Power management device and power management system

Abstract

To improve a technique to control multiple distributed power sources.SOLUTION: A power management device includes a control unit. A plurality of distributed power sources is electrically connected to a power grid. The control unit controls a first distributed power source among the plurality of distributed power sources to perform load following operation and a second distributed power source to perform operation to output power up to a predetermined value around a first timing at which power supplied from the power grid or reversely flowed to the power grid is changed from a first target value to a second target value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a power management device and a power management system.

Background Art

[0002] Techniques for controlling a plurality of distributed power sources arranged in a customer facility are known. For example, Patent Document 1 describes a management device that manages a storage battery or a solar power generation panel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Improvement of techniques for controlling a plurality of distributed power sources arranged in a customer facility is desired.

[0005] In view of this point, an object of the present disclosure is to improve techniques for controlling a plurality of distributed power sources.

Means for Solving the Problems

[0006] A power management device according to an embodiment of the present disclosure includes a control unit that controls, before and after a first timing at which power supplied from a power grid or fed back to the power grid is changed from a first target value to a second target value, among a plurality of distributed power sources electrically connected to the power grid, a first distributed power source to perform load-following operation and a second distributed power source to perform an operation of outputting power with a predetermined value as an upper limit.

[0007] A power management system according to an embodiment of the present disclosure includes a plurality of distributed power sources electrically connected to a power grid, and Before and after the first timing at which the power supplied from or reverse-fed to the power system is changed from the first target value to the second target value, among the plurality of distributed power sources, the first distributed power source performs load-following operation, and the second distributed power source performs operation to output power with a predetermined value as the upper limit. And a power management device that controls so as to perform the operation.

Effect of the Invention

[0008] According to an embodiment of the present disclosure, it is possible to improve the technology for controlling a plurality of distributed power sources.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0010] General power transmission and distribution operators are required to maintain the frequency of the power supplied to customer facilities and to stably supply power to customer facilities. Therefore, general power transmission and distribution operators need to secure adjustment power. The adjustment power is the ability to match the supply power supplied to the power system and the demand power of customer facilities. In recent years, a supply-demand adjustment market has been introduced to secure this adjustment power.

[0011] In the supply-demand adjustment market, for example, by using a virtual power plant (VPP), adjustment power can be secured. A virtual power plant is a virtual aggregation of distributed power sources respectively arranged in a plurality of customer facilities, regarded as one power plant. By increasing or decreasing the demand power of customer facilities through the virtual power plant, the supply power supplied to the power grid can be made to match the demand power of customer facilities. That is, adjustment power can be secured.

[0012] In the supply-demand adjustment market, for example, an aggregation coordinator directly conducts transactions with a general power transmission and distribution business operator. Further, the aggregation coordinator directly conducts transactions with a plurality of resource aggregators. A resource aggregator is a business operator that directly concludes a VPP service contract with a customer.

[0013] In the supply-demand adjustment market, when the aggregation coordinator receives a supply order from the general power transmission and distribution business operator, it allocates the power value received as the supply order from the general power transmission and distribution business operator and sends a supply order to each of the plurality of resource aggregators. When receiving the supply order, the resource aggregator calculates the demand power for securing adjustment power at each of the plurality of customer facilities. Each of the plurality of customer facilities controls the distributed power source so as to reach the demand power calculated by the resource aggregator in response to the request from the resource aggregator.

[0014] Here, there may be a case where a plurality of distributed power sources are arranged in a customer facility. When a plurality of distributed power sources are arranged in a customer facility, in order to accurately adjust the demand power of the customer facility in response to the request from the resource aggregator, an improvement in the technology for controlling a plurality of distributed power sources is desired. According to an embodiment of the present disclosure, the technology for controlling a plurality of distributed power sources can be improved.

[0015] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. In the embodiments according to the present disclosure, it is assumed that the distributed power source disposed in the customer facility is any one of a power storage device, a solar power generation device, or a fuel cell device. However, any distributed power source may be disposed in the customer facility. As another example, the distributed power source disposed in the customer facility may be a wind power generation device or the like.

[0016] Power management systems 1A and 1B according to an embodiment of the present disclosure as shown in FIG. 1 are each provided in a customer facility. In FIG. 1, solid lines connecting the respective blocks indicate power paths. Dashed lines connecting the respective blocks indicate communication paths. Hereinafter, when the power management systems 1A and 1B are not particularly distinguished, these are described as "power management system 1".

[0017] The power management system 1 is connected to the power grid 2 at the connection point 3. The connection point is also referred to as a "power reception point". The power grid 2 is, for example, a commercial power grid. In FIG. 1, the power management system 1A is connected to the power grid 2 at the connection point 3A. The power management system 1B is connected to the power grid 2 at the connection point 3B. In FIG. 1, two power management systems 1 are connected to the power grid 2. However, any number of power management systems 1 may be connected to the power grid 2.

[0018] Hereinafter, the power supplied from the power grid 2 to the power management system 1 via the connection point 3 or the power flowing back from the power management system 1 to the power grid 2 via the connection point 3 is described as "connection point power". The connection point power supplied from the power grid 2 to the power management system 1 via the connection point 3 is described as "power reception point power".

[0019] The network 4 may be any network including a mobile communication network and the Internet or the like. In FIG. 1, for the sake of illustration, a plurality of separated networks 4 are shown. However, the plurality of networks 4 may be one.

[0020] Server 5 is the server of a general power transmission and distribution operator. In order to ensure the adjustment power that matches the supplied power to the power grid 2 and the demanded power of the customer facilities, Server 5 transmits a supply instruction to Server 6 via Network 4.

[0021] Server 6 is the server of an aggregation coordinator. Server 6 receives a supply instruction from Server 5 via Network 4. Server 6 transmits a supply instruction to a plurality of Servers 7 according to the supply instruction received from Server 5.

[0022] Server 7 is the server of a resource aggregator. Server 7 receives a supply instruction from Server 6 via Network 4. When Server 7 receives a supply instruction, it calculates a target value described later for ensuring adjustment power at each of a plurality of customer facilities. These plurality of customers are customers who have directly concluded a VPP service contract with the resource aggregator. Server 7 transmits the calculated target value to a power management device 70 described later of the customer facility via Network 4.

