Power System

Abstract

To suppress simultaneous generation of inrush current or starting current in a plurality of houses that share a distribution transformer, and to suppress an increase in voltage drop.SOLUTION: A server 200 receives requests to start up electrical appliances installed in respective houses 10 in a distribution block DB that shares a distribution transformer 5, arbitrates startup timing of the electrical appliances installed in the respective houses 10, and thereby prevents inrush current from occurring at the same time.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to power systems. [Background technology]

[0002] JP 2018-107981 A (Patent Document 1) discloses a power distribution system that can reduce the current (current) flowing through a power distribution line, reduce costs, and provide a stable power supply. In this power distribution system, a power interchange block is formed from a number of detached houses and a shared storage battery connected via a power distribution line to a pole-mounted transformer that steps down the power of the power grid (power system). The charging and discharging of the shared storage battery and the like are controlled so that the power state of the power distribution line in the power interchange block remains within a specified state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-107981 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the power state of the distribution line in the power interchange block is kept within a predetermined state by controlling the charge / discharge amount of the shared storage battery etc. so that the current value flowing through the distribution line is equal to or less than a predetermined value. Various electrical devices (electrical loads) are installed in the houses. Some of these electrical loads are capacitive loads and inductive loads, and when the power is turned on to these electrical loads (when the electrical loads start up), an inrush current or starting current is generated. The inrush current or starting current can be ten or so times the steady-state current, causing a voltage drop.

[0005] In particular, if an inrush current or starting current occurs simultaneously among multiple homes that share a distribution transformer (pole transformer), it may cause a large voltage drop and have a significant impact on the power grid. In addition, the current flowing through the distribution transformer and distribution lines will become very large, requiring equipment with a large allowable current value. Patent Document 1 does not mention these issues caused by inrush current, etc.

[0006] The objective of the present disclosure is to prevent inrush current or starting current from occurring simultaneously in multiple homes that share a distribution transformer, prevent large voltage drops, and prevent the current flowing through the distribution transformer and distribution lines from becoming extremely large. [Means for solving the problem]

[0007] The power system according to the present disclosure includes a plurality of homes connected to a distribution transformer that transforms power from a power grid, electrical loads installed in the homes, and a server capable of receiving information about the electrical loads. The electrical loads installed in the homes are configured to transmit start-up requests that request start-up accompanied by an inrush current or starting current equal to or greater than a predetermined value, and to start up based on a start-up permission command in response to the start-up requests. When the server simultaneously receives start-up requests from the electrical loads installed in the plurality of homes, the server is configured to arbitrate the start-up timing of the electrical loads and transmit a start-up permission command when a parameter related to a voltage drop caused by the inrush current or starting current is equal to or greater than a permissible value.

[0008] According to this configuration, a plurality of houses are connected to a distribution transformer and share the distribution transformer. The electric loads installed in the houses are configured to transmit start-up requests that request start-up accompanied by an inrush current or starting current equal to or greater than a predetermined value, and to start up based on a start-up permission command in response to the start-up request. When a server capable of receiving information related to the electric loads receives start-up requests simultaneously from the electric loads installed in the plurality of houses, if a parameter related to a voltage drop caused by the inrush current or starting current is equal to or greater than a permissible value, the server arbitrates the start-up timing of the electric loads and transmits a start-up permission command.

[0009] When the server receives simultaneous start-up requests from electrical loads installed in multiple homes, if a parameter related to voltage drop caused by inrush current or starting current is above an allowable value, the server arbitrates the start-up timing of the electrical loads, thereby preventing electrical loads installed in multiple homes from starting up simultaneously and preventing the occurrence of simultaneous inrush current or starting current.

[0010] Preferably, the parameter relating to the voltage drop may be a power fluctuation amount due to an inrush current or a starting current. The server may be configured to calculate a power fluctuation amount for each electric load, add up the power fluctuation amounts of the electric loads that have simultaneously issued a start request to calculate a total power fluctuation amount, and, when the total power fluctuation amount is equal to or greater than a tolerance value, arbitrate the start timing of the electric loads and transmit a start permission command.

[0011] According to this configuration, the voltage drop due to the inrush current or starting current is estimated based on the amount of power fluctuation due to the inrush current or starting current. The allowable level of voltage fluctuation in a power grid (electric power system) is often determined by the magnitude of the amount of power fluctuation or the magnitude of frequency change. With this configuration, the amount of power fluctuation due to the inrush current or starting current is used to arbitrate the start-up timing of the electrical load, so that the impact on the power grid can be effectively suppressed.

