Power supply system, power storage system, installation method, and display device

Abstract

To provide a power supply system, a power storage system, an installation method, and a display device that can reduce power purchased from a power grid when a plurality of power storage systems are connected between a load and the power grid.SOLUTION: A power supply system includes a first power storage system connected at a first location to wiring for supplying power from a power grid to a load, and a second power storage system connected to the wiring at a second location between the first location and the power grid, and the first power storage system includes a first power storage battery and controls charging and discharging of the first power storage battery on the basis of the power flow on the wiring between the first location and the second location, and the second power storage system includes a second power storage battery and controls charging and discharging of the second storage battery on the basis of the power flow on the wiring at a predetermined location closer to the power grid than the second location.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a power supply system, a power storage system, an installation method, and a display device. [Background technology]

[0002] There is a known power supply system in which a photovoltaic power generation system and a power storage system are connected to wiring that supplies power from a power grid (hereinafter simply referred to as a grid) to a load (household electrical appliances). A hybrid power supply system that includes a storage battery and a photovoltaic power generation panel (hereinafter referred to as a PV (Photovoltaic) panel) is also known (see Patent Document 1 below).

[0003] After introducing a power supply system, storage batteries may be added to increase the storage capacity. In this case, the storage capacity can be increased by adding more power supply systems. Specifically, multiple power supply systems are connected in parallel between a load and a grid. Each power supply system supplies power to a corresponding load. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-110903 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned configuration has the following problems. That is, when the first power supply system and the second power supply system, each including a power storage system, are connected between a load and a grid, the first power supply system and the second power supply system cannot exchange power with each other. When the remaining battery level of the storage battery in any of the power supply systems reaches the upper discharge limit, the power supply system cannot supply power to the load. There is a problem that the amount of power purchased from the grid increases in order to supply power to the load.

[0006] Therefore, an object of the present disclosure is to provide a power supply system, a power storage system, an installation method, and a display device that can reduce the amount of power purchased from the power grid when multiple power storage systems are connected between a load and the power grid. [Means for solving the problem]

[0007] A power supply system according to one aspect of the present disclosure includes a first storage system connected at a first location to wiring for supplying power from a power system to a load, and a second storage system connected to the wiring at a second location between the first location and the power system, where the first storage system includes a first storage battery and controls charging and discharging of the first storage battery based on the power flow on the wiring between the first location and the second location, and the second storage system includes a second storage battery and controls charging and discharging of the second storage battery based on the power flow on the wiring at a predetermined location closer to the power system than the second location. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a power supply system, a power storage system, an installation method, and a display device that can reduce power purchased from the power grid when a plurality of power storage systems are connected between a load and the power grid. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing a configuration of a power supply system according to a first embodiment of the present disclosure. [Diagram 2]FIG. 2 is a block diagram showing a configuration of a power supply system according to a first modified example of the present disclosure. [Diagram 3] FIG. 3 is a block diagram showing a configuration of a power supply system according to a second modification of the present disclosure. [Figure 4] FIG. 4 is a block diagram showing a configuration of a power supply system according to the second embodiment of the present disclosure. [Diagram 5] FIG. 5 is a block diagram showing a configuration of a power supply system according to a third modification of the present disclosure. [Figure 6] FIG. 6 is a block diagram showing a configuration of a power supply system according to the third embodiment of the present disclosure. [Figure 7] FIG. 7 is a block diagram showing a configuration of a power supply system according to a fourth modification of the present disclosure. [Figure 8] FIG. 8 is a diagram showing an example of a screen displayed on a display device of the first power storage system. [Figure 9] FIG. 9 is a diagram showing an example of a screen displayed on a display device of the second power storage system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Description of the embodiments of the present disclosure] The contents of the embodiments of the present disclosure will be listed and described below. At least a part of the embodiments described below may be arbitrarily combined.

[0011] (1) A power supply system according to a first aspect of the present disclosure includes a first power storage system connected at a first position to a wiring for supplying power from a power grid to a load, and a second power storage system connected to the wiring at a second position between the first position and the power grid, the first power storage system including a first storage battery and controlling charging and discharging of the first storage battery based on a power flow on the wiring between the first position and the second position, and the second power storage system including a second storage battery and controlling charging and discharging of the second storage battery based on a power flow on the wiring at a predetermined position closer to the power grid than the second position, thereby making it possible to reduce power purchased from the power grid.

[0012] (2) In the above (1), the load may include a specific load and a general load, and during a power outage in the power grid, the first power storage system may supply power to the general load, and the second power storage system may supply power to the specific load. This makes it possible to supply power to the specific load and the general load during a power outage in the power grid.

[0013] (3) In the above (1) or (2), the power supply system may further include a solar power generation panel, and the second location may be between a location where the power generated by the solar power generation panel is supplied to the wiring and the power grid. This makes it possible to avoid a situation where the power generated by the solar power generation panel cannot be consumed by the home.

[0014] (4) In the above (3), a solar power generation panel may be connected to the first power storage system, and the first power storage system may supply power generated by the solar power generation panel to wiring at the first location. This makes it possible to avoid a situation where the power generated by the solar power generation panel cannot be self-consumed.

[0015] (5) In the above (3), the power supply system may further include a solar power generation system including a solar power generation panel and connected to the wiring at a third location, and the third location may be located on the opposite side of the first location from the second location. This makes it possible to avoid a situation where the power generated by the solar power generation system cannot be self-consumed.

[0016] (6) In the above (4), the power supply system may further include a photovoltaic power generation system connected to the wiring at a third location, and the third location may be located on the opposite side of the first location from the second location. This makes it possible to avoid a situation where the power generated by the photovoltaic power generation system cannot be self-consumed.

[0017] (7) In the above (2), the first power storage system may supply power to the general load and the second power storage system during a power outage in the power grid, and the second power storage system may supply the power supplied from the first power storage system to the specific load. This allows power from the first power storage system to be supplied to the specific load during a power outage in the power grid, and even if power supply from the first power storage system is no longer available, the discharged power from the second storage battery can be supplied to the specific load. Therefore, the power supply to important electrical equipment (specific load) can be maintained for a longer period of time during a power outage in the power grid.

[0018] (8) In the above (7), the first power supplied from the first power storage system and the second power supplied from the second power storage system may be input to a distribution board, and power generated by a generator may be further input to the distribution board, and at least one of the first power, the second power, and the generated power may be supplied to a specific load via the distribution board. This makes it possible to maintain power supply to important electrical equipment (specific load) for an even longer period of time during a power outage in the grid.

[0019] (9) In any one of the above (1) to (8), the power supply system may further include a sensor that measures the charging and discharging power of the second power storage system and a display unit that displays the buying and selling power of the first power storage system, and the display unit may switch the display of the buying and selling power based on the charging and discharging power measured by the sensor. This allows accurate buying and selling power to be displayed to the user.

[0020] (10) A second aspect of the present disclosure relates to an installation method for a power storage system that connects a first power storage system and a second power storage system to wiring for supplying power from a power grid to a load, the first power storage system being installed so as to be connected to the wiring at a first position on the wiring, and the second power storage system being installed so as to be connected to the wiring at a second position between the first position and the power grid, such that the first power storage system controls charging and discharging of a first storage battery in the first power storage system based on a power flow on the wiring between the first position and the second position, and the second power storage system controls charging and discharging of a second storage battery in the second power storage system based on a power flow on the wiring at a predetermined position closer to the power grid than the second position, thereby making it possible to reduce power purchased from the power grid.

