A non-uniform salt cavern energy storage multi-branch air flow equalization regulation system and method

Abstract

The application belongs to the technical field of airflow regulation, and discloses a multi-branch airflow equalization regulation system and method for non-uniform salt cavern energy storage, which comprises a mother pipe, the mother pipe is connected with an energy storage unit, an energy release unit and a plurality of salt cavern units, the energy storage unit injects gas into the salt cavern units through the mother pipe, the salt cavern units generate electricity for the energy release unit through the mother pipe, the salt cavern units are electrically connected with a control unit, and are used for feeding the working condition parameters of the salt cavern units to the control unit, and adjusting valves are electrically connected with the control unit, receive the valve opening degree adjustment instructions issued by the control unit, the control unit acquires the working condition parameters of the salt cavern units in real time, adjusts the opening degrees of the adjusting valves of the branches according to the feedback signals, avoids the phenomenon that the near-end salt cavern reaches the upper limit of pressure too early while the far-end salt cavern is not full, dynamically adjusts the opening degrees of the adjusting valves of the branches, supplies gas to the salt cavern units as needed, and avoids uneven flow distribution caused by differences in along-path resistance.

Description

Technical Field

[0001] This invention belongs to the field of airflow control technology and relates to a multi-branch airflow equalization control system and method for non-uniform salt cavern energy storage. Background Technology

[0002] In compressed air energy storage systems, multiple underground salt caverns are often used as storage spaces. The varying lengths of the main pipes connecting different salt caverns to the surface compressor / expander units create a non-uniformly distributed cluster of salt caverns. During the energy storage (injection) phase, the compressor unit simultaneously injects air into each salt cavern through the main pipe. Salt caverns closer to the source with lower pipe resistance experience faster air intake and pressure rise, while those farther away with higher pipe resistance experience slower air intake and delayed pressure rise. Nearby salt caverns are more likely to reach their pressure limit first and be forced to stop injection, while farther salt caverns remain unfilled, reducing the effective energy storage capacity.

[0003] During the energy release (power generation) phase, each salt cavern simultaneously supplies gas to the turbine unit. Salt cavern units located far apart experience greater pressure loss at the turbine inlet due to higher frictional resistance, leading to uneven flow distribution across branches. Conversely, salt cavern units near the inlet may exhaust gas too quickly, causing a sudden drop in wellhead pressure and potentially inducing geological instability risks in the salt caverns.

[0004] Existing multi-branch airflow control methods for compressed air energy storage systems do not consider the differences in branch pipe resistance caused by the non-uniform distribution of salt caverns, lack targeted equalization control strategies, and cannot solve problems such as uneven pressure rise during the energy storage stage and uneven flow distribution and pressure fluctuations during the energy release stage. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a multi-branch airflow equalization control system and method for non-uniform salt cavern energy storage.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a multi-branch airflow equalization control system for non-uniform salt cavern energy storage, comprising: a main pipe, which is connected to an energy storage unit, an energy release unit, and several salt cavern units respectively; the energy storage unit injects gas into the several salt cavern units through the main pipe; the several salt cavern units generate electricity to the energy release unit through the main pipe; the several salt cavern units are electrically connected to a control unit for feeding back the operating parameters of each salt cavern unit to the control unit; each salt cavern unit includes a regulating valve, and several regulating valves are electrically connected to the control unit to receive valve opening adjustment commands issued by the control unit.

[0007] Furthermore, the energy storage unit includes a compressor system, a check valve, and a control valve connected in sequence, with one end of the control valve connected to the main pipe and the other end connected to the check valve; the energy release unit includes an intake control valve and an expander connected in sequence, with one end of the intake control valve connected to the main pipe and the other end connected to the expander.

[0008] Furthermore, the salt cavern unit also includes a bidirectional flow meter and an electric valve connected in sequence. One end of the bidirectional flow meter is connected to the main pipe, and the other end is connected to the electric valve. A first pressure measuring point is provided between the electric valve and the regulating valve, and a second pressure measuring point and a temperature measuring point are provided between the regulating valve and the salt cavern.

