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 comprises: a supply and demand adjustment device 22 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 generates an adjustment amount for adjusting the amount of power to be received from an AC power supply so that a feedback value of the amount of power received by a substation 13 from the AC power supply follows a target amount of received power based on the adjustment power and the reference value; and a power storage device 4 that includes a power storage medium 5, charges the power storage medium 5 with electric power supplied from a feeding circuit on the basis of the adjustment amount, the state of charge of the power storage medium 5 and the voltage of the feeding circuit in the supply and demand adjustment execution time zone, and supplies the electric power discharged from the power storage medium 5 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] For example, in an electric railway system, even if trains are operated according to the same train schedule, the power consumption of the electric railway system varies from day to day. The variation in power consumption is caused by factors such as fluctuations in passenger demand, fluctuations in auxiliary equipment load, and changes in the consumption of high-voltage power distribution loads such as stations and signal facilities. Even if the charge and discharge of a planned energy storage device are carried out according to the time, it is difficult to accurately control the power demand of the electric railway and to supply 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] A power supply-demand adjustment system according to an 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 generation circuit, and obtains a supply-demand adjustment command including adjustment power and a reference value in a supply-demand adjustment execution time zone. A supply-demand adjustment device that generates an adjustment amount for adjusting the received power amount from the AC power source so that the feedback value of the received power amount received by the substation from the AC power source follows a target received power amount based on the adjustment power and the reference value; and a power storage medium, and in the supply-demand adjustment execution time zone, based on the adjustment amount, the charge state of the power storage medium, and the voltage of the power generation circuit, the power supplied from the power generation circuit is charged to the power storage medium, and the power discharged from the power storage medium is supplied to the power generation circuit. A power storage device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

[0011] Hereinafter, a power supply / demand adjustment system and a power supply / demand adjustment method according to an embodiment will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a configuration example of the power supply / demand adjustment system according to the first embodiment. In the present embodiment, as an example, a power supply / 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 line 1 and a return line 2. The return line 2 is, for example, a rail on which the electric vehicle 3 travels. The DC power supply system 100 is grounded by the return line 2.

[0012] The power supply / demand adjustment system of the present embodiment includes a host control device 10, a supply / demand adjustment device 22, a substation 13, and a power storage device 4. The substation 13 is electrically connected between an AC power supply system (not shown) and an electric circuit (including the live wire 1 and the return wire 2). The substation 13 includes a watt-hour meter 15, a first transformer 16, a second transformer 18, and a rectifier 17.

[0013] The watt-hour meter 15 measures the received power consumption of the substation 13 from an AC power supply system not shown. The watt-hour meter 15 may be a watt-hour meter that outputs and counts pulses for each unit of power consumption. The measured value of the watt-hour meter 15 is supplied to a supply-demand adjustment device 22 described later.

[0014] The first transformer 16 converts and outputs the voltage of the AC power received from the AC power supply system. The rectifier 17 outputs the DC power obtained by rectifying the AC power output from the first transformer 16 to the electric circuit. The second transformer 18 converts the voltage of the AC power received from the AC power supply system and outputs the AC power that serves as the power supply for AC loads, signal facilities, stations, etc. within the substation.

[0015] The upper control device 10 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 22 described later and bids in the supply-demand adjustment market. The available adjustment amounts 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 10 receives an upper supply-demand adjustment command from the distribution utility on the day of supply-demand adjustment. The upper supply-demand adjustment command from the distribution utility is notified to the upper control device 10 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 10 creates a supply-demand adjustment command according to the upper supply-demand adjustment command. The supply-demand adjustment command may include an adjustment 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 13 assumed in the case where there is no supply-demand adjustment command), and the supply-demand adjustment implementation time zone. The upper control device 10 supplies the generated supply-demand adjustment command to the supply-demand adjustment device 22.

[0016] In this embodiment, the upper control device 10 calculates an adjustment power value with the lowering DR amount being positive and the raising DR amount being negative. The adjustment power value may be set, for example, as the value of the amount of power to be adjusted for demand-supply adjustment over the entire time period during which demand-supply adjustment is performed, or may be time-series data of the adjustment amount (adjustment power) of the received power within the time period during which demand-supply adjustment is performed.

