Power demand and supply adjustment system and power demand and supply adjustment method

Abstract

To provide a power demand and supply adjustment system that performs accurate power supply and demand adjustment.SOLUTION: A power supply and demand adjustment system according to an embodiment is a system that adjusts the amount of power received from a substation that supplies, to a feeding circuit, DC power obtained by rectifying AC power supplied from an AC power supply, and comprises: a supply and demand adjustment device that acquires a supply and demand adjustment command including adjustment power and a reference value in a supply and demand adjustment execution time zone, and a predicted value of load power of the substation, calculates a charge-discharge power value that is the difference between the predicted value of load power of the substation and target received power based on the adjustment power and the reference value, and generates an adjustment amount for adjusting the load on the AC power supply by using a target power amount based on the charge-discharge power value; and a power storage device that includes a power storage medium, charges the power storage medium with regenerative electric power from the feeding circuit on the basis of the voltage of the feeding circuit and the state of charge of the power storage medium in the supply and demand adjustment execution time zone, and supplies the electric power discharged from the power storage medium to the feeding circuit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] An embodiment of the present invention relates to an electric power supply and demand adjustment system and an electric power supply and demand adjustment method. [Background technology]

[0002] In order to provide a stable supply of electricity, it is essential to secure the supply and demand adjustment capacity to control frequency and adjust the supply and demand balance in the electricity supply area. Supply and demand adjustment capacity is the power supply capacity to match supply (generation) with the ever-changing electricity demand (consumption). In recent years, a supply and demand adjustment market has been established that allows trading of supply and demand adjustment capacity. Various methods have been proposed to provide supply and demand adjustment capacity in accordance with the electricity supply and demand plan required in the supply and demand adjustment market.

[0003] One method for supplying electricity to railway cars (so-called electric trains) on electric railways is, for example, the DC power feed system. In railways that use this DC power feed system, in order to deal with regeneration failure and overhead line voltage drops, the DC power feed system is connected to electric railway substation equipment, which includes storage batteries (hereafter referred to as "storage elements"), power converters, and control devices, and the storage elements are charged and discharged to improve the regeneration rate from the overhead lines and stabilize the overhead line voltage.

[0004] On the other hand, with the recent spread of distributed power sources such as solar and wind power generation, there have been many cases where adjustment capacity is required to control frequency and adjust the supply and demand balance in power supply areas in AC power transmission and distribution systems.

[0005] Conventionally, it has been described that a power storage device having a power storage element and a power converter that charges and discharges the power storage element is connected to a power feed system, and the power storage device is charged and discharged according to commands from a higher-level control device that oversees the power storage device, thereby providing supply and demand adjustment capability. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2023-023565

Summary of the Invention

Problems to be Solved by the Invention

[0007] On the other hand, commands for charge-discharge control of the power storage device from a higher-level control device that oversees the battery may be given in terms of the charge-discharge power value of the battery. At this time, the charge and discharge of the power storage device are performed based on the given charge-discharge power value. However, whether or not power corresponding to the command value can be charged and discharged into the DC power supply system depends on the presence or absence and magnitude of the train load. In some cases, it is impossible to output the command value from the higher-level control device, and the charge-discharge power amount of the power storage device per unit time deviates from the target value, making it difficult to provide an accurate supply-demand adjustment ability.

[0008] Embodiments of the present invention have been made in view of the above circumstances, and an object thereof is to provide a power supply-demand adjustment system that performs accurate power supply-demand adjustment.

Means for Solving the Problems

[0009] The power supply-demand adjustment system according to the embodiment is a system that adjusts the received power amount of a substation that supplies DC power obtained by rectifying AC power supplied from an AC power source to a power supply circuit. The system acquires a supply-demand adjustment command including adjustment power and a reference value in a supply-demand adjustment execution time period and a predicted load power value of the substation, calculates a charge-discharge power value that is the difference between the predicted load power value of the substation and a target received power based on the adjustment power and the reference value, and generates an adjustment amount for adjusting the received power amount from the AC power source using a target power amount based on the charge-discharge power value. The system further includes a power storage device including a power storage medium that charges the power storage medium with regenerative power from the power supply circuit and supplies discharge power of the power storage medium to the power supply wire based on the voltage of the power supply circuit, the adjustment amount, and the charge state of the power storage medium in the supply-demand adjustment execution time period.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the power supply and demand adjustment system and the power supply and demand adjustment method according to the embodiment will be described with reference to the drawings.

