Power supply system

Abstract

To provide a power supply system capable of suitably exchanging a power by controlling a storage battery when a power failure occurs.SOLUTION: When a power failure occurs, a load-following storage battery 51 located on an upstream side functions as a system power supply in a pseudo manner, and when the power failure occurs, an EMS 80 sets a first mode in which charging and discharging control is performed on at least two or more of a plurality of accommodation storage batteries 50 among the plurality of accommodation storage batteries 50 located on a downstream side of the load-following storage battery 51 on the basis of an instruction of the EMS 80. Among the plurality of accommodation storage batteries 50, a second load following storage battery 52 located on the upstream side of at least two or more of the plurality of accommodation storage batteries 50 is set to a second mode in which the charge and discharge control is performed on the basis of the power flowing between a system power supply K and a load 10.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a technology for a power supply system including a plurality of storage batteries and a plurality of power generation units. [Background technology]

[0002] BACKGROUND ART Conventionally, a technology for a power supply system in which a plurality of storage batteries and a plurality of power generation units are provided between a system power supply and a load has been publicly known, as described in Patent Document 1, for example.

[0003] Patent Document 1 describes a power supply system in which a plurality of units each including a power storage device and a solar power generation device are connected to a power distribution line that connects a commercial power source and a load.

[0004] The power supply system described in Patent Document 1 includes a plurality of residential battery systems with storage batteries and power generation units installed on a distribution line connecting a grid power source and a load, and a shared battery system with storage batteries and power generation units installed upstream of the storage batteries of the residential battery systems. The storage batteries of the shared battery system perform load-following operation. This configuration allows the shared battery system to adjust the power surplus or shortage in the residential battery systems relative to the load, thereby, for example, reducing the power supply from the grid power source.

[0005] In this way, in the power supply system, by controlling each storage battery, it is possible to suppress the purchase of electricity and improve the self-consumption rate, and it is possible to suitably supply power from the power generation unit and storage batteries to the load.

[0006] However, the power supply system described in Patent Document 1 does not anticipate controlling the storage batteries in the event of a power outage. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-057150 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention was made in consideration of the above-mentioned situation, and the problem it aims to solve is to provide a power supply system that can optimally distribute power by controlling storage batteries in the event of a power outage. [Means for solving the problem]

[0009] The problem to be solved by the present invention is as described above, and the means for solving this problem will now be described.

[0010] That is, in claim 1, there is provided a power supply system comprising a plurality of storage batteries connected in series between a system power supply and a load, capable of charging power and supplying power to the load by discharging the charged power in both grid-connected operation under normal circumstances and standalone operation under power outages, a plurality of power generation units connected to the storage batteries and distributing generated power between the system power supply and the load, and a control unit capable of controlling charging and discharging of the plurality of storage batteries, wherein the plurality of storage batteries are capable of switching between the grid-connected operation and the standalone operation in accordance with power from the system power supply, and when a power outage occurs, a control unit controls the charging and discharging of the plurality of storage batteries by discharging power output by the standalone operation of an upstream storage battery located upstream of the plurality of storage batteries. The control unit is configured to configure a plurality of downstream storage batteries located downstream of the upstream storage batteries to perform the grid-connected operation based on the electric power, and when a power outage occurs, the control unit sets at least two or more first downstream storage batteries among the plurality of downstream storage batteries to a first mode in which charging and discharging are controlled based on instructions from the control unit, controls charging and discharging based on a result of comparing the total generated power obtained by adding up the amounts of power generated by the plurality of power generation units with the power consumed by the load, and sets a second downstream storage battery among the plurality of downstream storage batteries located upstream of the plurality of first downstream storage batteries to a second mode in which charging and discharging are controlled based on the electric power circulating between the system power source and the load.

[0011] In claim 2, the total generated power excludes the amount of power generated by the power generation unit corresponding to the upstream storage battery.

[0012] In claim 3, the control unit is capable of changing the charge / discharge conditions of the plurality of first downstream storage batteries based on the amount of electricity stored in the second downstream storage battery.

[0013] In claim 4, when the amount of stored electricity in the second downstream storage battery is less than a predetermined amount of stored electricity, the control unit changes the charging and discharging conditions of the plurality of first downstream storage batteries so that the amount of stored electricity in the second downstream storage battery is more likely to increase.

[0014] In claim 5, when the amount of stored electricity in the second downstream storage battery is equal to or greater than a predetermined amount of stored electricity, the control unit changes the charging and discharging conditions of the plurality of first downstream storage batteries so that the amount of stored electricity in the second downstream storage battery is more likely to decrease.

[0015] In claim 6, when the upstream storage battery is unable to output power through the independent operation, the second downstream storage battery among the plurality of downstream storage batteries is configured to output discharged power through the independent operation, and the control unit switches the first downstream storage battery among the plurality of first downstream storage batteries, which is located upstream, from the first mode to the second mode. [Effects of the Invention]

[0016] The present invention has the following effects.

[0017] In the present invention, when a power outage occurs, power can be appropriately supplied by controlling the storage battery. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a block diagram showing the configuration of a power supply system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram showing an example of a power supply mode. [Figure 3] FIG. 2 is a block diagram showing an example of a power distribution mode in a normal state. [Figure 4] FIG. 2 is a block diagram showing an example of a power distribution mode during a power outage. [Figure 5] 10 is a flowchart showing a main flow of interchange control. [Figure 6] FIG. 10 is a block diagram showing the division of storage batteries in the interchange control process during normal operation. [Figure 7] 10 is a flowchart showing a normal interchange control process. [Figure 8] 10 is a flowchart showing interchange control processing during a power outage. [Figure 9] FIG. 10 is a block diagram showing the division of storage batteries in interchange control processing during a power outage. [Figure 10] FIG. 10 is a block diagram showing an example of a power distribution mode when the remaining power storage capacity of the pseudo-grid storage battery is depleted during interchange control processing during a power outage. DETAILED DESCRIPTION OF THE INVENTION

[0019] A power supply system 1 according to one embodiment of the present invention will be described below with reference to FIGS.

[0020] The power supply system 1 supplies power from a power grid K or power generated using solar power to a load. In this embodiment, the power supply system 1 is applied to a residential block T (a collection of houses) made up of a plurality of detached houses (houses H). The residential block T includes a first house H1, a second house H2, a third house H3, ..., an Nth house HN as the plurality of houses H.

[0021] In a residential block T, an electricity retailer purchases electricity in bulk from an electric power company (grid power source K), and supplies (sells) the purchased electricity to each residence H as needed. Each residence H is equipped with an electrical appliance (load 10) that consumes electricity. The electricity supply system 1 can share the electricity purchased in bulk from the grid power source K and the electricity generated by each residence H using solar power among multiple residences H as needed.

[0022] The power supply system 1 includes a power path L, a switchboard 20, a power storage system 30, and an EMS80.

[0023] The power path L is a distribution line through which power flows. One side of the power path L is connected to a power grid K. The other side of the power path L is connected to a load 10 in each home H. In the following description, the side of the power path L that faces the power grid K in the direction of power flow may be referred to as the upstream side, and the side that faces the load 10 may be referred to as the downstream side.

[0024] The switching panel 20 switches the power distribution path as appropriate. The switching panel 20 is provided midway along the power path L. A plurality of switching panels 20 are provided, each corresponding to a power storage system 30 described later. Two distribution lines (a grid interconnection line La and an independent output line Lb) are provided between the switching panel 20 and the power storage system 30 corresponding to that switching panel 20. The grid interconnection line La is a distribution line used during grid-connected operation of the storage battery 50 described later. The independent output line Lb is a distribution line used during independent operation of the storage battery 50 described later.

[0025] In the switching panel 20, the grid interconnection line La is always connected to the power path L. The isolated output line Lb is provided downstream of the grid interconnection line La. The switching panel 20 is configured to be able to switch the power distribution path at the intersection P of the isolated output line Lb and the power path L depending on the distribution state of power from the upstream side.