[0021] (11) A display device according to a third aspect of the present disclosure is a display device that displays the bought and sold power of any one of the power supply systems (1) to (8) above, and switches the display of the bought and sold power in response to a correction of the power flow on the wiring between the first location and the second location based on the charging and discharging power of the second power storage system, thereby making it possible to display accurate bought and sold power to a user.

[0022] (12) A fourth aspect of the present disclosure provides an energy storage system that is connected at a first location to a wiring for supplying power from a power grid to a load, the energy storage system supplies power to the load together with another energy storage system that is connected to the wiring at a second location between the first location and the power grid, the energy storage system includes a storage battery, and controls charging and discharging of the storage battery based on a power flow on the wiring between the first location and the second location. This makes it possible to reduce power purchased from the power grid when the energy storage system and the other energy storage system are connected between the load and the power grid.

[0023] (13) A power storage system according to a fifth aspect of the present disclosure is a power storage system connected to a wiring for supplying power from a power grid to a load, the power storage system supplies power to the load together with another power storage system connected at a first position to the wiring for supplying power from the power grid to the load, the power storage system is connected to the wiring at a second position between the first position and the power grid, the power storage system includes a storage battery, and controls charging and discharging of the storage battery based on a power flow on the wiring at a predetermined position closer to the power grid than the second position. This makes it possible to reduce power purchased from the power grid when the power storage system and the other power storage system are connected between the load and the power grid.

[0024] [Details of the embodiment of the present disclosure] In the following embodiments, the same parts are denoted by the same reference numerals, and their names and functions are also the same, so detailed description thereof will not be repeated.

[0025] (First embodiment) (System Configuration) Referring to FIG. 1, a power supply system 100 according to the first embodiment of the present disclosure includes a first power storage system 102 and a second power storage system 104. The first power storage system 102 and the second power storage system 104 are connected to AC wiring 902 (i.e., electric wires installed at a place of use such as a home) for supplying power to a load, which is an electric device (such as a home appliance), via a system 900. The AC wiring 902 is, for example, a single-phase three-wire system, and supplies AC 200V and 100V. The AC wiring 902 connects between the system 900 and a distribution board 106, and the electric device is connected to the AC wiring branched off from the distribution board 106. The first power storage system 102 is connected to the AC wiring 902 at a connection point 116. The second power storage system 104 is connected to the AC wiring 902 at a connection point 124.

[0026] The first power storage system 102 includes a first PCS (Power Conditioning System) 110 and a first storage battery 112. The first storage battery 112 is a rechargeable storage battery such as a lithium ion secondary battery. The first storage battery 112 functions as a DC power source. The first storage battery 112 is connected to the first PCS 110. The first PCS 110 includes a bidirectional power conversion circuit (such as a DC / AC converter). The first PCS 110 uses the power conversion circuit to convert AC power supplied from the outside (for example, a connection point 116 of the AC wiring 902) into DC power to charge the first storage battery 112, and converts the discharged power (DC power) of the first storage battery 112 into AC power and supplies it from the connection point 116 to the AC wiring 902. The first PCS 110 manages the state of the first storage battery 112. The first PCS 110 has a function of calculating the current charge amount (ie, SOC: State Of Charge) of the first storage battery 112, a function of preventing the first storage battery 112 from being overcharged and overdischarged, and the like.

[0027] The first power storage system 102 is connected to a PV panel 114. The PV panel 114 has a plurality of solar battery cells connected in series arranged on a plane and sealed with tempered glass or the like. The PV panel 114 functions as a DC power source. The first power storage system 102 is a hybrid power storage system. That is, the first PCS 110 converts the power (DC power) generated by the PV panel 114 into AC power using a power conversion circuit and supplies the AC power from a connection point 116 to an AC wiring 902. The first PCS 110 also charges the first storage battery 112 with surplus power from the PV panel 114. That is, the first PCS 110 boosts the power generated by the PV panel 114 to a charging voltage of the first storage battery 112 and supplies the power to the first storage battery 112.

[0028] The second power storage system 104 includes a second PCS 120 and a second storage battery 122. The second storage battery 122 is a rechargeable storage battery such as a lithium ion secondary battery, and functions as a DC power source. The second storage battery 122 is connected to the second PCS 120. The second PCS 120 includes a bidirectional power conversion circuit (such as a DC / AC converter). The second PCS 120 uses the power conversion circuit to convert AC power supplied from the outside (for example, a connection point 124 of the AC wiring 902) into DC power to charge the second storage battery 122, and converts the discharged power (DC power) of the second storage battery 122 into AC power and supplies it from the connection point 124 to the AC wiring 902. The second PCS 120 manages the state of the second storage battery 122. The second PCS 120 has a function of calculating the current charge amount (i.e., SOC) of the second storage battery 122, a function of preventing overcharging and overdischarging of the second storage battery 122, and the like. In contrast to the first power storage system 102, which is a hybrid type, the second power storage system 104 is called a single-function power storage system.

[0029] Between the connection point 116 and the connection point 124 on the AC wiring 902, a CT (Current Transformer) 130 for measuring the power flow is disposed. Between the connection point 124 on the AC wiring 902 and the grid 900, a CT 132 for measuring the power flow at the power receiving point where the power supply system 100 is connected to the grid 900 is disposed. The CTs 130 and 132 are, for example, current sensors. The first PCS 110 in the first power storage system 102 includes a measurement unit (hereinafter, referred to as a voltage measurement unit) for the voltage v1 at the connection point 116. The first PCS 110 calculates the power p1 at the position of the CT 130 from the current measurement value i1 and the voltage v1 of the CT 130. The second PCS 120 in the second power storage system 104 includes a voltage measurement unit for the voltage v2 at the connection point 124, and calculates the power p2 at the position of the CT 132 from the current measurement value i2 and the voltage v2 of the CT 132.

[0030] Specifically, the CT130 includes two CTs. The two CTs are each connected to two different wires excluding the neutral wire of the single-phase three-wire system, and the current of each phase is measured individually by the two CTs. The first PCS110 calculates power from the measured current value and the voltage measured by the voltage measurement unit of the corresponding phase, and calculates the total phase power p1 by adding up the two calculated powers. Similarly, the CT132 includes two CTs, and the two CTs are each connected to two different wires excluding the neutral wire of the single-phase three-wire system, and the current of each phase is measured individually by the two CTs. The second PCS120 calculates power from the measured current value and the voltage measured by the voltage measurement unit of the corresponding phase, and calculates the total phase power p2 by adding up the two calculated powers. As described below, the first PCS 110 of the first storage system 102 controls the charging and discharging of the first storage battery 112 in accordance with the calculated all-phase power p1, and the second PCS 120 of the second storage system 104 controls the charging and discharging of the second storage battery 122 in accordance with the calculated all-phase power p2.

[0031] (operation) The following describes the operation of the first power storage system 102 and the second power storage system 104, i.e., the charge / discharge control of the first storage battery 112 by the first PCS 110, and the charge / discharge control of the second storage battery 122 by the second PCS 120. The first power storage system 102 and the second power storage system 104 can operate without being synchronously operated with each other or being externally controlled by another control device.