[0023] Power management system 1 includes a plurality of distributed power sources. Power management system 1A includes a power storage device 40, a solar power generation device 50, and a fuel cell device 60 as a plurality of distributed power sources. Power management system 1B includes a power storage device 40 and a solar power generation device 50 as a plurality of distributed power sources. However, the combination of the plurality of distributed power sources included in power management system 1 is not limited to these. The plurality of distributed power sources included in power management system 1 may all be of the same type.

[0024] The plurality of distributed power sources included in power management system 1 are electrically connected to the power grid 2 via a power sensor 10 and a distribution board 20 described later. By including a plurality of distributed power sources, power management system 1 can function as part of a virtual power plant. The customers of power management system 1 have directly concluded a VPP service contract with the resource aggregator.

[0025] The distributed power sources included in the power management system 1 are distributed power sources capable of at least one of load following operation and output control operation.

[0026] Load following operation is to operate while outputting power that follows the load power so that the connection point power becomes a reference value. For the reference value, for example, a target value described later calculated by the server 7 is set. The load power is the power obtained by subtracting the power output from other distributed power sources from the power consumption of the load group 30. Other distributed power sources are distributed power sources other than the distributed power sources that perform load following operation. For example, other distributed power sources are distributed power sources that perform output control operation. The load power LP and the output power P1 of the distributed power source that performs load following operation are given by the following formula (1). Output power P1 = Load power LP - Reference value Load power LP = Power consumption of load group 30 - Output power of other distributed power sources Formula (1)

[0027] Distributed power sources capable of load following operation are, for example, a solar power generation device 50, a power storage device 40, and a fuel cell device 60.

[0028] Output control operation is to operate while outputting power with a predetermined power value as the upper limit. Distributed power sources capable of output control operation are, for example, a solar power generation device 50, a power storage device 40, and a fuel cell device 60.

[0029] In addition to a plurality of distributed power sources, the power management system 1 includes a power sensor 10, a distribution board 20, a load group 30, and a power management device 70.

[0030] The power sensor 10 is arranged in the circuit connecting between the connection point 3 and the distribution board 20. The power sensor 10 measures the power flowing between the connection point 3 and the distribution board 20, that is, the connection point power. The power sensor 10 transmits the measurement result of the connection point power to the power management device 70.

[0031] The distribution board 20 is arranged between the connection point 3 and the load group 30 and a plurality of distributed power sources. In other words, the distribution board 20 is on the secondary side of the connection point 3 in the circuit and is arranged on the primary side of the load group 30 and a plurality of distributed power sources. For example, the distribution board 20 of the power management system 1A is arranged between the connection point 3A, the load group 30, the energy storage device 40, the solar power generation device 50, and the fuel cell device 60. The distribution board 20 of the power management system 1B is arranged between the connection point 3B, the load group 30, the energy storage device 40, and the solar power generation device 50.

[0032] The distribution board 20 electrically connects the connection point 3, a plurality of distributed power sources, and the load group 30. When a leakage current or the like is detected, the distribution board 20 electrically disconnects the connection point 3, a plurality of distributed power sources, and the load group 30. For example, the distribution board 20 of the power management system 1A electrically connects the connection point 3A, the load group 30, the energy storage device 40, the solar power generation device 50, and the fuel cell device 60. When a leakage current or the like is detected, the distribution board 20 of the power management system 1A electrically disconnects the connection point 3A, the load group 30, the energy storage device 40, the solar power generation device 50, and the fuel cell device 60. For example, the distribution board 20 of the power management system 1B electrically connects the connection point 3B, the load group 30, the energy storage device 40, and the solar power generation device 50. When a leakage current or the like is detected, the distribution board 20 of the power management system 1B electrically disconnects the connection point 3B, the load group 30, the energy storage device 40, and the solar power generation device 50.

[0033] The load group 30 is electrically connected to the power system 2 via the distribution board 20 and the connection point 3. Electric power is supplied to the load group 30 via the distribution board 20. The load group 30 includes at least one load device. The load device is, for example, an electrical device used in a consumer facility. The load device consumes the electric power supplied via the distribution board 20.

[0034] The energy storage device 40 includes an energy storage battery 41 and a power conversion device 42.

[0035] The energy storage battery 41 is configured to include a secondary battery such as a lithium-ion battery, for example.

[0036] The power conversion device 42 is a so-called power conditioning system (PCS). The power conversion device 42 converts the DC power stored in the storage battery 41 into AC power. The power conversion device 42 supplies the converted AC power to the distribution board 20. Further, the power conversion device 42 converts the AC power supplied from the distribution board 20 into DC power. The power conversion device 42 charges the storage battery 41 with the converted DC power.

[0037] The power conversion device 42 performs load following operation according to the control signal received from the power management device 70. When the power conversion device 42 performs load following operation, it acquires the measurement result of the connection point power of the power sensor 10 from the power management device 70. The power conversion device 42 performs load following operation by controlling the discharge power of the storage battery 41 based on the measurement result of the connection point power of the power sensor 10. Further, the power conversion device 42 may be able to perform output control operation according to the control signal received from the power management device 70.

[0038] The solar power generation device 50 includes a solar cell 51 and a power conversion device 52.

[0039] The solar cell 51 generates DC power by light energy. The solar cell 51 is configured to include, for example, at least one string. The strings are configured by connecting a plurality of solar cell modules in series.

[0040] The power conversion device 52 is a so-called power conditioning system (PCS). The power conversion device 52 converts the DC power generated by the solar cell 51 into AC power. The power conversion device 52 supplies the converted AC power to the distribution board 20.

[0041] The power conversion device 52 performs an output control operation according to a control signal received from the power management device 70. The power conversion device 52 may be capable of performing a load following operation according to a control signal received from the power management device 70. When the power conversion device 52 performs a load following operation, it acquires the measurement result of the connection point power of the power sensor 10 from the power management device 70. The power conversion device 52 performs a load following operation by controlling the solar cell 51 based on the measurement result of the connection point power of the power sensor 10.

[0042] The fuel cell device 60 includes a fuel cell 61 and a power conversion device 62.

[0043] The fuel cell 61 is configured to include, for example, a solid oxide fuel cell (SOFC), a polymer electrolyte fuel cell (PEFC), a phosphoric acid fuel cell (PAFC), or a molten carbonate fuel cell (MCFC).

[0044] The power conversion device 62 is a so-called power conditioner (PCS). The power conversion device 62 converts the DC power generated by the fuel cell 61 into AC power. The power conversion device 62 supplies the converted AC power to the distribution board 20.

