Power supply system

Abstract

This provides a power supply system that allows adjustment of the timing at which the maintenance mode of the energy storage device ends. [Solution] In a power supply system, the energy storage device 14 is configured to operate in a maintenance mode in which, when predetermined maintenance start conditions are met, it performs a charging process to charge the remaining energy until it reaches an upper limit, and a discharge process to discharge the energy to the power line 2 so that the power at the power receiving point of the facility 3 becomes the target power receiving point power. The energy storage device 14 transmits discharge start information indicating that it has started or is scheduled to start the discharge process, and maintenance end information indicating that it has finished operating in maintenance mode to the power generator 9 or communication device 7. The power generator 9 adjusts the generated power supplied to the power line 2 according to the discharge start information and maintenance end information received from the energy storage device 14 or communication device 7.

Description

Technical Field

[0001] The present invention relates to a power supply system provided in a facility, in which a power generation device, a power storage device, and a power load are connected to a power line connected to a power system.

Background Art

[0002] Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2016-73073) describes a power supply system provided with a power generation device and a power storage device. When a power generation device and a power storage device are provided, there is an advantage that power can be supplied from the power generation device and the power storage device to the power load even if a power outage occurs in the power system. Further, even if one of the power generation device and the power storage device stops operating while a power outage is occurring in the power system, if the other is operating, the supply of power to the power load can be continued. Furthermore, since the power storage device can freely charge and discharge, there is an advantage that the power storage device can be used to increase or decrease the received power at the facility's power receiving point.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The power storage device may operate in a maintenance mode in which it charges until the remaining charge amount (charge rate (SOC: State Of Charge)) reaches the upper limit value, and then discharges until the remaining charge amount reaches the lower limit value. Therefore, while the power storage device is operating in the maintenance mode, it becomes impossible to freely charge and discharge the power storage device, and as a result, the power storage device cannot be used to increase or decrease the received power at the facility's power receiving point.

[0005] Furthermore, in a power supply system configured as shown in Figure 1, if the energy storage device is configured to adjust its charging and discharging power so that, for example, the power at the point of reception becomes zero, then reducing the power generated by the generator will increase the discharge power of the energy storage device, thereby accelerating the decrease in the remaining energy storage capacity. In other words, by reducing the power generated by the generator while the energy storage device is operating in maintenance mode, the time required for the remaining energy storage capacity to decrease from the upper limit to the lower limit (i.e., the period during which the energy storage device is operating in maintenance mode) can be shortened. This means that the timing of the end of the energy storage device's maintenance mode may be adjustable by the operation of the generator.

[0006] However, conventional power supply systems are not configured to transmit information from the energy storage device to the power generation device when the energy storage device is operating in maintenance mode. Therefore, even if the energy storage device is operating in maintenance mode, the power generation device cannot know this, and the power generation device cannot reduce the power output while the energy storage device is in maintenance mode as described above.

[0007] The present invention has been made in view of the above-mentioned problems, and its objective is to provide a power supply system that can adjust the timing at which the maintenance mode of a power storage device ends. [Means for solving the problem]

[0008] A characteristic configuration of the power supply system according to the present invention for achieving the above objective is a power supply system in which a power generation device, a power storage device, and a power load are connected to a power line installed in a facility and connected to a power grid, The power generation device and the energy storage device are capable of communicating information with each other directly or indirectly via a communication device. The energy storage device is configured to operate in a maintenance mode in which, when predetermined maintenance start conditions are met, it performs a charging process in which it charges from the power line without discharging until the remaining energy storage reaches the upper limit, and after the remaining energy storage reaches the upper limit as a result of the charging process, it performs a discharge process in which it discharges to the power line without charging until the power at the facility's power receiving point reaches the target power receiving point. The operation in the maintenance mode ends when the remaining energy storage reaches the lower limit. The energy storage device transmits discharge start information indicating that the discharge process has started or is scheduled to start, and maintenance end information indicating that it has finished operating in maintenance mode, to the power generation device or the communication device. The power generation device is characterized by its ability to adjust the power generated and supplied to the power line in accordance with the discharge start information and maintenance completion information received from the energy storage device or the communication device.

