A compressed air energy storage primary frequency modulation seamless switching control method and system

Abstract

The application relates to a compressed air energy storage primary frequency modulation seamless switching control method and system, wherein the control method comprises the following steps: receiving a frequency deviation signal and calculating an adjustment power required for primary frequency modulation; determining a frequency modulation level and respectively distributing adjustment instructions to a flywheel energy storage system and a compressed air energy storage system, so that the flywheel energy storage system firstly outputs or absorbs transient frequency modulation power; when the frequency modulation level reaches a compressed air energy storage starting condition, a fast warm-up starting instruction is sent to the compressed air energy storage system; after the compressed air energy storage system reaches a starting completion condition, the target frequency modulation power amount borne by the flywheel energy storage system is linearly reduced, and the target frequency modulation power amount borne by the compressed air energy storage system is linearly increased; after switching is completed, the flywheel energy storage system and the compressed air energy storage system are controlled to perform collaborative frequency modulation according to an over-frequency state or an under-frequency state corresponding to the frequency deviation signal, and the power distribution proportion of the two is adjusted according to an operation state.

Description

Technical Field

[0001] This application relates to the field of power system energy storage frequency regulation technology, specifically to a seamless switching control method and system for primary frequency regulation of compressed air energy storage. Background Technology

[0002] Primary frequency regulation requires energy storage systems to respond quickly and provide timely power output when grid frequency deviations occur, maintaining the frequency within the rated range. Compressed air energy storage for frequency regulation, as an energy-type storage solution, has advantages such as large capacity, long lifespan, and low cost, providing continuous frequency regulation power support. However, it suffers from slow start-up response, typically requiring several minutes, making it unable to cope with instantaneous frequency fluctuations in the grid and thus unable to participate in instantaneous primary frequency regulation tasks. Flywheel energy storage for frequency regulation has a fast response speed, quickly smoothing out instantaneous frequency fluctuations, but its energy capacity is limited, making it unable to undertake long-term continuous frequency regulation tasks. Related joint frequency regulation schemes do not include auxiliary start-up mechanisms to address the slow start-up problem of compressed air energy storage, and there is a significant power surge during the switching of dual energy storage systems, affecting grid stability. Furthermore, the lack of effective anti-surge and overspeed protection coordination logic results in insufficient system operational safety, failing to fully leverage the synergistic advantages of dual energy storage systems and making it difficult to meet the high-efficiency, fast, and safe requirements of primary grid frequency regulation. Summary of the Invention

[0003] The first aspect of this application provides a seamless switching control method for primary frequency regulation of compressed air energy storage, which can improve the response speed and continuous support capability of the primary frequency regulation process.

[0004] The compressed air energy storage primary frequency regulation seamless switching control method provided in the first aspect of this application includes: receiving the frequency deviation signal uploaded by the power grid interface layer in real time, and calculating the regulation power required for primary frequency regulation based on the frequency deviation signal; The frequency modulation level is determined based on the amplitude of the frequency deviation signal. Adjustment commands are assigned to the flywheel energy storage system and the compressed air energy storage system respectively, so that the flywheel energy storage system outputs or absorbs instantaneous frequency modulation power first. When the frequency modulation level reaches the start-up conditions of the compressed air energy storage system, a rapid warm-up start-up command is sent to the compressed air energy storage system, so that the compressed air energy storage system enters the pre-operation state. After the compressed air energy storage system reaches the start-up completion condition, the target frequency regulation power undertaken by the flywheel energy storage system is linearly reduced, and the target frequency regulation power undertaken by the compressed air energy storage system is linearly increased, so that the total frequency regulation power formed by the superposition of the flywheel energy storage system and the compressed air energy storage system remains stable. After the switching is completed, the flywheel energy storage system and the compressed air energy storage system are controlled to perform coordinated frequency regulation according to the over-frequency or under-frequency state corresponding to the frequency deviation signal, and the power distribution ratio between the flywheel energy storage system and the compressed air energy storage system is adjusted according to their operating status during the frequency regulation process.

