JP7575998B2 - Power management server and power management method - Google Patents

Description

The present invention relates to a power management server and a power management method.

In recent years, technology has been known that suppresses the flow of power from a power system to a facility in order to maintain the power supply and demand balance of the power system. In order to maintain the power supply and demand balance of the power system, technology has been proposed that controls the discharge power of storage devices installed in each of two or more facilities so that the flow power of the two or more facilities becomes a target power.

Specifically, when the power that can be adjusted by the discharge power of the power storage device (hereinafter, adjustable power) is greater than the power that needs to be adjusted to maintain the power supply and demand balance in the power grid (hereinafter, adjustment required power), the power management server sequentially controls some of the facilities included in the two or more facilities (for example, Patent Document 1).

International Publication No. 2019/107435

However, in the above-mentioned technology, when controlling the energy storage device, it is necessary to refer to values measured by a measuring device that measures tidal flow power.

Against this background, the inventors discovered that the measurement granularity of the measuring device is too coarse, making it impossible to appropriately control the power supply and demand balance in the power grid.

The present invention has been made to solve the above-mentioned problems, and aims to provide a power management server and a power management method that enable appropriate control of the power supply and demand balance in a power grid.

The gist of the disclosure is that a power management server includes a receiver that receives information elements indicating power related to a facility in a first period from a measuring device that measures the power related to the facility at a predetermined granularity, and a controller that controls a distributed power source installed in the facility, and when the predetermined granularity is coarser than a threshold value, the controller executes a first control that controls the distributed power source based on an integrated value of power related to the facility in a second period longer than the first period.

The gist of the disclosure is that it is a power management method comprising step A of receiving, in a first period, information elements indicating power related to a facility from a measuring device that measures the power related to the facility at a predetermined granularity, and step B of controlling a distributed power source installed in the facility, and step A includes a step of executing a first control to control the distributed power source based on an integrated value of power related to the facility in a second period longer than the first period when the predetermined granularity is coarser than a threshold value.

The present invention provides a power management server and a power management method that enable appropriate control of the power supply and demand balance in a power grid.

FIG. 1 is a diagram showing a power management system 100 according to an embodiment. FIG. 2 is a diagram showing a facility 300 according to the embodiment. FIG. 3 is a diagram showing the lower level management server 200 according to the embodiment. FIG. 4 is a diagram illustrating a local control device 360 according to an embodiment. FIG. 5 is a diagram for explaining an application scene according to the embodiment. FIG. 6 is a diagram for explaining an application scene according to the embodiment. FIG. 7 is a diagram illustrating a power management method according to an embodiment. FIG. 8 is a diagram for explaining the first modification. FIG. 9 is a diagram for explaining the first modification. FIG. 10 is a diagram for explaining the second modification. FIG. 11 is a diagram for explaining the second modification. FIG. 12 is a diagram for explaining the second modification. FIG. 13 is a diagram for explaining the third modification.

The following describes the embodiments with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic.

[Embodiment]
(Power Management System)
A power management system according to an embodiment will be described below.

As shown in FIG. 1, the power management system 100 has a lower management server 200, a facility 300, and an upper management server 400. In FIG. 1, facilities 300A to 300C are shown as examples of the facility 300.

Each facility 300 is connected to the power system 110. Hereinafter, the flow of power from the power system 110 to the facility 300 is referred to as forward flow, and the flow of power from the facility 300 to the power system 110 is referred to as reverse flow. The forward flow power from the power system 110 to the facility 300 may be referred to as demand power. Demand power may be a concept that includes reverse flow power from the facility 300 to the power system 110. In such a case, the forward flow power may be represented as a positive value, and the reverse flow power may be represented as a negative value.

The lower management server 200, the facility 300, and the upper management server 400 are connected to a network 120. The network 120 may provide a line between the lower management server 200 and the facility 300, and a line between the lower management server 200 and the upper management server 400. For example, the network 120 may include the Internet. The network 120 may also include a dedicated line such as a VPN (Virtual Private Network).

The lower-level management server 200 is an example of a power management server that adjusts the supply and demand balance of the power system 110. The lower-level management server 200 is a server managed by a business operator such as a power generation business operator, a power transmission and distribution business operator, a retail business operator, or a resource aggregator. The resource aggregator may be a power business operator that provides reverse flow power to a power generation business operator, a power transmission and distribution business operator, a retail business operator, etc. in a VPP (Virtual Power Plant). The resource aggregator may be a power business operator that generates reduced power of the forward flow power (power consumption) of the facility 300 managed by the resource aggregator.

The lower-level management server 200 transmits a control message to the local control device 360 installed in the facility 300 to instruct the control of the distributed power source (e.g., the solar cell device 310, the power storage device 320, or the fuel cell device 330) installed in the facility 300. For example, the lower-level management server 200 may transmit a power flow control message requesting control of a power flow, or may transmit a reverse flow control message requesting control of a reverse flow. Furthermore, the lower-level management server 200 may transmit a power source control message to control the operating state of the distributed power source. The degree of control of the power flow or reverse flow may be expressed as an absolute value (e.g., XX kW) or a relative value (e.g., XX%). Alternatively, the degree of control of the power flow or reverse flow may be expressed at two or more levels. The degree of control of the power flow or reverse flow may be expressed by a power price (RTP; Real Time Pricing) determined by the current power supply and demand balance, or by a power price (TOU; Time Of Use) determined by the past power supply and demand balance.

As shown in FIG. 2, the facility 300 has a solar cell device 310, a power storage device 320, a fuel cell device 330, a load device 340, a local control device 360, and a measurement device 390.