[0012] FIG. 1 is a diagram schematically showing a configuration example of the power supply and demand adjustment system according to the present embodiment. In the present embodiment, as an example, a power supply and demand adjustment system applied to a DC power supply system 100 that supplies power to a vehicle (hereinafter referred to as an "electric vehicle") 3 such as an electric railway or a monorail will be described. The DC power supply system 100 supplies DC power to the electric vehicle 3 via a DC power supply line 1 and a return line 2. The return line 2 is, for example, a rail on which the electric vehicle 3 runs. The DC power supply system 100 is grounded by the return line 2.

[0013] The power supply and demand adjustment system according to the present embodiment includes a higher - level control device 8, a supply and demand adjustment device 20, a substation 10, and a power storage device 4. The substation 10 is electrically connected between an AC power supply system (not shown) and a DC circuit (including the DC power supply line 1 and the return line 2). The substation 10 includes a power meter 9, a first transformer 11, a second transformer 13, and a rectifier 12.

[0014] The power meter 9 measures the received power value of the substation 10 receiving power from an AC power system (not shown). The measured value of the power meter 9 is supplied to the upper control device 8 described later.

[0015] The first transformer 11 converts and outputs the voltage of the AC power received from the AC power system. The rectifier 12 outputs the DC power obtained by rectifying the AC power output from the first transformer 11 to the power supply circuit. The second transformer 13 converts the voltage of the AC power received from the AC power system and outputs the AC power that serves as the power supply for the AC loads within the substation, signal facilities, facilities such as stations, etc.

[0016] The upper control device 8 acquires the available adjustment amounts (the amount by which the customer-side load can be reduced (downward DR amount), the amount by which the customer-side load can be increased (upward DR amount)) for the future (e.g., tomorrow) from the supply-demand adjustment device 20 described later and bids in the supply-demand adjustment market. The available adjustment amount may include information on the amount of energy (load) available for supply-demand adjustment and the time. When supply-demand adjustment is activated, the upper control device 8 receives an upper supply-demand adjustment command from the power distribution company on the day of supply-demand adjustment. The upper supply-demand adjustment command from the power distribution company is notified to the upper control device 8 prior to the implementation time of the supply-demand adjustment. The upper supply-demand adjustment command may include information on the time requiring the implementation of the supply-demand adjustment and the adjustment amount of the supply-demand energy. The upper control device 8 creates a supply-demand adjustment command according to the upper supply-demand adjustment command. The supply-demand adjustment command may include the adjusted power value along the upper supply-demand adjustment command, a baseline serving as a reference value (the value of the received power of the substation 10 assumed in the case where there is no supply-demand adjustment command), and the supply-demand adjustment implementation time zone. The upper control device 8 supplies the generated supply-demand adjustment command to the supply-demand adjustment device 20.

[0017] The upper control device 8 acquires and stores the measured value of the received power of the substation 10 from the watt-hour meter 9. Based on the stored measured value of the received power, the upper control device 8 generates a predicted load power value, which is a predicted value of the load power of the substation. For example, the predicted load power value is the average value of the measured values of the received power in a past predetermined period. For example, the predicted load power value on weekdays may be calculated by taking the average value of multiple measured values at the same time (or in the same time zone) in the measured values of the received power on weekdays in a past predetermined period in a time series, or may be calculated by taking the average value of multiple measured values at the same time (or in the same time zone) for each day of the week or each date in a time series. The upper control device 8 supplies the generated predicted load power value to the supply-demand adjustment device 20 together with a supply-demand adjustment command. Also, the upper control device 8 may supply, for example, the measured values of the received power in a predetermined period among the stored measured values of the received power to the supply-demand adjustment device 20 instead of the predicted load power value. The predicted load power value is not limited to the above, and may be a value calculated by a learning model generated using, for example, information such as the measured values of past received power, weather, outside air temperature, and the number of railway users (actual users and expected numbers).

[0018] In this embodiment, the upper control device 8 calculates a charge / discharge power command value with the downward DR amount being positive and the upward DR amount being negative. The adjustment power value may be, for example, time series data of the adjustment amount (adjustment power) of the received power within the time zone when the supply-demand adjustment is performed.

[0019] Note that the baseline is determined through consultation between the power distribution company and the administrator of the consumer (DC power system 100). The setting of the baseline may be made with reference to the "Guidelines on Energy Resource Aggregation Business" issued by the Agency for Natural Resources and Energy, or may adopt, for example, a setting method called High 4 of 5. On a consumer-by-consumer basis, the average value of the actual demand volume in the 6 frames in 30-minute units before the supply-demand adjustment implementation time zone on the day of the supply-demand adjustment implementation (for example, from 4 hours before to 1 hour before) may be set as the baseline.

[0020] The power supply-demand adjustment device 20 is configured to be communicable with the upper control device 8 and the DC power system 100. The power supply-demand adjustment device 20 is, for example, a computing device (server device) including a processor and a memory storing a program executed by the processor, and can realize various functions described below by software or a combination of software and hardware.

