Power management system and power management method

Abstract

To reduce a user burden in a case where selling / buying of power occurs in a power adjustment resource.SOLUTION: A power management system 500 comprises: a HEMS controller 15 which controls a corresponding HEMS 10 in a plurality of power adjustment resources; and an energy management server 2 which sets power management control due to the HEMS controller 15. The power management control includes: plan control in which the HEMS controller 15 is commanded to control the HEMS 10 on the basis of a predetermined power demand / supply plan; and edge control in which the HEMS controller 15 is commanded to control the HEMS 10 based on actual situations of surplus power and demand / supply power of the HEMS 10. The energy management server 2 commands the edge control to the HEMS controller 15 during a period in which occurrence of at least one of selling of surplus power and buying of demand / supply power is predicted in the HEMS 10 during execution of the plan control.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a power management system and a power management method, and more particularly, to a system and method for managing power supply and demand in a power grid including a plurality of power adjustment resources.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2016-187254 (Patent Document 1) discloses a method for controlling a storage battery with low power loss of power generated using renewable energy, and a method for controlling a water heater that can be controlled so as not to fall below a minimum required power value. Patent Document 1 also describes calculating a prediction error of prediction data using operation plan data and actual operation result data of a storage battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a power grid including a plurality of power adjustment resources (for example, a home energy management system described later), not only when the actual power supply and demand of a certain resource changes along with the power supply and demand plan, but also when power trading occurs in the resource, that is, when selling surplus power and / or buying required power (deficient power). When such power trading occurs, it is desirable to reduce the burden on the user of the resource.

[0005] The present disclosure has been made to solve the above problems, and one of the objects of the present disclosure is to reduce the user burden when power trading occurs in a power adjustment resource.

Means for Solving the Problems

[0006] A power management system relating to a certain aspect of this disclosure manages power supply and demand in a power grid that includes multiple power adjustment resources. The power management system comprises a controller that controls corresponding power adjustment resources among the multiple power adjustment resources, and a server that configures power management control by the controller for the corresponding resources. Power management control includes a first control that instructs the controller to control the corresponding resources based on a predetermined power supply and demand plan, and a second control that instructs the controller to control the corresponding resources based on the actual situation of surplus power and demand power in the corresponding resources. During the execution of the first control, the server instructs the controller to perform the second control during a period in which at least one of the sale of surplus power and the purchase of demand power is expected to occur in the corresponding resources.

[0007] A power management method relating to another aspect of this disclosure manages power supply and demand in a power grid that includes multiple power adjustment resources. The power management method includes the step of a server setting power management control for a corresponding power adjustment resource, which is one of the multiple power adjustment resources, to a controller. The power management control includes a first control, which is a command from the server to the controller to control the corresponding resource based on a pre-formulated power supply and demand plan, and a second control, which is a command from the server to the controller to control the corresponding resource based on the actual situation of surplus power and demand power in the corresponding resource. The setting step includes predicting whether at least one of selling surplus power and buying demand power will occur in the corresponding resource while the first control is being executed, and switching the power management control from the first control to the second control during the period in which at least one of selling surplus power and buying demand power is predicted to occur. [Effects of the Invention]

[0008] According to this disclosure, the burden on users when electricity is bought and sold in power adjustment resources can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an example of the overall configuration of a power management system according to an embodiment of the present disclosure. [Figure 2] This is a time chart illustrating the overview of power management control in this embodiment. [Figure 3] This flowchart shows an example of the power management control processing procedure in this embodiment. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated.

[0011] [Embodiment] <System Configuration> Figure 1 shows an example of the overall configuration of a power management system according to an embodiment of the present disclosure. The power management system 500 comprises a CEMS 1 and an energy management server 2.

[0012] CEMS1 stands for Community Energy Management System or City Energy Management System. CEMS1 includes, for example, multiple Home Energy Management Systems (HEMS) 10. In CEMS1, a microgrid MG is constructed by multiple HEMS 10. The microgrid MG is connected to the power grid 9 in a way that allows for the exchange of power with the power grid 9. The power grid 9 is a power network constructed by power plants and transmission and distribution facilities.

