Power Management System

Abstract

To stabilize a power system by energy management.SOLUTION: A power management system comprises a resource and a control device which controls the resource. The resource comprises a power storage device and is configured to execute energy management by at least one of charge and discharge of the power storage device. The control device estimates an adjustable amount as a power amount of which the resource can be adjusted (S11) and causes the resource to execute the energy management requested by a request signal in a predetermined period (S14) when the request signal for requesting the energy management is received. The request signal shows a power request value for the energy management. The control device determines a power command value to the resource so that the smaller the estimated adjustable amount is, charge power or discharge power by the resource becomes smaller within an allowable range set to the power request value (S13) in the predetermined period.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a power management system. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2020-156149 (Patent Document 1) discloses a control device that causes a resource (for example, an electric vehicle) to perform energy management (for example, a VPP (Virtual Power Plant) service). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-156149 Summary of the Invention [Problem to be solved by the invention]

[0004] Electric power utilities may receive a reward for receiving a request for energy management and implementing the requested energy management. For example, an electric power utility that manages resources that have energy storage devices may receive a reward based on a contract by implementing the requested energy management during a contracted period. Such electric power utilities may contribute to the stabilization of the power system. However, depending on the state of the resources, the resources may not be able to implement the requested energy management. Further improvements to power management systems are desired to stabilize the power system.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to stabilize the power system through energy management. [Means for solving the problem]

[0006] A power management system according to an embodiment of the present disclosure includes a resource and a control device that controls the resource. The resource has a power storage device and is configured to be able to perform energy management by at least one of charging and discharging the power storage device. The control device is configured, upon receiving a request signal requesting energy management, to estimate an adjustable amount, which is an amount of power that the resource can adjust, and to cause the resource to perform the energy management requested by the request signal for a predetermined period of time. The request signal indicates a power request value for energy management. The control device is configured to determine a power command value for the resource such that, within the predetermined period of time, the smaller the estimated adjustable amount, the smaller the charging power or discharging power by the resource within a tolerance range set for the power request value. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to stabilize the power system through energy management. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an overview of a power management system according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a diagram for explaining an energy management method according to an embodiment of the present disclosure. [Figure 3] FIG. 10 is a diagram for explaining the required charge / discharge amount in three cases. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and their description will not be repeated.

[0010] FIG. 1 is a diagram illustrating an overview of a power management system according to an embodiment of the present disclosure. Referring to FIG. 1, the power management system according to this embodiment performs energy management of a power grid PG. This power management system includes a vehicle group 10G including a plurality of vehicles 10, a vehicle group 20G including a plurality of vehicles 20, a supply and demand management system 100 (hereinafter referred to as "system 100"), a resource management system 200 (hereinafter referred to as "system 200"), an electric vehicle management system 300 (hereinafter referred to as "system 300"), a plurality of power supply facilities 510, and a plurality of power supply facilities 520. System 300 includes a processor 310 and a storage device 320. Although not illustrated, systems 100 and 200 also include a processor and a storage device, similar to system 300.

[0011] The power grid PG is a power network constructed by power transmission and distribution facilities. A plurality of power plants are connected to the power grid PG. Each of the power supply facilities 510 and 520 is electrically connected to the power grid PG and receives a supply of power from the power grid PG. Each of the vehicles 10 and 20 is an electric vehicle (xEV) equipped with a power storage device and configured to be able to run using discharged power from the power storage device. When the vehicles 10 and 20 are electrically connected to the power supply facilities 510 and 520, respectively (plugged-in state), they can charge their on-board batteries (power storage devices) using power (power from outside the vehicles) supplied from the power grid PG through the power supply facilities 510 and 520.

[0012] The vehicle 10 and the power supply equipment 510 are, respectively, a V1G type electric vehicle and a power supply equipment (a type that receives a one-way supply of power from the power grid PG). The power supply equipment 510 is, for example, a power outlet type power supply equipment. The vehicle 20 and the power supply equipment 520 are, respectively, a V2G type electric vehicle and a power supply equipment (a type that exchanges power bidirectionally with the power grid PG). The power supply equipment 520 is, for example, a power supply equipment that is integrated with a cable. Each of the vehicles 10 and 20 is, for example, a BEV (electric vehicle). However, this is not limited thereto, and the type of electric vehicle (xEV) included in each of the vehicle groups 10G and 20G is arbitrary.

[0013] The system 300 is configured to be able to communicate with each electric vehicle included in the vehicle groups 10G, 20G. The system 300 may communicate with the vehicles 10, 20 via wired communication via power supply facilities 510, 520, respectively, or may communicate directly with each of the vehicles 10, 20 via wireless communication. In addition, the user of each electric vehicle carries a user terminal 30. The system 300 also communicates with the user terminal 30. The user terminal 30 is, for example, a smartphone, but may also be another terminal.