The solar cell device 310 is a distributed power source that generates power in response to light such as sunlight. The solar cell device 310 may be an example of a distributed power source used in a VPP. For example, the solar cell device 310 is composed of a PCS (Power Conditioning System) and solar panels.

The power storage device 320 is a distributed power source that charges and discharges power. The power storage device 320 may be an example of a distributed power source used in a VPP. For example, the power storage device 320 is composed of a PCS and a storage battery cell.

The fuel cell device 330 is a distributed power source that generates power using fuel. The fuel cell device 330 may be an example of a distributed power source used in a VPP. For example, the fuel cell device 330 is composed of a PCS and a fuel cell.

For example, the fuel cell device 330 may be a solid oxide fuel cell (SOFC: Solid Oxide Fuel Cell), a polymer electrolyte fuel cell (PEFC: Polymer Electrolyte Fuel Cell), a phosphoric acid fuel cell (PAFC: Phosphoric Acid Fuel Cell), or a molten carbonate fuel cell (MCFC: Molten Carbonate Fuel Cell).

Load devices 340 are devices that consume power. For example, load devices 340 are air conditioners, lighting devices, AV (audio-visual) devices, etc.

The local control device 360 is a device (EMS; Energy Management System) that manages the power of the facility 300. The local control device 360 may control the operating state of the solar cell device 310, the operating state of the power storage device 320, or the operating state of the fuel cell device 330. Details of the local control device 360 will be described later (see FIG. 4).

The measuring device 390 is an example of a measuring device that measures the power related to the facility 300 at a predetermined granularity. The measuring device 390 may measure the forward flow power from the power system 110 to the facility 300 as the power related to the facility 300. In other words, the power related to the facility 300 may be considered to be the demand power of the facility 300. The measuring device 390 may measure the reverse flow power from the facility 300 to the power system 110 as the power related to the facility 300. The value measured by the measuring device 390 may be referred to as a measurement value. The measuring device 390 may transmit a message including an information element indicating the power related to the facility 300 at a first period (e.g., 1 minute). The measuring device 390 may transmit the message to the local control device 360 or to the lower management server 200. The measuring device 390 may transmit the message autonomously or in response to a request from the transmission destination. For example, the measuring device 390 may be a Smart Meter belonging to the upper management server 400. The specified granularity may be referred to as the measurement granularity or as the demand measurement granularity.

Here, the measuring device 390 measures the integrated power value for the facility 300. In such a case, the specified granularity may be considered to be a power range within which the measuring device 390 can distinguish the integrated value. For example, when the mth integrated value is between n×power range and n+1×power range, the measuring device 390 identifies n×power range as the integrated value.

For example, if the specified granularity is 15 kWh, the measuring device 390 specifies the integrated value with 15 kWh as the smallest unit. Therefore, the integrated value measured by the measuring device 390 is an integer multiple of 15 kWh (0 kWh, 15 kWh, 30 kWh, 45 kWh, etc.). Furthermore, assuming a case in which the integrated value of the actual power demand from 12:00 to 12:01 is 25 kWh and the integrated value of the actual power demand from 12:01 to 12:02 is 25 kWh, the measuring device 390 measures an integrated value of 15 kWh at 12:01 and an integrated value of 45 kWh at 12:02.

The upper management server 400 is an entity that provides infrastructure such as the power grid 110, and may be a server managed by a power generation company or a power transmission and distribution company. The upper management server 400 may be a server managed by an aggregator controller that controls a resource aggregator.

The upper management server 400 transmits an adjustment message to the lower management server 200 requesting an adjustment of the supply and demand balance of the power grid 110. The adjustment message may include a message requesting a reduction in the power demand of the power grid (a DR (Demand Response) message). The adjustment message may include a message requesting a reduction in the power supply of the power grid (an output suppression message).

The adjustment message may include an information element that specifies the adjustment request power that requests an adjustment of the supply and demand balance of the power system 110. The adjustment request power may be represented by the power to be adjusted in the target period. The adjustment request power may be determined based on the baseline power. The baseline power may be an average value of the demand power for a certain period before the transmission of the adjustment message. The certain period may be determined according to the actual situation of the negawatt trading, or may be determined between the lower management server 200 and the upper management server 400. Alternatively, the adjustment request power may be determined based on a forecast value of the demand power in the target period.

For example, the adjustment request power may be represented by an instantaneous value of the power to be adjusted from the baseline power. The instantaneous value of the adjustment request power may be referred to as an AC command value.

In the embodiment, communication between the lower management server 200 and the local control device 360 is performed according to a first protocol. On the other hand, communication between the local control device 360 and the distributed power source (the solar cell device 310, the power storage device 320, or the fuel cell device 330) is performed according to a second protocol different from the first protocol. For example, the first protocol may be a protocol conforming to Open ADR (Automated Demand Response) or a unique dedicated protocol. For example, the second protocol may be a protocol conforming to ECHONET Lite (registered trademark), SEP (Smart Energy Profile) 2.0, KNX, or a unique dedicated protocol. For example, both the first protocol and the second protocol may be unique dedicated protocols, as long as they are protocols created according to different rules. However, the first protocol and the second protocol may be protocols created according to the same rules.

(lower management server)
The lower level management server according to the embodiment will be described below. As shown in Fig. 3, the lower level management server 200 includes a management unit 210, a communication unit 220, and a control unit 230. The lower level management server 200 may be an example of a VTN (Virtual Top Node).

The management unit 210 is composed of a storage medium such as a non-volatile memory and/or a hard disk drive (HDD).

