Power management system

Abstract

To reduce power costs in a construction site where an electric construction machine operates by planing power reception in consideration of power rates different in time zones.SOLUTION: A power management system, when power rates of a first time zone are lower than power rates of a next second time zone, sets power reception electric power of a construction site in the first time zone, based on total consumed power of management object electric apparatuses, so that a total stored power amount of a management object battery in an ending stage of the first time zone becomes equal to or more than the total stored power amount of the management object battery in a starting stage of the first time zone. The power management system, when the power rates of the first time zone are higher than the power rates of the second time zone, sets the power reception electric power of the construction site in the first time zone, based on the total consumed power of the management object electric apparatuses, so that the total stored power amount of the management object battery in the ending stage of the first time zone becomes equal to or less than the total stored power amount of the management object battery in the starting stage of the first time zone.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electric power management system that manages the cost of electricity at a construction site where electric construction machines are operated. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2009-97270 (Patent Document 1) discloses an example in which an electric construction machine is connected to a large-capacity battery facility connected to a system power supply, and the built-in battery of the electric construction machine is quickly charged with electricity stored in the battery facility. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-97270 Summary of the Invention [Problem to be solved by the invention]

[0004] At construction sites, electric construction machinery may operate while connected to a grid power supply. If the electric construction machinery is equipped with a built-in battery, the built-in battery may be charged by the grid power supply while it is operating. Also, at construction sites where a large-capacity battery system (power bank) is installed, as in Patent Document 1, the battery system charged by the grid power supply may be used as the power source for the electric construction machinery.

[0005] At construction sites, various devices are supplied with power, including electric construction machinery and battery equipment. Regardless of the type of equipment being supplied with power, electricity is received from the grid power supply, which incurs electricity charges. While electricity charges per unit of power (e.g., 1 kWh) can vary depending on the time of day, the technology disclosed in Patent Document 1 keeps the battery equipment connected to the grid power supply and in standby mode in preparation for rapid charging of the built-in battery of the electric construction machinery. In the technology disclosed in Patent Document 1, the battery equipment receives power sequentially from the grid power supply regardless of differences in electricity rates between time periods. Therefore, if the amount of received power increases during times when electricity rates are high, for example, electricity costs at the construction site may become higher than expected.

[0006] An object of the present invention is to provide a power management system that can reduce power costs at construction sites where electric construction machinery is operated by planning power reception taking into account electricity rates that vary depending on the time of day. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a power management system comprising a control device that manages the power of a construction site where at least one managed electrical device including an electric construction machine, at least one managed battery whose stored power is consumed by the managed electrical device, and power receiving equipment that supplies power received from a grid power source to the managed battery, and where the control device manages the power of the construction site where the power rate differs between a first time slot and a second time slot that follows the first time slot, and the control device controls the power of the managed battery at the end of the first time slot when the power rate during the first time slot is lower than the power rate during the second time slot. and when the electricity rate for the first time period is higher than the electricity rate for the second time period, sets the received power of the construction site during the first time period based on the total power consumption of the managed electrical devices so that the total stored power amount of the managed batteries at the end of the first time period is equal to or less than the total stored power amount of the managed batteries at the start of the first time period. [Effects of the Invention]

[0008] According to the present invention, by planning power reception taking into account the different power rates depending on the time of day, it is possible to reduce the power costs at a construction site where electric construction machines are operated. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating an example of a construction site that is a target for managing received power by a power management system of the present invention. [Figure 2] 1 is a block diagram showing the main functions of a control device constituting a power management system according to a first embodiment of the present invention, the functions relating to power management at a construction site. [Figure 3] 5 is a flowchart illustrating an example of a procedure for setting received power at a construction site by a control device that configures the power management system according to the first embodiment of the present invention. [Figure 4] 10 is a flowchart illustrating an example of a procedure for setting received power at a construction site by a control device constituting a power management system according to a second embodiment of the present invention. [Figure 5] 10 is a flowchart illustrating an example of a procedure for setting received power at a construction site by a control device constituting a power management system according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a model diagram showing a comparison between received power set in a power management system according to a second embodiment of the present invention and a conventional example. [Figure 7] FIG. 10 is a model diagram showing a comparison of received power set in a power management system according to a second embodiment of the present invention and power charges in a conventional example. [Figure 8] FIG. 10 is a block diagram showing the main functions relating to power management at a construction site of a control device constituting a power management system according to a third embodiment of the present invention. [Figure 9] 10 is a flowchart illustrating an example of a procedure for correcting received power at a construction site by a control device that configures a power management system according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a model diagram showing a comparison between the received power set in a power management system according to a third embodiment of the present invention and the received power set in the second embodiment. [Figure 11] FIG. 10 is a model diagram showing a comparison of the power rates for received power set in a power management system according to a second embodiment of the present invention and received power set in the second embodiment. [Figure 12] FIG. 11 is a model diagram showing a comparison of the power rates for received power set in a power management system according to a modified example and received power set in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] First Embodiment -Construction site- FIG. 1 is a schematic diagram showing an example of a construction site where received power is managed by a power management system of the present invention.

[0012] The construction site S shown in FIG. 1 is equipped with at least one electrical device to be managed, at least one battery to be managed whose stored power is consumed by the managed electrical device, and power-receiving equipment that supplies power received from a grid power source G to the managed battery. At the construction site S, the electricity rate per unit of power used from the grid power source varies depending on the time of day, and the electricity rate (unit price) per unit of power used (e.g., 1 kWh) differs between a first time period and a second time period that follows the first time period. For example, the electricity rate per unit of power used from 7:00 AM to 1:00 PM and from 4:00 PM to 11:00 PM is the standard rate specified in the rate plan, and the electricity rate from 11:00 PM to 7:00 AM is lower than the standard rate, and the electricity rate from 1:00 PM to 4:00 PM is higher than the basic rate.

[0013] Here, the "electrical equipment to be managed" described in this specification includes electrically driven machinery such as lighting fixtures 151, power tools 152, and electric trucks 153, as well as electrically driven construction machinery using electric motors as prime movers. Electric construction machinery includes, for example, a battery-powered hydraulic excavator 101 equipped with an internal battery 201, and a cable-connected hydraulic excavator 102 that operates while receiving a supply of power from an external power source (a grid power source G or a battery facility 202 described below) connected via a power cable L without a battery. The internal battery 201 is, for example, a 200 kWh lithium-ion battery. If the internal battery 201 can be discharged while charging, the battery-powered hydraulic excavator 101 can also operate while receiving a supply of power from an external power source via the power cable L. As an example, in FIG. 1, of two hydraulic excavators 102, the right hydraulic excavator 102 is equipped with an internal battery 201, and is shown operating on the power stored in the internal battery 201 while receiving power from an external power source via a power cable L to charge the internal battery 201. The hydraulic excavators 101, 102 are also equipped with a controller 110, which is a computer that controls on-board electrical equipment including an electric motor. In the battery-powered hydraulic excavator 101, the controller 110 monitors the remaining charge (SOC) of the internal battery 201. Although a hydraulic excavator has been given as an example of construction machinery, other construction machinery such as a wheel loader or a bulldozer may also be used as electric construction machinery.