[0005] In one alternative embodiment, the frequency deviation signal includes a frequency deviation Δf, which is the difference between the actual frequency of the power grid and the rated frequency. When |Δf|≤0.05Hz, the frequency modulation level is determined as a first-level deviation, the flywheel energy storage system is controlled to participate in power regulation, and the compressed air energy storage system is kept off. When 0.05Hz < |Δf| ≤ 0.2Hz, the frequency modulation level is determined to be a second-level deviation, the flywheel energy storage system is controlled to perform full-power instantaneous adjustment, and the compressed air energy storage system is controlled to start, so that the compressed air energy storage system gradually increases the adjustment power; When |Δf|>0.2Hz, the frequency modulation level is determined to be a level three deviation, the flywheel energy storage system is controlled to perform full-power instantaneous adjustment, and the compressed air energy storage system is controlled to start up quickly, so that the compressed air energy storage system can increase the adjustment power or participate in continuous power adjustment according to the adjustment power after the adjustment conditions are met.

[0006] In one alternative approach, controlling the flywheel energy storage system and the compressed air energy storage system to perform coordinated frequency regulation includes: During the overclocking state, the flywheel energy storage system is controlled to preferentially absorb instantaneous redundant power, and the compressed air energy storage system is controlled to enter the energy storage mode to absorb the remaining redundant power. In the underfrequency state, the flywheel energy storage system is controlled to release instantaneous power first, and the compressed air energy storage system is controlled to enter the energy release mode to continuously output frequency-modulated power.

[0007] In one optional scheme, the start-up completion conditions include: the unit temperature of the compressed air energy storage system reaches more than 85% of the rated temperature, and the gas storage pressure of the compressed air energy storage system reaches more than 80% of the rated pressure.

[0008] In one alternative scheme, after the compressed air energy storage system reaches the start-up completion condition, a seamless power switching control is initiated, wherein the transition time of the seamless power switching control is 5~15s. During the transition time, the target frequency regulation power of the flywheel energy storage system and the target frequency regulation power of the compressed air energy storage system are determined according to the regulation power, so that the target frequency regulation power undertaken by the flywheel energy storage system decreases linearly with the transition time, and the target frequency regulation power undertaken by the compressed air energy storage system increases linearly with the transition time, so that the total frequency regulation power formed by the superposition of the flywheel energy storage system and the compressed air energy storage system matches the regulation power.

[0009] In one alternative approach, the frequency modulation process also includes: When the compressed air energy storage system experiences a surge warning, the loading rate of the compressed air energy storage system should be reduced. When the flywheel speed of the flywheel energy storage system exceeds 110% of the rated speed, the output of the flywheel energy storage system is cut off. When either the flywheel energy storage system or the compressed air energy storage system fails, the other system is controlled to assume all frequency regulation power, and the coordinated regulation mode of the flywheel energy storage system and the compressed air energy storage system is restored after the fault is cleared.

[0010] In one alternative approach, during frequency regulation, the flywheel speed, the compressed air energy storage system's storage pressure, and the power output parameters are monitored in real time, and the power distribution ratio between the flywheel energy storage system and the compressed air energy storage system is adjusted based on the flywheel speed, the storage pressure, and the power output parameters.

[0011] This compressed air energy storage primary frequency regulation seamless switching control method acquires the grid frequency deviation signal in real time and determines the frequency regulation level based on the frequency deviation amplitude. This allows the flywheel energy storage system to prioritize outputting or absorbing instantaneous frequency regulation power in the initial stage of frequency fluctuation, while simultaneously triggering the rapid warm-up and start-up of the compressed air energy storage system. By utilizing the fast response speed of flywheel energy storage, it compensates for the insufficient start-up speed of compressed air energy storage, enabling the compressed air energy storage system to participate in continuous frequency regulation in a timely manner.

[0012] After the compressed air energy storage system reaches the start-up conditions, the frequency regulation power undertaken by the flywheel energy storage system is gradually reduced while that undertaken by the compressed air energy storage system is gradually increased, so as to achieve a smooth power continuity between the two energy storage systems and reduce power fluctuations during the switching process. At the same time, the power distribution of the two energy storage systems is dynamically adjusted according to the over-frequency or under-frequency state of the power grid, so that the flywheel energy storage system undertakes the task of rapid response and the compressed air energy storage system undertakes the task of continuous regulation, thereby improving the response speed and continuous support capability of the primary frequency regulation process.