[0017] Note that the baseline is determined through consultation between the power distribution business operator 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 for example, the setting method called High 4 of 5 may be adopted. On a per-consumer basis, the average value of the actual demand amount in the time period before the demand-supply adjustment execution time period on the day of demand-supply adjustment execution (for example, 6 frames in 30-minute units from 4 hours before to 1 hour before) may be set as the baseline.

[0018] The demand-supply adjustment device 22 is configured to be communicable with the upper control device 10 and the DC power system 100. The demand-supply adjustment device 22 is, for example, an arithmetic 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.

[0019] The power demand adjustment device 22 receives an adjustment power value, a baseline, and a power demand adjustment execution time from the upper control device 10, obtains the measured value of the received power of the substation 13 from the watt-hour meter 15, and integrates (integrates) the measured values for a predetermined time to calculate the actual received power amount at the predetermined time. The power demand adjustment device 22 uses the actual received power amount as a feedback value, calculates the difference between the target received power amount based on the adjustment power value and the baseline and the feedback value, and generates an SOC offset value (adjustment amount) corresponding to the charge and discharge power amount for power demand adjustment so that the difference becomes zero (so that the feedback value follows the target received power amount), and transmits it to the power storage control unit 7 of the power storage device 4. Here, the power demand adjustment device 22 is configured to calculate the target received power (kW) based on the adjustment power value and the baseline from the upper control device 10. However, it may also be configured to transmit the target received power (kW) (or target received power amount (kWh)) in the power supply and demand adjustment execution time zone from the upper control device 10 as a power supply and demand adjustment command. The power demand adjustment device 22 may calculate the target received power (kW) from the target received power amount (kWh) and input it to the integrator 22A.

[0020] Note that the power demand adjustment device 22 may charge and discharge the power storage medium 5 prior to the time zone in which the power demand adjustment is carried out so that the power demand adjustment can be performed. The power demand adjustment device 22 may forcibly charge the power storage medium 5 before the downward DR that reduces the customer-side load by the power demand adjustment, and prepare so that the power storage medium 5 can discharge the power amount due to the power demand adjustment in the power demand adjustment execution time zone. Also, the power demand adjustment device 22 may forcibly discharge the power storage medium 5 before the upward DR that increases the customer load by the power demand adjustment, and prepare so that the power storage medium 5 can charge the power amount due to the power demand adjustment in the power demand adjustment execution time zone.

[0021] The supply-demand adjustment device 22 transmits a control table selection command to the power storage control unit 7 of the power storage device 4 corresponding to whether supply-demand adjustment is carried out and the time zone in which supply-demand adjustment is carried out. For example, the supply-demand adjustment device 22 selects the normal grid connection table in a time zone where supply-demand adjustment and preparation for supply-demand adjustment are not carried out, 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 preparing before down DR is executed, and selects the forced discharge table in a time zone for preparing before up DR is executed, and transmits a control table selection command to the power storage control unit 7.

[0022] In addition, the supply-demand adjustment device 22 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 adjustable amount that can be provided in the future (for example, 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 22 transmits the calculated adjustable amount to the upper control device 10 by a preset deadline.

[0023] The configuration and operation of the supply-demand adjustment device 22 will be described later with reference to the drawings. 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.

[0024] 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 connected in 2 parallel and 12 series of 20 Ah battery cells.

[0025] CMU (not shown) is configured to be communicable with a power storage control unit 7 described later, periodically measures the voltage and temperature of each battery cell (or battery pack) and the charge and 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 and 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.

[0026] 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 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. The charge start voltage is, for example, the lower limit value of the voltage of the power circuit (power supply line 1) when the power storage medium 5 is charged. The discharge start voltage is, for example, the upper limit value of the voltage of the power circuit (power supply line 1) when the power storage medium 5 is discharged.

[0027] Note that, without being limited to this, 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 and discharge current.

[0028] 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 22, and based on the voltage of the power receiving wire 1 and the state of charge (SOC) of the power storage medium 5 based on the SOC offset value supplied from the supply-demand adjustment device 22, controls the power converter 6 to charge and discharge the power storage medium 5.

[0029] 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.

[0030] 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 wire 1 (charge start voltage) to start charging the power storage medium 5, the voltage of the power receiving wire 1 (discharge start voltage) to start 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.