[0009] According to the above characteristic configuration, the power generator can receive discharge start information from the energy storage device or communication device indicating that the energy storage device has started or is scheduled to start discharge processing in maintenance mode. The power generator can also receive maintenance end information from the energy storage device or communication device indicating that it has finished operating in maintenance mode. The power generator then adjusts the generated power supplied to the power line according to the received discharge start information and maintenance end information. Here, while the energy storage device is performing discharge processing in maintenance mode, it does not recharge and discharges to the power line so that the power at the facility's power receiving point becomes the target power receiving point power. Therefore, while the energy storage device is performing discharge processing in maintenance mode, if the generated power supplied to the power line by the power generator increases, the power discharged to the power line by the energy storage device decreases (i.e., the rate at which the remaining energy decreases slows down, delaying the timing at which the remaining energy reaches the lower limit), and if the generated power supplied to the power line by the power generator decreases, the power discharged to the power line by the energy storage device increases (i.e., the rate at which the remaining energy decreases increases, accelerating the timing at which the remaining energy reaches the lower limit). As a result, by adjusting the power generated by the power generator to supply power lines while the energy storage device is performing the discharge process in maintenance mode, it is possible to adjust the timing at which the remaining energy storage capacity reaches its lower limit (i.e., the timing at which maintenance mode ends). Therefore, it is possible to provide a power supply system that can adjust the timing of when the maintenance mode of the energy storage device ends.

[0010] Another characteristic configuration of the power supply system according to the present invention is that the power generation device adjusts the power supplied to the power line to a predetermined target power generation power between the time it receives the discharge start information and the time it receives the maintenance completion information.

[0011] According to the above characteristic configuration, the power generator adjusts the power supplied to the power line to a predetermined target power after receiving discharge start information and before receiving maintenance completion information. For example, if the target power is reduced, the power discharged by the energy storage device to the power line increases, and the timing at which the remaining energy storage reaches its lower limit becomes earlier. Conversely, if the target power is increased, the power discharged by the energy storage device to the power line decreases, and the timing at which the remaining energy storage reaches its lower limit becomes later. As a result, the timing at which the maintenance mode of the energy storage device ends can be adjusted.

[0012] Another characteristic configuration of the power supply system according to the present invention is that a solar cell device is connected to the power line, The energy storage device transmits remaining energy information indicating the remaining energy storage amount to the power generation device or the communication device. The aforementioned power generation device is After receiving the discharge start information, the generated power supplied to the power line is adjusted to a predetermined target generated power. Subsequently, if it is determined that the timing at which the remaining energy storage capacity becomes a predetermined intermediate value greater than the lower limit, based on the remaining energy information, falls outside the predicted power generation time period when the power generated by the solar cell is expected to exceed a set value, the power generated and supplied to the power line is adjusted to a value equal to the load power of the power load. Subsequently, with the start time of the most recent predicted power generation period in the future as the target timing, when the target timing or a predetermined timing set a set time earlier than the target timing is reached, the power generated and supplied to the power line is adjusted to the target power generated until the maintenance completion information is received.

[0013] According to the above configuration, the timing of the end of the energy storage device's maintenance mode coincides with the start of the predicted power generation period when the solar panel's power generation is expected to exceed a set value. In other words, after the energy storage device's maintenance mode ends, there is a high probability that the solar panel's power generation will exceed the set value while the energy storage device is charging. As a result, the proportion of power received from the power grid in the energy storage device's charging power can be reduced.

[0014] Another characteristic configuration of the power supply system according to the present invention is that the target power generation is the minimum power generation of the power generation device.

[0015] According to the above characteristic configuration, by setting the target power generation to the minimum power generation of the power generation device, the power discharged from the power storage device to the power line increases, and the timing when the remaining power storage amount reaches the lower limit value is earlier. As a result, the timing when the maintenance mode of the power storage device ends arrives earlier. [[ID=X]]

[0016] Another characteristic configuration of the power supply system according to the present invention is that the power generation device includes an input reception unit that receives an input of the target power generation.

[0017] According to the above characteristic configuration, the target power generation can be freely set according to the information received by the input reception unit.

Brief Description of Drawings

[0018] [Figure 1] It is a diagram showing the configuration of the power supply system of the first embodiment. [Figure 2] It is a diagram showing the transition of the remaining power storage amount of the power storage device while the charging process and the discharging process in the maintenance mode are being performed in the power storage device. [Figure 3] It is a diagram showing the transition of the remaining power storage amount of the power storage device while the charging process and the discharging process in the maintenance mode are being performed in the power storage device. [Figure 4] It is a diagram showing the configuration of the power supply system of the second embodiment. [Figure 5] It is a diagram showing the transition of the remaining power storage amount of the power storage device and the power generation amount of the solar cell device while the charging process and the discharging process in the maintenance mode are being performed in the power storage device.

