Electrical power system
The power system with distributed control in storage battery systems addresses the cost issue of centralized control by independently adjusting output power to stabilize frequency fluctuations, providing primary regulating power efficiently.
Patent Information
- Application Number
- JP2023110116
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-07-04
- Publication Date
- 2025-01-20
AI Technical Summary
Existing frequency adjustment systems require centralized control for primary adjustment power, which is costly due to the need for expensive equipment like SCADA to respond quickly to frequency fluctuations.
A power system with multiple storage battery systems connected to a grid, each equipped with an inverter, frequency measuring device, and a control board that calculates and adjusts output power independently to respond to frequency deviations, providing primary regulating power without centralized control.
The system effectively adjusts power output to stabilize frequency fluctuations at the connection point with the grid, reducing reliance on costly centralized control equipment and enabling rapid response to frequency changes.
Smart Images
Figure 2025008173000001_ABST
Abstract
Description
[Technical field]
[0001] The present disclosure relates to power systems. [Background technology]
[0002] General electricity transmission and distribution companies adjust the balance between electricity demand and supply (supply and demand balance) to ensure a stable supply of electricity. If the supply and demand balance of electricity is disrupted, the frequency of the electricity supplied from the power system will fluctuate, which may affect the operation of production machines in factories and cause large-scale blackouts. Therefore, the supply and demand adjustment market has been partially started as a market where general electricity transmission and distribution companies can procure adjustment power. Adjustment power is electricity for frequency adjustment and supply and demand adjustment. Adjustment power handled in the supply and demand adjustment market is classified into primary adjustment power, secondary adjustment power (1,2), and tertiary adjustment power (1,2) according to requirements such as response time and output duration. Companies that provide adjustment power in the supply and demand adjustment market must meet the requirements stipulated for primary adjustment power, secondary adjustment power, and tertiary adjustment power, respectively. Currently, trading of primary adjustment power in the supply and demand adjustment market is under consideration, but for example, companies that provide primary adjustment power must have the function to detect fluctuating frequency deviations at their own end and respond to reduce the frequency deviations.
[0003] For example, Patent Document 1 discloses a frequency adjustment system that suppresses frequency fluctuations at its own end. The frequency adjustment system described in Patent Document 1 includes a consumer power measuring means, a frequency measuring means, a charging / discharging means, and a charging / discharging control means. The consumer power measuring means is provided at the consumer's power receiving end and measures the power supplied to the consumer. The frequency measuring means measures the frequency of the power system. The charging / discharging means absorbs (charges) power from the power system or releases (discharges) power to the power system according to control from the charging / discharging control means. The charging / discharging control means controls the amount of charging / discharging of the charging / discharging means. The charging / discharging control means is configured to control the amount of charging / discharging using the power measured by the consumer power measuring means and the frequency measured by the frequency measuring means as input signals, and to keep the frequency of the power system within a predetermined range. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] JP 2008-178215 A Summary of the Invention [Problem to be solved by the invention]
[0005] In the frequency regulation system described in Patent Document 1, one frequency measurement means measures the frequency at the receiving end, and the charge / discharge control means controls the charge / discharge of the charge / discharge means based on the frequency. Therefore, in a configuration including multiple charge / discharge means, the multiple charge / discharge means are centrally controlled by one charge / discharge control means. In order to provide primary regulation capacity in the supply and demand adjustment market, it is necessary to respond immediately to frequency fluctuations, for example, within 10 seconds, and to achieve this requirement, the processing speed of the charge / discharge control means is required to be increased. However, in order to realize such a high processing speed, it is possible to use expensive control equipment such as SCADA (Supervisory Control And Data Acquisition) for the charge / discharge control means, but this increases the cost of the system.