For example, the management unit 210 manages data on the facility 300 managed by the lower management server 200. The facility 300 managed by the lower management server 200 may be a facility 300 that has a contract with the entity that manages the lower management server 200. For example, the data on the facility 300 may be the demand power supplied to the facility 300 from the power system 110, or the power reduced in each facility 300 in response to a reduction request (DR) for the demand power of the entire power system 110. The data on the facility 300 may be the type of distributed power source (solar cell device 310, power storage device 320, or fuel cell device 330) installed in the facility 300, the specifications of the distributed power source (solar cell device 310, power storage device 320, or fuel cell device 330) installed in the facility 300, etc. The specifications may be the rated power generation (W) of the solar cell device 310, the maximum output power (W) of the power storage device 320, and the maximum output power (W) of the fuel cell device 330. Furthermore, the data on the facility 300 may be the output power instructed to the distributed power source in the past. For example, when the distributed power source is a power storage device 320, the data related to the facility 300 may be the discharge power instructed to the power storage device 320. The data related to the facility 300 may be the degree of deterioration of the distributed power source. For example, when the distributed power source is a power storage device 320, the data related to the facility 300 may be the SOH (State Of Health) of the power storage device 320.

The communication unit 220 is configured by a communication module. The communication module may be a wireless communication module that complies with standards such as IEEE802.11a/b/g/n, ZigBee, Wi-SUN, LTE, and 5G, or may be a wired communication module that complies with standards such as IEEE802.3.

The communication unit 220 communicates with the local control device 360 via the network 120. As described above, the communication unit 220 communicates according to the first protocol. For example, the communication unit 220 transmits a first message to the local control device 360 according to the first protocol. The communication unit 220 receives a first message response from the local control device 360 according to the first protocol.

For example, the communication unit 220 receives a message from the facility 300 (e.g., the local control device 360, the measurement device 390) including an information element indicating the demand power supplied from the power system 110 to the facility 300. The demand power may be a value measured by the measurement device 390 described above. The demand power may be a value obtained by subtracting the output power of the distributed power sources (the solar cell device 310, the storage device 320, and the fuel cell device 330) from the power consumption of the load device 340.

The control unit 230 may include at least one processor. The at least one processor may be configured by a single integrated circuit, or may be configured by multiple circuits (such as integrated circuits and/or discrete circuits) communicatively connected.

For example, the control unit 230 controls each component of the lower-level management server 200. Specifically, the control unit 230 instructs the local control device 360 installed in the facility 300 to control the distributed power sources (solar cell device 310, power storage device 320, or fuel cell device 330) installed in the facility 300 by sending a control message. The control message may be a power flow control message, a reverse power flow control message, or a power source control message, as described above.

(Local Control Device)
A local control device according to an embodiment will be described below. As shown in Fig. 4, the local control device 360 includes a first communication unit 361, a second communication unit 362, and a control unit 363. The local control device 360 may be an example of a VEN (Virtual End Node).

The first communication unit 361 is configured by a communication module. The communication module may be a wireless communication module that complies with standards such as IEEE802.11a/b/g/n, ZigBee, Wi-SUN, LTE, and 5G, or may be a wired communication module that complies with standards such as IEEE802.3.

For example, the first communication unit 361 communicates with the lower management server 200 via the network 120. As described above, the first communication unit 361 communicates according to the first protocol. For example, the first communication unit 361 receives a first message from the lower management server 200 according to the first protocol. The first communication unit 361 sends a first message response to the lower management server 200 according to the first protocol.

The second communication unit 362 is configured by a communication module. The communication module may be a wireless communication module that complies with standards such as IEEE802.11a/b/g/n, ZigBee, Wi-SUN, LTE, and 5G, or may be a wired communication module that complies with standards such as IEEE802.3.

For example, the second communication unit 362 communicates with the distributed power source (the solar cell device 310, the power storage device 320, or the fuel cell device 330). As described above, the second communication unit 362 communicates according to the second protocol. For example, the second communication unit 362 transmits a second message to the distributed power source according to the second protocol. The second communication unit 362 receives a second message response from the distributed power source according to the second protocol.

The control unit 363 may include at least one processor. The at least one processor may be configured by a single integrated circuit, or may be configured by multiple circuits (integrated circuits(s) and/or discrete circuits(s)) communicatively connected.

For example, the control unit 363 controls each component installed in the local control device 360. Specifically, the control unit 363 instructs the devices to set the operating state of the distributed power source by sending a second message and receiving a second message response in order to control the power of the facility 300. The control unit 363 may instruct the distributed power source to report information about the distributed power source by sending a second message and receiving a second message response in order to manage the power of the facility 300.

(Applicable scenes)
In the following, a description will be given of an application scene of the embodiment. In the application scene, a method for solving the problem caused by the above-mentioned predetermined granularity will be described. In the application scene, a case in which the above-mentioned lower level management server 200 controls the power storage device 320 will be exemplified.

Under these assumptions, the communication unit 220 constitutes a receiving unit that receives information elements indicating the power related to the facility 300 in a first cycle. The control unit 230 controls the power storage device 320 installed in the facility 300.

Here, when the predetermined granularity is coarser than the threshold value, the control unit 230 executes a first control to control the power storage device 320 based on an integrated value of power for the facility 300 in a second period longer than the first cycle. The second period may be a unit period (e.g., 30 minutes) for adjusting the supply and demand balance of the power system 110. The second period may be shorter or longer than the unit period.

On the other hand, when the specified granularity is not coarser than the threshold value, the control unit 230 executes a second control that controls the power storage device 320 based on the instantaneous value of the power related to the facility 300. The second control may be a control that is executed in a first period in which a measurement value is received from the measurement device 390. In other words, the second control is superior in real-time performance to the first control.