[0021] When the power supply-demand adjustment device 20 receives an adjustment power value, a baseline, and a load power prediction value from the upper control device 8, it generates a target power reception value based on the adjustment power value and the baseline, and calculates a charge / discharge power value by taking the difference between the generated target power reception value and the load power prediction value. The power supply-demand adjustment device 20 can calculate a target power amount at a predetermined time by integrating (integrating) the calculated charge / discharge power value. The power supply-demand adjustment device 20 generates an SOC offset value (adjustment amount) corresponding to the charge / discharge power amount for power supply-demand adjustment so that the power storage medium 5 performs charge and discharge only by the value of the calculated target power amount, and transmits it to the power storage control unit 7 of the power storage device 4. Here, the power supply-demand adjustment device 20 is configured to calculate the target power reception based on the adjustment power value and the baseline from the upper control device 10, but it may also be configured to transmit the target power reception (or target power amount) in the power supply-demand adjustment execution time zone from the upper control device 10 as a power supply-demand adjustment command.

[0022] Note that the power supply-demand adjustment device 20 may charge and discharge the power storage medium 5 so that power supply-demand adjustment can be performed prior to the time zone in which the power supply-demand adjustment is implemented. The power supply-demand adjustment device 20 may forcibly charge the power storage medium 5 before the lowering DR that reduces the customer-side load by the power supply-demand adjustment, so that the power storage medium 5 can discharge the power amount by the power supply-demand adjustment in the power supply-demand adjustment execution time zone. Also, the power supply-demand adjustment device 20 may forcibly discharge the power storage medium 5 before the raising DR that increases the customer load by the power supply-demand adjustment, so that the power storage medium 5 can charge the power amount by the power supply-demand adjustment in the power supply-demand adjustment execution time zone.

[0023] The supply-demand adjustment device 20 transmits a control table selection command to the power storage control unit 7 of the power storage device 4 corresponding to whether or not supply-demand adjustment is to be performed and the time zone in which supply-demand adjustment is to be performed. For example, the supply-demand adjustment device 20 selects the normal grid connection table in a time zone where supply-demand adjustment and preparation for supply-demand adjustment are not being performed, selects the down DR execution table in a time zone where down DR is being executed, selects the up DR execution table in a time zone where up DR is being executed, selects the forced charge table in a time zone for performing preparation before down DR is executed, and selects the forced discharge table in a time zone for performing preparation before up DR is executed, and transmits a control table selection command to the power storage control unit 7.

[0024] In addition, the supply-demand adjustment device 20 acquires the rated capacity and the degree of degradation (SOH: state of health) of the power storage medium 5 from the power storage device 4, and calculates the available adjustment amount in the future (e.g., tomorrow) considering the system efficiency with respect to the effective battery capacity of the power storage medium 5 (rated capacity of the power storage medium 5 × SOH × charge / discharge margin) (the amount by which the customer-side load can be reduced (down DR amount), the amount by which the customer-side load can be increased (up DR amount)). The supply-demand adjustment device 20 transmits the calculated available adjustment amount to the upper control device 8 by a preset deadline. The configuration and operation of the supply-demand adjustment device 20 will be described later with reference to the drawings.

[0025] The power storage device 4 includes a power storage medium 5, a power converter 6, and a power storage control unit 7. The power storage medium 5 may include a power storage element capable of storing electrical energy, such as a secondary battery, a fuel cell, a capacitor, or a flywheel.

[0026] In the present embodiment, the power storage medium 5 includes at least one power storage module equipped with a battery pack including a plurality of rechargeable battery cells such as a lithium ion battery, a nickel hydrogen battery, or a lead storage battery, and a cell monitoring unit (CMU: Cell Monitoring Unit). The battery pack (not shown) includes, for example, 24 battery cells with 20 Ah battery cells connected in 2 parallel and 12 series.

[0027] The CMU (not shown) is configured to be communicable with the power storage control unit 7 described later, periodically measures the voltage and temperature of each battery cell (or battery pack) and the charge / discharge current of the power storage medium 5, and notifies the measurement results to the power storage control unit 7. The CMU may calculate the state of charge (SOC) and the degree of degradation (SOH) of the power storage medium 5 using the voltage and temperature of each battery cell (or battery pack) and the charge / discharge current of the power storage medium 5, and notify the calculation results to the power storage control unit 7. In this case, the CMU can calculate the SOC and SOH by a general calculation method.