[0006] The present disclosure has been devised in consideration of the above circumstances, and its purpose is to provide a power system that can provide primary control power by responding to frequency fluctuations at its own end without relying on centralized control. [Means for solving the problem]
[0007] The power system provided by the present disclosure comprises a plurality of storage battery systems connected to a power grid via connection points and providing primary control capacity to the power grid, and a trading system that trades with a supply and demand adjustment market using the primary control capacity as the trading object, wherein each of the plurality of storage battery systems comprises a storage battery, an inverter that controls the charging and discharging of the storage battery, a frequency meter that measures the frequency of the output voltage of the inverter as an output frequency, a frequency deviation calculation unit that calculates the frequency deviation of the output frequency from a reference frequency, a reference value setting unit that sets an output reference value that is a reference value of the output power of the inverter, an adjustment range calculation unit that calculates an adjustment range for the output reference value using the frequency deviation, a target value calculation unit that calculates an output target value of the inverter by correcting the set output reference value by the adjustment range, and a control unit that controls the output value of the inverter to the output target value.
[0008] In a preferred embodiment of the power system, the reference value setting unit calculates and sets the output reference value.
[0009] In a preferred embodiment of the power system, the system further includes an upper system that communicates with each of the multiple storage battery systems, and the upper system includes an individual reference value calculation unit that calculates an individual reference value for each of the multiple storage battery systems, and a transmission unit that transmits the calculated individual reference value individually to each of the multiple storage battery systems, the individual reference value calculation unit calculates the individual reference value from an overall reference value corresponding to the power value at the connection point, and the reference value setting unit sets the individual reference value received from the upper system as the output reference value.
[0010] In a preferred embodiment of the power system, the power system further includes a load connected to the connection point, and the power value at the connection point is a value obtained by subtracting the power consumption of the load from the sum of the output power of the multiple storage battery systems.
[0011] In a preferred embodiment of the power system, the trading system includes a power meter that measures system power between the connection point and the power grid, and a reporting device that reports the measured output performance of the system power to the balancing market. Effect of the Invention
[0012] In the power system disclosed herein, in each of the multiple storage battery systems, the frequency of the output voltage of the inverter is measured as the output frequency, and the frequency deviation of the output frequency from a reference frequency is calculated. Then, an output target value of the inverter is calculated by correcting a set output reference value by an adjustment width according to the frequency deviation, and the output value of the inverter is controlled to the output target value. Thus, each storage battery system adjusts the output power in response to frequency fluctuations at the connection point with the power grid. As a result, the power system adjusts the output power at the connection point with the power grid to provide primary control reserve to the power grid. Thus, the power system can provide primary control reserve in response to frequency fluctuations at its own end (the connection point with the power grid) without relying on centralized control. [Brief description of the drawings]
[0013] [Figure 1] 1 is a diagram illustrating an example of the overall configuration of a power system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of the configuration of each storage battery system in the power system according to the first embodiment. [Diagram 3] FIG. 11 is a diagram illustrating an example of the overall configuration of a power system according to a second embodiment. [Figure 4] FIG. 11 is a diagram illustrating an example of the overall configuration of a power system according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the power system of the present disclosure will be described below with reference to the drawings. In the following, identical or similar components are designated by the same reference numerals and duplicated descriptions will be omitted.
[0015] FIG. 1 shows an example of the overall configuration of a power system S1 according to a first embodiment. The power system S1 includes a trading system A1 and a plurality of storage battery systems B1. As shown in FIG. 1, in the power system S1, the plurality of storage battery systems B1 are connected to a power grid K via a connection point X1. In the power system S1, all of the plurality of storage battery systems B1 may be operated by one business operator, or the plurality of storage battery systems B1 may be operated by a plurality of business operators. In addition, the trading system A1 may be operated by a business operator that operates at least one of the plurality of storage battery systems B1, or may be operated by an aggregator that bundles the plurality of business operators.