[0012] Preferably, each of the houses may include a controller capable of controlling a plurality of electric loads installed in the house, the controller being configured to be able to communicate with a server, the controller transmitting a start-up request to the server and starting up the electric loads based on a start-up permission command received from the server.

[0013] According to this configuration, a controller capable of controlling multiple electrical loads installed in a home can send a start-up request to a server and start the electrical loads, making it possible to arbitrate the start-up timing of each electrical load even if there is no configuration capable of communication between each electrical load and the server.

[0014] Preferably, the electric load may further include a configuration for transmitting a stop request to request the electric load to stop operation, and for stopping the operation based on a stop permission command in response to the stop request. When the server receives stop requests simultaneously from the electric loads installed in a plurality of houses, and when a parameter related to a voltage rise accompanying the operation stop is equal to or greater than a threshold value, the server is configured to arbitrate the stop timing of the electric load and transmit the stop permission command.

[0015] In multiple homes sharing a distribution transformer, if the operation of electrical loads stops at the same time, power consumption may drop suddenly and a momentary voltage rise may occur. According to this configuration, the electrical loads installed in the homes are configured to transmit a stop request to request that they stop operation, and to stop operation based on a stop permission command in response to the stop request. When the server receives stop requests simultaneously from the electrical loads installed in multiple homes, if a parameter related to a voltage rise due to the operation stop is equal to or greater than a threshold, it arbitrates the timing of stopping the electrical loads and transmits a stop permission command.

[0016] When the server receives simultaneous shutdown requests from electrical loads installed in multiple homes, if a parameter related to the voltage rise associated with shutdown is above a threshold value, it arbitrates the timing of shutdown of the electrical loads, thereby preventing electrical loads installed in multiple homes from shutting down simultaneously and suppressing momentary voltage rises.

[0017] Preferably, the parameter related to the voltage rise may be a power fluctuation amount due to the stop of operation. The server obtains the power fluctuation amount for each electric load, and calculates a total power fluctuation amount by adding up the power fluctuation amounts of the electric loads that have simultaneously issued a stop request, and when the total power fluctuation amount is equal to or greater than a threshold, arbitrates the stop timing of the electric loads and transmits a stop permission command.

[0018] The allowable level of voltage fluctuation in a power grid (electrical power system) is often determined by the magnitude of the power fluctuation or the magnitude of the frequency change. With this configuration, the voltage rise caused by the stop of operation of an electric load is estimated from the power fluctuation, and the timing of stopping the electric load is adjusted, so that the impact on the power grid can be effectively suppressed.

[0019] Preferably, each of the houses may include a controller capable of controlling a plurality of electric loads installed in the house, the controller being configured to be able to communicate with a server, the controller transmitting a stop request to the server and stopping the operation of the electric loads based on a stop permission command received from the server.

[0020] According to this configuration, a controller capable of controlling multiple electrical loads installed in a home can send a stop request to a server and stop the operation of the electrical loads, making it possible to arbitrate the stop times of each electrical load even if there is no configuration capable of communication between each electrical load and the server. Effect of the Invention

[0021] According to the present disclosure, in multiple homes that share a distribution transformer, the occurrence of inrush current or starting current at the same time can be prevented, and voltage drops can be suppressed. [Brief description of the drawings]

[0022] [Figure 1] 1 is a diagram illustrating an overall configuration of a power system according to an embodiment of the present invention. [Diagram 2] 1 is a diagram showing a schematic configuration of a house according to an embodiment of the present invention; [Diagram 3] 13 is a flowchart showing an example of a process executed by the server 200. [Figure 4] 13 is a flowchart showing an example of a process executed by the server 200 in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference characters, and the description thereof will not be repeated.

[0024] Fig. 1 is a diagram showing an overall configuration of a power system according to the present embodiment. As shown in Fig. 1, the power system 100 includes a power grid (power system) 1, a distribution substation 3, a distribution transformer (pole transformer) 5, a house 10, a shared battery 20, and a server 200.

[0025] Power grid 1 is a power system consisting of power plants, transmission lines, high-voltage substations, etc., and is a power grid managed by an electricity retailer, etc. Power from a transmission line 2 of power grid 1 is stepped down by a distribution substation 3 to a voltage of, for example, 6.6 kV, and transmitted to a distribution line 4. The power from distribution line 4 is stepped down by a distribution transformer 5 to, for example, a single-phase three-wire 100 V / 200 V, and transmitted to a distribution line 6. Distribution transformer 5 may be, for example, a pole-mounted transformer with a capacity of 30 kVA.