[0013] The second aspect of this application provides a seamless switching system for primary frequency regulation of compressed air energy storage, used to execute the seamless switching control method for primary frequency regulation of compressed air energy storage provided in the first aspect. The system includes a grid interface layer, a control center, a flywheel energy storage system, a compressed air energy storage system, a booster station electrical monitoring system, and a communication module. The power grid interface layer is connected to the control center through the communication module and is used to upload frequency deviation signals to the control center. The control center includes a primary frequency modulation control module and a collaborative scheduling module. The primary frequency modulation control module is used to calculate the adjustment power required for primary frequency modulation based on the frequency deviation signal. The collaborative scheduling module is used to send adjustment commands to the flywheel energy storage system and the compressed air energy storage system through the communication module based on the amplitude of the frequency deviation signal. The flywheel energy storage system is used to output or absorb instantaneous frequency modulation power according to the adjustment command; The compressed air energy storage system is used to enter the frequency modulation state according to the adjustment command, and enter the pre-operation state according to the rapid warm-up start command sent by the collaborative scheduling module. After the start-up completion conditions are met, it participates in continuous frequency modulation. The collaborative scheduling module is also used to send power switching commands to the flywheel energy storage system and the compressed air energy storage system after the compressed air energy storage system reaches the start-up completion conditions, so as to control the flywheel energy storage system and the compressed air energy storage system to perform power switching. The booster station electrical monitoring system is used to monitor the operating status of the flywheel energy storage system and the compressed air energy storage system; the communication module is used to realize signal transmission.

[0014] This compressed air energy storage system, designed for seamless switching during primary frequency regulation, integrates a grid interface layer, a control center, a flywheel energy storage system, a compressed air energy storage system, a booster station electrical monitoring system, and a communication module. This enables the system to acquire grid frequency information, distribute regulation commands, and facilitate information exchange between the two energy storage systems. The control center can coordinate the operation of both the flywheel and compressed air energy storage systems based on grid frequency changes. The flywheel energy storage system rapidly executes instantaneous frequency regulation commands, while the compressed air energy storage system provides continuous frequency regulation support after startup. This synergistic configuration of the two energy storage methods enhances the system's responsiveness and continuous regulation capabilities during primary frequency regulation. Furthermore, the booster station electrical monitoring system monitors the operating status of the energy storage system, improving overall system reliability.

[0015] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0016] Figure 1This is a schematic diagram of the control logic in one embodiment of the primary frequency modulation seamless switching control method.

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0018] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0019] It should be understood that the described embodiments are merely some embodiments of this application, and not all embodiments. All other technical solutions obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0020] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0021] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0022] like Figure 1 As shown, the first aspect of this application provides a seamless switching control method for primary frequency regulation of compressed air energy storage. The seamless switching control method for primary frequency regulation of compressed air energy storage includes the following steps: receiving the frequency deviation signal uploaded by the grid interface layer in real time, and calculating the adjustment power required for primary frequency regulation based on the frequency deviation signal; The frequency modulation level is determined based on the amplitude of the frequency deviation signal. Adjustment commands are assigned to the flywheel energy storage system and the compressed air energy storage system respectively, so that the flywheel energy storage system outputs or absorbs instantaneous frequency modulation power first. When the frequency modulation level reaches the start-up conditions of the compressed air energy storage system, a rapid warm-up start-up command is sent to the compressed air energy storage system, so that the compressed air energy storage system enters the pre-operation state. After the compressed air energy storage system reaches the start-up completion condition, the target frequency regulation power undertaken by the control flywheel energy storage system is linearly reduced, and the target frequency regulation power undertaken by the control compressed air energy storage system is linearly increased, so that the total frequency regulation power formed by the superposition of the flywheel energy storage system and the compressed air energy storage system remains stable. After the switch is completed, the flywheel energy storage system and the compressed air energy storage system are controlled to perform coordinated frequency regulation according to the over-frequency or under-frequency state corresponding to the frequency deviation signal. During the frequency regulation process, the power distribution ratio between the flywheel energy storage system and the compressed air energy storage system is adjusted according to their operating status.

