Power supply system, control device, control method, and program

Abstract

To provide a power supply system capable of appropriately maintaining the amount of electricity stored in a storage battery even when it is sunny or raining continuously.SOLUTION: A power supply system 1 includes a DC bus 9, at least one subsystem 10A-10X connected to the DC bus, and a control device that controls power supply in the subsystem, and the subsystem includes a photovoltaic device, and a storage battery 110A that stores the power generated by a power generation device or the power supplied from a DC bus. The control device includes a pattern storage unit that stores a control pattern that defines the relationship between the difference value between the reference voltage and the measured value and the charge / discharge power, a pattern selection unit that selects a control pattern to be applied from among the control patterns stored in the pattern storage unit, and a charge / discharge control unit that controls charge / discharge of the storage battery according to the control pattern selected by the pattern selection unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power supply system, a control device, a control method, and a program. [Background technology]

[0002] For example, Non-Patent Document 1 discloses an autonomous decentralized control method for controlling the charging and discharging of a storage battery based only on DC voltage in a small-scale area DC power supply system (DC microgrid) that uses renewable energy such as solar power generation. [Prior art documents] [Patent documents]

[0003] [Non-Patent Document 1] "Community Model Demonstration Experiment of the Best Renewable Energy Mix - Autonomous Distributed Control by DC Microgrid Voltage -", Proceedings of the 2019 IEEJ Electronics, Information and Systems Division Conference, OS6-4, pp746-750, September 4, 2019 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a power supply system that can maintain an appropriate amount of stored electricity in a storage battery even when it is sunny or rainy for a long period of time. [Means for solving the problem]

[0005] The power supply system of the present invention is a power supply system including a DC bus, at least one subsystem connected to the DC bus, and a control device that controls the power supply in the subsystem, wherein the subsystem has a power generation device and a storage battery that stores power generated by the power generation device or power supplied from the DC bus, and the control device has a pattern storage unit that stores a control pattern that defines the relationship between the difference between a reference voltage and an actual measured value and charge / discharge power, a pattern selection unit that selects a control pattern to be applied from the control patterns stored in the pattern storage unit, and a charge / discharge control unit that controls the charging and discharging of the storage battery in accordance with the control pattern selected by the pattern selection unit.

[0006] Preferably, the pattern storage unit stores at least one of a control pattern in which the slope of a graph showing the relationship between the differential value and charge / discharge power is asymmetric between the charge side and the discharge side, a control pattern in which the center point of a graph showing the relationship between the differential value and charge / discharge power is shifted to the positive or negative side of the differential value, or a control pattern that is a combination of these.

[0007] Preferably, the control device further has an evaluation unit that evaluates the validity of the control pattern selected by the pattern selection unit at multiple points in time, and a correction unit that corrects the control pattern selected by the pattern selection unit in accordance with the evaluation results by the evaluation unit, and the charge / discharge control unit controls the charging and discharging of the storage battery in accordance with the control pattern corrected by the correction unit.

[0008] Preferably, the power generation device is a solar power generation device, and the evaluation unit evaluates the validity of the control pattern at the present time and at a future time based on weather information for the area where the solar power generation device is installed.

[0009] Preferably, the power generation device is a solar power generation device, and the control device further has a power consumption prediction unit that predicts power consumption at a future point in time, and a power generation amount prediction unit that predicts the amount of power generated by the solar power generation device at a future point in time based on weather information for the area where the solar power generation device is installed, and the pattern selection unit selects the control pattern based on the power consumption predicted by the power consumption prediction unit and the amount of power generation predicted by the power generation amount prediction unit.

[0010] Furthermore, the power supply system of the present invention is a power supply system including a DC bus, a plurality of subsystems connected to the DC bus, and a control device that controls the power supply to the subsystems, wherein the subsystems have a power generation device and a storage battery that stores the power generated by the power generation device or the power supplied from the DC bus, and the control device has a comparison unit that compares current values ​​measured at a plurality of points on the DC bus, and a cutoff instruction unit that cuts off a portion of the DC bus based on the comparison result by the comparison unit.

[0011] Preferably, the cutoff instruction unit determines the point at which to cut off the current based on the comparison result by the comparison unit and the direction of the current at a plurality of points.

[0012] Preferably, the control device further has a judgment table creation unit that creates a judgment table for determining the point to be cut off based on the current measurement position on the DC bus, and the cut-off instruction unit determines the point to be cut off using the judgment table created by the judgment table creation unit.

