discharging of customers who have contracts with the electricity retailer. Each customer has a power receiving facility that receives electricity from the power grid and a power generating facility that has a solar cell module (PV (photovoltaics) module) that generates electricity using natural energy, such as sunlight. The term "retailer electricity supplier" refers to a retailer that procures electricity from power generation companies and supplies and sells it to consumers. Retailer electricity suppliers supply electricity to customers' homes, factories, etc. The term "electric power grid" as used here refers to a system that integrates power generation, transformation, transmission, and distribution to supply electricity to consumers' power receiving facilities.

[0010] In addition, each facility of multiple customers is connected to the grid, and consumes electricity received by the power receiving facility (forward flow), and can discharge electricity generated by the power generating facility to the power grid (reverse flow). Note that it is possible that the multiple customers include customers who do not perform reverse flow. The term "grid interconnection" here refers to connecting power generation facilities to the power grid of a power company. In the forward flow, the amount of power used is measured, and in the reverse flow, the amount of power sold to the power company is measured. Each customer is equipped with equipment necessary when the grid connection involves reverse power flow, such as a power conditioner that converts the DC power generated by the above-mentioned power generation equipment into AC power and adjusts the voltage and frequency, and a power sales meter that measures the amount of power sold.

[0011] <Configuration example of power management system 1> The power management system 1 according to the present embodiment includes a power management device 10 owned by an electricity retailer and a terminal 20 owned by a customer. The power management device 10 and the terminal 20 are connected to each other via a network 40.

[0012] The terminal 20 is installed in the building of a customer who has a contract with a retail electricity supplier. The terminal 20 is connected to a panel 21 installed on an indoor wall in the customer's building, for example, and a storage battery 30 installed indoors or outdoors.

[0013] The panel 21 is, for example, a touch panel that displays various information and accepts operational inputs from the user. The panel 21 may be a device other than a touch panel, and may have a configuration including a display unit and operation buttons. The panel 21 receives a predetermined mode through an operation input, and transmits the received mode to the terminal 20. The panel 21 also displays information received from the terminal 20. The predetermined modes include a charge mode, a discharge mode, a standby mode, and an automatic operation mode. Each mode will be described in detail later. The predetermined modes may also include modes other than these. For example, a specific mode that accepts remote control by the power management device 10.

[0014] The terminal 20 controls the charging and discharging of the customer's storage battery 30 based on control instructions from the power management device 10 and input instructions from the panel 21. The storage battery 30 is charged with some or all of the electricity generated by the power generation facility. The storage battery 30 can discharge electricity consumed by the customer's electrical devices and the like, as well as discharge electricity to the power grid. The storage battery 30 is connected to the grid. The storage battery 30 is a device that has the function of temporarily storing electricity. The storage battery 30 is a secondary battery that can be recharged and reused, such as a lead-acid battery, a nickel-metal hydride battery, a lithium-ion battery, or a NAS battery.

[0015] The terminal 20 acquires information indicating trends in power consumption of various electrical devices used by the customer. Based on the acquired information, the terminal 20 controls the storage battery 30. By controlling the storage battery 30 in this way, the forward power flow and reverse power flow described above are executed. In addition, if the customer's power generation facility is, for example, a solar power generation facility, the amount of power generated changes depending on the weather conditions of the day. Therefore, it is conceivable that the terminal 20 acquires information indicating the weather forecast for the location where the power generation facility is located and uses the information to control the storage battery 30.

[0016] The power management device 10 transmits a control signal to the customer's terminal 20. This control signal is a control instruction intended to reduce power costs such as electricity charges, and thereby remotely controls the forward and reverse power flows on the customer side. In addition, demand response (hereinafter referred to as DR) may be performed using a control signal to change the customer's electricity demand pattern. DR can be divided into up-DR, which increases demand, and down-DR, which decreases demand. Up-DR increases the amount of electricity received from the customer's electricity receiving equipment, while down-DR decreases the amount of electricity received from the customer's electricity receiving equipment.