[0016] The power system S1 is connected to the power system K via connection point X2. The power system S1 is capable of outputting power to the power system K via connection point X2. The power system S1 provides primary regulation power to the power system K by adjusting the output power to the power system K in accordance with frequency fluctuations of the output voltage at its own end. The own end of the power system S1 corresponds to connection point X2. In the present disclosure, the responsive frequency fluctuation is a "very short-period" fluctuation, which is a demand fluctuation of about several seconds to several minutes.
[0017] The trading system A1 trades with the supply and demand adjustment market D, with the primary adjustment power provided from the multiple battery storage systems B1 as the trading object. The supply and demand adjustment market D is operated by, for example, a general electricity transmission and distribution company. In the supply and demand adjustment market D, for example, it is divided into blocks of three hours (from 0:00 to 3:00, from 3:00 to 6:00, ..., from 21:00 to 24:00), and the adjustment power (ΔkW) of each three-hour unit is traded as a product block. Note that the above-mentioned three-hour unit time is an example, and can be changed according to the regulations of the supply and demand adjustment market D. When a transaction with the supply and demand adjustment market D is established, the power system S1 provides the primary adjustment power to the power system K in the product block in which the transaction is established. In this embodiment, the power system S1 performs a last-minute measurement type transaction. In this last-minute measurement type transaction, a reference value, etc. in the power system S1 is set using the actual demand (hereinafter, "demand actual demand") immediately before the above-mentioned product block. The reference value is a planned value of the amount of power expected in the case where no adjustment is made to the output power to the power grid K, and is hereinafter referred to as the "overall reference value." The overall reference value may be corrected by a loss rate stipulated in the "Transmission and Supply Terms and Conditions" of the area to which the trading belongs (the area under the jurisdiction of the general electricity transmission and distribution company that operates the supply and demand adjustment market D in which the trading takes place). As shown in FIG. 1, the trading system A1 includes a power meter 11 and a reporting device 12.
[0018] The power meter 11 measures the power (hereinafter referred to as “system power”) at a connection point X2 with the power system K. The connection point X2 is a power receiving point in the power system S1 and corresponds to its own end. The measurement result of the power meter 11 (measured value of the system power) is output to the reporting device 12.
[0019] The reporting device 12 reports the results of the transaction with the supply and demand adjustment market D. The reporting device 12 receives the measured value of the system power from the power meter 11. The reporting device 12 uses the input measured value of the system power to create data on the actual system power output in the product block for which the transaction has been completed. The reporting device 12 then transmits the created data as an actual report to the operator of the supply and demand adjustment market D. In other words, the reporting device 12 reports the measured system power output results to the supply and demand adjustment market D. The format of the created data shall comply with the trading regulations of the supply and demand adjustment market D.
[0020] Each of the storage battery systems B1 is connected to the power system K via a connection point X1. Each of the storage battery systems B1 can output power to the connection point X1. In the example shown in FIG. 1, a transformer is connected between the connection point X1 and the connection point X2, but this transformer may not be required. In this case, the connection point X1 and the connection point X2 are the same. The storage battery systems B1 are, for example, storage battery power conditioners. Each of the storage battery systems B1 calculates a frequency deviation, which will be described later, in a product block in which a transaction has been concluded, and adjusts the output power according to the frequency deviation. Hereinafter, the adjustment of the output power performed by each storage battery system B1 is referred to as "individual output adjustment." Note that each of the storage battery systems B1 controls the output power according to a preset algorithm (existing algorithm) during a time period other than the product block in which a transaction has been concluded.
[0021] FIG. 2 shows an example of the configuration of a plurality of storage battery systems B1. FIG. 2 shows only one of the plurality of storage battery systems B1. As shown in FIG. 2, each of the plurality of storage battery systems B1 includes a storage battery 21, an inverter 22, a frequency meter 23, and a control board 24. The storage battery 21, the inverter 22, the frequency meter 23, and the control board 24 described below are common to each storage battery system B1 unless otherwise specified. Note that the configuration of each storage battery system B1 is not limited to the example shown in FIG. 2.