[0026] Specifically, in a normal state (a state in which power is flowing from the upstream side of power path L), the switching panel 20 disconnects the independent output line Lb from the power path L, allowing power to flow between the upstream and downstream sides of the power path L via the intersection P. In a power outage state (a state in which power is not flowing from the upstream side of the power path L), the switching panel 20 connects the independent output line Lb to the power path L, allowing power to flow between the independent output line Lb and the power path L (see the switching panel 20 corresponding to the most upstream power storage system 30 in FIG. 3). In addition, when power is restored from the power outage state (when the normal state is restored), the switching panel 20 again disconnects the independent output line Lb from the power path L, allowing power to flow between the upstream and downstream sides of the power path L via the intersection P.

[0027] The power storage system 30 stores power from a power grid K and power generated using solar power, and outputs it to a power path L. In this embodiment, a plurality of power storage systems 30 are provided, each of which is owned by a home H. The plurality of power storage systems 30 are connected in series with each other in order from upstream to downstream with respect to the power path L. In this embodiment, the power storage systems 30 of a first home H1, a second home H2, a third home H3, ..., an Nth home HN are connected in series with each other in order from upstream to downstream. The power storage system 30 includes a solar power generation unit 40, a storage battery 50, and a power conditioner 60.

[0028] The solar power generation unit 40 is a device that generates electricity using sunlight. The solar power generation unit 40 is configured with a solar cell panel or the like. The solar power generation unit 40 is installed in a sunny location, such as on the roof of the house H. The power generated by the solar power generation unit 40 can be used to charge the storage battery 50.

[0029] The storage battery 50 charges and discharges power from the grid power supply K and power generated by the solar power generation unit 40. The storage battery 50 is configured, for example, with a lithium-ion battery. The storage battery 50 can perform grid-connected operation or independent operation depending on the status of the grid power supply K, etc. Details of the grid-connected operation and independent operation of the storage battery 50 will be described later. In this embodiment, the storage battery 50 has a maximum discharge amount (maximum amount of power that can be discharged per unit time) of 2000 (W). The storage battery 50 also has a maximum charge amount (maximum amount of power that can be charged per unit time) of 2000 (W). In preparation for a power outage, the storage battery 50 is set so that it will not discharge even if it is in a dischargeable state when the remaining amount of stored power falls below a predetermined threshold (for example, 30% of the capacity, hereinafter referred to as the "lower dischargeable limit value").

[0030] The storage battery 50 can perform various operations related to the control of charging and discharging of power. For example, the storage battery 50 can perform load following operation in accordance with the detection result of the power sensor Sb. The power sensor Sb is installed in the power path L immediately upstream of the switchboard 20 corresponding to the storage battery 50, and is configured to be able to detect the direction and magnitude of the power flowing through the installation location. When performing load following operation, the storage battery 50 discharges or charges an amount of power adjusted in accordance with the detection result of the power sensor Sb.

[0031] Specifically, when performing load following operation, if the power sensor Sb detects power flowing downstream (for example, if the supply of power to the load 10 is insufficient), the storage battery 50 discharges an amount of power corresponding to the detection result of the power sensor Sb. Also, if the power sensor Sb detects power flowing upstream (for example, if the power generated by the solar power generation unit 40 is surplus), the storage battery 50 charges an amount of power corresponding to the detection result of the power sensor Sb.

[0032] Furthermore, the storage battery 50 can also perform an operation specifically instructed by the EMS 80, which will be described later, instead of a load following operation. For example, the storage battery 50 can discharge or charge an amount of power specifically instructed by the EMS 80, which will be described later.

[0033] The storage battery 50 has a plurality of modes for charging and discharging power. The plurality of modes define the operation of the interchange storage battery 50 selected in the interchange control described below. In this embodiment, a first mode and a second mode are provided as the plurality of modes. The first mode and the second mode of the storage battery 50 are set (switched) by the EMS 80 described below.

[0034] When the first mode is executed, the storage battery 50 is in a state in which it can perform an operation instructed by the EMS 80, which will be described later. Specifically, when a discharge instruction is given, the storage battery 50 is in a state in which it can discharge, and goes into a discharging state or a standby state depending on the power demand of the load 10. When a standby instruction is given, the storage battery 50 goes into a standby state in which it does not charge or discharge. When a charge instruction is given, the storage battery 50 is in a state in which it can charge, and goes into a charging state or a standby state depending on its own remaining power storage amount and the amount of surplus power of the solar power generation unit 40.

[0035] In the first mode, when a discharge command or a charge command is issued, the storage battery 50 can discharge or charge by load following operation. Also, in the first mode, when a discharge command or a charge command is issued, the storage battery 50 can discharge or charge the amount of power specifically commanded by the EMS 80. Which operation the storage battery 50 will perform is set in advance by the EMS 80.

[0036] Furthermore, when the second mode is executed, the storage battery 50 controls charging and discharging through load following operation. That is, when the second mode is executed, the storage battery 50 discharges or charges the amount of power adjusted according to the detection result of the power sensor Sb.

[0037] The power conditioner 60 is a device that appropriately converts power (a hybrid power conditioner). The power conditioner 60 is configured to be able to output the power generated by the solar power generation unit 40 and the power discharged from the storage battery 50 to the power path L, and also to be able to output the power generated by the solar power generation unit 40 and the power from the grid power source K to the storage battery 50. The power conditioner 60 is connected to the power path L by the switch panel 20 via two distribution lines (a grid interconnection line La and an independent output line Lb). The power conditioner 60 is configured to be able to control the operation of the storage battery 50.

[0038] The EMS 80 is an energy management system that manages the operation of the power supply system 1. The EMS 80 includes a storage unit such as a RAM or a ROM, an arithmetic processing unit such as a CPU, an input / output unit such as an I / O, etc. The EMS 80 can perform predetermined arithmetic processing and storage processing, etc. The EMS 80 stores in advance various information and programs used when controlling the operation of the power supply system 1. The programs include a program related to interchange control, which will be described later.

[0039] As shown in Fig. 2, the EMS 80 is electrically connected (either wired or wirelessly) to the inverter 60 of each power storage system 30. The EMS 80 can acquire various information via the inverter 60, such as the operating status of the storage battery 50 (for example, the set mode, whether discharging is occurring, etc.), the remaining amount of stored power, the amount of discharged power, and the amount of chargeable power. The EMS 80 can also acquire various information via the inverter 60, such as the state of the power grid K (power outage state or normal state), the operating status of the solar power generation unit 40, and the amount of power generated. The EMS 80 may acquire the information directly from the storage battery 50 or the solar power generation unit 40, rather than via the inverter 60.

[0040] Furthermore, in the interchange control described below, the EMS 80 can appropriately determine (set) the mode of the storage battery 50 of each residence H and cause the storage battery 50 to execute the determined mode. Furthermore, when causing the storage battery 50 to execute the first mode, the EMS 80 can issue a discharge instruction, a charge instruction, or a standby instruction based on the acquired information, etc.

[0041] The EMS 80 is also electrically connected to the switchboard 20. The EMS 80 can control the operation of the switchboard 20.

[0042] The EMS 80 is also electrically connected to a power sensor Sa. The power sensor Sa is installed downstream of the switchboard 20, which is located at the most downstream side in the power path L, and upstream of all the loads 10, and is configured to be able to detect the direction and magnitude of the power flowing through the installation location. The EMS 80 can acquire the detection result of the power sensor Sa. The EMS 80 can also acquire the total amount of power consumed by all the loads 10 shown in B in FIG. 1 (hereinafter referred to as "total power consumption") based on the detection result of the power sensor Sa. In this way, the EMS 80 can issue a discharge instruction, a charge instruction, or a standby instruction based on the total amount of power generated by all the photovoltaic power generation units 40 shown in A in FIG. 1 (hereinafter referred to as "total power generation amount") and the total amount of power consumed by all the loads 10 shown in B.