[0028] The power converter 6 is electrically connected between the power storage medium 5 and the power circuit. The power converter 6 includes, for example, a DC / DC converter. The power converter 6 detects the voltage of the power supply line 1, and according to the values of the charge start voltage and the discharge start voltage supplied from the power storage control unit 7, converts the DC power discharged from the power storage medium 5 of the power storage medium 5 into DC power of a predetermined voltage and discharges it to the power circuit, and converts the regenerative power supplied from the power circuit into DC power of a predetermined voltage and charges the power storage medium 5. The charge start voltage is the voltage of the power circuit (power supply line 1) when the power storage medium 5 is charged. The discharge start voltage is the voltage of the power circuit (power supply line 1) when the power storage medium 5 is discharged. For example, the charge start voltage is the lower limit value of the voltage of the power circuit (power supply line 1) when the power storage medium 5 is charged. For example, the discharge start voltage is the upper limit value of the voltage of the power circuit (power supply line 1) when the power storage medium 5 is discharged.

[0029] Note that, without being limited thereto, any converter may be used for the power converter 6 according to the type of the power storage medium 5 and the power circuit. The power converter 6 may also include a current limiter that controls the limit value of the charge / discharge current.

[0030] The power storage control unit 7 includes, for example, an arithmetic circuit including at least one processor and a memory in which a program executed by the processor is recorded. The power storage control unit 7 is configured to be communicable with the supply-demand adjustment device 20, and based on the SOC offset command value supplied from the supply-demand adjustment device 20, and based on the voltage of the power receiving line 1 and the state of charge (SOC) of the power storage medium 5, controls the power converter 6 to charge and discharge the power storage medium 5.

[0031] The power storage control unit 7 is configured to be communicable with the power storage medium 5. The power storage control unit 7 acquires information of the power storage medium 5 such as the voltage, temperature of the battery cell (or battery pack) measured by the power storage medium 5, the value of the charge and discharge current of the power storage medium 5, the state of charge (SOC), and the degree of degradation (SOH) from the power storage medium 5. Note that the power storage control unit 7 may calculate the state of charge (SOC) and the degree of degradation (SOH) of the power storage medium 5 using values such as the voltage, charge and discharge current, and temperature acquired from the power storage medium 5.

[0032] Also, the power storage control unit 7 is configured to be communicable with the power converter 6 and transmits a control command to the power converter 6. The control command transmitted from the power storage control unit 7 to the power converter 6 may include, for example, the voltage of the power receiving line 1 (charge start voltage) for starting charging the power storage medium 5, the voltage of the power receiving line 1 (discharge start voltage) for starting discharging the power storage medium 5, the allowable current value that can flow through the power storage medium 5, the maximum discharge power value and the maximum charge power value that can be output from the power converter 6 to the power receiving circuit.

[0033] The power storage control unit 7 can adjust the discharge start voltage and the charge start voltage according to the state of charge (SOC) of the power storage medium 5. For example, if the state of charge (SOC) of the power storage medium 5 decreases, the discharge start voltage and the charge start voltage decrease. For example, if the state of charge (SOC) of the power storage medium 5 increases, the discharge start voltage and the charge start voltage increase. The charge and discharge control of the power storage medium 5 that adjusts the discharge start voltage and the charge start voltage in this way is called power receiving voltage - SOC control.

[0034] The power storage control unit 7 may execute the power voltage - SOC control according to a pre - set table of discharge start voltage·charge start voltage - SOC. In this case, the power storage control unit 7 stores a plurality of tables corresponding to a plurality of patterns of power voltage - SOC, selects a table based on a control table selection command from the power demand - supply adjustment device 20, and supplies the charge start voltage and the discharge start voltage with respect to the SOC of the power storage medium 5 to the power converter 6 using the selected table, thereby performing the power voltage - SOC control. In the present embodiment, the power storage control unit 7 includes at least five tables of discharge start voltage·charge start voltage - SOC, such as a normal grid connection table, a forced charge table, a forced discharge table, a lower DR execution table, and an upper DR execution table.

[0035] Next, an example of the configurations of the power demand - supply adjustment device 20 and the power storage control unit 7 in the power demand - supply adjustment system according to the present embodiment will be described.

[0036] FIG. 2 is a diagram schematically showing a configuration example of the power demand - supply adjustment device of the power demand - supply adjustment system shown in FIG. 1. The power demand - supply adjustment device 20 includes a control table selection unit 21, a subtraction unit 20A, an integration unit 20B, a gain multiplication unit 20C, and a division unit 20E.

[0037] The control table selection unit 21 outputs a control table selection command to the power storage control unit 7 according to, for example, the adjustment power value and the power demand - supply adjustment execution time zone. The control table selection unit 21 selects the normal grid connection table in a time zone when power demand - supply adjustment and preparation for power demand - supply adjustment are not performed, selects the lower DR execution table when the adjustment power value is negative and it is the power demand - supply adjustment execution time zone (lower DR execution time zone), selects the upper DR execution table when the adjustment power value is positive and it is the power demand - supply adjustment execution time zone (upper DR execution time zone), selects the forced charge table in a time zone for preparing before lower DR execution, and selects the forced discharge table in a time zone for preparing before upper DR execution, and transmits a control table selection command to the power storage control unit 7.

