Power supply and demand adjustment control system

Abstract

This invention provides a power supply and demand adjustment control system that allows for arbitrary control of the amount of electricity received by the entire electrical load of a substation. [Solution] A power supply and demand adjustment control system for adjusting the amount of power supplied from an AC power source to a substation, comprising: a power storage device 5 connected between a DC / DC converter 6 connected to a feeder circuit and a DC / AC converter 7 connected to an AC power line LAC that supplies AC power from an AC power source to a substation; and a control unit 10 that, during the power supply and demand adjustment period, disconnects the DC / DC converter 6 from the feeder circuit and controls the DC / AC converter 7 to output active power from the power storage device 5 to the AC power line LAC.

Description

Technical Field

[0001] Embodiments of the present invention relate to a power supply and demand adjustment control system.

Background Art

[0002] In order to supply power stably, it is essential to secure supply and demand adjustment power for performing frequency control and supply and demand balance adjustment in the power supply area. The supply and demand adjustment power is the power supply force for matching supply (power generation) with the power demand (consumption) that changes every moment. In recent years, a supply and demand adjustment market that enables the trading of supply and demand adjustment power has been established. Various methods for providing supply and demand adjustment power according to the supply and demand plan of power required in the supply and demand adjustment market have been proposed.

[0003] With the spread of distributed power sources such as solar power generation and wind power generation, VPP (Virtual Power Plant) has attracted attention as one method for providing supply and demand adjustment power. VPP integrates and controls distributed power sources including renewable energy facilities and storage batteries, and provides supply and demand adjustment power by systematically adjusting the stored energy. The application fields of VPP are diverse, and its application has also been proposed in the field of electric railways.

[0004] Here, as one method of supplying power to railway vehicles in an electric railway, a DC third-rail power supply system is known. In the DC third-rail power supply system, in order to counter regeneration failure or overhead wire voltage drop, a substation facility for an electric railway including a storage battery or a storage element (hereinafter simply referred to as "storage battery") may be connected. By charging and discharging the storage battery, improvement of the regeneration rate and stabilization of the overhead wire voltage can be achieved.

[0005] Furthermore, regarding the adjustment of power supply and demand in the electric railway sector, attempts have been reported to reduce peak power by supplying power from secondary batteries connected to the feeder lines. The secondary batteries are connected directly to the overhead lines, or to the overhead lines via converters such as choppers, and charge and discharge in response to decreases or increases in the overhead line voltage. Attempts have also been reported to connect storage batteries to the feeder lines via converters and discharge the storage batteries by increasing the output voltage. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2023-023565 [Overview of the project] [Problems that the invention aims to solve]

[0007] The energy storage device could only discharge energy to the loads within the DC power supply system surrounding the device, and could not discharge energy exceeding the demand of the loads within the power supply system. When attempting to control the amount of power received per unit time for the entire electrical load of a substation, including train loads, station loads, and ancillary loads such as signal loads, to a target value, it was difficult to appropriately control the amount of power received because arbitrary discharge from the battery was not possible.

[0008] Embodiments of the present invention have been made in view of the above circumstances, and aim to provide a power supply and demand adjustment control system that can arbitrarily control the amount of power received by the entire electrical load of a substation. [Means for solving the problem]

[0009] The power supply and demand adjustment control system according to this embodiment is a system for adjusting the amount of power supplied from an AC power source to a substation, and comprises a DC / DC converter connected to a feeder circuit, a power storage device connected between a DC / AC converter connected to an AC power line that supplies AC power from the AC power source to the substation, and a control unit that controls the DC / AC converter to charge and discharge the power storage device during the power supply and demand adjustment period to output active power to the AC power line. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic diagram showing one example configuration of the power supply and demand adjustment control system of the first embodiment. [Figure 2A] Figure 2A is a schematic diagram showing one example configuration of the energy storage device shown in Figure 1. [Figure 2B] Figure 2B is a schematic diagram showing one example configuration of the energy storage device shown in Figure 1. [Figure 3] Figure 3 is a schematic diagram showing one example configuration of the power supply and demand adjustment control system of the second embodiment. [Figure 4] Figure 4 is a schematic diagram showing one example configuration of the power supply and demand adjustment control system of the third embodiment. [Modes for carrying out the invention]

[0011] The power supply and demand adjustment control system of this embodiment will be described below with reference to the drawings. Figure 1 is a schematic diagram showing one example configuration of the power supply and demand adjustment control system of the first embodiment. The power supply and demand adjustment control system 100 of this embodiment may provide adjustment capabilities (tertiary adjustment capabilities (1)) to address the difference between demand and supply caused by demand forecast errors and renewable energy output forecast errors that occur after the gate closes, as well as power outages due to power supply problems, etc.