[0043] Furthermore, based on the acquired information, etc., the EMS 80 can determine a discharge priority order (described later) for the storage battery 50. The discharge priority order is used mainly when the first mode is executed, and is the priority order for discharge among the storage batteries 50 in which the first mode is executed.

[0044] In setting the discharge priority order, it can be determined that the smaller the amount of discharge on the previous day, the higher the priority of the storage battery 50 in which the first mode is executed. Note that the discharge priority order is not limited to being determined based on the amount of discharge on the previous day, and can be determined based on various information.

[0045] Furthermore, based on the acquired information, etc., the EMS 80 can determine a charging priority order (described later) for the storage batteries 50. The charging priority order is used mainly when the first mode is executed, and indicates the charging priority order among the storage batteries 50 in which the first mode is executed.

[0046] In setting the charging priority, it can be determined that the lower the remaining amount of power stored in a storage battery 50 in which the first mode is executed, the higher the priority. Note that the charging priority is not limited to being determined based on the remaining amount of power stored, and can be determined based on various information.

[0047] The grid-connected operation or the independent operation of the storage battery 50 will be described in detail below with reference to FIGS.

[0048] Here, Fig. 3 shows an example of the power distribution mode in a normal state. Fig. 4 shows an example of the power distribution mode in a power outage state. For convenience of explanation, in Fig. 3 and Fig. 4, it is assumed that all solar power generation units 40 are not generating power and all storage batteries 50 are discharging.

[0049] The grid-connected operation of the storage battery 50 refers to operation performed while the storage battery 50 is connected to the grid power source K (i.e., in a normal state). During the grid-connected operation, the storage battery 50 can be charged with power from a power path L (for example, power from the grid power source K) via the inverter 60 while connected to the grid power source K. Furthermore, the storage battery 50 can output discharged power to the outside of the power storage system 30 via the inverter 60 while connected to the grid power source K. As shown in FIG. 3 , during the grid-connected operation, power is exchanged between the inverter 60 (the power storage system 30) and the power path L using the grid interconnection line La of the two distribution lines.

[0050] The storage battery 50 performs grid-connected operation when it is determined that it is in a state connected to the system power source K. In other words, even when there is actually a power outage, the storage battery 50 performs grid-connected operation when it is determined that it is in a normal state.

[0051] The independent operation of the storage battery 50 is an operation performed in a state independent of the grid power source K (i.e., in a power outage state). The storage battery 50 can determine whether it is in a power outage state or a normal state based on the power output from the power path L to the grid interconnection line La. When the storage battery 50 detects the occurrence of a power outage, it switches its operation from grid-connected operation to independent operation.

[0052] During the stand-alone operation, the storage battery 50 is independent of the grid power supply K and can output discharged power that has been independently output to the outside of the power storage system 30 via the inverter 60. As shown in Fig. 4, in the most upstream power storage system 30, during stand-alone operation, power is output from the inverter 60 (power storage system 30) to the power path L using the stand-alone output line Lb of the two distribution lines. Note that in the power outage state shown in Fig. 4, the power storage systems 30 other than the most upstream power storage system 30 determine that the storage battery 50 is in a normal state and perform grid-connected operation, as will be described later.

[0053] When the storage battery 50 detects the end of the power outage (power restoration from the power outage state), it switches its operation from independent operation to grid-connected operation.

[0054] With this configuration, the power storage system 30 can output power to the power path L regardless of whether it is in a normal state or a power outage. Furthermore, when a power outage occurs during a normal state, the switching panel 20 switches the state in which the independent output line Lb and the power path L cannot exchange power with each other to a state in which they can exchange power with each other. Thus, in this embodiment, even during a power outage, the discharged power of the storage battery 50 can be supplied to all of the loads 10 using the power path L.

[0055] In the power supply system 1 configured as described above, control is executed to suitably supply (interchange) the power purchased in bulk from the power company by the power retailer and the power generated by the solar power generation unit 40 of each power storage system 30 between the multiple homes H. This control is hereinafter referred to as "interchange control." In the power supply system 1 according to this embodiment, by executing the interchange control, power can be suitably interchanged in both normal and power outage states.

[0056] The interchange control executed by the EMS 80 will be described below with reference to FIGS.

[0057] In the following description, the power storage systems 30 of the first residence H1, the second residence H2, the third residence H3, ..., and the Nth residence HN may be referred to as the first power storage system 31, the second power storage system 32, the third power storage system 33, ..., and the Nth power storage system 3N, respectively. Similarly, the solar power generation units 40 of each power storage system 30 may be referred to as the solar power generation unit 41, the solar power generation unit 42, the solar power generation unit 43, ..., and the solar power generation unit 4N, respectively. Similarly, the storage batteries 50 of each power storage system 30 may be referred to as the storage battery 51, the storage battery 52, the storage battery 53, ..., and the storage battery 5N, respectively. Similarly, the power conditioners 60 of each power storage system 30 may be referred to as the power conditioner 61, the power conditioner 62, the power conditioner 63, ..., and the power conditioner 6N, respectively.

[0058] The flowchart shown in Fig. 5 is a main flow of the interchange control. The interchange control includes, as subroutines, an interchange control process during a power outage (see step S11) and an interchange control process during normal times (normal times) (see step S14), as will be described later. In the interchange control process during a power outage and normal times, the EMS 80 interchanges power between multiple houses H by controlling the storage battery 50. The interchange control is repeatedly executed by the EMS 80 at predetermined time intervals (for example, every minute).

[0059] In step S10, the EMS 80 determines whether or not there is a power outage at present. The EMS 80 acquires the state of the grid power supply K, for example, from the power conditioner 61 of the first power storage system 31 located most upstream (highest level). If the EMS 80 determines that there is a power outage at present (step S10: YES), it proceeds to processing in step S15. On the other hand, if the EMS 80 determines that there is no power outage at present (it is a normal state) (step S10: NO), it proceeds to processing in step S11.

[0060] In step S11, the EMS 80 determines whether power has been restored from a power outage. Specifically, the EMS 80 determines whether the current processing of step S11 is the first processing of step S11 after power has been restored from a power outage. That is, if the processing of step S10 before last determined that the current time is a power outage and the processing of step S10 after that determined that the current time is a normal state, the EMS 80 determines that the current processing of step S11 is the first processing of step S11 after power has been restored from a power outage.

[0061] In this way, when the EMS 80 determines that power has been restored from a power outage state (step S11: YES), it proceeds to the processing of step S12. On the other hand, when the EMS 80 determines that power has not been restored from a power outage state (i.e., the normal state continues) (step S11: NO), it proceeds to the processing of step S14.

[0062] In step S14, the EMS 80 executes interchange control processing during normal times. In the interchange control processing during normal times, all of the storage batteries 50 perform grid-connected operation. When executing interchange control processing during normal times, the EMS 80 first sets the second mode to the highest-order storage battery 51 (in the first storage system 31) among the storage batteries 50 in the multiple storage systems 30, and sets the first mode to the storage batteries 50 other than the highest-order storage battery 51 (i.e., all the storage batteries 50 downstream of the highest-order storage battery 51). Note that in FIG. 6, the storage battery 51 to which the second mode is set is classified as "group G1," and the other storage batteries 50 to which the first mode is set are classified as "group G2."

[0063] In the following, a storage battery set to the first mode may be referred to as an "interchange battery." A storage battery set to the second mode may be referred to as a "load following battery." In other words, when the normal interchange control process is started, one load following battery 51 is provided at the top, and other interchange batteries 50 (interchange batteries 52 to 5N) are provided.

[0064] The interchange control process (step S14) during normal times executed by the EMS 80 will be described below with reference to the flowcharts shown in FIGS.