[0045] The power conversion device 62 performs an output control operation according to a control signal received from the power management device 70. The power conversion device 62 may be capable of performing a load following operation according to a control signal received from the power management device 70. When the power conversion device 62 performs a load following operation, it acquires the measurement result of the connection point power of the power sensor 10 from the power management device 70. The power conversion device 62 performs a load following operation by controlling the power generation power of the fuel cell 61 based on the measurement result of the connection point power of the power sensor 10.

[0046] The power management device 70 is, for example, a HEMS (HEMS: Home Energy Management System). However, the power management device 70 is not limited to a HEMS. The power management device 70 may be any information processing device. The power management device 70 includes a communication unit 71, a storage unit 72, and a control unit 73.

[0047] The communication unit 71 is configured to include at least one communication module connectable to the network 4. The communication module is, for example, a communication module compliant with a standard such as a wired LAN (Local Area Network) or a wireless LAN. The communication unit 71 is connected to the network 4 via a wired LAN or a wireless LAN by the communication module.

[0048] The communication unit 71 is configured to include at least one communication module capable of communicating with the power sensor 10 and the distributed power source. The communication module is, for example, a communication module compliant with the communication standard between the power management device 70 and the power sensor 10 and the distributed power source. The communication between the power management device 70 and the power sensor 10 and the distributed power source is configured to include at least one of wired and wireless.

[0049] The storage unit 72 is configured to include at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or a combination of at least two of these. The semiconductor memory is, for example, a RAM (Random Access Memory) or a ROM (Read Only Memory). The RAM is, for example, an SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory). The ROM is, for example, an EEPROM (Electrically Erasable Programmable Read Only Memory). The storage unit 72 may function as a main storage device, an auxiliary storage device, or a cache memory. The storage unit 72 stores data used for the operation of the power management device 70 and data obtained by the operation of the power management device 70.

[0050] The control unit 73 is configured to include at least one processor, at least one dedicated circuit, or a combination thereof. The processor is, for example, a general-purpose processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or a dedicated processor specialized for specific processing. The dedicated circuit is, for example, an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). The control unit 73 executes processes related to the operation of the power management device 70 while controlling each part of the power management device 70.

[0051] The control unit 73 receives the measurement result of the connection point power from the power sensor 10 via the communication unit 71. The control unit 73 may transmit the measurement result of the connection point power to any distributed power source among the plurality of distributed power sources included in the power management system 1 via the communication unit 71. As an example, the control unit 73 may transmit the measurement result of the connection point power to at least a distributed power source performing load following operation among the plurality of distributed power sources included in the power management system 1 via the communication unit 71. For example, in the power management system 1A, the control unit 73 may transmit the measurement result of the connection point power to each of the power storage device 40, the solar power generation device 50, and the fuel cell device 60. In the power management system 1B, the control unit 73 may transmit the measurement result of the connection point power to each of the power storage device 40 and the solar power generation device 50.

[0052] The control unit 73 receives a target value from the server 7 via the network 4 by means of the communication unit 71. The target value is either the target value of the power supplied from the power grid 2 to the power management system 1 or the target value of the power flowing in reverse from the power management system 1 to the power grid 2. Hereinafter, the target value received by the control unit 73 from the server 7 is described as the "first target value" or the "second target value". The second target value is the target value received after the first target value. Also, when the power flowing from the power grid 2 to the power management system 1 via the connection point 3 is taken as the positive direction, the first target value and the second target value are set to be smaller than the power consumption of the load group 30.

[0053] <Control Processing of the First Target Value> When the control unit 73 receives the first target value from the server 7, it controls the connection point power to reach the first target value within the response time after receiving the first target value. The response time is preset, for example, by the contract between the consumers of the power management system 1 and the resource aggregator. The response time is, for example, 10 seconds, 5 minutes, 15 minutes, or 45 minutes. Also, the control unit 73 controls the connection point power to continuously reach the first target value for a predetermined time. The predetermined time is preset, for example, by the contract between the consumers of the power management system 1 and the resource aggregator. The predetermined time is, for example, 5 minutes, 30 minutes, or 3 hours, etc.

[0054] First, the control unit 73 controls one of the plurality of distributed power sources arranged in the consumer facility to perform load-following operation and another to perform output control operation. In this embodiment, the control unit 73 transmits a control signal to one of the first distributed power sources via the communication unit 71 to control the one first distributed power source to perform load-following operation with the first target value as the reference value. Also, the control unit 73 transmits a control signal to one of the second distributed power sources via the communication unit 71 to control the one second distributed power source to perform output control operation with the first power value as the upper limit. The first power value may be a predetermined percentage of the rated power of the second distributed power source.

[0055] The first distributed power source and the second distributed power source may be preset from among a plurality of distributed power sources arranged in the customer facility. When a plurality of distributed power sources capable of both load-following operation and output control operation are arranged in the customer facility, a distributed power source with a faster response speed may be preferentially set as the first distributed power source. The response speed is the speed at which the output power changes following the fluctuation of the load power as shown in the above formula (1). Further, when a distributed power source that generates power using natural energy is arranged in the customer facility, the distributed power source that generates power using natural energy may be preferentially set as the second distributed power source.

[0056] For example, in the power management system 1A, the solar power generation device 50, the power storage device 40, and the fuel cell device 60 are capable of both load-following operation and output control operation. Here, the power storage device 40 has a faster response speed for load-following operation than the solar power generation device 50 and the fuel cell device 60. Further, the solar power generation device 50 is a distributed power source that generates power using natural energy such as sunlight. Therefore, the power storage device 40 is set as the first distributed power source. Further, the solar power generation device 50 is set as the second distributed power source. When the first target value is received, the fuel cell device 60 may be stopped depending on the power consumption of the load group 30. Or, the fuel cell device 60 may be set as the second distributed power source instead of the solar power generation device 50.

[0057] For example, in the power management system 1B, the solar power generation device 50 and the power storage device 40 are capable of both load-following operation and output control operation. Similar to or the same as the example of the power management system 1A, the power storage device 40 is set as the first distributed power source. Further, the solar power generation device 50 is set as the second distributed power source.

[0058] FIG. 2 shows an example of the control state in the power management system 1A. The vertical axis indicates the connection point power [W]. The horizontal axis indicates time. In the axis of the connection point power [W] shown in FIG. 2, the direction in which power flows from the power grid 2 to the power management system 1 is the positive direction. In FIG. 2, the connection point power [W] is shown by a solid line. Further, the power consumption of the load group 30 is shown by a dashed line.

