JP7844549B2 - Communication equipment and communication methods - Google Patents

Description

This invention relates to a communication device, a distributed power supply, and a communication method.

In recent years, technologies that utilize energy storage devices as distributed power sources (e.g., Virtual Power Plants (VPPs)) have become known in order to maintain the balance of power supply and demand in power grids. In such cases, it is necessary to adjust the frequency of the power grid using reverse power flow supplied from the facility to the power grid (hereinafter referred to as supply and demand adjustment control).

When implementing such supply and demand adjustment control, a technique is known for determining the charging and discharging power of the energy storage device for each service (energy management, supply and demand adjustment control). For example, in supply and demand adjustment control, an upper limit is set for the charging and discharging power of the energy storage device (for example, Patent Document 1).

Japanese Patent Publication No. 2020-137368

Incidentally, possible methods for measuring the reference power used in the control of distributed power sources include measuring the power flow from the power grid to the facility or the reverse power flow from the facility to the power grid (hereinafter referred to as "point-of-reception measurement"), and measuring the discharge power or charging power of distributed power sources (hereinafter referred to as "individual equipment measurement").

However, in the current supply and demand adjustment market, point-of-reception measurements are permitted, but individual equipment measurements are not.

As a result of diligent research, the inventors found that, assuming cases where individual device measurements are also permitted, it is necessary to consider a mechanism for appropriately executing supply and demand adjustment control using distributed power sources.

Therefore, the present invention was made to solve the above-mentioned problems, and aims to provide a communication device, a distributed power source, and a communication method that enable appropriate supply and demand adjustment control using distributed power sources when two or more methods for measuring reference power are anticipated.

One aspect of the disclosure is a communication device comprising: a first communication unit that communicates with a power management server that manages the distributed power sources used in supply and demand adjustment control to maintain the frequency of the power system, and a second communication unit that communicates commands with the distributed power sources, including information elements that specify the type of measurement method for the reference power referenced in the control of the distributed power sources.

One aspect of the disclosure is a distributed power source installed in a facility connected to a power grid, comprising a communication device that communicates with a power management server that manages the distributed power source used in supply and demand adjustment control to maintain the frequency of the power grid, and a communication unit that executes communication of commands including information elements that specify the type of measurement method for the reference power referenced in the control of the distributed power source.

One aspect of the disclosure is a communication method for a distributed power source installed in a facility connected to a power grid, comprising: step A controlling the distributed power source used in supply and demand adjustment control to maintain the frequency of the power grid; and step B communicating a command with the distributed power source that includes an information element specifying the type of measurement method for the reference power referenced in the control of the distributed power source.

According to the present invention, a communication device, a distributed power source, and a communication method are provided that enable appropriate supply and demand adjustment control using distributed power sources when two or more methods for measuring reference power are anticipated.

Figure 1 shows a power management system 1 according to an embodiment of this system. Figure 2 shows a facility 100 according to an embodiment. Figure 3 shows a power storage device 120 according to an embodiment. Figure 4 shows a gateway device 160 according to an embodiment. Figure 5 shows a power management server 200 according to an embodiment. Figure 6 is a diagram illustrating the frequency fluctuation adjustment according to the embodiment. Figure 7 is a diagram illustrating the priority order of distributed power sources according to this embodiment. Figure 8 is a diagram illustrating the priority order of distributed power sources according to the embodiment. Figure 9 is a diagram illustrating the priority order of distributed power sources according to this embodiment. Figure 10 is a diagram illustrating the priority order of distributed power sources according to the embodiment. Figure 11 is a diagram illustrating the priority order of distributed power sources according to the embodiment. Figure 12 is a diagram illustrating the burden ratio according to the embodiment. Figure 13 shows a communication method according to an embodiment of this invention.

The embodiments will be described below with reference to the drawings. In the following drawings, identical or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic.

[Embodiment]
(Power management system)
The power management system according to the embodiment will be described below. The power management system may simply be referred to as a power system.

As shown in Figure 1, the power management system 1 includes a facility 100 and a power management server 200.

Here, facility 100 and power management server 200 are configured to communicate via network 11. Network 11 may include the internet, a dedicated line such as a VPN (Virtual Private Network), or a mobile communication network.

Facility 100 is connected to the power grid 12 and may receive power from or supply power to the power grid 12. Power from the power grid 12 to facility 100 may be referred to as power flow, purchased power, or demanded power. Power from facility 100 to the power grid 12 may be referred to as reverse power flow or sold power. In Figure 1, facilities 100A to 100C are shown as examples of facility 100.

While not particularly limited, facility 100 may be a residential building, a shop, or an office. Facility 100 may also be a multi-unit dwelling containing two or more residences. Facility 100 may also be a mixed-use complex containing at least two of the following types of facilities: residences, shops, and offices. Details of facility 100 will be described later (see Figure 2).

The power management server 200 is managed by a business operator that manages the power related to the power grid 12. This business operator may be a power generation company, a transmission and distribution company, or a retail company. The business operator may be a resource aggregator (RA), or an aggregation coordinator (AC) that manages the RA. The RA may be a business operator that adjusts the power supply and demand balance of the power grid 12. Adjusting the power supply and demand balance may include transactions (negawatt transactions) that exchange reduced power (power flow) from the facility 100 for value. Adjusting the power supply and demand balance may also include transactions that exchange increased power (reverse power flow) for value. In a Virtual Power Plant (VPP), the RA may be a power generation company, a transmission and distribution company, or a retail company.

In this embodiment, communication between the power management server 200 and the gateway device 160 is performed according to a first protocol. On the other hand, communication between the gateway device 160 and the distributed power sources (solar cell device 110, energy storage device 120, or fuel cell device 130) is performed according to a second protocol different from the first protocol. For example, the first protocol can be a protocol compliant with Open ADR (Automated Demand Response) or a proprietary dedicated protocol. For example, the second protocol can be a protocol compliant with ECHONET Lite®, SEP (Smart Energy Profile) 2.0, KNX, or a proprietary dedicated protocol. Note that the first and second protocols only need to be different; for example, both can be proprietary protocols, as long as they are created using different rules. However, the first and second protocols may be protocols created using the same rules.