[0009] Furthermore, the first pressure measuring point is set on the inlet side of the regulating valve to detect the pressure before the valve; the second pressure measuring point is set on the outlet side of the regulating valve to detect the pressure after the valve. The control unit adjusts the opening of the regulating valve according to the values ​​of the first pressure measuring point and the temperature measuring point.

[0010] Furthermore, the regulating valve is an electrically operated regulating valve.

[0011] This invention also provides a multi-branch airflow equalization control method for non-uniform salt cavern energy storage. Based on the aforementioned multi-branch airflow equalization control system for non-uniform salt cavern energy storage, the method includes the following steps: the branch connected to the control unit and the longest salt cavern unit in the main pipe among several salt cavern units is the main control reference branch, and a target total resistance reference value is obtained based on the main control reference branch; the control unit calculates the theoretical artificial pressure drop value required for each subordinate branch based on the target total resistance reference value; the theoretical artificial pressure drop value required for each subordinate branch is converted into a theoretical valve opening command, and the gas temperature after the electric regulating valve of the subordinate branch is monitored. If the gas temperature is less than a preset safe temperature threshold, the opening of the electric regulating valve of that branch is increased, and the actual opening command after temperature correction is obtained; when the control unit adjusts the regulating valve according to the actual opening command, it simultaneously monitors the pressure change rate inside each salt cavern. If the pressure change rate is greater than or equal to the geological allowable pressure change rate threshold, the adjustment rate of the regulating valve is limited, and a flow regulation command is obtained; the control unit outputs control commands from longest to shortest based on the flow regulation command and the length of the main pipe and the control unit.

[0012] Furthermore, the control unit outputs control commands based on the flow regulation command and the length of the main pipe and the control unit, including: first opening the regulating valve with the longest length of the main pipe and the control unit, and after a first preset delay, opening the regulating valve of the branch with the second longest length of the main pipe and the control unit, and slowly loading to the target opening degree required by the flow regulation command according to the ramp function.

[0013] Furthermore, the pressure change rate is less than the geologically permissible pressure change rate threshold, and is adjusted according to the actual opening command after temperature correction.

[0014] Furthermore, the gas temperature is greater than or equal to a preset safe temperature threshold to maintain the theoretical valve opening command.

[0015] Furthermore, when the gas temperature is less than -10°C, the control unit increases the opening of the branch electric regulating valve at a rate of 5% per second until the gas temperature rises back to ≥-10°C.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a multi-branch airflow balancing control system for non-uniform salt cavern energy storage. The control unit acquires the operating parameters of each salt cavern unit in real time and independently adjusts the opening of the regulating valves of each branch according to the feedback signals. This avoids the phenomenon that the near-end salt cavern reaches the pressure limit too early while the far-end salt cavern is not yet full. During the power generation process, the control unit dynamically adjusts the opening of the regulating valves of each branch according to the pressure, temperature and flow parameters fed back by each salt cavern unit, so that the salt cavern unit supplies gas on demand and avoids uneven flow distribution caused by differences in friction resistance.

[0017] The branch connected to the longest salt cavern unit in the main pipe is set as the main control reference branch, and the target total resistance reference value is obtained. The control unit calculates the theoretical artificial pressure drop value required for each subordinate branch based on the target total resistance reference value, so that branches with different distances and pipe resistances can achieve resistance matching at the control level, eliminating uneven gas injection or exhaust caused by differences in physical pipelines. During the operation of the regulating valve, the pressure change rate inside each salt cavern is monitored simultaneously. Once the change rate exceeds the geological allowable threshold, the valve adjustment rate is limited to prevent sudden pressure changes from impacting or collapsing the salt cavern cavity. The control unit outputs control commands based on the flow regulation command and in combination with the length sequence of each branch and the main pipe, optimizing the action sequence of branches with different distances. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of a multi-branch airflow equalization and control system for non-uniform salt cavern energy storage according to the present invention. Figure 2 This is a flowchart of a multi-branch airflow equalization control method for non-uniform salt cavern energy storage according to the present invention. Figure 3 This is a pressure-distance compensation control diagram for the salt cavern unit in an embodiment of the present invention.