[0017] The DR using the storage battery 30 will be described. Upward DR refers to, for example, charging the storage battery 30 with electricity received from the customer's power receiving equipment, thereby increasing the amount of power received by the power receiving equipment. In other words, upward DR charges the storage battery 30 with electricity received by the customer's power receiving equipment, rather than electricity generated by the customer's power generation equipment. In this way, upward DR is performed by changing the charging time of the storage battery 30. Downward DR refers to, for example, reducing the amount of power received by the power receiving equipment by discharging the storage battery 30 to meet the electricity used by the customer's electrical equipment. In other words, downward DR operates the customer's electrical equipment using electricity generated by the customer's power generation equipment, rather than electricity received by the customer's power receiving equipment. In this way, downward DR is performed by changing the discharge time of the storage battery 30.

[0018] The power management apparatus 10 is realized by, for example, an information processing device such as a computer. The power management apparatus 10 may be configured by a single computer, or may be realized by distributed processing using a plurality of computers.

[0019] Furthermore, the type of network 40 used to connect the power management device 10 and the terminal 20 is not particularly limited as long as it is capable of transmitting and receiving data. The network 40 may be, for example, the Internet, a local area network (LAN), a wide area network (WAN), etc. The communication line used for data communication may be wired or wireless. Furthermore, a configuration in which each device is connected via multiple networks 40 or communication lines may be used.

[0020] <Hardware configuration example> FIG. 2 is a diagram illustrating an example of the hardware configuration of the power management apparatus 10 and the terminal 20. As shown in FIG. 2, each of the power management apparatus 10 and the customer terminal 20 includes a central processing unit (CPU) 100a, which is a computing means, and a memory 100c, which is a main storage means. Each apparatus also includes external devices such as a hard disk drive (HDD) 100g, a network interface 100f, a display mechanism 100d, an audio mechanism 100h, and input devices 100i such as a keyboard and a mouse.

[0021] The memory 100c and the display mechanism 100d are connected to the CPU 100a via the system controller 100b. The network interface 100f, the magnetic disk drive 100g, the audio mechanism 100h, and the input device 100i are connected to the system controller 100b via the I / O controller 100e. Each component is connected by various buses such as a system bus and an input / output bus.

[0022] The magnetic disk device 100g stores programs for implementing various functions. These programs are loaded into the memory 100c, and the CPU 100a executes processes based on these programs, thereby implementing various functions.

[0023] Here, the electricity market includes the wholesale electricity market described above, in which the amount of electricity (kWh) actually generated is traded, and the capacity market described above, in which future supply capacity (kW) is secured. The wholesale electricity market is a trading market where electricity is traded as an energy source between the power generation sector and the retail sector. In the wholesale electricity market, the trading price of electricity fluctuates depending on the state of supply and demand for electricity. For example, wholesale electricity prices will rise if there is a domestic shortage of liquefied natural gas, which is used in thermal power generation, and power generation cannot be secured, or if the price of liquefied natural gas rises.

[0024] The capacity market is a market designed to ensure sufficient power generation capacity to meet future peak demand. The capacity market requires all retail electricity suppliers to contribute capacity contributions to power generation companies to encourage the construction and maintenance of power plants. Capacity contributions may vary depending on the winning bid price in the capacity market auction. Power sources that participate in the capacity market auction include stable power sources, variable power sources, and command-based power sources.

[0025] Of these, activation command power sources refer to power sources that have the following requirements: 12 activations per year, a 3-hour command response time, and a 3-hour duration after activation. When the supply and demand of electricity is tight, the storage battery 30 can participate in the capacity market as an activation command power source through DR, which reduces the amount of electricity used and increases the amount of electricity generated. When the supply and demand of electricity is tight, the value of electricity becomes relatively higher than usual, causing the market price to rise.

[0026] For these reasons, electricity retailers use upward and downward demand response (DR) to prevent a deterioration in their electricity sales balance when capacity contributions increase or wholesale electricity prices soar. Therefore, in the future, DR using reverse power flow will be necessary in addition to control based on wholesale electricity prices and capacity contributions, which have been utilized only with forward power flow. When considering transactions with the wholesale electricity market, reverse power flow from the storage battery 30 results in a low purchase price, so there is little benefit to the customer. If wholesale electricity prices rise significantly, there will be value for the business operators that purchase electricity from customers, but if not, there will be little value for the business operators.