(facility)
The facility according to the embodiment will be described below. As shown in Figure 2, the facility 100 includes a solar cell device 110, an energy storage device 120, a fuel cell device 130, a load device 140, and a gateway device 160. The facility 100 may also include at least one of the measuring devices 190A and 190B.

The solar cell system 110 is a distributed power source that generates electricity in response to light such as sunlight. For example, the solar cell system 110 consists of a PCS (Power Conditioning System) and solar panels. Here, "installation" may refer to the connection of the solar cell system 110 to the power grid 12.

The energy storage device 120 is a distributed power source that charges and discharges electricity. For example, the energy storage device 120 is composed of a power conditioning system (PCS) and energy storage cells. Here, "installation" may refer to the connection of the energy storage device 120 to the power grid 12.

In this embodiment, the energy storage device 120 is a distributed power source installed in a facility 100 connected to the power grid 12, and is an example of a distributed power source used to maintain the frequency of the power grid 12.

The fuel cell system 130 is a distributed power source that generates electricity using fuel. For example, the fuel cell system 130 consists of a power conditioning system (PCS) and fuel cell cells. Here, "installation" may refer to the connection of the fuel cell system 130 to the power grid 12.

For example, the fuel cell device 130 may be 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).

The load device 140 is a device that consumes power. For example, the load device 140 may include an air conditioning system that adjusts the temperature of a predetermined space in the facility 100, or a lighting system that adjusts the illuminance of a predetermined space in the facility 100. The load device 140 may also include video equipment, audio equipment, a refrigerator, a washing machine, a personal computer, and the like.

The gateway device 160 communicates with the power management server 200 and the energy storage device 120. The gateway device 160 may also be referred to as a VPP controller. The gateway device 160 may have the function of managing the power related to the facility 100. The gateway device 160 may also have the function of controlling the solar cell device 110, the energy storage device 120, the fuel cell device 130, and the load equipment 140. In such cases, the gateway device 160 may be referred to as an EMS (Energy Management System), a LEMS (Local EMS), or a HEMS (Home EMS).

The measuring device 190A measures at least one of the power flow from the power system 12 to facility 100 and the reverse power flow from facility 100 to the power system 12. For example, the measuring device 190A may be a Smart Meter belonging to the power company. The measuring device 190A may transmit information elements indicating the measurement results (integral value of power flow or reverse power flow) for each first interval (e.g., 30 minutes) to the gateway device 160. The measuring device 190A may also transmit information elements indicating the measurement results for a second interval shorter than the first interval (e.g., 1 minute) to the gateway device 160.

The measuring device 190B measures at least one of the power output (discharged) from the energy storage device 120 and the power input (charged) to the energy storage device 120. For example, the measuring device 190B may be a CT (Current Transformer). The measuring device 190B may also be a measuring device certified by a third party.

(Energy storage device)
The following describes an embodiment of the energy storage device. As shown in Figure 3, the energy storage device 120 includes a BT121, a monitoring unit 122, a communication unit 123, and a control unit 124. Although not shown in Figure 3, the energy storage device 120 may also include a PCS.

BT121 is a storage cell in the energy storage device 120.

The monitoring unit 122 monitors the frequency of the power system 12. For example, the monitoring unit 122 is connected to a measuring device installed between the power system 12 and the energy storage device 120, and monitors the frequency of the power measured by the measuring device. The measuring device may be the measuring device 190A described above, or it may be the measuring device 190B described above. The measuring device may be installed in the same location as the measuring device 190A described above.

The communication unit 123 is comprised of a communication module. The communication module may be a wireless communication module compliant with standards such as IEEE 802.11a/b/g/n/ac/ax, ZigBee, Wi-SUN, LTE, 5G, or 6G, or it may be a wired communication module compliant with standards such as IEEE 802.3 or a proprietary protocol.

In this embodiment, the communication unit 123 is configured to communicate commands with the gateway device 160 that include an information element specifying the type of measurement method for the reference power referenced in the control of the energy storage device 120. The communication unit 123 may also communicate commands with the gateway device 160 that include an information element specifying the target power used in the control of the energy storage device 120.

The control unit 124 may include at least one processor. At least one processor may consist of a single integrated circuit (IC), or it may consist of multiple communicatively connected circuits (such as integrated circuits and/or discrete circuits).

The control unit 124 controls BT121. In this embodiment, the control unit 124 may control the charging or discharging of the energy storage device 120 in supply and demand adjustment control for maintaining the frequency of the power system 12. The control unit 124 may also control the charging or discharging of the energy storage device 120 in control other than supply and demand adjustment control (hereinafter referred to as energy management control).

Firstly, the supply and demand adjustment control may include a first control that controls the energy storage device 120 (BT121) within the facility 100. The first control may autonomously perform charging and discharging of the energy storage device 120 (BT121) based on the frequency of the power system 12 monitored by the monitoring unit 122. The first control may also be a short-period control (e.g., GF) as described later. The frequency adjustment power of the power system 12 by the first control may be referred to as the primary adjustment power.

Secondly, the supply and demand adjustment control may include a second control that controls the energy storage device 120 (BT121) from outside the facility 100. The second control may be a control that directly performs charging and discharging of the energy storage device 120 (BT121) by the power management server 200. The second control may also be a medium-cycle control (e.g., LFC) as described later. The frequency adjustment capability of the power system 12 by the second control may be referred to as secondary adjustment capability.

Energy management control may also be control related to the management of the power demand of the facility 100 where the energy storage device 120 is installed. Energy management control may also be control that reduces the error between the planned power demand of the facility 100 and the actual power demand. Energy management control may also be referred to as energy management control.