[0012] The power supply and demand adjustment control system 100 of this embodiment is, for example, installed in a DC power supply system that supplies power to a vehicle (hereinafter referred to as "electric vehicle") 3 such as an electric railway or monorail. The DC power supply system receives three-phase AC power from an AC power system AC and supplies DC power to the electric vehicle (train load) 3 via a DC power supply line 1 and a return line 2. The return line 2 is, for example, the rail on which the electric vehicle 3 runs. The DC power supply system is grounded by the return line 2. The electric vehicle 3 runs by receiving DC power from a DC power supply line 1 such as an overhead line or a third rail.

[0013] The DC power supply system of this embodiment includes a power supply and demand adjustment control system 100, a substation, and a higher-level control device 15. The substation includes a transformer 11 and a diode rectifier 12. The first transformer 11 converts the voltage of the three-phase AC power received from the AC power system and supplies it to the diode rectifier 12.

[0014] The diode rectifier 12 outputs DC power, which is obtained by rectifying the AC power output from the first transformer 11, to the power supply circuit (including the DC power supply line 1 and the return line 2). Furthermore, the AC power supplied from the AC power system (AC power) to the substation is supplied not only to the power supply circuit (train load) via the first transformer 11 and diode rectifier 12, but also to electrical loads including station loads (first electrical load including station lighting, air conditioning, elevators, etc.) and equipment necessary for the operation of electric trains 3, such as signals (second electrical load including incidental loads).

[0015] The higher-level control unit 15 is, for example, a computing device (server device) comprising a processor and a memory storing a program executed by the processor, and can realize various functions described below by software or by a combination of software and hardware.

[0016] The upper control device 15 obtains the available adjustment amount in the future (for example, the next day after the bidding date of the adjustment power) from the supply-demand adjustment device 8 described later (the amount that can reduce the load on the consumer side (downward DR amount), the amount that can increase the load on the consumer side (upward DR amount)), and bids the available adjustment amount 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 15 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 15 prior to the implementation time of supply-demand adjustment. The upper supply-demand adjustment command may include information on the time requesting the implementation of supply-demand adjustment and the adjustment amount of supply-demand energy. The upper control device 15 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 as a reference value (the value of the received power of the substation assumed in the case where there is no supply-demand adjustment command), and the supply-demand adjustment implementation time zone. The upper control device 15 supplies the generated supply-demand adjustment command to the supply-demand adjustment device 8.

[0017] In this embodiment, the upper control device 15 calculates the adjustment power value by setting the downward DR amount as positive and the upward DR amount as negative, for example. The adjustment power value may be set, for example, as the value of the amount of power to be supply-demand adjusted over the entire time zone during which supply-demand adjustment is implemented, or may be time-series data of the adjustment amount (adjustment power) of the received power within the time zone during which supply-demand adjustment is implemented.

[0018] 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 referring 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, or on a per-consumer basis, the average value of the actual demand amount in the 6 intervals in 30-minute units before the supply-demand adjustment implementation time zone on the day of supply-demand adjustment implementation (for example, from 4 hours before to 1 hour before) may be set as the baseline.

[0019] The power supply and demand adjustment control system 100 includes a power storage device 4, a supply and demand adjustment device 8, and a power meter 9. The power meter 9 measures the received power value of an electrical load including a train load, a station load, and an incidental load such as a signal load that receives power from the AC power supply system AC. The measured value of the power meter 9 is supplied to the supply and demand adjustment device 8.

[0020] The supply and demand adjustment device 8 is configured to be communicable with the upper control device 15 and the power storage device 4. Also, the supply and demand adjustment device 8 can acquire the measured value of the power meter 9. The supply and demand adjustment device 8 is, for example, an arithmetic device (server device) including a processor and a memory that stores a program executed by the processor, and can realize various functions described below by software or a combination of software and hardware.