Here, the control unit 230 converts the integrated value received from the measuring device 390 at a predetermined granularity into an instantaneous value. Specifically, when the first period for receiving the measurement value is t seconds, the control unit 230 converts the integrated value into an instantaneous value according to the formula: integrated value [kWh] = instantaneous value [kW] × t [seconds]/3600 [seconds].

For example, as described above, if the specified granularity is 15 kWh, and the integrated value of the actual power demand from 12:00 to 12:01 is 25 kWh, and the integrated value of the actual power demand from 12:01 to 12:02 is 25 kWh, the measuring device 390 measures an integrated value of 15 kWh at 12:01, and 45 kWh at 12:02. In such a case, the control unit 230 specifies 15 kWh as the integrated value from 12:00 to 12:01, and 30 kWh (= 45 kWh - 15 kWh) as the integrated value from 12:01 to 12:02. Under these assumptions, assuming the first cycle is one minute (60 seconds), the control unit 230 will specify 900kW (15kWh x 60) as the instantaneous value from 12:00 to 12:01, and 1800kW (30kWh x 60) as the instantaneous value from 12:01 to 12:02.

In addition, if the specified granularity is 15 kWh, the specified granularity for 1 minute may be considered to be 900 kW, and the specified granularity for 30 minutes may be considered to be 30 kW.

The first and second controls described above will be explained below with reference to the drawings. Here, the power related to the facility 300 is referred to as the power demand.

For example, the control unit 230 controls the power storage device 320 based on a target value during the target period. The target value is set based on the predicted value of power demand during the target period. The target value is a target value set in the above-mentioned DR, etc. The predicted value of power demand used to set the target value is a value predicted at a first timing prior to the target period. The predicted value of power demand may be notified from the facility 300 to the lower-level management server 200, or may be predicted by the lower-level management server 200. Furthermore, a case will be described in which the length of the target period is the same as the length of the unit period described above. An example of the target period is 12:00 to 12:30.

In this context, to explain the usefulness of the first control, we will first explain the second control with reference to Figure 5.

As shown in FIG. 5, in the second control, the control unit 230 controls the power storage device 320 based on the instantaneous value of the power (demanded power) for the facility 300. Specifically, when the instantaneous value of the demanded power is smaller than the target value, the control unit 230 controls the power storage device 320 to perform a charging operation. On the other hand, when the instantaneous value of the demanded power is larger than the target value, the control unit 230 controls the power storage device 320 to perform a discharging operation.

In this way, the second control has excellent real-time characteristics and contributes to stabilizing the supply and demand balance of the power system 110 in an instantaneous sense as well. However, if the specified granularity is coarser than the threshold value, an error occurs between the measured value of the power demand and the actual value of the power demand. For example, if a case is assumed in which the integrated value of the power demand in a unit period is brought closer to the target value of the power demand, it is conceivable that the second control, which has high real-time characteristics, may not be able to stabilize the supply and demand balance of the power system 110. Such a situation may occur when the difference between the measured value and the target value is greater than the maximum dischargeable power or the maximum chargeable power. Furthermore, such a situation may also occur depending on the specified granularity (the difference between the measured value and the actual value).

In order to solve the above-mentioned problems, in the embodiment, the control unit 230 executes the above-mentioned first control when the predetermined granularity is coarser than the threshold value. Specifically, as shown in FIG. 6, in the first control, the control unit 230 controls the power storage device 320 based on the integrated value of the power (demand power) related to the facility 300. That is, the control unit 230 controls the power storage device 320 so as to bring the integrated value of the demand power closer to the target value. It should be noted here that the target value shown in FIG. 6 is the target value shown in FIG. 5 converted from an instantaneous value to an integrated value, and is the same as the target value shown in FIG. 5.

With this configuration, even if there are cases where the difference between the measured value and the target value is greater than the maximum dischargeable power or the maximum chargeable power, it is easy to bring the integrated value of power demand closer to the target value of power demand at the end of the unit period. In other words, it is possible to stabilize the supply and demand balance of the power system 110 for a unit period, even at the expense of real-time performance.

(Power Management Method)
The power management method according to the embodiment will be described below, focusing on the operation of the lower level management server 200.

As shown in FIG. 7, in step S10, the lower management server 200 identifies the predetermined granularity of the measuring device 390. The lower management server 200 may identify the predetermined granularity by receiving an information element indicating the predetermined granularity from the measuring device 390. The lower management server 200 may identify the predetermined granularity by user input.

In step S11, the lower management server 200 determines whether the specified granularity is coarser than the threshold. If the specified granularity is coarser than the threshold, the lower management server 200 executes the process of step S12. If the specified granularity is not coarser than the threshold, the lower management server 200 executes the process of step S13.

In step S12, the lower level management server 200 executes a first control to control the power storage device 320 based on the accumulated value of the power for the facility 300 during a second period that is longer than the first cycle (see FIG. 6).

In step S13, the lower level management server 200 executes a second control to control the power storage device 320 based on the instantaneous value of the power related to the facility 300 (see FIG. 5).

(Action and Effects)
In the embodiment, the lower level management server 200 executes the first control when the predetermined granularity is coarser than the threshold value. With this configuration, it is possible to stabilize the supply and demand balance of the power system 110 in a unit period, while sacrificing real-time performance.

In an embodiment, the lower-level management server 200 executes the second control when the specified granularity is not coarser than the threshold value. With this configuration, it is possible to instantaneously stabilize the supply and demand balance of the power system 110 for a unit period.

[Modification 1]
Modification 1 of the embodiment will be described below. Differences from the embodiment will be mainly described below.

In the first modified example, a method for correcting the accumulated value (measured value) of power for the facility 300 is described. Here, a method for the lower management server 200 to correct the accumulated value (measured value) of the power demand is illustrated. Such a correction may be applied in the first control described above.