[0059] In FIG. 2, the power storage device 40 is set as the first distributed power source. The discharge power of the power storage device 40, that is, the output power, is indicated by hatching. Also, the photovoltaic power generation device 50 is set as the second distributed power source. The output power of the photovoltaic power generation device 50 is indicated by hatching different from that of the power storage device 40. In FIG. 2, the fuel cell device 60 is stopped.

[0060] In FIG. 2, before time t0, the control unit 73 may or may not perform control according to the VPP service contract, or may perform control according to the VPP service. Alternatively, the control unit 73 may also perform control such that the connection point power becomes the first target value even before time t0. At time t0, the control unit 73 receives the first target value from the server 7 and controls so that the connection point power becomes the first target value. For example, at time t0, the control unit 73 transmits a control signal to the power storage device 40, which is the first distributed power source, by the communication unit 71, and controls the power storage device 40 to perform load following operation with the first target value as the reference value. Also, at time t0, the control unit 73 transmits a control signal to the photovoltaic power generation device 50, which is the second distributed power source, by the communication unit 71, and controls the photovoltaic power generation device 50 to perform output control operation to output power with the first power value as the upper limit. In FIG. 2, the first power value is α [W]. Here, the power generation power of the photovoltaic power generation device 50 changes depending on the solar radiation amount. Therefore, after time t0, the output power of the photovoltaic power generation device 50 may temporarily decrease from α [W], which is the upper limit value, the first power value. Even if the output power of the photovoltaic power generation device 50 temporarily decreases in this way, the power storage device 40 performs load following operation, and thus the connection point power is controlled to become the first target value.

[0061] <Control Process from the First Target Value to the Second Target Value> After receiving the first target value, the control unit 73 can receive, via the network 4 from the server 7, a target value different from the first target value by the communication unit 71. The target value received after receiving the first target value is described as the "second target value". When the power flowing from the power system 2 to the power management system 1 through the connection point 3 is in the positive direction, the second target value is set to be smaller than the power consumption of the load group 30. When the control unit 73 receives the second target value, it controls the connection point power to reach the second target value.

[0062] Here, before and after the first timing at which the control unit 73 changes the connection point power from the first target value to the second target value, among the plurality of distributed power sources, the control unit 73 controls one first distributed power source to perform load following operation and one second distributed power source to perform output control operation. In this embodiment, the control unit 73 transmits a control signal to one second distributed power source by the communication unit 71, so that before and after the first timing, one second distributed power source performs output control operation to output power with the second power value (predetermined value) as the upper limit. The second power value may be smaller than the first power value. The second power value may be zero [W]. Alternatively, the second power value may be set independently regardless of the first power value. When the second power value can estimate a certain power value that the second distributed power source can output, the second power value may be a certain power value that the second distributed power source can output.

[0063] Hereinafter, an example of the control process before and after the first timing will be described. Hereinafter, the timing before the first timing is described as the "second timing". Also, the timing after the first timing is described as the "third timing".

[0064] First, the control unit 73 controls the second distributed power source to perform an output control operation of outputting power with the second power value as the upper limit at the second timing by transmitting a control signal to the second distributed power source through the communication unit 71. For example, in FIG. 2, the time t1 corresponds to the second timing. The control unit 73 controls the solar power generation device 50, which is the second distributed power source, to perform an output control operation with the β [W] of the second power value as the upper limit at the time t1 by transmitting a control signal to the solar power generation device 50 through the communication unit 71. The β [W] of the second power value is smaller than the α [W] of the first power value. Also, the control unit 73 controls the power storage device 40, which is the first distributed power source, to perform a load following operation with the first target value as the reference value at the time t1.

[0065] Next, the control unit 73 controls the first distributed power source to perform a load following operation with the second target value as the reference value at the first timing by transmitting a control signal to the first distributed power source through the communication unit 71. For example, in FIG. 2, the time t2 corresponds to the first timing. The control unit 73 controls the power storage device 40, which is the first distributed power source, to perform a load following operation with the second target value as the reference value at the time t2 by transmitting a control signal to the power storage device 40 through the communication unit 71. When the reference value of the power storage device 40 performing the load following operation at the first timing changes from the first target value to the second target value, the connection point power becomes the second target value at the time t2 corresponding to the first timing. In FIG. 2, when the direction of the power flowing from the power grid 2 to the power management system 1 is the positive direction, the second target value is smaller than the first target value.

[0066] <Control Process of Second Target Value> Furthermore, the control unit 73 controls the second distributed power source to perform an output control operation of outputting power with a third power value as the upper limit at the third timing by transmitting a control signal to the second distributed power source through the communication unit 71. The third power value may be a predetermined ratio of the rated power of the second distributed power source. Alternatively, the control unit 73 may set the third power value based on, for example, the maximum power value in the maximum power point tracking control as described later. The third power value may be greater than the second power value, or may be the same as the second power value. Also, the third power value may be the same as the first power value, or may be a value different from the first power value. For example, in FIG. 2, time t3 corresponds to the third timing. The control unit 73 controls the solar power generation device 50, which is the second distributed power source, to perform an output control operation of outputting power with γ [W] of the third power value as the upper limit by transmitting a control signal to the solar power generation device 50 through the communication unit 71. Also, at time t3, the control unit 73 controls the power storage device 40, which is the first distributed power source, to perform a load following operation with the second target value as the reference value.

[0067] Here, when the second distributed power source is the solar power generation device 50, the control unit 73 may calculate the maximum power value that can be output when the solar power generation device 50 operates in the maximum power point tracking control (MPPT) after the third timing. The maximum power value is the power value at the maximum operating point. Furthermore, the control unit 73 may calculate a differential power value obtained by subtracting the second target value from the power consumption of the load group 30. The control unit 73 may set the third power value to be equal to or less than the maximum power value and the differential power value. By setting the third power value to be equal to or less than the maximum power value and the differential power value in the maximum power point tracking control in this way, the discharge power, that is, the output power of the power storage device 40, which is the first distributed power source, can be reduced. As a result, the amount of power used for charging the power storage device 40 can be reduced.