[0013] In addition, the control device according to the present invention is a control device that controls the power supply of a subsystem having a power generation device and a storage battery, and includes a pattern storage unit that stores a control pattern that defines the relationship between the difference between a reference voltage and an actual measured value and charge / discharge power, a pattern selection unit that selects a control pattern to be applied from the control patterns stored in the pattern storage unit, and a charge / discharge control unit that controls the charging and discharging of the storage battery in accordance with the control pattern selected by the pattern selection unit.

[0014] In addition, the control device of the present invention is a control device that controls the power supply of a subsystem having a power generation device and a storage battery, and includes a differential value acquisition unit that acquires a differential value between an actual measured value of a DC voltage in the subsystem and a reference voltage, and a charge / discharge control unit that controls the charging and discharging of the storage battery in accordance with the differential value acquired by the differential value acquisition unit, according to a control pattern in which the slope of a graph showing the relationship between the differential value and charge / discharge power is asymmetric between the charge side and the discharge side, or a control pattern in which the center point of the graph showing the relationship between the differential value and charge / discharge power is shifted to the positive or negative side of the differential value.

[0015] Furthermore, a control method according to the present invention is a control method for controlling the power supply of a subsystem having a power generation device and a storage battery, and includes a differential value acquisition step of acquiring a differential value between an actual measured value of a DC voltage in the subsystem and a reference voltage, and a charge / discharge control step of controlling the charging / discharging of the storage battery in accordance with the differential value acquired in the differential value acquisition step, in accordance with a control pattern in which the slope of a graph showing the relationship between the differential value and charge / discharge power is asymmetric between the charge side and the discharge side, or in which the center point of the graph showing the relationship between the differential value and charge / discharge power is shifted to the positive or negative side of the differential value.

[0016] In addition, the program of the present invention is a program for controlling the power supply of a subsystem having a power generation device and a storage battery, and causes a computer to execute a differential value acquisition step of acquiring a differential value between an actual measured value of a DC voltage in the subsystem and a reference voltage, and a charge / discharge control step of controlling the charging / discharging of the storage battery in accordance with the differential value acquired in the differential value acquisition step, according to a control pattern in which the slope of a graph showing the relationship between the differential value and charge / discharge power is asymmetric between the charge side and the discharge side, or a control pattern in which the center point of the graph showing the relationship between the differential value and charge / discharge power is shifted to the positive or negative side of the differential value. [Effects of the Invention]

[0017] According to the present invention, even when the weather is sunny or rainy for a long period of time, the amount of stored electricity in the storage battery can be maintained at an appropriate level. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram illustrating an example of the overall configuration of a power supply system 1. FIG. [Figure 2] 1 is a diagram illustrating a control method by an autonomous distributed control system 20. FIG. [Figure 3] FIG. 2 is a diagram illustrating an example of a hardware configuration of a control device 5. [Figure 4] FIG. 2 is a diagram illustrating an example of the functional configuration of a control device 5. [Figure 5] 10 is a flowchart illustrating a power control process (S10) in the power supply system 1. [Figure 6] FIG. 10 is a diagram illustrating an autonomous distributed control process based on a plurality of control patterns. [Figure 7] FIG. 10 is a diagram illustrating an advanced prediction control process. [Figure 8] FIG. 10 is a diagram illustrating a multi-time cross section optimization process. [Figure 9] FIG. 2 is a diagram illustrating a fault point estimation method using the protection coordination system 40. [Figure 10] 10 is a flowchart illustrating protection coordination processing (S20) by the protection coordination system 40. [Figure 11] FIG. 1 is a diagram illustrating a method for estimating a fault point based on the magnitude and direction of a current. [Figure 12] FIG. 10 is a diagram illustrating a decision table. [Figure 13] 10 is a flowchart illustrating a decision table creation process (S30) performed by the protection coordination system 40. [Figure 14] FIG. 10 is a diagram illustrating a control program 62 in a modified example. [Figure 15] 10 is a flowchart illustrating a power control process (S22) in a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an example of the overall configuration of a power supply system 1. As shown in FIG. As illustrated in Figure 1, the power supply system 1 includes a DC bus 9, multiple subsystems 10 (subsystem 10A, subsystem 10B, ..., subsystem 10X) connected to the DC bus 9, an autonomous distributed control system 20 that controls the power supply of each subsystem 10, a multi-time cross-sectional optimization system 30, and a protection coordination system 40. The DC bus 9 is provided with a plurality of sensors 900 for measuring current at a plurality of points, and a plurality of switches 910 for interrupting the DC bus 9 at a plurality of points. The sensors 900 are, for example, current transformers (CTs).