[0021] The supply and demand adjustment device 8 receives a supply and demand adjustment command from the upper control device 15, and in the supply and demand adjustment time zone, outputs a command related to charging and discharging (including the charging power amount and the discharging power amount) to the control unit 10 of the power storage device 4 so that the total power consumption of the electrical load of the substation matches the target received power amount.

[0022] When the supply and demand adjustment device 8 receives an adjustment power value, a baseline, and a supply and demand adjustment execution time from the upper control device 15, and acquires the measured value of the received power of the substation from the power meter 9, it can calculate the actual received power amount in a predetermined time by integrating (integrating) the measured values for a predetermined time. The supply and demand adjustment device 8 calculates the difference between the target received power amount based on the adjustment power value and the baseline and the feedback value using the actual received power amount as a feedback value, and generates the charging power amount and the discharging power amount for supply and demand adjustment (hereinafter referred to as the charge and discharge power amount) so that the difference becomes zero (so that the feedback value follows the target received power amount), and transmits it to the control unit 10 of the power storage device 4.

[0023] In this configuration, the supply and demand adjustment device 8 calculates the target power received (kW) based on the adjusted power value and baseline from the higher-level control device 15. However, it is also possible to configure the system so that the higher-level control device 15 transmits the target power received (kW) (or target power received amount (kWh)) during the supply and demand adjustment period as a supply and demand adjustment command. The supply and demand adjustment device 8 may also calculate the target power received (kW) from the target power received amount (kWh).

[0024] Furthermore, the supply and demand adjustment device 8 may calculate a predicted value of the amount of power received by the substation (the entire electrical load), generate the amount of power to charge and discharge for supply and demand adjustment so that the predicted value of the amount of power received follows the target amount of power received, and transmit it to the control unit 10 of the energy storage device 4. The predicted value of the amount of power received by the substation may be calculated, for example, based on a baseline, or for example, based on data accumulated from past actual values ​​of power received.

[0025] The supply and demand adjustment device 8 may charge and discharge the energy storage device 5 in advance of the time period in which supply and demand adjustment is performed, so that supply and demand adjustment can be performed. The supply and demand adjustment device 8 may forcibly charge the energy storage device 5 before a downward demand response (DR) is performed to reduce the load on the consumer side through supply and demand adjustment, so that the energy storage device 5 can discharge the amount of electricity produced by the supply and demand adjustment during the time period in which supply and demand adjustment is performed. Alternatively, the supply and demand adjustment device 8 may forcibly discharge the energy storage device 5 before an upward demand response (DR) is performed to increase the load on the consumer side through supply and demand adjustment, so that the energy storage device 5 can charge the amount of electricity produced by the supply and demand adjustment during the time period in which supply and demand adjustment is performed.

[0026] Furthermore, the supply and demand adjustment device 8 obtains the rated capacity and state of health (SOH) of the energy storage device 5 from the energy storage device 4, and can calculate the amount of available adjustments in the future (for example, the day after the bidding date for available adjustments), taking system efficiency into account, based on the effective battery capacity of the energy storage device 5 (rated capacity of the energy storage device 5 × SOH × charge / discharge margin). The supply and demand adjustment device 8 transmits the calculated amount of available adjustments to the higher-level control device 15 by a predetermined deadline.

[0027] The energy storage device 4 comprises an energy storage device 5, a DC / DC converter 6, a DC / AC converter 7, a control unit 10, a second transformer 13, and a contactor 14. The energy storage device 5 may include energy storage elements capable of storing electrical energy, such as secondary batteries, fuel cells, capacitors, and flywheels.

[0028] Figures 2A and 2B schematically show one example configuration of the energy storage device shown in Figure 1. In this embodiment, the energy storage device 5 includes at least one energy storage module BT equipped with a battery pack containing a plurality of rechargeable battery cells such as lithium-ion batteries, nickel-metal hydride batteries, or lead-acid batteries, and a cell monitoring unit (CMU). The battery pack (not shown) includes, for example, 24 battery cells connected in 2 parallel and 12 series of 20Ah battery cells.