Modes for Carrying Out the Invention

[0019] <First Embodiment> Hereinafter, the power supply system according to the first embodiment of the present invention will be described. <U+ Figure 1 shows the configuration of the power supply system according to the first embodiment. As shown in the figure, the power supply system is installed in a facility 3 such as a dwelling or business office, and a power generator 9, a power storage device 14, and a power load 8 are connected to a power line 2 that is connected to a power grid 1. The power storage device 14 is connected to a first connection point P1 of the power line 2, and the power generator 9 and power load 8 are connected to a second connection point P2 of the power line 2. The first connection point P1 is located upstream of the second connection point P2 (i.e., closer to the power grid 1).

[0020] The power generation device 9 comprises a power generation unit 10 that generates electricity by consuming fuel gas, a power generation control unit 11 that controls the operation of the power generation unit 10, a power generation side communication unit 12, and an input receiving unit 18. The power generation device 9 is a fuel cell power generation device or an engine-driven power generation device. When the power generation device 9 is a fuel cell power generation device, the fuel gas supplied to the power generation unit 10 is either the supply gas supplied via the gas meter 13, or gas obtained by reforming the supply gas supplied via the gas meter 13. In the example shown in Figure 1, the power generation device 9 is supplied with raw fuel gas containing hydrocarbons such as city gas as the supply gas. Then, the power generation unit 10 generates electricity by consuming fuel gas containing hydrogen obtained by reforming the supply gas (raw fuel gas). The input receiving unit 18 of the power generation device 9 can receive information input. For example, the input receiving unit 18 can receive input of the target power generation of the power generation device 9, which will be described later, from a user. The power generation device 9 can communicate information with other devices connected to the information communication line 4 via the power generation side communication unit 12. For example, the power generation device 9 can communicate information with the power generation management server 5. The operation of the power generation unit 10 and the power generation side communication unit 12 is controlled by the power generation control unit 11.

[0021] A current measuring device 19 is installed between the first connection point P1 and the second connection point P2 in the power line 2 to measure the current value flowing from the first connection point P1 to the second connection point P2. The current measuring device 19 is constructed using, for example, a current transformer (instrument current transformer) used to detect the current value of power in the power line 2. The measurement result of the current measuring device 19 is transmitted to the power generation device 9, and the power generation control unit 11 derives the power value in the power line 2 from the product of the current value measured by the current measuring device 19 and a predetermined voltage value (for example, 100V, 200V, etc.).

[0022] The energy storage device 14 comprises an energy storage unit 15, an energy storage control unit 16, and an energy storage-side communication unit 17. The energy storage unit 15 can be configured using, for example, a secondary battery such as a lithium-ion battery. The energy storage control unit 16 of the energy storage device 14 controls the operation of the energy storage unit 15 to control the output power (discharge power) from the energy storage unit 15 to the power line 2 and the input power (charging power) from the power line 2 to the energy storage unit 15. The energy storage device 14 can communicate information with other devices connected to the information communication line 4 via the energy storage-side communication unit 17. The energy storage device 14 can communicate information with the energy storage management server 6. The operation of the energy storage unit 15 and the energy storage side communication unit 17 is controlled by the energy storage control unit 16.

[0023] The energy storage device 14 can adjust the discharge power and charge power of the energy storage unit 15 between the maximum discharge power and the maximum charge power and the power line 2. In this embodiment, the energy storage control unit 16 adjusts the discharge power and charge power of the energy storage unit 15 so that the power at the power receiving point of the facility 3 (power receiving point power) becomes a predetermined target power receiving point power. For example, the target power receiving point power is zero. Furthermore, after the maintenance mode described later has ended, that is, after the remaining charge of the energy storage unit 15 (state of charge (SOC)) has reached its lower limit, only charging will be performed so that the remaining charge of the energy storage unit 15 reaches a predetermined value.

[0024] Upstream of the first connection point P1 (on the power system 1 side) in the power line 2, a current measuring instrument 20 is provided to measure the current value flowing from the power system 1 side toward the first connection point P1. The current measuring instrument 20 is constructed using, for example, a current transformer (instrument current transformer) used to detect the current value of power in the power line 2. The measurement result of the current measuring instrument 20 is transmitted to the energy storage device 14, and the energy storage control unit 16 derives the power value in the power line 2 from the product of the current value measured by the current measuring instrument 20 and a predetermined voltage value (e.g., 100V, 200V, etc.). This derived power value corresponds to the power at the point of power reception of the facility 3 described above. Therefore, the energy storage control unit 16 adjusts the charging power and discharging power of the energy storage unit 15 based on the power value (power at the point of power reception) derived based on the current value measured by the current measuring instrument 20.