[0019] Figure label: 1-Compressor system; 2-Check valve; 3-Control valve; 4-Expander; 5-Inlet control valve; 6-Temperature measuring point; 7-Second pressure measuring point; 8-Regulating valve; 9-First pressure measuring point; 10-Electric valve; 11-Two-way flow meter; 12-Main pipe. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] Example 1 This invention discloses a multi-branch airflow equalization control system for non-uniform salt cavern energy storage, comprising: a main pipe 12, which is connected to an energy storage unit, an energy release unit, and several salt cavern units. The energy storage unit injects gas into the several salt cavern units through the main pipe 12, and the several salt cavern units generate electricity to the energy release unit through the main pipe 12. Each of the several salt cavern units is electrically connected to a control unit, used to feed back the operating parameters of each salt cavern unit to the control unit and receive valve opening adjustment commands issued by the control unit, such as... Figure 1 As shown.

[0022] The main pipe 12 connects the energy storage unit, the energy release unit, and each salt cavern unit. For example... Figure 1 As shown, the leftmost part connected to the main pipe 12 is the energy storage unit, which converts external electrical energy into the potential energy of high-pressure air. The energy storage unit includes a compressor system 1, a check valve 2, and a control valve 3 connected in sequence. The compressor system 1 converts low-pressure air into high-pressure air. The check valve 2 is connected between the compressor system 1 and the control valve 3 to prevent high-pressure gas in the main pipe 12 from flowing back to the compressor system 1, ensuring that high-pressure air can only be delivered from the compressor system 1 to the main pipe 12. One end of the control valve 3 is connected to the main pipe 12, and the other end is connected to the check valve 2. It controls the flow of fluid between the energy storage unit and the main pipe 12. During the gas injection phase, it opens to deliver high-pressure air to the main pipe 12, and during the energy release phase, it closes to cut off the connection between the energy storage unit and the main pipe 12, preventing high-pressure gas from flowing back.

[0023] The energy release unit converts the stored high-pressure air potential energy into electrical energy. The energy release unit includes an intake control valve 5 and an expander 4 connected in sequence. One end of the intake control valve 5 is connected to the main pipe 12, and the other end is connected to the expander 4. It controls the delivery of high-pressure gas from the main pipe 12 to the expander 4, opening during the energy release phase and closing during the gas injection phase to prevent high-pressure air from entering the expander 4. The expander 4 converts the potential energy of the high-pressure gas delivered from the main pipe 12 into mechanical energy, driving a generator to generate electricity.

[0024] Several salt cavern units are electrically connected to the control unit, feeding back the operating parameters of each salt cavern unit to the control unit. The control unit receives the feedback parameters and issues various adjustment commands. Each salt cavern unit includes a bidirectional flow meter 11, an electric valve 10, and a regulating valve 8. One end of the bidirectional flow meter 11 is connected to the main pipe 12, and the other end is connected to the electric valve 10, which detects the bidirectional flow of gas in the corresponding branch in real time, so that the control unit can judge the airflow status of each branch, whether it is the gas injection flow in the energy storage stage or the energy release flow in the energy release stage. The electric valve 10 is connected between the bidirectional flow meter 11 and the regulating valve 8, controlling the fluid flow between the salt cavern unit and the main pipe 12. It is opened during the gas injection stage to inject high-pressure air into the salt cavern, and opened during the energy release stage to deliver high-pressure gas to the main pipe 12.

[0025] A first pressure measuring point 9 is provided between the electric valve 10 and the regulating valve 8. The first pressure measuring point 9 is located on the inlet side of the regulating valve 8 to detect the pressure before the regulating valve 8 and provide the control unit with the pressure data at the inlet of the regulating valve 8. This facilitates the control unit in calculating the pressure difference before and after the regulating valve 8. The regulating valve 8 is connected between the electric valve 10 and the salt cavern. Several regulating valves 8 are electrically connected to the control unit and receive valve opening adjustment commands issued by the control unit. By changing their own opening, they adjust the gas flow and pressure of the corresponding branch, thereby achieving balanced control of the airflow in multiple branches. The regulating valve 8 is an electric regulating valve that automatically adjusts the throttling degree according to the opening command issued by the control unit.