[0020] The subsystems 10 include, for example, a solar power generation device 100, a storage battery 110, and electrical equipment 120 such as home appliances and electric vehicles. In each subsystem 10, the storage battery 110 stores DC power generated by the solar power generation device 100 or DC power supplied from a DC bus 9, and supplies power to the electrical equipment 120 as needed.

[0021] The autonomous distributed control system 20, the multi-time cross-sectional optimization system 30, and the protection coordination system 40 are realized as functions of the control device 5 described below, but are not limited to this and may be realized, for example, as a distributed system. As will be described later with reference to FIG. 2, the autonomous decentralized control system 20 controls the charging and discharging of the storage battery 110 in an autonomous decentralized manner based on the difference (voltage deviation) between the reference voltage of the DC bus 9 and the actual measured value. As will be described later with reference to FIG. 8, the multi-time cross section optimization system 30 optimizes the control pattern used in the autonomous distributed control system 20 by taking into account losses at multiple points in time. The protection coordination system 40 detects a fault current in the DC bus 9 based on the output of the sensor 900, and opens a switch 910 corresponding to the fault point to interrupt the current.

[0022] In addition, the power supply system 1 further includes a weather forecasting system 32, an actual value database 34, a renewable energy power generation forecasting system 36 (renewable energy power generation forecasting system 36), and a power consumption forecasting system 38, which provide necessary information to the autonomous distributed control system 20 or the multi-time cross-section optimization system 30. The weather prediction system 32 predicts the weather in the area where the solar power generation device 100 is installed. For example, the weather prediction system 32 obtains weather forecast information from the Internet network. The actual value database 34 stores actual power generation values ​​and actual power consumption values ​​in each subsystem 10 . The power consumption prediction system 38 predicts the amount of power consumption at a future time point based on the actual power consumption values ​​stored in the actual value database 34 .

[0023] FIG. 2 is a diagram illustrating a control method by the autonomous distributed control system 20. As shown in FIG. 2, the autonomous distributed control system 20 acquires the difference between the actual measured value of the DC voltage in the subsystem 10 and a reference voltage, and controls the charging and discharging of the storage battery 110 so that a control pattern is achieved in which the slope of a graph showing the relationship between this difference and charge / discharge power is asymmetric between the charging side and the discharging side, or a control pattern in which the center point of the graph showing the relationship between this difference and charge / discharge power is shifted to the positive or negative side of this difference. In other words, by allowing an asymmetric slope, a shift of the center point to the left or right, or a combination of these, as shown in FIG. 2, with respect to the relationship between the difference (voltage deviation ΔV) and charge / discharge power ΔP (kW), the storage battery 110 can be operated appropriately even when photovoltaic power generation is continuous (when it is continuously sunny) or when power generation is continuously stopped (when it is continuously raining), etc. For example, if the weather continues to be sunny, there is a high possibility that the storage battery 110 will be fully charged and the output of the solar power generation device 100 will be suppressed, so the autonomous distributed control system 20 controls the charging and discharging of the storage battery 110 using a control pattern that discharges the storage battery 110 in advance to keep the charge amount low and also suppresses the charge amount.If it continues to rain, the opposite is true.

[0024] FIG. 3 is a diagram illustrating an example of the hardware configuration of the control device 5. As shown in FIG. As illustrated in FIG. 3, the control device 5 includes a CPU 500, a memory 502, an HDD 504, a network interface 506 (network IF 506), a display device 508, and an input device 510, and these components are connected to each other via a bus 512. The CPU 500 is, for example, a central processing unit. The memory 502 is, for example, a volatile memory, and functions as a main storage device. The HDD 504 is, for example, a hard disk drive device, and serves as a non-volatile storage device for storing computer programs (for example, the control program 6 in FIG. 4) and other data files. The network IF 506 is an interface for wired or wireless communication, and realizes communication with the sensor 900, the switch 910, and the subsystem 10, for example. The display device 508 is, for example, a liquid crystal display (LCD panel). The input device 510 is, for example, a touch panel.

[0025] FIG. 4 is a diagram illustrating an example of the functional configuration of the control device 5. 4, a control program 6 is installed and operates in the control device 5 of this example. The control program 6 is stored in a recording medium such as a CD-ROM, and is installed in the control device 5 via this recording medium. The control program 6 has a control pattern storage unit 600, a pattern selection unit 605, a difference value acquisition unit 610, a charge / discharge control unit 615, a power generation prediction unit 620, a power consumption prediction unit 625, an evaluation unit 630, a correction unit 635, a judgment table creation unit 640, a judgment table storage unit 645, a comparison unit 650, and a shutdown instruction unit 655. Note that the control program 6 may be partly or entirely implemented by hardware such as an ASIC, or may be implemented by partially borrowing the functions of an OS (Operating System).