While not particularly limited, the error in the planned power demand may be the error between the planned power demand and the actual power demand, or the error between the planned power demand and the predicted power demand. The predicted power demand may be a value predicted at a later time than when the planned power demand is formulated.

For example, the period during which supply and demand adjustment control may be applied may be defined as the target period (e.g., one day). In such a case, the planned value of power demand may include plans formulated at a time prior to the target period (e.g., 12:00 the day before the target period). The forecast value of power demand may include values forecast at a time prior to a unit period included in the target period (e.g., a 30-minute period) (e.g., one hour before the unit period).

In this embodiment, the control unit 124 controls at least one of the discharge power and charge power of the BT121 in supply and demand adjustment control (e.g., LFC described later) and energy management control, so that the power measured by the measurement method specified by the gateway device 160 approaches the target power specified by the gateway device 160.

(Gateway device)
The gateway device according to the embodiment will be described below. As shown in Figure 4, the gateway device 160 has a first communication unit 161, a second communication unit 162, and a control unit 163. In this embodiment, the gateway device 160 is an example of a communication device.

The first communication unit 161 is composed of a communication module. The communication module may be a wireless communication module compliant with standards such as IEEE 802.11a/b/g/n/ac/ax, ZigBee, Wi-SUN, LTE, 5G, or 6G, or it may be a wired communication module compliant with standards such as IEEE 802.3 or a proprietary protocol.

In this embodiment, the first communication unit 161 constitutes a first communication unit that communicates with the power management server 200 via the network 11. The power management server 200 manages the distributed power sources (in this embodiment, the energy storage device 120) used to maintain the frequency of the power system 12.

The second communication unit 162 is composed of a communication module. The communication module may be a wireless communication module compliant with standards such as IEEE 802.11a/b/g/n/ac/ax, ZigBee, Wi-SUN, LTE, 5G, or 6G, or it may be a wired communication module compliant with standards such as IEEE 802.3 or a proprietary protocol.

The second communication unit 162 may communicate with the solar cell device 110, the energy storage device 120, and the fuel cell device 130. Although the signal lines are omitted in Figure 2, the second communication unit 162 may also communicate with the load device 140, and with the measuring devices 190A and 190B.

In this embodiment, the second communication unit 162 constitutes a second communication unit that communicates with a distributed power source (in this embodiment, a power storage device 120) used to maintain the frequency of the power system 12.

Firstly, the second communication unit 162 communicates with the energy storage device 120 a command (hereinafter referred to as the first command) containing an information element specifying the type of measurement method for the reference power referenced in the control of the energy storage device 120. The first command may include a command to set information in the energy storage device 120 (SET command), or a command to request information from the energy storage device 120 (GET command).

The control of the energy storage device 120 may include supply and demand adjustment control and energy management control. The supply and demand adjustment control may include a first control (e.g., GF) and a second control (e.g., LFC).

The method for measuring the reference power may include a first method for measuring at least one of the power supplied from the power system 12 to the facility 100 (power flow power) and the power supplied from the facility 100 to the power system 12 (reverse power flow power). The first method may be a method of measuring power using measuring device 190A, or a method of measuring power using measuring device installed in the same location as measuring device 190A. Hereinafter, the first method may be referred to as power receiving point measurement.

The method for measuring the reference power may include a second method for measuring at least one of the power output (discharged) from the energy storage device 120 (discharged power) and the power input (charged) to the energy storage device 120 (charged power). The second method may be a method of measuring power using the measuring device 190B. Hereinafter, the second method may be referred to as individual device measurement.

In other words, the reference power is at least one of either the power flow or the reverse power flow when the first method is specified, and at least one of either the discharge power or the charge power when the second method is specified.

Here, the measurement method for the reference power used in supply and demand adjustment control may differ from the measurement method for the reference power used in energy management control.

Secondly, the second communication unit 162 communicates with the energy storage device 120 a command (hereinafter referred to as the second command) containing an information element that specifies the target power used for controlling the energy storage device 120. The second command may include a command to set information on the energy storage device 120 (SET command), or a command to request information from the energy storage device 120 (GET command).

The target power is, if the first method is specified, at least one of the target powers of current power and reverse current power; and if the second method is specified, at least one of the target powers of discharge power and charge power.

Thus, the combination of the first and second commands determines the type of measurement method for the reference power and the target power of the power measured by the specified measurement method.

Here, we have illustrated a case where the first and second commands are separate commands, but the first and second commands may be combined into a single third command. That is, the third command may be a command specifying the target power for power measured by the first method or a command specifying the target power for power measured by the second method. Even in such a case, the third command is considered to be a command containing an information element specifying the type of measurement method for the reference power referenced in the control of the energy storage device 120.

The control unit 163 controls the gateway device 160. The control unit 163 may include at least one processor. At least one processor may consist of a single integrated circuit (IC) or multiple communicatively connected circuits (such as integrated circuits and/or discrete circuits).

The control unit 163 may control the solar cell device 110, the energy storage device 120, and the fuel cell device 130. The control unit 163 may also control the load equipment 140. For example, the control unit 163 may control the charging and discharging of the energy storage device 120 based on control commands received from the power management server 200. Control commands related to a second control (e.g., LFC), which is one type of supply and demand adjustment control, may be received from the power management server 200 for the purpose of maintaining the frequency of the power grid 12. Control commands related to energy management control may be received from the power management server 200 in accordance with a charge/discharge plan formulated for the purpose of energy management of the facility 100. The control commands may include target power for the discharge power or charge power of the energy storage device 120.

(Power management server)
The following describes a power management server according to an embodiment. As shown in Figure 5, the power management server 200 includes a communication unit 210, a management unit 220, and a control unit 230.

The communication unit 210 is comprised of a communication module. The communication module may be a wireless communication module compliant with standards such as IEEE 802.11a/b/g/n/ac/ax, ZigBee, Wi-SUN, LTE, 5G, or 6G, or it may be a wired communication module compliant with standards such as IEEE 802.3.

