A method, device and electronic equipment for coordinated control of frequency modulation and AGC

Abstract

The application discloses a kind of primary frequency modulation and AGC coordination control method, device and electronic equipment, wherein method includes: judging whether to enter primary frequency modulation control;If not enter primary frequency modulation control, then set the SOC upper and lower limits of energy storage power station put into operation are first limit and second limit respectively, and reserve preset proportion capacity does not participate in output, then AGC instruction is distributed to wind power station, photoelectric station and energy storage power station execution;If enter primary frequency modulation control, then set the SOC upper and lower limits of energy storage power station put into operation are third limit and fourth limit respectively, and release all capacity to participate in output;Primary frequency modulation instruction increment is calculated, and after primary frequency modulation instruction increment and the AGC instruction obtained are superposed, it is distributed to wind power station, photoelectric station and energy storage power station execution;Wherein third limit is higher than first limit, and fourth limit is lower than second limit.The technical scheme provided by the application realizes a kind of primary frequency modulation and AGC coordination control scheme considering energy storage life and frequency modulation target.

Description

Technical Field

[0001] This invention relates to the field of power systems, and more specifically to a method, apparatus, and electronic device for coordinated control of primary frequency regulation and AGC. Background Technology

[0002] Currently, the strategy for coordinated control between primary frequency regulation, secondary frequency regulation (Automatic Generation Control, AGC), and the primary and secondary frequency regulation in wind, solar, and energy storage power stations is a hot research topic. Patent document CN114696342A discloses a fast frequency regulation control method for wind, solar, and energy storage power stations that considers AGC coordination. This method discloses the timing for primary frequency regulation to join and leave AGC, and how primary frequency regulation commands and AGC commands are superimposed according to their control directions.

[0003] However, existing technologies rarely consider factors that affect energy storage lifespan, thus the frequent command changes generated during the coordinated control of primary frequency regulation and AGC affect the energy storage lifespan. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a method, apparatus and electronic device for coordinated control of primary frequency regulation and AGC, realizing a coordinated control scheme for primary frequency regulation and AGC that takes into account both energy storage life and frequency regulation target.

[0005] According to a first aspect, embodiments of the present invention provide a coordinated control method for primary frequency regulation and AGC, the method comprising: determining whether primary frequency regulation control is initiated; if primary frequency regulation control is not initiated, setting the upper and lower limits of the State of Charge (SOC) of the energy storage power station to be put into operation as a first limit and a second limit, respectively, and reserving a preset proportional capacity not to participate in power output; acquiring an AGC instruction and allocating the AGC instruction to a wind power station, a solar power station, and the energy storage power station for execution; if primary frequency regulation control is initiated, setting the upper and lower limits of the SOC of the energy storage power station to be put into operation as a third limit and a fourth limit, respectively, and releasing all capacity to participate in power output; calculating the primary frequency regulation instruction increment, and superimposing the primary frequency regulation instruction increment with the acquired AGC instruction, and allocating it to the wind power station, the solar power station, and the energy storage power station for execution; wherein the third limit is higher than the first limit, and the fourth limit is lower than the second limit.

[0006] Optionally, the method further includes: upon entering primary frequency regulation control, determining whether to exit primary frequency regulation control; if exiting primary frequency regulation control, obtaining the AGC commands allocated to the wind power station, solar power station, and energy storage power station in the previous control cycle; calculating the command difference between the AGC commands allocated to the wind power station, solar power station, and energy storage power station in the current control cycle and the AGC commands allocated in the previous control cycle; if any command difference is less than a preset command change dead zone, correcting the AGC command allocated to the corresponding power station in the current control cycle to the AGC command allocated in the previous control cycle; if any command difference is greater than a preset active power command change step size, correcting the AGC command allocated to the corresponding power station in the current control cycle to the sum of the AGC command allocated in the previous control cycle in the control direction and the preset active power command change step size.

[0007] Optionally, the step of assigning the AGC command to the wind power station, the solar power station, and the energy storage station for execution includes: obtaining the control modes of the wind power station, the solar power station, and the energy storage station respectively, and determining whether the AGC command is valid. The control modes include the station centralized control mode, the grid direct dispatch mode, and the exit control mode. If the AGC command is valid, the difference between the AGC command and the actual active power generated by the corresponding power station under the grid direct dispatch mode is calculated to obtain the station execution command. The station execution command is then assigned to the corresponding power station under the station centralized control mode for execution.

[0008] Optionally, determining whether the AGC command is valid includes: determining whether the active power data of the grid-connected point stops refreshing within a preset time interval; if refreshing stops, then the AGC command is determined to be invalid; if refreshing does not stop, then determining whether the actual active power generated by the grid-connected point is greater than a preset multiple of the total capacity of the entire power station or less than 0; if the actual active power generated by the grid-connected point is greater than a preset multiple of the total capacity of the entire power station or less than 0, then the AGC command is determined to be invalid.

[0009] Optionally, if the wind power station and energy storage power station are in the site centralized control mode, and the photovoltaic power station is in the grid direct dispatch mode, then the step of allocating the site execution command to the corresponding power station in the site centralized control mode includes: calculating the command deviation between the current active power generated at the grid connection point and the AGC command; if the command deviation is greater than the preset site allowable deviation dead zone, then the site execution command is allocated to the wind power station according to the following formula.

[0010]

[0011] And allocate site execution instructions to the energy storage power station according to the following formula.

[0012]

[0013] In the formula, This indicates the portion of the wind power plant that is allocated from the site according to the instructions. This indicates that the station is executing instructions, and This refers to the AGC instruction. This indicates the actual active power generated by the photovoltaic power station. This indicates the maximum active power that the wind power station can generate. This indicates the minimum active power that a wind power station can generate. This indicates the maximum charging power of the energy storage power station. This indicates the maximum discharge capacity of the energy storage power station.

[0014] Optionally, if the wind power station is in the centralized control mode and the photovoltaic power station and energy storage power station are in the direct grid dispatch mode, then the step of allocating the station execution command to the corresponding power station in the centralized control mode includes: calculating the command deviation between the actual active power generated at the current grid connection point and the AGC command; if the command deviation is greater than the preset allowable deviation dead zone for the wind power station, then the station execution command is allocated to the wind power station according to the following formula.