[0014] Furthermore, the "battery to be managed" described in this specification includes at least one of the built-in battery 201 of the electric construction machine and a large-capacity battery facility (power bank) 202 deployed at the construction site S as an external power source for the electric construction machine. The battery facility 202 can discharge (while charging) while connected to the grid power supply G. If electrical equipment other than the electric construction machine, such as the lighting fixture 151, power tool 152, or electric truck 153, is equipped with a built-in battery, these built-in batteries may also be included in the "battery to be managed." The battery facility 202 has a large capacity of, for example, 400 kWh and is equipped with a charging / discharging device (not shown). The charging / discharging device can supply a constant AC power of, for example, 20 kW to the electric construction machine or other electric equipment, or can rapidly charge the built-in battery 201 of the electric construction machine at a constant power of, for example, 150 kW. While FIG. 1 illustrates a fixed battery facility 202 installed at the construction site S, depending on its size, the battery facility 202 may be configured to be towable, such as by being mounted on a cart, and moved as needed within the construction site S. Furthermore, it goes without saying that the electricity stored in the battery equipment 202 can be used not only for electric construction machinery but also for electrical equipment such as lighting fixtures 151 and power tools 152, and for charging the built-in battery of the electric truck 153. Furthermore, the battery equipment 202 is equipped with a controller 210, which is a computer that controls charging and discharging by the charging and discharging device, and the remaining charge (SOC) of the battery equipment 210 is monitored by the controller 210.

[0015] Furthermore, the "power receiving equipment" described in this specification refers to equipment that supplies power received from a power grid G ​​to equipment connected via a power cable L, and in this example, a distribution board 301 is used as the power receiving equipment. FIG. 1 illustrates a configuration in which a battery equipment 202 and a cable container (power tap) 251 are connected to the distribution board 301, and power is supplied to the battery equipment 202 and the cable container 251 via the distribution board 301. Although the configuration in which two hydraulic excavators 102 are connected to the cable container 251 via a power cable L is illustrated, there is also a case in which the hydraulic excavators 102 or electrical equipment such as lighting fixtures 151 and power tools 152 are connected to the distribution board 301 without using the cable container 251. The power supply path from the power receiving equipment to the power supply target can be changed as appropriate. Note that a distribution board and a control panel related to the distribution board 301 are not shown in FIG. 1.

[0016] -Power Management System- The power management system of the present invention includes a control device that manages the power of a construction site S. The construction site S where the power is managed by the control device may be one or multiple. The control device is a computer having a storage device and an arithmetic unit, and may be configured, for example, as a single computer 401, or may be configured so that functions are shared among multiple computers 401, 402 connected via a network NW such as the Internet. When the control device is configured with multiple computers 401, 402, these multiple computers 401, 402 can be installed in separate facilities away from each other. It is also possible to configure part or all of the control device using the controllers 110 of the hydraulic excavators 101, 102.

[0017] As an example, in this embodiment, the control device is configured with a single computer 401, and hydraulic excavators 101, 102 are operating as electric construction machines at the construction site S. The computer 401 is, for example, a server installed in a management center M that manages the construction site S. The computer 401 and the controllers 110, 210 of the hydraulic excavators 101, 102 and the battery equipment 202 are each connected to (or equipped with) a communication device (not shown) in the local network of the construction site S, and the computer 401 and the controllers 110, 210 can communicate bidirectionally via the local network of the construction site S. When the management center M is located away from the construction site S, for example, as shown in FIG. 1 , the controllers 110, 210 of the hydraulic excavators 101, 102 and the battery equipment 202 can be connected to a wireless base station X via a mobile phone communication network, and the controllers 110, 210 can be connected to the computer 401 via the wireless base station X and the network NW.

[0018] -Control device- The computer 401 has a function to set the received power [kW] of the construction site S during the first time period based on the total power consumption [kW], which is the total value of the power consumption per unit time of the managed electrical equipment, so that when the electricity rate during the first time period is lower than the electricity rate during the second time period, such as during the time periods AB and BC shown in Figure 6, the total stored power (total remaining stored power) [kWh] of the managed batteries at the end of the first time period (time B) is greater than or equal to the total stored power [kWh] of the managed batteries at the start of the first time period (time A). In addition, when the electricity rate for the first time period is higher than the electricity rate for the second time period, such as in the time periods BC and CD shown in Figure 6, the computer 401 has a function to set the received power [kW] of the construction site S during the first time period based on the total power consumption [kW] of the managed electrical equipment so that the total stored power [kWh] of the managed batteries at the end of the first time period (time C) is less than or equal to the total stored power [kWh] of the managed batteries at the start of the first time period (time B).

[0019] The computer 401 also has a function of outputting the set received power as a power receiving plan to the monitor 55 (FIG. 1), notifying the manager of the construction site S, and prompting the manager to adjust the received power [kW] of the construction site S. The received power of the construction site S can be adjusted by adjusting the received power of the power receiving equipment (distribution board 301) or the managed batteries (battery equipment 202 and built-in battery 201). The received power by the distribution board 301 can be adjusted by directly operating the distribution board 301, but it is also possible to configure the adjustment by operating the computer 401 to send a control signal to the control board of the distribution board 301, for example. Furthermore, the received power of the built-in batteries 201 and battery equipment 202 of the hydraulic excavators 101, 102 can be adjusted by operating the computer 401 to send a control signal to the controllers 110, 210, for example. When there is an intermediate management device (computer) that manages at least one part of the electric construction machines, the transmission of control signals to the electric construction machines is performed via the intermediate management device.

[0020] In addition, the computer 401 may be configured to control the distribution board 301 or the managed battery by sending a command signal to the control panel of the distribution board 301 or the controllers 110, 210 of the hydraulic excavators 101, 102 or the battery equipment 202 according to the set received power, thereby adjusting the received power at the construction site S.

[0021] 2 is a block diagram showing the main functions of the control device (computer 401) related to power management of the construction site S. The computer 401 includes a power fee management unit 411, a total stored power amount calculation unit 412, a total power consumption calculation unit 413, a total stored power amount planning unit 414, and a received power planning unit 415. These are functions of the control device, and may be realized by hardware such as an integrated circuit, or by software.

[0022] The power rate management unit 411 outputs power rate information related to the construction site S. The power rate information is the rate per unit of power used for each time period, such as 30 yen / kWh for the time period from 11:00 PM to 7:00 AM (for example, time period DA in FIG. 6) and 45 yen / kWh for the time period from 1:00 PM to 4:00 PM (for example, time period BD in FIG. 6). This power rate information can be input into the power rate management unit 411 by sequentially downloading the power rate plan of the power company with which the construction site S has a contract via the network NW, by reading data pre-stored in the storage device 54 (FIG. 1) of the computer 401, by reading data pre-stored in the storage device 59 (FIG. 1) of the computer 402 connected via the network NW, or by the administrator inputting the information via the input device 56 (FIG. 1).