[0025] The power generation device 9 and the energy storage device 14 can communicate with each other directly or indirectly via the communication device 7. In the example shown in Figure 1, the power generation management server 5 and the energy storage management server 6 can communicate with each other. Furthermore, the power generation device 9 and the energy storage device 14 can communicate with the power generation management server 5 and the energy storage management server 6, which are external communication devices 7 of the facility 3.

[0026] The power generation control unit 11 sets the target power generation power of the power generation unit 10 in one of the first power generation mode, second power generation mode, or third power generation mode described below.

[0027] In the first power generation mode, the power generation control unit 11 sets the target power generation power of the power generation unit 10 so that the power supplied from the first connection point P1 to the second connection point P2 becomes zero, based on the current value measured by the current measuring instrument 20. In other words, in the first power generation mode, the power generation control unit 11 sets the target power generation power of the power generation unit 10 to the load power and magnitude of the power load 8. In this case, even if the charging power and discharging power of the energy storage device 14 are zero, the power at the power receiving point of facility 3 will be zero (i.e., the target power receiving point power). Therefore, when the power generation control unit 11 is adjusting the power generation power in the first power generation mode, it can be assumed that the remaining amount of energy stored in the energy storage device 14 does not increase or decrease.

[0028] In the second power generation mode, the power generation control unit 11 sets the target power generation of the power generation unit 10 to the maximum power generation. In this case, if the load power of the power load 8 is greater than the maximum power generation of the power generation unit 10, a power shortage occurs, and if the load power of the power load 8 is less than the maximum power generation of the power generation unit 10, a power surplus occurs. However, since the maximum power generation of the power generation unit 10 is more often greater than the load power of the power load 8, it can be assumed that a power surplus occurs more often when the power generation control unit 11 is adjusting the power generation in the second power generation mode. In that case, the energy storage device 14 charges the energy storage unit 15 in accordance with the power surplus, so that the power at the point of reception of facility 3 becomes zero (i.e., the target power at the point of reception). As a result, it can be assumed that the remaining energy in the energy storage device 14 tends to increase when the power generation control unit 11 is adjusting the power generation in the second power generation mode.

[0029] In the third power generation mode, the power generation control unit 11 sets the target power generation power of the power generation unit 10 to the minimum power generation power. In this case as well, if the load power of the power load 8 is greater than the minimum power generation power of the power generation unit 10, a power shortage will occur, and if the load power of the power load 8 is less than the minimum power generation power of the power generation unit 10, a power surplus will occur. However, since the power generation power of the power generation unit 10 is smaller than in the second power generation mode, the possibility of a power shortage is higher. In that case, the energy storage device 14 discharges from the energy storage unit 15 in response to the power shortage, so that the power at the receiving point of facility 3 becomes zero (i.e., the target power at the receiving point). As a result, when the power generation control unit 11 is adjusting the power generation power in the third power generation mode, it can be assumed that the remaining amount of energy stored in the energy storage device 14 tends to decrease.

[0030] Furthermore, the target power generation in the third power generation mode can be changed as appropriate. For example, the input receiving unit 18 of the power generation device 9 may set the value received from the user as the target power generation.

[0031] The energy storage device 14 may operate in a maintenance mode in which it charges the remaining energy in the energy storage unit 15 until it reaches its upper limit, and then discharges it until it reaches its lower limit. Specifically, when predetermined maintenance start conditions are met, the energy storage device 14 operates in a maintenance mode in which it performs a charging process in which it charges from the power line 2 without discharging until the remaining energy reaches its upper limit, and after the remaining energy reaches its upper limit as a result of the charging process, it discharges to the power line 2 without charging until the power at the power receiving point of the facility 3 reaches the target power receiving point. The device is configured to terminate operation in maintenance mode when the remaining energy reaches its lower limit.

[0032] The energy storage device 14 transmits discharge start information indicating that it has started or is scheduled to start discharge processing, and maintenance end information indicating that it has finished operating in maintenance mode, to the power generation device 9 or the communication device 7. The energy storage device 14 may also transmit charge start information indicating that it has started charging processing to the power generation device 9 or the communication device 7.