[0015]

[0016] In the formula, This indicates the portion of the wind power plant that is allocated from the site according to the instructions. This indicates that the station is executing instructions, and This refers to the AGC instruction. This indicates the actual active power generated by the photovoltaic power station. This indicates the actual active power generated by the energy storage power station. This indicates the maximum active power that the wind power station can generate. This indicates the minimum active power that a wind power station can generate.

[0017] Optionally, the method further includes: when the SOC of the energy storage power station reaches within a preset distance of the currently set upper limit of SOC or lower limit of SOC, interpolating the maximum discharge power or maximum charging power of the energy storage power station.

[0018] According to a second aspect, embodiments of the present invention provide a coordinated control device for primary frequency regulation and AGC, the device comprising: a primary frequency regulation start-up determination module, used to determine whether primary frequency regulation control is initiated; a first energy storage parameter setting module, used to, if primary frequency regulation control is not initiated, set the upper and lower limits of the SOC of the energy storage power station to be put into operation as a first limit and a second limit, respectively, and reserve a preset proportional capacity not to participate in power output; a first instruction allocation module, used to acquire AGC instructions and allocate the AGC instructions to the wind power station, the photovoltaic power station and the energy storage power station for execution; a second energy storage parameter setting module, used to, if primary frequency regulation control is initiated, set the upper and lower limits of the SOC of the energy storage power station to be put into operation as a third limit and a fourth limit, respectively, and release all capacity to participate in power output; and a second instruction allocation module, used to calculate the primary frequency regulation instruction increment, and after superimposing the primary frequency regulation instruction increment with the acquired AGC instruction, allocate it to the wind power station, the photovoltaic power station and the energy storage power station for execution; wherein the third limit is higher than the first limit, and the fourth limit is lower than the second limit.

[0019] According to a third aspect, embodiments of the present invention provide an electronic device, including: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to perform the method described in the first aspect, or any optional embodiment of the first aspect.

[0020] According to a fourth aspect, embodiments of the present invention provide a computer-readable storage medium storing computer instructions for causing the computer to perform the method described in the first aspect, or any alternative embodiment of the first aspect.

[0021] The technical solution provided in this application has the following advantages:

[0022] The technical solution provided in this application comprehensively considers factors affecting energy storage lifespan, such as the state of charge (SOC) and power surges, and carefully manages each energy storage output. It utilizes a frequency regulation control strategy with varying SOC to simultaneously extend energy storage lifespan and ensure grid frequency does not exceed limits. When the power station is not under primary frequency regulation control, the upper and lower limits of the SOC for the energy storage station are set as a first limit with a lower upper limit and a second limit with a higher lower limit. A preset proportional capacity is reserved for primary frequency regulation and does not participate in the current output. Then, the secondary frequency regulation AGC command is distributed to the wind power station, solar power station, and energy storage station for execution, reducing the use of the energy storage station and extending its lifespan. When primary frequency regulation control is implemented, the upper and lower limits of the SOC for the energy storage station are set as a third limit with a higher upper limit and a fourth limit with a lower lower limit, and all capacity is allowed to participate in output, thereby ensuring grid frequency does not exceed limits. Through the control steps provided in this embodiment, a coordinated control scheme for primary frequency regulation and AGC that balances energy storage lifespan and frequency regulation objectives is achieved.

[0023] Furthermore, in one embodiment, considering the potential increase in grid connection point volatility due to wind and solar power fluctuations and the dynamic characteristics of power station regulation, if the primary frequency regulation is involved in the control process, when the primary frequency regulation exits the control process, the AGC commands allocated to the wind power station, solar power station, and energy storage station in the previous control cycle are also acquired. The command difference between the AGC commands allocated to the wind power station, solar power station, and energy storage station in the current control cycle and those allocated in the previous control cycle is calculated. Then, based on the relationship between this command difference and the preset command change dead zone, and the relationship between this command difference and the preset active power command change step size, it is determined whether the AGC commands of the current control cycle need correction. If correction is needed, the AGC commands of the current control cycle are adjusted according to the corresponding correction strategy. Through the above correction steps, the impact of wind and solar power fluctuations and the dynamic characteristics of power station regulation on power quality is reduced, the power surge during primary frequency regulation exit is minimized, and a seamless switching between primary frequency regulation and AGC control is achieved. Attached Figure Description

[0024] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings:

[0025] Figure 1 A schematic diagram illustrating the steps of a coordinated control method for primary frequency modulation and AGC in one embodiment of the present invention is shown.

[0026] Figure 2 A flowchart illustrating a coordinated control method for primary frequency modulation and AGC according to one embodiment of the present invention is shown.

[0027] Figure 3A schematic diagram of test results is shown in one embodiment of the present invention, without considering the impact of a single frequency modulation exit.

[0028] Figure 4 A schematic diagram of test results considering the impact of a primary frequency modulation exit is shown in one embodiment of the present invention;

[0029] Figure 5 A schematic diagram of the structure of a coordinated control device for primary frequency modulation and AGC in one embodiment of the present invention is shown;

[0030] Figure 6 A schematic diagram of an electronic device according to one embodiment of the present invention is shown. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Please see Figure 1 In one implementation, the coordinated control method for primary frequency modulation and AGC specifically includes the following steps:

[0033] Step S101: Determine whether to enter primary frequency modulation control.

[0034] Step S102: If the primary frequency regulation control is not entered, the upper and lower limits of the SOC of the energy storage power station are set as the first limit and the second limit, respectively, and a preset proportional capacity is reserved to not participate in the output.

[0035] Step S103: Obtain AGC instructions and assign AGC instructions to wind power plants, solar power plants and energy storage power plants for execution.

[0036] Step S104: If the primary frequency regulation control is entered, the upper and lower limits of the SOC of the energy storage power station are set to the third and fourth limits respectively, and all capacity is allowed to participate in power output.

[0037] Step S105: Calculate the primary frequency regulation command increment, and then add the primary frequency regulation command increment to the acquired AGC command, and distribute it to the wind power station, solar power station, and energy storage power station for execution. The third limit is higher than the first limit, and the fourth limit is lower than the second limit.