[0013] Note that the microgrid MG is an example of a "power grid" as described in this disclosure. CEM1 may include a Factory Energy Management System (FEMS) or a Building Energy Management System (BEMS) in place of or in addition to HEMS10. CEM1 may include only one of these energy management systems.

[0014] Each of the multiple HEMS 10 manages the electricity used in the home (electricity consumption, demand, and supply). Each HEMS 10 includes, for example, a water heater 11, an electric vehicle 12, a storage battery 13, a PV (photovoltaic) power generation system 14, and a HEMS controller 15.

[0015] The water heater 11 is, for example, a water heater in a cogeneration system (it may be a water heater that utilizes heat generated during self-generation, or it may be a heat pump water heater). The water heater 11 heats an optimal amount of hot water according to the amount of hot water used by each household at night using inexpensive off-peak electricity, and stores the heated water in a storage tank in preparation for use the next day (so-called reheating).

[0016] The electric vehicle 12 is a vehicle including a battery (not shown), specifically a plug-in hybrid electric vehicle (PHEV), a battery electric vehicle (BEV), etc. The electric vehicle 12 is configured to receive power from a microgrid MG by connecting a charging cable extending from a charging facility (not shown) to an inlet (not shown) of the electric vehicle 12 (external charging). The electric vehicle 12 may also be configured to discharge to a microgrid MG by connecting a charging cable to an outlet (not shown) of the electric vehicle 12 (external discharge). In this way, the electric vehicle 12 also functions as a mobile energy storage device.

[0017] The storage battery 13 is a stationary energy storage device that stores the electric power generated during the day by the PV power generation facility 14. The storage battery 13 is a secondary battery such as a lithium-ion battery or a nickel-metal hydride battery, and may be manufactured using, for example, a traction battery that was previously installed in a vehicle.

[0018] The PV power generation facility 14 generates electricity by receiving sunlight during the day, and charges the storage battery 13 or outputs the generated electricity to the microgrid MG. The HEMS 1 may include other natural variable power sources (power generation facilities whose power generation output varies depending on weather conditions), such as wind power generation facilities, instead of or in addition to the PV power generation facility 14.

[0019] The above devices are merely examples, and the HEMS 10 may further include the above-described devices other than those shown (electrical devices or V2H devices such as air conditioners, fuel cells, lighting devices, generators, heat storage tanks, etc.). Each device within the HEMS 10 corresponds to the "power adjustment resource" according to the present disclosure.

[0020] The HEMS controller 15 is configured to be communicable with each device within the HEMS 1. The HEMS controller 15 acquires information on each device and controls the operation of each device.

[0021] The HEMS controller 15 is configured to communicate bidirectionally with the energy management server 2 as well. The HEMS controller 15 transmits values (such as power values and status values) indicating the operation status of each device acquired from each device to the energy management server 2. Further, the HEMS controller 15 controls each device according to a control command from the energy management server 2.

[0022] The energy management server 2 is a higher-level computer (cloud server) that comprehensively manages a plurality of HEMS controllers 15. The energy management server 2 includes a processor 201, a memory 202, and a communication interface 203. The processor 201 reads out programs and various data (maps, relational expressions, parameters, etc.) stored in the memory 202 and expands them in the memory 202 to execute various processes. The communication interface 203 is configured to communicate with each of the plurality of HEMS controllers 15. The energy management server 2 executes "power management control" for each of the plurality of HEMs 10 to manage charging, power consumption, and / or discharging within that HEMS 10. This control will be described later.

[0023] Each of the plurality of HEMS controllers 15 corresponds to the "controller" according to the present disclosure. The energy management server 2 corresponds to the "server" according to the present disclosure.

[0024] <Power management control> For each HEMS 10 that is a consumer in CEM1, the energy management server 2 formulates a power supply and demand plan so that the electricity bill of that HEMS 10 is minimized based on the electricity rate unit price and the predicted receiving-end power of that HEMS 10. Then, the energy management server 2 executes "planned control" according to the power supply and demand plan for each HEMS 10. In planned control, the control authority of each device within the HEMS 10 is held by the energy management server 2, and the energy management server 2 controls each device within the HEMS 10 in a coordinated manner. Thereby, self-consumption within the HEMS 10 can be maximized and the electricity bill can be suppressed (minimized).