[0026] A second pressure measuring point 7 and a temperature measuring point 6 are installed between the regulating valve 8 and the salt cavern. The second pressure measuring point 7 is located on the outlet side of the regulating valve 8 and detects the downstream pressure of the regulating valve 8. This pressure, combined with the data from the first pressure measuring point 9, determines the throttling effect of the regulating valve 8. The temperature measuring point 6 detects the gas temperature at the outlet side of the regulating valve 8 and provides temperature data to the control unit to prevent excessively low gas temperatures caused by the throttling effect from leading to pipe icing or brittle fracture damage. The control unit adjusts the opening of the regulating valve 8 based on the values ​​from the first pressure measuring point 9 and the temperature measuring point 6.

[0027] The control unit first opens the control valve 3 of the energy storage unit and simultaneously closes the air intake control valve 5 of the energy release unit, entering the air injection state. Subsequently, the compressor system 1 starts, compressing the air and converting low-pressure air into high-pressure air. The high-pressure air then enters the main pipe 12 via the check valve 2 and control valve 3, completing the high-pressure air delivery. Based on the operating parameters of each salt cavern unit, the control unit sends an opening command to the electric valve 10 of each salt cavern unit and an initial opening command to the regulating valve 8, connecting each salt cavern unit to the main pipe 12. The high-pressure air in the main pipe 12 is injected into the salt cavern unit via the bidirectional flow meter 11, electric valve 10, and regulating valve 8, completing energy storage.

[0028] During the energy storage phase: The control unit monitors the injection flow rate of each branch in real time via a bidirectional flow meter 11, and monitors the pressure and gas temperature before and after the regulating valve 8 in real time via the first pressure measuring point 9, the second pressure measuring point 7, and the temperature measuring point 6. When the fluid resistance of a branch of a certain salt cavern unit is low due to the short branch between the main pipe 12 and the control unit, the control unit sends a command to the regulating valve 8 of that branch to reduce the opening, increasing the throttling resistance of the branch and making the injection flow rate of each branch more consistent, thus achieving synchronous injection. When the temperature measuring point 6 detects that the gas temperature after the valve is lower than the preset safety threshold, the control unit will increase the opening of the regulating valve 8 to reduce the throttling intensity and prevent pipeline icing or valve brittleness damage. At the same time, the control unit will also monitor the pressure change rate of each salt cavern unit to prevent pressure imbalance in the salt cavern units due to differences in injection rate.

[0029] Energy Release Phase: The control unit first opens the inlet control valve 5 of the energy release unit and simultaneously closes the control valve 3 of the energy storage unit. The control unit starts according to a preset reverse-sequence delay, prioritizing the opening of the electric valve 10 of the salt cavern unit with the longest branch and the greatest fluid resistance, then sequentially opening the electric valves 10 of other salt cavern units, and finally opening the electric valve 10 of the salt cavern unit with the shortest branch and the least fluid resistance. The high-pressure gas stored in the salt cavern unit flows out, passing through the regulating valve 8, electric valve 10, and bidirectional flow meter 11 into the main pipe 12. The main pipe 12 centrally delivers the high-pressure gas to the inlet control valve 5, which then enters the expander 4, driving the expander 4 to operate and converting the potential energy of the high-pressure gas into mechanical energy, thereby driving the generator to generate electricity. During the energy release phase, the control unit detects the energy release flow rate of each branch through the bidirectional flow meter 11, and detects the pressure and gas temperature before and after the regulating valve 8 through the first pressure measuring point 9, the second pressure measuring point 7, and the temperature measuring point 6, dynamically adjusting the state of each branch.

[0030] When a branch of a salt cavern unit experiences excessively high gas flow due to its short length, the control unit will issue a command to the regulating valve 8 of that branch to reduce its opening, increasing the throttling resistance of the branch and making the energy release flow of each branch more consistent. When the temperature measuring point 6 detects that the gas temperature after the valve is lower than the preset safety threshold, the control unit will forcibly adjust the opening of the regulating valve 8 to increase the valve opening and raise the gas temperature. It will also dynamically adjust the opening of the regulating valve 8 according to the pressure changes of each salt cavern unit to keep the pressure drop rate of each salt cavern unit consistent and prevent the near-end salt cavern unit from depleting high-pressure gas prematurely.