[0038] Specifically, the embodiments of the present invention comprehensively consider factors affecting the lifespan of energy storage, such as the energy storage SOC and energy storage power surge, and carefully manage each energy storage output. By utilizing a frequency regulation control strategy with variable SOC, the goal of extending the lifespan of energy storage and ensuring that the grid frequency does not exceed the limit can be achieved simultaneously.

[0039] First, it is necessary to determine whether frequency regulation should be involved within the current control cycle. Before this step, data acquisition is performed, as the acquired data is essential for executing the calculations of the current and subsequent steps. The system monitors variables such as frequency, current, voltage, and active power at the grid connection point in real time, and monitors parameters such as active power, maximum available active power, and minimum available active power of wind power stations, solar power stations, and energy storage stations, and presets relevant parameters. Specifically, the required parameters include the actual active power generated by wind power stations, solar power stations, and energy storage stations. Simultaneously, the frequency, current, voltage, and actual active power generated at the grid connection point of wind, solar, and energy storage stations are sampled and transmitted to the controller via communication for real-time strategy judgment. Multiple parameters are preset, including the system rated frequency f. N (typically 50Hz), percentage of reserved energy storage capacity, dead zone f of primary frequency regulation. D1 The droop rate δ% of the primary frequency regulation control is preset with a limit on the change in active power at the wind and solar power storage station. The limit for active power variation at wind and solar power storage stations has been lowered. Active power command change step size for wind power plants, active power command change step size for solar power plants, and maximum active power output of wind power plants. Minimum active power generated by a wind power station Maximum active power generated by a photovoltaic power station Minimum active power output of a photovoltaic power station Active power command change step size of energy storage power station, active power command change dead zone of wind power station, active power command change dead zone of photovoltaic power station, active power command change dead zone of energy storage power station, maximum discharge power of energy storage power station. Maximum charging capacity of energy storage power station (It should be noted that,) The physical meaning of is the maximum chargeable power of the current energy storage power station. This value is a positive scalar. When a negative sign is added in front of this value, it indicates that the direction of charging needs to be distinguished from discharging (charging is negative). The state of charge (SOC) of the energy storage system.

[0040] Next, it is determined whether the deviation between the current grid connection point frequency and the system rated frequency exceeds the preset dead zone f for primary frequency regulation. D1 If the dead zone is exceeded, the system enters integrated control of primary and secondary frequency modulation; otherwise, it enters conventional secondary frequency modulation control. This process determines whether to enter primary frequency modulation control. This step is existing technology, and the specific principle will not be elaborated here.

[0041] If primary frequency regulation control is not initiated, in the current scenario, the upper and lower limits of the energy storage SOC will be automatically adjusted to the lower first limit and the higher second limit, respectively. For example, the upper and lower limits are 0.8 and 0.2 respectively (this is just an example and not a limitation). A preset proportion of energy storage capacity (e.g., 10%) is reserved for primary frequency regulation, meaning 90% of the energy storage system's capacity is used for secondary frequency regulation and 10% for primary frequency regulation. This improves the lifespan of the energy storage station, maintains its performance, and ensures that the energy storage station can better support the primary frequency regulation of the grid when it participates, without affecting the effectiveness of primary frequency regulation due to a decline in energy storage performance. Then, the secondary frequency regulation AGC commands can be distributed to the wind power station, solar power station, and energy storage station for execution.

[0042] If the deviation between the current grid connection frequency and the system rated frequency exceeds the dead zone f of the primary frequency regulation, D1 Then, primary frequency regulation control is initiated. In the current scenario, the upper and lower limits of the energy storage SOC are automatically adjusted to the higher third limit and the lower fourth limit, for example, the upper and lower limits are 0.9 and 0.1 respectively; and the preset proportion (e.g., 10%) of the energy storage capacity reserved for primary frequency regulation in secondary frequency regulation is used up. Thus, by using energy storage at full output, the effectiveness of primary and secondary frequency regulation is guaranteed, ensuring that the grid frequency does not exceed the limit.

[0043] Furthermore, in this embodiment, the frequency modulation command increment ΔP1 is calculated according to the following formula.

[0044]

[0045] In the formula, ΔP1 is the increment value of the active power command under primary frequency regulation control, P n f is the rated power of the wind-solar-storage station. N f is the system's rated frequency. D1 δ% represents the dead zone boundary value of the primary frequency regulation control, and δ% represents the droop rate of the primary frequency regulation control of the wind and solar power storage station.

[0046] Then, the primary frequency regulation command increment ΔP1 is transmitted to the coordination control module of primary frequency regulation and AGC for command superposition. Superposition follows the principle of primary frequency regulation priority, meaning the adjustment direction of the current AGC command is determined based on the current AGC command value and the actual active power generation at the wind, solar, and energy storage power station grid connection point. If the adjustment direction of the AGC command and the primary frequency regulation command increment are the same, they are directly superimposed; otherwise, AGC control is blocked, and only the primary frequency regulation command is responded to. Finally, the final active power control command for the wind, solar, and energy storage power station is obtained and issued to the wind power station / solar power station / energy storage power station according to the principle of energy storage priority adjustment. That is, energy storage is used first to meet the current active power regulation demand; only when the energy storage adjustment margin is insufficient is the solar power station used to respond to the active power regulation demand; and finally, the wind power station participates in regulation. Thus, based on the rapid adjustment advantage of the energy storage power station itself, the speed of frequency regulation is ensured when responding to primary frequency regulation, thereby ensuring the safety of grid operation.

[0047] Through the frequency regulation control strategy of variable SOC described above, this embodiment of the invention provides a coordinated control scheme that can take into account both energy storage lifetime and frequency regulation target.

[0048] Specifically, such as Figure 2 As shown, in one embodiment, the coordinated control method for primary frequency modulation and AGC provided by this invention further includes the following steps:

[0049] Step 1: After entering primary frequency control, determine whether to exit primary frequency control.

[0050] Step 2: If the frequency regulation control is exited, the AGC instructions allocated to the wind power station, solar power station and energy storage power station in the previous control cycle are obtained.