[0025] However, the actual power supply and demand of HEMS10 does not necessarily follow the power supply and demand plan, thus preventing the suppression of electricity charges. A consumer's behavior on one day may differ from that of a consumer on another day (normal behavior patterns). Alternatively, weather may change moment by moment, or weather may cause changes that differ from those predicted based on past data. As a result, the amount of electricity generated by natural variable power sources such as PV power generation equipment 14 may differ from the prediction. In addition, it is difficult to formulate a precise power supply and demand plan with a short time granularity (for example, in one-minute increments). Therefore, there is a possibility that electricity will be bought and sold in HEMS10, that is, there may be periods when surplus electricity from HEMS10 is sold, or periods when electricity demand (shortage) from HEMS10 is purchased. When such periods occur, the amount of electricity purchased and / or sold will increase compared to when the actual power supply and demand always follows the power supply and demand plan, and electricity charges may increase accordingly.

[0026] Therefore, in this embodiment, during the execution of planned control, during periods when it is predicted that electricity will be bought or sold, in this example, when it is predicted that surplus electricity will be sold by the PV power generation equipment 14 or that electricity will be purchased due to increased electricity demand from equipment (air conditioning equipment, lighting equipment, etc.) within the HEMS 10, the energy management server 2 switches the power management control from "planned control" to "edge control".

[0027] In edge control, control rights for each device within HEMS 10 are transferred from the energy management server 2 to the HEMS controller 15. The HEMS controller 15 monitors the power supply at the receiving end of HEMS 10. The HEMS controller 15 then meticulously controls the charging and discharging of each device within HEMS 10 (in this example, the water heater 11, the electric vehicle 12, and the storage battery 13) in response to changes in the amount of electricity bought and sold at the receiving end of HEMS 10. This reduces the amount of electricity bought and sold at the receiving end of HEMS 10 and maximizes self-consumption. As a result, it becomes possible to reduce electricity costs in HEMS 10.

[0028] The following provides a more detailed explanation of the switching between planned control and edge control. Planned control corresponds to the "first control" in this disclosure, and edge control corresponds to the "second control" in this disclosure.

[0029] <Switching between planned control and edge control> Figure 2 is a time chart illustrating the overview of power management control in this embodiment. The horizontal axis represents elapsed time. More specifically, the horizontal axis represents elapsed time during a specific target period (in this example, the period from 0:00 to 24:00 the following day). The vertical axis represents power (generated power or demanded power). In Figure 2, from top to bottom, the power forecast for the following day, the operation plan for the water heater 11, the operation plan for the electric vehicle 12, the operation plan for the storage battery 13, and the type of power management control are shown for the target HEMS 10.

[0030] The energy management server 2 predicts the power supply at the receiving end for the target HEMS 10 during the target period at predetermined timings. In this example, the prediction is made at midnight, and it is assumed that a surplus power supply will occur between 8:00 and 15:00, and a demand power supply (i.e., a power shortage) will occur between 17:00 and 22:00. It is also assumed that inexpensive off-peak electricity can be used during the period from nighttime until 7:00.

[0031] It is predicted that neither surplus nor demanded power will be generated during the period from 0:00 to 8:00. Therefore, the energy management server 2 will execute planned control. Consequently, the energy management server 2 will retain control of each device within the HEMS 10 during this period.

[0032] During the period up to 7:00am, the energy management server 2 uses inexpensive off-peak electricity to perform the following controls. First, the energy management server 2 determines the time for the water heater 11 to heat water. In this example, in order to heat the optimal amount of water by 5:00pm, when demand for electricity is predicted, the energy management server 2 controls the water heater 11 to heat at least a portion of the optimal amount of water using off-peak electricity. Second, the energy management server 2 charges the electric vehicle 12 so that its State of Charge (SOC) reaches a target value at the scheduled departure time of the electric vehicle 12. In this example, in order for the SOC to reach the target SOC (e.g., SOC=80%) at 12:00pm, the scheduled departure time, the energy management server 2 charges the electric vehicle 12 to at least an intermediate SOC (e.g., SOC=60%) using off-peak electricity. Third, the energy management server 2 charges the battery 13 using off-peak electricity.