Specifically, the control unit 230 described above corrects the integrated value of power for the facility 300 based on a prediction error that occurs in a reference period that precedes the target period. The prediction error is the difference between the predicted value of power for the facility 300 in the reference period and the actual value of power for the facility 300 in the reference period. The control unit 230 may correct the integrated value of power for the facility 300 based on the above-mentioned predetermined granularity.

Here, the length of the reference period may be the same as the length of the target period. The reference period may be a unit period immediately preceding the target period. As described above, the predicted value of the power demand is used to set the target value.

The following describes such a correction method with reference to the drawings. An example of the target period is 12:00 to 12:30, and an example of the reference period is 11:30 to 12:00. Furthermore, an example is given of a case in which the above-mentioned correction is performed at 12:15. Furthermore, an example is given of a case in which the discharge operation of the power storage device 320 is performed to stabilize the supply and demand balance of the power system 110.

First, the control unit 230 determines a prediction error between the predicted value of the power demand in the reference period and the actual value of the power demand in the reference period, as shown in FIG. 8. The predicted value and the actual value may be expressed as average values in the reference period. The predicted value of the power demand may be expressed as power demand (predicted value), and the actual value of the power demand may be expressed as power demand (actual value).

Secondly, the control unit 230 determines a corrected predicted value of the power demand by correcting the predicted value of the power demand in the target period by the prediction error. The predicted value and the corrected predicted value may be expressed as average values in the target period. For example, when the prediction error in the reference period is expressed by a prediction error rate such as "predicted value/actual value", the corrected predicted value may be calculated by multiplying the predicted value in the target period by the reciprocal of the prediction error rate. Alternatively, when the prediction error in the reference period is expressed by an absolute difference value such as "actual value-predicted value", the corrected predicted value may be calculated by adding the absolute difference value to the predicted value in the target period.

Thirdly, the control unit 230 determines the expected discharge power of the power storage device 320 based on the difference between the corrected predicted value and the target value of the power demand in the target period. Next, the control unit 230 determines the ratio between the expected discharge power and the maximum dischargeable power (expected discharge power/maximum dischargeable power). The control unit 230 uses the determined ratio as a correction coefficient. For example, if the expected discharge power is 40 kW and the maximum dischargeable power is 50 kW, the control unit 230 determines 0.8 (=40/50) as the correction coefficient. The expected discharge power is calculated power and differs from the actual discharge power in the target period. The expected discharge power may be referred to as ideal discharge power. The target value of the power demand may be written as power demand (target value).

In the first modification, under such a premise, attention is paid to the error (the difference between the measured value of the power demand and the actual value of the power demand) that occurs due to the above-mentioned predetermined granularity. Such an error is accumulated during the target period.

Therefore, as shown in Figure 9, the cumulative power demand determined by the measurements may be less than the cumulative power demand. However, these differences are unknown.

In order to solve such problems, in the first modification, as shown in FIG. 9, the control unit 230 specifies a correction value for correcting the integrated value (measured value) of the power demand. For example, consider a case where the predetermined granularity based on the integrated value is 15 kWh. In such a case, the control unit 230 specifies a correction value (13.5=7.5+7.5×0.8) for correcting the integrated value (measured value) of the power demand based on the above-mentioned correction coefficient (0.8) and the predetermined granularity (15 kWh). The first term "7.5" is an item for correcting the measured value based on the predetermined granularity. Here, a case is illustrated where the value for correcting the measured value based on the predetermined granularity is the predetermined granularity×1/2, but the value for correcting the measured value based on the predetermined granularity may be a value other than the predetermined granularity×1/2 under the condition that the correction value does not exceed the predetermined granularity. The sign "+" means that the storage device 320 needs to be discharged. If the storage device 320 needs to be charged, the sign may be "-". The second term, "7.5 x 0.8", is used to correct the measurement value for the forecast error in the reference period.

Furthermore, the control unit 230 determines the corrected integrated value of the power demand (corrected power demand) by adding the determined correction value to the integrated value (measured value) of the power demand. In the first control described above, the control unit 230 controls the power storage device 320 so that the corrected integrated value of the power demand approaches the target value.

In the above-mentioned modified example 1, a case where the predicted value of the power demand is greater than the actual value of the power demand is exemplified. However, modified example 1 is not limited to this. Modified example 1 may also be applied to a case where the predicted value of the power demand is less than the actual value of the power demand. In such a case, the item for correcting the measurement value based on the prediction error of the reference period may be subtracted from the item for correcting the measurement value based on a predetermined granularity.

In the above-mentioned modified example 1, the discharging operation of the power storage device 320 is exemplified. However, modified example 1 is not limited to this. Modified example 1 may also be applied to the charging operation of the power storage device 320.

(Formulation)
The following describes an example of formulation regarding the discharging operation (or charging operation) of the power storage device 320. For example, the charging power or discharging power (hereinafter, charging/discharging power) of the power storage device 320 can be expressed by the following formula.

Here, the meanings of each abbreviation are as follows:

(Action and Effects)
In the first modification, the lower level management server 200 corrects the integrated value of the power (power demand) for the facility 300 based on the prediction error occurring in the reference period prior to the target period. With this configuration, the prediction error occurring in the reference period is taken into consideration, so that the integrated value of the power demand can be appropriately corrected. Therefore, the accuracy of the first control described above is improved.

In the first modification, the lower-level management server 200 corrects the accumulated value of the power (power demand) for the facility 300 based on a predetermined granularity. With this configuration, the accumulated value of the power demand can be appropriately corrected because the underestimation of the accumulated value of the power demand caused by the predetermined granularity is taken into account. Therefore, the accuracy of the first control described above is improved.