[0051] Step 3: Calculate the instruction difference between the AGC instructions allocated to each of the wind power station, solar power station, and energy storage power station in the current control cycle and the AGC instructions allocated in the previous control cycle.

[0052] Step 4: If any instruction difference is less than the preset instruction change dead zone, the AGC instruction allocated in the current control cycle of the corresponding power station will be corrected to the AGC instruction allocated in the previous control cycle.

[0053] Step 5: If any instruction difference is greater than the preset active power instruction change step size, the AGC instruction allocated in the current control cycle of the corresponding power station will be corrected to the sum of the AGC instruction allocated in the previous control cycle and the preset active power instruction change step size in the control direction.

[0054] Specifically, to reduce grid connection point fluctuations caused by significant adjustments in wind power plants, solar power plants, and energy storage power plants, while ensuring that these plants are not subject to power surges and minimizing the impact of deep charging and discharging on energy storage power plants, a safe operation module was designed to execute steps one through five above. This module ensures the stability of wind power plants, solar power plants, and energy storage power plants during secondary frequency regulation and guarantees a reduction in the active power fluctuation rate at the grid connection point when primary frequency regulation control is withdrawn. This is achieved when the frequency deviation between the current grid connection point frequency and the system rated frequency is less than the preset primary frequency regulation dead zone f. D1 At this time, it is necessary to exit frequency modulation control once.

[0055] When exiting frequency regulation control, firstly, the actual power generation values ​​and allocated AGC command values ​​of the wind power station, solar power station, and energy storage station in the previous control cycle are recorded. Then, the AGC command values ​​issued to the wind power station, solar power station, and energy storage station in the current control cycle are collected in real time. Since the command values ​​from the previous control cycle cannot be collected during the first cycle of operation of the wind-solar-storage power station, it is necessary to determine whether the current cycle is the first cycle of operation. If it is, the active power command value from the previous control cycle is set equal to the current actual power generation value; otherwise, the command value from the previous cycle is collected normally.

[0056] The second step involves calculating the difference between the AGC commands allocated to each of the wind power station, solar power station, and energy storage power station in the current control cycle and those allocated in the previous control cycle. This calculated difference is then compared with a preset command change dead zone and a preset active power command change step size. If the difference is less than the preset command change dead zone, it indicates that the magnitude of the current command change is too small, and even without a command change, it will not significantly affect the power output of the power station. Therefore, the AGC commands allocated to the corresponding power station in the current control cycle are corrected to those allocated in the previous control cycle, reducing frequency fluctuations at the grid connection point. For example, after calculating the difference between the AGC commands allocated to the wind power station in the current control cycle and those allocated in the previous control cycle, the difference is compared with the preset command change dead zone. If the difference is less than the preset dead zone, the wind power station will not execute the AGC commands allocated in the current control cycle but will continue to execute the AGC commands allocated in the previous control cycle. Furthermore, the command difference between each power station is compared with the preset active power command change step size. If the command difference is greater than the preset active power command change step size, it indicates that the AGC command change in the current control cycle is too large. In order to reduce the frequency fluctuation at the grid connection point, the AGC command of the corresponding power station is updated in the control direction according to "AGC command allocated in the current control cycle = AGC command allocated in the previous control cycle + preset active power command change step size". If the command difference of the corresponding power station is between the above two value ranges, the power station can maintain the AGC command allocated in the previous control cycle. Through the above steps, this embodiment reduces the power surge when frequency regulation exits and achieves a seamless handover.

[0057] Specifically, in one embodiment, step S103 above includes the following steps:

[0058] Step 6: Obtain the control modes of the wind power station, solar power station and energy storage power station respectively, and determine whether the AGC command is valid. The control modes include the station centralized control mode, the grid direct control mode and the exit control mode.

[0059] Step 7: If the AGC command is valid, calculate the difference between the AGC command and the actual active power generated by the corresponding power station under the grid direct dispatch mode to obtain the station execution command.

[0060] Step 8: Assign the station execution command to the corresponding power station in the station centralized control mode.

[0061] Specifically, this embodiment of the invention provides a specific control strategy for frequency regulation. For wind power plants, solar power plants, and energy storage power plants operating in different modes, the system calculates the actual station execution commands that the power plants operating only in the station centralized control mode need to execute, and then allocates the station execution commands to improve the accuracy of command allocation.

[0062] Among them, the centralized control mode of the wind, solar and energy storage power station represents the power station executing the instructions issued by the control strategy of the wind, solar and energy storage power station; the direct grid dispatch mode represents the power station directly receiving the control instructions issued by the grid. In other words, the control of the power station no longer belongs to the wind, solar and energy storage power station, so these instructions need to be excluded when the power station performs secondary frequency regulation; if the power station is operating in the exit control mode, it means that the power station does not accept any instructions. Combining the three types of power stations (wind power station, solar power station and energy storage power station) and the three operating modes (centralized control, direct grid dispatch and exit control), a total of 27 AGC instruction allocation strategies can be formed, as shown in Table 1. In the table, 0 represents the centralized control mode, 1 represents the direct grid dispatch mode, and 2 represents the exit control mode.

[0063] Table 1. Summary of Control Methods for AGC Participation in Regulation at Wind, Solar and Storage Power Stations

[0064]

[0065]

[0066] For example, if the wind power station, solar power station, and energy storage station operate in mode 8, then the wind power station is in centralized control mode, the energy storage station is in direct grid control mode, and the solar power station is in out-of-control mode. Therefore, neither the solar power station nor the energy storage station participates in the allocation of AGC commands. Furthermore, when allocating AGC commands to the wind power station, the actual generated power of the energy storage station needs to be deducted. That is, the AGC command issued by the grid connection point minus the actual active power generated by the energy storage station yields the grid execution command. The wind power station only receives this portion of the grid execution command based on its own operating conditions. Based on the above steps, when the validity verification of the AGC command passes, this embodiment provides 27 command allocation strategies, meeting the processing needs of all scenarios.

[0067] Specifically, in one embodiment, step six above includes the following steps:

[0068] Step 9: Determine whether the active power data of the grid connection point stops refreshing within the preset time interval.