[0026] The distribution line 6 is connected to a plurality of houses 10 via a service line 7 for each house. As a result, power transmitted from the distribution transformer 5 to the distribution line 6 is supplied to the plurality of houses 10. A shared battery 20 is also connected to the distribution line 6 via the service line 7. In this embodiment, five houses 10 and one shared battery 20 are connected to the power grid 1 via one distribution transformer 5. A low-voltage power system made up of the houses 10 (connected to the distribution transformer 5) and the shared battery 20 sharing one distribution transformer 5 is referred to as a distribution block DB.

[0027] 2 is a diagram showing a schematic configuration of a house according to this embodiment. A service line 7 connected to a distribution line 6 is connected to a domestic power line 8 via a smart meter 50. The smart meter 50 is an electronic power meter equipped with a communication function, which measures the amount of power exchanged between the power grid 1 and the house 10 during a predetermined measurement period (e.g., 30 minutes) and transmits the measured amount of power together with an identification code (ID) of the smart meter 50 to a server 300 under the jurisdiction of an electricity retailer at predetermined intervals (e.g., every 60 minutes).

[0028] In a house 10 connected to a power grid 1 via a smart meter 50, various electrical appliances such as a power conditioner (PCS) 12, a solar power generation device 13, a heat pump water heater 14, a refrigerator 15, an air conditioner (heating and cooling device) 16, and a charging and discharging device 17 are connected by using in-house power lines via a distribution board 11 compatible with a HEMS (Home Energy Management Service). This makes it possible to consume power supplied from the power grid 1, and to supply (reverse flow) power generated by the solar power generation device 13 and power discharged from an electric vehicle 40 to the power grid 1. Each of these electrical appliances corresponds to an "electrical load" in the present disclosure.

[0029] The charging / discharging facility 17 is a V2H (Vehicle to Home) charging / discharging facility that is capable of charging an electricity storage device of the electric vehicle 40 and of allowing electric power discharged from the electric vehicle 40 to flow reversely to the power grid 1.

[0030] The electric vehicle 40 is a Battery Electric Vehicle (BEV) equipped with a battery (electricity storage device) not shown. However, the type of the electric vehicle 40 may be any vehicle that can be connected to the charging / discharging facility 17, and may be a plug-in hybrid electric vehicle (PHEV) or a plug-in fuel cell electric vehicle (FCEV).

[0031] The house 10 is provided with a HEMS controller 30. The HEMS controller 30 is configured to be able to communicate with each electrical appliance such as a HEMS-compatible distribution board 11, a PCS 12, a refrigerator 15, and a heating and cooling device 16. The HEMS controller 30 acquires information about each electrical appliance and controls the operation of each electrical appliance.

[0032] The HEMS controller 30 is configured to be able to communicate with the server 200. The server 200 controls each electric appliance (electric load installed in the house 10) such as the refrigerator 15 and the air conditioner 16 via the HEMS controller 30. The server 200 includes a control device, a storage device, and a communication device, which are not shown, and the control device is configured to execute a predetermined calculation process. The storage device includes a memory that stores a program executed by the control device, and stores various information (maps, relational expressions, parameters, etc.) used in the program. The storage device includes a database, and stores the identification code (ID) of the HEMS controller 30 of each house 10, location value information of the ID, data related to each electric appliance, etc. The communication device includes a communication interface, and is configured to be able to communicate with the HEMS controller 30, the server 300, etc.

[0033] The shared battery 20 (see FIG. 1) temporarily stores the power generated by the solar power generation device 13 and supplies the stored power to each of the houses 10.

[0034] Each electrical device installed in the house 10 includes a capacitive load and an inductive load. For example, the refrigerator 15 and the air conditioner 16 include an electric compressor. When power is applied to start the electric compressor (electric motor), an inrush current or starting current is generated. The inrush current or starting current can be a large current that is ten or so times larger than the steady-state current. In the distribution block DB, if inrush currents occur simultaneously in the electrical devices installed in each of the houses 10, a large current equivalent to the sum of the inrush currents generated by the electrical devices of each of the houses 10 flows in the distribution transformer 5 shared by each of the houses 10 (connected to each of the houses 10), resulting in a large voltage drop.

[0035] To allow a large current equivalent to the sum of the inrush currents generated by the various electrical appliances in each residence 10 to flow, a distribution transformer 5 with a large allowable current value and a distribution line 6 with a large allowable current value would be required, increasing the cost of the equipment. Furthermore, allowing a large current equivalent to the sum of the inrush currents generated by the various electrical appliances in each residence 10 would result in a large voltage drop, and the impact on the power grid 1 could be significant.