[0032] Each of the first power storage system 102 and the second power storage system 104 has a control function for maximizing self-consumption of photovoltaic power, which is called a green mode. In the green mode, the first power storage system 102 and the second power storage system 104 always perform control so that the power at the connection point 116 and the connection point 124, which are respectively connected to the AC wiring 902, is 0 W. As a result, in the power supply system 100, if there is surplus power (power generation - power consumption), the first storage battery 112 and the second storage battery 122 are charged, and if there is a power shortage (power consumption - power generation), the first storage battery 112 and the second storage battery 122 are discharged. Note that the target value does not have to be 0 W. For example, the target value may be offset to the normal flow side in order to prevent the energy derived from the storage battery from flowing backward. For example, a forward power flow of several tens of W to several hundreds of W may be set as the target value.

[0033] The power supply system 100 as a whole operates as follows. That is, most of the charging and discharging for the load following control in the green mode is performed by the downstream first power storage system 102, and the first PCS 110 charges and discharges the first storage battery 112. Therefore, the upstream second power storage system 104 hardly contributes to charging and discharging, and the second PCS 120 hardly charges or discharges the second storage battery 122. The second PCS 120 only needs to perform following control for the difference between the power calculated from the measurement value of the CT 132 and the target value, and charge and discharge the second storage battery 122.

[0034] For example, assume that the target value of the upstream second power storage system 104 is a forward flow of 100 W, and the target value of the downstream first power storage system 102 is a forward flow of 200 W. In this case, the second PCS 120 of the second power storage system 104 controls the second storage battery 122 to discharge 100 W. That is, the first PCS 110 of the first power storage system 102 controls the charging and discharging of the first storage battery 112 according to the power generated by the PV panel 114 so that the power calculated from the measurement value by the CT 130 becomes the target value of 200 W. As a result, the second PCS 120 of the second power storage system 104 detects that the power calculated from the measurement value by the CT 132 is greater than the target value of 100 W. Therefore, the second PCS 120 controls the second storage battery 122 to discharge 100 W to become the target value (100 W).

[0035] Also, for example, assume that the target value of the upstream second power storage system 104 is a forward flow of 200 W, and the target value of the downstream first power storage system 102 is a forward flow of 100 W. In this case, the second PCS 120 of the second power storage system 104 controls the second storage battery 122 to be charged at 100 W. That is, the first PCS 110 of the first power storage system 102 controls the charging and discharging of the first storage battery 112 according to the power generated by the PV panel 114 so that the power calculated from the measurement value by the CT 130 becomes the target value of 100 W. As a result, the second PCS 120 of the second power storage system 104 detects that the power calculated from the measurement value by the CT 132 is smaller than the target value of 200 W. Therefore, the second PCS 120 controls the second storage battery 122 to be charged at 100 W so as to become the target value (200 W).

[0036] The first power storage system 102 and the second power storage system 104 control their respective storage batteries so that the power calculated from the measured values ​​of CT130 and CT132, respectively, becomes the respective target values, without knowing the target values ​​of the other power storage system. These operations do not require special synchronization or external control, and are performed automatically. Note that even if the target values ​​of the first power storage system 102 and the second power storage system 104 match, they may be charged and discharged by the amount of the measurement error. Even if this is done, the operation is only an error in the entire power supply system 100 including the first power storage system 102 and the second power storage system 104, and does not affect the green mode.

[0037] For example, when the remaining battery level (i.e., SOC) of the first storage battery 112 of the downstream first storage system 102 reaches the upper limit, the first storage battery 112 cannot be charged. In this case, the surplus power of the PV panel 114 is supplied from the first storage system 102 to the upstream second storage system 104, and the second PCS 120 charges the second storage battery 122 with the surplus power of the PV panel 114. Also, for example, when the remaining battery level of the first storage battery 112 of the downstream first storage system 102 reaches the lower limit, the discharge of the first storage battery 112 stops. In this case, the shortage of power is supplied by the discharged power from the second storage battery 122 of the upstream second storage system 104. These operations also do not require special synchronization or external control, and are automatically executed.

[0038] As a result, for example, if the upstream second power storage system 104 has a rated capacity of 5 kWh and the downstream first power storage system 102 has a rated capacity of 10 kWh, the power supply system 100 as a whole can achieve a capacity of 15 kWh. Furthermore, the power supply system 100 can charge the first storage battery 112 and the second storage battery 122 with surplus power from the PV panel 114, and the power supply system 100 as a whole can achieve self-consumption of power generated by the PV panel 114. The power supply system 100 can avoid a state in which the power generated by the PV panel 114 cannot be self-consumed, and can reduce the amount of power purchased from the power grid.

[0039] (First Modification) In the above, the first power storage system 102 is of a hybrid type, but the present invention is not limited to this. In the first modification, a solar power generation system is provided in parallel with the power storage system. (System Configuration) 2, a power supply system 140 according to a first modification is obtained by replacing the first power storage system 102 with a first power storage system 142 in the power supply system 100 shown in FIG 1, and adding a solar power generation system 150. In FIG 2, elements with the same reference numerals as in FIG 1 have the same functions as in FIG 1. Therefore, redundant description will not be repeated, and the following description will mainly focus on the differences.

[0040] The first power storage system 142 is connected to the AC wiring 902 at a connection point 116. The first power storage system 142 includes a first PCS 144 and a first storage battery 112. The first power storage system 142 is a single-function power storage system similar to the second power storage system 104. That is, the first PCS 144 includes a bidirectional power conversion circuit (such as a DC / AC converter). The first PCS 144 uses the power conversion circuit to convert AC power supplied from the outside (for example, a connection point 116 of the AC wiring 902) into DC power to charge the first storage battery 112, and converts the discharge power (DC power) of the first storage battery 112 into AC power and supplies it from the connection point 116 to the AC wiring 902. The first PCS 144 has a function of managing the state of the first storage battery 112, calculating the current charge amount (ie, SOC) of the first storage battery 112, a function of preventing the first storage battery 112 from being overcharged and overdischarged, and the like.

[0041] The photovoltaic power generation system 150 is connected to the AC wiring 902 at a connection point 156. The photovoltaic power generation system 150 includes a third PCS 152 and a PV panel 154. The PV panel 154 is connected to the third PCS 152. The PV panel 154 is configured similarly to the PV panel 114 shown in FIG. 1. The third PCS 152 includes a power conversion circuit (such as a DC / AC converter), and this power conversion circuit converts the power (DC power) generated by the PV panel 154 into AC power and supplies it from the connection point 156 to the AC wiring 902.

[0042] (operation) In the power supply system 140, the first power storage system 142 and the second power storage system 104 operate in the same manner as the first power storage system 102 and the second power storage system 104 shown in Fig. 1. The first power storage system 142 and the second power storage system 104 can operate without being synchronously operated with each other or being externally controlled by another control device.

[0043] Each of the first power storage system 142 and the second power storage system 104 operates in the green mode. That is, the first power storage system 142 and the second power storage system 104 always perform control so that the power at the connection point 116 and the connection point 124, which are respectively connected to the AC wiring 902, is 0 W. As a result, in the power supply system 140, if there is surplus power in the power generated by the solar power generation system 150, the first storage battery 112 and the second storage battery 122 are charged, and if there is a power shortage, the first storage battery 112 and the second storage battery 122 are discharged.