[0023] The frequency deviation signal characterizes the degree of deviation of the current grid frequency from the rated frequency. The control center determines the required adjustment direction and power based on this signal. When the grid frequency changes, the flywheel energy storage system can quickly adjust its output or absorbed power to initially compensate for the frequency change, utilizing its fast response capability. Simultaneously, the compressed air energy storage system enters a pre-operational preparation state based on the start-up command, enabling it to take over the continuous adjustment task from the flywheel energy storage system after startup. Through this control process, both energy storage systems leverage their respective advantages of rapid response and continuous support.

[0024] Specifically, a flywheel energy storage system may include a flywheel body, a motor connected to the flywheel body, and a power conversion device for controlling power exchange. A compressed air energy storage system may include an energy conversion device such as a compressor, an air storage device, and an expander. The control center sends control commands to both the flywheel energy storage system and the compressed air energy storage system via a communication module, enabling the two types of energy storage devices to operate collaboratively according to a preset adjustment logic.

[0025] The seamless switching control method for primary frequency regulation of compressed air energy storage in this embodiment acquires the grid frequency deviation signal in real time and determines the frequency regulation level according to the amplitude of the frequency deviation. This allows the flywheel energy storage system to prioritize outputting or absorbing instantaneous frequency regulation power in the initial stage of frequency fluctuation, while simultaneously triggering the rapid warm-up and start-up of the compressed air energy storage system. This utilizes the fast response speed of flywheel energy storage to compensate for the insufficient start-up speed of compressed air energy storage, enabling the compressed air energy storage system to participate in continuous frequency regulation in a timely manner.

[0026] After the compressed air energy storage system reaches the start-up conditions, the frequency regulation power undertaken by the flywheel energy storage system is gradually reduced while that undertaken by the compressed air energy storage system is gradually increased, so as to achieve a smooth power continuity between the two energy storage systems and reduce power fluctuations during the switching process. At the same time, the power distribution of the two energy storage systems is dynamically adjusted according to the over-frequency or under-frequency state of the power grid, so that the flywheel energy storage system undertakes the task of rapid response and the compressed air energy storage system undertakes the task of continuous regulation, thereby improving the response speed and continuous support capability of the primary frequency regulation process.

[0027] In one specific embodiment, the frequency deviation signal includes a frequency deviation Δf, which is the difference between the actual frequency of the power grid and the rated frequency. When |Δf|≤0.05Hz, the frequency modulation level is set to Level 1 deviation, the flywheel energy storage system is controlled to participate in power regulation, and the compressed air energy storage system is kept off. When 0.05Hz < |Δf| ≤ 0.2Hz, the frequency modulation level is determined to be a second-level deviation, the flywheel energy storage system is controlled to perform full-power instantaneous adjustment, and the compressed air energy storage system is controlled to start, so that the compressed air energy storage system gradually increases the adjustment power; When |Δf|>0.2Hz, the frequency modulation level is set to level three deviation, the flywheel energy storage system is controlled to perform full-power instantaneous adjustment, and the compressed air energy storage system is controlled to start up quickly, so that the compressed air energy storage system can increase the adjustment power or participate in continuous power adjustment according to the adjustment power after the adjustment conditions are met.

[0028] This embodiment implements graded control of the frequency regulation process based on the amplitude of the frequency deviation, enabling the energy storage system to select corresponding response strategies according to different degrees of grid frequency disturbances. Specifically, when the frequency deviation is small, a flywheel energy storage system is used for rapid adjustment, avoiding frequent starts of the compressed air energy storage system; when the frequency deviation increases, the compressed air energy storage system is started in advance to establish operating parameters such as temperature and pressure, providing conditions for subsequent continuous frequency regulation.