[0026] In the control program 6, the control pattern storage unit 600 stores a plurality of control patterns that define the relationship between the difference value between a reference voltage and an actual measurement value and the charge / discharge power. More specifically, the control pattern storage unit 600 stores a control pattern in which the slope of a graph showing the relationship between the difference value (voltage deviation) and the charge / discharge power is asymmetric between the charge side and the discharge side, a control pattern in which the center point of the graph showing the relationship between the difference value (voltage deviation) and the charge / discharge power is shifted to the positive or negative side of the difference value (voltage deviation), and a control pattern that combines these. As illustrated in FIG. 6, the control pattern storage unit 600 of this example stores a normal pattern in which the slope of the graph is symmetric and the center point of the graph is at the origin O, a weak discharge pattern, a strong discharge pattern, a weak charge pattern, and a strong charge pattern.

[0027] The pattern selection unit 605 selects a control pattern to be applied from among the control patterns stored in the control pattern storage unit 600. For example, the pattern selection unit 605 selects a control pattern based on the power consumption predicted by the power consumption prediction unit 625 and the power generation amount predicted by the power generation amount prediction unit 620. The pattern selection unit 605 in this example functions as the multi-time cross-section optimization system 30, and selects an optimal control pattern from among the multiple control patterns stored in the control pattern storage unit 600, taking into account the output control loss at multiple points in time, the transmission loss of the DC bus 9, and the DDC conversion loss (conversion loss of the DC / DC converter) using the objective function of Fig. 8.

[0028] The difference value acquisition unit 610 acquires the difference value (voltage deviation) between the actual measured value of the DC voltage in each subsystem and the reference voltage. The charge / discharge control unit 615 controls the charging / discharging of the storage battery 110 in accordance with the differential value acquired by the differential value acquisition unit 610, in accordance with a control pattern in which the slope of a graph showing the relationship between the differential value (voltage deviation) and the charge / discharge power is asymmetric between the charging side and the discharging side, or a control pattern in which the center point of the graph showing the relationship between the differential value (voltage deviation) and the charge / discharge power is shifted to the positive side or the negative side of the differential value (voltage deviation). The charge / discharge control unit 615 of this example functions as the autonomous distributed control system 20, and controls the charging / discharging of the storage battery 110 in an autonomous distributed manner in accordance with the differential value acquired by the differential value acquisition unit 610, in accordance with the control pattern selected by the pattern selection unit 605.

[0029] The power generation amount prediction unit 620 predicts the amount of power generated by the photovoltaic power generation device 100 at a future time point based on weather information for the area where the photovoltaic power generation device 100 is installed. The power generation amount prediction unit 620 in this example functions as the renewable energy power generation amount prediction system 36, and predicts the amount of power generation at a future time point based on weather information provided by the weather prediction system 32 and the power generation record stored in the record value database 34. The power consumption prediction unit 625 predicts the future power consumption in the subsystem 10. In this example, the power consumption prediction unit 625 functions as the power consumption prediction system 38, and predicts the future power consumption of the subsystem 10 based on the actual power consumption values ​​stored in the actual value database 34.

[0030] The evaluation unit 630 evaluates the appropriateness of the control pattern at multiple points in time for the control pattern selected by the pattern selection unit 605. The evaluation unit 630 in this example functions as the autonomous distributed control system 20 in Fig. 7 and determines whether the control pattern is appropriate by confirming that the occurrence of output control of photovoltaic power generation will be minimized even in the future through advanced predictive control or that the operation of the storage battery 110 is appropriate.

[0031] The correction unit 635 corrects the control pattern selected by the pattern selection unit 605, depending on the evaluation result by the evaluation unit 630. For example, depending on the evaluation result by the evaluation unit 630, the correction unit 635 may instruct the pattern selection unit 605 to reselect a control pattern, may change the slope of the control pattern selected by the pattern selection unit 605, or may shift the graph of the control pattern selected by the pattern selection unit 605 up, down, left, or right.