[0065] In step S110, the EMS 80 determines whether the total power consumption is greater than the total power generation. If the EMS 80 determines that the total power consumption (see the range indicated by B in FIG. 6) is greater than the total power generation (see the range indicated by A in FIG. 6) (step S110: YES), the EMS 80 proceeds to processing in step S111. On the other hand, if the EMS 80 determines that the total power consumption is equal to or less than the total power generation (step S110: NO), the EMS 80 proceeds to processing in step S118.

[0066] In step S111, the EMS 80 calculates the discharge amount required for the storage battery 50 (hereinafter referred to as the "requested discharge amount") when the total power generation amount is insufficient for the total power consumption amount. The requested discharge amount is calculated by subtracting the total power generation amount from the total power consumption amount. The EMS 80 then proceeds to the process of step S112.

[0067] In step S112, the EMS 80 calculates the number of interchange storage batteries 50 to be discharged according to the requested discharge amount (hereinafter referred to as the "requested discharge number"). The requested discharge number is calculated by dividing the requested discharge amount by the maximum discharge amount of the interchange storage battery 50. The EMS 80 then proceeds to the processing of step S113.

[0068] Here, when the result of dividing the required discharge amount by the maximum discharge amount of the interchangeable storage battery 50 includes a decimal, the number of units requested to be discharged can be calculated by rounding up or down to the nearest integer. When the result is calculated by rounding up to the nearest integer, the total amount of power discharged by the interchangeable storage batteries 50 for the required number of units to be discharged becomes greater than the required discharge amount. When the above number of interchangeable storage batteries 50 are discharged, the supply of power from the system power source K and the load following storage battery 51 can be suppressed.

[0069] Furthermore, when calculations are made by rounding down decimal points, the total power discharged by the interchangeable batteries 50 for the number of units requested to be discharged is smaller than the requested amount of discharge. When the above number of interchangeable batteries 50 are discharged, the discharge power of the interchangeable batteries 50 alone is insufficient for the requested amount of discharge, and therefore a supply of power from the system power source K or the load following battery 51 is required, but such a supply of power can be minimized.

[0070] In the present embodiment, a predetermined threshold (hereinafter referred to as the "discharge feasibility threshold") is set in advance in the EMS 80 to determine whether to round up or round down the decimal point in the calculation. Specifically, when the remainder of the result of dividing the discharge request amount by the maximum discharge amount of the interchange storage battery 50 is equal to or greater than the discharge feasibility threshold, the EMS 80 rounds up the decimal point in the calculation. On the other hand, when the remainder of the result of dividing the discharge request amount by the maximum discharge amount of the interchange storage battery 50 is less than the discharge feasibility threshold, the EMS 80 rounds down the decimal point in the calculation. According to this, when the required discharge amount is relatively large, the number of interchange storage batteries 50 that perform discharging can be increased, and the discharge efficiency of the increased interchange storage batteries 50 can be improved. In the present embodiment, the discharge feasibility threshold is set to 1500 W.

[0071] After calculating the number of units to be discharged, the EMS 80 proceeds to the process of step S113.

[0072] In step S113, the EMS 80 calculates the number of interchangeable batteries 50 that can be discharged (hereinafter referred to as the "dischargeable number"). The dischargeable number is calculated as the total number of interchangeable batteries 50 whose remaining amount of stored electricity is equal to or greater than the dischargeable lower limit value, among all the interchangeable batteries 50. The EMS 80 then proceeds to the processing of step S114.

[0073] In step S114, the EMS 80 determines whether the number of units that can be discharged is equal to or greater than the number of units that need to be discharged. If the EMS 80 determines that the number of units that can be discharged is equal to or greater than the number of units that need to be discharged (step S114: YES), the EMS 80 proceeds to the processing of step S115. On the other hand, if the EMS 80 determines that the number of units that can be discharged is less than the number of units that need to be discharged (step S114: NO), the EMS 80 proceeds to the processing of step S116.

[0074] In step S115, the EMS 80 calculates the number of interchangeable batteries 50 to which a discharge instruction is to be given (hereinafter referred to as the "number of batteries to be instructed to discharge"). In step S115, the number of batteries requested to be discharged is set as the number of batteries to be instructed to discharge. The EMS 80 then proceeds to the processing of step S117.

[0075] In step S116, the EMS 80 calculates the number of units to be instructed to discharge. In step S116, the number of units that can be discharged is set as the number of units to be instructed to discharge. The EMS 80 then proceeds to the process of step S117.

[0076] In step S117, the EMS 80 issues a discharge instruction to the specified number of interchange storage batteries 50 in descending order of discharge priority. The EMS 80 also issues a standby instruction to the interchange storage batteries 50 for which a discharge instruction has not been issued. After the processing of step S117, the EMS 80 temporarily ends the interchange control processing during normal times.

[0077] As described above, if it is determined in step S110 that the total power consumption is equal to or less than the total power generation (step S110: NO), the EMS 80 proceeds to step S118, where it calculates the amount of power that is surplus to the total power consumption (hereinafter referred to as "total surplus power"). The total surplus power is calculated by subtracting the total power consumption from the total power generation. The EMS 80 then proceeds to processing in step S119.

[0078] In step S119, the EMS 80 calculates the number of interchangeable batteries 50 to be charged (hereinafter referred to as the "number of batteries requested to be charged") according to the total amount of surplus energy. The number of batteries requested to be charged is calculated by dividing the total amount of surplus energy by the maximum charge amount of the interchangeable batteries 50.

[0079] Here, when the result of dividing the total amount of surplus energy by the maximum charge amount of the interchangeable storage batteries 50 includes a decimal, the number of units requested to be charged can be calculated by rounding up or down to the nearest integer. When calculated by rounding down to the nearest integer, the total amount of surplus energy becomes greater than the total amount of energy charged to the interchangeable storage batteries 50 for the number of units requested to be charged. When the above number of interchangeable storage batteries 50 are charged, the supply of energy from the system power source K and the load following storage batteries 51 can be suppressed.

[0080] When calculated by rounding up decimal points, the total surplus energy amount is smaller than the sum of the energy charged to the interchangeable batteries 50 for the number of units requested to be charged. When the above number of interchangeable batteries 50 are charged, the total surplus energy amount alone is insufficient for the energy to be charged to the interchangeable batteries 50, and therefore it becomes necessary to supply energy from the system power source K or the load following battery 51, but it is possible to minimize such energy supply.

[0081] In the present embodiment, a predetermined threshold (hereinafter referred to as the "chargeability threshold") is set in advance in the EMS 80 to determine whether to round up or round down the decimal point in the calculation. Specifically, if the remainder of the result of dividing the total surplus energy amount by the maximum charge amount of the interchangeable storage batteries 50 is equal to or greater than the chargeability threshold, the EMS 80 rounds up the decimal point in the calculation. On the other hand, if the remainder of the result of dividing the total surplus energy amount by the maximum charge amount of the interchangeable storage batteries 50 is less than the chargeability threshold, the EMS 80 rounds down the decimal point in the calculation. According to this, when the required charge amount is relatively large, the number of interchangeable storage batteries 50 to be charged can be increased, thereby improving the charging efficiency of the increased interchangeable storage batteries 50. In the present embodiment, the chargeability threshold is set to 1000 W.

[0082] After calculating the number of vehicles requesting charging, the EMS 80 proceeds to the process of step S120.

[0083] In step S120, the EMS 80 calculates the number of interchangeable batteries 50 that can be charged (hereinafter referred to as the "chargeable number"). The chargeable number is calculated as the total number of interchangeable batteries 50 whose remaining amount of stored power is less than a predetermined value relative to the capacity (less than 100% in this embodiment). The EMS 80 then proceeds to the processing of step S121.

[0084] In step S121, the EMS 80 determines whether the number of chargeable vehicles is equal to or greater than the number of requested charging vehicles. If the EMS 80 determines that the number of chargeable vehicles is equal to or greater than the number of requested charging vehicles (step S121: YES), the EMS 80 proceeds to the processing of step S122. On the other hand, if the EMS 80 determines that the number of chargeable vehicles is less than the number of requested charging vehicles (step S121: NO), the EMS 80 proceeds to the processing of step S123.