[0038] The demand-supply adjustment device 20 subtracts the adjustment power value from the baseline supplied from the upper control device 8 to calculate the value of the target received power (kW), and inputs it to the subtraction unit 20A. When the adjustment power value supplied from the upper control device 8 is the value of the amount of power to be adjusted for demand-supply adjustment in the time zone where demand-supply adjustment is carried out, the adjustment power value at each time may be calculated and used by using a mathematical formula or the like of the adjustment power value with respect to the time when the adjustment power amount is generated so as to be adjusted within the demand-supply adjustment execution time zone.

[0039] The subtraction unit 20A receives the value of the target received power (kW) and the load power prediction value (kW) received from the upper control device 8. The subtraction unit 20A calculates and outputs a charge-discharge power value that is the difference obtained by subtracting the load power prediction value from the value of the target received power.

[0040] The integration unit 20B calculates and outputs a value obtained by integrating the input charge-discharge power value. The integration unit 20B resets the integration value to zero for each preset period. In this embodiment, the integration unit 20B is set to reset the integration value every 30 minutes.

[0041] The gain multiplication unit 20C multiplies the value output from the integration unit 20B by the adjustment gain K to calculate and output the target power amount (kWh). Here, the target power amount is a value that adjusts the received power amount of the substation 10 by charging the power storage medium 5 when it is positive and discharging the power storage medium 5 when it is negative to adjust the load. By multiplying the difference output from the integration unit 20B by the adjustment gain K, it is possible to adjust so as to increase the responsiveness of the received power amount with respect to the target power amount.

[0042] The division unit 20E receives the value of the target power amount output from the gain multiplication unit 20C and the value of the effective battery capacity. The effective battery capacity is, for example, a value obtained by multiplying the rated capacity of the power storage medium 5 acquired from the power storage device 4 by the SOH (state of health) of the power storage medium 5 and considering the charge-discharge margin. The division unit 20E divides the target power amount by the effective battery capacity to calculate the SOC offset value, and outputs it to the power storage control unit 7.

[0043] The power storage control unit 7 receives a control table selection command and an SOC offset value from the supply-demand adjustment device 20. During the supply-demand adjustment execution time period, the power storage control unit 7 selects a table of discharge start voltage - charge start voltage - SOC based on the control table selection command, and adjusts the charge start voltage and discharge start voltage of the selected table by the SOC offset value. The power storage control unit 7 refers to the adjusted table, acquires the charge start voltage and discharge start voltage with respect to the SOC of the power storage medium 5, and transmits them to the power converter 6.

[0044] During the time period when the power storage control unit 7 makes preparations before executing the lowering DR, based on the control table selection command from the supply-demand adjustment device 20, it selects a forced charge table (table for lowering DR preparation) as a table of discharge start voltage - charge start voltage - SOC for performing power-on voltage - SOC control. The charge start voltage of the forced charge table is set to a value sufficiently lower than the normal power-on voltage so that the power storage medium 5 is forcibly charged from an SOC of 0% to near 100%. The discharge start voltage of the forced charge table is set to a value sufficiently lower than the normal power-on voltage in the range where the SOC of the power storage medium 5 is from 0% to near 100%, and is set to suppress the discharge of the power storage medium 5.

[0045] FIG. 3 is a diagram schematically showing an example of a table of discharge start voltage - charge start voltage - SOC used in power-on voltage - SOC control when the lowering DR is executed. FIG. 3 shows an example of the lowering DR execution table possessed by the power storage control unit 7. The lowering DR execution table includes information on the correspondence between the SOC of the power storage medium 5 and the power-on voltage at which discharge starts, and information on the correspondence between the SOC of the power storage medium 5 and the power-on voltage at which charging starts. During the execution of the lowering DR, the charge start voltage is set to maintain a value capable of charging the regenerative power from the power-on circuit from an SOC of 0% to near 100% of the power storage medium 5. Also, during the execution of the lowering DR, the discharge start voltage can be set to a value lower than the normal power-on voltage in the range where the SOC of the power storage medium 5 is from 0% to near 100%.

[0046] When the power storage control unit 7 receives a control table selection command to select a reduction DR execution table from the supply-demand adjustment device 20, it selects, for example, the reduction DR execution table shown in FIG. 3 as a table of discharge start voltage - charge start voltage - SOC for performing power storage voltage - SOC control.