[0044] The power supply system 140 as a whole operates as follows. That is, most of the charging and discharging for the load following control in the green mode is performed by the downstream first power storage system 142, and the upstream second power storage system 104 hardly contributes to the charging and discharging. The second PCS 120 performs the following control only for the difference between the power calculated from the measurement value of the CT 132 and the target value, and charges and discharges the second storage battery 122.

[0045] For example, assume that the target value of the upstream second power storage system 104 is a forward flow of 100 W, and the target value of the downstream first power storage system 142 is a forward flow of 200 W. In this case, the second PCS 120 of the second power storage system 104 controls the second storage battery 122 to discharge 100 W. That is, the first PCS 144 of the first power storage system 142 controls the charging and discharging of the first storage battery 112 according to the power generated by the PV panel 154 of the photovoltaic power generation system 150 so that the power calculated from the measurement value by the CT 130 becomes the target value of 200 W. As a result, the second PCS 120 of the second power storage system 104 detects that the power calculated from the measurement value by the CT 132 is greater than the target value of 100 W. Therefore, the second PCS 120 controls the second storage battery 122 to discharge 100 W to become the target value (100 W).

[0046] Also, for example, assume that the target value of the upstream second power storage system 104 is a forward flow of 200 W, and the target value of the downstream first power storage system 142 is a forward flow of 100 W. In this case, the second PCS 120 of the second power storage system 104 controls the second storage battery 122 to be charged with 100 W. That is, the first PCS 144 of the first power storage system 142 controls the charging and discharging of the first storage battery 112 according to the power generated by the PV panel 154 of the photovoltaic power generation system 150 so that the power calculated from the measurement value by the CT 130 becomes the target value of 100 W. As a result, the second PCS 120 of the second power storage system 104 detects that the power calculated from the measurement value by the CT 132 is smaller than the target value of 200 W. Therefore, the second PCS 120 controls the second storage battery 122 to be charged with 100 W so as to become the target value (200 W).

[0047] The first power storage system 142 and the second power storage system 104 control their respective storage batteries so that the power calculated from the measured values ​​of CT 130 and CT 132 becomes the respective target values, without knowing the target values ​​of the other power storage system. These operations do not require special synchronization or external control, and are performed automatically.

[0048] For example, when the remaining battery level (i.e., SOC) of the first storage battery 112 of the downstream first storage system 142 reaches the upper limit, the first storage battery 112 cannot be charged by the surplus power of the PV panel 154 of the photovoltaic power generation system 150. In this case, the surplus power of the PV panel 154 of the photovoltaic power generation system 150 is supplied to the upstream second storage system 104, and the second PCS 120 charges the second storage battery 122 by the surplus power of the PV panel 154. Also, for example, when the remaining battery level of the first storage battery 112 of the downstream first storage system 142 reaches the lower limit, the discharge of the first storage battery 112 is stopped. In this case, the power shortage is supplied by the discharged power from the second storage battery 122 of the upstream second storage system 104. These operations also do not require special synchronization or external control, and are automatically executed.

[0049] This allows the power supply system 140 to charge the first storage battery 112 and the second storage battery 122 with surplus power from the PV panel 154 of the solar power generation system 150. Therefore, the power supply system 140 as a whole can realize self-consumption of power generated by the PV panel 154 of the solar power generation system 150. The power supply system 140 can avoid a state in which the power generated by the PV panel 154 of the solar power generation system 150 cannot be self-consumed, and can reduce power purchased from the power grid.

[0050] (Second Modification) The above-mentioned configurations may be combined. In a second modification, a hybrid power storage system and a solar power generation system are provided in parallel. (System Configuration) 3, power supply system 160 according to the second modification is obtained by adding solar power generation system 150 shown in FIG. 2 to power supply system 100 shown in FIG. 1. Power supply system 160 according to the second modification is also obtained by replacing first power storage system 142 in power supply system 140 shown in FIG. 2 with first power storage system 102 shown in FIG. 1. In FIG. 3, elements with the same reference numerals as those in FIG. 1 and FIG. 2 have the same functions as those in FIG. 1 and FIG. 2. Therefore, overlapping description will not be repeated, and the following description will mainly focus on the differences.

[0051] (operation) In the power supply system 160, the first power storage system 102 and the second power storage system 104 operate in the same manner as the first power storage system 102 and the second power storage system 104 shown in FIG. 1. Each of the first power storage system 102 and the second power storage system 104 operates in a green mode. That is, the first power storage system 102 and the second power storage system 104 always perform control so that the power at the connection point 116 and the connection point 124, which are respectively connected to the AC wiring 902, is 0 W. As a result, in the power supply system 160, if there is surplus power in the power generated by the PV panel 114 and the PV panel 154 of the solar power generation system 150, the first storage battery 112 and the second storage battery 122 are charged, and if there is a power shortage, the first storage battery 112 and the second storage battery 122 are discharged.

[0052] The power supply system 160 operates in the same manner as the power supply system 100 and the power supply system 140. That is, most of the charging and discharging for the load following control in the green mode is performed by the downstream first power storage system 102, and the upstream second power storage system 104 hardly contributes to the charging and discharging. The second PCS 120 performs the following control only for the difference between the power calculated from the measurement value of the CT 132 and the target value, and charges and discharges the second storage battery 122.

[0053] For example, assume that the target value of the upstream second power storage system 104 is a forward flow of 100 W, and the target value of the downstream first power storage system 142 is a forward flow of 200 W. In this case, the second PCS 120 of the second power storage system 104 controls the second storage battery 122 to discharge 100 W. That is, the first PCS 110 of the first power storage system 102 controls the charging and discharging of the first storage battery 112 according to the power generated by the PV panel 114 and the PV panel 154 of the photovoltaic power generation system 150 so that the power calculated from the measurement value by the CT 130 becomes the target value of 200 W. As a result, the second PCS 120 of the second power storage system 104 detects that the power calculated from the measurement value by the CT 132 is greater than the target value of 100 W. Therefore, the second PCS 120 controls the second storage battery 122 to discharge 100 W so as to become the target value (100 W).

[0054] Also, for example, assume that the target value of the upstream second power storage system 104 is a forward flow of 200 W, and the target value of the downstream first power storage system 142 is a forward flow of 100 W. In this case, the second PCS 120 of the second power storage system 104 controls the second storage battery 122 to be charged with 100 W. That is, the first PCS 110 of the first power storage system 102 controls the charging and discharging of the first storage battery 112 according to the power generated by the PV panel 114 and the PV panel 154 of the photovoltaic power generation system 150 so that the power calculated from the measurement value by the CT 130 becomes the target value of 100 W. As a result, the second PCS 120 of the second power storage system 104 detects that the power calculated from the measurement value by the CT 132 is smaller than the target value of 200 W. Therefore, the second PCS 120 controls the second storage battery 122 to be charged with 100 W so as to become the target value (200 W).

[0055] The first power storage system 102 and the second power storage system 104 control their respective storage batteries so that the power calculated from the measured values ​​of CT 130 and CT 132 becomes the respective target values, without knowing the target values ​​of the other power storage system. These operations do not require special synchronization or external control, and are performed automatically.