[0023] The total stored power calculation unit 412 calculates the total stored power [kWh] of the construction site S. The total stored power of the construction site S is the sum of the remaining stored power of the managed batteries deployed at the construction site S. Specifically, the computer 401 receives the remaining stored power (SOC) of the built-in batteries 201 and the battery equipment 202 transmitted from the controllers 110 of the hydraulic excavators 101, 102 and the controller 210 of the battery equipment 202, and adds these up to calculate the total stored power at each point in time of the construction site S. The total stored power of the construction site S is calculated sequentially and stored in a storage device such as the storage device 54.

[0024] The total power consumption calculation unit 413 calculates the total power consumption [kW] of each managed electrical device at the construction site S per unit time, and the total power consumption (kWh) of the construction site S during a predetermined period based on the total power consumption. The total power consumption [kW] of the construction site S is a calculated or measured value based on the power consumption of managed electrical devices operating at the construction site S, such as the hydraulic excavators 101 and 102, the lighting fixtures 151, and the power tools 152, for example, the rated output of the managed electrical devices. The power consumption [kW] of each managed electrical device can be the rated output of each managed electrical device listed in a catalog or the like (e.g., 40 kW for the hydraulic excavator 101, 3 kW for the lighting fixture 151, etc.), and the total power consumption per unit time can be calculated by adding up these values. The power consumption of each managed electrical device during operation can also be a value measured in advance and stored in the storage device 54, or an actual value measured for a certain period (e.g., approximately 30 minutes) during operation at the construction site S, i.e., an actual value based on the operation history, etc. It is more preferable that the actual value is based on a relatively recent operation history, for example, a value from one day ago or an operation history for a certain period up to the present. When calculating the total power consumption [kW] for a specified period, for example, the operation time of each managed electrical device may be estimated based on the daily work plan for the construction site S input by the administrator (for example, earth loading work from 8:00 AM to 12:00 PM, breaks from 12:00 PM to 1:00 PM, etc.), and the total power consumption may be calculated from the estimated operation time and power consumption of each managed electrical device.

[0025] The total energy storage amount planning unit 414 calculates a target value for the total energy storage amount based on the electricity rate for each time period input from the electricity rate management unit 411, the total energy storage amount input from the total energy storage amount calculation unit 412, and the total power consumption input from the total power consumption calculation unit 413. As described above, the total energy storage amount is determined by comparing the electricity rates for two consecutive time periods (time periods with different electricity rates), and planning a target total energy storage amount for each time period so that if the electricity rate for the first time period is lower than that for the second time period, the total energy storage amount increases (does not decrease) at the end of the first time period compared to the beginning, and if the electricity rate for the first time period is higher than that for the second time period, the total energy storage amount decreases (does not increase) at the end of the first time period compared to the beginning,

[0026] The received power planning unit 415 calculates the received power for each time slot of the construction site S based on the target value of the total stored power calculated by the total stored power planning unit 414 and the total power consumption calculated by the total power consumption calculation unit 413. For example, the received power for the first time slot is set by taking the difference [kWh] between the target value of the total stored power at the end of the first time slot and the total stored power at the start of the first time slot and the total power consumption [kWh] during the first time slot. The method for calculating the received power is not limited, but essentially, if the power rate for the first time slot is cheaper than that for the second time slot, the amount of inexpensive power received during the first time slot is increased, and if the power rate for the first time slot is higher than that for the second time slot, the amount of expensive power received during the first time slot is reduced. The received power set by the received power planning unit 415 is output to the monitor 55 as a notification to the administrator, as described above, or converted into a control signal for the received power and transmitted to the distribution board 301 (or the hydraulic excavators 101, 102 or the battery equipment 202).

[0027] -Setting / controlling receiving power- Fig. 3 is a flowchart showing an example of a procedure for setting the receiving power of the construction site S by the control device (computer 401). The computer 401 executes the process of Fig. 3 at a predetermined timing, for example, at regular time intervals (every 30 minutes, every hour, etc.). For example, if the current time belongs to time interval AB in the example of Fig. 6, time interval AB is the first time slot, time interval BC is the second time slot, time A is the start of the first time slot, time B is the end of the first time slot (the start of the second time slot), and time C is the end of the second time slot.

[0028] When the computer 401 starts the processing of Figure 3, it first reads the electricity rate for the construction site S (step S301) and calculates the total power consumption [kW] of the construction site S per unit time (step S302). The electricity rate data is stored in advance in, for example, the storage device 54 by the electricity rate management unit 411, and is read from the storage device 54. However, the method for reading the electricity rate is not limited, and for example, as described above, the electricity rate plan may be downloaded and read via the network NW. The total power consumption is calculated by the total power consumption calculation unit 413, as described above. Thereafter, the computer 401 compares the electricity rates for the first time slot and the second time slot, and determines whether the electricity rate for the first time slot is lower than the electricity rate for the second time slot (step S303).

[0029] If the electricity rate is lower in the first time slot than in the second time slot (Yes), the computer 401 sets the target value [kWh] of the total amount of stored energy at the end of the first time slot to be greater than the total amount of stored energy [kWh] at the beginning of the first time slot (step S304). In this procedure, the total amount of stored energy at the beginning of the first time slot is calculated by the total amount of stored energy calculation unit 412 as described above. The target value of the total amount of stored energy at the end of the first time slot is calculated, for example, by multiplying the total amount of stored energy at the beginning of the first time slot by a predetermined coefficient greater than 1 (e.g., 1.1) or by adding a predetermined value (>0). However, this target value is limited to be equal to or less than an upper limit value set based on the sum of the maximum amount of stored energy according to the specifications of each of the managed batteries.

[0030] If the electricity rate for the first time slot is higher than that for the second time slot (No), the computer 401 sets the target value [kWh] of the total amount of stored power at the end of the first time slot to be smaller than the total amount of stored power [kWh] at the start of the first time slot (step S305). In this procedure, the target value of the total amount of stored power at the end of the first time slot is calculated, for example, by multiplying the total amount of stored power at the start of the first time slot by a predetermined coefficient (e.g., 0.9) that is greater than 0 and less than 1, or by subtracting a predetermined value (>0). However, this target value is limited to a lower limit set based on the sum of the minimum amount of stored power (the minimum amount required for the driven electrical equipment to operate) of each of the managed batteries.