[0027] Therefore, in this embodiment, the electricity retailer's power management device 10 (see FIG. 1) controls the charging and discharging of the customer's storage battery 30 (see the same figure) in the wholesale electricity market to prevent reverse power flow. This makes it possible to reduce the electricity cost of the electricity retailer compared to when a reverse power flow occurs due to a simple charge / discharge control command. In other words, when implementing downward DR control, it is desirable to avoid reverse power flow that is not commensurate with the electricity cost and to respond with forward power flow. However, when connecting to the grid, it is necessary to allow "reverse power flow." Therefore, in the wholesale electricity market, reverse power flow is not permitted.

[0028] <Functional Configuration of Power Management Apparatus 10> Next, the functional configuration of the power management apparatus 10 will be described. FIG. 3 is a diagram illustrating an example of the functional configuration of the power management apparatus 10. As shown in FIG. The power management apparatus 10 includes a transmitter / receiver 11, a determination unit 12, an instruction creation unit 13, and an instruction destination identification unit 14. The determination unit 12, the instruction creation unit 13, and the instruction destination identification unit 14 of the power management apparatus 10 are configured by a CPU 100a of the power management apparatus 10 (see FIG. 2).

[0029] The transmitting / receiving unit 11 is a network interface for connecting to a customer terminal 20 (see FIG. 1) via a network 40 (see the same figure). The transmitter / receiver 11 of the power management device 10 communicates with the terminal 20 using a predetermined protocol. The communication protocol used by the transmitter / receiver 11 can be ECHONET Lite (registered trademark), a communication standard established as a home network protocol for smart houses. This makes it possible to reduce development costs.

[0030] The determination unit 12 determines whether to issue an instruction to the terminal 20 (see FIG. 1) based on the status of the wholesale electricity market and the capacity market. That is, for example, when the wholesale electricity price in the wholesale electricity market rises sharply or there is a command to activate the capacity market, the determination unit 12 makes a determination accordingly. The determination unit 12 determines whether to issue an instruction for upward DR or downward DR in association with the execution of DR.

[0031] The instruction creation unit 13 creates an instruction to be sent to the customer's terminal 20 (see FIG. 1) according to the determination result of the determination unit 12. Such an instruction is the content of control for the customer's storage battery 30 (see FIG. 1). More specifically, the instructions to be created include predetermined modes, such as a charge mode, a discharge mode, a standby mode, and an automatic operation mode. These modes are standard for ECHONET Lite (registered trademark). These modes are acceptable to the panel 21 (see FIG. 1).

[0032] Here, the charging mode is a mode in which the storage battery 30 (see FIG. 1) is charged to increase the remaining capacity, and may be charged with electricity generated by a power generation facility or electricity received by a power receiving facility. The discharge mode is a mode in which the storage battery 30 discharges. In the discharge mode, if the power discharged from the storage battery 30 is greater than the power consumed by electrical devices, etc., a reverse power flow is performed for the difference in power. More specifically, a reverse power flow is performed by rated discharge in the discharge mode. The standby mode indicates that the battery 30 is not charging or discharging.

[0033] The automatic operation mode is a mode in which the terminal 20 automatically switches between charging and discharging the storage battery 30. More specifically, if the customer's power generation facility is a solar power generation facility, the charging and discharging modes of the storage battery 30 include charging at night and discharging during the day, and charging during the day and discharging at night. In the automatic operation mode, the terminal 20 estimates the amount of power generated and surplus power of the power generation facility based on weather forecasts and power consumption patterns. Then, in the automatic operation mode, the terminal 20 automatically switches between these two modes depending on the electricity rate and other factors set forth in the contract with the retail electricity supplier. The automatic operation mode periodically detects changes in the execution status and optimizes the charge and discharge control of the storage battery 30. In this way, the automatic operation mode leaves the charge and discharge of the storage battery 30 under the control of the terminal 20.