[0029] Level 1 deviation mainly corresponds to small frequency fluctuations in the power grid, in which case a flywheel energy storage system can meet the rapid adjustment requirements. Level 2 and 3 deviations correspond to larger frequency disturbances, requiring greater continuous adjustment capabilities; therefore, a compressed air energy storage system is activated to participate in frequency regulation. This hierarchical control method reduces unnecessary start-ups and shutdowns of energy storage devices while ensuring response speed, thus improving system operating efficiency. It should be noted that the threshold values ​​for frequency deviation levels can be adjusted according to power grid operating requirements and the rated parameters of the energy storage system to adapt to the primary frequency regulation needs of different application scenarios.

[0030] In one specific embodiment, controlling the flywheel energy storage system and the compressed air energy storage system to perform coordinated frequency regulation includes: In overclocking mode, the flywheel energy storage system is controlled to absorb instantaneous redundant power first, and the compressed air energy storage system is controlled to enter the energy storage mode to absorb the remaining redundant power. In the underfrequency state, the flywheel energy storage system is controlled to release instantaneous power first, and the compressed air energy storage system is controlled to enter the energy release mode to continuously output frequency-modulated power.

[0031] The operation of the energy storage system is controlled according to the direction of grid frequency changes, enabling it to simultaneously meet regulation needs under both frequency increases and decreases. When the grid is in an overfrequency state, the flywheel energy storage system prioritizes absorbing instantaneous redundant power, quickly reducing frequency deviation; the compressed air energy storage system then enters energy storage mode to continuously absorb the remaining power. When the grid is in an underfrequency state, the flywheel energy storage system prioritizes releasing power to quickly compensate for the grid power deficit; the compressed air energy storage system then enters energy release mode to provide continuous power support. Through this coordinated frequency regulation method, the flywheel energy storage system primarily undertakes the task of rapid power response, while the compressed air energy storage system primarily undertakes the task of continuous power regulation. This avoids the frequency regulation effect being affected by the response speed or energy storage capacity limitations of a single energy storage method, improving the overall regulation capability of the dual energy storage system.

[0032] In one specific embodiment, the start-up completion conditions include: the unit temperature of the compressed air energy storage system reaching at least 85% of its rated temperature, and the gas storage pressure of the compressed air energy storage system reaching at least 80% of its rated pressure. The unit temperature and gas storage pressure are used together to determine whether the compressed air energy storage system has the capability to participate in continuous frequency regulation. The unit temperature reflects the operating status of the compressed air energy storage system's thermodynamic conversion process, while the gas storage pressure reflects the system's ability to output or absorb power. When the unit temperature and gas storage pressure meet the corresponding conditions, it indicates that the compressed air energy storage system has the operational basis to participate in power regulation.

[0033] It should be noted that the start-up completion conditions of a compressed air energy storage system can be adjusted based on the equipment structure, rated operating parameters, and actual operating environment. By setting start-up completion judgment conditions, the compressed air energy storage system can be prevented from directly participating in frequency regulation before reaching a stable operating state, thereby ensuring the stability of the power switching process.

[0034] Furthermore, after the compressed air energy storage system meets the start-up completion conditions, seamless power switching control is implemented, with a transition time of 5-15 seconds. During this transition time, the target frequency regulation power of the flywheel energy storage system and the compressed air energy storage system are determined separately according to the regulation power. This ensures that the target frequency regulation power borne by the flywheel energy storage system decreases linearly with the transition time, while the target frequency regulation power borne by the compressed air energy storage system increases linearly with the transition time, so that the total frequency regulation power formed by the superposition of the flywheel energy storage system and the compressed air energy storage system matches the regulation power.

[0035] This embodiment achieves a smooth transition between different response stages of the flywheel energy storage system and the compressed air energy storage system by setting a seamless power switching control process. Before the compressed air energy storage system reaches the start-up completion condition, the flywheel energy storage system undertakes the main frequency regulation task; once the compressed air energy storage system has regulation capability, the frequency regulation power undertaken by the flywheel energy storage system is reduced while the frequency regulation power undertaken by the compressed air energy storage system is increased, so that the power output of the two energy storage systems is continuously connected.

[0036] Specifically, the control center can generate a corresponding target power curve based on the current adjustment power, and adjust the target frequency regulation power of the flywheel energy storage system and the compressed air energy storage system according to the preset transition time, so that the change trend of the output power of the two systems matches each other, thereby avoiding power sudden changes caused by the sudden withdrawal of one energy storage system or the sudden activation of another energy storage system.