[0033] It is predicted that surplus power will be generated between 8:00 AM and 3:00 PM. Consequently, there is a high probability that the power receiving end of HEMS 10 will sell the excess power. Therefore, the energy management server 2 will switch power management control from planned control to edge control. Accordingly, during this period, control rights for each device within HEMS 10 will be transferred from the energy management server 2 to the HEMS controller 15.

[0034] The HEMS controller 15 controls the actual power consumption of HEMS 10 (the charging power or total power consumption of each device) to reduce the amount of electricity sold at the receiving end of HEMS 10, so that it is within the range of surplus power and as close to surplus power as possible. In this example, first, the HEMS controller 15 charges the electric vehicle 12 with power equivalent to the remaining SOC from the SOC where charging was stopped midway to the final SOC (for example, the remaining 20% ​​from 60% to 80%) so that the SOC of the electric vehicle 12 reaches the target SOC by the scheduled departure time of the electric vehicle 12. The HEMS controller 15 also controls the water heater 11 to heat the remaining hot water (the difference between the optimal amount of hot water and some of the hot water heated using off-peak electricity) using off-peak electricity so that the optimal amount of hot water is heated by 17:00 when demand for electricity arises. Furthermore, the HEMS controller 15 charges the storage battery 13 with the surplus power that cannot be charged or consumed by the water heater 11 and the electric vehicle 12 (the surplus power minus the power consumed by the water heater 11 and the power used to charge the electric vehicle 12).

[0035] It is predicted that neither surplus nor demanded power will be generated during the period from 3 PM to 5 PM. Therefore, the energy management server 2 will switch the power management control back from edge control to planned control. Consequently, the energy management server 2 will regain control of each device within the HEMS 10 from the HEMS controller 15.

[0036] It is predicted that power demand will occur between 5 PM and 10 PM. Consequently, it is highly likely that electricity will be purchased at the power receiving end of HEMS 10. Therefore, the energy management server 2 will switch power management control back from planned control to edge control. Consequently, during this period, control rights for each device within HEMS 10 will be transferred again from the energy management server 2 to the HEMS controller 15.

[0037] The HEMS controller 15 controls the actual power supplied by the HEMS 10 (the sum of the discharged power from each device) so as to be within the range of the demand power and as close as possible to the demand power, in order to reduce the amount of electricity purchased at the receiving end of the HEMS 10. In this example, the HEMS controller 15 discharges the storage battery 13. Although not shown in the diagram, if the electric vehicle 12 has returned from being away, the HEMS controller 15 may also discharge the electric vehicle 12.

[0038] It is predicted that neither surplus nor demanded power will be generated during the period from 10 PM to midnight. Therefore, the energy management server 2 will switch the power management control back from edge control to planned control. Consequently, the energy management server 2 will regain control of each device within the HEMS 10 from the HEMS controller 15.

[0039] Thus, in this embodiment, during periods when it is predicted that surplus power will be sold or demanded power will be purchased in the HEMS 10, the power management control for the HEMS 10 is switched from planned control to edge control. As a result, control rights for each device within the HEMS 10 are delegated to the HEMS controller 15. This allows the HEMS controller 15 to control each device within the HEMS 10 while monitoring the actual power at the receiving end of the HEMS 10 in real time. In other words, the HEMS controller 15 can control the power (charging power, power consumption, and / or discharge power) of each device within the HEMS 10 in short time units in response to changes in the power at the receiving end of the HEMS 10. Therefore, according to this embodiment, the self-consumption of the HEMS 10 can be maximized, thereby reducing the amount of electricity bought and sold at the receiving end of the HEMS 10. As a result, electricity costs for the HEMS 10 can be reduced.