[0032] The decision table creating unit 640 creates a decision table for determining the point at which power should be cut off, based on the current measurement position on the DC bus 9. A specific method for creating the decision table will be described later with reference to FIG. The decision table storage unit 645 stores the decision table created by the decision table creation unit 640 . The comparison unit 650 compares the current values ​​measured at a plurality of points on the DC bus 9 based on the output value of the sensor 900 . The tripping instruction unit 655 controls the switch 910 to trip a part of the DC bus 9 based on the comparison result by the comparison unit 650. More specifically, the tripping instruction unit 655 determines a point at which the DC bus 9 is to be tripped based on the comparison result by the comparison unit 650 and the judgment table stored in the judgment table storage unit 645, and opens or closes the switch 910 corresponding to the determined point. The judgment table creation unit 640, the comparison unit 650, and the tripping instruction unit 655 of this example function as a protection coordination system 40, as will be described later with reference to Figs. 9 to 13 .

[0033] FIG. 5 is a flowchart illustrating the power control process (S10) in the power supply system 1. As shown in FIG. 5, in step 100 (S100), the power generation amount prediction unit 620 (FIG. 4) of the control device 5 predicts the future power generation amount by the solar power generation device 100 based on the actual power generation amount value of the solar power generation device 100 stored in the actual value database 34 and the weather information provided by the weather prediction system 32.

[0034] In step 105 (S105), the power consumption prediction unit 625 predicts future power consumption in the subsystem 10 based on the actual power consumption values ​​in the subsystem 10 stored in the actual value database . In step 110 (S110), the difference value acquisition unit 610 predicts the target voltage of the DC bus 9.

[0035] In step 115 (S115), the pattern selection unit 605 selects a control pattern to be applied from among the multiple control patterns stored in the control pattern storage unit 600 based on a multi-time optimization process (described later with reference to FIG. 8). In step 120 (S120), the evaluation unit 630 evaluates the validity of the control pattern selected by the pattern selection unit 605 based on the forward prediction control process (described later with reference to FIG. 7).

[0036] In step 125 (S125), if the evaluation unit 630 determines that the control pattern is appropriate, the control program 6 proceeds to processing of S135, and if the evaluation unit 630 determines that the control pattern is inappropriate, the control program 6 proceeds to processing of S130. In step 130 (S130), the modifying unit 635 modifies the control pattern selected by the pattern selecting unit 605.

[0037] In step 135 (S135), the charge / discharge control unit 615 controls the charge / discharge of the storage battery 110 in accordance with the control pattern selected by the pattern selection unit 605 and in response to the difference value (voltage deviation) acquired by the difference value acquisition unit 610.

[0038] In step 140 (S140), the control program 6 continues charge / discharge control based on the same control pattern for a predetermined time (S140: No), and proceeds to the process of S145 after the predetermined time has elapsed (S140: Yes). In step 145 (S145), the control program 6 proceeds to the control process for the next time. In step 150 (S150), the control program 6 continues processing S100 to S145 until the subsystem 10 to be controlled stops (S150: No), and when the subsystem 10 to be controlled stops, it ends the power control processing (S10) (S150: Yes).

[0039] FIG. 6 is a diagram illustrating an autonomous distributed control process based on a plurality of control patterns. As illustrated in Figure 6, the control pattern storage unit 600 stores multiple control patterns in association with power generation trends and power consumption trends, and the autonomous distributed control system 20 (pattern selection unit 605) selects a control pattern corresponding to the future power generation amount predicted by the renewable energy power generation amount prediction system 36 (power generation amount prediction unit 620) and the future power consumption amount predicted by the power consumption amount prediction system 38 (power consumption prediction unit 625), and the autonomous distributed control system 20 (charge / discharge control unit 615) controls the charging and discharging of the storage battery 110 in accordance with the selected control pattern.

[0040] FIG. 7 is a diagram illustrating the advanced prediction control process. As illustrated in Fig. 7, the autonomous distributed control system 20 (evaluation unit 630) evaluates the validity of the control pattern selected by the pattern selection unit 605 at a future point in time based on the future power generation predicted by the renewable energy power generation prediction system 36 (power generation prediction unit 620) and the future power consumption predicted by the power consumption prediction system 38 (power consumption prediction unit 625). When the selected control pattern is applied, the validity of the control pattern is evaluated higher the less output suppression of the photovoltaic power generation device 10 occurs, and the more appropriately the operation of the storage battery 110 is evaluated higher. If the validity of the control pattern is below a standard, the correction unit 535 corrects the control pattern. In this way, by performing a forward simulation from the present time to a future time, it becomes possible to control the charging and discharging of the storage battery 110 with an appropriate control pattern up to a future time.