[0085] In step S122, the EMS 80 calculates the number of interchangeable storage batteries 50 for which a charging instruction is to be given (hereinafter referred to as the "number of batteries to be instructed to be charged"). In step S122, the number of batteries to be requested to be charged is set as the number of batteries to be instructed to be charged. The EMS 80 then proceeds to the processing of step S124.

[0086] In step S123, the EMS 80 calculates the number of vehicles to be instructed to be charged. In step S122, the number of vehicles that can be charged is set as the number of vehicles to be instructed to be charged. The EMS 80 then proceeds to the process of step S124.

[0087] In step S124, the EMS 80 issues a charge instruction to the number of interchange storage batteries 50 for which a charge instruction has been issued, in descending order of charge priority. The EMS 80 also issues a standby instruction to the interchange storage batteries 50 for which a charge instruction has not been issued. After the processing of step S124, the EMS 80 temporarily ends the interchange control processing during normal times.

[0088] According to this process, power from the system power supply K and power generated by the solar power generation unit 40 of each power storage system 30 can be suitably shared among a plurality of homes H by control of the storage batteries 50 by the EMS80.

[0089] Furthermore, if the total power generation amount is insufficient for the total power consumption amount, the interchangeable storage battery 50 that belongs to group G2 and has been instructed to discharge can be discharged to make up for the power shortfall. Furthermore, if the total power generation amount is in excess of the total power consumption amount, the surplus power can be charged to the interchangeable storage battery 50 that has been instructed to charge. In this way, the power generated by the photovoltaic power generation unit 40 (total power generation amount) can be supplied to the load 10, thereby promoting self-consumption and ultimately improving the power self-sufficiency rate in the power supply system 1.

[0090] Furthermore, by issuing a discharge instruction in response to the discharge request amount starting from the interchangeable storage battery 50 with the highest discharge priority, it is possible to suppress imbalance in the discharge amount of the interchangeable storage batteries 50 of each residence H. That is, as in this embodiment, by determining that the interchangeable storage battery 50 with the smaller discharge amount on the previous day has the higher priority, it is possible to equalize the discharge amounts of the interchangeable storage batteries 50.

[0091] Furthermore, by issuing a charge instruction in response to a charge request amount starting from the interchangeable storage battery 50 with the highest charge priority, it is possible to suppress imbalance in the remaining amount of stored electricity among the interchangeable storage batteries 50 of each residence H. That is, as in this embodiment, by determining that the interchangeable storage battery 50 with the lowest remaining amount of stored electricity has a higher priority, it is possible to equalize the remaining amounts of stored electricity among the interchangeable storage batteries 50.

[0092] Furthermore, in this embodiment, the highest-order load following battery 51 is located upstream of the other interchangeable batteries 50, and charge and discharge are controlled by load following operation in accordance with the power flowing through the power path L, without being instructed to discharge, charge, or wait by the EMS 80. This allows the load following battery 51 to respond to sudden changes in the total amount of power consumption and the total amount of power generation, and makes it possible to suppress power supply from the system power source K and reverse power flow to the system power source K.

[0093] More specifically, depending on the interval at which the EMS 80 executes the interchange control, it may not be possible to respond to sudden changes in the total amount of power consumption or power generation by issuing only discharge instructions, charge instructions, or standby instructions to the interchange storage batteries 50 (interchange storage batteries 52 to 5N) belonging to group G2.

[0094] For example, if the total power consumption suddenly increases or the total power generation suddenly decreases, the discharge amount of the interchangeable battery 50 for which a discharge command has been issued may not be enough to cover the total power consumption, and power may be supplied from the system power supply K. However, because the load following battery 51 is located at the highest level, the amount of power that cannot be covered by the discharge amount of the interchangeable battery 50 for which a discharge command has been issued can be quickly discharged from the load following battery 51. In this way, the shortfall in power due to the sudden change can be covered by the discharge from the load following battery 51, and the power supply from the system power supply K can be suppressed.

[0095] Furthermore, if the total amount of power consumption suddenly decreases or the total amount of power generation suddenly increases, the charge amount of the interchangeable storage battery 50 for which a charge command has been issued may not be enough to charge the surplus power, and the surplus power may flow back to the grid power supply K. However, because the load following storage battery 51 is located at the highest level, the load following storage battery 51 can charge the amount of power (surplus power) that cannot be charged with the charge amount of the interchangeable storage battery 50 for which a charge command has been issued. In this way, the surplus power due to the sudden change can be absorbed by charging the load following storage battery 51, and the back flow to the grid power supply K can be suppressed.

[0096] In step S10 of FIG. 5, if the EMS 80 determines that the current time point is a power outage (step S10: YES), the EMS 80 proceeds to step S15, where it executes interchange control processing during a power outage.

[0097] Here, if normal interchange control processing is being executed when a power outage occurs, there is a problem that the operation of the load following battery 51 belonging to group G1 and the interchange battery 50 (interchange batteries 52 to 5N) belonging to group G2 becomes complicated. Explaining this in more detail, when a power outage occurs, all of the batteries 50 temporarily switch from grid-connected operation to independent operation. Then, when the top-level load following battery 51 starts independent operation, the discharged power independently output by the load following battery 51 is output to the power path L via the independent output line Lb (see FIG. 4).

[0098] When a power outage occurs in this way, the top-level load following battery 51 will play a pseudo role as the system power supply K in relation to the other interchangeable batteries 50. That is, when the discharged power independently output by the top-level load following battery 51 flows through the power path L to the load 10 side, the interchangeable batteries 50 belonging to group G2 will determine that power has been restored from the power outage state and will switch operation from independent operation to grid-connected operation (see FIG. 4).

[0099] When the interchangeable batteries 50 perform grid-connected operation in this manner, if the photovoltaic power generation unit 40 corresponding to the interchangeable batteries 50 belonging to group G2 generates surplus power, the surplus power from the photovoltaic power generation unit 40 may flow through power path L to the grid power supply K side. However, because the top-level load following battery 51 is operating in independent operation (determining that a power outage is occurring), if there is power flowing to the grid power supply K side, the load following battery 51 determines that there is a system abnormality and stops operation. When the load following battery 51 stops operation in this manner, the interchangeable batteries 50 belonging to group G2 determine that a power outage has occurred, and the interchangeable batteries 50 again switch operation from grid-connected operation to independent operation.

[0100] If the interchange control process during normal times is executed when a power outage occurs, there is a problem that the operation of each storage battery 50 (the load following storage battery 51 belonging to group G1 and the interchange storage battery 50 belonging to group G2) becomes complicated. Therefore, in the power supply system 1 according to this embodiment, interchange control process during a power outage is executed to prevent the operation of each storage battery 50 from becoming complicated when a power outage occurs and to interchange power between multiple houses H by controlling the storage batteries 50.

[0101] The interchange control process (step S15) executed by the EMS 80 during a power outage will be described below with reference to the flowchart shown in FIG. 8, and FIGS.

[0102] In this embodiment, when a power outage occurs, the normal interchange control process is executed (see step S14). Therefore, when the normal interchange control process is executed, the settings of the storage batteries 50 are such that one storage battery 50 belonging to group G1 is set as a load following storage battery 51, and the storage batteries 50 belonging to group G2 are set as interchange storage batteries 50 (interchange storage batteries 52 to 5N), as shown in FIG.

[0103] In addition, when a power outage occurs as described above, the load following batteries 51 belonging to group G1 will play a role of a pseudo system power supply K in relation to the interchange batteries 50 belonging to group G2. Therefore, in the following description, the load following batteries belonging to group G1 may be referred to as "pseudo system batteries" (see FIG. 9).