[0022] The storage battery 21 is, for example, a secondary battery or a capacitor. In FIG. 2, each storage battery system B1 includes one storage battery 21, but may include a plurality of storage batteries 21.
[0023] The storage battery 21 is connected to the inverter 22. The inverter 22 charges and discharges the storage battery 21. The inverter 22 is connected to a connection point X1. The inverter 22 charges the storage battery 21 by supplying power input from the connection point X1 to the storage battery 21. The inverter 22 also discharges the storage battery 21 by outputting power stored in the storage battery 21 to the connection point X1. The charging and discharging performed by the inverter 22 is controlled by a control board 24 (a control unit 245 described below).
[0024] The frequency meter 23 is connected between the inverter 22 and the connection point X1. The frequency meter 23 measures the frequency of the output voltage of the inverter 22 as the output frequency. In the power system S1, the output frequencies measured by the frequency meters 23 of the multiple storage battery systems B1 have the same value. This is because the frequency of the voltage in the power system S1 has the same value as the frequency of the system voltage of the power system K in any of the power lines in the power system S1. The frequency meter 23 outputs the measurement result (measured value of the output frequency) to the control board 24. For example, the frequency meter 23 may be one that is already provided for inverter control in a conventional storage battery power conditioner.
[0025] The control board 24 controls each of the corresponding storage battery system B1. The control board 24 includes at least one or more ICs (Integrated Circuits). As shown in FIG. 2, the control board 24 includes a frequency deviation calculation unit 241, a reference value setting unit 242, an adjustment range calculation unit 243, a target value calculation unit 244, and a control unit 245. The frequency deviation calculation unit 241, the reference value setting unit 242, the adjustment range calculation unit 243, the target value calculation unit 244, and the control unit 245 fulfill the functions of each element by, for example, executing a program stored in at least one or more of the above-mentioned ICs. Unlike this example, at least one of the frequency deviation calculation unit 241, the reference value setting unit 242, the adjustment range calculation unit 243, the target value calculation unit 244, and the control unit 245 may be configured with an analog circuit.
[0026] The frequency deviation calculation unit 241 receives an output frequency from the frequency measurement device 23. The frequency deviation calculation unit 241 calculates the frequency deviation of the output frequency from the reference frequency (for example, output frequency-reference frequency). The reference frequency is a frequency specified in the power system K, and is, for example, 50 Hz in eastern Japan and 60 Hz in western Japan. The reference frequency is stored in advance in the frequency deviation calculation unit 241. As described above, the output frequency measured in each storage battery system B1 has the same value, and therefore the frequency deviations calculated by the frequency deviation calculation units 241 of the multiple storage battery systems B1 have the same value. When the demand exceeds the supply in the power system K, the frequency of the power in the power system K decreases. Therefore, the value of the output frequency input from the frequency measurement device 23 becomes smaller than the reference frequency, and the frequency deviation (output frequency-reference frequency) calculated by the frequency deviation calculation unit 241 becomes a negative value. Conversely, when the demand falls below the supply in the power system K, the frequency of the power in the power system K increases. Therefore, the value of the output frequency input from the frequency measurement device 23 becomes larger than the reference frequency, so that the frequency deviation (output frequency-reference frequency) calculated by the frequency deviation calculation unit 241 becomes a positive value. The frequency deviation calculation unit 241 outputs the calculated frequency deviation to the adjustment width calculation unit 243.
[0027] The reference value setting unit 242 calculates an output reference value and sets the calculated output reference value. The output reference value is a value of output power expected when individual output adjustment according to the frequency deviation is not performed. In this embodiment, a last-minute measurement type transaction is performed with the supply and demand adjustment market D, and the reference value setting unit 242 calculates the output reference value, for example, as follows. That is, the actual output power performance for 5 minutes immediately before the product block in which the transaction is completed is recorded at 1-second intervals, and the average value (or a value calculated from the average value) is calculated as the output reference value. Alternatively, the output target value that was set until immediately before the start of the provision of primary control capacity in the product block in which the transaction is completed (that is, the output target value used in the power control before the function of providing primary control capacity is operated) may be calculated as the output reference value. Note that the calculation method of the output reference value is not limited to these. In this embodiment, the output powers of the storage battery systems B1 are combined at the connection point X1, and the combined output power is output to the power system K via the connection point X2. Therefore, the sum of the output reference values of each storage battery system B1 corresponds to the overall reference value of power system S1. Reference value setting unit 242 outputs the set output reference value to target value calculation unit 244.