[0033] The power generator 9 can adjust the power generated by the power generation unit 10 between the maximum power generated (rated power generated) and the minimum power generated. The power generator 9 adjusts the power supplied to the power line 2 according to the discharge start information and maintenance completion information received from the energy storage device 14 or the communication device 7. Furthermore, if the power generator 9 receives charging start information from the energy storage device 14 or the communication device 7, it may adjust the power supplied to the power line 2 according to that charging start information, discharge start information, and maintenance completion information.

[0034] Specifically, the power generation control unit 11 of the power generation device 9 adjusts the power supplied to the power line 2 to a predetermined target power generation power from the time it receives discharge start information until it receives maintenance completion information. The target power generation power of the power generation unit 10 is determined according to whether the power generation device 9 is operating in the first power generation mode, second power generation mode, or third power generation mode described above.

[0035] The energy storage device 14 can adjust the discharge power and charge power of the energy storage unit 15 to the power line 2 between the maximum discharge power and the maximum charge power. As described above, the energy storage control unit 16 adjusts the discharge power and charge power of the energy storage unit 15 so that the power at the power receiving point of facility 3 (power receiving point power) becomes a predetermined target power receiving point power. For example, the target power receiving point power is zero. In other words, if a power generation shortage occurs as described above, the energy storage control unit 16 adjusts the discharge power from the energy storage unit 15 to the power line 2 so that the power generation shortage does not occur at the power receiving point (i.e., the power receiving point power determined based on the measurement result of the current meter 20 becomes zero). Also, if a power generation surplus occurs as described above, the energy storage control unit 16 adjusts the charge power from the energy storage unit 15 to the power line 2 so that the power generation surplus does not occur at the power receiving point (i.e., the power receiving point power determined based on the measurement result of the current meter 20 becomes zero).

[0036] As described above, although it varies depending on the magnitude of the load power of the power load 8, if the power generation control unit 11 sets the power generation power of the power generation unit 10 to the maximum power generation power, the remaining amount of energy stored in the energy storage unit 15 is expected to increase, and if the power generation control unit 11 sets the power generation power of the power generation unit 10 to the minimum power generation power, the remaining amount of energy stored in the energy storage unit 15 is expected to decrease.

[0037] The following describes the changes in the power generated by the power generation device 9 and the remaining energy stored in the energy storage device 14. Figure 2 shows the change in the remaining charge of the energy storage device 14 while the energy storage device 14 is performing charging and discharging processes in maintenance mode.

[0038] As described above, when predetermined maintenance start conditions are met, the energy storage device 14 operates in a maintenance mode that performs charging and discharging processes, and transmits charging start information to the power generation device 9 or the communication device 7 to indicate that the charging process has started. During the charging process, the energy storage control unit 16 performs charging with a predetermined charging power. For example, charging is performed using at least one of the power supplied from the power generation device 9 and the power supplied from the power system 1.

[0039] Then, after the power generator 9 receives charging start information from the energy storage device 14 or the communication device 7, and until it receives discharge start information, it sets the target power generation power of the power generation unit 10 in the second operating mode. In this embodiment, in the second power generation mode, the power generation control unit 11 sets the target power generation power of the power generation unit 10 to the maximum power generation power. In other words, when the target power generation power of the power generation unit 10 is set to the maximum power generation power, the aforementioned power generation surplus will increase, and it is expected that the power received from the power system 1 will decrease while the energy storage device 14 is performing the charging process.

[0040] In the example shown in Figure 2, the remaining energy storage capacity reaches its upper limit (SOC: 100%) after 3 hours have elapsed since the start of operation in maintenance mode. The energy storage device 14 then finishes the charging process and starts the discharging process, and transmits discharge start information to the power generation device 9 or the communication device 7 to indicate that the discharge process has started. After the power generation device 9 receives the discharge start information from the energy storage device 14 or the communication device 7, it sets the target power generation power of the power generation unit 10 in third power generation mode until it receives the maintenance completion information. In this embodiment, in third power generation mode, the power generation control unit 11 sets the target power generation power of the power generation unit 10 to minimum power generation power. When the power generation power of the power generation unit 10 is set to minimum power generation power, there is a high possibility of insufficient power generation occurring because the power generation power of the power generation unit 10 is less than the load power of the power load 8. Therefore, when the power generation unit 10 is operating in third power generation mode, the energy storage control unit 16 needs to increase the discharge power, for example, to make the power at the point of reception zero (target power at the point of reception). As a result, the amount of power discharged from the energy storage device 14 to the power line 2 increases, and the timing at which the remaining energy storage capacity reaches its lower limit, that is, the timing at which the maintenance mode of the energy storage device 14 ends, is shortened.