[0031] 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 the boost voltage-SOC control. The power storage control unit 7 may execute the boost voltage-SOC control according to a pre-set table of the 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 the boost voltage-SOC, selects a table based on a control table selection command from the demand-supply adjustment device 22, and uses the selected table to supply the charge start voltage and the discharge start voltage for the SOC of the power storage medium 5 to the power converter 6, and can perform the boost voltage-SOC control. In the present embodiment, the power storage control unit 7 includes at least five tables of the 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.

[0032] Next, an example of the configuration of the demand-supply adjustment device 22 and the power storage control unit 7 of the power demand-supply adjustment system according to the first embodiment will be described. FIG. 2 is a diagram schematically showing a configuration example of a demand-supply adjustment device of the power demand-supply adjustment system shown in FIG. 1. The demand-supply adjustment device 22 includes a control table selection unit 220, integration units 22A and 22D, a subtraction unit 22B, a gain multiplication unit 22C, and a division unit 22E.

[0033] The control table selection unit 220 outputs a control table selection command corresponding to, for example, the adjusted power value and the supply-demand adjustment execution time zone to the power storage control unit 7. The control table selection unit 220 selects the normal grid connection table during the time zone when supply-demand adjustment and preparation for supply-demand adjustment are not performed, selects the down DR execution table when the adjusted power value is negative and it is the supply-demand adjustment execution time zone (down DR execution time zone), selects the up DR execution table when the adjusted power value is positive and it is the supply-demand adjustment execution time zone (up DR execution time zone), selects the forced charge table during the time zone for preparing before down DR execution, and selects the forced discharge table during the time zone for preparing before up DR execution, and transmits a control table selection command to the power storage control unit 7.

[0034] The supply-demand adjustment device 22 subtracts the adjusted power value from the baseline supplied from the upper control device 10 to calculate the value of the target received power (kW) and inputs it to the integration unit 22A. When the adjusted power value supplied from the upper control device 10 is the value of the amount of power to be supply-demand adjusted during the time zone when supply-demand adjustment is performed, the adjusted power value at each time may be calculated and used using a mathematical formula or the like for the adjusted power value with respect to the time when the adjusted power amount is generated to be adjusted within the supply-demand adjustment execution time zone.

[0035] The integration unit 22A calculates and outputs the value of the target received power amount (kWh) obtained by integrating the input value of the target received power. The integration unit 22A resets the integration value to zero every preset period. In the present embodiment, the integration unit 22A is set to reset the integration value every 30 minutes.

[0036] The value of the received power amount (ΔWh) of the substation 13 measured by the watt-hour meter 15 is input to the integration unit 22D. The integration unit 22D calculates and outputs the feedback value (kWh) obtained by integrating the input value of the received power amount. The integration unit 22D is synchronized with the integration unit 22A in time and resets the integration value to zero every preset period. In the present embodiment, the integration unit 22D is set to reset the integration value every 30 minutes. Therefore, the output value of the integration unit 22A and the output value of the integration unit 22D are reset simultaneously and become zero.

[0037] The subtraction unit 22B receives the value of the target power reception amount (kWh) output from the integration unit 22A and the feedback value (kWh) output from the integration unit 22D. The subtraction unit 22B calculates and outputs the difference obtained by subtracting the feedback value (kWh) from the value of the target power reception amount (kWh).

[0038] The gain multiplication unit 22C multiplies the difference output from the subtraction unit 22B by the adjustment gain K to calculate and output the power supply-demand adjustment power amount. Here, the power supply-demand adjustment power amount is a value for adjusting the power reception amount of the substation 13 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 subtraction unit 22B by the adjustment gain K, it can be adjusted to increase the responsiveness of the power reception amount to the target power reception amount.

[0039] The division unit 22E receives the value of the power supply-demand adjustment power amount output from the gain multiplication unit 22C 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 22E divides the power supply-demand adjustment power amount by the effective battery capacity to calculate the SOC offset value and outputs it to the power storage control unit 7.

[0040] The power storage control unit 7 receives a control table selection command and the SOC offset value from the power supply-demand adjustment device 22. During the power supply-demand adjustment execution time period, the power storage control unit 7 selects a discharge start voltage - charge start voltage - SOC table based on the control table selection command, and adjusts the charge start voltage and the discharge start voltage of the selected table according to the SOC offset value. The power storage control unit 7 refers to the adjusted table, acquires the charge start voltage and the discharge start voltage with respect to the SOC of the power storage medium 5, and transmits them to the power converter 6.