[0040] <Processing Flow> Figure 3 is a flowchart showing an example of the power management control processing procedure in this embodiment. The processing shown in this flowchart is executed during the execution of planned control when predetermined conditions are met (for example, at predetermined intervals). Each step is implemented by software processing by the energy management server 2, but may also be implemented by hardware (electrical circuits) located within the energy management server 2. Hereinafter, each step will be abbreviated as S.

[0041] In S1, the energy management server 2 determines whether a trigger (hereinafter referred to as "update trigger") has occurred to update the power supply and demand plan of the target HEMS 10. For example, an update trigger may occur when a predetermined time arrives. Alternatively, an update trigger may occur in accordance with an operation by the user of the HEMS 10, or in accordance with an operation by the administrator of the energy management server 2. If an update trigger occurs (YES in S1), the energy management server 2 updates the power supply and demand plan of the target HEMS 10 (S2). In other words, the control content of the plan control to maximize self-consumption within the HEMS 10 and minimize electricity costs is updated. After that, the energy management server 2 proceeds to S3. If an update trigger has not occurred (NO in S1), the process in S2 is skipped and the process proceeds to S3.

[0042] In S3, the energy management server 2 determines whether a trigger (hereinafter referred to as "determination trigger") has occurred for the target HEMS 10 to determine whether or not electricity is being bought or sold. The determination trigger may occur periodically, for example, when a predetermined time arrives. Alternatively, the determination trigger may occur each time an update trigger occurs (i.e., each time the power supply and demand plan is updated).

[0043] If a determination trigger occurs (YES in S3), the energy management server 2 determines whether it is predicted that at least one of the following will occur during the target period: selling surplus electricity and buying electricity to meet demand (S4). The energy management server 2 determines, for example, whether there will be a period in which the power generated by the PV power generation equipment 14 increases and exceeds the power that can be consumed or stored in the HEMS 10, or whether there will be a period in which the power generated by the PV power generation equipment 14 is insufficient to meet the power requirements in the HEMS 10, based on the latest status of the equipment in the HEMS 10 (for example, changes in the energy storage status of the water heater 11, electric vehicle 12, and storage battery 13), the latest actions of the consumer (for example, increases or decreases in the power consumption of various electrical appliances), and the latest weather information (especially solar radiation).

[0044] If it is predicted that there will be no period during the target period during which surplus electricity will be sold or demanded electricity will be sold (NO in S5), the energy management server 2 sets the power management control to planned control for the entire target period (S6). In this case, the energy management server 2 retains control rights of the HEMS 10 for the entire period.

[0045] In contrast, if it is predicted that surplus electricity will be sold or demanded electricity will be purchased at some point during the target period (YES in S5), the energy management server 2 sets the power management control to edge control for the period during which the sale of surplus electricity and / or the purchase of demanded electricity is predicted (S7). As a result, when that period arrives, control of HEMS 10 is transferred from the energy management server 2 to the HEMS controller 15. Power management control for periods other than those mentioned above is set to planned control. As a result, when a period other than those mentioned above arrives, control of HEMS 10 is returned from the HEMS controller 15 to the energy management server 2. Note that during the execution of edge control, the energy management server 2 may return the power management control of HEMS 10 to planned control during periods when it is predicted that neither the sale of surplus electricity nor the purchase of demanded electricity will occur.

[0046] As described above, in this embodiment, during periods when it is predicted that surplus power will be sold and / or demanded power will be purchased in the HEMS 10, the power management control is set to edge control, and the control rights of each device in the HEMS 10 are delegated to the HEMS controller 15. This allows the HEMS controller 15 to control each device while monitoring the power at the receiving end of the HEMS 10 in real time. By the HEMS controller 15 precisely controlling the power of each device in response to changes in the power at the receiving end of the HEMS 10, the self-consumption of the HEMS 10 can be maximized. This reduces the amount of electricity bought and sold at the receiving end of the HEMS 10. In addition, if edge control is always set, the charging and discharging of devices in the HEMS 10 may be switched frequently. By executing edge control only during periods when it is predicted that surplus power will be sold and / or demanded power will be purchased, power losses associated with such switching can be suppressed. Therefore, according to this embodiment, electricity costs in the HEMS 10 can be reduced, and the burden on the HEMS 10 user can be reduced.