[0031] After setting the target value of the total amount of stored power for the end of the first time slot, computer 401 sets the received power [kW] based on the target value [kWh] of the total amount of stored power for the end of the first time slot and the total amount of power consumed [kWh] from the current time to the end of the first time slot, and outputs the result to monitor 55 and controls power reception (step S306). The total amount of power consumed [kWh] can be calculated by multiplying the total power consumed [kW] calculated in step S302 by the time [h] until the end of the first time slot. The received power [kW] is calculated, for example, as follows, assuming that it is constant from the current time to the end of the first time slot.

[0032] Received power [kW] = (change in total stored power [kWh] + total power consumption [kWh]) / time [h] However, the received power [kW], the change in total stored energy [kWh], the total power consumption [kWh], and the time [h] are all values ​​from the current time to the end of the first time slot. The change in total stored energy [kWh] is the difference between the target value of the total stored energy at the end of the first time slot determined in step S304 and the total stored energy at the current time. The total power consumption [kWh] is the product of the total power consumption [kW] calculated in step S302 and the remaining time [h] from the current time to the end of the first time slot.

[0033] After step S306 is executed, the computer 401 temporarily ends the processing of FIG. 3, and then repeatedly executes the processing of FIG. 3 at regular time intervals.

[0034] 3 described above, for example, at the start of a first time slot, computer 401 predicts the total power consumption [kWh] for the first time slot, and if the electricity rate for the first time slot is lower than the electricity rate for the second time slot, sets the target value [kWh] for the total storage amount of the managed batteries at the end of the first time slot to be larger than the total storage amount [kWh] of the managed batteries at the start of the first time slot. Conversely, for example, at the start of a first time slot, if the electricity rate for the first time slot is higher than the electricity rate for the second time slot, computer 401 sets the target value [kWh] for the total storage amount of the managed batteries at the end of the first time slot to be smaller than the total storage amount [kWh] of the managed batteries at the start of the first time slot. The computer 401 then sets the received power of the construction site S in the first time slot based on the target value [kWh] of the total stored power amount at the end of the first time slot, which is set in accordance with the magnitude relationship between the electricity rates in the first time slot and the second time slot, and the predicted total power consumption [kWh], and outputs the set received power as a planned value to the monitor 55, for example. Also, the control device 401 may transmit a received power control signal to the distribution board 301 or the hydraulic excavators 101, 102 and the battery equipment 202, and control the received power of the construction site S by controlling the distribution board 301 or the managed batteries (the built-in battery 201 and the battery equipment 202).

[0035] That is, computer 401 determines whether the electricity rate will increase or decrease in the next second time slot, and if the electricity rate will increase in the second time slot, it receives more electricity than consumed during the current first time slot to store the electricity and sets the received power for the first time slot to prepare for saving electricity in the second time slot when the rate will increase. Conversely, if the electricity rate will decrease in the next second time slot, computer 401 sets the received power to be moderate in the current first time slot, on the assumption that it will wait until the second time slot when the rate will decrease and receive more electricity.

[0036] -effect- (1) As described above, in this embodiment, a surplus is secured in the total amount of stored electricity at the construction site S during times when electricity rates are relatively low, and the surplus is used during times when electricity rates are relatively high, thereby reducing power reception. This makes it possible to increase the proportion of electricity received during times when electricity rates are low in the total amount of electricity received at the construction site S in one day. In this way, according to this embodiment, by planning power reception taking into account electricity rates that vary by time period, it is possible to reduce the electricity costs at the construction site S where electric construction machinery is operated.

[0037] Furthermore, this embodiment is expected to have a CO2 reduction effect. When a power generation facility that runs on fossil fuels and a power generation facility that runs on renewable energy are connected to a grid power source G, electricity is generally transmitted from the various power generation facilities to the grid power source G during times when electricity demand is high and electricity rates are high. In other words, during times when electricity rates are high, the amount of electricity transmitted to the grid power source G from power generation facilities that run on fossil fuels or power generation facilities with low power generation efficiency tends to increase, and during times when electricity demand and electricity rates are low, the amount of electricity transmitted tends to decrease. In this embodiment, electricity rates are low and the proportion of electricity received from relatively clean energy increases, which can also contribute to CO2 reduction.

[0038] At a construction site S that uses a grid power supply G, it is possible to reduce electricity charges while securing the necessary power by setting a contract power. However, unlike fixed facilities such as factories that are expected to operate stably over the long term, the power demand at a construction site S involving temporary construction work fluctuates depending on the progress of the work, making it difficult to flexibly respond to the site's power demand and reduce costs simply by setting a contract power. In contrast, in this embodiment, instead of simply receiving power according to power consumption, the power rate for each time period is calculated, and the received power is increased or decreased relative to the power consumption according to the power rate, thereby enabling a flexible response to fluctuations in power demand and changing construction periods and rationally reducing power costs.

[0039] Furthermore, the power monitoring system of the present invention differs in nature from power supply facilities for electric vehicles. In the case of electric vehicles, for example, even if one vehicle is charged at a certain power supply facility, it is not known where the vehicle, which is a means of transportation, will be charged next. In contrast, at a construction site S where electric construction machinery is operated, the power supply targets are mainly electric construction machinery, tools, lighting, and other equipment, which remain and operate at the construction site S. Because the power supply targets do not leave the construction site S, it is easy to grasp the total amount of stored power and total amount of power consumed at the construction site S. In this embodiment, by planning power reception by taking advantage of the characteristics of the operation site of this electric construction machinery, power costs can be rationally reduced.

[0040] Second Embodiment A power management system according to a second embodiment of the present invention will be described. The second embodiment is a variation of the processing content of a control device (e.g., a computer 401). In this embodiment, the control device sets a limit value for the total amount of stored power [kWh] at the construction site S, refrains from receiving power as much as possible during a first time slot in which the electricity rate is higher than during a second time slot, and sets the received power to 0 when possible. The control device also sets an upper limit target value and a lower limit target value that limit the total amount of stored power within a predetermined range. As a preferred example, the upper limit target value is set as the target value for the total amount of stored power at the start of the time slot in which the electricity rate is highest, and the lower limit target value is set as the target value for the total amount of stored power at the start of the time slot in which the electricity rate is lowest. A specific example will be described using the flowcharts of FIGS. 4 and 5. In this specific example, the computer 401 executes the processing as the control device.

[0041] -Setting / controlling receiving power- 4 and 5 are flowcharts showing an example of the procedure for setting the receiving power of the construction site S by the control device (computer 401). FIG. 5 shows a specific example of the procedure of step S405 in FIG. 4. In the process shown in the flowchart in FIG. 4 (including FIG. 5), the receiving power for each time period of a day is set once. This process is executed at a predetermined timing. The predetermined timing is, for example, every fixed period such as every day or every week, when the work plan for the construction site S is input or updated, when instructed by an administrator, etc.

[0042] 4 starts, the computer 401 first reads the data on the electricity rate (step S401). The process of step S401 is the same as the process of step S301 in FIG.