For example, the communication unit 210 may communicate with the facility 100 (energy storage device 120 or gateway device 160).

Firstly, the communication unit 210 may receive information from facility 100 indicating the behavior of facility 100 regarding supply and demand adjustment control (hereinafter referred to as "first behavior information"). The first behavior information may include information indicating whether or not facility 100 wishes to participate in supply and demand adjustment control, and may also include information indicating whether or not facility 100 actively wishes to contribute to supply and demand adjustment control.

Secondly, the communication unit 210 may receive information from the facility 100 indicating the behavior of the facility 100 regarding energy management control (hereinafter referred to as "second behavior information"). The second behavior information may include information indicating whether the energy storage device 120 performs energy management control while ensuring the available supply amount for supply and demand adjustment control; information indicating whether the energy management control is performed as determined by the planned value of the facility 100's demand power; and information indicating whether the energy management control is performed in a manner that reduces the error in the planned value of the facility 100's demand power.

The management unit 220 is composed of storage media such as HDDs (Hard Disk Drives), SSDs (Solid State Drives), and non-volatile memory.

The management unit 220 manages information related to facility 100. For example, information related to facility 100 includes the type of distributed power source (solar cell system 110, energy storage system 120, or fuel cell system 130) installed in facility 100, and the specifications of the distributed power source (solar cell system 110, energy storage system 120, or fuel cell system 130) installed in facility 100. The specifications may include the rated power generation of the solar cell system 110, the rated charging power of the energy storage system 120, the rated discharge power of the energy storage system 120, and the rated output power of the fuel cell system 130. The specifications may also include the rated capacity and maximum charge/discharge power of the energy storage system 120.

The control unit 230 may include at least one processor. At least one processor may consist of a single integrated circuit (IC), or it may consist of multiple communicatively connected circuits (such as integrated circuits and/or discrete circuits).

For example, the control unit 230 may identify the target distributed power sources to be used in supply and demand adjustment control for maintaining the frequency of the power system 12. The control unit 230 determines the priority order of the distributed power sources identified as target distributed power sources based on at least one of the first priority of distributed power sources related to supply and demand adjustment control and the second priority of distributed power sources related to energy management control other than supply and demand adjustment control. Details of the priority order of distributed power sources will be described later.

(Frequency fluctuation adjustment)
The frequency fluctuation adjustment of the power system 12 according to this embodiment will be described below.

As shown in Figure 6, the control for adjusting frequency fluctuations differs depending on the fluctuation period of the system being adjusted. Specifically, the control for adjusting frequency fluctuations includes short-period control (e.g., several tens of seconds to several minutes), medium-period control (e.g., several minutes to several tens of minutes), and long-period control (e.g., several tens of minutes to several hours).

Here, short-period control may also be referred to as GF (Governor Free). Short-period control is a control method used to eliminate supply and demand fluctuations that cannot be tracked by medium-period control. For example, such supply and demand fluctuations could include the shutdown of a regulating power supply operating under short-period control.

Medium-cycle control may also be called LFC (Load Frequency Control) or AFC (Automatic Frequency Control). Medium-cycle control is a control method designed to mitigate supply and demand fluctuations that are difficult to predict.

Long-period control may also be called DPC (Dispatching Power Control) or EDC (Economic Load Dispatching Control). Long-period control is a control method designed to mitigate supply and demand fluctuations based on supply and demand forecasts.

While not particularly limited, the supply and demand adjustment control in which the energy storage device 120 autonomously controls charging and discharging based on the frequency of the power system 12 may be applied to the short-period control (e.g., GF) described above.

(Supply and demand adjustment control and energy management control)
Given the background described above, we will consider a case that takes into account both supply and demand adjustment control and energy management control. In the following, we will mainly explain the case in which the distributed power source used for supply and demand adjustment control and energy management control is the energy storage device 120. Therefore, the target distributed power source may also be referred to as the target energy storage device 120.

In such a case, assuming that energy storage devices 120 wishing to participate in the first control (e.g., GF), which is one of the supply and demand adjustment control methods, uniformly execute the first control, the following problems arise.

Firstly, the energy storage device 120 must always maintain a supplyable amount of power to accommodate the first control. Therefore, in practice, the supplyable amount must be maintained even during periods when the first control is not required, and in energy management control, only the remaining power obtained by subtracting the supplyable power from the rated power of the energy storage device 120 can be used. For example, assuming that frequency fluctuations remain within ±0.2 Hz for more than 99% of the period during which the first control may be applied, and assuming a 5% adjustment rate, only about 8% of the supplyable amount is used for the first control. In other words, even though there is room to use the supplyable amount in energy management control, the supplyable amount is always maintained, preventing effective utilization of the energy storage device 120.

Secondly, a method could be considered in which the power management server 200 dynamically controls the energy storage device 120 to efficiently execute the first control and energy management control. However, in the first control, it is required to measure the charging and discharging power of the energy storage device 120 at a granularity of 0.3% of the available power, so the load on the power management server 200 to acquire the charging and discharging power of the energy storage device 120 at a granularity of 0.3% is extremely large. Therefore, it is better to pre-select the target energy storage device 120 and leave the operation of the first control itself to the autonomous operation of the target energy storage device 120.

In this embodiment, to solve the above-mentioned problems, the power management server 200 pre-identifies the target energy storage device 120 to be used for the first control from among the energy storage devices 120 installed in each of the two or more facilities 100.

(Priority of distributed power sources)
The following describes the priority order of the energy storage devices 120 according to the embodiment. Since the target energy storage devices 120 are identified by the power management server 200, the operation of the control unit 230 of the power management server 200 will be described primarily.

Firstly, the control unit 230 may identify the first priority of the energy storage device 120 based on the first behavior information described above.

The first priority may be defined by an element indicating whether or not the device actively desires to contribute to the first control. For example, the first priority of a storage device 120 that actively desires to contribute to the first control may be higher than the first priority of a storage device 120 that does not actively desire to contribute to the first control (hereinafter, judgment criterion 1-A).