[0028] The adjustment width calculation unit 243 calculates an adjustment width for the output reference value by using the frequency deviation. The adjustment width is a value for adjusting the output power amount in the storage battery system B1 in order to reduce the frequency deviation. When the frequency deviation input from the frequency deviation calculation unit 241 is a negative value (i.e., when the demand exceeds the supply in the power system K and the frequency of the power in the power system K drops), the adjustment width is calculated to be, for example, a positive value in order to increase the output power of the storage battery system B1. Conversely, when the frequency deviation input from the frequency deviation calculation unit 241 is a positive value (i.e., when the demand falls below the supply in the power system K and the frequency of the power in the power system K rises), the adjustment width is calculated to be, for example, a negative value in order to decrease the output power of the storage battery system B1. Also, when the frequency deviation input from the frequency deviation calculation unit 241 is 0 (zero) (i.e., when the demand and supply are equal in the power system K), the adjustment width is, for example, 0 (zero) in order to maintain the current output power of the storage battery system B1. In this embodiment, the adjustment range calculation unit 243 calculates the adjustment range by using predetermined setting items in addition to the frequency deviation. The predetermined setting items include the adjustment ratio, the reference frequency, the rated output and the reference frequency of the inverter 22, etc. These setting items may be stored in advance in the adjustment range calculation unit 243, or may be acquired from other components as necessary. The adjustment range calculation unit 243 calculates the adjustment range by performing, for example, the calculation of the following formula (1). In the following formula (1), P ctl_t is the adjustment width, dF is the frequency deviation (preferably an upper bound frequency deviation), Pc is the rated output of the inverter 22, and F ref is the reference frequency, and R is the adjustment ratio. In this way, by taking the above-mentioned setting items into consideration, the adjustment range can be calculated with higher accuracy. Note that the setting items are not limited to the above-mentioned example. Also, the calculation performed by adjustment range calculation unit 243 is not limited to the following formula (1). Adjustment range calculation unit 243 outputs the calculated adjustment range to target value calculation unit 244.
number
[0029] The adjustment range calculated by the adjustment range calculation unit 243 is input to the target value calculation unit 244. The target value calculation unit 244 corrects the set output reference value by the input adjustment range to calculate an output target value. The output target value is a target value of the output power of the inverter 22 (the output power of the corresponding storage battery system B1). In this embodiment, when the adjustment range input from the adjustment range calculation unit 243 is a positive value (i.e., when the demand exceeds the supply in the power system K and the frequency of the power in the power system K drops), the calculated output target value is larger than the output reference value in order to increase the output power of the storage battery system B1. Conversely, when the adjustment range input from the adjustment range calculation unit 243 is a negative value (i.e., when the demand falls below the supply in the power system K and the frequency of the power in the power system K rises), the calculated output target value is smaller than the output reference value in order to decrease the output power of the storage battery system B1. When the adjustment range input from the adjustment range calculation unit 243 is 0 (zero) (i.e., when demand and supply are equal in the power system K), the calculated output target value matches the output reference value in order to maintain the current output power of the storage battery system B1. Note that the target value calculation unit 244 calculates the output target value for time periods other than the product block in which the transaction was concluded, using the above-mentioned predetermined algorithm. The target value calculation unit 244 outputs the calculated output target value to the control unit 245.