[0041] During the time period for preparing before the execution of the downward DR, the power storage control unit 7 selects a forced charging table (a table for downward DR preparation) as a table of the discharge start voltage · charge start voltage - SOC for performing power supply - SOC control based on the control table selection command from the supply - demand adjustment device 22. The charge start voltage of the forced charging table is set to a value sufficiently lower than the normal power supply voltage so that the charge of the power storage medium 5 is forcibly performed from when the SOC of the power storage medium 5 is near 0% to 100%. The discharge start voltage of the forced charging table is set to a value sufficiently lower than the normal power supply voltage in the range where the SOC of the power storage medium 5 is from 0% to near 100%, and is set so that the discharge of the power storage medium 5 is suppressed.

[0042] FIG. 3 is a diagram schematically showing an example of a table of the discharge start voltage · charge start voltage - SOC used for power supply - SOC control when the downward DR is executed. FIG. 3 shows an example of the downward DR execution table possessed by the power storage control unit 7. The downward DR execution table includes information on the correspondence between the SOC of the power storage medium 5 and the power supply voltage at which discharge starts, and information on the correspondence between the SOC of the power storage medium 5 and the power supply voltage at which charging starts. During the execution of the downward DR, the charge start voltage is set to maintain a value capable of charging the regenerative power from the power supply circuit from when the SOC of the power storage medium 5 is near 0% to 100%. Also, during the execution of the downward DR, the discharge start voltage can be set to a value lower than the normal power supply voltage in the range where the SOC of the power storage medium 5 is from 0% to near 100%.

[0043] When the power storage control unit 7 receives a control table selection command from the supply - demand adjustment device 22 to select the downward DR execution table, it selects, for example, the downward DR execution table shown in FIG. 3 as a table of the discharge start voltage · charge start voltage - SOC for performing power supply - SOC control.

[0044] The power storage control unit 7 adjusts the discharge start voltage of the selected down 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 down 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 power supply 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 the power supply voltage - SOC control is performed so that the discharge of the power storage medium 5 is suppressed.

[0045] 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 down DR execution table according to the SOC offset value, or may adjust the rising position of the charge start voltage line of the down DR execution table according to the SOC offset value.

[0046] During the time period when the power storage control unit 7 performs preparations before the up DR execution, based on the control table selection command, it selects a forced discharge table (up DR preparation table) as a table of the discharge start voltage · charge start voltage - SOC for performing the power supply voltage - SOC control. The charge start voltage of the forced discharge table is set to a voltage at which regenerative power can always be charged from when the SOC of the power storage medium 5 is 0% to near 100%. The discharge start voltage of the forced discharge table is set to a value sufficiently higher than the normal power supply 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.

[0047] FIG. 4 is a diagram schematically showing an example of a table of the discharge start voltage · charge start voltage - SOC used in the power supply voltage - SOC control when the up DR is executed. FIG. 4 shows an example of the boosting DR execution table included in the power storage control unit 7. The boosting DR execution table includes information on the correspondence between the SOC of the power storage medium 5 and the threshold voltage at which discharging starts, and information on the correspondence between the SOC of the power storage medium 5 and the threshold voltage at which charging starts.

[0048] During the execution of boosting DR, the pre-adjustment charging start voltage is set to a value at which the regenerative power from the power generation circuit is not charged as the SOC of the power storage medium 5 ranges from near 0% to 100%. Also, during the execution of boosting DR, the pre-adjustment discharging start voltage is set to a value at which the discharging of the power storage medium 5 is suppressed within the range where the SOC of the power storage medium 5 ranges from near 0% to 100%.

[0049] When the power storage control unit 7 receives a control table selection command from the supply-demand adjustment device 22 to select the boosting DR execution table, it selects, for example, the boosting DR execution table shown in FIG. 4 as a table of the discharging start voltage and charging start voltage - SOC for performing power generation voltage - SOC control.

[0050] The power storage control unit 7 adjusts the discharging start voltage and charging start voltage of the selected boosting 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 discharging start voltage of the boosting DR execution table rises by the SOC offset value. When the SOC offset value is negative, the SOC at which the line of the discharging start voltage rises becomes smaller, and power generation voltage - SOC control is performed so that the discharging of the power storage medium 5 is suppressed. When the SOC offset value is positive, the SOC at which the line of the discharging start voltage rises becomes larger, and power generation voltage - SOC control is performed so that the discharging of the power storage medium 5 proceeds.