Secondly, the control unit 230 may determine the second priority of the energy storage device 120 based on the second behavior information described above.

The second priority may be defined by an element indicating whether or not the energy storage device 120 performs energy management control while ensuring a supplyable amount (i.e., charge/dischargeable amount) that it can provide for the first control. The second priority of an energy storage device 120 that performs energy management control while ensuring a supplyable amount for the first control may be higher than the second priority of an energy storage device 120 that performs energy management control without ensuring a supplyable amount for the first control (hereinafter, judgment criterion 2-A).

The second priority may be defined by an element indicating whether or not energy management control is performed as determined by the planned power demand of facility 100. The second priority of a storage device 120 that performs energy management control as determined by the planned power demand of facility 100 may be higher than the second priority of a storage device 120 that does not perform energy management control as determined by the planned power demand of facility 100 (hereinafter, judgment criterion 2-B).

The second priority may be defined by an element indicating whether or not energy management control is performed to reduce the error in the planned value of facility 100's power demand. The second priority of a storage device 120 that does not perform energy management control to reduce the error in the planned value of facility 100's power demand may be higher than the second priority of a storage device 120 that does perform energy management control to reduce the error in the planned value of facility 100's power demand (hereinafter, judgment criterion 2-C).

Furthermore, the second priority may be defined by a combination of the judgment criteria 2A to 2C described above. For example, the second priority of a storage device 120 that performs energy management control as determined by the planned value of the facility 100's power demand may be higher than the second priority of a storage device 120 that performs energy management control while ensuring the available supply for the first control (hereinafter, judgment criterion 2-D). The second priority of a storage device 120 that performs energy management control while ensuring the available supply for the first control may be higher than the second priority of a storage device 120 that performs energy management control to reduce the error in the planned value of the facility 100's power demand (hereinafter, judgment criterion 2-E).

Here, the first and second priorities are priorities for determining the priority of the energy storage devices 120 identified as the target energy storage devices 120 used for the first control. Therefore, it should be noted that the second priority is the priority of the energy storage devices 120 used for the first control, not the priority of the energy storage devices 120 used for energy management control. The priority of the energy storage devices 120 used for energy management control can be considered to be the reverse priority of the energy storage devices 120 used for the first control (i.e., the second priority).

Thirdly, the control unit 230 determines the priority of the energy storage device 120 based on at least one of the first priority and second priority criteria. That is, the control unit 230 determines the priority of the energy storage device 120 based on one or more criteria selected from criteria 1-A and criteria 2A to 2E.

Here, the control unit 230 may identify the target energy storage devices 120 from among the energy storage devices 120 that wish to participate in the first control. The control unit 230 may also identify the target energy storage devices 120 for each frequency fluctuation range of the power system 12 for which the first control is required. The target energy storage devices 120 for each fluctuation range may be identified based on the priority of the energy storage devices 120 (i.e., at least one of the first priority and second priority).

For example, consider a case where the total available power output of the energy storage device 120 managed by the power management server 200 is ±1000kW, the frequency of the power system 12 is 50Hz, and the adjustment ratio is 5%, as shown in Figure 7. In such a case, when the frequency fluctuation is 2.5Hz, the energy storage device 120 managed by the power management server 200 is required to discharge 1000kW of power. While not particularly limited, a dead zone may exist within a predetermined range (-0.01 to +0.01Hz).

Here, the control unit 230 identifies energy storage device #A as the target energy storage device 120 to be used in the fluctuation range of -0.2Hz or less and -0.2 to 1.25Hz, energy storage device #B as the target energy storage device 120 to be used in the fluctuation range of -0.2Hz or less and 1.25 to 2.0Hz, and energy storage device #C as the target energy storage device 120 to be used in the fluctuation range of -0.2Hz or less and 2.0 to 2.5Hz. In terms of priority used in the first control, the priority of energy storage device #A is higher than the priority of energy storage device #B, and the priority of energy storage device #B is higher than the priority of energy storage device #C. Each of energy storage devices #A to #C only needs to include at least one target energy storage device 120. Energy storage devices #A to #C can also be considered as groups #A to #C.

Under these premises, the control unit 230 identifies the target energy storage devices 120 belonging to each of the groups #A to #C based on the first and second priorities. For example, the control unit 230 may identify as the target energy storage device 120 belonging to group #A a device that actively desires to contribute to the first control and performs energy management control as determined by the planned value of the facility 100's power demand. The control unit 230 may identify as the target energy storage device 120 belonging to group #B a device that actively desires to contribute to the first control and performs energy management control while ensuring the available supply for the first control. The control unit 230 may identify as the target energy storage device 120 belonging to group #C a device that does not actively desire to contribute to the first control and performs energy management control to reduce the error in the planned value of the facility 100's power demand.

For example, in the case where the available capacity of the target energy storage device 120 belonging to group #A is ±500kW, as shown in Figure 8, the target energy storage device 120 belonging to group #A will perform the first control within the fluctuation range of -0.2 or less and -0.2 to 1.25Hz. It should be noted that in such a case, the adjustment rate (+ side) applied to the target energy storage device 120 belonging to group #A needs to be changed from 5% to 2.5%.

For example, in the case where the available capacity of the target energy storage device 120 belonging to group #B is ±300kW, as shown in Figure 9, the target energy storage device 120 belonging to group #B will perform the first control within the fluctuation range of -0.2 or less and 1.25 to 2.0Hz. In such a case, it should be noted that the adjustment rate (+ side) applied to the target energy storage device 120 belonging to group #B should be changed from 5% to 4%, and 0 to 1.25Hz should be set as a dead zone.

For example, in the case where the available capacity of the target energy storage device 120 belonging to group #C is ±200kW, as shown in Figure 10, the target energy storage device 120 belonging to group #C will perform the first control within the fluctuation range of -0.2 or less and 2.0 to 2.5. In such a case, it should be noted that the adjustment rate (+ side) applied to the target energy storage device 120 belonging to group #C must remain unchanged at 5%, and the dead zone must be set to 0 to 2.0 Hz.