[0029] A CMU (not shown) is configured to communicate with a control unit 10, which will be described later. The CMU periodically measures the voltage and temperature of each battery cell (or battery pack) and the charging and discharging currents (charge / discharge currents) of the energy storage device 5, and notifies the control unit 10 of the measurement results. The CMU may also use the voltage and temperature of each battery cell (or battery pack) and the charge / discharge currents of the energy storage device 5 to calculate the charge state (SOC) and state of health (SOH) of the energy storage device 5, and notify the control unit 10 of the calculation results. In this case, the CMU can calculate the SOC and SOH using a general calculation method.

[0030] Furthermore, the energy storage device 5 may include a DC / DC converter 5A, as shown in Figure 2B. The DC / DC converter 5A is controlled by the control unit 10 to charge and discharge the battery pack BT.

[0031] The DC / DC converter 6 is electrically connected between the energy storage device 5 and the power supply circuit. The DC / DC converter 6 includes, for example, a DC / DC converter. The DC / DC converter 6 detects the voltage of the DC power supply line 1 and, according to the values ​​of the charging start voltage and discharge start voltage supplied from the control unit 10, converts the DC power discharged from the energy storage device 5 into DC power of a predetermined voltage and discharges it to the power supply circuit, and also converts the regenerative power supplied from the power supply circuit into DC power of a predetermined voltage and charges the energy storage device 5. The charging start voltage is the voltage of the power supply circuit (DC power supply line 1) when the energy storage device 5 is being charged. The discharge start voltage is the voltage of the power supply circuit (DC power supply line 1) when the energy storage device 5 is being discharged. The charging start voltage is, for example, the lower limit of the voltage of the power supply circuit (DC power supply line 1) when the energy storage device 5 is being charged. The discharge initiation voltage is, for example, the upper limit of the voltage in the feeder circuit (DC feeder line 1) when the energy storage device 5 is discharged.

[0032] However, the DC / DC converter 6 is not limited to this example; any converter may be used depending on the type of energy storage device 5 and the power circuit. The DC / DC converter 6 may also be equipped with a current limiter to control the limit value of the charge and discharge current.

[0033] The contactor 14 switches the electrical connection state between the DC / DC converter 6 and the DC feeder line 1. The contactor 14 is, for example, an electromagnetic contactor, and its switching operation between connection and disconnection is controlled by the control unit 10.

[0034] The DC / AC converter 7 is electrically connected between the energy storage device 5 and the AC power line LAC that supplies power from the AC power system AC to the first transformer 11. The DC / AC converter 7 includes, for example, a DC / AC inverter. The DC / AC converter 7 can be operated to output active power (three-phase AC power) to the AC power line LAC via the second transformer 13 in response to a control command from the control unit 10. The DC / AC converter 7 can also supply power acquired from the AC power line LAC to the energy storage device 5 via the second transformer 13 in response to a control command from the control unit 10.

[0035] In other words, the active power supplied to the AC power line LCA can take on positive or negative values. In this specification, when the active power is positive, AC power is supplied to the AC power line LCA by the power discharged from the energy storage device 4, and when the active power is negative, the energy storage device 4 is charged by the AC power supplied from the AC power line LCA.

[0036] The second transformer 13 transforms the AC power output from the DC / AC converter 7 and outputs it to the AC power line LCA, and also transforms the AC power supplied from the AC power line LCA and outputs it to the DC / AC converter 7.

[0037] The control unit 10 includes, for example, at least one processor and a memory in which a program executed by the processor is stored, and includes an arithmetic circuit configured to realize various functions described below by software or by a combination of software and hardware. The control unit 10 is configured to communicate with the supply and demand adjustment device 8 and can control the DC / DC converter 6 to charge and discharge the energy storage device 5 based on the voltage of the DC feeder line 1 and the state of charge (SOC) of the energy storage device 5.

[0038] Furthermore, the control unit 10 is configured to communicate with the energy storage device 5. The control unit 10 acquires information about the energy storage device 5 from the energy storage device 5, such as the voltage and temperature of the battery cells (or battery pack) measured by the energy storage device 5, the value of the charge / discharge current of the energy storage device 5, the state of charge (SOC), and the state of degradation (SOH). The control unit 10 may also calculate the state of charge (SOC) and the state of degradation (SOH) of the energy storage device 5 using the values ​​such as voltage, charge / discharge current, and temperature acquired from the energy storage device 5.