[0051] Also, when the SOC offset value is negative, the SOC at which the line of the charging start voltage rises becomes smaller, and power generation voltage - SOC control is performed so that the charging of the power storage medium 5 is suppressed. When the SOC offset value is positive, the SOC at which the line of the charging start voltage rises becomes larger, and power generation voltage - SOC control is performed so that the charging of the power storage medium 5 proceeds. Note that the amount by which the power storage control unit 7 adjusts the rising positions of the lines of the discharge start voltage and the charge start voltage 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 line of the charge start voltage and the rising position of the line of the discharge start voltage in the charge DR execution table according to the SOC offset value.

[0052] As described above, in the power supply and demand adjustment system of the present embodiment, the feedback value obtained by integrating the detected value of the received power amount received by the substation 13 from the AC power supply follows the target received power amount obtained by integrating the target received power based on the adjustment power and the reference value. Thus, an SOC offset value (adjustment amount) for adjusting the received power amount from the AC power supply is generated. During the supply and demand adjustment execution time period, based on the SOC offset value, the SOC of the power storage medium 5, and the voltage of the power generation circuit, the power supplied from the power generation circuit is charged to the power storage medium 5, and the power discharged from the power storage medium 5 to the power generation circuit is supplied to the power generation circuit. Accordingly, according to the power supply and demand adjustment system of the present embodiment, the power storage device 4 can be controlled by the power generation voltage - SOC so that the received power of the substation 13 follows the target received power amount considering the adjustment power, and accurate supply and demand adjustment can be performed.

[0053] Next, an example of the operation in the supply and demand adjustment execution time period of the power supply and demand adjustment system of the first embodiment will be described. FIG. 5 is a flowchart for explaining an example of the operation of the power supply and demand adjustment system of the first embodiment. The flowchart of FIG. 5 shows an example of the operation of the supply and demand adjustment device 22 in the supply and demand adjustment execution time period.

[0054] The supply and demand adjustment device 22 calculates the target received power (= baseline - adjustment power) using the values of the adjustment power supplied from the upper control device 10 and the baseline. Further, the supply and demand adjustment device acquires the received power amount of the substation 13 from the wattmeter 15 (step S1).

[0055] Subsequently, the supply-demand adjustment device 22 calculates the supply-demand adjustment power amount by multiplying the gain by the difference between the target received power amount obtained by integrating the target received power and the feedback value obtained by integrating the substation received power amount (step S2).

[0056] The supply-demand adjustment device 22 divides the calculated supply-demand adjustment power amount by the effective battery capacity to calculate the SOC offset value (step S3), and transmits the calculated SOC offset value to the power storage control unit 7 of the power storage device 4 (step S4).

[0057] The supply-demand adjustment device 22 determines whether or not a predetermined time has elapsed since the integral value was reset last time, and repeats the above steps S1 to S4 until the predetermined time elapses (step S5, NO). When the supply-demand adjustment device 22 determines that the predetermined time has elapsed since the integral value was reset (step S5, YES), it resets the integral value of the target received power and the substation received power amount to zero (step S6), and starts counting the predetermined time.

[0058] The power storage control unit 7 selects a table of the discharge start voltage - charge start voltage - SOC for performing voltage - SOC control according to the control table selection command supplied from the supply-demand adjustment device 22, 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.

[0059] FIG. 6 is a diagram for explaining an example of the effect of the power supply-demand adjustment system according to the first embodiment. FIG. 6 shows an example of the time change of the target received power amount and the substation received power amount calculated in the supply-demand adjustment device 22 of the power supply-demand adjustment system according to the first embodiment. The target received power is the power consumption based on the supply-demand adjustment plan generated in the upper control device 10, and changes from moment to moment.

[0060] In the power supply and demand adjustment system of this embodiment, charge and discharge of the power storage medium 5 are performed by voltage-SOC control using the SOC offset value calculated so that the substation received power amount follows the target received power amount (so that the difference between the substation received power amount and the target received power amount becomes zero). As a result, the received power amount of the substation 13 will substantially match the target received power amount. Therefore, according to the power supply and demand adjustment system and the power supply and demand adjustment method of this embodiment, by adjusting the customer load by performing charge and discharge of the power storage medium 5 during the supply and demand adjustment execution time zone, accurate power supply and demand adjustment can be performed.