[0043] The computer 401 also calculates the expected transition of the total power consumption [kw] of the construction site S based on the work plan for the construction site S (step S402). The work plan is, for example, read from data created by a manager or the like and stored in the storage device 54 or the like. Alternatively, the manager or the like can input new data. The work plan specifies the types and numbers of managed electric devices operating at the construction site S, and also specifies the type of work (such as gravel loading) for which each managed electric device will be used, as well as the time and duration of the work.

[0044] The computer 401 also reads the upper limit target value [kWh] and the lower limit target value [kWh] of the total amount of stored power at each point in time for the construction site S (step S403). The upper limit target value and the lower limit target value are set values ​​that can be arbitrarily set, and for example, data set by an administrator or the like and stored in the storage device 54 or the like is read. The upper limit target value may be set to a maximum value, for example, the total amount of stored power (maximum amount of stored power according to specifications) of all managed batteries deployed at the construction site S when fully charged, or a value lower than the maximum value by a predetermined margin. The lower limit target value may be set to a minimum value, for example, the total amount of minimum amount of stored power required for the managed electrical equipment, particularly the electric construction machines (hydraulic excavators 101, 102) and the battery equipment 202, that is the minimum amount, or a value higher than the minimum value by a predetermined margin. In some cases, the computer 401 may automatically set the upper limit target value and the lower limit target value based on catalog values ​​for each managed electrical equipment.

[0045] Furthermore, the computer 401 sets the target value of the total energy storage amount at the start of the time period in a day when the electricity rate at the construction site S is the highest (for example, time B in the example of FIG. 6) to an upper limit target value, and sets the target value of the total energy storage amount at the start of the time period in a day when the electricity rate at the construction site S is the lowest (for example, time D in the example of FIG. 6) to a lower limit target value (step S404). In this process, it is also possible to set the target value of the total energy storage amount at the start of the time period in which the electricity rate is the highest to the upper limit target value, or to simply set the target value of the total energy storage amount at the start of the time period in which the electricity rate is the lowest to the lower limit target value. In this example, the target value of the total energy storage amount at least at the start of the time period in which the electricity rate is the highest is set to the upper limit target value.

[0046] Thereafter, the computer 401 sets a target value for the total amount of stored power at the end of each time period of the day (step S405). The processing of step S405 will be described later with reference to FIG.

[0047] Then, the computer 401 sets the received power [kW] for each time period (from start to end) based on the target value of the total stored amount of power at the end of each time period and the total power consumption [kWh] for each time period, outputs this to the monitor 55, and starts power reception control of the received power at the construction site S in accordance with the set received power for each time period (step S406). The received power is a value of 0 or more. The received power in step S406 can be calculated in the same way as the processing in step S306, based on the transition of the total power consumption calculated in step S402. The processing related to setting the received power ends after the procedure in step S406.

[0048] Next, a specific example of the processing in step S405 will be described with reference to Fig. 5. In the processing in step S405, the computer 401 creates a daily power receiving plan by setting the power to be received for each time period of the day (time periods with different power rates) at the construction site S, for example, in order from the time period with the highest power rate.

[0049] When the processing of step S405 starts, the computer 401 first determines the time period with the highest electricity rate (time period BC in the example of FIG. 6) as the first time period, compares the electricity rate of the first time period with that of the next second time period, and determines whether the electricity rate of the first time period is higher than that of the second time period (step S405a). In the first round of processing, the electricity rate of the first time period is the highest in the day, so the determination of step S405a is automatically satisfied. Also, in the first round of processing, because the electricity rate of the first time period is the time period with the highest electricity rate, the upper limit target value has already been set for the total amount of stored energy at the start, as described above. If the electricity rate of the first time period is higher than that of the second time period (Yes), the computer 401 proceeds from step S405a to step S405b. If the electricity rate of the first time period is lower than that of the second time period (No), the computer 401 proceeds from step S405a to step S405e.

[0050] If the electricity rate for the first time slot is higher than that for the second time slot, the computer 401 determines whether the predicted total amount of stored energy at the end of the first time slot will fall below the lower limit target value even if no power is received during the first time slot (step S405b). The predicted total amount of stored energy at the end of the first time slot when no power is received is calculated by subtracting the total amount of power consumed during the first time slot from the total amount of stored energy at the beginning of the first time slot. The total amount of power consumed during the first time slot is calculated as the integral of the first time slot based on the transition of the total power consumption calculated in step S402.

[0051] If it is determined that the total amount of stored power at the end of the first time slot will not fall below the lower limit target value even if no power is received during the first time slot (Yes), the computer 401 sets the target value for the total amount of stored power at the end of the first time slot to the predicted value calculated in step S405b (=total amount of stored power at the start of the first time slot - total power consumption during the first time slot) (step S405c), and proceeds to step S405h. In this case, the received power during the first time slot is set to 0 in the processing of step 406.

[0052] If it is determined that the total amount of stored power at the end of the first time slot falls below the lower limit target value when the received power for the first time slot is 0 (No), the computer 401 sets the target value for the total amount of stored power at the end of the first time slot to the lower limit target value (step S405d) and proceeds to step S405h. In this case, the received power for the first time slot is set so that the total amount of stored power at the end of the first time slot is equal to the lower limit target value in the subsequent processing of step 406.

[0053] If the electricity rate for the first time slot is lower than that for the second time slot, the computer 401 determines whether the predicted total amount of stored power at the end of the first time slot will exceed the upper limit target value if the maximum amount of power is received within the contracted power of the construction site S during the first time slot (step S405e). The predicted total amount of stored power at the end of the first time slot if the maximum amount of power is received is calculated by adding the maximum received power during the first time slot to the total amount of stored power at the start of the first time slot. The maximum received power for the first time slot is calculated based on the contracted power of the construction site S, the individual specifications of the managed electrical equipment and managed batteries, and the time of the first time slot.

[0054] If it is determined that the total amount of stored power at the end of the first time slot exceeds the upper limit target value if the maximum amount of power is received during the first time slot (Yes), the computer 401 sets the target value for the total amount of stored power at the end of the first time slot to the upper limit target value (step S405f) and proceeds to step S405h. In this case, the received power during the first time slot is set so that the total amount of stored power at the end of the first time slot coincides with the upper limit target value in the processing of later step 406.

[0055] If it is determined that the total amount of stored power at the end of the first time slot will not exceed the upper limit target value even if the maximum amount of power is received during the first time slot (No), the computer 401 sets the target value of the total amount of stored power at the end of the first time slot to the predicted value calculated in step S405e (= total amount of stored power at the start of the first time slot + maximum received power during the first time slot) (step S405g), and proceeds to step S405h. In this case, the received power during the first time slot is set to the maximum value in the subsequent processing of step 406.