[0047] Figure 2 illustrates that the water heater 11, electric vehicle 12, and storage battery 13 are the controlled devices for switching between planned control and edge control. Controlling the water heater 11 to heat the optimal amount of water using inexpensive off-peak electricity offers particularly significant benefits for self-consumption. Therefore, the water heater 11 has the highest priority as a controlled device. The electric vehicle 12 cannot be freely charged and discharged because it has a set departure time and needs to be charged to avoid running out of power while away from home. Although conditions are imposed on charging and discharging to avoid reducing user convenience, the battery capacity of the electric vehicle 12 is sufficiently large, making it a significant contributor to self-consumption. The storage battery 13 often has an even larger battery capacity than the electric vehicle 12. In addition, the storage battery 13 offers high control flexibility without reducing user convenience. The controlled devices are not limited to the three types of devices described above and may include, for example, fuel cells.

[0048] Furthermore, air conditioning and lighting systems are not suitable as controlled devices. This is because if the indoor temperature or brightness is controlled against user input, user comfort may be compromised. Also, PV power generation equipment 14 is not suitable as a controlled device. This is because controlling PV power generation equipment 14 to reduce power generation may result in economic disadvantages for the user (reduction in electricity sales revenue).

[0049] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0050] 1 CEMS, 10 HEMS, 11 water heaters, 12 electric vehicles, 13 storage batteries, 14 PV power generation equipment, 15 HEMS controllers, 2 management servers, 201 processors, 202 memory, 203 communication interfaces, 500 power management systems, 9 power grids.

Claims

1. A power management system for managing power supply and demand in a power grid that includes multiple power adjustment resources, A controller that controls a corresponding power adjustment resource among the multiple power adjustment resources, The system includes a server which sets power management control by the controller for the corresponding resource, The aforementioned power management control is A first control that commands the controller to control the corresponding resources based on a pre-formulated power supply and demand plan, This includes a second control that commands the controller to control the corresponding resource based on the actual conditions of surplus power and demand power in the corresponding resource, The aforementioned server, During the execution of the first control, if at least one of the following is expected to occur in the corresponding resource, the controller is instructed to perform the second control: During the execution of the second control, if it is predicted that neither the sale of surplus electricity nor the purchase of demanded electricity will occur, the controller is instructed to perform the first control. In the first control, while retaining control rights to the corresponding resource, The second control is a power management system that delegates the control rights to the controller.

2. Each of the aforementioned power adjustment resources belongs to either the first or second group, The first group includes at least one of a water heater, an electric vehicle, a storage battery, and a fuel cell. The second group includes at least one of an air conditioning system, a lighting system, and a solar power generation system. The aforementioned server, Of the plurality of power adjustment resources, the power adjustment resources belonging to the first group are the targets of the first control and the second control, The power management system according to claim 1, wherein power adjustment resources belonging to the second group among the plurality of power adjustment resources are not subject to control.

3. A power management method for managing power supply and demand in a power grid that includes multiple power adjustment resources, The server includes the step of setting power management control for the corresponding resource, which is one of the multiple power adjustment resources, to the controller. The aforementioned power management control is A first control involves the server issuing a command to the controller to control the corresponding resources based on a pre-formulated power supply and demand plan, This includes a second control that commands the controller from the server to control the corresponding resource based on the actual situation of surplus power and demand power in the corresponding resource, The aforementioned setting step is, During the execution of the first control, the step of predicting whether at least one of selling surplus electricity and buying demanded electricity will occur in the corresponding resource, During a period in which the sale of surplus electricity and the purchase of electricity in demand are expected to occur, the power management control is switched from the first control to the second control, During the execution of the second control, if it is predicted that neither the sale of surplus power nor the purchase of demanded power will occur, the power management control is switched from the second control to the first control. A power management method comprising the steps of: in the first control, the server retains control rights over the corresponding resource; and in the second control, the server delegates the control rights to the controller.

Images