[0037] In one specific embodiment, the frequency regulation process further includes: reducing the loading rate of the compressed air energy storage system when a surge warning occurs; cutting off the output of the flywheel energy storage system when the flywheel speed of the flywheel energy storage system exceeds 110% of the rated speed; and controlling the other to bear all the frequency regulation power when either the flywheel energy storage system or the compressed air energy storage system fails, and restoring the coordinated regulation mode of the flywheel energy storage system and the compressed air energy storage system after the fault is cleared.

[0038] This embodiment sets corresponding protection strategies based on the operating characteristics of the compressed air energy storage system and the flywheel energy storage system, enabling the dual energy storage system to maintain safe operation during primary frequency regulation. Specifically, the compressed air energy storage system is affected by the operating status of the compressor and expander during operation. When surge risk occurs, reducing the loading rate can minimize the amplitude of changes in equipment operating status and reduce the risk of abnormal operation.

[0039] The flywheel energy storage system determines its operating status by detecting the flywheel speed. When the flywheel speed exceeds a preset safe range, it cuts off the output to prevent the flywheel from continuing to accelerate, thus protecting the safe operation of the flywheel energy storage system. Simultaneously, if any energy storage system fails, the other energy storage system temporarily takes over the frequency regulation task, preventing a single device malfunction from causing complete failure of the frequency regulation function. After the fault is resolved, the system re-enters the dual-energy storage collaborative regulation mode, improving the system's operational reliability.

[0040] In one specific embodiment, during frequency modulation, the flywheel speed, the gas storage pressure of the compressed air energy storage system, and the power output parameters are monitored in real time, and the power distribution ratio between the flywheel energy storage system and the compressed air energy storage system is adjusted according to the flywheel speed, gas storage pressure, and power output parameters.

[0041] By acquiring real-time operating status parameters of the dual energy storage system, the control center can dynamically adjust the power distribution ratio based on the current status of the energy storage devices. Specifically, flywheel speed reflects the remaining adjustable capacity of the flywheel energy storage system, gas pressure reflects the energy storage status and continuous output capacity of the compressed air energy storage system, and power output parameters reflect the current frequency regulation execution status. Adjusting the power distribution ratio between the two energy storage systems based on these operating parameters avoids a single energy storage system bearing a large regulation load for extended periods. This allows the flywheel and compressed air energy storage systems to work collaboratively according to their respective operating characteristics, improving the stability and regulation capability of the dual energy storage system during operation.

[0042] The second aspect of this application provides a compressed air energy storage primary frequency regulation seamless switching system for executing the compressed air energy storage primary frequency regulation seamless switching control method in the first aspect embodiment. The system includes a grid interface layer, a control center, a flywheel energy storage system, a compressed air energy storage system, a booster station electrical monitoring system, and a communication module. The power grid interface layer communicates with the control center through a communication module and is used to upload frequency deviation signals to the control center. The control center includes a primary frequency control module and a collaborative scheduling module. The primary frequency control module is used to calculate the adjustment power required for primary frequency regulation based on the frequency deviation signal. The collaborative scheduling module is used to send adjustment commands to the flywheel energy storage system and the compressed air energy storage system through the communication module based on the amplitude of the frequency deviation signal. Flywheel energy storage systems are used to output or absorb instantaneous frequency-modulated power according to regulation commands; The compressed air energy storage system is used to enter the frequency regulation state according to the adjustment command, and enter the pre-operation state according to the rapid warm-up start command sent by the collaborative scheduling module. After the start-up completion conditions are met, it participates in continuous frequency regulation. The collaborative scheduling module is also used to send power switching commands to the flywheel energy storage system and the compressed air energy storage system after the compressed air energy storage system reaches the start-up completion conditions, so as to control the flywheel energy storage system and the compressed air energy storage system to perform power switching. The substation electrical monitoring system is used to monitor the operating status of the flywheel energy storage system and the compressed air energy storage system; the communication module is used to realize signal transmission.