[0036] In this embodiment, the start-up timing (start-up period) of various electric devices in each house 10 in the power distribution block DB is adjusted to prevent inrush currents from occurring simultaneously in the various electric devices installed in each house 10. This prevents a large voltage drop and prevents a large current from flowing through the distribution transformer 5 and the power distribution line 6 shared by each house 10.

[0037] In this embodiment, the HEMS controller 30 acquires information about each electric appliance and controls the operation of each electric appliance. Each electric appliance installed in the house 10 transmits a start request (ON request) to the HEMS controller 30 when a user turns on the power (when the switch of the electric appliance is turned ON). In addition, when starting an electric appliance that is currently stopped and has a large inrush current, the electric appliance also transmits a start request (ON request) to the HEMS controller 30. For example, when starting an electric compressor (electric motor) that has been stopped during operation of the refrigerator 15 or the air conditioner 16, the refrigerator 15 or the air conditioner 16 transmits a start request to the HEMS controller 30.

[0038] When the HEMS controller 30 receives the start request, it transmits "information (type, rated power consumption, etc.) of the electric device that transmitted the start request" and "identification code (ID) of the HEMS controller 30" as a start request signal to the server 200. When the server 200 receives start request signals from multiple HEMS controllers 30 simultaneously in the power distribution block DB, it arbitrates the start times (start timing) of the electric devices and transmits start permission commands to each HEMS controller 30 so that the start times of the electric devices do not overlap (so that the electric devices do not start at the same time). When the start request signal received from the HEMS controller 30 does not overlap with the start times of other electric devices (so that the electric devices do not start at the same time), the server 200 transmits the start permission command to the HEMS controller 30 (without arbitration). When the HEMS controller 30 receives the start permission command from the server 200, it controls the electric device that transmitted the start request based on the start permission command so that the electric device that transmitted the start request starts. In addition, for electrical appliances whose inrush current when powered on (switched ON) is smaller than a predetermined value and whose impact on the power grid 1 can be ignored even if an inrush current occurs at the same time, the appliance may be started without sending a start-up request (ON request) to the HEMS controller 30 and receiving a start-up permission command.

[0039] 3 is a flowchart showing an example of processing executed by the server 200. This flowchart is repeatedly processed at predetermined intervals by the server 200. This processing is executed by the server 200 for each power distribution block DB. First, in step (hereinafter, step is abbreviated as "S") 10, it is determined whether or not a start request signal has been received from the HEMS controller 30. If a start request signal has not been received from the HEMS controller 30, a negative determination is made and the current routine is terminated.

[0040] If the server 200 has received a start-up request signal from the HEMS controller 30, a positive determination is made and the process proceeds to S11. In S11, it is determined whether or not a plurality of start-up request signals have been received. If start-up request signals have been received from a plurality of HEMS controllers 30, it is determined that a plurality of start-up request signals have been received. If start-up request signals have been received from a plurality of HEMS controllers 30, a positive determination is made in S11 and the process proceeds to S12.

[0041] In S12, the server 200 calculates the total power fluctuation amount ΣΔkW. The server 200 calculates the power fluctuation amount ΔkW caused by the inrush current in each electrical device from the "information (type, rated power consumption, etc.) of the electrical device that transmitted the start request" and the "identification code (ID) of the HEMS controller 30" included in the start request signal received in S10. For example, the magnitude of the inrush current is calculated from the type and rated current consumption of the electrical device that transmitted the start request. At this time, the magnitude of the inrush current may be calculated by estimating the usage environment of the electrical device from the ID of the HEMS controller 30. For example, if the type of electrical device is a cooling / heating device 16, location information may be obtained from the ID of the HEMS controller 30 in addition to the rated power consumption of the cooling / heating device 16, and the magnitude of the inrush current may be calculated by taking into account the temperature at the location. Then, the server 200 calculates the power fluctuation amount ΔkW caused by the inrush current based on the magnitude of the inrush current.

[0042] The server 200 calculates the power fluctuation ΔkW due to the inrush current for each activation request signal received in S10 (for each ID of the HEMS controller 30), and calculates the total power fluctuation ΣΔkW by adding up all the calculated power fluctuations ΔkW.