[0039] Furthermore, the control unit 10 is configured to communicate with the DC / DC converter 6 and transmits control commands to the DC / DC converter 6. The control commands transmitted from the control unit 10 to the DC / DC converter 6 may include, for example, the voltage of the DC feeder line 1 to start charging the energy storage device 5 (charging start voltage), the voltage of the DC feeder line 1 to start discharging the energy storage device 5 (discharge start voltage), the allowable current value that can flow through the energy storage device 5, and the maximum discharge power value and maximum charge power value that can be output from the DC / DC converter 6 to the feeder circuit.

[0040] The control unit 10 may adjust the discharge start voltage and the charge start voltage according to the state of charge (SOC) of the energy storage device 5. For example, if the SOC of the energy storage device 5 decreases, the discharge start voltage and the charge start voltage will decrease. For example, if the SOC of the energy storage device 5 increases, the discharge start voltage and the charge start voltage will increase. This charge and discharge control of the energy storage device 5, which adjusts the discharge start voltage and the charge start voltage, is called feed voltage-SOC control.

[0041] The control unit 10 may perform the feeder voltage-SOC control according to a pre-set table of discharge start voltage / charge start voltage-SOC. In this case, the control unit 10 may store multiple tables corresponding to multiple patterns of feeder voltage-SOC, select a table based on a control table selection command from the supply and demand adjustment device 8, and use the selected table to supply the charge start voltage and discharge start voltage for the SOC of the energy storage device 5 to the DC / DC converter 6 to perform feeder voltage-SOC control. In this embodiment, the control unit 10 includes, for example, a discharge start voltage / charge start voltage-SOC table that includes at least a normal grid connection table, a forced charge table, and a forced discharge table.

[0042] Furthermore, the control unit 10 is configured to communicate with the DC / AC converter 7 and transmits control commands to the DC / AC converter 7. The control unit 10 can adjust the active power supplied to the AC power line LAC via the second transformer 13 during the supply and demand adjustment period, according to the amount of charge and discharge power notified by the supply and demand adjustment device 8.

[0043] Next, an example of the operation of the power supply and demand adjustment control system 100 when performing supply and demand adjustment control will be described. When the time for the supply and demand adjustment command to begin, the supply and demand adjustment device 8 calculates the amount of power to be charged and discharged for supply and demand adjustment and transmits it to the control unit 10 of the energy storage device 4.

[0044] When the supply and demand adjustment start time arrives, the supply and demand adjustment device 8, via the control unit 10, opens the contactor 14, electrically disconnecting the feeder circuit from the DC / DC converter 6. Alternatively, the control unit 10 may stop the DC / DC converter 6 without opening the contactor 14 at the supply and demand adjustment start time.

[0045] Next, the control unit 10 controls the DC / AC converter 7 according to the amount of charge and discharge power supplied from the supply and demand adjustment device 8, causing the energy storage device 5 to charge and discharge. Specifically, the control unit 10 controls the DC / AC converter 7 based on the amount of charge and discharge power from the supply and demand adjustment device 8, causing the energy storage device 5 to output active power equivalent to the amount of charge and discharge power to the AC power line LAC. As a result, the amount of power received supplied from the AC power system AC to the AC power line LAC becomes equal to the target amount of power received.

[0046] The active power output from the DC / AC converter 7 to the AC power line LAC can be positive or negative. When the active power is positive, the energy storage device 5 discharges, supplying active power to the AC power line LAC. When the active power is negative, the energy storage device 5 is charged by the active power supplied from the AC power line LAC to the energy storage device 4.

[0047] In this embodiment, the AC power line LAC is configured to allow power to be exchanged between the energy storage device 4 and electrical loads such as station loads and ancillary loads. Therefore, the supply and demand adjustment device 8 can adjust the power supplied to the entire electrical load of the substation by charging and discharging the energy storage device 5, regardless of the load conditions of the DC power supply circuit.

[0048] When the supply and demand adjustment time is reached, the supply and demand adjustment device 8 finishes calculating the amount of power to be charged and discharged for supply and demand adjustment, and the control unit 10 closes the contactor 14, electrically connecting the feeder circuit and the DC / DC converter 6.