[0043] Specifically, the grid interface layer is used to acquire grid frequency change information and transmit it to the control center through the communication module. The control center calculates the adjustment power based on the received frequency deviation signal and sends corresponding control commands to the flywheel energy storage system and compressed air energy storage system through the collaborative scheduling module, so that different energy storage devices participate in primary frequency regulation according to the preset control logic.

[0044] The flywheel energy storage system and the compressed air energy storage system can be connected to the power grid through corresponding power conversion devices to achieve the conversion between electrical energy and stored energy. The control center interacts with each component through a communication module, forming a closed-loop control process for frequency detection, regulation calculation, power control, and operation monitoring. The substation electrical monitoring system can collect operating status information of the flywheel energy storage system and the compressed air energy storage system, such as power output status and equipment operating status, and feed this information back to the control center, enabling the control center to adjust the frequency regulation strategy according to the equipment status.

[0045] The compressed air energy storage primary frequency regulation seamless switching system in this embodiment achieves grid frequency information acquisition, regulation command allocation, and information interaction between the two energy storage systems by setting up a grid interface layer, a control center, a flywheel energy storage system, a compressed air energy storage system, a booster station electrical monitoring system, and a communication module. This enables the control center to coordinate the operation of the flywheel energy storage system and the compressed air energy storage system according to grid frequency changes. Specifically, the flywheel energy storage system is used to quickly execute instantaneous frequency regulation commands, while the compressed air energy storage system provides continuous frequency regulation support after startup. Through the coordinated configuration of the two energy storage methods, the response capability and continuous regulation capability of the energy storage system when participating in primary frequency regulation are improved. Simultaneously, the booster station electrical monitoring system monitors the operating status of the energy storage system, improving system reliability.

[0046] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for seamless switching control of primary frequency regulation in compressed air energy storage, characterized in that, include: The frequency deviation signal uploaded by the power grid interface layer is received in real time, and the adjustment power required for one frequency regulation is calculated based on the frequency deviation signal. The frequency modulation level is determined based on the amplitude of the frequency deviation signal. Adjustment commands are assigned to the flywheel energy storage system and the compressed air energy storage system respectively, so that the flywheel energy storage system outputs or absorbs instantaneous frequency modulation power first. When the frequency modulation level reaches the start-up conditions of the compressed air energy storage system, a rapid warm-up start-up command is sent to the compressed air energy storage system, so that the compressed air energy storage system enters the pre-operation state. After the compressed air energy storage system reaches the start-up completion condition, the target frequency regulation power undertaken by the flywheel energy storage system is linearly reduced, and the target frequency regulation power undertaken by the compressed air energy storage system is linearly increased, so that the total frequency regulation power formed by the superposition of the flywheel energy storage system and the compressed air energy storage system remains stable. After the switching is completed, the flywheel energy storage system and the compressed air energy storage system are controlled to perform coordinated frequency regulation according to the over-frequency or under-frequency state corresponding to the frequency deviation signal, and the power distribution ratio between the flywheel energy storage system and the compressed air energy storage system is adjusted according to their operating status during the frequency regulation process.

2. The compressed air energy storage primary frequency regulation seamless switching control method according to claim 1, characterized in that, The frequency deviation signal includes a frequency deviation Δf, which is the difference between the actual frequency of the power grid and the rated frequency. When |Δf|≤0.05Hz, the frequency modulation level is determined as a first-level deviation, the flywheel energy storage system is controlled to participate in power regulation, and the compressed air energy storage system is kept off. When 0.05Hz < |Δf| ≤ 0.2Hz, the frequency modulation level is determined to be a second-level deviation, the flywheel energy storage system is controlled to perform full-power instantaneous adjustment, and the compressed air energy storage system is controlled to start, so that the compressed air energy storage system gradually increases the adjustment power; When |Δf|>0.2Hz, the frequency modulation level is determined to be a level three deviation, the flywheel energy storage system is controlled to perform full-power instantaneous adjustment, and the compressed air energy storage system is controlled to start up quickly, so that the compressed air energy storage system can increase the adjustment power or participate in continuous power adjustment according to the adjustment power after the adjustment conditions are met.