[0041] In the example shown in Figure 2, the remaining charge in the energy storage unit 15 decreases monotonically after 3 hours have elapsed, and at 12 hours, the remaining charge reaches its lower limit (SOC: 0%). The energy storage control unit 16 then terminates the discharge process (i.e., terminates the maintenance mode) and transmits maintenance completion information to the power generator 9 or communication device 7, indicating that operation in maintenance mode has ended.

[0042] When the power generator 9 receives maintenance completion information from the energy storage device 14 or the communication device 7, it can adjust the power generation to, for example, a first power generation mode or a second power generation mode.

[0043] Figure 3 shows the change in the remaining charge of the energy storage device 14 while the energy storage device 14 is performing charging and discharging processes in maintenance mode. In this example, the power generator 9 sets the target power generation power of the power generation unit 10 in the first power generation mode while the energy storage device 14 is performing the discharge process. In the first power generation mode, the power generation control unit 11 sets the target power generation power of the power generation unit 10 so that the power supplied from the first connection point P1 to the second connection point P2 becomes zero (target power receiving point power), which is determined based on the current value measured by the current measuring instrument 20. In other words, in the first power generation mode, the power generation control unit 11 sets the target power generation power of the power generation unit 10 to the same value as the load power of the power load 8. Therefore, the energy storage device 14 cannot discharge when the power generation power of the power generation unit 10 and the load power of the power load 8 are the same value, and the energy storage device 14 can only discharge when the power generation power of the power generation unit 10 (maximum power generation power) is less than the load power of the power load 8. Therefore, there is a problem in that the time required for the remaining energy storage to reach the lower limit (SOC: 0%) becomes very long.

[0044] As described above, while the energy storage device 14 is performing the discharge process in maintenance mode, the amount of power generated by the power generator 9 supplied to the power line 2 can be reduced, as shown in Figure 2, thereby increasing the power discharged by the energy storage device 14 to the power line 2 (i.e., increasing the rate at which the remaining energy storage capacity decreases). As a result, the timing at which the remaining energy storage capacity of the energy storage unit 15 reaches its lower limit (i.e., the timing at which the maintenance mode ends) can be brought about sooner.

[0045] <Second Embodiment> The power supply system of the second embodiment differs from the above embodiment in that the solar cell device 21 is connected to the power line 2. The power supply system of the second embodiment will be described below, but the same configuration as in the above embodiment will not be described.

[0046] Figure 4 shows the configuration of the power supply system of the second embodiment. The solar cell device 21 is connected to the first connection point P1 of the power line 2, the energy storage device 14 is connected to the second connection point P2 of the power line 2, and the power generator 9 and power load 8 are connected to the third connection point P3 of the power line 2. The first connection point P1 is located upstream of the second connection point P2 (i.e., closer to the power system 1), and the second connection point P2 is located upstream of the third connection point P3 (i.e., closer to the power system 1).

[0047] The power generation control unit 11 of the power generation device 9 sets the target power generation power of the power generation unit 10 in one of the first power generation mode, second power generation mode, or third power generation mode, similar to the embodiment described above.

[0048] The energy storage device 14, similar to the embodiment described above, operates in a maintenance mode in which, when predetermined maintenance start conditions are met, it performs a charging process in which it charges from the power line 2 without discharging until the remaining energy storage reaches the upper limit, and after the remaining energy storage reaches the upper limit due to the charging process, it performs a discharge process in which it discharges to the power line 2 without charging so that the power at the power receiving point of the facility 3 becomes the target power receiving point. The device is configured to terminate operation in maintenance mode when the remaining energy storage reaches the lower limit.

[0049] The energy storage device 14 transmits remaining energy information indicating the remaining energy to the power generation device 9 or the communication device 7. After receiving discharge start information, the power generation device 9 adjusts the power supplied to the power line 2 to a predetermined target power generation (i.e., the target power generation determined in the third power generation mode described above). Subsequently, if it is determined that the timing at which the remaining energy becomes a predetermined intermediate value greater than the lower limit, based on the remaining energy information, falls outside the predicted power generation time period, it adjusts the power supplied to the power line 2 to a value equal to the load power of the power load 8 (i.e., the target power generation determined in the first power generation mode described above). Subsequently, using the start time of the next predicted power generation time period in the future as the target timing, when it reaches the target timing or a predetermined timing set a set time earlier than the target timing, it adjusts the power supplied to the power line 2 to the target power generation (i.e., the target power generation determined in the third power generation mode described above) until it receives maintenance completion information.