[0069] Step 10: If refreshing stops, it indicates that the AGC command is invalid.

[0070] Step 11: If the refresh does not stop, determine whether the actual active power generated at the grid connection point is greater than the preset multiple of the total capacity of the entire power station or less than 0.

[0071] Step 12: If the actual active power generated at the grid connection point is greater than a preset multiple of the total capacity of the entire power station or less than 0, then the AGC command is determined to be invalid.

[0072] Specifically, in this embodiment, it is first determined whether the active power data of the grid-connected point has stopped refreshing within a preset time interval. If it has not been refreshed, the AGC command to be allocated is invalid. This is because the large fluctuations in wind and solar power cause the actual active power output of the grid-connected point to fluctuate continuously. If it does not refresh within a certain time interval, it indicates a problem in the data sampling process, and all currently collected data loses its reliability. Consequently, the AGC command generated based on the collected data also loses its feasibility, and it is necessary to stop entering AGC control in time to ensure the reliability of the power system. Afterward, if the active power data of the grid-connected point does not stop refreshing, it is further determined whether the actual active power generated by the grid-connected point is greater than a preset multiple (e.g., 1.3 times) or less than 0 of the total capacity of the entire power station. If the actual active power generated by the grid-connected point is greater than a preset multiple of the total capacity of the entire power station or less than 0, it is considered that the AGC command to be allocated has exceeded the adjustable range of the entire station and is an unreliable command. If it is followed rashly, it may cause increased frequency fluctuations, thus determining that the AGC command to be allocated is invalid.

[0073] Specifically, in one embodiment, if the wind power station and energy storage power station are in the site centralized control mode, and the photovoltaic power station is in the grid direct dispatch mode, then step eight above specifically includes the following steps:

[0074] Step 13: Calculate the actual active power generated at the current grid connection point and the instruction deviation between the AGC instruction;

[0075] Step Fourteen: If the command deviation exceeds the preset allowable dead zone for the wind farm, then allocate the wind farm execution command according to the following formula.

[0076]

[0077] And allocate site execution instructions to the energy storage power station according to the following formula.

[0078]

[0079] In the formula, This indicates the portion of the wind power plant that is allocated from the site according to the instructions. This indicates that the station is executing instructions, and This indicates the AGC command. This indicates the actual active power generated by the photovoltaic power station. This indicates the maximum active power that the wind power station can generate. This indicates the minimum active power that a wind power station can generate. This indicates the maximum charging power of the energy storage power station. This indicates the maximum discharge capacity of the energy storage power station.

[0080] Specifically, this embodiment of the invention provides a specific AGC command allocation strategy for wind power plants and energy storage power plants in site centralized control mode, and photovoltaic power plants in grid direct dispatch mode, thereby further improving the accuracy of AGC command allocation. First, the actual active power generated at the current grid connection point is calculated. and AGC instructions for grid connection points Deviation between

[0081]

[0082] If the current deviation is less than the preset allowable deviation dead zone of the site, the current instruction remains unchanged to avoid excessively frequent instructions and increased burden on the site; if the current deviation is greater than the preset allowable deviation dead zone of the site, proceed to the next step of AGC instruction allocation.

[0083] Since wind power stations and energy storage power stations are in a centralized control mode at the site, it is necessary to calculate the actual site execution commands. This means deducting the actual power output of the photovoltaic power station from the AGC command. Then, the power station executes the command. The allocation is made to wind power plants and energy storage power plants. The specific meanings of the above two sets of allocation strategy formulas are explained below:

[0084] Regarding the formula

[0085]

[0086] The explanation.

[0087] When it appears This indicates that both the wind power station and the energy storage station need to generate electricity together to meet the site's execution commands. Therefore, the current wind power station command is the maximum active power that the wind power station can generate at present. To ensure the minimum wind curtailment rate; if currently and This indicates that the current wind farm can fulfill the execution commands on its own, and can utilize the charging characteristics of energy storage to receive excess power, thus simultaneously achieving low wind curtailment rate and tracking accuracy. Therefore, the current commands given to the wind farm are still based on its maximum available active power. If the current (It should be noted that,) The physical meaning of this value is the maximum chargeable power of the current energy storage power station. This value is a positive scalar, but a negative sign is added to distinguish between charging and discharging (charging is negative). This indicates that even though the energy storage is charging at maximum power, the wind power station will still generate excess energy, thus requiring power limiting to ensure tracking accuracy. Therefore, the current wind power station command is set to... To ensure tracking accuracy; at the same time, it is also necessary to judge Is it greater than If it is greater than, it means that the current command value is not lower than the minimum active power generation value of the wind power station. according to Output power is sufficient; if it is less than the specified value, it indicates that the current command has exceeded the wind power station's regulation range, and the minimum active power output of the wind power station should be used. To generate electricity and avoid excessive frequency fluctuations at the grid connection point.

[0088] Regarding the formula

[0089]

[0090] The explanation.

[0091] If the current This indicates that energy storage power generation is currently needed to ensure tracking accuracy, and if This indicates that even if energy storage discharges at its maximum discharge power, it cannot keep up with the grid's commands. Therefore, energy storage must currently discharge at its maximum discharge power. if and This indicates that current energy storage power stations do not need to discharge at their maximum discharge power. The instructions for the energy storage power station are set as follows: If the current This indicates that the charging characteristics of energy storage can be utilized to simultaneously meet the requirements of low wind curtailment rate and tracking accuracy; further judgment is needed. Is it greater than If greater than This indicates that the energy storage does not need to be charged at its maximum chargeable active power, and the command for the energy storage power station is set to... If the current The instruction states that to maintain the current low wind curtailment rate, energy storage power stations need to charge at their maximum chargeable power.

[0092] Specifically, in one embodiment, if the wind power station is in the site centralized control mode and the photovoltaic power station and energy storage power station are in the grid direct dispatch mode, then step eight above specifically includes the following steps:

[0093] Step 15: Calculate the actual active power generated at the current grid connection point and the instruction deviation between the AGC instruction and the instruction.