3. The compressed air energy storage primary frequency regulation seamless switching control method according to claim 1, characterized in that, The coordinated frequency regulation of the flywheel energy storage system and the compressed air energy storage system includes: During the overclocking state, the flywheel energy storage system is controlled to preferentially absorb instantaneous redundant power, and the compressed air energy storage system is controlled to enter the energy storage mode to absorb the remaining redundant power. In the underfrequency state, the flywheel energy storage system is controlled to release instantaneous power first, and the compressed air energy storage system is controlled to enter the energy release mode to continuously output frequency-modulated power.

4. The compressed air energy storage primary frequency regulation seamless switching control method according to any one of claims 1-3, characterized in that, The start-up completion conditions include: the unit temperature of the compressed air energy storage system reaches more than 85% of the rated temperature, and the gas storage pressure of the compressed air energy storage system reaches more than 80% of the rated pressure.

5. The compressed air energy storage primary frequency regulation seamless switching control method according to claim 4, characterized in that, After the compressed air energy storage system reaches the start-up completion condition, the start-up power seamless switching control is implemented, and the transition time of the power seamless switching control is 5~15s; During the transition time, the target frequency regulation power of the flywheel energy storage system and the target frequency regulation power of the compressed air energy storage system are determined according to the regulation power, so that the target frequency regulation power undertaken by the flywheel energy storage system decreases linearly with the transition time, and the target frequency regulation power undertaken by the compressed air energy storage system increases linearly with the transition time, so that the total frequency regulation power formed by the superposition of the flywheel energy storage system and the compressed air energy storage system matches the regulation power.

6. The compressed air energy storage primary frequency regulation seamless switching control method according to any one of claims 1-3 or 5, characterized in that, The frequency modulation process also includes: When the compressed air energy storage system experiences a surge warning, the loading rate of the compressed air energy storage system should be reduced. When the flywheel speed of the flywheel energy storage system exceeds 110% of the rated speed, the output of the flywheel energy storage system is cut off. When either the flywheel energy storage system or the compressed air energy storage system fails, the other system is controlled to assume all frequency regulation power, and the coordinated regulation mode of the flywheel energy storage system and the compressed air energy storage system is restored after the fault is cleared.

7. The compressed air energy storage primary frequency regulation seamless switching control method according to any one of claims 1-3 or 5, characterized in that, During frequency regulation, the flywheel speed, compressed air energy storage pressure, and power output parameters of the compressed air energy storage system are monitored in real time, and the power distribution ratio between the flywheel energy storage system and the compressed air energy storage system is adjusted according to the flywheel speed, the compressed air pressure, and the power output parameters.

8. A compressed air energy storage primary frequency regulation seamless switching system, used to execute the compressed air energy storage primary frequency regulation seamless switching control method according to any one of claims 1-7, characterized in that, It includes the grid interface layer, control center, flywheel energy storage system, compressed air energy storage system, substation electrical monitoring system, and communication module; The power grid interface layer is connected to the control center through the communication module and is used to upload frequency deviation signals to the control center. The control center includes a primary frequency modulation control module and a collaborative scheduling module. The primary frequency modulation control module is used to calculate the adjustment power required for primary frequency modulation based on the frequency deviation signal. The collaborative scheduling module is used to send adjustment commands to the flywheel energy storage system and the compressed air energy storage system through the communication module based on the amplitude of the frequency deviation signal. The flywheel energy storage system is used to output or absorb instantaneous frequency modulation power according to the adjustment command; The compressed air energy storage system is used to enter the frequency regulation state according to the adjustment command, and enter the pre-operation state according to the rapid warm-up start command sent by the collaborative scheduling module, and participate in continuous frequency regulation after the start-up completion conditions are met; The collaborative scheduling module is also used to send a power switching command to the flywheel energy storage system and the compressed air energy storage system after the compressed air energy storage system reaches the start-up completion condition, so as to control the flywheel energy storage system and the compressed air energy storage system to perform power switching. The booster station electrical monitoring system is used to monitor the operating status of the flywheel energy storage system and the compressed air energy storage system; the communication module is used to realize signal transmission.

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