[0047] The power storage control unit 7 adjusts the discharge start voltage of the selected reduction DR execution table according to the SOC offset value. For example, the power storage control unit 7 shifts the SOC at which the line of the discharge start voltage of the reduction DR execution table rises by the SOC offset value. When the SOC offset value is negative, the SOC at which the line of the discharge start voltage rises becomes smaller, and power storage voltage - SOC control is performed so that the discharge of the power storage medium 5 proceeds. When the SOC offset value is positive, the SOC at which the line of the discharge start voltage rises becomes larger, and power storage voltage - SOC control is performed so that the discharge of the power storage medium 5 is suppressed.

[0048] Note that the amount by which the power storage control unit 7 adjusts the rising position of the discharge start voltage line is not limited to the SOC offset value, and may be a value set based on the SOC offset value. Further, the power storage control unit 7 may adjust at least one of the rising position of the charge start voltage line and the rising position of the discharge start voltage line of the reduction DR execution table according to the SOC offset value, or may adjust the rising position of the charge start voltage line of the reduction DR execution table according to the SOC offset value.

[0049] During the time period when the power storage control unit 7 performs preparations before the execution of the increase DR, based on the control table selection command, it selects a forced discharge table (table for increase DR preparation) as a table of discharge start voltage - charge start voltage - SOC for performing power storage voltage - SOC control. The charge start voltage of the forced discharge table is set to a voltage that can always charge regenerative power from when the SOC of the power storage medium 5 is near 0% to near 100%. The discharge start voltage of the forced discharge table is set to a value sufficiently higher than the normal power storage voltage in the range where the SOC of the power storage medium 5 is from near 0% to 100%, and is set so that the discharge of the power storage medium 5 proceeds forcibly.

[0050] FIG. 4 schematically shows an example of a table of discharge start voltage - charge start voltage - SOC used in the boost DR execution voltage - SOC control when boost DR is executed. FIG. 4 shows an example of the boost DR execution table included in the power storage control unit 7. The boost DR execution table includes information on the correspondence between the SOC of the power storage medium 5 and the threshold voltage at which discharge is started, and information on the correspondence between the SOC of the power storage medium 5 and the threshold voltage at which charging is started.

[0051] When boost DR is executed, the pre - adjustment charge start voltage is set to a value at which the regenerative power from the threshold circuit is not charged as the SOC of the power storage medium 5 ranges from near 0% to 100%. Also, when boost DR is executed, the pre - adjustment discharge start voltage is set to a value that suppresses the discharge of the power storage medium 5 in the range where the SOC of the power storage medium 5 is from near 0% to 100%.

[0052] When the power storage control unit 7 receives a control table selection command to select the boost DR execution table from the demand - supply adjustment device 20, it selects, for example, the boost DR execution table shown in FIG. 4 as the table of discharge start voltage - charge start voltage - SOC for performing the threshold voltage - SOC control.

[0053] The power storage control unit 7 adjusts the discharge start voltage and the charge start voltage of the selected boost DR execution table according to the SOC offset value. For example, the power storage control unit 7 shifts the SOC at which the line of the discharge start voltage of the boost DR execution table rises by the SOC offset value. When the SOC offset value is negative, the SOC at which the line of the discharge start voltage rises becomes smaller, and the threshold voltage - SOC control is performed so as to suppress the discharge of the power storage medium 5. When the SOC offset value is positive, the SOC at which the line of the discharge start voltage rises becomes larger, and the threshold voltage - SOC control is performed so that the discharge of the power storage medium 5 proceeds.

[0054] When the SOC offset value is negative, the charge voltage - SOC control is performed such that the SOC at which the charge start voltage line rises becomes smaller, and the charging of the power storage medium 5 is suppressed. When the SOC offset value is positive, the charge voltage - SOC control is performed such that the SOC at which the charge start voltage line rises becomes larger, and the charging of the power storage medium 5 proceeds.

[0055] Note that the amount by which the power storage control unit 7 adjusts the rising positions of the discharge start voltage and charge start voltage lines is not limited to the SOC offset value, and may be a value set based on the SOC offset value. Further, the power storage control unit 7 may adjust at least one of the rising position of the charge start voltage line and the rising position of the discharge start voltage line in the charge start voltage execution table according to the SOC offset value.

[0056] Next, an example of the operation in the supply - demand adjustment execution time zone of the power supply - demand adjustment system of the present embodiment will be described.

[0057] FIG. 5 is a flowchart for explaining an example of the operation of the power supply - demand adjustment system of the present embodiment. The flowchart of FIG. 5 shows an example of the operation of the supply - demand adjustment device 20 in the supply - demand adjustment execution time zone.

[0058] The supply - demand adjustment device 20 calculates a target received power (= baseline - adjustment power) using the values of the adjustment power supplied from the upper - level control device 8 and the baseline (step S1).