In the examples shown in Figures 8 to 10, within the fluctuation range of -0.2 to 0 Hz, only the target energy storage devices 120 belonging to group #A perform the first control, while the target energy storage devices 120 belonging to groups #B and #C do not need to perform the first control.

Here, we will focus on the fluctuation range of -0.2 to 0 Hz and explain the behavior of the target energy storage devices 120 belonging to groups #A to #C. Here, the reference value is the charge/discharge amount of the energy storage device 120 used to calculate the available energy supply, and the actual value is the charge/discharge amount of the energy storage device 120 obtained as a result of the first control or energy management control.

As shown in Figure 11, the target energy storage device 120 belonging to group #A performs first control based on a reference value, so the actual value may fluctuate based on the reference value in order to maintain the frequency of the power system 12. On the other hand, the target energy storage devices 120 belonging to groups #B and #C have room to perform energy management control, and the actual value may deviate from the reference value due to energy management control. In other words, the target energy storage devices 120 belonging to groups #B and #C can be effectively utilized for energy management control. In Figure 11, an example is shown where the frequency deviation is within the dead zone (e.g., -0.1 to 1.0 Hz) before time t, and the frequency deviation falls below -0.2 Hz after time t.

Here, the charging and discharging switching frequency required by the energy management control may be lower than the charging and discharging switching frequency required by the first control. In this configuration, degradation of the target energy storage devices 120 belonging to group #A is unavoidable, but degradation of the target energy storage devices 120 belonging to groups #B and #C can be suppressed.

(burden rate)
The load factor according to the embodiment will be described below. As described above, in the first control (for example, GF), which is one of the supply and demand adjustment controls, the power (discharge power or charge power) of the energy storage device 120 with respect to the frequency deviation of the power system 12 differs for each group. In order to realize such control, a load factor for each group may be introduced in order to define the power (discharge power or charge power) of the energy storage device 120 with respect to the frequency deviation of the power system 12 for each group. The load factor is a value used to convert the adjustment rate to a value for each group. The load factor may also be read as a load function for each group that defines the load factor. Specifically, the control will be described with reference to Figure 12.

Firstly, as shown on the left side of Figure 12, the power management server 200 transmits a common adjustment rate for two or more facilities 100 (energy storage devices 120) to the gateway device 160. Each gateway device 160 transmits a command to the energy storage device 120 containing information elements specifying the adjustment rate received from the power management server 200. The adjustment rate may be expressed as a function of the control command (control function) for the frequency deviation of the power system 12.

Secondly, as shown in the center of Figure 12, the gateway device 160 transmits a command to the energy storage device 120 containing an information element that specifies a burden function individually defined for the facility 100 (energy storage device 120). The control command may also be a command transmitted from the power management server 200 to the gateway device 160. The output command may be considered to be at least one of the power actually output (discharged) from the energy storage device 120 and the power actually input (discharged) into the energy storage device 120.

Here, the burden function may be received from the power management server 200 or pre-configured in the gateway device 160. The burden function may be expressed as a function of the control command (x-axis) and the output command (y-axis). The burden function may also be specified by an information element that specifies the coordinates of at least two points in the coordinate space defined by the x-axis and y-axis. For example, as shown in Figure 12, the burden function may be specified by two coordinates, (x1, y1) and (x5, y5), as in the burden function of group #A. The burden function may also be specified by four coordinates, (x1, y1), (x2, y2), (x4, y4), and (x5, y5), as in the burden functions of group #B and group #C.

As a result, as shown on the right side of Figure 12 (control image), the energy storage device 120 can implement the control described in Figures 8 to 10 using a burden function.

Here, we have described the case where a burden function is applied to the first control (e.g., GF), but the burden function may also be applied to the second control (e.g., LFC). The burden function applied to the second control may be the same as the burden function applied to the first control, or it may be set separately from the burden function applied to the first control. For example, in the second control, the target power used for controlling the energy storage device 120 may be the power in which the burden function is reflected in the target power included in the control command.

(Communication method)
The communication method according to the embodiment will be described below.

First, we will explain energy management control.

As shown in Figure 13, in step S10, the power management server 200 transmits a control command related to energy management control to the gateway device 160. The control command may include an information element specifying the target power used in energy management control.

In step S11A, the gateway device 160 transmits a first command (SET command) to the energy storage device 120, which includes an information element specifying the type of measurement method for the reference power referenced in the energy management control. The gateway device 160 then transmits a second command (SET command) to the energy storage device 120, which includes an information element specifying the target power used in the energy management control. As described above, the first and second commands may be combined into a single third command. The target power used in the energy management control may be referred to as the AC energy management charge/discharge target value.

In step S11B, the gateway device 160 receives a response command (SET response) to the SET command from the energy storage device 120.

Through the processing in steps S11A and S11B, the measurement method for the reference power and the target power are set in the energy storage device 120.

In step S12, the energy storage device 120 performs energy management control. Specifically, the energy storage device 120 measures power according to the reference power measurement method specified in step S11, and controls at least one of the discharge power and charge power of the energy storage device 120 (BT121) to bring the measured power closer to the target power.

In step S13A, the gateway device 160 transmits a first command (GET command) to the energy storage device 120, which includes an information element specifying the type of measurement method for the reference power referenced in the energy management control. The gateway device 160 then transmits a second command (GET command) to the energy storage device 120, which includes an information element specifying the target power used in the energy management control. As described above, the first and second commands may be combined into a single third command.

In step S13B, the gateway device 160 receives a response command (GET response) to the GET command from the energy storage device 120. The GET response includes an information element specifying the type of measurement method for the reference power set in the energy storage device 120. The GET response also includes an information element specifying the target power set in the energy storage device 120.