[0041] FIG. 8 is a diagram illustrating the multi-time cross section optimization process. As illustrated in FIG. 8, the multi-time-section optimization system 30 calculates, as an objective function (FIG. 8), the sum of the output control loss, the power transmission loss of the DC bus 9, and the DDC conversion loss at multiple time points based on the future power generation amount predicted by the renewable energy power generation amount prediction system 36 (power generation amount prediction unit 620) and the future power consumption amount predicted by the power consumption amount prediction system 38 (power consumption prediction unit 625), and selects a control pattern that minimizes this sum. Thus, by the multi-time-section optimization process, future losses can be taken into account when selecting a control pattern.

[0042] FIG. 9 is a diagram for explaining the accident point estimation method by the protection coordination system 40. As illustrated in FIG. 9, the protection coordination system 40 identifies the magnitude of the current by sensors 900 provided at multiple points on the DC bus 9, compares the magnitudes of the identified currents, estimates the accident point, and opens the switch 910 corresponding to the accident point to cut off the current. For example, in the example of this figure, when CT1 < CT2 < CT3 < CT4, the accident point is estimated to be FT45, and switch SW34 is opened. Similarly, when CT1 > CT2 > CT3 > CT4, the accident point is estimated to be FT01. Also, when CT1 < CT2 and CT3 > CT4, the accident point is estimated to be FT23. Thus, the protection coordination system 40 can estimate the accident point simply by comparing the magnitudes of the currents on the DC bus 9, and can open the switch 910 corresponding to the accident point to cut off the current.

[0043] FIG. 10 is a flowchart for explaining the protection coordination process (S20) by the protection coordination system 40. Note that the protection coordination system 40 is implemented by the determination table creation unit 650, determination table storage unit 645, comparison unit 650, and cutoff instruction unit 655 in FIG. 4. As shown in FIG. 10, in step 200 (S200), the comparison unit 650 compares the current values detected by each of the plurality of sensors 900 with a preset threshold value. In step 205 (S205), if the comparison unit 650 determines that both current values ​​are below the threshold, the protection coordination system 40 terminates the protection coordination processing, and if the comparison unit 650 determines that either current value is greater than the threshold, the protection coordination system 40 proceeds to processing of S210. In step 210 (S210), the comparison unit 650 compares the current values ​​detected by the multiple sensors 900. The interruption instruction unit 655 estimates the fault point based on the determination table of FIG. 12(A) and the comparison result by the comparison unit 650, and opens the corresponding switch 910.

[0044] FIG. 11 is a diagram for explaining a method for estimating a fault point based on the magnitude and direction of a current. As illustrated in Fig. 11, the protection coordination system 40 may identify the magnitude and direction of the current using sensors 900 installed at multiple points on the DC bus 9, and estimate the fault point based on the identified magnitude and direction of the current. In this case, the flowchart in Fig. 10 can be applied as is, except that a determination table illustrated in Fig. 12(B) is applied and the direction of the current is taken into consideration.

[0045] FIG. 13 is a flowchart illustrating the decision table creation process (S30) performed by the protection coordination system 40. As shown in FIG. 13, in step 300 (S300), the decision table creation unit 640 models the DC bus 9 and the subsystem 10 (small-scale area DC power supply system) as an electric circuit. In step 305 (S305), the decision table creation unit 640 sets the installation position of the sensor 900 (CT position) and the assumed fault point in the modeled electric circuit in response to the user's operation. In step 310 (S310), the decision table creation unit 640 simulates the occurrence of an accident using an electric circuit model. In step 315 (S315), the decision table creation unit 640 identifies the magnitude and direction of the fault current at the CT position from the simulation results. In step 320 (S320), the judgment table creation unit 640 determines whether or not a simulation of an accident occurring at all assumed accident points has been performed. If simulations have been performed for all assumed accident points, the process proceeds to S325. If there are any assumed accident points that have not yet been simulated, the process returns to S310 and a simulation is performed for the next assumed accident point. In step 325 (S325), the decision table creating unit 640 creates a decision table based on the magnitude and direction of the identified fault current, and registers the created decision table in the decision table storage unit 645.

[0046] As described above, according to the power supply system 1 of this embodiment, by using various control patterns exemplified in FIG. 6, even when the amount of power generated by solar power generation changes significantly due to continuous sunny or rainy weather, the amount of power stored in the storage battery 110 can be maintained at an appropriate level, and the DC microgrid can be operated stably and appropriately without suppressing the output of the solar power generation device 100. Furthermore, according to the power supply system 1 of this example, even if a short circuit accident, a ground fault accident, or the like occurs, the protection coordination system 40 can partially shut down only the accident location without shutting down the entire system, thereby allowing power generation and storage to continue in healthy locations.