[0068] Thus, in this embodiment, the control unit 73 controls one first distributed power source among a plurality of distributed power sources to perform load following operation before and after the first timing at which the connection point power changes from the first target value to the second target value. For example, in FIG. 2, only the power storage device 40 performs load following operation between time t1 and time t3 before and after the first timing. Here, if a plurality of distributed power sources perform load following operation, for example, when a plurality of distributed power sources perform feedback control simultaneously, an under-damping response or an over-damping response is likely to occur at the first timing. In particular, when the power consumption of the load group 30 changes greatly such as from a decrease to an increase at time t2 corresponding to the change timing as shown in FIG. 2, an under-damping response or an over-damping response is likely to occur. In this embodiment, since there is one first distributed power source performing load following operation, an under-damping response or an over-damping response is less likely to occur at the first timing than when there are a plurality of distributed power sources performing load following operation. Therefore, the connection point power can be adjusted with high accuracy.

[0069] Furthermore, in this embodiment, the control unit 73 controls one second distributed power source to perform an output control operation in which the power output has an upper limit of a second power value (predetermined value) before and after the first timing at which the connection point power changes from the first target value to the second target value. For example, in FIG. 2, between time t1 and time t3 before and after the first timing, the solar power generation device 50 performs an output control operation in which the power output has an upper limit of β [W] of the second power value. Here, since the second power value is smaller than the first power value, even if the second distributed power source generates power using natural energy such as the solar power generation device 50, the power output by the second distributed power source is stabilized. By stabilizing the power output by the second distributed power source before and after the first timing, the first distributed power source performing load following operation can accurately follow the load power as shown in the above formula (1). For example, between time t1 and time t3 as shown in FIG. 2, by stabilizing the power output by the solar power generation device 50 to β [W] of the second power value, the power storage device 40 can accurately follow the load power. Therefore, the connection point power can be adjusted with high accuracy.

[0070] Here, the control unit 73 may set the first interval from the second timing to the first timing to be equal to or longer than the settling time when the change value of the output power of the first distributed power source corresponds to the difference between the first power value and the second power value. The settling time is the time until the swing width of the connection point power falls within a predetermined range in the transient response when the change value of the output power of the first distributed power source corresponds to the power value of the difference between the first power value and the second power value. The predetermined range may be set based on the allowable power swing width at the connection point power. The predetermined range is, for example, in the range of ±5% of the second power value. For example, in the configuration shown in FIG. 2, the control unit 73 sets the first interval T1 to be equal to or longer than the settling time when the discharge power of the power storage device 40, which is the first distributed power source, that is, the change value of the output power corresponds to the power value of the difference between α [W] of the first power value and β [W] of the second power value. The first interval T1 is the interval from the time t1 corresponding to the second timing to the time t2 corresponding to the first timing. With such a configuration, it becomes difficult for an under-damped response or an over-damped response to occur at the first timing. The control unit 73 may set the upper limit value of the first interval based on the response time and the predetermined time described above.

[0071] Further, the control unit 73 may set the second interval from the first timing to the third timing to be equal to or longer than the settling time when the change value of the output power of the first distributed power source corresponds to the power value that is the difference between the first target value and the second target value. The settling time is the time until the swing width of the connection point power falls within a predetermined range in the transient response when the change value of the output power of the first distributed power source corresponds to the power value that is the difference between the first target value and the second target value. The predetermined range may be set based on the allowable swing width of the power at the connection point. The predetermined range is, for example, in the range of ±5% of the second target value. For example, in the configuration shown in FIG. 2, the control unit 73 sets the second interval T2 to be equal to or longer than the settling time when the discharge power of the power storage device 40, which is the first distributed power source, that is, the change value of the output power corresponds to the difference between the first target value and the second target value. That is, the control unit 73 sets the second interval T2 to be equal to or longer than the settling time until the power received at the connection point 3 changes from the first target value and captures the second target value by changing the discharge power of the power storage device 40, which is the first distributed power source, that is, the output power. The second interval T2 is the interval from the time t2 corresponding to the first timing to the time t3 corresponding to the third timing. With such a configuration, it becomes difficult for an under-damped response or an over-damped response to occur at the first timing. The control unit 73 may set the upper limit value of the second interval based on the response time and the predetermined time described above.

[0072] So far, for the sake of simplicity, in the power management system 1A, an example of controlling two distributed power sources, namely the first distributed power source and the second distributed power source, has been described. However, in the power management system 1A, distributed power sources other than the first distributed power source and the second distributed power source may be controlled. In the power management system 1A, for example, the third distributed power source among a plurality of distributed power sources may be controlled. For example, in the power management system 1A, when the power consumption of the load group 30 is equal to or greater than a predetermined power threshold at the fourth timing after the third timing, the control unit 73 may control the third distributed power source to perform an output control operation. The control unit 73 may control the third distributed power source to perform an output control operation of outputting power with the fourth power value as the upper limit by transmitting a control signal to the third distributed power source through the communication unit 71. The third distributed power source is a fuel cell device 60. The power threshold may be set based on the second power value and the second target value.

[0073] FIG. 3 shows another example of the control state in the power management system 1A. The configuration shown in FIG. 3 is a continuation of the configuration shown in FIG. 2. Time t4 corresponds to the fourth timing. At time t4, the control unit 73 determines that the power consumption of the load group 30 is equal to or greater than a predetermined power threshold when it is greater than a predetermined value by a certain amount compared to the value obtained by adding the maximum power value of the second distributed power source at time t4 and the second target value. The predetermined value may be set based on the desired accuracy for adjusting the connection point power. The control unit 73 controls the fuel cell device 60, which is the third distributed power source, to perform an output control operation of outputting power with δ [W] of the fourth power value as the upper limit at time t4 by transmitting a control signal to the fuel cell device 60 through the communication unit 71.

[0074] In this way, the fourth timing at which the third distributed power source outputs power is set after the third timing. As a result, before the fourth timing, the distributed power sources performing output control operation are only the second distributed power source, so the possibility of the connection point power fluctuating is reduced. Since the possibility of the connection point power fluctuating is reduced, the accuracy with which the first distributed power source follows the fluctuation of the reference value is improved. Since the accuracy with which the first distributed power source follows the fluctuation of the reference value is improved, the connection point power can be accurately adjusted after the first timing. For example, in FIG. 3, the connection point power can be accurately adjusted after the time t2 corresponding to the first timing.