[0014] Each electric vehicle and each power supply facility shown in FIG. 1 is registered in the system 300. The storage device 320 stores information (specifications, location, status, etc.) about each registered electric vehicle, distinguishing it by the identification information (vehicle ID) of the electric vehicle. The user terminal 30 of each electric vehicle is also linked to the vehicle ID and registered in the system 300. Each electric vehicle transmits vehicle information about itself (for example, detection results from on-board sensors) to the system 300. The user terminal 30 of each electric vehicle also transmits information about the electric vehicle to the system 300. For example, when a user inputs a driving plan or charging plan for an electric vehicle into the user terminal 30, the plan is linked to the identification information of the electric vehicle and registered in the system 300. The storage device 320 also stores information (specifications, location, etc.) about each registered power supply facility, distinguishing it by the identification information of the power supply facility.

[0015] Hereinafter, all electric vehicles managed by the system 300 are collectively referred to as "electric vehicle resources." The system 300 calculates, for the electric vehicle resources, the charge / discharge power (reference value) when not adjusted and the amount of power that the electric vehicle resources can adjust relative to the reference value (chargeable / dischargeable amount), and transmits these to the system 200. The system 200 manages a plurality of distributed energy resources (hereinafter referred to as "DERs") including electric vehicle resources. Hereinafter, all DERs managed by the system 200 are collectively referred to as "EM resources." The EM resources further include DERs other than electric vehicle resources (e.g., stationary energy storage devices). The system 200 calculates, for the EM resources, the charge / discharge power (reference value) when not adjusted and the amount of power that the EM resources can adjust relative to the reference value (chargeable / dischargeable amount), and transmits these to the system 100. The system 100 conducts transactions in the electricity market based on the reference value and the chargeable / dischargeable amount received from the system 200. The system 100 performs settlements for electricity transactions and manages transaction records. Below, we will explain tertiary control reserve-2 as an example of a product traded in the electricity market.

[0016] The tertiary control reserve-2 is traded in the balancing market. In the balancing market, tertiary control reserve-2 is traded, for example, through an auction system, for each of eight blocks, each divided into three-hour blocks. The system 100 submits bids in the balancing market between 12:00 and 14:00 on the day before the target block. Specifically, the system 100 transmits bidding information, including the product (e.g., tertiary control reserve-2), block (one of eight blocks), reference value, and bid amount, to a market system (not shown). The system 100 is then notified of the results at 15:00 on the day of the bidding. If the bid for the product is successful, a contract is reached. The successful bidder for tertiary control reserve-2 in the balancing market is obligated (contractual obligation) to adjust power within the range (contract adjustment range) between the reference value (kW) and the contract amount (kW).

[0017] When the system 100 wins a bid on a product, it registers the reference value in the market system by the submission deadline (for example, one hour before the start time of the target block for which it has won). The system 100 sequentially receives market request signals from the market system requesting energy management during the target block for which it has won (the contract period). The market request signals indicate the power request value arbitrarily requested by the market system within the contract adjustment range. The system 100 performs energy management during the contract period so that the actual adjusted power follows the power request value.

[0018] During the contract period, the market system checks every 30 minutes to ensure that the system 100 (successful bidder) is adjusting (response performance) in accordance with the commands (market demand signals) within the contract adjustment range. If the power demand value changes during the contract period, the successful bidder changes the output to that value within the response time specified in the product requirements. However, the output may deviate from the power demand value as long as it is within the tolerance range. Furthermore, if the power demand value remains the same during the contract period, the successful bidder will continue to output in accordance with the power demand value for at least the duration of the product requirements. For tertiary control capacity-2, the response time is within 45 minutes and the duration is 3 hours (6 periods). If the successful bidder performs energy management using a power storage device, the successful bidder's output will be charging (increased demand) or discharging (increased supply) corresponding to the requested energy management (product). If non-compliance with the requirements is found, the successful bidder will be subject to a specified penalty fee.

[0019] In the example shown in Figure 1, the period from time t1 to time t2 corresponds to the contract period, and the range from the reference value to the contract amount Y corresponds to the contract adjustment range. Line L10 shows the trend of the power request value. Line L11 shows a power value that is smaller than the power request value by a tolerance (lower limit of the tolerance range). Line L12 shows a power value that is larger than the power request value by a tolerance (upper limit of the tolerance range). The tolerance is, for example, 10% of the contract amount Y. The market system transmits a market request signal to the successful bidder at time t0, which is the response time (45 minutes) before time t1. In the example shown in Figure 1, the initial power request value is the contract amount Y, and the power request value is changed at time t3. The range from time t0 to the elapse of the response time (responsive tolerance A), the range from time t3 to the elapse of the response time (responsive tolerance B), and the range corresponding to the tolerance (increase / decrease tolerance) shown by lines L11 and L12 correspond to the range that meets the requirements (tolerance range).