[0030] The control unit 245 controls the inverter 22. The control unit 245 controls the output power of the inverter 22 to the input output target value. As described above, when the demand exceeds the supply in the power system K, the input output target value becomes larger than the output reference value, so the control unit 245 increases the output power from the inverter 22 to increase the amount of power supply in the power system K. As a result, the supply in the power system K increases to match the demand, so a decrease in the frequency of the output power in the power system K is suppressed. Conversely, when the demand is lower than the supply in the power system K, the input output target value becomes smaller than the output reference value, so the control unit 245 decreases the output power from the inverter 22 to decrease the amount of power supply in the power system K. As a result, the supply in the power system K decreases to match the demand, so an increase in the frequency of the output power in the power system K is suppressed. In other words, the supply and demand balance is adjusted in the power system K, and the frequency deviation is suppressed. For example, when the input output target value is a positive value, the control unit 245 causes the inverter 22 to discharge the storage battery 21. Conversely, when the input output target value is a negative value, the control unit 245 causes the inverter 22 to charge the storage battery 21.
[0031] In the power system S1 configured as above, the following process is performed in each storage battery system B1. The frequency meter 23 measures the output frequency of the output voltage, and the frequency deviation calculation unit 241 calculates the deviation (frequency deviation) between the output frequency and a reference frequency. The adjustment width calculation unit 243 calculates an adjustment width so that the frequency deviation is reduced with respect to the output reference value set by the reference value setting unit 242, and the target value calculation unit 244 corrects the set output reference value by the adjustment width to calculate the output target value of the inverter 22. Then, the control unit 245 controls the output value (value of output power) of the inverter 22 to the output target value. In this way, in the power system S1, the frequency deviation is calculated in each storage battery system B1, and individual output adjustment according to the frequency deviation is performed. That is, each storage battery system B1 performs individual output adjustment in response to the frequency deviation in a distributed manner. As a result, in the power system S1, the system power at the connection point X2 is adjusted, and the primary adjustment capability is provided to the power grid K. Therefore, the power system S1 can provide primary control reserve in response to frequency fluctuations at its own end (connection point X2 with the power grid K) without relying on centralized control.
[0032] Furthermore, in power system S1, each storage battery system B1 has previously been equipped with a frequency meter 23 for controlling inverter 22. The measurement accuracy of this frequency meter 23 satisfies the requirements (e.g., frequency measurement interval and frequency measurement error) imposed on power system S1 when trading with supply and demand adjustment market D. Therefore, in power system S1, each storage battery system B1 only needs to change the program, etc. in control board 24, which reduces the number of changes from the previous storage battery system.
[0033] Furthermore, in the power system S1, the trading system A1 includes a power meter 11 and a reporting device 12. With this configuration, each storage battery system B1 performs processing related to power control, so the trading system A1 can only perform transactions with the supply and demand adjustment market D and report performance. In other words, in the power system S1, the processing for reporting the system power output performance and the processing for providing primary control reserve (processing for adjusting the power at the connection point X2) can be carried out separately.
[0034] 3 shows an example of the overall configuration of a power system S2 according to the second embodiment. The power system S2 differs from the power system S1 in that it further includes a host system C1.
[0035] The host system C1 is capable of communicating with each of the trading system A1 and the plurality of storage battery systems B1. As shown in FIG.