[0075] Also, the rate of change of the output power of the fuel cell device 60 is slower than the rate of change of the output power of the photovoltaic power generation device 50. Therefore, it is possible to increase the output power of the second distributed power source at high speed by performing output control operation on the photovoltaic power generation device 50 as the second distributed power source in advance rather than the fuel cell device 60. Since the output power of the second distributed power source increases at high speed, the discharge power amount, that is, the output power amount, of the power storage device 40 which is the first distributed power source can be reduced. As a result, the amount of charging power used by the power storage device 40 can be reduced. Also, by outputting power from the third distributed power source in addition to the second distributed power source, the discharge power amount, that is, the output power amount, of the power storage device 40 which is the first distributed power source can be reduced. As a result, the amount of charging power used by the power storage device 40 can be reduced. Thereby, the charge and discharge cycle count of the power storage device 40 can be reduced, and deterioration of the power storage device 40 can be suppressed.

[0076] <Modification Example> In FIG. 2, when the direction of the power flowing from the power system 2 to the power management system 1 is defined as the positive direction, the second target value is smaller than the first target value. However, if the second target value is different from the first target value, it may be larger than the first target value. Even if the second target value is larger than the first target value, the control unit 73 can accurately adjust the connection point power by executing the same or similar processing as described above. For example, FIG. 4 shows another example of the control state in the power management system 1A. The configuration shown in FIG. 4 is different from the configuration shown in FIG. 2 in that the second target value is larger than the first target value. Except for the first target value and the second target value, the configuration shown in FIG. 4 is the same as the configuration shown in FIG. 2. Also in the configuration shown in FIG. 4, the control unit 73 can accurately adjust the connection point power by executing the same or similar processing as described above.

[0077] (Operation of Power Management System) FIG. 5 is a sequence diagram showing an operation example of the power management system shown in FIG. 1. Hereinafter, it is assumed that the first distributed power source is the energy storage device 40. Also, it is assumed that the second distributed power source is the solar power generation device 50.

[0078] The server 5 of the general power transmission and distribution utility transmits a supply command to the server 6 via the network 4 (step S1).

[0079] When the server 6 of the aggregation coordinator receives the supply command from the server 5 via the network 4, it transmits the supply command to the server 7 via the network 4 (step S2).

[0080] The server 7 of the resource aggregator transmits the first target value to the power management device 70 via the network 4 (step S3).

[0081] In the power management device 70, the control unit 73 receives the first target value from the server 7 via the network 4 by means of the communication unit 71. The control unit 73 controls the power storage device 40 to perform load following operation with the first target value as the reference value by transmitting a control signal to the power storage device 40 via the communication unit 71 (step S4). Further, the control unit 73 controls the solar power generation device 50 to perform output control operation with the first power value as the upper limit value by transmitting a control signal to the solar power generation device 50 via the communication unit 71 (step S5).

[0082] When the power storage device 40 receives a control signal from the power management device 70, it performs load following operation with the first target value as the reference value (step S6).

[0083] When the solar power generation device 50 receives a control signal from the power management device 70, it performs output control operation with the first power value as the upper limit value (step S7).

[0084] The server 5 of the general power transmission and distribution utility transmits a supply command to the server 6 via the network 4 (step S8).

[0085] When the server 6 of the aggregation coordinator receives a supply command from the server 5 via the network 4, it transmits the supply command to the server 7 via the network 4 (step S9).

[0086] The server 7 of the resource aggregator transmits the second target value to the power management device 70 via the network 4 (step S10).

[0087] In the power management device 70, the control unit 73 receives the second target value from the server 7 via the network 4 by means of the communication unit 71. The control unit 73 controls the solar power generation device 50 to perform output control operation with the second power value as the upper limit at the second timing by transmitting a control signal to the solar power generation device 50 via the communication unit 71 (step S11).

[0088] When the photovoltaic power generation device 50 receives a control signal from the power management device 70, it performs an output control operation with the second power value as the upper limit at the second timing (step S12).

[0089] In the power management device 70, the control unit 73 controls the power storage device 40 to perform a load following operation with the second target value as the reference value at the first timing by transmitting a control signal to the power storage device 40 through the communication unit 71 (step S13).

[0090] When the power storage device 40 receives a control signal from the power management device 70, it performs a load following operation with the two target values as the reference value at the first timing (step S14).

[0091] In the power management device 70, the control unit 73 controls the photovoltaic power generation device 50 to perform an output control operation with the third power value as the upper limit at the third timing by transmitting a control signal to the photovoltaic power generation device 50 through the communication unit 71 (step S15).

[0092] When the photovoltaic power generation device 50 receives a control signal from the power management device 70, it performs an output control operation with the third power value as the upper limit at the third timing (step S16).

[0093] The processing of step S4 and the processing of step S5 may be executed at the same timing. Alternatively, the processing of step S4 may be executed before the processing of step S5.

[0094] The processing of steps S11, S13, and S15 may be executed at the same timing as long as the processing of step S12 is executed at the second timing, the processing of step S14 is executed at the first timing, and the processing of step S16 is executed at the third timing. Alternatively, the processing of steps S11, S13, and S15 may be executed in a different order.

[0095] When the second target value received in the process of step S10 is different from the first target value received in the process of step S3, the power management device 70 may execute the processes of steps S11, S13, and S15. That is, when the second target value and the first target value are the same, the power management device 70 does not have to execute the processes of steps S11, S13, and S15. In this case, the power storage device 40 does not have to execute the process of step S14. The solar power generation device 50 does not have to execute the processes of steps S12 and S16.

[0096] As described above, in this embodiment, the power management device 70 controls one first distributed power source among a plurality of distributed power sources to perform load following operation before and after the first timing at which the connection point power changes from the first target value to the second target value. With such a configuration, as described above, the connection point power can be adjusted with high accuracy. Further, when a plurality of distributed power sources are respectively arranged in a consumer facility at different times, the communication protocols between the respective power conversion devices of the plurality of distributed power sources and the power management device 70 are not necessarily the same standard. In this case, if the power management device 70 is configured to be able to appropriately allocate the output power to the plurality of distributed power sources and instruct load following operation, the configuration of the power management device 70 becomes complicated. In this embodiment, by having one first distributed power source perform load following operation, it is possible to suppress the complication of the configuration of the power management device 70.

[0097] Therefore, according to this embodiment, the technology for controlling a plurality of distributed power sources can be improved.

[0098] Furthermore, in the present embodiment, the control unit 73 controls such that, before and after the first timing at which the connection point power is changed from the first target value to the second target value, one second distributed power source performs an output control operation of outputting power with an upper limit of a second power value (predetermined value). Here, as described above, since the second power value is smaller than the first power value, even if the second distributed power source generates power using natural energy such as the solar power generation device 50, the power output by the second distributed power source is stabilized. With such a configuration, the power storage device 40 can accurately follow the load power. Therefore, the connection point power can be accurately adjusted.