[0104] In step S210, the EMS 80 switches the mode of the interchange battery 50 provided next downstream from the pseudo-grid battery 51 (the load following battery 51 belonging to group G1) as viewed from the side of the grid power supply K, from the first mode to the second mode. In this manner, in this embodiment, of the multiple interchange batteries 50 belonging to group G2, the interchange battery 52 of the highest-order second power storage system 32 controls charging and discharging through load following operation.

[0105] In the following description, as shown in Fig. 9, the highest-ranking interchangeable battery 52 (switched from the first mode to the second mode) among the multiple interchangeable batteries 50 belonging to the group G2 as described above may be referred to as the "second load following battery 52." Also, as shown in Fig. 9, in the group G2, the second load following batteries 52 set to the second mode are classified as a "first group G2a," and the other interchangeable batteries 50 that remain set to the first mode are classified as a "second group G2b."

[0106] After the process of step S210, the EMS 80 proceeds to the process of step S211.

[0107] In step S211, the EMS 80 determines the remaining amount of stored power of the second load following storage battery 52. ​​That is, the EMS 80 acquires the remaining amount of stored power of the second load following storage battery 52 via the power conditioner 62 corresponding to the second load following storage battery 52. ​​Then, the EMS 80 determines the next process to proceed to based on the acquired remaining amount of stored power.

[0108] Specifically, the EMS 80 proceeds to the process of step S212 when the remaining amount of stored power of the second load following storage battery 52 is low (for example, less than 40%). On the other hand, the EMS 80 proceeds to the process of step S213 when the remaining amount of stored power of the second load following storage battery 52 is intermediate (neither high nor low) (for example, 40% or more and less than 80%). On the other hand, the EMS 80 proceeds to the process of step S214 when the remaining amount of stored power of the second load following storage battery 52 is high (for example, 80% or more).

[0109] In the processes of steps S212, S213, and S214, the EMS 80 changes preset parameters. Here, in this embodiment, the parameters are values ​​indicating the discharge permission threshold (see step S112) and the charge permission threshold (see step S119) used in the interchange control process during normal operation. The processes of steps S212, S213, and S214 will be described in detail later. After the processes of steps S212, S213, and S214, the EMS 80 proceeds to the process of step S215.

[0110] In step S215, the EMS 80 issues one of a charge instruction, a discharge instruction, and a standby instruction to the interchange batteries 50 (interchange batteries 53-5N) belonging to the second group G2b. Specifically, the EMS 80 replaces the pseudo grid battery 51 belonging to the group G1 with the grid power supply K in the normal state. Furthermore, the EMS 80 replaces the second load following battery 52 belonging to the first group G2a with the load following battery 51 belonging to the group G1 in the normal state. Furthermore, the EMS 80 replaces the interchange batteries 50 (interchange batteries 53-5N) belonging to the second group G2b with the interchange batteries 50 (interchange batteries 52-5N) belonging to the group G2 in the normal state. Then, in the state where the batteries have been replaced as described above, the EMS 80 executes the same processing as the interchange control processing in the normal state (see step S14).

[0111] In this case, the "total power generation amount" used by the EMS 80 in the processing of step S110 in the interchange control processing during normal times is not the amount indicated by A in Fig. 1 but the amount indicated by Aa in Fig. 9. That is, the interchange control processing during a power outage differs from the interchange control processing during normal times in that the amount of power generated by the photovoltaic power generation unit 41 corresponding to the pseudo-grid storage battery 51 belonging to group G1 is excluded from the total power generation amount. This makes it possible to prevent the power generated by the photovoltaic power generation unit 41 from being used for interchange to the load 10 together with the discharged power of the interchange storage battery 50, etc. After the processing of step S215, the EMS 80 temporarily ends the interchange control processing during a power outage.

[0112] According to this processing, the pseudo grid storage battery 51 performing the independent operation as described above plays a pseudo role of the grid power source K in relation to the storage batteries 50 belonging to the group G2 (the second load following storage battery 52 belonging to the first group G2a and the interchange storage battery 50 belonging to the second group G2b). Then, the storage batteries 50 belonging to the group G2 determine that power has been restored from a power outage state and switch operation from the independent operation to the grid-connected operation.

[0113] Here, the highest-order storage battery 50 among the multiple storage batteries 50 belonging to group G2 has been switched from the first mode to the second mode (changed from the interchange storage battery 52 to the second load following storage battery 52). Therefore, for example, when the photovoltaic power generation unit 40 corresponding to the interchange storage battery 50 belonging to the second group G2b generates surplus power, and when the surplus power of the photovoltaic power generation unit 40 flows through the power path L toward the system power source K, the second load following storage battery 52 can charge the power flowing toward the system power source K by load following operation. In other words, the second load following storage battery 52 can absorb the amount of power that cannot be charged with the charge amount of the interchange storage battery 50 for which a charge command has been issued (the surplus power), and therefore, reverse power flow toward the system power source K can be suppressed.

[0114] In this way, it is possible to prevent power from flowing to the pseudo-grid storage battery 51 operating independently, and therefore it is possible to prevent the pseudo-grid storage battery 51 from determining that there is a system abnormality and stopping operation. That is, in the interchange control process during a power outage, it is possible to prevent the operation of each storage battery 50 from becoming complicated when a power outage occurs, and to interchange power between multiple houses H by controlling the storage batteries 50.

[0115] The following describes the details of the processes in steps S212, S213, and S214.

[0116] As described above, in the interchange control process during a power outage, the second load following battery 52 absorbs the surplus power in the interchange battery 50 for which a charge command has been issued, thereby suppressing reverse power flow to the system power supply K. In other words, if the second load following battery 52 becomes fully charged and is no longer able to be charged, the second load following battery 52 will not be able to absorb the surplus power, which may undesirably result in reverse power flow to the system power supply K (pseudo system battery 51).

[0117] Furthermore, if the remaining amount of stored electricity in the second load following battery 52 falls below the lower limit of dischargeability (for example, 30% of the capacity), then, for example, if the total amount of power consumption suddenly increases or the total amount of power generation suddenly decreases, the second load following battery 52 will not be able to discharge, and the amount of discharge from the pseudo grid battery 51 will increase. Here, if the remaining amount of stored electricity in the pseudo grid battery 51 decreases, there is a possibility that the pseudo grid battery 51 will no longer be able to fulfill its role as a pseudo grid power source K, which is undesirable.

[0118] Therefore, in the interchange control process during a power outage, the parameters (discharge possibility threshold and charge possibility threshold) used to determine whether or not to charge or discharge the interchange storage battery 50 belonging to the second group G2b can be changed so that the second load following storage battery 52 can continue charging and discharging as much as possible.

[0119] That is, in step S212, the EMS 80 raises the discharge condition and lowers the charge condition. Specifically, the EMS 80 changes the discharge possibility threshold from the normal 1500 W to 1000 W. The EMS 80 also changes the charge possibility threshold from the normal 1000 W to 1500 W.

[0120] According to this, when the remaining amount of stored power in the second load following battery 52 is low, even if the remainder (i.e., the required amount of discharge) obtained by dividing the requested discharge amount by the maximum amount of discharge of the interchange battery 50 is not that large, it is possible to make it easier to increase the number of interchange batteries 50 that are being discharged that belong to the second group G2b. Also, even if the remainder (i.e., the required amount of charge) obtained by dividing the total amount of surplus power by the maximum amount of charge of the interchange battery 50 is large, it is possible to make it harder to increase the number of interchange batteries 50 that are being charged that belong to the second group G2b. In other words, when the remaining amount of stored power in the second load following battery 52 is low, it is possible to prevent the remaining amount of stored power in the second load following battery 52 from decreasing any further, and make it easier to increase it.

[0121] In step S214, the EMS 80 lowers the discharge condition and raises the charge condition. Specifically, the EMS 80 changes the discharge possibility threshold from the normal 1500 W to 1800 W. The EMS 80 also changes the charge possibility threshold from the normal 1000 W to 700 W.