[0049] Outside of the supply and demand adjustment period, the control unit 10 selects a table of discharge start voltage / charge start voltage-SOC based on a control table selection command from the supply and demand adjustment device 8, for example, and controls the operation of the DC / DC converter 6 according to the selected table. That is, the DC / DC converter 6 detects the voltage of the DC feeder line 1 and, according to the values ​​of the charge start voltage and discharge start voltage supplied from the control unit 10, converts the DC power discharged from the energy storage device 5 into DC power of a predetermined voltage and discharges it to the feeder circuit, and converts the regenerative power supplied from the feeder circuit into DC power of a predetermined voltage and charges the energy storage device 5.

[0050] As described above, according to the power supply and demand adjustment control system 100 of this embodiment, when controlling the amount of power received per unit time for the entire electrical load of a substation, including train loads, station loads, and ancillary loads such as signal loads, to a target value, it is possible to adjust the power received by the substation (entire electrical load) by charging and discharging the energy storage device 5. In other words, according to this embodiment, it is possible to provide a power supply and demand adjustment control system that can arbitrarily control the amount of power received by the substation (entire electrical load).

[0051] Next, a modified example of the power supply and demand adjustment control system of the first embodiment will be described in detail with reference to the drawings. Figure 3 is a schematic diagram showing a modified example of the power supply and demand adjustment control system of the first embodiment. The power supply and demand adjustment control system of this embodiment differs from the first embodiment described above in that the station load is electrically connected to the power supply path between the second transformer 13 and the DC / AC converter 7.

[0052] Even when the station load and the energy storage device 4 are connected in this manner, the same effects as those of the first embodiment described above can be obtained. That is, according to a modified version of the first embodiment, it is possible to provide a power supply and demand adjustment control system that can arbitrarily control the amount of power received by the entire electrical load of the substation.

[0053] Furthermore, according to the configuration shown in Figure 3, the active power from the DC / AC converter 7 to the station load is supplied without going through the second transformer 13, thus eliminating energy loss in the transformer and improving the energy supply efficiency from the energy storage device 4 to the station load.

[0054] Next, the power supply and demand adjustment control system of the second embodiment will be described in detail with reference to the drawings. Furthermore, the power supply and demand adjustment control system 100 of this embodiment may, for example, provide adjustment capacity (tertiary adjustment capacity (2)) that corresponds to prediction errors of renewable energy utilizing the FIT special exemption system (1) and the FIT special exemption system (3) in the supply and demand adjustment market.

[0055] The power supply and demand adjustment control system 100 of this embodiment differs from the first embodiment described above in that it does not include a power meter 9, and the DC / AC converter 7 detects the voltage at the AC grid connection point.

[0056] In this embodiment, the supply and demand adjustment device 8 may have prior arrangements (agreements) with the higher-level control device 15 to provide available adjustment power, etc., and to provide power adjustment power during the supply and demand adjustment period. The supply and demand adjustment device 8 notifies the control unit 10 of the energy storage device 4 of the supply and demand adjustment period in accordance with the arrangement with the higher-level control device 15.

[0057] During the supply and demand adjustment period notified by the supply and demand adjustment device 8, the control unit 10 opens the contactor 14 to electrically disconnect the DC / DC converter 6 from the electrical circuit. Also, during the supply and demand adjustment period, the control unit 10 monitors the frequency of the AC power supplied from the AC power system by the DC / AC converter 7 and charges and discharges the energy storage device 5 so that the frequency is within a predetermined value (within a predetermined range).

[0058] Furthermore, the control unit 10 may acquire the amount of charge and discharge power (or time-series data of charge current and discharge current) from the energy storage device 5 during the supply and demand adjustment period, and notify the higher-level control unit 15 of the results of the supply and demand adjustment (for example, the amount of charge and discharge power) after the supply and demand adjustment period has ended.

[0059] The DC / AC converter 7 has a function to detect the frequency of the AC power voltage at the AC side connection terminal and controls the active power supplied to the substation by the AC power line LAC during the supply and demand adjustment period. During the supply and demand adjustment period, if the DC / AC converter 7 detects that the detected frequency of the AC voltage has fallen below a predetermined threshold, it discharges the energy storage device 5 and supplies active power to the AC power line LAC. Also, during the supply and demand adjustment period, if the detected frequency of the AC voltage rises above a predetermined threshold, the DC / AC converter 7 charges the energy storage device 5 with AC power supplied from the AC power line LAC.