[0094] Step 16: If the command deviation exceeds the preset allowable dead zone for the wind farm, then allocate the wind farm execution command according to the following formula.

[0095]

[0096] In the formula, This indicates the portion of the wind power plant that is allocated from the site according to the instructions. This indicates that the station is executing instructions, and This indicates the AGC command. This indicates the actual active power generated by the photovoltaic power station. This indicates the actual active power generated by the energy storage power station. This indicates the maximum active power that the wind power station can generate. This indicates the minimum active power that a wind power station can generate.

[0097] Specifically, this embodiment of the invention also provides a specific AGC command allocation strategy for situations where only wind power plants are in site centralized control mode, while photovoltaic power plants and energy storage power plants are in grid direct dispatch mode, thereby further improving the accuracy of AGC command allocation. First, the actual active power generated at the current grid connection point is calculated. and AGC instructions for grid connection points Deviation between

[0098]

[0099] If the current deviation is less than the preset station allowable deviation dead zone, the current instruction remains unchanged; if the current deviation is greater than the preset station allowable deviation dead zone, proceed to the next AGC instruction allocation.

[0100] Since wind power stations and energy storage power stations are in a centralized control mode at the site, it is necessary to calculate the actual site execution commands. This involves deducting the actual power output of the photovoltaic power station and energy storage power station from the AGC command. Then, the site executes the command. Allocated only to wind farms. The farm will execute instructions during allocation. With the wind field's maximum potential active power Minimum active power generated by the wind field If the comparison is made and the results exceed two thresholds, the wind farm needs to be instructed to generate power according to the maximum active power capacity of the wind farm. Or the minimum wind field can generate active power If the wind power generation falls within this range, all actual field execution instructions can be assigned to the wind power station for execution, thereby ensuring both the minimum wind curtailment rate and tracking accuracy of the wind power station.

[0101] Specifically, in one embodiment, the coordinated control method for primary frequency modulation and AGC provided by the present invention further includes the following steps:

[0102] Step 17: When the SOC of the energy storage power station reaches within the preset distance of the currently set upper or lower limit of SOC, interpolate the maximum discharge power or maximum charging power of the energy storage power station.

[0103] Specifically, in AGC control, when the SOC state of the energy storage power station approaches the upper and lower limits, this embodiment of the invention performs interpolation processing on the maximum power generation of the energy storage system and the minimum power generation of the energy storage station. Assuming that the upper and lower limits of SOC are 0.8 and 0.2 respectively, the interpolation processing is as shown in the following formula, thereby ensuring that the energy storage power station can slowly return to zero, avoiding the sudden shutdown of the energy storage power station, and further improving the lifespan of the energy storage power station.

[0104]

[0105] In the formula, This indicates the maximum or minimum generating capacity of the energy storage power station.

[0106] Specifically, in one application embodiment, a real-time, high-precision simulation is performed using the existing Real-Time Digital System (RTDS) model of the wind, solar, and energy storage power station and grid structure. The wind power rated power is set at 425MW, with a reserved capacity of 10% of the rated wind power, resulting in a wind power generation capacity of 382.5MW; the solar power rated power is 75MW, with a reserved capacity of 10% of the rated solar power, resulting in a solar power generation capacity of 67.5MW; and the energy storage rated power is ±140MW. The power grid issues power curtailment commands at 180-second intervals, with the commands sequentially setting the total rated power of wind, solar, and energy storage to 80%, 60%, 40%, 20%, 40%, 60%, and 80%. After the grid issues the commands, it is determined that the frequency has not exceeded the dead zone and that the commands are not abnormal, then the system enters conventional secondary frequency regulation control. In this process, wind power, solar power, and energy storage are regulated according to the dispatch commands, and wind power and solar power generate electricity at their maximum power tracking points to minimize wind and solar curtailment rates. Through testing and verification, based on the technical solution provided in this application, when the power command issued by the power grid changes, the actual active power generated by the entire station can track the active power command of the entire station relatively well.

[0107] In addition, this embodiment also tested the effectiveness of exiting AGC control via frequency modulation. At the 19th second, a down-modulated frequency signal of 49.85Hz was emitted using a signal generator and lasted for 20 seconds. Figure 3 The test results do not consider the impact of a single frequency modulation exit. Figure 4 This is a test result considering the impact of a single frequency modulation shutdown. Comparative observation. Figure 3 and Figure 4 It is not difficult to see that the embodiments of the present invention take into account the impact on the active power of the grid connection point when the frequency regulation is withdrawn. When the frequency returns to the normal range, the energy storage drops to the target value in two steps according to the set step size (15MW in this case). Compared with the prior art, the frequency fluctuation of the grid connection point is greatly reduced, which improves the stability and friendliness of the wind, solar and energy storage station to the power system and realizes the worry-free switching of the primary frequency regulation.

[0108] Through the above steps, the technical solution provided in this application comprehensively considers factors affecting energy storage lifespan, such as the state of charge (SOC) and power surges, and carefully manages each energy storage output. Utilizing a frequency regulation control strategy with varying SOC, it simultaneously achieves the goals of extending energy storage lifespan and ensuring the grid frequency does not exceed limits. When the power station is not under primary frequency regulation control, the upper and lower limits of the SOC for the energy storage station are set as a first limit with a lower upper limit and a second limit with a higher lower limit, respectively. A preset proportional capacity is reserved for primary frequency regulation and does not participate in this output. Then, the secondary frequency regulation AGC command is distributed to the wind power station, solar power station, and energy storage station for execution, reducing the use of the energy storage station and improving its lifespan. When primary frequency regulation control is implemented, the upper and lower limits of the SOC for the energy storage station are set as a third limit with a higher upper limit and a fourth limit with a lower lower limit, respectively. All capacity is released to participate in output, thereby ensuring the grid frequency does not exceed limits. Through the control steps provided in this embodiment, a coordinated control scheme for primary frequency regulation and AGC that balances energy storage lifespan and frequency regulation goals is achieved.