[0061] Moreover, in the power supply and demand adjustment system of this embodiment, since the integrated value of the substation received power amount and the target received power amount are reset simultaneously every predetermined time, it becomes easy to evaluate whether the supply and demand adjustment has been accurately performed every predetermined time.

[0062] Next, the power supply and demand adjustment system and the power supply and demand adjustment method of the second embodiment will be described in detail with reference to the drawings. In the following description, the same components as those of the first embodiment described above are denoted by the same reference numerals and the description thereof is omitted.

[0063] FIG. 7 is a diagram schematically showing a configuration example of the power supply and demand adjustment system of the second embodiment. The power supply and demand adjustment system of this embodiment is different from the power supply and demand adjustment system of the first embodiment described above in that the DC power generation system 100 includes a plurality of substations 13 and watt-hour meters 15.

[0064] The supply and demand adjustment device 22 calculates a feedback value using the values of the received power amounts acquired from the plurality of watt-hour meters 15, and calculates an SOC offset value so that the feedback value follows the target received power amount.

[0065] FIG. 8 is a diagram schematically showing a configuration example of the supply and demand adjustment device of the power supply and demand adjustment system shown in FIG. 7. In this embodiment, the supply-demand adjustment device 22 includes a control table selection unit 220, integration units 22A and 22D, a subtraction unit 22B, a gain multiplication unit 22C, a division unit 22E, and an addition unit 22F.

[0066] Values of the received power amounts (ΔWh) of the plurality of substations 13 measured by the plurality of watt-hour meters 15 are input to the addition unit 22F. The addition unit 22F sums up the input values of the plurality of received power amounts (ΔWh) and calculates and outputs the power amount (ΔWh) received by all the substations 13 included in the DC power system 100.

[0067] Values of the received power amounts (ΔWh) of the plurality of substations 13 output from the addition unit 22F are input to the integration unit 22D. The integration unit 22D calculates and outputs a feedback value (kWh) obtained by integrating the input value of the received power amount. The integration unit 22D is synchronized with the integration unit 22A in time, and resets the integration value to zero every preset period. In this embodiment, the integration unit 22D is set to reset the integration value every 30 minutes. Therefore, the output value of the integration unit 22A and the output value of the integration unit 22D are reset simultaneously and become zero.

[0068] The power supply-demand adjustment system of this embodiment is the same as the above-described first embodiment except for the above configuration. Therefore, in the power supply-demand adjustment system of this embodiment, the charge and discharge of the power storage medium 5 are performed by the DC voltage-SOC control using the SOC offset value calculated so that the integrated value (feedback value) of the total received power amount in the plurality of substations 13 follows the target received power amount, and the integrated value of the received power amounts of the plurality of substations 13 will substantially coincide with the target received power amount.

[0069] As described above, according to the power supply-demand adjustment system and the power supply-demand adjustment method of this embodiment, similar to the above-described first embodiment, by adjusting the consumer load by charging and discharging the power storage medium 5 during the supply-demand adjustment execution time period, accurate power supply-demand adjustment can be performed.

[0070] In the power supply and demand adjustment system of this embodiment, since the integrated value of the substation received power amount and the target received power amount are reset simultaneously every predetermined time, it becomes easy to evaluate whether the supply and demand adjustment is accurately performed every predetermined time.

[0071] 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 the 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.

[0072] Although some embodiments of the present invention have been described, these embodiments are presented as examples 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 its equivalent scope.

Explanation of Reference Numerals

[0073] 100... DC power system, 1... DC power line, 2... Return line, 3... Electric vehicle, 4... Power storage device, 5... Power storage medium, 6... Power converter, 7... Power storage control unit, 10... Upper control device, 13... Substation, 15... Power meter, 16... First transformer, 17... Rectifier, 18... Second transformer, 22... Supply and demand adjustment device, 22A... Integration unit, 22B... Subtraction unit, 22C... Gain multiplication unit, 22D... Integration unit, 22E... Division unit, 22F... Addition unit, 220... 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 distribution circuit, comprising: a supply-demand adjustment device that obtains a supply-demand adjustment command including adjustment power and a reference value in a supply-demand adjustment execution time zone, and generates an adjustment amount for adjusting the received power amount from the AC power source so that a feedback value of the received power amount received by the substation from the AC power source follows a target received power amount based on the adjustment power and the reference value; a power storage device including a power storage medium, and during the supply-demand adjustment execution time zone, based on the adjustment amount, the charge state of the power storage medium, and the voltage of the power distribution circuit, charging the power storage medium with the power supplied from the power distribution circuit and supplying the power discharged from the power storage medium to the power distribution circuit. A power supply-demand adjustment system.