[0043] In the next S13, it is determined whether the magnitude (absolute value) of the total power fluctuation amount ΣΔkW is equal to or greater than the tolerance value α. If the magnitude of the total power fluctuation amount ΣΔkW is equal to or greater than the tolerance value α (|ΣΔkW|≧α), a positive determination is made and the process proceeds to S14. The tolerance value α may be set in advance from a current value that is tolerable in the distribution transformer 5 and the distribution line 6, for example, or may be set based on a voltage drop that is tolerable in the power grid 1. In S13, if the magnitude of the total power fluctuation amount ΣΔkW is smaller than the tolerance value α (|ΣΔkW|<α), a negative determination is made and the process proceeds to S16.

[0044] In S14, the start-up time is arbitrated between the start-up request signals (between the IDs of the HEMS controllers 30) received in S10. In the present disclosure, the arbitration of the start-up time means transmitting a start-up permission command in which the start-up time (start-up timing) of each electric device is shifted so that each electric device is not started at the same time. For example, a start-up permission command is transmitted to the HEMS controller 30 so that the electric device with the largest power fluctuation amount ΔkW is started immediately. Then, after the electric device with the largest power fluctuation amount ΔkW is started, a start-up permission command is transmitted to the corresponding HEMS controller 30 in order of the magnitude of the power fluctuation amount ΔkW with an interval of several seconds so that each electric device is started in order. The method of arbitration of the start-up time is arbitrary. For example, a startup permission command may be sent to each HEMS controller 30 starting from the HEMS controller 30 with the lowest ID so that each electrical appliance is started with an interval of several seconds between each startup. Alternatively, a startup permission command may be sent to each HEMS controller 30 using a priority based on the type of electrical appliance so that each electrical appliance is started with an interval of several seconds between each startup.

[0045] The HEMS controller 30 that has received the start permission command controls the electric appliance that has transmitted the start request so that the electric appliance is started based on the start permission command. The start permission command is, for example, a "command to start the electric appliance immediately" or a "command to start the electric appliance after a predetermined time (several seconds to several tens of seconds) has elapsed after receiving the start permission command", and is a start permission command that shifts the start times (start timing) of the electric appliances so that the electric appliances do not start simultaneously. Note that the start permission command may be a command to specify the start times of the electric appliances, so that the start times of the electric appliances are shifted so that the electric appliances do not start simultaneously.

[0046] If only one start request signal is received in S10, a negative determination is made in S11 and the process proceeds to S15. In S15, it is determined whether the start time of the electric device whose start time was delayed when arbitration of start times was performed in S14 in the previous routine (start time based on the start permission command) is synchronized with the start time of the electric device based on the start request signal received in S10 this time. When the server 200 transmits a start permission command of "a command to immediately start the electric device" in response to the start request signal received in S10 this time, if the start time of the electric device overlaps with the start time of the electric device whose start time was delayed when arbitration of start times was performed in S14 in the previous routine (start time based on the start permission command) (if they start simultaneously), an affirmative determination is made in S15 and the process proceeds to S12.

[0047] If startup timing arbitration was not performed in S14 in the previous routine, a negative determination is made in S15 and the process proceeds to S16. Even if startup timing arbitration was performed in S14 in the previous routine, if a startup permission command of "a command to immediately start an electric device" is sent in response to the startup request received in S10 this time, and the startup timing of the electric device does not overlap with the startup timing of the electric device whose startup timing was delayed when startup timing arbitration was performed in S14 in the previous routine (the startup timing based on the startup permission command), a negative determination is made in S15 and the process proceeds to S16.

[0048] In S12 following S15, the total power fluctuation ΣΔkW is calculated by adding the power fluctuation ΔkW caused by the inrush current in the electric device that has transmitted the current start-up request signal received in S10 (hereinafter also referred to as the current electric device) and the power fluctuation ΔkW caused by the inrush current in the electric device whose start-up time overlaps with the current electric device due to the start-up time arbitration in S14 in the previous routine, and the process proceeds to S13. The process of S13 is as described above.

[0049] In S16, in response to the start request signal (HEMS controller 30) received in S10, a start permission command "a command to immediately start up the electric device" is transmitted, and the current routine is ended.