[Modification 2]
The second modification of the embodiment will be described below, focusing mainly on the differences from the embodiment.

In the second modification, a method for controlling the remaining charge (hereinafter referred to as SOC (State of Charge)) of the power storage device 320 will be described.

In modified example 2, the power storage device 320 is controlled based on a target value during the target period. We focus on a case where the target value is set based on a predicted value of power demand during the target period. The predicted value of power demand used to set the target value is a value predicted at a first timing prior to the target period. Although not particularly limited, the first timing may be noon (12:00) on the day before the day that includes the target period.

In this context, at the first timing when the target value is set, the control unit 230 executes a setting process to set a target remaining power storage amount (hereinafter, target SOC) of the power storage device 320 required at the start timing of the target period based on a predicted value of the power (demanded power) for the facility 300 during the target period. The target SOC may be set taking into consideration not only the discharging operation during the target period but also the charging operation during the target period.

At a second timing that is later than the first timing, the control unit 230 identifies a corrected predicted value of the power (demand power) for the facility 300 during the target period, and executes a correction process to correct the target SOC of the power storage device 320 required at the start timing of the target period based on the identified corrected predicted value. Although not particularly limited, the second timing may be a timing a predetermined time (1 hour, 3 hours, 6 hours, etc.) before the start timing of the target period. Although not particularly limited, the corrected predicted value may be the difference between the predicted value of the power demand at the first timing and the predicted value of the power demand at the second timing. The prediction of the power demand may be performed based on meteorological information (e.g., temperature, humidity, solar radiation, weather, etc.) for a day including the target period.

For example, as shown in FIG. 10, the lower management server 200 sets a target SOC at a first timing. The lower management server 200 corrects the target SOC at a second timing. When the predicted value of the power demand at the first timing is smaller than the predicted value of the power demand at the second timing, the lower management server 200 may correct the target SOC so that the target SOC becomes smaller. With this configuration, during the target period, the discharge capacity of the power storage device 320 decreases, but the storage capacity of the power storage device 320 increases.

For example, as shown in FIG. 11, the lower management server 200 sets a target SOC at a first timing. The lower management server 200 corrects the target SOC at a second timing. When the predicted value of the power demand at the first timing is greater than the predicted value of the power demand at the second timing, the lower management server 200 may correct the target SOC so that the target SOC is larger. With this configuration, during the target period, the storage capacity of the power storage device 320 decreases, but the discharge capacity of the power storage device 320 increases.

Furthermore, when a specific condition is satisfied, the lower level management server 200 may execute a maximization process to maximize the target SOC of the power storage device 320 without executing the above-mentioned correction process. The specific condition may be that a disaster (such as a typhoon or heavy snow) is predicted to occur during the target period. The specific condition may be that a power outage (planned power outage) is predicted during the target period.

For example, as shown in FIG. 12, the lower management server 200 sets a target SOC at a first timing. If the lower management server 200 determines that a specific condition is satisfied at a second timing, it maximizes the target SOC. With this configuration, it is possible to secure the SOC of the power storage device 320 in preparation for disasters, power outages, and the like.

[Modification 3]
The third modification of the embodiment will be described below, focusing mainly on the differences from the first modification.

Specifically, in the first modification, the control unit 230 corrects the integrated value of the power for the facility 300 based on a prediction error that occurs in a reference period that precedes the target period. The prediction error is the difference between the predicted value of the power for the facility 300 in the reference period and the actual value of the power for the facility 300 in the reference period.

In contrast, in Modification Example 3, we consider a case in which a correction value for correcting the integrated power value for facility 300 cannot be properly calculated due to a discrepancy between the power demand (predicted value) and the power demand (actual value). For example, as shown in FIG. 13, a case can be considered in which the power demand (actual value) in the reference period is greater than the power demand (predicted value) in the reference period, while the power demand (actual value) in the target period is less than the power demand (predicted value) in the target period. In such a case, the power demand (predicted value) in the target period is corrected based on the prediction error in the reference period (corrected predicted value in FIG. 13), and therefore the correction value may become too large.

In FIG. 13, the corrected predicted value, the power demand (predicted value), the power demand (actual value), and the power demand (target value) are expressed as average values in the target period. The power demand (actual value) is the average value of the power demand (instantaneous value), and the power demand (instantaneous value) may be a measurement value measured by the measuring device 390.

In such a case, the actual value of the charging and discharging power is represented by the difference between the demand power (actual value) and the demand power (target value). The expected value of the charging and discharging power is represented by the difference between the corrected predicted value and the demand power (target value). Since the corrected predicted value is calculated based on the prediction error in the reference period, the expected value of the charging and discharging power is calculated based on the prediction error in the reference period. The actual value of the charging and discharging power may be expressed as charging and discharging power (actual value), and the expected value of the charging and discharging power may be expressed as charging and discharging power (estimated value).

Under these assumptions, the control unit 230 described above calculates the actual value of the charging and discharging power of the power storage device 320 during the target period, and calculates the expected value of the charging and discharging power of the power storage device 320 during the target period based on the prediction error that occurs in a reference period prior to the target period. The control unit 230 corrects the integrated value of power for the facility 300 during the target period based on the value obtained by multiplying the actual value of the charging and discharging power and the expected value of the charging and discharging power by a specific coefficient. The coefficients shown below may be used as the specific coefficient.

In the first option, the specific coefficient may include a first coefficient that is multiplied by the expected value of the charging and discharging power, and a second coefficient that is multiplied by the actual value of the charging and discharging power.

In the second option, the specific coefficient may include a third coefficient that is multiplied by the ratio between the actual value of the charging and discharging power and the expected value of the charging and discharging power.