[0020] Upon receiving a market request signal, the system 100 determines the adjustment amount (higher-level instruction amount) required to execute the energy management requested by the market request signal, and determines the power request value (resource instruction amount) to be requested of the EM resource based on the obtained higher-level instruction amount. The system 100 then transmits a first request signal to the system 200, indicating the contract requirements (contract amount, contract period, tolerance, etc.) and the resource instruction amount. Upon receiving the first request signal, the system 200 determines the adjustment amount (required charge / discharge amount) required for the resource instruction amount, and determines the power request value (vehicle group instruction amount) to be requested of the electric vehicle resource based on the obtained required charge / discharge amount. The system 200 then transmits a second request signal to the system 300, indicating the contract requirements and the vehicle group instruction amount. The system 300 controls the electric vehicle resource so that the energy management requested by the second request signal is executed by the process shown in FIG. 2, which will be described later. This hierarchical structure (tree structure) allows many consumers to request energy management. The EM resource may function as a virtual power plant (VPP).

[0021] FIG. 2 is a diagram for explaining the energy management method according to this embodiment. "S" in the flowchart denotes a step. When the system 300 receives the second request signal, it starts the processing flow shown in FIG. 2. In S11, the system 300 estimates the amount of power (chargeable / dischargeable amount) that can be adjusted by the electric vehicle resource during the contract period based on the latest vehicle information (location, amount of stored power, plug-in / plug-out, etc.). In the following S12, the system 300 calculates the required amount of charging / discharging (required amount of adjustment) that is necessary for the energy management requested by the second request signal during the contract period. Specifically, the system 300 calculates the required amount of charging / discharging during the contract period using, for example, equation (3) in FIG. 2 (for details, see FIG. 3, which will be described later). In the next step S13, the system 300 determines a power command value for the electric vehicle resources so that the greater the chargeable / dischargeable amount (S11) relative to the required charge / discharge amount (S12), the greater the power value of the electric vehicle resources (total power of the vehicle groups 10G and 20G) within the allowable range set for the required power value. Specifically, the system 300 determines the power value of the electric vehicle resources (total charge power or total discharge power according to the required energy management) using, for example, equations (1) and (2) in FIG. 2. Equation (1) is "power command value = α × upper limit of allowable range + (1 - α) × lower limit of allowable range." Equation (2) defines "α" in equation (1) as "α = (chargeable / dischargeable amount - K × required charge / discharge amount) / constant." Here, "α" is between 0 and 1. "K" is a safety factor and is greater than 1. As shown in equations (1) and (2), the greater the margin of the chargeable / dischargeable amount relative to the required chargeable / discharge amount, the closer the power command value to the electric vehicle resource is to the upper limit of the allowable range, and the smaller the margin of the chargeable / dischargeable amount relative to the required chargeable / discharge amount, the closer the power command value to the electric vehicle resource is to the lower limit of the allowable range.

[0022] In S14, the system 300 remotely controls each electric vehicle used for energy management in accordance with the power command value for the electric vehicle resource determined in S13. The system 300 transmits a control command to each electric vehicle so that the power value of the electric vehicle resource becomes the power command value. The system 300 may also allocate the power command value for the electric vehicle resource proportionally to each electric vehicle. When the charging power or discharging power of the power storage device in each electric vehicle reaches the command value from the system 300, each electric vehicle continues charging or discharging at the command value until the contract period ends or the power request value is changed. When the contract period ends, each electric vehicle stops charging or discharging the power storage device and receives an incentive from the system 300.

[0023] 2 ends when the process of S14 is executed. However, when the power request value requested by the market system is changed, a market request signal, a first request signal, and a second request signal notifying the new power request value are sent to the systems 100, 200, and 300, respectively. Then, when the system 300 receives this second request signal, it executes the above process flow (S11 to S14) again based on the new power request value.

[0024] FIG. 3 is a diagram illustrating the required charge / discharge amount in three cases (examples). In case 1, as shown by line L51, the required power value is not changed during the contract period. In this case, the required charge / discharge amount is the product of the contract amount Y and the remaining time (the time remaining until the end of the contract period) (hereinafter referred to as the "basic required amount"). As shown by line L52, the required charge / discharge amount decreases as the remaining time shortens. In case 2, as shown by line L61, the required power value is changed from the contract amount Y to a decreasing value at time t10. In this case, as shown by line L62, the required charge / discharge amount changes according to the formula "required charge / discharge amount = basic required amount - (contract amount Y - current upper level instruction) x allowed time when the required power value is changed." In case 3, as shown by line L71, the required power value is changed from the contract amount Y to a decreasing value at time t21, and then returns to the contract amount Y at time t22. In this case, the required charge / discharge amount changes according to the above formula, as shown by line L72.