[0036] The individual reference value calculation unit 31 calculates an individual reference value for each of the multiple storage battery systems B1. The individual reference value corresponds to an output reference value of each storage battery system B1. When the power system S2 is in a immediately preceding measurement type transaction, the individual reference value calculation unit 31 calculates an individual reference value for each storage battery system B1 as follows. First, the individual reference value calculation unit 31 sets an overall reference value based on the value of the system power at the connection point X2 (power value at the connection point X2). The value of the system power at the connection point X2 may be a value (actual measurement value) measured by the power meter 11 of the trading system A1, or may be a value (estimated value) estimated (for example, calculated by summing) from the output power of each storage battery system B1. In the case of an actual measurement value, the individual reference value calculation unit 31 acquires a measurement value of the system power from the trading system A1 (power meter 11). In the case of an estimated value, the individual reference value calculation unit 31 acquires a value of the output power from each storage battery system B1. Then, the set overall reference value is distributed to each storage battery system B1 according to the state of each storage battery system B1, and the distributed value is calculated as each individual reference value. The state of each storage battery system B1 is the rated output of the inverter 22, the maximum capacity of the storage battery 21, and the SoC (State of Charge) of the storage battery 21. For example, the individual reference value of the storage battery system B1 is increased in proportion to the magnitude of the rated output of the inverter 22. Alternatively, the individual reference value calculation unit 31 may calculate the individual reference value of each storage battery system B1 as follows. That is, the individual reference value calculation unit 31 may obtain an actual measurement value of the output power from each storage battery system B1, and calculate the actual measurement value of the output power as the individual reference value of the corresponding storage battery system B1. At this time, the individual reference value may be adjusted according to the state of each storage battery system B1 described above.
[0037] In the power system S2, it is also possible to perform a pre-forecasting type transaction instead of the immediately preceding measurement type transaction. In the pre-forecasting type transaction, a predicted value of the adjustment capacity (primary adjustment capacity) that can be provided is set as an overall reference value for the above-mentioned product block (future product block) to be traded. In the pre-forecasting type, a pre-forecasting type reference value plan based on this set overall reference value is registered in advance in the supply and demand adjustment market D, and trading is performed with the general power transmission and distribution company. Note that the predicted value of the adjustment capacity that can be provided may be calculated based on the past measured value of the system power, or may be calculated based on the actual measured value of the output power of each storage battery system B1. When the power system S2 is such a pre-forecasting type transaction, the individual reference value calculation unit 31 distributes the overall reference value in the product block for which a transaction has been established to each storage battery system B1 according to the state of each storage battery system B1, and calculates the distributed value as the individual reference value for each of the multiple storage battery systems B1.
[0038] The transmitter 32 transmits each individual reference value calculated by the individual reference value calculator 31 to a corresponding one of the multiple storage battery systems B1. The transmission (communication) by the transmitter 32 may be wireless or wired.
[0039] In each storage battery system B1 of this embodiment, the control board 24 (reference value setting unit 242) receives an individual reference value transmitted from the transmission unit 32 of the higher-level system C1. The reference value setting unit 242 then sets the received individual reference value as the output reference value of its own device. In other words, the reference value setting unit 242 of this embodiment does not calculate an output reference value. Other processes (measurement of output frequency, calculation of frequency deviation, calculation of adjustment range, calculation of output target value, etc.) are the same as those of the power system S1.
[0040] In the power system S2 configured as above, similarly to the power system S1, each storage battery system B1 measures the frequency of the output voltage of its own device and calculates a frequency deviation. Then, since individual output adjustment according to the frequency deviation is performed, each storage battery system B1 performs individual output adjustment in response to the frequency deviation in a distributed manner. As a result, in the power system S2 as well, the system power at the connection point X2 is adjusted and a primary control reserve is provided to the power system K. Therefore, similarly to the power system S1, the power system S2 can provide a primary control reserve in response to a frequency fluctuation at its own end (the connection point X2 with the power system K) without relying on a centralized control. Note that in the power system S2, the host system C1 only calculates an output reference value (individual reference value), and individual output adjustment is performed by each storage battery system B1. Therefore, the host system C1 does not need to use expensive control equipment such as SCADA.
[0041] In the power system S2, the output reference value set for each storage battery system B1 is calculated by the higher-level system C1. This configuration can reduce the calculation load of each storage battery system B1. This configuration can also arbitrarily allocate an overall reference value according to the state of each storage battery system B1 described above, so that each storage battery system B1 can adjust its individual reference value. For example, in the power system S2, the individual reference values can be calculated so that some storage battery systems B1 prioritize charging, and the individual reference values can be calculated so that some storage battery systems B1 prioritize discharging. Therefore, the power system S2 can perform more flexible power control.