In a third option, the specific coefficients may include the first coefficient, the second coefficient, and the third coefficient described above.

Here, the specific coefficient may change depending on the time that has passed since the start of the target period.

For example, the first coefficient may be defined so that the shorter the time that has elapsed since the start timing of the target period, the larger the value, and the longer the time that has elapsed since the start timing of the target period, the smaller the value. In other words, the first coefficient may be defined so that the shorter the time that has elapsed since the start timing of the target period, the greater the influence of the prediction error in the reference period, and the longer the time that has elapsed since the start timing of the target period, the smaller the influence of the prediction error in the reference period.

The second coefficient may be defined so that the shorter the time that has passed since the start of the target period, the smaller the value, and the longer the time that has passed since the start of the target period, the larger the value. In other words, the second coefficient may be defined so that the shorter the time that has passed since the start of the target period, the smaller the influence of the measurement value measured by the measuring device 390, and the longer the time that has passed since the start of the target period, the greater the influence of the measurement value measured by the measuring device 390.

When the ratio is expressed as the actual value of charging and discharging power/the estimated value of charging and discharging power, the third coefficient may be defined in a similar way to the second coefficient so that the shorter the time that has elapsed since the start timing of the target period, the smaller the value, and the longer the time that has elapsed since the start timing of the target period, the larger the value.When the ratio is expressed as the estimated value of charging and discharging power/the actual value of charging and discharging power, the same way to the first coefficient, the shorter the time that has elapsed since the start timing of the target period, the larger the value, and the longer the time that has elapsed since the start timing of the target period, the smaller the value. Alternatively, the third coefficient may be defined regardless of the time that has elapsed since the start timing of the target period. For example, the third coefficient may be defined based on the remaining amount of stored power in the power storage device 320.

The range that the correction value can take may be a range that does not fall below the specified granularity on the negative side, and does not exceed the specified granularity on the positive side. When the correction value falls below the specified granularity on the negative side, the specified granularity (negative value) may be used as the correction value. Similarly, when the correction value exceeds the specified granularity on the positive side, the specified granularity (positive value) may be used as the correction value. Furthermore, the first coefficient, the second coefficient, and the third coefficient may be defined so that the correction value falls within a range that does not fall below the specified granularity on the negative side, and does not exceed the specified granularity on the positive side.

The first, second, and third options may be selected according to the specified granularity of the measuring device 390, the trend of the power demand of the facility 300, the storage capacity of the power storage device 320, etc. The possible ranges of the first, second, and third coefficients may be defined according to the specified granularity of the measuring device 390, the trend of the power demand of the facility 300, the storage capacity of the power storage device 320, etc.

(Formulation)
An example of a formulation for the above-mentioned correction value will be described below. For example, the correction value can be expressed by any of the following equations.

In addition, in Option 1 to Option 3, the meanings of other abbreviations are the same as those in Modification Example 1. However, it should be noted that the correction value (P _da ) satisfies the condition of -P _dg < P _da < P _dg . When the calculated correction value (P _da ) is below -P _dg , -P _dg may be used as the correction value (P _da ). When the calculated correction value (P _da ) is above P _dg , P _dg may be used as the correction value (P _da ). Furthermore, the first coefficient (α _t ), the second coefficient (β _t ), and the third coefficient (γ _t ) may be defined so as to satisfy the condition of -P _dg < P _da < P _dg . In other words, the first coefficient (α _t ), the second coefficient (β _t ), and the third coefficient (γ _t ) may be defined so that the possible range of the term multiplied by P _dg is from -1 to 1.

(Action and Effects)
In the third modification, the lower level management server 200 corrects the accumulated power value for the facility 300 in the target period based on the actual value of the charge/discharge power and the estimated value of the charge/discharge power multiplied by a specific coefficient. With this configuration, not only the correction using the prediction error in the reference period (i.e., the correction of the estimated value of the charge/discharge power) but also the actual value of the charge/discharge power is taken into consideration, so that even if the prediction error in the reference period has a tendency to differ from the prediction error in the target period, the correction value for correcting the accumulated power value for the facility 300 can be appropriately calculated.

[Other embodiments]
The present invention has been described by the above-mentioned disclosure, but the description and drawings forming a part of this disclosure should not be understood as limiting the present invention. From this disclosure, various alternatives to the above-mentioned disclosure, embodiments and operating techniques will be apparent to those skilled in the art.

For example, the lower management server 200 may indirectly control the power storage device 320 through the local control device 360. The lower management server 200 may directly control the power storage device 320. A control message for controlling the power storage device 320 may be transmitted via the local control device 360 or may be transmitted without passing through the local control device 360. The power storage device 320 and the local control device 360 may be considered as a power storage device.

In the above disclosure, the measuring device 390 measures an integrated value of power related to the facility 300. However, the above disclosure is not limited to this. The measuring device 390 may measure an instantaneous value of power related to the facility 300. Even in such a case, the above disclosure can be applied because the instantaneous value is measured with a predetermined granularity.

The above disclosure has mainly described a request to reduce forward flow power. However, the above disclosure is not limited to this. The above disclosure may also be applied to a request to reduce reverse flow power (output suppression).

In the above disclosure, a case has been exemplified in which the entity that controls the power storage device 320 is the lower management server 200. However, the above disclosure is not limited to this. The entity that controls the power storage device 320 may also be the local control device 360.

In the above disclosure, the storage device 320 is exemplified as a distributed power source. However, the above disclosure is not limited to this. The distributed power source may be a solar cell device 310 or a fuel cell device 330. The distributed power source may be a wind power generation device, a geothermal power generation device, a biomass power generation device, etc. In such a case, the charging and discharging power of the storage device 320 may be read as the output power of the distributed power source. The output power may have the same meaning as the discharging power of the storage device 320 and may be a concept that does not include the charging power of the storage device 320. The charging and discharging power and the output power have the same meaning in the sense that they contribute to adjusting the demand power of the facility 300, and may be referred to as contributing power.