[0099] Also, in the present embodiment, the first distributed power source may be the power storage device 40. Further, the second distributed power source may be the solar power generation device 50. Here, as described above, the power generation power of the solar power generation device 50 changes depending on the solar radiation amount. Therefore, as described above with reference to FIG. 2, after the time t0, the output power of the solar power generation device 50 may temporarily decrease from the first power value which is the upper limit value by α [W]. Even if the output power of the solar power generation device 50 temporarily decreases in this way, the connection point power is controlled to be the first target value by the power storage device 40 performing the load following operation. Furthermore, the power conversion device 52 of the solar power generation device 50 may be equipped with a function corresponding to an output suppression system in which the power company can temporarily stop purchasing energy or a function for suppressing the voltage rise of the power system 2. Using such a function, the solar power generation device 50 may perform an output control operation as the second distributed power source.

[0100] Further, in the present embodiment, the control unit 73 may control the second distributed power source to perform an output control operation in which the power output has an upper limit of a third power value greater than the second power value at a third timing after the first timing. Here, consider a case where the first distributed power source is the power storage device 40 and the solar power generation device 50 also performs a load following operation at the third timing. In this case, when the solar radiation amount temporarily decreases and the generated power of the solar power generation device 50 decreases, the discharge power of the power storage device 40 increases by the amount corresponding to the decrease in the generated power of the solar power generation device 50. When the discharge power of the power storage device 40 increases by the amount corresponding to the decrease in the generated power of the solar power generation device 50, even when the solar radiation amount recovers, the discharge power of the power storage device 40 remains increased and becomes stable. That is, after the solar radiation amount recovers, the generated power of the solar power generation device 50 cannot be effectively utilized. On the other hand, in the present embodiment, by having the solar power generation device 50 perform the output control operation even after the third timing, the generated power of the solar power generation device 50 can be effectively utilized.

[0101] Although the present disclosure has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications or alterations based on the present disclosure. Therefore, it should be noted that these modifications or alterations are included within the scope of the present disclosure. For example, the functions and the like included in each functional unit can be rearranged so as not to be logically inconsistent. A plurality of functional units and the like can be combined into one or divided. Each of the embodiments of the present disclosure described above is not limited to being faithfully implemented in each of the described embodiments, and can be implemented by appropriately combining each feature or omitting a part thereof. That is, those skilled in the art can make various modifications and alterations based on the present disclosure. Therefore, these modifications and alterations are included within the scope of the present disclosure. For example, in each embodiment, each functional unit, each means, or each step and the like can be added to other embodiments so as not to be logically inconsistent, or can be replaced with each functional unit, each means, or each step and the like of other embodiments. Also, in each embodiment, a plurality of each functional unit, each means, or each step and the like can be combined into one or divided. Further, each of the embodiments of the present disclosure described above is not limited to being faithfully implemented in each of the described embodiments, and can also be implemented by appropriately combining each feature or omitting a part thereof.

[0102] For example, in the above-described embodiment, the combinations of the plurality of distributed power sources included in the power management system 1 were described as being different. However, the combinations of the plurality of distributed power sources included in the power management system 1 may be the same. For example, all of the plurality of distributed power sources included in the power management system 1 may be power storage devices 40. In this case, among the plurality of power storage devices 40, the power storage device 40 having the fastest response speed due to a degree of deterioration smaller than that of the other power storage devices 40 may be set as the first distributed power source. Also, among the plurality of power storage devices 40, any power storage device 40 other than the power storage device 40 set as the first distributed power source may be set as the second distributed power source.

[0103] For example, in the above-described embodiment, the power management system 1 as shown in FIG. 1 was described as including the power sensor 10. However, the power management system 1 may include a current sensor between the connection point 3 and the distribution board 20 instead of the power sensor 10. In this case, the control unit 73 of the power management device 70 may receive, via the communication unit 71, the current value detected by the current sensor from the current sensor. The control unit 73 may calculate the connection point power based on the received current value.

[0104] For example, in the above-described embodiment, the power management system 1 as shown in FIG. 1 was described as including one power sensor 10 or a current sensor. However, the power management system 1 may include two or more power sensors 10 or current sensors. In this case, the power management system 1 may include the same number of power sensors 10 or current sensors as the number of distributed power sources included in the power management system 1. In this case, the plurality of distributed power sources and the plurality of power sensors 10 or current sensors may be communicable with each other.

[0105] For example, in the above-described embodiment, the power management device 70 was described as being a HEMS. However, the power management device of the present disclosure is not limited to a HEMS. As another example, the power management device of the present disclosure may be an information processing device of an aggregation coordinator, an information processing device of a resource aggregator, or an AEMS (Area Energy Management System) that constitutes a VPP.

[0106] For example, in the above-described embodiment, the load-following operation has been described as operating while outputting power that follows the load power so that the connection point power becomes the reference value. However, the load-following operation is not limited to operating while outputting power as long as it follows the load power so that the connection point power becomes the reference value. For example, when the first distributed power source is the power storage device 40, the power storage device 40 may follow the load power so that the connection point power becomes the reference value by charging the storage battery 42. That is, the power storage device 40 may perform a load-following operation by charging the storage battery 42. With such a configuration, for example, when the output power of the second distributed power source is greater than the power consumption of the load group 30, the power storage device 40 can perform a load-following operation by charging the storage battery 42 with the surplus of the output power of the second distributed power source.

[0107] In one embodiment, (1) the power management device Before and after the first timing at which the power supplied from the power system or the power flowing reversely to the power system is changed from the first target value to the second target value, among the plurality of distributed power sources electrically connected to the power system, the first distributed power source performs a load-following operation, and the second distributed power source is controlled to perform an operation of outputting power with a predetermined value as an upper limit. The control unit is provided.

[0108] (2) In the power management device according to (1) above, The control unit At the second timing before the first timing, the first distributed power source is controlled to perform a load-following operation with the first target value as a reference value, At the first timing, the first distributed power source may be controlled to perform a load-following operation with the second target value as a reference value.

[0109] (3) In the power management device according to (1) or (2) above, The control unit At a timing before the second timing, the second distributed power source is controlled to perform an operation of outputting power with a first power value as an upper limit, Between the second timing and a third timing after the first timing, control is performed such that the second distributed power source performs an operation of outputting power with a second power value as an upper limit of the predetermined value. The second power value may be smaller than the first power value.