[0042] 4 shows an example of the overall configuration of a power system S3 according to the third embodiment. The power system S3 differs from the power system S2 in that a load L is further provided.
[0043] A load L is connected to a connection point X1. The load L consumes power supplied from a power grid K or multiple storage battery systems B1. In this embodiment, the value of the system power at the connection point X2 (power value at the connection point X2) is a value obtained by subtracting the power consumption of the load L from the sum of the output powers of the multiple storage battery systems B1.
[0044] In the power system S3 configured as described above, similar to the power system S2 (S1), each storage battery system B1 measures the frequency of its own output voltage and calculates a frequency deviation. Then, each storage battery system B1 performs individual output adjustment in a decentralized manner in response to the frequency deviation. As a result, in the power system S3 as well, the system power at the connection point X2 is adjusted and primary control reserve is provided to the power system K. Therefore, similar to the power system S2 (S1), the power system S3 can provide primary control reserve in response to frequency fluctuations at its own end (the connection point X2 with the power system K) without relying on centralized control.
[0045] Furthermore, the power system S3 includes a load L. With this configuration, the individual reference value calculation unit 31 can reflect the power consumption of the load L in the overall reference value. Therefore, the power system S3 can also provide primary control capacity in the storage battery system B1 included in the power consumer (consumer having the load L).
[0046] The power system according to the present disclosure is not limited to the above-described embodiment. The specific configuration of each part of the power system according to the present disclosure can be freely designed in various ways. [Explanation of symbols]
[0047] S1, S2, S3: power system, A1: trading system, B1: battery system, C1: upper system, D: supply and demand adjustment market, K: power grid, L: load, X1, X2: connection point, 11: power meter, 12: reporting device, 21: battery, 22: inverter, 23: frequency meter, 241: frequency deviation calculation unit, 242: reference value setting unit, 243: adjustment range calculation unit, 244: target value calculation unit, 245: control unit, 31: individual reference value calculation unit, 32: transmission unit
Claims
1. a plurality of storage battery systems connected to a power grid via connection points and supplying primary control power to the power grid; A trading system that trades the primary control capacity with a supply and demand adjustment market; Equipped with Each of the plurality of storage battery systems includes: A storage battery, An inverter that controls charging and discharging of the storage battery; a frequency measuring device that measures a frequency of an output voltage of the inverter as an output frequency; a frequency deviation calculation unit that calculates a frequency deviation of the output frequency from a reference frequency; a reference value setting unit that sets an output reference value that is a reference value of the output power of the inverter; an adjustment range calculation unit that calculates an adjustment range for the output reference value by using the frequency deviation; a target value calculation unit that calculates an output target value of the inverter by correcting the set output reference value by the adjustment width; a control unit that controls an output value of the inverter to the output target value.
2. The power system according to claim 1 , wherein the reference value setting unit calculates and sets the output reference value.
3. A host system that communicates with each of the plurality of storage battery systems, the higher-level system includes an individual reference value calculation unit that calculates an individual reference value for each of the plurality of storage battery systems; and a transmission unit that transmits the calculated individual reference value to each of the plurality of storage battery systems, the individual reference value calculation unit calculates the individual reference value from an overall reference value corresponding to a power value at the connection point; The power system according to claim 1 , wherein the reference value setting unit sets the individual reference value received from the higher level system as the output reference value.
4. a load connected to the connection point; The power system according to claim 3 , wherein the power value at the connection point is a value obtained by subtracting the power consumption of the load from a sum of output powers of the plurality of storage battery systems.
5. The trading system includes: a power meter that measures a system power between the connection point and the power grid; The power system according to claim 1 , further comprising: a reporting device configured to report the measured output performance of the system power to the supply and demand balancing market.
Citation Information
Patent Citations
Frequency regulation system and method
JP2008178215A