[0034] In the automatic operation mode, electricity generated by the power generation equipment is charged with that electricity, and the electricity is discharged within a range that follows the demand or load, which is the electricity consumed by electrical equipment, etc. In this way, the automatic operation mode discharges within the range of load following, and does not discharge at the rated level. In this respect, the automatic operation mode differs from the discharge mode, which discharges at the rated level.

[0035] As described above, in the automatic operation mode, discharge is performed in a load following manner, and therefore reverse power flow is not performed. In this respect, the automatic operation mode differs from the discharge mode in which reverse power flow may occur. Furthermore, in the automatic operation mode, although discharge is performed within the range of load following, electricity received by the power receiving equipment can be used when the remaining charge of the storage battery 30 is low or when the power consumed by electrical equipment, etc. is large. In other words, in the automatic operation mode, forward power flow may occur even when the storage battery 30 is discharging.

[0036] In the charging mode or the automatic operation mode, an upward DR can be performed by charging the storage battery 30 with electricity received at the customer's power receiving equipment. In the discharging mode or the automatic operation mode, a downward DR can be performed by reducing the amount of electricity received at the power receiving equipment.

[0037] The instruction destination specification unit 14 specifies the customer terminal 20 (see FIG. 1) to which the instruction is to be sent from among multiple customers. The specification criteria can include the area where the customer's power receiving equipment is located. Other specification criteria can include the amount of power generated by the customer's power generation equipment and the capacity of the storage battery 30 (see FIG. 1).

[0038] Here, the transmitter / receiver 11 of the power management device 10 is an example of a communication means, and the instruction creation unit 13 is an example of an instruction unit. The terminal 20 is an example of a storage battery control unit. The instruction created by the instruction creation unit 13 is an example of an instruction related to charging and discharging. The above-described charging mode, discharging mode, standby mode, and automatic operation mode are examples of multiple management modes possessed by the storage battery control unit. The automatic operation mode is an example of a state in which power is discharged by following the load, and the discharging mode is an example of a state in which power is discharged by reverse power flow to the grid. The automatic operation mode is an example of a state in which only surplus generated power is charged to the storage battery, and the charging mode is an example of a state in which electricity is also purchased from the grid and charged.

[0039] <Remote Control Processing of Power Management Apparatus 10> Next, a process performed when the power management device 10 remotely controls the charging and discharging of the storage battery 30 will be described. 4 is a flowchart showing an example of processing when the power management apparatus 10 remotely controls the charging and discharging of the storage battery 30. It is assumed that the terminal 20 is in a specific mode that accepts remote control by the power management apparatus 10. More specifically, the power management apparatus 10 transmits a setting signal for the specific mode to the terminal 20, causing the terminal 20 to transition to the specific mode. This specific mode is an example of a mode that can be switched.

[0040] In the example shown in Fig. 4, in the power management device 10, the determination unit 12 (see Fig. 3) determines whether the customer's storage battery 30 (see Fig. 1) should be charged (step 101). The determination unit 12 determines that charging should be performed, for example, when wholesale electricity prices are falling sharply, when electricity rates are low, or when upward DR is being implemented. Furthermore, if the customer's power generation facility is solar power generation, the determination unit 12 determines that charging should be performed at a predetermined time such as during the daytime when power generation increases.

[0041] When the determination unit 12 determines that charging is required (Yes in step 101), the instruction creation unit 13 (see FIG. 3) creates a charge mode instruction, which is an instruction to transition to a charge mode among the predetermined modes (step 102).

[0042] If charging is not required (No in step 101), the determination unit 12 (see FIG. 3) then determines whether the customer's storage battery 30 (see FIG. 1) should be discharged (step 103). The determination unit 12 determines that discharging should be performed, for example, when wholesale electricity prices are rising or when downward DR is being implemented. Furthermore, if the customer's power generation facility is a solar power generation facility, the determination unit 12 determines that discharging should be performed at a predetermined time, such as during the nighttime hours when the amount of power generation decreases.

[0043] When the judgment unit 12 judges that discharge should be performed (Yes in step 103), the instruction creation unit 13 (see FIG. 3) creates an automatic driving mode instruction, which is an instruction to transition to an automatic driving mode from among the predetermined modes (step 104). If discharge is not required (No in step 103), the process ends.