[0047] Although the embodiments of the present invention have been described, the above embodiments are presented as examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The above embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims.

[0048] FIG. 14 illustrates an example of a control program 62 in the modified example, and FIG. 15 is a flowchart illustrating the power control process (S22) in the modified example. In the above embodiment, the control pattern is selected by the pattern selection unit 605. However, in a modified example, the pattern setting unit 660 sets the control pattern according to the tendency of the amount of power generation and the tendency of power consumption (S107). In this way, the control device 5 of the modified example may be configured to set a control pattern each time based on the amount of power generated and consumed in the future, rather than selecting a control pattern. [Explanation of symbols]

[0049] 1. Power supply system 5. Control device 20 Autonomous Distributed Control System 30 Multi-time cross-section optimization system 40 Protection and Coordination System

Claims

1. A power supply system including a DC bus, at least one subsystem connected to the DC bus, and a control device that controls power supply in the subsystem, The subsystem comprises: A power generation device; a storage battery that stores the power generated by the power generation device or the power supplied from the DC bus; and The control device a pattern storage unit that stores a control pattern that defines the relationship between the difference between a reference voltage and an actual measurement value and charge / discharge power; a pattern selection unit that selects a control pattern to be applied from among the control patterns stored in the pattern storage unit; a charge / discharge control unit that controls charging / discharging of the storage battery in accordance with the control pattern selected by the pattern selection unit; and the pattern storage unit stores at least one of a control pattern in which the gradient of a graph showing the relationship between the difference value and charge / discharge power is asymmetric between the charge side and the discharge side, a control pattern in which the center point of the graph showing the relationship between the difference value and charge / discharge power is shifted to the positive side or negative side of the difference value, or a control pattern that is a combination of these; The control device an evaluation unit that evaluates the validity of the control pattern selected by the pattern selection unit at a plurality of time points; a correction unit that corrects the control pattern selected by the pattern selection unit according to the evaluation result by the evaluation unit; and The charge / discharge control unit controls charging / discharging of the storage battery in accordance with the control pattern corrected by the correction unit. Power supply system.

2. the power generation device is a solar power generation device, The evaluation unit evaluates the validity of a control pattern at a current time and a future time based on weather information of an area where the solar power generation device is installed. The power supply system according to claim 1 .

3. A power supply system including a DC bus, at least one subsystem connected to the DC bus, and a control device that controls power supply in the subsystem, The subsystem comprises: A power generation device; a storage battery that stores the power generated by the power generation device or the power supplied from the DC bus; and The control device a pattern storage unit that stores a control pattern that defines the relationship between the difference between a reference voltage and an actual measurement value and charge / discharge power; a pattern selection unit that selects a control pattern to be applied from among the control patterns stored in the pattern storage unit; a charge / discharge control unit that controls charging / discharging of the storage battery in accordance with the control pattern selected by the pattern selection unit; and the power generation device is a solar power generation device, The control device a power consumption prediction unit that predicts power consumption at a future point in time; a power generation amount prediction unit that predicts the amount of power generated by the photovoltaic power generation device at a future time point based on weather information of an area where the photovoltaic power generation device is installed; and The pattern selection unit selects the control pattern based on the amount of power consumption predicted by the power consumption prediction unit and the amount of power generation predicted by the power generation prediction unit. Power supply system.

4. A control device for controlling power supply to a subsystem having a power generation device and a storage battery, a pattern storage unit that stores a control pattern that defines the relationship between the difference between a reference voltage and an actual measurement value and charge / discharge power; a pattern selection unit that selects a control pattern to be applied from among the control patterns stored in the pattern storage unit; a charge / discharge control unit that controls charging / discharging of the storage battery in accordance with the control pattern selected by the pattern selection unit; and the pattern storage unit stores at least one of a control pattern in which the gradient of a graph showing the relationship between the difference value and charge / discharge power is asymmetric between the charge side and the discharge side, a control pattern in which the center point of the graph showing the relationship between the difference value and charge / discharge power is shifted to the positive side or negative side of the difference value, or a control pattern that is a combination of these; an evaluation unit that evaluates the validity of the control pattern selected by the pattern selection unit at a plurality of time points; a correction unit that corrects the control pattern selected by the pattern selection unit according to the evaluation result by the evaluation unit; and The charge / discharge control unit controls charging / discharging of the storage battery in accordance with the control pattern corrected by the correction unit. Control device.