[0110] (4) In the power management device according to any one of (1) to (3) above, The control unit At a third timing after the first timing, control is performed such that the second distributed power source performs an operation of outputting power with a third power value as an upper limit. Between the second timing and the third timing before and after the first timing, control is performed such that the second distributed power source performs an operation of outputting power with a second power value as an upper limit of the predetermined value. The second power value may be smaller than the third power value.

[0111] (5) In the power management device according to any one of (2) to (4) above, The control unit may set the first interval from the second timing to the first timing to be equal to or longer than the settling time when the change value of the output power of the first distributed power source corresponds to the difference between the first power value and the second power value.

[0112] (6) In the power management device according to (4) above, The control unit may set the second interval from the first timing to the third timing to be equal to or longer than the settling time when the change value of the output power of the first distributed power source corresponds to the difference between the first target value and the first target value.

[0113] (7) In the power management device according to any one of (1) to (6) above, The first distributed power source is a power storage device, The second distributed power source may be a solar power generation device.

[0114] (8) In the power management device according to any one of (3) above or (4) to (6) subordinate to (3) above, when the power consumption of the load group electrically connected to the power grid is equal to or greater than a power threshold at a fourth timing after the third timing, the control unit may control the third distributed power source among the plurality of distributed power sources to perform an operation of outputting power with a fourth power value as an upper limit.

[0115] (9) In the power management device according to (8) above, the second distributed power source is a solar power generation device, the third distributed power source may be a fuel cell device.

[0116] (10) In the power management device according to any one of (4) above or (5) to (9) subordinate to (4) above, the second distributed power source is a solar power generation device, the control unit after the third timing, calculates the maximum power value that can be output when the solar power generation device operates in maximum power point tracking (MPPT) control, calculates a differential power value obtained by subtracting the second target value from the power consumption of the load group electrically connected to the power grid, and may set the third power value to be equal to or less than the maximum power value and the differential power value.

[0117] In one embodiment, (11) A power management system includes a plurality of distributed power sources electrically connected to a power grid, and a power management device that controls, among the plurality of distributed power sources, a first distributed power source to perform a load following operation and a second distributed power source to perform an operation of outputting power with a predetermined value as an upper limit before and after a first timing at which the power supplied from the power grid or fed back to the power grid is changed from a first target value to a second target value.

[0118] In the present disclosure, descriptions such as "first" and "second" are identifiers for distinguishing the relevant configurations. The configurations distinguished by the descriptions such as "first" and "second" in the present disclosure can have their numbers in the configuration exchanged. For example, the first distributed power source can have the identifiers "first" and "second" exchanged with the second distributed power source. The exchange of identifiers is performed simultaneously. The configurations are still distinguishable after the exchange of identifiers. The identifiers may be deleted. The configurations with the identifiers deleted are distinguished by symbols. Based only on the descriptions of the identifiers such as "first" and "second" in the present disclosure, the order of the configurations shall not be interpreted or used as the basis for the existence of an identifier with a smaller number.

Explanation of Signs

[0119] 1, 1A, 1B: Power management system, 2: Power grid, 3, 3A, 3B: Connection points, 4: Network, 5, 6, 7: Servers, 10: Power sensor, 20: Distribution board, 30: Load group, 40: Energy storage device, 41: Battery, 42: Power conversion device, 50: Photovoltaic power generation device, 51: Solar cell, 52: Power conversion device, 60: Fuel cell device, 61: Fuel cell, 62: Power conversion device, 70: Power management device, 71: Communication unit, 72: Memory unit, 73: Control unit

Claims

1. Before and after a first timing at which power supplied from a power system or power flowing reversely into the power system is changed from a first target value to a second target value, among a plurality of distributed power sources electrically connected to the power system, a first distributed power source performs load-following operation, and a second distributed power source performs operation of outputting power with a predetermined value as an upper limit. A power management device comprising a control unit that controls the operation.

2. The control unit: At a second timing earlier than the first timing, controls the first distributed power source to perform load-following operation with the first target value as a reference value; At the first timing, controls the first distributed power source to perform load-following operation with the second target value as a reference value. The power management device according to claim 1.

3. The control unit: At a timing earlier than the second timing, controls the second distributed power source to perform operation of outputting power with a first power value as an upper limit; Between the second timing and a third timing later than the first timing before and after the first timing, controls the second distributed power source to perform operation of outputting power with a second power value as an upper limit with the predetermined value; The second power value is smaller than the first power value. The power management device according to claim 2.

4. The control unit: At a third timing later than the first timing, controls the second distributed power source to perform operation of outputting power with a third power value as an upper limit; Between the second timing and the third timing before and after the first timing, controls the second distributed power source to perform operation of outputting power with a second power value as an upper limit with the predetermined value; The second power value is smaller than the third power value. The power management device according to claim 2.

5. The control unit sets a first interval from the second timing to the first timing to be equal to or longer than a setting time when a change value of the output power of the first distributed power source corresponds to a difference between the first power value and the second power value. The power management device according to claim 3.

6. The control unit sets a second interval from the first timing to the third timing to be equal to or longer than a setting time when a change value of the output power of the first distributed power source corresponds to a difference between the first target value and the second target value. The power management device according to claim 4.

7. The first distributed power source is a power storage device. The power management device according to any one of claims 1 to 6, wherein the second distributed power source is a solar power generation device.

8. The control unit controls, at a fourth timing after the third timing, the third distributed power source among the plurality of distributed power sources to perform an operation of outputting power with a fourth power value as an upper limit when the power consumption of a load group electrically connected to the power grid is equal to or greater than a power threshold. The power management device according to claim 3.

9. The second distributed power source is a solar power generation device, The power management device according to claim 8, wherein the third distributed power source is a fuel cell device.

10. The second distributed power source is a solar power generation device, The control unit, after the third timing, calculates a maximum power value that can be output when the solar power generation device operates in maximum power point tracking (MPPT: Maximum Power Point Tracking), calculates a differential power value obtained by subtracting the second target value from the power consumption of a load group electrically connected to the power grid, The power management device according to claim 4, wherein the third power value is set to be equal to or less than the maximum power value and the differential power value.

11. A plurality of distributed power sources electrically connected to a power grid, A power management system including: a power management device that controls, before and after a first timing at which power supplied from the power grid or power fed back to the power grid is changed from a first target value to a second target value, a first distributed power source among the plurality of distributed power sources to perform a load following operation, and a second distributed power source to perform an operation of outputting power with a predetermined value as an upper limit.

Images