[0060] The power supply and demand adjustment control system 100 of this embodiment has the same configuration as the first embodiment described above, except for the above-mentioned components. As described above, the power supply and demand adjustment control system 100 of this embodiment makes it possible to adjust the power supplied to the entire electrical load of the substation by charging and discharging the energy storage device 5, regardless of the load conditions of the DC power supply circuit. In other words, this embodiment provides a power supply and demand adjustment control system that can arbitrarily control the amount of power received by the entire electrical load of the substation.

[0061] In the second embodiment, as with the modification of the first embodiment described above, the station load may also be electrically connected to the power supply path between the second transformer 13 and the DC / AC converter 7. Even in this case, the same effects as in the second embodiment described above can be obtained.

[0062] The program according to this embodiment may be transferred while stored on an electronic device, or it may be transferred while not stored on an electronic device. In the latter case, the program may be transferred via a network, or it may be transferred while stored on a storage medium. The storage medium is a non-temporary tangible medium. The storage medium is a computer-readable medium. The storage medium can be any medium that is capable of storing a program and is readable by a computer, such as a CD-ROM or memory card, and its form is not limited.

[0063] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0064] 1... DC feeder line, 2... return line, 3... electric vehicle, 4... energy storage device, 5... energy storage device, BT... energy storage module, 5A... DC / DC converter, 6... DC / DC converter, 7... DC / AC converter, 8... supply and demand adjustment device, 9... electricity meter, 10... control unit, 11... first transformer, 12... diode rectifier, 13... second transformer, 14... contactor, 15... higher-level control device, 100... power supply and demand adjustment control system, LAC... AC power line

Claims

1. A system that adjusts the amount of electricity supplied from an AC power source to a substation, A power storage device is connected between a DC / DC converter connected to a power supply circuit and a DC / AC converter connected to an AC power line that supplies AC power from the AC power source to the substation, A power supply and demand adjustment control system comprising: a control unit that controls the DC / AC converter to charge and discharge the energy storage device during the power supply and demand adjustment period to output active power to the AC power line.

2. A power meter for measuring the amount of electricity supplied from the AC power source to the substation, The supply and demand adjustment device further includes a supply and demand adjustment command that acquires the adjustment power and reference value during the supply and demand adjustment period, calculates the value of the charge and discharge power amount corresponding to the difference between the measured value of the electricity meter and the target power received based on the adjustment power and the reference value, and supplies it to the control unit, The power supply and demand adjustment control system according to claim 1, wherein the control unit controls the DC / AC converter during the supply and demand adjustment period to charge and discharge the energy storage device according to the value of the charge and discharge power supplied from the supply and demand adjustment device and output active power to the AC power line.

3. The DC / AC converter, during the supply and demand adjustment period, detects the frequency of the AC voltage supplied from the AC power source to the substation using the voltage at the AC-side connection terminal, and charges and discharges the energy storage device according to the frequency. The power supply and demand adjustment control system according to claim 1, wherein the control unit acquires the amount of power charged and the amount of power discharged from the energy storage device and outputs them to the outside.

4. The power supply and demand adjustment control system according to claim 1, wherein the control unit electrically disconnects the DC / DC converter and the power supply circuit during the power supply and demand adjustment period.

5. The power supply and demand adjustment control system according to any one of claims 1 to 4, wherein the substation comprises a transformer electrically connected to the AC power line and transforming AC power supplied from the AC power source, a rectifier that rectifies the AC power transformed by the transformer and outputs it to the power supply circuit, and an electrical load electrically connected to the AC power line.

6. The DC / AC converter is electrically connected to the AC power line via a second transformer. The power supply and demand adjustment control system according to any one of claims 1 to 4, wherein the substation comprises a transformer electrically connected to the AC power line and transforming AC power supplied from the AC power source, a rectifier that rectifies the AC power transformed by the transformer and outputs it to the power supply circuit, a first electrical load connected between the DC / AC converter and the second transformer, and a second electrical load electrically connected to the AC power line.

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