[0050] Furthermore, if the power generator 9 determines, based on the remaining charge information, that the timing when the remaining charge reaches a predetermined intermediate value greater than the lower limit is within the predicted power generation time period, it should adjust the power supplied to the power line 2 to the target power generation power (i.e., the target power generation power determined in the third power generation mode described above) until it receives maintenance completion information.

[0051] The power generation device 9 can determine the predicted power generation time period for the solar cell device 21 based on information about the temporal changes in predicted solar radiation provided, for example, from a weather information server (not shown). The power generation device 9 can also receive remaining charge information from the energy storage device 14 or the communication device 7. The power generation device 9 then monitors the remaining charge of the energy storage device 14 and sets the target power generation power of the power generation unit 10 so that the timing when the remaining charge reaches its lower limit falls within the predicted power generation time period.

[0052] Thus, in the second embodiment, the timing of the end of the maintenance mode of the energy storage device 14 is during the predicted power generation period when the power generated by the solar cell 21 is expected to exceed a set value, or is close to the start of the predicted power generation period. In other words, after the maintenance mode of the energy storage device 14 ends, there is a high probability that the power generated by the solar cell 21 will exceed a set value while the energy storage device 14 is charging. As a result, the proportion of power received from the power grid 1 in the total power charged by the energy storage device 14 can be reduced.

[0053] Figure 5 shows the changes in the remaining charge of the energy storage device 14 and the amount of power generated by the solar cell device 21 while the energy storage device 14 is performing charging and discharging in maintenance mode. Note that the amount of power generated by the solar cell device 21 shown in Figure 5 is the amount of power generated in one hour.

[0054] After receiving discharge start information, the power generator 9 adjusts the power supplied to the power line 2 to the target power generation power. For example, after receiving discharge start information, the power generation control unit 11 sets the target power generation power of the power generation unit 10 in the third power generation mode. In other words, in the third power generation mode, the power generation control unit 11 sets the target power generation power of the power generation unit 10 to the minimum power generation power. Then, the energy storage control unit 16 increases the discharge power, for example, to make the power at the point of reception zero (target power at the point of reception). As a result, in the example shown in Figure 5, the remaining energy storage decreases monotonically after 3 o'clock.

[0055] In addition, after receiving discharge start information at 3:00, the power generation control unit 11 determines the predicted power generation time period for the solar cell device 21 to be between 8:00 and 18:00 on the first day.

[0056] Subsequently, the power generation control unit 11 monitors the remaining energy storage capacity based on the remaining energy information. If the power generation control unit 11 determines that the timing when the remaining energy storage capacity reaches a predetermined intermediate value greater than the lower limit (in the example shown in Figure 5, the intermediate value = SOC: 10%) falls outside the predicted power generation time period, it adjusts the power generated to be supplied to the power line 2 to a value equal to the load power of the power load 8. In the example shown in Figure 5, at 19:00, when the remaining energy storage capacity reaches the intermediate value (SOC: 10%), the power generation control unit 11 determines that the current time falls outside the predicted power generation time period and adjusts the power generated to be supplied to the power line 2 to a value equal to the load power of the power load 8 (i.e., the target power generated by the first power generation mode described above). The power generation control unit 11 also determines the next predicted power generation time period (i.e., the predicted power generation time period for the second day shown in Figure 5) as the new predicted power generation time period.

[0057] Subsequently, the power generation control unit 11 sets the start time of the next predicted power generation period in the future (i.e., 8:00 AM, the time of the predicted power generation period on the second day shown in Figure 5) as the target timing. When the target timing or a predetermined timing set a set time earlier than the target timing is reached, it adjusts the power supplied to the power line 2 to the target power until it receives maintenance completion information. In the example shown in Figure 5, when it is 7:00 AM, one hour (an example of a set time) earlier than 8:00 AM, which is the start time of the predicted power generation period on the second day, the power generation control unit 11 adjusts the power supplied to the power line 2 to the target power. As a result, the remaining charge in the energy storage device 14 decreases between 7:00 AM and 8:00 AM, and the remaining charge reaches its lower limit at 8:00 AM. After the maintenance mode is completed, i.e., after the remaining charge in the energy storage unit 15 reaches its lower limit, the energy storage device 14 only performs charging so that the remaining charge in the energy storage unit 15 reaches a predetermined value.