[0109] Furthermore, in one embodiment, considering the potential increase in grid connection point volatility due to wind and solar power fluctuations and the dynamic characteristics of power station regulation, if the primary frequency regulation is involved in the control process, when the primary frequency regulation exits the control process, the AGC commands allocated to the wind power station, solar power station, and energy storage station in the previous control cycle are also acquired. The command difference between the AGC commands allocated to the wind power station, solar power station, and energy storage station in the current control cycle and those allocated in the previous control cycle is calculated. Then, based on the relationship between this command difference and the preset command change dead zone, and the relationship between this command difference and the preset active power command change step size, it is determined whether the AGC commands of the current control cycle need correction. If correction is needed, the AGC commands of the current control cycle are adjusted according to the corresponding correction strategy. Through the above correction steps, the impact of wind and solar power fluctuations and the dynamic characteristics of power station regulation on power quality is reduced, the power surge during primary frequency regulation exit is minimized, and a seamless switching between primary frequency regulation and AGC control is achieved.

[0110] like Figure 5 As shown, this embodiment also provides a coordinated control device for primary frequency modulation and AGC, the device comprising:

[0111] The primary frequency modulation start determination module 101 is used to determine whether to enter primary frequency modulation control. For details, please refer to the relevant description of step S101 in the above method embodiment, which will not be repeated here.

[0112] The first energy storage parameter setting module 102 is used to set the upper and lower limits of the State of Charge (SOC) for the energy storage power station to be put into operation as the first limit and the second limit, respectively, if the primary frequency regulation control is not entered, and to reserve a preset proportional capacity that will not participate in power output. For details, please refer to the relevant description of step S102 in the above method embodiment, which will not be repeated here.

[0113] The first instruction allocation module 103 is used to acquire AGC instructions and allocate them to wind power plants, photovoltaic power plants, and energy storage power plants for execution. For details, please refer to the relevant description of step S103 in the above method embodiments, which will not be repeated here.

[0114] The second energy storage parameter setting module 104 is used to set the upper and lower limits of the State of Charge (SOC) for the energy storage power station to be put into operation as the third and fourth limits, respectively, and to allow all capacity to participate in power output if primary frequency regulation control is entered. For details, please refer to the relevant description of step S104 in the above method embodiment, which will not be repeated here.

[0115] The second instruction allocation module 105 calculates the primary frequency regulation instruction increment, and then adds the primary frequency regulation instruction increment to the acquired AGC instruction before allocating it to the wind power station, solar power station, and energy storage power station for execution. For details, please refer to the relevant description of step S105 in the above method embodiment, which will not be repeated here.

[0116] The third boundary is higher than the first boundary, and the fourth boundary is lower than the second boundary.

[0117] The primary frequency modulation and AGC coordination control device provided in this embodiment of the invention is used to execute the primary frequency modulation and AGC coordination control method provided in the above embodiment. Its implementation method and principle are the same. For details, please refer to the relevant description of the above method embodiment, which will not be repeated here.

[0118] Figure 6 An electronic device according to an embodiment of the present invention is shown. The device includes a processor 901 and a memory 902, which can be connected via a bus or other means. Figure 6 Taking the example of a connection between China and Israel via a bus.

[0119] Processor 901 can be a Central Processing Unit (CPU). Processor 901 can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations of the above types of chips.

[0120] The memory 902, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the methods in the above method embodiments. The processor 901 executes various functional applications and data processing of the processor by running the non-transitory software programs, instructions, and modules stored in the memory 902, thereby implementing the methods in the above method embodiments.

[0121] The memory 902 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the processor 901, etc. Furthermore, the memory 902 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 902 may optionally include memory remotely located relative to the processor 901, and these remote memories may be connected to the processor 901 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0122] One or more modules are stored in memory 902, and when executed by processor 901, they perform the methods described in the above method embodiments.

[0123] The specific details of the aforementioned electronic device can be understood by referring to the relevant descriptions and effects in the above method embodiments, and will not be repeated here.

[0124] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The implemented program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.

[0125] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A coordinated control method for primary frequency modulation and AGC, characterized in that, The method includes: Determine whether to enter primary frequency modulation control; If it does not enter the primary frequency regulation control, the upper and lower limits of the SOC of the energy storage power station are set as the first limit and the second limit, respectively, and a preset proportional capacity is reserved that does not participate in the output. The process involves acquiring an AGC command and assigning it to a wind power station, a solar power station, and an energy storage station for execution. Assigning the AGC command to these stations includes: acquiring the control modes of each station and determining whether the AGC command is valid; the control modes include a centralized control mode, a direct grid control mode, and a control exit mode; if the AGC command is valid, calculating the difference between the AGC command and the actual active power generated by the corresponding station under the direct grid control mode to obtain the station execution command; and assigning the station execution command to the corresponding station under the centralized control mode. The determination of whether the AGC command is valid includes: determining whether the active power data of the grid-connected point stops refreshing within a preset time interval; if refreshing stops, the AGC command is determined to be invalid; if refreshing does not stop, determining whether the actual active power generated by the grid-connected point is greater than a preset multiple of the total capacity of the entire power station or less than 0; if the actual active power generated by the grid-connected point is greater than a preset multiple of the total capacity of the entire power station or less than 0, the AGC command is determined to be invalid. If the wind power station and energy storage power station are in the centralized control mode, and the photovoltaic power station is in the direct grid dispatch mode, then the step of allocating the station execution command to the corresponding power station in the centralized control mode includes: calculating the command deviation between the actual active power generated at the current grid connection point and the AGC command; if the command deviation is greater than the preset allowable deviation dead zone for the station, then the station execution command is allocated to the wind power station according to the following formula. And allocate site execution instructions to the energy storage power station according to the following formula. In the formula, This indicates the portion of the energy storage power station allocated from the site according to the instructions executed. This indicates the portion of the wind power plant that is allocated from the site according to the instructions. This indicates that the station is executing instructions, and , This refers to the AGC instruction. This indicates the actual active power generated by the photovoltaic power station. This indicates the maximum active power that the wind power station can generate. This indicates the minimum active power that a wind power station can generate. This indicates the maximum charging power of the energy storage power station. This indicates the maximum discharge capacity of the energy storage power station; If the wind power station is in centralized control mode and the photovoltaic power station and energy storage power station are in direct grid dispatch mode, then the step of allocating the station execution command to the corresponding power station in centralized control mode includes: calculating the command deviation between the current active power generated at the grid connection point and the AGC command; if the command deviation is greater than the preset allowable dead zone for the station, then the station execution command is allocated to the wind power station according to the following formula. In the formula, This indicates the portion of the wind power plant that is allocated from the site according to the instructions. This indicates that the station is executing instructions, and , This refers to the AGC instruction. This indicates the actual active power generated by the photovoltaic power station. This indicates the actual active power generated by the energy storage power station. This indicates the maximum active power that the wind power station can generate. This indicates the minimum active power that a wind power station can generate; If the system enters the primary frequency regulation control, the upper and lower limits of the SOC for the energy storage power station to be put into operation are set to the third and fourth limits, respectively, and the full capacity is allowed to participate in power output. Calculate the first frequency regulation command increment, and then superimpose the first frequency regulation command increment with the acquired AGC command, and allocate it to the wind power station, the photovoltaic power station and the energy storage power station for execution; The third boundary is higher than the first boundary, and the fourth boundary is lower than the second boundary.