[0044] Here, when discharging is required, the automatic operation mode is instructed to be executed instead of the discharging mode. As described above, this is because the automatic operation mode, which discharges within the load following range, is selected to prevent reverse power flow in the wholesale electricity market. In the discharging mode, there is a possibility that reverse power flow may occur, as described above. In this way, the instruction generation unit 13 (see FIG. 3) generates an instruction for either the charging mode or the automatic driving mode.

[0045] The discharge mode is not used in the wholesale electricity market, but can be used when a downward demand response (DR) is executed to reverse power flow in response to a command to activate the capacity market. In this sense, the discharge mode is an example of a state in which power is discharged by reverse power flow to the grid. In the capacity market, the maximum number of times is 12 per year, and the discharge time is only 36 hours. Furthermore, reverse power flow in the capacity market is short and has a high unit price. Therefore, unlike in the wholesale electricity market, it becomes worthwhile to provide the reverse power flow of residential storage batteries to the capacity market. Therefore, when a command is issued in the capacity market, reverse power flow is performed in discharge mode.

[0046] When the instruction creation unit 13 creates an instruction (steps 102 and 104), the instruction destination identification unit 14 (see FIG. 3) identifies the instruction destination, which is the customer to whom the instruction is to be given (step 105). As described above, the identification of the destination may be based on, for example, the location of the customer, or on the amount of power generated by the customer's power generation facility or the capacity of the storage battery 30.

[0047] The transmitting / receiving unit 11 (see FIG. 3) transmits the instruction created by the instruction creating unit 13 to the destination identified by the destination identifying unit 14 (step 106). In this embodiment, the case where the instruction creation unit 13 creates a control instruction has been described, but it is also possible to select one of predetermined options. Such a selection can also be considered as creation of a control instruction.

[0048] Here, as described above, ECHONET Lite (registered trademark) can be used as the communication protocol for the transmitter / receiver 11, but this is not limiting. For example, it is also possible to use a unique protocol that transmits a remote discharge command together with information on whether or not to perform reverse power flow. Although this requires development costs, it allows for a design that is tailored to the usage environment.

[0049] According to this embodiment, when interconnected with the grid, reverse power flow is avoided by using either charging mode or automatic operation mode in the wholesale electricity market, thereby reducing electricity costs. Also, when responding to an activation command in the capacity market, the remuneration is a high unit price for a short time. Therefore, reverse power flow in the case of an activation command is performed in discharging mode, and the reverse power flow of the home storage battery is provided to the capacity market. In this way, reverse power flow when interconnected with the grid can be performed only when it is worth the power cost.

[0050] Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope of the above-described embodiments. It is clear from the claims that various modifications and improvements to the above-described embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0051] 10...power management device, 11...transmitter / receiver, 12...determination unit, 13...instruction creation unit, 14...instruction destination identification unit, 20...terminal, 21...panel, 30...storage battery, 40...network

Claims

1. a communication means for communicating with a storage battery control unit that controls charging and discharging of a storage battery owned by a customer and that stores generated electricity and is connected to a grid; an instruction unit that issues instructions regarding charging and discharging to the storage battery control unit via the communication means so as to suppress reverse power flow and discharge within the range of forward power flow; A power management device comprising:

2. The instruction regarding the charging and discharging by the instruction unit includes an instruction to select one of a plurality of management modes included in the storage battery control unit. The power management device of claim 1 .

3. the instruction unit instructs setting of a switching mode, which is a management mode included in the plurality of management modes and switches between a state of discharging by load following and a state of discharging by reverse power flow to the grid; The power management device of claim 2 .

4. the instruction unit instructs setting a switching mode, which is one of the management modes, for switching between a state in which only surplus generated electricity is charged to the storage battery and a state in which electricity is purchased from a grid and charged; The power management device of claim 2 .

5. In the information processing device, a communication function for communicating with a storage battery control unit that controls charging and discharging of a storage battery owned by the customer and that stores generated electricity and is connected to a grid; an instruction function that instructs the storage battery control unit via the communication function to charge and discharge the battery so as to suppress reverse power flow and discharge the battery within a range of forward power flow; A program to make this happen.

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