Furthermore, if the gateway device 160 does not need to confirm the type of measurement method for the reference power and the target power, steps S13A and S13B may be omitted.

Secondly, we will explain the second type of supply and demand adjustment control, which is, for example, LFC (Low Force Factor Control).

As shown in Figure 13, in step S20, the power management server 200 transmits a control command for the second control to the gateway device 160. The control command may include an information element specifying the target power to be used in the second control.

In step S21A, the gateway device 160 transmits a first command (SET command) to the energy storage device 120, which includes an information element specifying the type of measurement method for the reference power referenced in the second control. The gateway device 160 then transmits a second command (SET command) to the energy storage device 120, which includes an information element specifying the target power to be used in the second control. As described above, the first and second commands may be combined into a single third command. The target power used in the second control may be referred to as the AC charge/discharge power command value.

In step S21B, the gateway device 160 receives a response command (SET response) to the SET command from the energy storage device 120.

Through the processing in steps S21A and S21B, the measurement method for the reference power and the target power are set in the energy storage device 120.

In step S22, the energy storage device 120 performs a second control. Specifically, the energy storage device 120 measures the power according to the reference power measurement method specified in step S21, and controls at least one of the discharge power and charge power of the energy storage device 120 (BT121) to bring the measured power closer to the target power.

In step S23A, the gateway device 160 transmits a first command (GET command) to the energy storage device 120, which includes an information element specifying the type of measurement method for the reference power referenced in the second control. The gateway device 160 then transmits a second command (GET command) to the energy storage device 120, which includes an information element specifying the target power to be used in the second control. As described above, the first and second commands may be combined into a single third command.

In step S23B, the gateway device 160 receives a response command (GET response) to the GET command from the energy storage device 120. The GET response includes an information element specifying the type of measurement method for the reference power set in the energy storage device 120. The GET response also includes an information element specifying the target power set in the energy storage device 120.

Furthermore, if the gateway device 160 does not need to confirm the type of measurement method for the reference power and the target power, steps S23A and S23B may be omitted.

Here, the measurement method for the reference power referenced in supply and demand adjustment control may differ from the measurement method for the reference power referenced in energy management control.

(Mechanism of action and effects)
In this embodiment, the gateway device 160 transmits a first command (or third command) to the energy storage device 120 that includes an information element specifying the type of reference power measurement method referenced in the control of the energy storage device 120. With this configuration, even when two or more reference power measurement methods are anticipated, such as point-of-reception measurement and individual equipment measurement, supply and demand adjustment control using the energy storage device 120 can be appropriately performed.

For example, by applying individual equipment measurements in supply and demand adjustment control, and applying power receiving point measurements in energy management control during periods when supply and demand adjustment control is not in operation, it is possible to appropriately execute both supply and demand adjustment control and energy management control. In other words, by using different measurement methods for the reference power between supply and demand adjustment control and energy management control, both can be appropriately executed.

While not particularly limited, during periods when supply and demand adjustment control is implemented, individual equipment measurement may be applied to energy management control in the same way as to supply and demand adjustment control.

[Example of change 1]
The following describes a modified example of the embodiment 1. The following primarily describes the differences from the embodiment described above.

In Modification Example 1, the gateway device 160 transmits a command (which may be called the fourth command) containing an information element specifying a threshold for the frequency deviation of the power system 12 to the energy storage device 120. The first control (e.g., GF), which is one of the supply and demand adjustment controls, includes a control that increases the output (discharge power) of the energy storage device 120 to a specific power when the frequency deviation of the power system 12 is below the threshold. The specific power may be the maximum discharge power of the energy storage device 120, or it may be a predetermined power.

Here, the case where the frequency deviation of power system 12 is below the threshold can be considered as a case where an abnormality has occurred in power system 12. Therefore, the threshold may be called the abnormality detection threshold. The unit of the abnormality detection threshold may be expressed in Hz. For example, using Figures 8 to 10 as an example, the abnormality detection threshold is -0.2 Hz.

Here, the abnormality detection threshold may be a value with hysteresis. For example, the abnormality detection threshold may include a first threshold referenced when the frequency deviation of the power system 12 transitions toward a smaller value, and a second threshold referenced when the frequency deviation of the power system 12 transitions toward a larger value. The second threshold is greater than the first threshold. That is, when the frequency deviation of the power system 12 falls below the first threshold, the energy storage device 120 increases its discharge power to a specific power level. When the frequency deviation of the power system 12 exceeds the second threshold, the energy storage device 120 returns its discharge power to the power level before it was increased to the specific power level.

Even in cases where the frequency deviation of the power system 12 changes near the abnormality detection threshold, the fact that the abnormality detection threshold has hysteresis prevents the discharge power of all energy storage devices 120 from frequently increasing or decreasing.

If the frequency deviation of power system 12 is below the anomaly detection threshold (first threshold), the burden function described above does not need to be applied.

[Example of change 2]
The following describes a modified example of the embodiment 2. The following primarily describes the differences from the embodiment described above.

In this embodiment, the gateway device 160 transmits a command (which may be called a fifth command) to the energy storage device 120 that includes information elements specifying a control function (regulating rate) common to two or more facilities 100 (energy storage devices 120) and a burden function individually defined for each facility 100 (energy storage device 120). That is, the power (discharge power or charge power) of the energy storage device 120 is controlled by the control function and the burden function.

In modification example 2, the gateway device 160 transmits an information element to the energy storage device 120 that specifies a function (hereinafter referred to as an individual function) in which the burden function is reflected in the control function. The individual function may also be a function that represents the relationship between frequency deviation and output. That is, the individual function may also be a function that represents the control image shown on the right side of Figure 12.

With this configuration, the computational load on the energy storage device 120 is reduced, and the amount of communication between the gateway device 160 and the energy storage device 120 is also suppressed.

[Other Embodiments]
Although the present invention has been described by the embodiments described above, the descriptions and drawings that constitute part of this disclosure should not be understood as limiting the invention. Various alternative embodiments, examples, and operational techniques will become apparent to those skilled in the art from this disclosure.