[0059] Subsequently, the supply - demand adjustment device 20 acquires a load power prediction value from the upper - level control device 8 (step S2). Also, when the supply - demand adjustment device 20 has been supplied with a measured value of the received power from the upper - level control device 8, for example, it calculates the load power prediction value from the supplied measured value. Note that the order of the processes in step S1 and step S2 is not limited to this. The supply - demand adjustment device 20 may calculate the target received power after calculating the load power prediction value.

[0060] The power supply and demand adjustment device 20 obtains a charge / discharge power value (= target power reception - predicted load power) based on the calculated target power reception and the predicted load power value, and calculates a target power amount by integrating the charge / discharge power value and multiplying by a gain (step S3).

[0061] The power supply and demand adjustment device 20 divides the calculated target power amount by the effective battery capacity to calculate an SOC offset value (step S4), and transmits the calculated SOC offset value to the power storage control unit 7 of the power storage device 4 (step S5).

[0062] The power supply and demand adjustment device 20 determines whether or not a predetermined time has elapsed since the integral value was reset last time, and repeats steps S1 to S7 above until the predetermined time elapses (step S6, NO). When the power supply and demand adjustment device 20 determines that the predetermined time has elapsed since the integral value was reset (step S6, YES), it resets the integral value of the charge / discharge power value to zero (step S7) and starts counting the predetermined time. The power supply and demand adjustment device 20 repeats steps S1 to S7 above during the power supply and demand adjustment execution time period.

[0063] The power storage control unit 7 selects a discharge start voltage - charge start voltage - SOC table for performing voltage - SOC control according to the control table selection command supplied from the power supply and demand adjustment device 20, and transmits the values of the charge start voltage and the discharge start voltage with respect to the SOC of the power storage medium 5 to the power converter 6 using the selected table.

[0064] As described above, in the power supply and demand adjustment system of this embodiment, the upper control device 8 acquires a supply and demand adjustment plan including the adjustment power and reference value in the supply and demand adjustment execution time zone, and the predicted load power value of the substation 10, and uses the target power amount obtained by integrating the charge and discharge power value, which is the difference between the predicted load power value of the substation 10 and the target received power based on the adjustment power and reference value, to generate an SOC offset value for adjusting the received power amount from the AC power supply. In the supply and demand adjustment execution time zone, based on the voltage of the power generation circuit, the SOC offset value, and the charge state of the power storage medium 5, the regenerative power from the power generation circuit is charged to the power storage medium 5, and the discharge power of the power storage medium 5 is supplied to the power generation line 1.

[0065] Also, in the power supply and demand adjustment system of this embodiment, since the integrated value of the target power amount is reset simultaneously every predetermined time, it becomes easy to evaluate whether the supply and demand adjustment is accurately performed every predetermined time.

[0066] Thus, according to the power supply and demand adjustment system of this embodiment, by integrating the charge and discharge power value based on the command from the upper control device 8 and calculating the target power amount for a predetermined time, it is possible to charge and discharge the power amount of the intended value to the power storage device 4, and accurate supply and demand adjustment can be performed.

[0067] Also, the DC power generation system 100 may be a system including a plurality of substations 10. In that case, the upper control device 8 measures the received power of the plurality of substations 10 from the AC power supply, and generates a predicted load power value based on the measured received power value.

[0068] The program according to this embodiment may be transferred in a state stored in an electronic device, or may be transferred in a state not stored in an electronic device. In the latter case, the program may be transferred via a network, or may be transferred in a state stored in a storage medium. The storage medium is a non-temporary tangible medium. The storage medium is a computer-readable medium. The storage medium may be any medium that can store a program such as a CD-ROM or a memory card and is readable by a computer, regardless of its form.

[0069] Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0070] 100…DC power system, 1…Power line, 2…Return line, 3…Electric vehicle, 4…Power storage device, 5…Power storage medium, 6…Power converter, 7…Power storage control unit, 8…Upper control device, 9…Electric energy meter, 10…Substation, 11…Transformer, 12…Rectifier, 13…Transformer, 20…Supply-demand adjustment device, 20A…Subtraction unit, 20B…Integration unit, 20C…Gain multiplication unit, 20E…Division unit, 21…Control table selection unit

Claims

1. A system for adjusting the received power amount of a substation that supplies DC power obtained by rectifying AC power supplied from an AC power source to a power supply circuit, comprising: a power supply and demand adjustment device that acquires a power supply and demand adjustment command including adjustment power and a reference value in a power supply and demand adjustment execution time period and a predicted load power value of the substation, calculates a charge and discharge power value that is the difference between the predicted load power value of the substation and a target received power based on the adjustment power and the reference value, and generates an adjustment amount for adjusting the received power amount from the AC power source using a target power amount based on the charge and discharge power value; a power storage device including a power storage medium, and during the power supply and demand adjustment execution time period, charging the power storage medium with regenerative power from the power supply circuit and supplying discharge power of the power storage medium to the power supply circuit based on the voltage of the power supply circuit, the adjustment amount, and the charge state of the power storage medium; A power supply and demand adjustment system comprising the above.