[0050] In this embodiment, each electric appliance (electric load) installed in the house 10 transmits a start request to the HEMS controller 30, which requests start accompanied by an inrush current or starting current of a predetermined value or more. Then, when each electric appliance installed in the house 10 receives a start permission command in response to the start request from the HEMS controller 30, it starts based on the start permission command. Then, when the server 200 simultaneously receives start request signals from a plurality of HEMS controllers 30 in the power distribution block DB, if the total power fluctuation amount ΣΔkW obtained by adding up the power fluctuation amount ΔkW due to the inrush current of each electric appliance is equal to or greater than the allowable value α, it arbitrates the start time (start timing) of each electric appliance and transmits a start permission command to each HEMS controller 30 so that the start times of each electric appliance do not overlap (so that each electric appliance does not start at the same time). Therefore, in the power distribution block DB, it is possible to suppress the simultaneous occurrence of inrush currents in the electric appliances installed in each house 10, suppress the occurrence of a large voltage drop, and reduce the impact on the power grid 1. In addition, a large current can be prevented from flowing through the distribution transformer 5 and the distribution line 6 shared by each of the houses 10.

[0051] In the above embodiment, the amount of power fluctuation ΔkW caused by the inrush current is used to determine whether the magnitude of the voltage drop exceeds the allowable level (S12, S13). Alternatively, the amount of frequency fluctuation (ΔHz) caused by the voltage drop may be used to determine whether the magnitude of the voltage drop caused by the inrush current exceeds the allowable level. Also, the magnitude of the voltage drop may be used to determine whether the magnitude of the voltage drop caused by the inrush current exceeds the allowable level.

[0052] In the above embodiment, each electrical appliance in the house 10 arbitrates the start-up timing by transmitting a start-up request to the server 200 and receiving a start-up permission command via the HEMS controller 30. However, the start-up timing of each electrical appliance may be arbitrated by communicating between each electrical appliance in the house 10 and the server 200 without going through the HEMS controller 30.

[0053] In the above embodiment, the server 200 calculates the power fluctuation ΔkW caused by the inrush current in each electrical appliance from the "information (type, rated power consumption, etc.) of the electrical appliance that transmitted the activation request" and the "identification code (ID) of the HEMS controller 30" contained in the activation request signal. However, information on the "power fluctuation ΔkW" of each electrical appliance may be included in the activation request signal transmitted from the HEMS controller 30 to the server 200, and the server 200 may calculate the total power fluctuation ΣΔkW by adding up the received "power fluctuation ΔkW" of each electrical appliance.

[0054] (Modification) When an electrical appliance in a house 10 stops operating, the power consumption of the appliance becomes zero, and power consumption drops sharply. In the power distribution block DB, when electrical appliances in each house 10 stop operating at the same time, the amount of drop in power consumption increases. When power consumption drops sharply, a momentary voltage rise occurs in the distribution transformer 5 and the distribution line 6. The impact of this momentary voltage rise on the distribution transformer 5 and the power grid 1 may not be negligible. In the modified example, in addition to arbitrating the start-up times of electrical appliances, arbitrating the stop times of electrical appliances is also performed to suppress momentary voltage rises in the distribution block DB.

[0055] In a modified example, when each electric appliance installed in the house 10 stops its own operation, it transmits a stop request (OFF request) to the HEMS controller 30 to request that the appliance be stopped. Also, when stopping an electric appliance that is in operation and consumes a large amount of power, the electric appliance transmits a stop request (OFF request) to the HEMS controller 30. For example, when the refrigerator 15 or the air conditioner 16 is in operation and the electric compressor (electric motor) is to be stopped, the refrigerator 15 or the air conditioner 16 transmits a stop request to the HEMS controller 30.

[0056] When the HEMS controller 30 receives a stop request, it transmits "information (type, rated power consumption, etc.) of the electrical device that transmitted the stop request" and "identification code (ID) of the HEMS controller 30" as a stop request signal to the server 200. When the server 200 receives stop request signals from multiple HEMS controllers 30 simultaneously in the power distribution block DB, it arbitrates the stop times (stop timing) of each electrical device and transmits a stop permission command to each HEMS controller 30 so that the stop times of each electrical device do not overlap (so that each electrical device does not stop at the same time). When the stop request signal received from the HEMS controller 30 does not overlap with the stop times of other electrical devices (so that each electrical device does not stop at the same time), the server 200 transmits a stop permission command to the HEMS controller 30 (without arbitration). When the HEMS controller 30 receives the stop permission command from the server 200, it controls the electrical device that transmitted the stop request so that the electrical device is stopped based on the stop permission command. In addition, for electrical appliances that consume little power and whose impact on the power grid 1 can be ignored even if they are stopped at the same time, the appliances may be stopped without sending a stop request (OFF request) to the HEMS controller 30.

[0057] Fig. 4 is a flowchart showing an example of a process executed by the server 200 in the modified example. This flowchart is repeatedly processed at predetermined intervals by the server 200. This process is executed by the server 200 for each power distribution block DB in addition to the process according to the flowchart in Fig. 3.