5. A control device for controlling power supply to a subsystem having a power generation device and a storage battery, a pattern storage unit that stores a control pattern that defines the relationship between the difference between a reference voltage and an actual measurement value and charge / discharge power; a pattern selection unit that selects a control pattern to be applied from among the control patterns stored in the pattern storage unit; a charge / discharge control unit that controls charging / discharging of the storage battery in accordance with the control pattern selected by the pattern selection unit; and the power generation device is a solar power generation device, a power consumption prediction unit that predicts power consumption at a future point in time; a power generation amount prediction unit that predicts the amount of power generated by the photovoltaic power generation device at a future time point based on weather information of an area where the photovoltaic power generation device is installed; and The pattern selection unit selects the control pattern based on the amount of power consumption predicted by the power consumption prediction unit and the amount of power generation predicted by the power generation prediction unit. Control device.

6. A control method for controlling power supply to a subsystem having a power generation device and a storage battery, comprising: a difference value acquisition step of acquiring a difference value between an actual measured value of a DC voltage in the subsystem and a reference voltage; a charge / discharge control step of controlling the charge / discharge of the storage battery according to the differential value acquired in the differential value acquisition step, in accordance with a control pattern in which the slope of a graph showing the relationship between the differential value and charge / discharge power is asymmetric between the charge side and the discharge side, or a control pattern in which the center point of the graph showing the relationship between the differential value and charge / discharge power is shifted to the positive side or the negative side of the differential value; an evaluation step of evaluating the validity of the control pattern used in the charge / discharge control step at a plurality of time points; a correction step of correcting a control pattern used in the charge / discharge control step according to the evaluation result in the evaluation step; and The charge / discharge control step controls the charge / discharge of the storage battery according to the control pattern corrected by the correction step. Control method.

7. A control method for controlling power supply to a subsystem having a power generation device and a storage battery, comprising: a difference value acquisition step of acquiring a difference value between an actual measured value of a DC voltage in the subsystem and a reference voltage; a charge / discharge control step of controlling the charge / discharge of the storage battery according to the difference value acquired in the difference value acquisition step, in accordance with a control pattern in which the slope of a graph showing the relationship between the difference value and charge / discharge power is asymmetric between the charge side and the discharge side, or a control pattern in which the center point of the graph showing the relationship between the difference value and charge / discharge power is shifted to the positive side or the negative side of the difference value; and the power generation device is a solar power generation device, a power consumption prediction step of predicting power consumption at a future time; a power generation amount prediction step of predicting a power generation amount by the solar power generation device at a future time point based on weather information of an area where the solar power generation device is installed; and The charge / discharge control step selects the control pattern based on the power consumption predicted in the power consumption prediction step and the power generation amount predicted in the power generation amount prediction step, and performs control in accordance with the selected control pattern. Control method.

8. A program for controlling power supply to a subsystem having a power generation device and a storage battery, a difference value acquisition step of acquiring a difference value between an actual measured value of a DC voltage in the subsystem and a reference voltage; a charge / discharge control step of controlling the charge / discharge of the storage battery according to the differential value acquired in the differential value acquisition step, in accordance with a control pattern in which the slope of a graph showing the relationship between the differential value and charge / discharge power is asymmetric between the charge side and the discharge side, or a control pattern in which the center point of the graph showing the relationship between the differential value and charge / discharge power is shifted to the positive side or the negative side of the differential value; an evaluation step of evaluating the validity of the control pattern used in the charge / discharge control step at a plurality of time points; a correction step of correcting a control pattern used in the charge / discharge control step according to the evaluation result in the evaluation step; on the computer, The charge / discharge control step controls the charge / discharge of the storage battery according to the control pattern corrected by the correction step. program.

9. A program for controlling power supply to a subsystem having a power generation device and a storage battery, a difference value acquisition step of acquiring a difference value between an actual measured value of a DC voltage in the subsystem and a reference voltage; a charge / discharge control step of controlling the charge / discharge of the storage battery according to the difference value acquired in the difference value acquisition step, in accordance with a control pattern in which the slope of a graph showing the relationship between the difference value and charge / discharge power is asymmetric between the charge side and the discharge side, or a control pattern in which the center point of the graph showing the relationship between the difference value and charge / discharge power is shifted to the positive side or the negative side of the difference value; on the computer, the power generation device is a solar power generation device, a power consumption prediction step of predicting power consumption at a future time; a power generation amount prediction step of predicting a power generation amount by the solar power generation device at a future time point based on weather information of an area where the solar power generation device is installed; Then, the computer executes The charge / discharge control step selects the control pattern based on the power consumption predicted in the power consumption prediction step and the power generation amount predicted in the power generation amount prediction step, and performs control in accordance with the selected control pattern. program.

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