2. The method according to claim 1, characterized in that, The method further includes: After entering a frequency modulation control, determine whether to exit the frequency modulation control; If the frequency regulation control is exited, the AGC instructions allocated to the wind power station, solar power station and energy storage power station in the previous control cycle will be obtained. Calculate the instruction difference between the AGC instructions allocated to each of the wind power station, solar power station, and energy storage power station in the current control cycle and the AGC instructions allocated to each of them in the previous control cycle. If any instruction difference is less than the preset instruction change dead zone, the AGC instruction allocated in the current control cycle of the corresponding power station will be corrected to the AGC instruction allocated in the previous control cycle. If any instruction difference is greater than the preset active power instruction change step size, the AGC instruction allocated in the current control cycle of the corresponding power station will be corrected to the sum of the AGC instruction allocated in the previous control cycle and the preset active power instruction change step size in the control direction.

3. The method according to claim 1, characterized in that, The method further includes: When the SOC of the energy storage power station reaches within a preset distance of the currently set upper or lower limit of SOC, the maximum discharge power or maximum charging power of the energy storage power station is interpolated.

4. A coordinated control device for primary frequency modulation and AGC, characterized in that, The device includes: The primary frequency modulation start-up determination module is used to determine whether to enter primary frequency modulation control; The first energy storage parameter setting module is used to set the upper and lower limits of the SOC of the energy storage power station to be put into operation as the first limit and the second limit, respectively, if it does not enter the primary frequency regulation control, and to reserve a preset proportional capacity that does not participate in the output. The first instruction allocation module is used to acquire AGC instructions and allocate the AGC instructions to the wind power station, the solar power station, and the energy storage station for execution. The allocation of the AGC instructions to the wind power station, the solar power station, and the energy storage station includes: acquiring the control modes of each of the wind power station, the solar power station, and the energy storage station, and determining whether the AGC instructions are valid. The control modes include a site centralized control mode, a grid direct dispatch mode, and a control exit mode. If the AGC instructions are valid, the difference between the AGC instructions and the actual active power generated by the corresponding power station under the grid direct dispatch mode is calculated to obtain the site execution instructions. The site execution instructions are then allocated to the corresponding power station under the site centralized control mode for execution. The determination of whether the AGC command is valid includes: determining whether the active power data of the grid-connected point stops refreshing within a preset time interval; if refreshing stops, the AGC command is determined to be invalid; if refreshing does not stop, determining whether the actual active power generated by the grid-connected point is greater than a preset multiple of the total capacity of the entire power station or less than 0; if the actual active power generated by the grid-connected point is greater than a preset multiple of the total capacity of the entire power station or less than 0, the AGC command is determined to be invalid. If the wind power station and energy storage power station are in the centralized control mode, and the photovoltaic power station is in the direct grid dispatch mode, then the step of allocating the station execution command to the corresponding power station in the centralized control mode includes: calculating the command deviation between the actual active power generated at the current grid connection point and the AGC command; if the command deviation is greater than the preset allowable deviation dead zone for the station, then the station execution command is allocated to the wind power station according to the following formula. And allocate site execution instructions to the energy storage power station according to the following formula. In the formula, This indicates the portion of the energy storage power station allocated from the site according to the instructions executed. This indicates the portion of the wind power plant that is allocated from the site according to the instructions. This indicates that the station is executing instructions, and , This refers to the AGC instruction. This indicates the actual active power generated by the photovoltaic power station. This indicates the maximum active power that the wind power station can generate. This indicates the minimum active power that a wind power station can generate. This indicates the maximum charging power of the energy storage power station. This indicates the maximum discharge capacity of the energy storage power station; If the wind power station is in centralized control mode and the photovoltaic power station and energy storage power station are in direct grid dispatch mode, then the step of allocating the station execution command to the corresponding power station in centralized control mode includes: calculating the command deviation between the current active power generated at the grid connection point and the AGC command; if the command deviation is greater than the preset allowable dead zone for the station, then the station execution command is allocated to the wind power station according to the following formula. In the formula, This indicates the portion of the wind power plant that is allocated from the site according to the instructions. This indicates that the station is executing instructions, and , This refers to the AGC instruction. This indicates the actual active power generated by the photovoltaic power station. This indicates the actual active power generated by the energy storage power station. This indicates the maximum active power that the wind power station can generate. This indicates the minimum active power that a wind power station can generate; The second energy storage parameter setting module is used to set the upper and lower limits of the SOC of the energy storage power station to be put into operation as the third and fourth limits respectively if the primary frequency regulation control is entered, and to release the full capacity to participate in power output. The second instruction allocation module calculates the primary frequency regulation instruction increment, and after superimposing the primary frequency regulation instruction increment with the acquired AGC instruction, allocates it to the wind power station, the photovoltaic power station and the energy storage power station for execution; The third boundary is higher than the first boundary, and the fourth boundary is lower than the second boundary.

5. An electronic device, characterized in that, include: A memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, the processor executing the computer instructions to perform the method as described in any one of claims 1-3.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to perform the method as described in any one of claims 1-3.

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