[0056] For example, when the remaining battery level (i.e., SOC) of the first storage battery 112 of the downstream first storage system 102 reaches the upper limit, the first storage battery 112 cannot be charged by the surplus power of the PV panel 114 and the PV panel 154 of the photovoltaic power generation system 150. In this case, the surplus power of the PV panel 114 and the PV panel 154 of the photovoltaic power generation system 150 is supplied to the upstream second storage system 104, and the second PCS 120 charges the second storage battery 122 by the surplus power of the PV panel 114 and the PV panel 154. Also, for example, when the remaining battery level of the first storage battery 112 of the downstream first storage system 102 reaches the lower limit, the discharge of the first storage battery 112 is stopped. In this case, the shortage of power is supplied by the discharged power from the second storage battery 122 of the upstream second storage system 104. These operations also do not require special synchronization or external control, and are automatically executed.

[0057] This allows the power supply system 160 to charge the first storage battery 112 and the second storage battery 122 with surplus power from the PV panel 114 and the PV panel 154 of the solar power generation system 150. Therefore, the power supply system 160 as a whole can realize self-consumption of the power generated by the PV panel 114 and the PV panel 154 of the solar power generation system 150. The power supply system 160 can avoid a state in which the power generated by the PV panel 114 and the PV panel 154 of the solar power generation system 150 cannot be self-consumed, and can reduce the amount of power purchased from the power grid.

[0058] Second embodiment In the above, the power supply system supplies power to the load in a normal state when no power outage occurs in the grid 900, but is not limited to this. The power supply system according to the second embodiment supplies power to the load even when a power outage occurs in the grid 900.

[0059] (System Configuration) 4, a power supply system 200 according to a second embodiment of the present disclosure includes a first power storage system 202 and a second power storage system 204. In the power supply system 200, the first power storage system 102 and the second power storage system 104 in the power supply system 100 shown in FIG. 1 are replaced with the first power storage system 202 and the second power storage system 204, respectively, a changeover switch 206 is added, and a general load 208 and a specific load 218 not shown in FIG. 1 are clearly shown. In FIG. 4, elements with the same reference numerals as in FIG. 1 have the same functions as in FIG. 1. Therefore, the following mainly describes the differences without repeating the description.

[0060] The first power storage system 202 is connected to the AC wiring 902 at a connection point 116. The first power storage system 202 includes a first PCS 210 and a first storage battery 112. The first storage battery 112 is connected to the first PCS 210. The first PCS 210 includes a bidirectional power conversion circuit (such as a DC / AC converter). The first PCS 210 uses the power conversion circuit to convert AC power supplied from the outside (for example, a connection point 116 of the AC wiring 902) into DC power to charge the first storage battery 112, and converts the discharge power (DC power) of the first storage battery 112 into AC power and supplies it from the connection point 116 to the AC wiring 902. The first PCS 210 has a function of managing the state of the first storage battery 112, a function of calculating the current charge amount (i.e., SOC) of the first storage battery 112, a function of preventing overcharging and overdischarging of the first storage battery 112, and the like.

[0061] The first power storage system 202 is connected to the PV panel 114, and is a hybrid power storage system. That is, the first PCS 210 converts the power (DC power) generated by the PV panel 114 into AC power using a power conversion circuit, and supplies the AC power from the connection point 116 to the AC wiring 902. The first PCS 210 also charges the first storage battery 112 with surplus power from the PV panel 114.

[0062] The second power storage system 204 is connected to the AC wiring 902 at the connection point 124. The second power storage system 204 includes a second PCS 212 and a second storage battery 122. The second storage battery 122 is connected to the second PCS 212. The second PCS 212 includes a bidirectional power conversion circuit (such as a DC / AC converter). The second PCS 212 converts AC power supplied from the outside (for example, a connection point 124 of the AC wiring 902) into DC power using the power conversion circuit to charge the second storage battery 122, and converts the discharge power (DC power) of the second storage battery 122 into AC power and supplies it from the connection point 124 to the AC wiring 902. The second PCS 212 has a function of managing the state of the second storage battery 122, a function of calculating the current charge amount (i.e., SOC) of the second storage battery 122, a function of preventing overcharging and overdischarging of the second storage battery 122, and the like. The second power storage system 204 is a single-function power storage system.

[0063] The first power storage system 202 has an independent output terminal 222 that outputs power when the grid 900 fails. For example, the first PCS 210 of the first power storage system 202 outputs single-phase three-wire 200V and 100V from the independent output terminal 222. The independent output terminal 222 is connected to a changeover switch 206, which is connected to the distribution board 106. The second power storage system 204 has an independent output terminal 214 that outputs power when the grid 900 fails. In addition, the second power storage system 204 has an auxiliary input terminal 216, which is connected to the distribution board 106 by an electric wire 220. The auxiliary input terminal 216 is provided to draw in an independent output of a solar power generation PCS, for example.

[0064] The changeover switch 206, during normal operation of the system 900, supplies power from the AC wiring 902 to the distribution board 106. This supplies power to the general load 208 and the specific load 218. The power supplied to the second PCS 212 via the electric wire 220 is bypassed by the second PCS 212, and is output as is from the independent output terminal 214 and supplied to the specific load 218.

[0065] When a power outage occurs in the grid 900, the changeover switch 206 cuts off the connection with the AC wiring 902, and supplies power supplied from the independent output terminal 222 of the first power storage system 202 to the distribution board 106. This causes power to be supplied from the first power storage system 202 to the general load 208. Power from the first power storage system 202 is supplied to the specific load 218 via the electric wire 220 and the second power storage system 204. That is, the first power storage system 202 can supply power to all loads in the home, including the 200V load, even during a power outage in the grid 900.

[0066] (operation) (normal time) The power supply system 200 operates in the green mode during normal operation of the grid 900, similar to the power supply system 100 shown in Fig. 1. That is, the first PCS 210 of the first power storage system 202 controls the charging and discharging of the first storage battery 112 according to the power generated by the PV panel 114, similar to the first PCS 110 of the first power storage system 102, so that the power calculated from the measurement value by the CT 130 becomes the target value. The second power storage system 204 controls the charging and discharging of the second storage battery 122, similar to the second PCS 120 of the second power storage system 104, so that the power calculated from the measurement value by the CT 132 becomes the target value of the second power storage system 204. The charging and discharging power of the second storage battery 122 is a value corresponding to the difference between the target value of the first power storage system 202 and the target value of the second power storage system 204.

[0067] Therefore, during normal operation of the grid 900, the power supply system 200 can charge the first storage battery 112 and the second storage battery 122 with surplus power from the PV panel 114, and the power supply system 200 as a whole can achieve self-consumption of the power generated by the PV panel 114. The power supply system 200 can avoid a state in which the power generated by the PV panel 114 cannot be self-consumed, and can reduce the amount of power purchased from the power grid.