[0122] According to this, when the remaining amount of stored power in the second load following battery 52 is large, even if the remainder (i.e., the required amount of discharge) obtained by dividing the requested discharge amount by the maximum amount of discharge of the interchange battery 50 is large, it is possible to make it difficult to increase the number of interchange batteries 50 that are being discharged that belong to the second group G2b. Also, even if the remainder (i.e., the required amount of charge) obtained by dividing the total amount of surplus power by the maximum amount of charge of the interchange battery 50 is not so large, it is possible to make it easy to increase the number of interchange batteries 50 that are being charged that belong to the second group G2b. In other words, when the remaining amount of stored power in the second load following battery 52 is large, it is possible to suppress any further increase in the remaining amount of stored power in the second load following battery 52 and make it easier for the remaining amount of stored power to decrease.

[0123] In step S213, if the parameters have been changed by the processing in step S212 or step S214, the EMS 80 changes the parameters to the values ​​(initial values) before the change. Specifically, the EMS 80 returns the discharge possibility threshold to the normal value of 1500 W. The EMS 80 also returns the charge possibility threshold to the normal value of 1000 W.

[0124] According to this, when the remaining amount of electricity stored in the second load-following storage battery 52 is neither large nor small, the discharge possibility threshold and the charge possibility threshold can be set to the initial value (the same value as the normal interchange control processing) to determine the number of interchange storage batteries 50 to be charged or discharged.

[0125] Thus, the processes of steps S212, S213, and S214 can prevent the second load following battery 52 from becoming fully charged and being unable to charge any more, and can prevent reverse power flow to the pseudo grid battery 51. In addition, it can prevent the second load following battery 52 from being unable to discharge, which can prevent the remaining amount of stored power in the pseudo grid battery 51 from decreasing, and can prevent the pseudo grid battery 51 from being unable to fulfill its role as a pseudo grid power source K.

[0126] 5, if it is determined that power has not been restored from a power outage (i.e., the normal state continues) (step S11: NO), the EMS 80 returns the parameters to their normal values ​​in the process of step S12. That is, if the parameters have been changed by the processes of steps S212 and S214, the EMS 80 changes the parameters to their values ​​before the change (initial values). The EMS 80 then proceeds to the process of step S13.

[0127] In step S13, the EMS 80 changes the setting of each storage battery 50. Specifically, by the processing of step S210, the EMS 80 switches the mode of the storage battery 50 (second load following storage battery 52) provided next downstream of the pseudo-grid storage battery 51 (load following storage battery 51 belonging to group G1) from the second mode to the first mode. In this way, the setting of each storage battery 50 becomes the same as when the normal interchange control processing is executed. The EMS 80 then executes the normal interchange control processing (step S14) as described above, and then temporarily ends the main flow of the interchange control.

[0128] Note that when the interchange control process during a power outage is executed as shown in FIG. 9 , if the pseudo grid battery 51 becomes unable to discharge due to a decrease in the remaining amount of stored electricity, the pseudo grid battery 51 cannot fulfill the role of pseudo grid power supply K. In such a case, as shown in FIG. 10 , the second load following battery 52 provided next downstream from the pseudo grid battery 51 fulfills the role of pseudo grid power supply K. In the following description, the second load following battery 52 is referred to as the “second pseudo grid battery 52.” That is, when the discharged power independently output from the second pseudo grid battery 52 flows through the power path L to the load 10 side, the interchange battery 50 belonging to the second group G2b that had once started independent operation determines that power has been restored from the power outage state and switches operation from independent operation to grid-connected operation.

[0129] In this case, the EMS 80 switches the mode of the highest-order interchange battery 50 (interchange battery 53 in this embodiment) among the multiple interchange batteries 50 belonging to the second group G2b from the first mode to the second mode. In the following description, the interchange battery 53 whose mode has been switched will be referred to as the "third load following battery 53." In this way, by controlling the interchange batteries 50 (interchange batteries 54 to 5N) located downstream of the third load following battery 53, the EMS 80 can prevent reverse power flow from occurring and complicating the operation of each battery 50, and can also interchange power between the multiple homes H. In this way, the EMS 80 can transfer the role of the grid-connected battery or the load following battery to the downstream batteries 50 one by one, depending on the remaining power storage capacity of each battery 50.

[0130] 10, when the remaining amount of stored electricity in the pseudo-grid storage battery 51 increases to a level that allows discharge, the EMS 80 can return to the state shown in Fig. 9 by, for example, changing the mode of each storage battery 50. Furthermore, when the state shown in Fig. 10 is reached, the EMS 80 can reliably charge the pseudo-grid storage battery 51 with the electricity generated by the solar power generation unit 41 by disconnecting the first power storage system 31 from the switch panel 20 corresponding to the first power storage system 31.

[0131] As described above, in the power supply system 1 according to this embodiment, a plurality of storage batteries 50 connected in series between a system power supply K and a load 10, capable of charging with power and discharging the charged power in both normal grid-connected operation and stand-alone operation during a power outage, thereby supplying power to the load 10; a plurality of solar power generation units 40 (power generation units) connected to the storage battery 50 and distributing generated power between a system power supply K and the load 10; an EMS80 (control unit) capable of controlling charging and discharging of the plurality of storage batteries 50; A power supply system comprising: The plurality of storage batteries 50 include: The system is configured such that the grid-connected operation and the independent operation can be switched in accordance with the power from the system power source K, and in the event of a power outage, the multiple interchangeable batteries 50 (interchangeable batteries 52 to 5N, downstream batteries) located downstream of the load-following battery 51 (upstream battery) located upstream of the multiple storage batteries 50 perform the grid-connected operation based on the discharge power output by the independent operation of the load-following battery 51 (upstream battery), The EMS 80 (control unit) In the event of a power outage, Among the plurality of interchangeable batteries 50 (interchangeable batteries 52 to 5N, downstream side batteries), at least two or more interchangeable batteries 50 (interchangeable batteries 53 to 5N, first downstream side batteries) A first mode is set to control charging and discharging based on an instruction from the EMS 80 (control unit), Controlling charging and discharging based on a result of comparing a total power generation amount obtained by adding up the amounts of power generated by the plurality of solar power generation units 40 (power generation units) with the power consumption consumed by the load 10; Among the plurality of interchangeable batteries 50 (interchangeable batteries 52 to 5N, downstream side batteries), a second load following battery 52 (second downstream side battery) located upstream of the plurality of interchangeable batteries 50 (interchangeable batteries 53 to 5N, first downstream side batteries) A second mode is set in which charging and discharging are controlled based on the power flowing between the system power supply K and the load 10.

[0132] With this configuration, in the event of a power outage, the storage battery 50 can be controlled to appropriately accommodate power. Specifically, since it is possible to prevent power from flowing to the pseudo-grid storage battery 51 that is operating independently, it is possible to prevent the pseudo-grid storage battery 51 from determining that there is a system abnormality and stopping operation. In other words, in the interchange control process during a power outage, it is possible to prevent the operation of each storage battery 50 from becoming complicated when a power outage occurs, and to interchange power between multiple houses H by controlling the storage batteries 50.

[0133] In addition, in the power supply system 1, The total generated power does not include the amount of power generated by the solar power generation unit 41 (power generation unit) corresponding to the load following storage battery 51 (upstream storage battery).

[0134] With this configuration, it is possible to prevent the power generated by the solar power generation unit 41 (power generation unit) from being used for interchange with the load 10 together with the discharged power of the interchange storage battery 50 and the like.

[0135] In addition, in the power supply system 1, The EMS 80 (control unit) The charging and discharging conditions of the plurality of interchangeable batteries 50 (interchangeable batteries 53 to 5N, first downstream battery) can be changed based on the amount of electricity stored in the second load following battery 52 (second downstream battery) (see steps S212, S213, S214).

[0136] This configuration prevents the pseudo system storage battery 51 from being unable to fulfill its role as a pseudo system power source K, and also prevents surplus power from flowing back toward the system power source K (pseudo system storage battery 51).