The disclosure described above exemplifies a case where the distributed power source used to maintain the frequency of the power grid 12 (the distributed power source used for supply and demand adjustment control) is an energy storage device 120. However, the disclosure is not limited to this. The distributed power source used for supply and demand adjustment control can be any distributed power source capable of adjusting output power, such as a fuel cell device 130.

Although not specifically mentioned in the disclosure above, if the distributed power source used to maintain the frequency of the power system 12 (a distributed power source used for supply and demand adjustment control) is the energy storage device 120, then the power or output of the energy storage device 120 may be appropriately interpreted as discharge or charge. That is, the negative power or negative output of the energy storage device 120 may be considered as charge.

The disclosure described above illustrates a case in which the first control is performed autonomously by the energy storage device 120. However, the disclosure is not limited thereto. The first control may be performed autonomously within the facility 100, or it may be performed autonomously under the control of the gateway device 160.

The disclosure described above illustrates a case where the gateway device 160 is installed at facility 100. However, the disclosure is not limited to this. The gateway device 160 may also be provided by a cloud service implemented by a server or the like on network 11.

Although not specifically mentioned in the disclosure above, when the first method (power receiving point measurement) is applied in energy management control, load-following control by the energy storage device 120 can be achieved by setting the target power of the facility 100's demand to zero.

Although not specifically mentioned in the disclosure above, when the second method (individual device measurement) is applied in supply and demand adjustment control, the contribution to maintaining the frequency of the power system 12 can be easily identified without being affected by increases or decreases in the power consumption of the load device 140.

[Note]
The first feature is a communication device that is a distributed power source installed in a facility connected to a power grid, and comprises a first communication unit that communicates with a power management server that manages the distributed power source used in supply and demand adjustment control to maintain the frequency of the power grid, and a second communication unit that communicates commands with the distributed power source, including an information element that specifies the type of measurement method for the reference power referenced in the control of the distributed power source.

The second feature is that, in the first feature, the control of the distributed power source is a communication device that includes energy management control related to the management of the facility's power demand.

The third feature is that, in the second feature, the method for measuring the reference power referenced in the supply and demand adjustment control is different from the method for measuring the reference power referenced in the energy management control, and is a communication device.

The fourth feature is a communication device in which, in any one of the first to third features, the measurement method includes a first method for measuring at least one of the power supplied from the power system to the facility and the power supplied from the facility to the power system, and a second method for measuring at least one of the power output from the distributed power source and the power input to the distributed power source.

The fifth feature is a communication device in which, in any one of the first to fourth features, the supply and demand adjustment control includes a first control for controlling the power of the distributed power source within the facility, and a second control for controlling the power of the distributed power source from outside the facility.

The sixth feature is a communication device in which, in the fifth feature, the second communication unit communicates commands with the distributed power supply, including an information element specifying a threshold for the frequency deviation of the power system, and the first control includes a control that increases the output of the distributed power supply to a specific power level when the frequency deviation of the power system is below the threshold.

The seventh feature is a communication device in which, in the sixth feature, the threshold value is a value with hysteresis.

The eighth feature is a distributed power supply installed in a facility connected to a power grid, comprising a communication device that communicates with a power management server that manages the distributed power supply used in supply and demand adjustment control to maintain the frequency of the power grid, and a communication unit that executes the communication of commands including information elements that specify the type of measurement method for the reference power referenced in the control of the distributed power supply.

The ninth feature is a communication method comprising: step A, which involves a distributed power source installed in a facility connected to a power grid, and a power management server that manages the distributed power source used in supply and demand adjustment control to maintain the frequency of the power grid; and step B, which involves communicating a command containing an information element specifying the type of measurement method for the reference power referenced in the control of the distributed power source to the distributed power source.

1…Power Management System, 11…Network, 12…Power System, 100…Facilities, 110…Solar Panels, 120…Energy Storage Devices, 121…BT, 122…Monitoring Unit, 123…Communication Unit, 124…Control Unit, 130…Fuel Cell Device, 140…Load Equipment, 160…Gateway Device, 190A…Measurement Device, 190B…Measurement Device, 200…Power Management Server, 210…Communication Unit, 220…Management Unit, 230…Control Unit

Claims (7)

A communication device that communicates with distributed power sources used in energy management control related to the management of power demand for facilities connected to the power grid,
A first communication unit that communicates with a power management server that manages the distributed power sources used in supply and demand adjustment control to maintain the frequency of the power system,
A communication device comprising: a second communication unit that transmits to the distributed power supply a command including an information element that specifies the type of measurement method for the reference power referenced in the control of the distributed power supply. The communication device according to claim 1, wherein the method for measuring the reference power referenced in the supply and demand adjustment control differs from the method for measuring the reference power referenced in the energy management control. The communication device according to claim 1, wherein the measurement method includes a first method for measuring at least one of the power supplied from the power system to the facility and the power supplied from the facility to the power system, and a second method for measuring at least one of the power output from the distributed power source and the power input to the distributed power source. The communication device according to claim 1, wherein the supply and demand adjustment control includes a first control for controlling the power of the distributed power source within the facility, and a second control for controlling the power of the distributed power source from outside the facility. The second communication unit transmits a command to the distributed power supply that includes an information element specifying a threshold for the frequency deviation of the power system.
The communication device according to claim 4, wherein the first control includes a control that increases the output of the distributed power supply to a specific power when the frequency deviation of the power system is below the threshold. The communication device according to claim 5, wherein the threshold value is a value having hysteresis. A communication method for communicating with distributed power sources used in energy management control related to the management of power demand for facilities connected to a power grid,
Step A involves communicating with a power management server that manages the distributed power sources used in supply and demand adjustment control to maintain the frequency of the power system,
A communication method comprising step B, which involves sending a command to the distributed power supply that includes an information element specifying the type of measurement method for a reference power referenced in the control of the distributed power supply.