[0068] (During a power outage) When a power outage occurs in the grid 900, as described above, the changeover switch 206 cuts off the connection with the AC wiring 902 and supplies the power supplied from the independent output terminal 222 of the first power storage system 202 to the distribution board 106. When a power outage occurs in the grid 900, the first power storage system 202 stops supplying power to the AC wiring 902 and supplies the power generated by the PV panel 114 from the independent output terminal 222. If the power generated by the PV panel 114 is insufficient, the first power storage system 202 discharges the first storage battery 112 and supplies it from the independent output terminal 222. This causes the power from the first power storage system 202 to be supplied to the general load 208. The distribution board 106 is also connected to the second power storage system 204, and the power from the first power storage system 202 is supplied to the specific load 218 via the electric wire 220, the auxiliary input terminal 216, the second PCS 212, and the independent output terminal 214.

[0069] If the power generated by the PV panel 114 is large, there is surplus power, and the first storage battery 112 is in a fully charged state, the second PCS 212 charges the second storage battery 122 with the surplus power of the PV panel 114 supplied via the electric wire 220 and the second PCS 212. In the first storage system 202, when the power generated by the PV panel 114 is insufficient at night or in rainy weather, and the remaining battery level (i.e., SOC) of the first storage battery 112 reaches a lower limit, it becomes impossible to supply power from the first storage system 202. In that case, the second PCS 212 of the second storage system 204 discharges the second storage battery 122 and supplies power to the specific load 218 from the independent output terminal 214.

[0070] Therefore, the power supply system 200 can supply power from the first power storage system 202 to the specific load 218 during a power outage in the grid 900, and can supply discharged power from the second storage battery 122 of the second power storage system 204 to the specific load 218 even if power supply from the first power storage system 202 is stopped. Therefore, power supply to important electric equipment (specific load 218) can be maintained for a longer period of time during a power outage in the grid 900.

[0071] (Third Modification) The power supply system may be provided with a configuration for more reliably supplying power to a specific load. (System Configuration) With reference to Fig. 5, a power supply system 240 according to the third modification includes a first power storage system 202, a second power storage system 204, a distribution board 242, and a generator 244. The power supply system 240 is obtained by adding a distribution board 242 and a generator 244 to the power supply system 200 shown in Fig. 4. In Fig. 5, elements denoted with the same reference numerals as in Fig. 4 have the same functions as in Fig. 4. Therefore, redundant description will not be repeated, and the following description will mainly focus on the differences.

[0072] The generator 244 is, for example, an EV (Electric Vehicle), an HEV (Hybrid Electric Vehicle), or a generator using a gas cylinder such as a portable stove. The EV or HEV is equipped with a power conversion system that supplies power to home electrical appliances using an on-board storage battery, and is known as V2H (Vehicle to Home). The distribution board 242 is connected to the independent output terminal 214 and the generator 244, and is also connected to the distribution board 106 via an electric wire 246. The distribution board 242 supplies one of the three input power systems to the specific load 218.

[0073] (operation) (normal time) The power supply system 240 operates in the green mode during normal operation of the grid 900, similarly to the power supply system 100 shown in Fig. 1 and the power supply system 200 shown in Fig. 4. That is, the first PCS 210 of the first power storage system 202 controls the charging and discharging of the first storage battery 112 according to the power generated by the PV panel 114 so that the power calculated from the measurement value by the CT 130 becomes the target value. The second power storage system 204 controls the charging and discharging of the second storage battery 122 so that the power calculated from the measurement value by the CT 132 becomes the target value of the second power storage system 204. The charging and discharging power of the second storage battery 122 is a value according to the difference between the target value of the first power storage system 202 and the target value of the second power storage system 204.

[0074] The power supplied from the AC wiring 902 is supplied to the general load 208 via the changeover switch 206 and the distribution board 106. The power supplied from the AC wiring 902 is also supplied to the distribution board 242 via the changeover switch 206, the distribution board 106, and an electric wire 246. The distribution board 242 supplies the power supplied via the electric wire 246 to the specific load 218.

[0075] Therefore, during normal operation of the grid 900, the power supply system 240 can charge the first storage battery 112 and the second storage battery 122 with surplus power from the PV panel 114, and the power supply system 240 as a whole can achieve self-consumption of the power generated by the PV panel 114. The power supply system 240 can avoid a state in which the power generated by the PV panel 114 cannot be self-consumed, and can reduce the amount of power purchased from the power grid.

[0076] (During a power outage) When a power outage occurs in the system 900, the system operates in the same manner as the power supply system 200 shown in FIG. 4. The changeover switch 206 cuts off the connection with the AC wiring 902, and supplies the power supplied from the independent output terminal 222 of the first power storage system 202 to the distribution board 106. When a power outage occurs in the system 900, the first power storage system 202 stops supplying power to the AC wiring 902, and supplies the power generated by the PV panel 114 from the independent output terminal 222. If the power generated by the PV panel 114 is insufficient, the second PCS 212 discharges the first storage battery 112 and supplies it from the independent output terminal 222. This causes the power from the first power storage system 202 to be supplied to the general load 208. The power from the first power storage system 202 is supplied to the specific load 218 via the changeover switch 206, the distribution board 106, the electric wire 246, and the distribution board 242.

[0077] If the power generated by the PV panel 114 is large, there is surplus power, and the first storage battery 112 is in a fully charged state, the second PCS 212 charges the second storage battery 122 with the surplus power of the PV panel 114 supplied via the electric wire 220 and the second PCS 212. In the first storage system 202, when the power generated by the PV panel 114 is insufficient at night or in rainy weather, and the remaining battery level (i.e., SOC) of the first storage battery 112 reaches a lower limit, the first storage system 202 cannot supply power. In that case, the second PCS 212 of the second storage system 204 discharges the second storage battery 122 and outputs power from the independent output terminal 214. The distribution board 242 supplies the power supplied from the independent output terminal 214 to the specific load 218. Furthermore, when the remaining battery charge (i.e., SOC) of the second storage battery 122 reaches a lower limit, the second power storage system 204 cannot output power from the independent output terminal 214. In that case, the distribution board 242 supplies the power generated by the generator 244 to the specific load 218.

[0078] Therefore, the power supply system 240 can supply power from the first power storage system 202 to the specific load 218 during a power outage in the grid 900, and can supply discharged power from the second storage battery 122 of the second power storage system 204 to the specific load 218 even if power supply from the first power storage system 202 is no longer possible. Furthermore, if the second power storage system 204 is no longer able to supply discharged power from the second storage battery 122, the power supply system 240 can supply generated power from the generator 244 to the specific load 218. Therefore, power supply to important electrical equipment (specific load 218) can be maintained for an even longer period of time during a power outage in the grid 900.

[0079] Third embodiment In a power storage system, the operating status (charging and discharging power of the storage battery, power bought and sold, power consumption, etc.) is displayed on an information terminal such as a remote control. This allows a user of a home in which a power storage system is installed to check the operating status of the power storage system, including the power bought and sold and power consumption that are directly related to the power bill. However, in the power supply system shown in Figures 1 to 5, when the operating status of each power storage system is displayed, some of the displayed information is not accurate.

[0080] For example, in the power supply system 100 shown in Fig. 1, the charging / discharging power, buying / selling power, and power consumption of the first storage battery 112, and the power generated by the PV panel 114 are displayed as the operating state of the first storage system 102. The charging / discharging power, buying / selling power, and power consumption of the second storage battery 122 are displayed as the operating state of the second storage system 104. In this case, the discharging power (negative is assumed to be charging power) of each storage battery is measured by each PCS, the selling power (negative is assumed to be purchasing power) is measured by each CT, and the power generated by the PV panel 114 is measured by the first PCS 110. The power consumption is calculated as power consumption = reverse conversion power - buying / selling power. The reverse conversion power is the AC output of each PCS, and is measured by each PCS.