[0058] 4, steps S20 to S26 are substantially the same as steps S10 to S16 in FIG. 3, except that the signal received by the server 200 from the HEMS controller 30 is replaced with a stop request signal (FIG. 4) instead of a start request signal (FIG. 3). In S20, it is determined whether or not a stop request signal has been received from the HEMS controller 30. If a stop request signal has not been received, a negative determination is made and the current routine is terminated.

[0059] If a stop request signal has been received, the process proceeds to S21 in which it is determined whether multiple stop request signals have been received. If stop request signals have been received from multiple HEMS controllers 30, it is determined that multiple stop request signals have been received (positive determination), and the process proceeds to S22.

[0060] In S22, the server 200 calculates the total power fluctuation amount ΣΔkW. The server 200 calculates the power fluctuation amount ΔkW when each electrical appliance is stopped from the "information (type, rated power consumption, etc.) of the electrical appliance that transmitted the stop request" and the "identification code (ID) of the HEMS controller 30" contained in the stop request signal received in S20. For example, the server 200 calculates the power fluctuation amount ΔkW when stopped from the type and rated current consumption of the electrical appliance that transmitted the stop request. The server 200 calculates the power fluctuation amount ΔkW when operation is stopped for each stop request signal received in S20 (for each ID of the HEMS controller 30), and calculates the total power fluctuation amount ΣΔkW by adding up all the calculated power fluctuation amounts ΔkW.

[0061] In the next S23, it is determined whether the magnitude (absolute value) of the total power fluctuation amount ΣΔkW is equal to or greater than a threshold value β. If the magnitude of the total power fluctuation amount ΣΔkW is equal to or greater than the threshold value β (|ΣΔkW|≧β), a positive determination is made and the process proceeds to S24. The threshold value β is set, for example, based on an allowable upper voltage level in the power grid 1. In S23, if the magnitude of the total power fluctuation amount ΣΔkW is smaller than the threshold value β (|ΣΔkW|<β), a negative determination is made and the process proceeds to S26.

[0062] In S24, arbitration of stop times is performed between the stop request signals (between the IDs of the HEMS controllers 30) received in S20. In the present disclosure, arbitration of stop times means transmitting a stop permission command in which the stop times (stop timing) of the electric appliances are shifted so that the electric appliances are not stopped at the same time. For example, a stop permission command is transmitted to the HEMS controller 30 so that the electric appliance with the largest power fluctuation amount ΔkW is immediately stopped. Then, after the electric appliance with the largest power fluctuation amount ΔkW is stopped, a stop permission command is transmitted to the corresponding HEMS controller 30 in order of the magnitude of the power fluctuation amount ΔkW at an interval of several seconds so that the electric appliances are stopped in order. The arbitration method of stop times is arbitrary. For example, a stop permission command may be sent to each HEMS controller 30 starting from the HEMS controller 30 with the lowest ID so that each electrical appliance is stopped with an interval of several seconds between each stop, or a stop permission command may be sent to each HEMS controller 30 using a priority based on the type of electrical appliance so that each electrical appliance is stopped with an interval of several seconds between each stop.

[0063] The HEMS controller 30 that has received the stop permission command controls the electric appliance that has transmitted the stop request so that the electric appliance is stopped based on the stop permission command. The stop permission command is, for example, a "command to immediately stop the electric appliance" or a "command to stop the electric appliance after a predetermined time (several seconds to several tens of seconds) has elapsed after receiving the stop permission command", and is a stop permission command that staggers the stop times of the electric appliances so that the electric appliances do not stop simultaneously. Note that the stop permission command may be a command to specify the stop times of the electric appliances, staggering the stop times of the electric appliances so that the electric appliances do not stop simultaneously.

[0064] If only one stop request signal is received in S20, a negative determination is made in S21 and the process proceeds to S25. In S25, it is determined whether or not the stop time of the electric appliance whose stop time was delayed when arbitration of the stop time was performed in S24 in the previous routine (stop time based on the stop permission command) is synchronized with the stop time of the electric appliance due to the stop request signal received this time in S20. When the server 200 transmits a stop permission command of "a command to immediately stop the electric appliance" in response to the stop request signal received this time in S20, if the stop time of the electric appliance overlaps with the stop time of the electric appliance whose stop time was delayed when arbitration of the stop time was performed in S24 in the previous routine (stop time based on the stop permission command) (if they are stopped simultaneously), an affirmative determination is made in S25 and the process proceeds to S22.