[0056] After setting the received power for the first time slot in step S405c, S405d, S405f, or S405g, the computer 401 determines whether setting the received power for all time slots of the day is complete (step S405h). If not completed (No), the computer 401 sets the next time slot to the first time slot (step S405i) and returns to step S405a to set the received power for the next time slot. For example, in the example of FIG. 6, if setting the received power for time segment BC is completed, the computer 401 sets the next time segment CD to the first time slot and proceeds to setting the received power for time segment CD. In this way, the computer 401 executes the setting process for the received power for each time slot in order, and when setting the received power for all time slots of the day is completed (Yes), the computer 401 completes the procedure of step S405 in FIG. 5 and proceeds to step S406 (FIG. 4).

[0057] The received power can be set to a constant value for each time period, but since fluctuations in power consumption at the construction site can be estimated from the work plan, the same time period during which the power rate does not change (for example, time period BC in Figure 6) can be divided into multiple sections according to the trend in total power consumption, and a target value for the total stored power amount and received power can be set for each of these sections.

[0058] 3 described above, if the electricity rate for the first time slot is lower than the electricity rate for the second time slot and the predicted value of the total amount of stored energy at the end of the first time slot when the maximum amount of power is received until the end of the first time slot is greater than the upper limit target value, the computer 401 sets the target value of the total amount of stored energy at the end of the first time slot to the upper limit target value.If the electricity rate for the first time slot is lower than the electricity rate for the second time slot and the predicted value of the total amount of stored energy at the end of the first time slot when the maximum amount of power is received until the end of the first time slot is equal to or less than the upper limit target value, the computer 401 sets the target value of the total amount of stored energy at the end of the first time slot to the predicted value.

[0059] Furthermore, if the electricity rate for the first time slot is higher than the electricity rate for the second time slot and the predicted value of the total amount of stored energy at the end of the first time slot when energy is not stored until the end of the first time slot is equal to or greater than the lower limit target value, the computer 401 sets the target value of the total amount of stored energy at the end of the first time slot to that predicted value.If the electricity rate for the first time slot is higher than the electricity rate for the second time slot and the predicted value of the total amount of stored energy at the end of the first time slot when energy is not stored until the end of the first time slot is less than the lower limit target value, the computer 401 sets the target value of the total amount of stored energy at the end of the first time slot to the lower limit target value.

[0060] Then, the computer 401 sets the received power of the construction site S in the first time slot based on the predicted total power consumption amount and the target value of the total power storage amount.

[0061] Except for the points described above, this embodiment is similar to the first embodiment.

[0062] -effect- As described above, according to this embodiment, upper and lower target values ​​are set for the total amount of stored electricity at the construction site S, and the maximum amount of electricity is received within the range in which the expected total amount of stored electricity does not exceed the upper target value during times when electricity rates are relatively low, while electricity is received as little as possible during times when electricity rates are relatively high, unless the expected total amount of stored electricity falls below the lower target value, thereby further enhancing the effect of reducing electricity costs at the construction site S.

[0063] Figure 6 is a model diagram comparing the received power set in this embodiment with a conventional example. At a typical construction site, as shown in the conventional example (dotted line) in Figure 6, regardless of the power rate for each time period, for example, power is not received during work, and the total stored power that decreases during work is received in bulk during non-work times (break times or outside of regular working hours). In contrast, in this embodiment, power is received during time periods when the power rate is relatively low in accordance with the trend in the total power consumption of the construction site S, increasing the total stored power, and power reception is minimized during time periods when the power rate is high (for example, time segment BC).

[0064] When comparing the electricity rates for the example in Fig. 6, as shown in Fig. 7, the electricity rate according to this embodiment increases compared to the conventional example during time segment DA when the electricity rate is relatively low, but the electricity rate according to this embodiment decreases significantly compared to the conventional example during time segment AD when the electricity rate is relatively high, resulting in a significant reduction in the daily electricity rate. In a trial calculation of a model case, there were cases where the daily electricity rate was reduced by about 40%.

[0065] Third Embodiment A power management system according to a third embodiment of the present invention will be described. The third embodiment is a variation of the processing content of a control device (for example, computer 401). In this embodiment, the control device corrects the received power in accordance with the current power rate when the current trend of the total amount of stored power deviates from the preset setting. A specific example will be described using Figs. 8 and 9. In this specific example, the computer 401 executes the processing as the control device.

[0066] -Control device- FIG. 8 is a block diagram showing the main functions of the control device (computer 401) related to power management for the construction site S. The computer 401 of this embodiment further includes an operation data management unit 416 and a correction unit 417. That is, the computer 401 includes a power charge management unit 411, a total stored power amount calculation unit 412, a total power consumption calculation unit 413, a total stored power amount planning unit 414, a received power planning unit 415, an operation data management unit 416, and a correction unit 417. As in the first embodiment, these are functions of the control device, and may be realized by hardware such as an integrated circuit or by software. The functions of the power charge management unit 411, the total stored power amount calculation unit 412, the total stored power amount calculation unit 412, the total power consumption calculation unit 413, the total stored power amount planning unit 414, and the received power planning unit 415 are the same as in the first embodiment.

[0067] The operation data management unit 416 acquires and manages operation data of the managed electrical equipment and managed batteries at the construction site S in real time via wireless communication or the like. The operation data managed by the operation data management unit 416 includes, for example, the power consumption of electrically powered equipment such as the hydraulic excavators 101, 102, the amount of electricity stored in each built-in battery 201 (remaining amount of electricity), the amount of electricity stored in the battery equipment 202 (remaining amount of electricity stored) and charging / discharging current, and the power received by the distribution board 301.

[0068] If there is an error between the current total amount of stored power and a preset value, the correction unit 417 corrects the setting of the received power based on the operation data acquired successively while taking into consideration the current electricity price. An example of the correction method will be described with reference to FIG. 9.

[0069] -Setting / controlling receiving power- Fig. 9 is a flowchart showing an example of a procedure for setting the receiving power of the construction site S by the control device (computer 401). The flowchart in Fig. 9 is repeatedly executed during the construction period of the construction site S, and corrects the receiving power controlled under the plan set in the second embodiment, for example.

[0070] 9 starts, the computer 401 acquires operation data including the current amount of stored power (remaining amount of stored power) of each managed battery and the current power consumption of each electrically powered device via, for example, wireless communication (step S901), and calculates the current total amount of stored power at the construction site S (step S902). The current total amount of stored power is the sum of the amounts of stored power (remaining amount of stored power) of each managed battery at the construction site S.

[0071] The computer 401 also calculates the current total power consumption of the construction site S (step S903). For example, the computer 401 calculates the moving average value of the total power consumption (the total value of the current power consumption of each electrically powered device) acquired in real time as the current total power consumption. The moving average value is, for example, the average value for a set time (e.g., 30 minutes) up to the current time. If the set time is too long, the error with the current power consumption will be large, and if it is too short, the calculation result will fluctuate greatly, resulting in overly sensitive correction of the received power.