In the above disclosure, a case where the first control or the second control is applied to a distributed power source has been described, focusing on one facility 300. However, the above disclosure is not limited to this. Facilities 300 having distributed power sources to which the first control is applied and facilities 300 having distributed power sources to which the second control is applied may be mixed. In other words, the lower-level management server 200 may apply the first control to a distributed power source installed in a facility 300 having a measuring device with a predetermined granularity coarser than the threshold value, and apply the second control to a distributed power source installed in a facility 300 having a measuring device with a predetermined granularity not coarser than the threshold value.

In the above disclosure, the case where the measuring device 390 is a device that measures the forward flow power or reverse flow power of the facility 300 is exemplified. However, the above disclosure is not limited to this. The measuring device 390 may be a device that measures the power consumption of the load device 340 as the power related to the facility 300, or may be a device that measures the output power of a distributed power source. For example, when the measuring device 390 is a device that measures the power consumption of the load device 340, the integrated value or instantaneous value of the power measured by the measuring device 390 may be used for the load following control of the power storage device 320. When the measuring device 390 is a device that measures the charge and discharge power of the power storage device 320, the integrated value or instantaneous value of the charge and discharge power measured by the measuring device 390 may be used for the target power control of the power storage device 320.

Although not specifically mentioned in the above disclosure, the lower-level management server 200 may control the distributed power sources for one facility 300, or may control the distributed power sources for multiple facilities 300. The lower-level management server 200 may determine a target value for controlling the distributed power sources for each facility 300. Furthermore, the lower-level management server 200 may select, from among the multiple power storage devices 320, a power storage device 320 to be used to stabilize the supply and demand balance of the power grid 110.

Although not specifically mentioned in the above disclosure, at least some of the functions of the local control device 360 may be executed by a server located on the network 120. In other words, the local control device 360 may be provided by a cloud service.

Although not specifically mentioned in the above disclosure, power may refer to an instantaneous value of power at a certain timing ((k)W) or an integrated value of power over a certain period of time ((k)Wh), unless otherwise specified.

100...power management system, 110...power system, 120...network, 200...lower management server, 210...management unit, 220...communication unit, 230...control unit, 300...facility, 310...solar cell device, 320...power storage device, 330...fuel cell device, 340...load device, 360...local control device, 361...first communication unit, 362...second communication unit, 363...control unit, 390...measuring device, 400...upper management server

Claims (11)

a receiving unit that receives, in a first period, an information element indicating power related to the facility from a measuring device that measures power related to the facility at a predetermined granularity;
a control unit that controls the distributed power sources installed in the facility,
The control unit is
when the predetermined granularity is coarser than a threshold value, a first control is executed to control the distributed power source based on an integrated value of power related to the facility in a second period that is longer than the first cycle ;
The power management server executes a second control for controlling the distributed power source based on an instantaneous value of power related to the facility when the predetermined granularity is not coarser than a threshold value. The control unit corrects an integrated value of power for the facility in a target period based on a prediction error occurring in a reference period prior to the target period;
The power management server according to claim 1 , wherein the prediction error is a difference between a predicted value of power for the facility in the reference period and an actual value of power for the facility in the reference period. The control unit calculates an actual value of the contributed power of the distributed power source during a target period,
Calculating an estimated value of the distributed power contribution during the target period based on a prediction error occurring during a reference period prior to the target period;
The power management server according to claim 1 , further comprising: a power management unit configured to adjust an integrated value of power for the facility in the target period based on a value obtained by multiplying the actual value of the contributed power and the estimated value of the contributed power by a specific coefficient. The power management server according to claim 3 , wherein the specific coefficients include a first coefficient by which the estimated value of the contributed power is multiplied, and a second coefficient by which the actual value of the contributed power is multiplied. 5. The power management server according to claim 3 , wherein the specific coefficient includes a third coefficient that is multiplied by a ratio between the actual value of the contributed power and the estimated value of the contributed power. The power management server according to claim 3 , wherein the specific coefficient changes depending on the time that has elapsed since a start timing of the target period. The power management server according to claim 2 , wherein the control unit corrects an integrated value of power related to the facility based on the predetermined granularity. The control unit controls the distributed power source based on a target value during the target period;
The power management server according to claim 2 , wherein the target value is set based on a predicted value of power for the facility during the target period. the distributed power source is a power storage device,
The control unit is
a setting process for setting a target remaining amount of the power storage device required at a start timing of the target period based on a predicted value of power for the facility in the target period at a first timing when the target value is set;
9. The power management server according to claim 8, further comprising: a power management unit configured to: determine a corrected predicted value of power for the facility during the target period at a second timing that is later than the first timing; and perform a correction process to correct a target remaining power storage amount of the power storage device required at a start timing of the target period based on the determined corrected predicted value. The power management server according to claim 9 , wherein the control unit is configured to execute a maximization process for maximizing the target remaining power storage amount without executing the correction process when a specific condition is satisfied. A step A of receiving, in a first period, information elements indicating power related to the facility from a measuring device that measures power related to the facility at a predetermined granularity;
and a step B of controlling a distributed power source installed in the facility,
The step A includes:
executing a first control to control the distributed power source based on an integrated value of power related to the facility in a second period longer than the first cycle when the predetermined granularity is coarser than a threshold value ;
and if the predetermined granularity is not coarser than a threshold value, executing a second control to control the distributed power source based on an instantaneous value of power related to the facility .