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 distribution circuit, comprising: a supply-demand adjustment device that obtains a supply-demand adjustment command including a target received power amount in a supply-demand adjustment execution time zone, and generates an adjustment amount for adjusting the received power amount from the AC power source so that a feedback value of the received power amount received by the substation from the AC power source follows the target received power amount; a power storage device including a power storage medium, and during the supply-demand adjustment execution time zone, based on the adjustment amount, the charge state of the power storage medium, and the voltage of the power distribution circuit, charging the power storage medium with the power supplied from the power distribution circuit and supplying the power discharged from the power storage medium to the power distribution circuit. A power supply-demand adjustment system.

3. The supply-demand adjustment device outputs a control table selection command according to the supply-demand adjustment execution time zone and the value of the adjustment power in the supply-demand adjustment execution time zone. The power storage device includes a plurality of tables including the voltage of the power distribution circuit for charging the power storage medium with respect to the charge state of the power storage medium and the voltage of the power distribution circuit for discharging the power storage medium with respect to the charge state of the power storage medium. Using the table selected according to the control table selection command, according to the charge state of the power storage medium and the voltage of the power distribution circuit, charging the power storage medium with the power supplied from the power distribution circuit and supplying the power discharged from the power storage medium to the power distribution circuit. The power supply-demand adjustment system according to claim 1 or claim 2.

4. The power supply and demand adjustment system according to claim 3, wherein the power storage device adjusts at least one of a lower limit value of a voltage of the power generation circuit that charges the power storage medium with respect to a charge state of the power storage medium and an upper limit value of the power generation circuit that discharges the power storage medium with respect to the charge state of the power storage medium according to the adjustment amount during the power supply and demand adjustment execution time period.

5. The power supply and demand adjustment system according to claim 1 or 2, wherein the power supply and demand adjustment device generates the adjustment amount so that the power storage medium discharges when reducing the power reception amount from the AC power supply during the power supply and demand adjustment execution time period.

6. The power supply and demand adjustment system according to claim 1 or 2, wherein the power supply and demand adjustment device generates the adjustment amount so that the power storage medium charges when increasing the power reception amount from the AC power supply during the power supply and demand adjustment execution time period.

7. The power supply and demand adjustment system according to claim 1 or 2, wherein the adjustment amount is generated using a value obtained by multiplying a gain by a difference between the feedback value and the target power reception amount.

8. A system including a plurality of the substations, The power supply and demand adjustment system according to claim 1 or 2, wherein the power supply and demand adjustment device generates the adjustment amount so that a feedback value obtained by summing power reception amounts received by the plurality of substations from the AC power supply follows the target power reception amount.

9. A power supply and demand adjustment method for adjusting a power reception amount of a substation that supplies DC power obtained by rectifying AC power supplied from an AC power supply to a power generation circuit, obtaining a power supply and demand adjustment command including adjustment power and a reference value during a power supply and demand adjustment execution time period, and generating an adjustment amount for adjusting a load on the AC power supply so that a feedback value of the power reception amount received by the substation from the AC power supply follows a target power reception amount based on the adjustment power and the reference value, A power supply and demand adjustment method for charging the power storage medium with power supplied from the power generation circuit and supplying power discharged from the power storage medium to the power generation circuit based on the adjustment amount, a charge state of the power storage medium, and a voltage of the power generation circuit during the power supply and demand adjustment execution time period.

10. A power supply and demand adjustment method for adjusting a power reception amount of a substation that supplies DC power obtained by rectifying AC power supplied from an AC power supply to a power generation circuit, Obtain a supply-demand adjustment command including the target power reception amount in the implementation time zone of supply-demand adjustment, and generate an adjustment amount for adjusting the load on the AC power supply so that the feedback value of the power reception amount received by the substation from the AC power supply follows the target power reception amount. A power supply-demand adjustment method for charging the power storage medium with the power supplied from the power generation circuit and supplying the power discharged from the power storage medium to the power generation circuit based on the adjustment amount, the charge state of the power storage medium, and the voltage of the power generation circuit in the supply-demand adjustment implementation time zone.

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