[0072] Next, the computer 401 compares the electricity rate for the current first time slot with the electricity rate for the next second time slot, and determines whether the electricity rate for the first time slot is higher than that for the second time slot (step S904). If the electricity rate for the first time slot is higher than that for the second time slot (Yes), the computer 401 proceeds from step S904 to step S905, and if the electricity rate for the first time slot is lower than that for the second time slot (No), the computer 401 proceeds from step S904 to step S910.

[0073] If the electricity rate for the first time slot is higher than that for the second time slot, the computer 401 determines whether the current total amount of stored power is less than a set value (step S905). For example, in the second embodiment, a target value for the total amount of stored power at the end of each time slot is set (steps S405c, S405d, S405f, and S405g). At the same time, a target value is set according to the time remaining until the end of each time slot so that the total amount of stored power moves toward the target value at the end of the time slot. In step S905, the target value (set value) for the current time is compared with the actual value calculated in step S902. If the current total amount of stored power is less than the set value (Yes), the computer 401 proceeds from step S905 to step S906. If the current total amount of stored power is equal to or greater than the set value (No), the computer 401 proceeds from step S905 to step S910.

[0074] If the current total amount of stored power is less than the set value, the computer 401 calculates an estimated value of the total amount of stored power at the end of the first time slot (step S906). Here, the estimated value of the total amount of stored power at the end of the first time slot is calculated again by multiplying the moving average value of the total power consumption calculated in step S903 by the remaining time of the first time slot.

[0075] After calculating the predicted value of the total amount of stored power at the end of the first time slot, the computer 401 determines whether the calculated predicted value is below the lower limit target value (step S907). If the predicted value is below the lower limit target value (Yes), the computer 401 proceeds from step S907 to step S908, and if the predicted value is not below the lower limit target value (No), the computer 401 proceeds from step S907 to step S909.

[0076] Then, computer 401 corrects the received power by correction unit 417 so that the total amount of stored power matches the lower limit target value at the end of the first time slot if the predicted value is below the lower limit target value (step S908), and does not correct the received power if the predicted value is not below the lower limit target value (step S909), and ends the processing in Fig. 9. The correction value calculated in step S908 is found by dividing the difference between the lower limit target value and the predicted value calculated in step S906 by the remaining time of the first time slot, and the corrected received power is found by adding the correction value to a preset current received power.

[0077] Furthermore, if the electricity rate in the first time slot is lower than that in the second time slot, or if the electricity rate in the first time slot is higher than that in the second time slot but the current total amount of stored power is equal to or greater than the set value, computer 401 causes correction unit 417 to correct the received power so that the total amount of stored power matches the set value at the end of the first time slot (step S910), and ends the processing in Fig. 9. The correction value calculated in step S910 is found by dividing the difference between the set value and the actual value of the total amount of stored power at the current time by the remaining time of the first time slot, and the corrected received power is found by adding the correction value to the preset current received power.

[0078] To summarize the process of Figure 9 described above, the computer 401 receives the remaining stored power and power consumption transmitted from the managed electrical devices and the managed batteries. During a first time slot, if the electricity rate for the first time slot is lower than the electricity rate for the second time slot, or if the electricity rate for the first time slot is higher than the electricity rate for the second time slot and the current total stored power exceeds the planned value based on the set received power, the computer 401 calculates the difference between the current total stored power and the planned value based on the set received power, and corrects the setting of the received power so that the total stored power at the end of the first time slot matches the planned value. In other words, if the electricity rate for the current time slot is lower than the next time slot, the correction process is performed regardless of the magnitude relationship between the set value and the actual value of the total stored power. An upward correction of the received power is preferable from the perspective of increasing the amount of inexpensive electricity received, and a downward correction is preferable from the perspective of reducing the amount of electricity received that is greater than necessary. In addition, if the electricity rate for the current time period is higher than that for the next time period, but the total amount of stored electricity is currently less than the set amount, the received power is corrected to make up for the shortfall in order to avoid a power shortage at the construction site S.

[0079] Furthermore, during a first time slot, if the electricity rate for the first time slot is higher than the electricity rate for the second time slot and the current total amount of stored energy is lower than the planned value, the computer 401 recalculates a predicted value of the total amount of stored energy at the end of the first time slot from the received power consumption history. If the recalculated predicted value is equal to or greater than the lower limit target value, the computer 401 maintains the setting of the received power, and if the recalculated predicted value is less than the lower limit target value, corrects the setting of the received power so that the total amount of stored energy does not fall below the lower limit target value. In other words, if the electricity rate for the current time slot is higher than that for the next time slot, and if the total amount of stored energy will not fall below the lower limit target value by the next time slot, excessive corrections are avoided to suppress fluctuations in the received power. If there is a risk that the total amount of stored energy will fall below the lower limit target value, the received power is corrected as necessary so that the total amount of stored energy does not fall below the lower limit target value, thereby avoiding shutdown of the managed electrical devices.

[0080] -effect- As described above, according to this embodiment, when the actual value of the total amount of stored power at the construction site S deviates from the set value, the received power is corrected depending on the situation.

[0081] FIG. 10 is a model diagram showing a comparison between the received power set in this embodiment and the received power set in the second embodiment. In the model case in this figure, the actual value of the total power consumption is partially lower than the set value (planned value) in time segment BC. In this case, if the received power is not corrected, the total stored power at time D will be higher than the set value (planned value) due to the decrease in power consumption in time segment BC (dashed line). Ideally, time D is the start of the period when the electricity rate is lowest, so it is desirable for the total stored power to be reduced to the lower limit target amount. In contrast, in this embodiment, the received power is corrected, and the total stored power has been reduced to the set value (planned value) by time D (dashed line).

[0082] When comparing the electricity rates for the example in Fig. 10, as shown in Fig. 11, the electricity rate according to this embodiment increases compared to the second embodiment during time segment DA when the electricity rate is relatively low, but decreases compared to the second embodiment during time segment AD when the electricity rate is relatively high, resulting in a further decrease in the daily electricity rate compared to the second embodiment. In a trial calculation of a model case, there were cases where the daily electricity rate decreased by nearly 10%.

[0083] <Additional remarks> The present invention is not limited to the above-described embodiments and may include various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. It is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0084] For example, the correction of received power in the third embodiment has been described as a case in which the received power set in the second embodiment is corrected so that the total stored power amount becomes the upper or lower target value at a predetermined timing, but the correction of received power in the third embodiment can be applied to any plan in which the total stored power amount is set in advance. For example, it is also possible to create a daily plan for the total stored power amount and received power as a result of simply comparing the electricity rates for two consecutive time periods as in the first embodiment and increasing or decreasing the setting of received power, and the correction in the third embodiment can also be applied to this. The third embodiment is not limited to the second embodiment and can be applied to the first embodiment as well.