[0081] As for the first power storage system 102, the charge / discharge power and power consumption of the first storage battery 112 and the power generation of the PV panel 114 are correct, but the power bought and sold deviates by the charge / discharge power of the second power storage system 104. As for the second power storage system 104, the charge / discharge power and power bought and sold of the second storage battery 122 are correct, but the power consumption deviates by the power associated with the reverse conversion and forward conversion by the inverter included in the first PCS 110 of the first power storage system 102. Therefore, when the operating states of the first power storage system 102 and the second power storage system 104 are displayed on the respective remote controls, some information becomes inaccurate. The same is true for the power supply systems shown in FIG. 2 to FIG. 5. The power supply system according to the third embodiment of the present disclosure is intended to solve this problem.

[0082] (System Configuration) 6, a power supply system 300 according to a third embodiment of the present disclosure includes a first power storage system 302, a second power storage system 304, a first display device 306, a second display device 308, and a CT 310. The power supply system 300 is obtained by replacing the first power storage system 102 and the second power storage system 104 with the first power storage system 302 and the second power storage system 304, respectively, in the power supply system 100 shown in FIG. 1, and adding the first display device 306, the second display device 308, and the CT 310. In FIG. 6, elements with the same reference numerals as those in FIG. 1 have the same functions as those in FIG. 1. Therefore, the following mainly describes the differences without repeating the description.

[0083] The first power storage system 302 is connected to the AC wiring 902 at a connection point 116. The first power storage system 302 includes a first PCS 312 and a first storage battery 112. The first storage battery 112 is connected to the first PCS 312. The first PCS 312 includes a bidirectional power conversion circuit (such as a DC / AC converter). The first PCS 312 converts AC power supplied from the outside (for example, a connection point 116 of the AC wiring 902) into DC power using the power conversion circuit to charge the first storage battery 112, and converts the discharge power (DC power) of the first storage battery 112 into AC power and supplies it from the connection point 116 to the AC wiring 902. The first PCS 312 has a function of managing the state of the first storage battery 112, a function of calculating the current charge amount (i.e., SOC) of the first storage battery 112, a function of preventing overcharging and overdischarging of the first storage battery 112, and the like. The first PCS 312 includes a calculation unit 316. The calculation unit 316 includes, for example, an arithmetic device such as a CPU (Central Processing Unit). The calculation unit 316 calculates the purchased and sold power of the power supply system 300, as described below.

[0084] The first power storage system 302 is connected to the PV panel 114, and is a hybrid power storage system. That is, the first PCS 312 converts the power (DC power) generated by the PV panel 114 into AC power using a power conversion circuit, and supplies the AC power from the connection point 116 to the AC wiring 902. The first PCS 312 also charges the first storage battery 112 with surplus power from the PV panel 114.

[0085] The second power storage system 304 is connected to the AC wiring 902 at the connection point 124. The second power storage system 304 includes a second PCS 314 and a second storage battery 122. The second storage battery 122 is connected to the second PCS 314. The second PCS 314 includes a bidirectional power conversion circuit (such as a DC / AC converter). The second PCS 314 converts AC power supplied from the outside (for example, the connection point 124 of the AC wiring 902) into DC power using the power conversion circuit to charge the second storage battery 122, and converts the discharge power (DC power) of the second storage battery 122 into AC power and supplies it from the connection point 124 to the AC wiring 902. The second PCS 314 has a function of managing the state of the second storage battery 122, a function of calculating the current charge amount (i.e., SOC) of the second storage battery 122, a function of preventing overcharging and overdischarging of the second storage battery 122, and the like. The second power storage system 304 is a single-function power storage system.

[0086] The first display device 306 and the second display device 308 are display devices such as liquid crystal panels, and display information on the operation states of the first power storage system 302 and the second power storage system 304, respectively. The first display device 306 and the second display device 308 are connected to the first PCS 312 and the second PCS 314, respectively. The first display device 306 receives and displays the charging / discharging power, the buying / selling power, and the power consumption of the first storage battery 112, and the power generated by the PV panel 114, as the operation state of the first power storage system 302, from the first PCS 312. The second display device 308 receives and displays the charging / discharging power, the buying / selling power, and the power consumption of the second storage battery 122, as the operation state of the second power storage system 304, from the second PCS 314.

[0087] The CT310 is, for example, a current sensor. The CT310 is connected to the first PCS312, and a measurement value of the CT310 is input to the first PCS312 (specifically, the calculation unit 316). The CT310 is arranged in a wiring (single-phase three-wire) that connects the second power storage system 304 to the AC wiring 902. Specifically, the CT310 is arranged in one of two wires excluding the neutral wire of the single-phase three-wire. The second power storage system 304 is connected in a single-phase three-wire manner, but has a single-phase two-wire output, and therefore, if the CT310 is arranged in only one wire, the output power of the second PCS314 can be correctly measured.

[0088] The calculation unit 316 of the first PCS 312 calculates the buying and selling power of the power supply system 300 by correcting the reverse flow power measured by the CT 130 as a single system with the output power of the second power storage system 304 measured by the CT 310. For example, when reverse flow, charging power, and selling power are expressed by positive values ​​and forward flow, discharging power, and purchasing power are expressed by negative values, the calculation unit 316 calculates the buying and selling power by subtracting the output power of the second power storage system 304 from the reverse flow power measured by the CT 130. That is, the buying and selling power calculated by the calculation unit 316 does not include a deviation due to the charging and discharging power of the second power storage system 304. Therefore, the first display device 306 can display the accurate buying and selling power of the power supply system 300.

[0089] The first PCS 312 of the first power storage system 302 can correctly measure the charge / discharge power and power consumption of the first storage battery 112, and the power generated by the PV panel 114. Therefore, the calculation unit 316 of the first PCS 312 can correctly calculate the power bought and sold of the power supply system 300, and the charge / discharge power, power bought and sold, power consumption of the first storage battery 112, and the power generated by the PV panel 114 can all be displayed as correct values ​​on the first display device 306. That is, the first display device 306 can switch the display of the power bought and sold in response to the correction of the power flow on the wiring 902 between the connection point 116 and the connection point 124 based on the charge / discharge power of the second power storage system 304. This allows the user to check the information on the operating state of the power supply system 300 with correct values ​​by looking at the first display device 306.

[0090] 2 to 5, a CT can be similarly arranged in the wiring (single-phase three-wire) connecting the second power storage system to the AC wiring 902, and the measurement value of the CT can be input to the PCS of the first power storage system. This allows information on the operating state of the power supply system to be correctly displayed on the display device of the first power storage system.

[0091] (Fourth Modification) In the above, a case has been described in which the CT310 is connected to the first PCS312 of the first power storage system 302, and the calculation unit 316 of the first PCS312 corrects the power flow calculated from the measurement value of the CT130 based on the power flow calculated from the measurement value of the CT310. However, this is not limiting. The CT310 may be connected to the first display device.