[0137] In addition, in the power supply system 1, The EMS 80 (control unit) If the amount of stored electricity in the second load following battery 52 (second downstream battery) is less than a predetermined amount of stored electricity, the charge and discharge conditions of the multiple interchangeable batteries 50 (interchangeable batteries 53 to 5N, first downstream battery) are changed so that the amount of stored electricity in the second load following battery 52 (second downstream battery) is more likely to increase (see step S212).

[0138] This configuration prevents the second load-following battery 52 from being able to discharge, reducing the remaining charge of the pseudo-system battery 51, and preventing the pseudo-system battery 51 from being able to fulfill its role as a pseudo-system power source K.

[0139] In addition, in the power supply system 1, The EMS 80 (control unit) If the amount of stored electricity in the second load following battery 52 (second downstream battery) is equal to or greater than a predetermined amount of stored electricity, the charge and discharge conditions of the multiple interchangeable batteries 50 (interchangeable batteries 53 to 5N, first downstream battery) are changed so that the amount of stored electricity in the second load following battery 52 (second downstream battery) is more likely to decrease (see step S214).

[0140] With this configuration, it is possible to prevent the second load following battery 52 from being unable to absorb surplus power and causing reverse power flow to the system power supply K (pseudo system battery 51) side.

[0141] In addition, in the power supply system 1, When the load following battery 51 (upstream battery) is unable to output power through the independent operation, Among the plurality of interchangeable batteries 50 (interchangeable batteries 52 to 5N, downstream batteries), The second load-following battery 52 (second downstream battery) The power generating unit is configured to output discharge power by the stand-alone operation, The EMS 80 (control unit) As shown in Figure 10, among the multiple interchangeable storage batteries 50 (interchangeable storage batteries 53 to 5N, first downstream storage battery), the interchangeable storage battery 50 located upstream (interchangeable storage battery 53, first downstream storage battery) is switched from the first mode to the second mode.

[0142] With this configuration, even if the load following storage battery 51 (upstream storage battery) is unable to output power through the independent operation, the storage battery 50 can be controlled to suitably accommodate power.

[0143] The solar power generation unit 40 according to this embodiment is one embodiment of a power generation unit. The EMS 80 according to this embodiment is one embodiment of a control unit. The storage battery 51 according to this embodiment (the load following storage battery 51 and the pseudo grid storage battery 51) is an embodiment of an upstream storage battery. Moreover, the storage batteries 52 to 5N according to this embodiment are an embodiment of downstream storage batteries. Moreover, the storage batteries 53 to 5N according to this embodiment are an embodiment of the first downstream storage battery. The storage battery 52 according to this embodiment (second load following storage battery 52) is an embodiment of a second downstream storage battery.

[0144] Although the embodiment of the present invention has been described above, the present invention is not limited to the above configuration, and various modifications are possible within the scope of the invention described in the claims.

[0145] For example, in this embodiment, the power supply system 1 is applied to a residential block T (a collection of houses), but is not limited to this. That is, the objects to which the power supply system is applied include areas divided by roads, railways, rivers, etc., such as a block that is a section of a city, ward, town, village, or urban area. The objects to which the power supply system is applied also include offices, schools, hospitals, etc.

[0146] For example, in this embodiment, the electricity retailer purchases electricity in bulk from the electric power company and supplies (interchanges) it appropriately between multiple homes H, but the electricity retailer does not have to purchase electricity in bulk from the electric power company.

[0147] The EMS 80 may also be configured by, for example, a home server (not shown), a control unit of a storage battery, or a HEMS provided in a home (when the power supply system 1 is applied to a home).

[0148] Furthermore, the power generating unit uses sunlight as natural energy, but may also use hydraulic power, wind power, tidal power, or the like, or may not use natural energy.

[0149] Furthermore, in the present embodiment, when interchange control is performed, an example has been shown in which the second mode is set for the most upstream storage battery 50 (storage battery 51) installed in the residence H (first residence H1) in the residential block T, but the storage battery 50 to which the second mode is set is not limited to the one installed in the residence H. For example, the most upstream storage battery 50 may be installed in a shared facility such as a meeting hall in the residential block T.

[0150] Furthermore, in this embodiment, when interchange control is executed, the second mode is set to one storage battery 50, but the number of storage batteries 50 to be set to the second mode is not limited to one, and the second mode may be set to a plurality of storage batteries 50. In this case, an appropriate number of storage batteries 50 may be set to the second mode among the plurality of storage batteries 50, in order from the storage battery arranged upstream.

[0151] Furthermore, the initial values ​​of the discharge possibility threshold and the charge possibility threshold in this embodiment (values ​​used in the interchange control process during normal times) and the changed values ​​used in the processes of steps S212 and S214 are merely examples and are not limited to these. Furthermore, the discharge possibility threshold and the charge possibility threshold in the processes of steps S212 and S214 may be changed in stages, for example, according to the remaining amount of stored power of the second load following storage battery 52. ​​This makes it possible to differentiate between the stages when the remaining amount of stored power of the second load following storage battery 52 still has some margin and when it does not.

[0152] The power supply system 1 may also include, for example, a load 10, a grid interconnection line La, an independent output line Lb, a power sensor Sa, a power sensor Sb, etc. In the present embodiment, the group G1 and the first group G2a each have one storage battery 50, but a plurality of storage batteries 50 may also belong to each group. [Explanation of symbols]

[0153] 1. Power supply system 10 Load 30 Energy Storage System 40 Solar Power Generation Department 50 Storage battery 80 EMS K grid power supply

Claims

1. a plurality of storage batteries connected in series between a grid power supply and a load, capable of charging with power and discharging the charged power in both grid-connected operation under normal circumstances and stand-alone operation during a power outage, thereby supplying power to the load; a plurality of power generation units connected to the storage battery and distributing generated power between a system power supply and the load; a control unit capable of controlling charging and discharging of the plurality of storage batteries; A power supply system comprising: The plurality of storage batteries The system is configured to be able to switch between the grid-connected operation and the independent operation in accordance with the power from a system power source, and in the event of a power outage, a plurality of downstream storage batteries located downstream of an upstream storage battery among the plurality of storage batteries perform the grid-connected operation based on discharge power output by the independent operation of the upstream storage battery located upstream, The control unit In the event of a power outage, Among the plurality of downstream storage batteries, at least two or more first downstream storage batteries, setting a first mode in which charging and discharging are controlled based on an instruction from the control unit; controlling charging and discharging based on a result of comparing a total generated power obtained by adding up the amounts of power generated by the plurality of power generation units with the power consumed by the load; A second downstream storage battery among the plurality of downstream storage batteries, which is located upstream of the plurality of first downstream storage batteries, a second mode is set in which charging and discharging are controlled based on the power flowing between the grid power supply and the load; Power supply system.

2. The total generated power excludes the amount of power generated by the power generation unit corresponding to the upstream storage battery. The power supply system according to claim 1 .

3. The control unit The charge / discharge conditions of the plurality of first downstream storage batteries can be changed based on the amount of electricity stored in the second downstream storage battery. The power supply system according to claim 1 .

4. The control unit when the amount of stored power in the second downstream storage battery is less than a predetermined amount of stored power, changing charge / discharge conditions of the plurality of first downstream storage batteries so that the amount of stored power in the second downstream storage battery is likely to increase; The power supply system according to claim 3 .

5. The control unit When the amount of stored power in the second downstream storage battery is equal to or greater than a predetermined amount of stored power, the charge / discharge conditions of the first downstream storage batteries are changed so that the amount of stored power in the second downstream storage battery is likely to decrease. The power supply system according to claim 3 .

6. When the output of the upstream storage battery by the independent operation becomes impossible, Among the plurality of downstream storage batteries, The second downstream storage battery is The power generating unit is configured to output discharge power by the stand-alone operation, The control unit switching the first downstream storage battery located on the upstream side among the plurality of first downstream storage batteries from the first mode to the second mode; The power supply system according to claim 1 .

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