[0065] If stop time arbitration was not performed in S24 in the previous routine, a negative determination is made in S25 and the process proceeds to S26. Even if stop time arbitration was performed in S24 in the previous routine, if a stop permission command of "a command to immediately stop the electric appliance" is sent in response to the stop request received in S20 this time, and the stop time of the electric appliance does not overlap with the stop time of the electric appliance whose stop time was delayed when stop time arbitration was performed in S24 in the previous routine (the stop time based on the stop permission command), a negative determination is made in S25 and the process proceeds to S26.

[0066] In S22 following S25, the total power fluctuation amount ΣΔkW is calculated by adding the power fluctuation amount ΔkW of the electric appliance that has transmitted the stop request signal received in S20 this time (also referred to as the current electric appliance) and the power fluctuation amount ΔkW of the electric appliance whose stop time overlaps with the current electric appliance because the stop time was arbitrated in S24 in the previous routine, and the process proceeds to S23. The process of S23 is as described above.

[0067] In S26, in response to the start request signal (HEMS controller 30) received in S20, a "command to immediately stop the electric device" is transmitted as a stop permission command, and the current routine is ended.

[0068] According to this modified example, in the distribution block DB, it is possible to prevent inrush currents from occurring simultaneously in the electrical equipment installed in each residence 10, thereby preventing a large voltage drop from occurring, and also to prevent the electrical equipment installed in each residence 10 from shutting down simultaneously, causing a momentary voltage rise.

[0069] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0070] 1 Power grid, 2 Transmission line, 3 Distribution substation, 4 Distribution line, 5 Distribution transformer, 6 Distribution line, 7 Inlet line, 8 Domestic power line, 10 House, 11 Distribution board, 12 Power conditioner, 13 Photovoltaic power generation device, 14 Heat pump water heater, 15 Refrigerator, 16 Air conditioner (heating and cooling device), 17 Charging and discharging equipment, 20 Shared battery, 30 HEMS controller, 40 Electric vehicle, 50 Smart meter, 100 Power system, 200 Server, 300 Server, DB Distribution block.

Claims

1. A plurality of homes connected to a distribution transformer that transforms power from a power grid; An electrical load installed in each of the plurality of residences; a server capable of receiving information about the electric load; The electric load is configured to transmit a start request for requesting start accompanied by an inrush current or a starting current of a predetermined value or more, and to perform the start based on a start permission command in response to the start request, the server is configured to, when it receives the start-up requests simultaneously from the electrical loads installed in the plurality of houses, arbitrate the start-up timings of the electrical loads and transmit the start-up permission command when a parameter related to a voltage drop caused by the inrush current or the starting current is equal to or greater than an allowable value.

2. the parameter relating to the voltage drop is a power fluctuation amount due to the inrush current or the starting current, The server, determining the amount of power fluctuation for each of the electrical loads; At the same time, the power fluctuations of the electric loads that have issued the start-up requests are added together to calculate a total power fluctuation. The power system according to claim 1 , configured to arbitrate start-up times of the electric loads and transmit the start-up permission command when the total amount of power fluctuation is equal to or greater than the allowable value.

3. Each of the plurality of residences includes a controller capable of controlling a plurality of the electric loads installed in the residence; The controller is configured to be able to communicate with the server, The power system according to claim 1 or 2, wherein the controller transmits the start-up request to the server and starts up the electric load based on the start-up permission command received from the server.

4. The electrical load is configured to transmit a stop request for requesting a stop of operation, and to perform the stop of operation based on a stop permission command in response to the stop request, 2. The power system according to claim 1, wherein the server is configured to, when the server receives the stop requests simultaneously from the electrical loads installed in the plurality of houses, arbitrate the timing of stopping the electrical loads and transmit the stop permission command when a parameter related to a voltage increase accompanying the operation stop is equal to or greater than a threshold value.

5. the parameter relating to the voltage rise is an amount of power fluctuation due to the stop of operation, The server, determining the amount of power fluctuation for each of the electrical loads; At the same time, the power fluctuation amounts of the electric loads that have issued the stop requests are added together to calculate a total power fluctuation amount; The power system according to claim 4 , configured to arbitrate a stop time of the electric load and transmit the stop permission command when the total amount of power fluctuation is equal to or greater than the threshold value.

6. Each of the plurality of residences includes a controller capable of controlling a plurality of the electric loads installed in the residence; The controller is configured to be able to communicate with the server, The power system according to claim 4 or 5, wherein the controller transmits the stop request to the server and stops the operation of the electric load based on the stop permission command received from the server.

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