[0085] In the third embodiment, the correction method was described as an example in which the correction content was varied by dividing the situation into detailed cases based on a comparison between the current electricity rate and the electricity rate for the next time period. However, the correction process of the control device may be, for example, to correct the setting of the received power so as to reduce the difference between the current total stored energy amount and the planned value based on the set received energy amount. For example, as shown in FIG. 12, a possible correction method is to determine whether the difference between the current total stored energy amount and the set value is within a predetermined tolerance (step S1204), and if it is within the tolerance, no correction is made (step S1205). If it is outside the tolerance, the received energy is increased if the current total stored energy amount is less than expected (steps S1206 and S1207), or decreased if it is more than expected (steps S1206 and S1208). Steps S1201-S1203 are the same as steps S901-S903. Feedback control can be applied to correct the received power, and when increasing the received power, for example, the set value of the received power may be multiplied by a constant coefficient greater than 1 (e.g., 1.1) or a constant value may be added. Conversely, when decreasing the received power, the set value of the received power may be multiplied by a constant coefficient greater than 0 and less than 1 (e.g., 0.9) or a constant value may be subtracted. However, the received power is limited by the minimum and maximum values ​​of the total stored power. [Explanation of symbols]

[0086] 101, 102... Hydraulic excavator (electric construction machine, managed electrical equipment), 110... Controller (control device), 151... Lighting fixture (managed electrical equipment), 152... Power tool (managed electrical equipment), 153... Electric truck (managed electrical equipment), 201... Built-in battery (managed battery), 202... Battery equipment (managed battery, managed electrical equipment), 210... Controller (control device), 301... Distribution board (power receiving equipment), 401, 402... Computer (control device), G... System power supply, S... Construction site

Claims

1. A power management system is provided at a construction site where at least one managed electrical device including an electric construction machine, at least one managed battery whose stored power is consumed by the managed electrical device, and power receiving equipment that supplies power received from a grid power supply to the managed battery, the power management system including a control device that manages the power of the construction site where power rates differ between a first time period and a second time period that follows the first time period, The control device If the electricity rate for the first time period is lower than the electricity rate for the second time period, set the received power of the construction site for the first time period based on the total power consumption of the managed electrical devices so that the total amount of stored power in the managed battery at the end of the first time period is equal to or greater than the total amount of stored power in the managed battery at the start of the first time period; If the electricity rate for the first time period is higher than the electricity rate for the second time period, the received power of the construction site for the first time period is set based on the total power consumption of the managed electrical devices so that the total amount of stored power in the managed battery at the end of the first time period is equal to or less than the total amount of stored power in the managed battery at the start of the first time period. A power management system characterized by:

2. 2. The power management system according to claim 1, The power management system is characterized in that the managed batteries include at least one of a battery facility installed at the construction site and an internal battery of the electric construction machine.

3. 2. The power management system according to claim 1, The power management system is characterized in that the total power consumption is a calculated value or a measured value based on the rated output of the managed electrical devices, or an actual value based on an operation history.

4. 2. The power management system according to claim 1, The control device calculates, as the total amount of stored power, a sum of the remaining amounts of stored power transmitted from the at least one electrical device to be managed.

5. 2. The power management system according to claim 1, The control device controls the power receiving equipment or the managed battery, and adjusts the power received at the construction site.

6. 2. The power management system according to claim 1, The power management system is characterized in that the battery under management can be discharged while being charged.

7. 2. The power management system according to claim 1, The control device predicting a total amount of power consumption during the first time period; When the electricity rate for the first time slot is lower than the electricity rate for the second time slot, a target value of the total amount of stored electricity at the end of the first time slot is set to be larger than the total amount of stored electricity at the start of the first time slot; When the electricity rate for the first time slot is higher than the electricity rate for the second time slot, a target value of the total amount of stored electricity at the end of the first time slot is set to be smaller than the total amount of stored electricity at the start of the first time slot; setting a receiving power of the construction site for the first time period based on the predicted total power consumption amount and a target value of the total power storage amount; A power management system characterized by:

8. 2. The power management system according to claim 1, The control device receiving power consumption and remaining battery charge transmitted from the electrical device to be managed and the battery to be managed; The receiving power setting is corrected to reduce the difference between the current total amount of stored power and the planned value based on the set receiving power. A power management system characterized by:

9. 2. The power management system according to claim 1, The control device a predetermined upper limit target value and a predetermined lower limit target value related to the total amount of stored power of the managed batteries; When the electricity price for the first time slot is lower than the electricity price for the second time slot and the predicted value of the total amount of stored electricity at the end of the first time slot when the maximum amount of electricity is received until the end of the first time slot is greater than the upper limit target value, the target value of the total amount of stored electricity at the end of the first time slot is set to the upper limit target value; when the electricity price for the first time slot is lower than the electricity price for the second time slot and the predicted value of the total amount of stored electricity at the end of the first time slot when the maximum amount of electricity is received until the end of the first time slot is equal to or less than the upper limit target value, setting the target value of the total amount of stored electricity at the end of the first time slot to the predicted value; when the electricity price for the first time slot is higher than the electricity price for the second time slot and the predicted value of the total amount of stored electricity at the end of the first time slot when no electricity is stored until the end of the first time slot is equal to or greater than the lower limit target value, setting the target value of the total amount of stored electricity at the end of the first time slot to the predicted value; when the electricity price for the first time slot is higher than the electricity price for the second time slot and the predicted total amount of stored electricity at the end of the first time slot when no electricity is stored until the end of the first time slot is less than the lower limit target value, setting the target value of the total amount of stored electricity at the end of the first time slot to the lower limit target value; The power received by the construction site during the first time period is set based on the predicted total power consumption amount and the target value of the total power storage amount. A power management system characterized by:

10. 10. The power management system according to claim 9, The control device is characterized in that it sets the target value of the total storage amount at the beginning of the time period when electricity rates are highest to the upper limit target value, or sets the target value of the total storage amount at the beginning of the time period when electricity rates are lowest to the lower limit target value.

11. 10. The power management system according to claim 9, The control device receiving power consumption and remaining battery charge transmitted from the electrical device to be managed and the battery to be managed; In the first time slot, if the electricity price for the first time slot is lower than the electricity price for the second time slot, or if the electricity price for the first time slot is higher than the electricity price for the second time slot and the current total amount of stored electricity exceeds a planned value based on the set received power, A difference between the current total amount of stored power and a planned value based on the set received power is calculated, and the setting of the received power is corrected so that the total amount of stored power at the end of the first time period matches the planned value. A power management system characterized by:

12. The power management system according to claim 11, The control device In the first time slot, if the electricity rate for the first time slot is higher than the electricity rate for the second time slot and the current total amount of stored electricity is lower than the planned value, recalculating an expected value of the total amount of stored electricity at the end of the first time slot from the received power consumption history, If the recalculated predicted value is equal to or greater than the lower limit target value, the setting of the received power is maintained; If the recalculated predicted value is less than the lower limit target value, the setting of the received power is corrected so that the total amount of stored power does not fall below the lower limit target value. A power management system characterized by:

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