2. A system for adjusting the received power amount of a substation that supplies DC power obtained by rectifying AC power supplied from an AC power source to a power supply circuit, comprising: a power supply and demand adjustment device that acquires a power supply and demand adjustment command including a target received power in a power supply and demand adjustment execution time period and a predicted load power value of the substation, calculates a charge and discharge power value that is the difference between the predicted load power value of the substation and the target received power, and generates an adjustment amount for adjusting the received power amount from the AC power source using a target power amount based on the charge and discharge power value; a power storage device including a power storage medium, and during the power supply and demand adjustment execution time period, charging the power storage medium with regenerative power from the power supply circuit and supplying discharge power of the power storage medium to the power supply circuit based on the voltage of the power supply circuit, the adjustment amount, and the charge state of the power storage medium; A power supply and demand adjustment system comprising the above.

3. The power supply and demand adjustment system is communicable with a higher-level control device that measures the received power of the AC power source, and the power supply and demand adjustment device acquires the predicted load power value, which is a predicted value of the load power of the substation generated based on the measured value of the received power, from the higher-level control device. The power supply and demand adjustment system according to Claim 1 or Claim 2.

4. The power supply and demand adjustment device outputs a control table selection command according to the power supply and demand adjustment execution time period and the value of the adjustment amount. The power storage device includes a plurality of tables including the voltage of the power conversion circuit that charges the power storage medium with respect to the state of charge of the power storage medium, and the voltage of the power conversion circuit that discharges the power storage medium with respect to the state of charge of the power storage medium. Using the table selected according to the control table selection command, the power supplied from the power conversion circuit is charged to the power storage medium according to the state of charge of the power storage medium and the voltage of the power conversion circuit, and the power discharged from the power storage medium is supplied to the power conversion circuit. The power supply and demand adjustment system according to claim 3.

5. The power storage device adjusts at least one of a lower limit value of the voltage of the power conversion circuit that charges the power storage medium with respect to the state of charge of the power storage medium and an upper limit value of the voltage of the power conversion circuit that discharges the power storage medium with respect to the state of charge of the power storage medium according to the adjustment amount during the supply and demand adjustment execution time period. The power supply and demand adjustment system according to claim 4.

6. The received power amount of the AC power supply is the sum of the power amount supplied from the AC power supply to the power conversion circuit and the power amount consumed by other AC loads included in the substation. The power supply and demand adjustment system according to claim 1 or claim 2.

7. The power storage medium is a secondary battery. The power supply and demand adjustment system according to claim 1 or claim 2.

8. A system including a plurality of the substations, The load power prediction value is generated based on the measured values of the received power of the plurality of substations from the AC power supply. The power supply and demand adjustment system according to claim 3.

9. A method for adjusting the received power amount of a substation that supplies DC power obtained by rectifying AC power supplied from an AC power supply to a power conversion circuit, Obtain a supply and demand adjustment command including adjustment power and a reference value during the supply and demand adjustment execution time period and the load power prediction value of the substation, calculate a charge and discharge power value that is the difference between the load power prediction value of the substation and the target received power based on the adjustment power and the reference value, and use the target power amount based on the charge and discharge power value to generate an adjustment amount for adjusting the received power amount from the AC power supply. During the supply and demand adjustment execution time period, based on the voltage of the power conversion circuit, the adjustment amount, and the state of charge of the power storage medium, the regenerative power from the power conversion circuit is charged to the power storage medium and the discharge power of the power storage medium is supplied to the power conversion circuit. A power supply and demand adjustment method.

10. A method for adjusting the received power amount of a substation that supplies DC power obtained by rectifying AC power supplied from an AC power source to a power supply circuit, comprising: Obtaining a supply-demand adjustment command including a target received power amount in a supply-demand adjustment execution time period and a predicted load power value of the substation, calculating a charge-discharge power value that is the difference between the predicted load power value of the substation and the target received power amount, and using a target power amount based on the charge-discharge power value to generate an adjustment amount for adjusting the received power amount from the AC power source; A power supply-demand adjustment method for charging the regenerative power from the power supply circuit to the power storage medium and supplying the discharge power of the power storage medium to the power supply circuit based on the voltage of the power supply circuit, the adjustment amount, and the charge state of the power storage medium in the supply-demand adjustment execution time period.

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