[0025] Times t0 to t3 shown in FIG. 2 are the same as times t0 to t3 in FIG. 1. Line L10A shows the transition of the power request value that the second request signal requests of the electric vehicle resource. Lines L11A and L12A show the lower and upper limits, respectively, of the allowable range set for the power request value (line L10A). System 300 determines the power command value for the electric vehicle resource in accordance with equations (1) to (3) in FIG. 2. When the available charge / discharge amount is small, the power command value for the electric vehicle resource is determined as shown by line L21. When the available charge / discharge amount is small at time t0, system 300 determines power command value Y1 in S13, and then transmits a control command to each electric vehicle in S14 so that the power value of the electric vehicle resource reaches power command value Y1 at time t1. On the other hand, when the available charge / discharge amount is large, the power command value for the electric vehicle resource is determined as shown by line L22. If the possible charge / discharge amount at time t0 is large, system 300 determines a power command value Y2 in S13, and then transmits a control command to each electric vehicle in S14 so that the power value of the electric vehicle resource reaches power command value Y2 at time t1. Line L21 is closer to line L11A than line L10A. Line L22 is closer to line L12A than line L10A. The smaller the estimated possible charge / discharge amount, the smaller the charging power or discharging power of the electric vehicle resource becomes within the allowable range.

[0026] As described above, the power management system according to this embodiment includes an EM resource and a control device that controls the EM resource. Specifically, the system 300 controls the electric vehicle resource. The electric vehicle resource (vehicles 10, 20) includes a power storage device and is configured to perform energy management by at least one of charging and discharging the power storage device. When the system 300 (control device) receives a request signal (second request signal) requesting energy management, the system 300 estimates an adjustable amount, which is the amount of power that the electric vehicle resource can adjust (S11), and causes the electric vehicle resource to perform the energy management requested by the request signal during a predetermined EM period (e.g., a contract period) (S14). The request signal indicates a power request value for energy management (see line L10A). The system 300 determines a power command value for the electric vehicle resource such that, during the EM period, the smaller the estimated adjustable amount is, the smaller the charging or discharging power of the resource is within a tolerance range set for the power request value (S13). This power management system makes it easier for the resource to perform the energy management requested during the EM period. Energy management can then be used to stabilize the power system (for example, the power grid PG).

[0027] More specifically, the above-described power management system recognizes that the requested EM (energy management) has been executed (the resource has successfully executed EM) if the charging or discharging power provided by the resource during the EM period does not match the power request value (target value) as long as it is within a tolerance range set for the power request value. The tolerance range determines the EM required for the power system. The narrower the tolerance range, the higher the accuracy of the EM. Furthermore, the wider the tolerance range, the easier it is to secure resources for EM.

[0028] Furthermore, in the above-described power management system, a power command value for a resource is determined according to the resource's state. Specifically, the smaller the adjustable amount of the resource during the EM period, the smaller the power command value for the resource is determined to reduce the charging or discharging power of the resource within the allowable range. When the adjustable amount of the resource is small, by bringing the power command value for the resource closer to the lower limit of the allowable range, the adjustable amount of the resource during the EM period is prevented from falling below the amount required for adjustment. Furthermore, when the adjustable amount of the resource is large, by bringing the power command value for the resource closer to the upper limit of the allowable range, power adjustment (energy management) to the requesting side is strengthened, which contributes to the stabilization of the power system.

[0029] Alternatively, a TSO (system operator) may request energy management instead of the electricity market. Each of the systems 100, 200, and 300 is implemented as an on-premise server, but may also be implemented on the cloud. The functions of each system may be implemented in a single device.

[0030] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0031] 10,20 Vehicles, 100 Supply and demand management system, 200 Resource management system, 300 Electric vehicle management system, 510,520 Power supply equipment, PG power system.

Claims

[Claim 1] a resource having a power storage device and configured to be able to perform energy management by at least one of charging and discharging the power storage device; a control device that controls the resources; A power management system comprising: the control device is configured, when receiving a request signal requesting energy management, to estimate an adjustable amount, which is an amount of power that the resource can adjust, and to cause the resource to perform the energy management requested by the request signal for a predetermined period of time; the request signal indicates a power request value for the energy management; The control device is configured to determine a power command value for the resource so that the smaller the estimated adjustable amount is during the specified period, the smaller the charging power or discharging power by the resource becomes within an acceptable range set for the power requirement value.

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