[0058] As described above, in the power supply system of the second embodiment, the timing at which the maintenance mode of the energy storage device 14 ends is close to the start of the predicted power generation period during which the power generated by the solar cell device 21 is expected to exceed a set value. In other words, after the maintenance mode of the energy storage device 14 ends, there is a high probability that the power generated by the solar cell device 21 will exceed a set value while the energy storage device 14 is charging. As a result, the proportion of power received from the power grid 1 in the power charged by the energy storage device 14 can be reduced.

[0059] <Another Embodiment> In the above embodiment, the configuration of the power supply system was described in detail, but the configuration can be changed as appropriate.

[0060] In the above embodiment, an example was described in which the communication device 7 is composed of a power generation management server 5 and a power storage management server 6, but the communication device 7 may also be composed of a single server.

[0061] In the above embodiment, an example was described in which the power generation device 9 and the energy storage device 14 communicate information via the communication device 7. However, the power generation device 9 and the energy storage device 14 may communicate information directly within the facility 3 without going through the communication device 7.

[0062] In the embodiments described above, the present invention has been explained with reference to several numerical examples, but these numerical values ​​are provided for illustrative purposes only and can be changed as appropriate.

[0063] The configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. Furthermore, the embodiments disclosed herein are illustrative, and the embodiments of the present invention are not limited thereto and can be modified as appropriate without departing from the purpose of the present invention. [Industrial applicability]

[0064] This invention can be used in a power supply system that can adjust the timing at which the maintenance mode of a power storage device ends. [Explanation of Symbols]

[0065] 1: Power system 2: Power lines 3: Facilities 5: Power generation management server (communication device 7) 6: Energy storage management server (communication device 7) 7: Communication equipment 8: Power load 9: Power generation equipment 14: Energy storage device 18: Input Reception Section 21: Solar cell device

Claims

1. A power supply system installed in a facility, in which a power generation device, a power storage device, and a power load are connected to a power line connected to the power grid, The power generation device and the energy storage device are capable of communicating information with each other directly or indirectly via a communication device. The energy storage device is configured to operate in a maintenance mode in which, when predetermined maintenance start conditions are met, it performs a charging process in which it charges from the power line without discharging until the remaining energy storage reaches the upper limit, and after the remaining energy storage reaches the upper limit as a result of the charging process, it performs a discharge process in which it discharges to the power line without charging until the power at the facility's power receiving point reaches the target power receiving point. The operation in the maintenance mode ends when the remaining energy storage reaches the lower limit. The energy storage device transmits discharge start information indicating that the discharge process has started or is scheduled to start, and maintenance end information indicating that it has finished operating in maintenance mode, to the power generation device or the communication device. The power generation device is a power supply system that adjusts the power generated to be supplied to the power line in accordance with the discharge start information and the maintenance completion information received from the energy storage device or the communication device.

2. The power supply system according to claim 1, wherein the power generation device adjusts the power generated to be supplied to the power line to a predetermined target power generated from the time it receives the discharge start information until it receives the maintenance completion information.

3. A solar cell device is connected to the aforementioned power line. The energy storage device transmits remaining energy information indicating the remaining energy storage amount to the power generation device or the communication device. The aforementioned power generation device is After receiving the discharge start information, the generated power supplied to the power line is adjusted to a predetermined target generated power. Subsequently, if it is determined that the timing at which the remaining energy storage capacity becomes a predetermined intermediate value greater than the lower limit, based on the remaining energy information, falls outside the predicted power generation time period when the power generated by the solar cell is expected to exceed a set value, the power generated and supplied to the power line is adjusted to a value equal to the load power of the power load. The power supply system according to claim 1, wherein, with the start time of the most recent predicted power generation time period in the future as the target timing, when the target timing or a predetermined timing set a set time earlier than the target timing is reached, the power generated to be supplied to the power line is adjusted to the target power generated until the maintenance completion information is received.

4. The power supply system according to claim 2 or 3, wherein the target power generation is the minimum power generation of the power generation device.

5. The power supply system according to claim 2 or 3, further comprising an input receiving unit for receiving the target power generation input of the power generation device.

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