[0092] 7, a power supply system 330 according to a fourth modification includes a first power storage system 332, a second power storage system 304, a first display device 334, a second display device 308, and a CT 310. The power supply system 330 is obtained by replacing the first power storage system 302 and the first display device 306 in the power supply system 300 shown in FIG. 6 with the first power storage system 332 and the first display device 334, respectively. In FIG. 7, elements having the same reference numerals as those in FIG. 6 have the same functions as those in FIG. 6. Therefore, the following mainly describes the differences without repeating the description.

[0093] The first power storage system 332 includes a first PCS 336 and a first storage battery 112. The first PCS 336 is different from the first PCS 312 shown in FIG. 6 in that it is not connected to the CT 310 and does not include a calculation unit. The first PCS 336 is otherwise the same as the first PCS 312 shown in FIG. 6. The first display device 334 is a display device such as a liquid crystal panel, and displays information about the operating state of the first power storage system 332. The first display device 334 is connected to the first PCS 312 and the CT 310. The first display device 334 includes a calculation unit (e.g., a calculation device such as a CPU) 338 that calculates a power flow from a measurement value of the CT 310. The calculation unit 338 receives the power flow calculated by the first PCS 336 from the measurement value of the CT 130 from the first PCS 336, and calculates the bought and sold power of the power supply system 330 in the same manner as the calculation unit 316 shown in FIG. 6. That is, the calculation unit 338 calculates the bought and sold power of the power supply system 330 by correcting the reverse flow power (received from the first PCS 336) measured by the CT 130 as a single system with the output power of the second power storage system 304 measured by the CT 310. That is, the bought and sold power calculated by the calculation unit 338 does not include a deviation due to the charging and discharging power of the second power storage system 304. Therefore, the first display device 338 can display the accurate bought and sold power of the power supply system 330.

[0094] In the power supply system 300 shown in FIG. 6, when the CT 310 is not provided, each of the first display device 306 and the second display device 308 may be provided with a function (for example, an operation unit) for disabling the display of information. For example, by disabling the display of the bought and sold power in the first display device 306, the screen 400 shown in FIG. 8 is displayed on the first display device 306. In the screen 400, "*" represents the numbers 0 to 9, and "-" represents that the display is disabled and the numbers are not displayed. In the screen 400, the bought and sold power that is not a correct value is not displayed. For example, by disabling the display of the power consumption in the second display device 308, the screen 402 shown in FIG. 9 is displayed on the second display device 308. In the screen 402, the power consumption that is not a correct value is not displayed. This allows the user to check the bought and sold power and the power consumption that he or she is interested in by looking at the second display device 308 and the first display device 306, respectively.

[0095] Although the present disclosure has been described above by explaining the embodiments, the above-mentioned embodiments are merely examples, and the present disclosure is not limited to only the above-mentioned embodiments. The scope of the present disclosure is indicated by each claim in the claims, taking into consideration the description of the detailed description of the invention, and includes all modifications within the meaning and scope equivalent to the wording described therein. [Explanation of symbols]

[0096] 100, 140, 160, 200, 240, 300, 330 Power Supply System 102, 142, 202, 302, 332 First storage system 104, 204, 304 Second storage system 106, 242 Distribution board 110, 144, 210, 312, 336 1st PCS 112 First Battery 114, 154 PV panels 116, 124, 156 connection points 120, 212, 314 2nd PCS 122 Second Battery 130, 132, 310 CT 150 Solar power generation system 152 3rd PCS 206 Changeover Switch 208 General load 214, 222 Independent output terminal 216 Auxiliary input terminal 218 Specific load 220, 246 electric wire 244 Generator 306, 334 1st display device 308 2nd display device 316, 338 Calculation section 400, 402 screens 900 lines 902 AC wiring

Claims

1. a first power storage system connected at a first position to a wiring for supplying power from a power grid to a load; a second storage system connected to the wiring at a second location between the first location and the power grid; the first power storage system includes a first storage battery, and controls charging and discharging of the first storage battery based on a power flow on the wiring between the first location and the second location; The second power storage system includes a second storage battery, and the power supply system controls charging and discharging of the second storage battery based on a power flow on the wiring at a predetermined position closer to the power grid than the second position.

2. The load includes a specific load and a general load, In the event of a power outage in the power grid, The first power storage system supplies power to the general load; The power supply system according to claim 1 , wherein the second power storage system supplies power to the specific load.

3. Further comprising a photovoltaic panel; 3 . The power supply system according to claim 1 , wherein the second position is between the power grid and a position where power generated by the solar power generation panel is supplied to the wiring. 4 .

4. The solar power generation panel is connected to the first power storage system, The power supply system according to claim 3 , wherein the first power storage system supplies the power generated by the solar power generation panel to the wiring at the first location.

5. a solar power generation system including the solar power panel and connected to the wiring at a third location; The power supply system according to claim 3 , wherein the third position is located on an opposite side of the first position from the second position.

6. a solar power generation system connected to the wiring at a third location; The power supply system according to claim 4 , wherein the third position is located on an opposite side of the first position from the second position.

7. The first power storage system supplies power to the general load and the second power storage system during a power outage in the power grid; The power supply system according to claim 2 , wherein the second power storage system supplies the power supplied from the first power storage system to the specific load.

8. The first power supplied from the first power storage system and the second power supplied from the second power storage system are input to a distribution board; The distribution board further receives the power generated by the generator, The power supply system according to claim 7 , wherein at least one of the first power, the second power, and the generated power is supplied to the specific load via the distribution board.

9. A sensor for measuring charge / discharge power of the second power storage system; A display unit that displays the purchased and sold power of the first power storage system, The power supply system according to claim 1 , wherein the display unit switches a display of the bought and sold power based on the charged and discharged power measured by the sensor.

10. A method for installing a power storage system, comprising the steps of: connecting a first power storage system and a second power storage system to wiring for supplying power from a power grid to a load, the method comprising the steps of: the first power storage system is installed so as to be connected to the wiring at a first position on the wiring; the second power storage system is installed so as to be connected to the wiring at a second location between the first location and the power grid; This means: the first power storage system controls charging and discharging of a first storage battery in the first power storage system based on a power flow on the wiring between the first location and the second location; The second power storage system controls charging and discharging of a second storage battery in the second power storage system based on a power flow on the wiring at a predetermined position closer to the power grid than the second position.

11. A display device for displaying bought and sold power in the power supply system according to claim 1 or 2, a display device that switches a display of the bought and sold power in response to a correction of a power flow on the wiring between the first location and the second location based on the charging and discharging power of the second storage system.

12. A power storage system connected at a first position to a wiring for supplying power from a power grid to a load, The storage system supplies power to a load together with another storage system connected to the wiring at a second location between the first location and the power grid; The power storage system includes a storage battery, and controls charging and discharging of the storage battery based on a power flow on the wiring between the first location and the second location.

13. A power storage system connected to a wiring for supplying power from a power grid to a load, The power storage system supplies power to a load together with another power storage system connected at a first position to a wiring for supplying power from the power grid to the load; the energy storage system is connected to the wiring at a second location between the first location and the power grid; The power storage system includes a storage battery, and controls charging and discharging of the storage battery based on a power flow on the wiring at a predetermined position closer to the power grid than the second position.

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