[0031] Example 2 This invention provides a method for equalizing and controlling the multi-branch airflow in non-uniform salt cavern energy storage, such as... Figure 2As shown, the process includes the following steps: The branch connecting the control unit to the longest salt cave unit among several salt cave units (the main pipe 12) is designated as the main control reference branch. A target total resistance reference value is obtained based on this main control reference branch. The control unit calculates the theoretical artificial pressure drop required for each subordinate branch based on the target total resistance reference value. The theoretical artificial pressure drop required for each subordinate branch is converted into a theoretical valve opening command, and the gas temperature after the electric regulating valve of the subordinate branch is monitored. If the gas temperature is less than a preset safe temperature threshold, the opening of the electric regulating valve of that branch is increased, and an actual opening command after temperature correction is obtained. When the control unit adjusts the regulating valve 8 according to the actual opening command, it simultaneously monitors the pressure change rate inside each salt cave. If the pressure change rate is greater than or equal to the geological allowable pressure change rate threshold, the adjustment rate of the regulating valve 8 is limited, and a flow regulation command is obtained. The control unit outputs a control command based on the flow regulation command and the length of the main pipe 12 and the control unit.

[0032] Specifically, firstly, among all salt cavern unit branches connected to the main pipe 12, the longest branch is identified as the main control reference branch, which has the largest natural total resistance and serves as a reference standard. Subsequently, pressure data before the valve is collected through the first pressure measuring point 9 of the main control reference branch, and pressure data after the valve is collected through the second pressure measuring point 7. Combined with the gas flow data of this branch collected by the bidirectional flowmeter 11, the natural total resistance of the main control reference branch is calculated through fluid mechanics. The natural total resistance is the target total resistance reference value, and the regulation of all subordinate branches (other salt cavern unit branches besides the main control reference branch) is based on this target total resistance reference value.

[0033] Based on this benchmark value, the control unit calculates the theoretical artificial pressure drop required for each subordinate branch. The control unit collects the natural physical resistance data of each subordinate branch through the first pressure measuring point 9 and the second pressure measuring point 7. The difference between the natural physical resistance of each subordinate branch and the target total resistance benchmark value is calculated, and the resulting difference is the theoretical artificial pressure drop required for each subordinate branch. The theoretical artificial pressure drop is compensated for by the throttling effect of the regulating valve 8, making the resistance difference between the subordinate branches and the main control benchmark branch equal to the target total resistance benchmark value, thus balancing the equivalent resistance of all branches.

[0034] The control unit converts the theoretical artificial pressure drop value required for each subordinate branch into a theoretical valve opening command corresponding to the regulating valve 8 of each subordinate branch through the valve flow characteristic curve, and sends it to the regulating valve 8 of each subordinate branch. After sending the theoretical valve opening command, the control unit monitors the gas temperature after the regulating valve 8 of each subordinate branch in real time through the temperature measuring point 6, and performs temperature correction on the theoretical valve opening command. If the temperature measuring point 6 detects that the gas temperature after the regulating valve 8 of a certain subordinate branch is greater than or equal to the preset safe temperature threshold, the theoretical valve opening command of that branch is maintained without opening adjustment, and the current artificial pressure drop is maintained; if the temperature measuring point 6 detects that the gas temperature after the regulating valve 8 of a certain subordinate branch is less than the preset safe temperature threshold, the opening of the electric regulating valve 8 of that branch is increased, the valve throttling intensity is reduced, and the temperature drop caused by the Joule-Thomson effect is reduced, until the gas temperature after the regulating valve 8 of that branch rises back above the safe temperature threshold.

[0035] The preset safe temperature threshold is set to -10°C. When the control unit detects that the gas temperature is less than -10°C through the temperature measuring point 6, it increases the opening of the electric regulating valve 8 of the branch at a rate of 5% per second, and continues to adjust until the gas temperature rises back to ≥-10°C, ensuring the timeliness and stability of temperature protection, avoiding problems such as pipeline freezing and valve brittleness damage caused by excessively low temperature, and ensuring the safe operation of the branch.

[0036] When the control unit adjusts the opening of the regulating valve 8 of each subordinate branch according to the actual opening command after temperature correction, it simultaneously monitors the pressure change rate inside each salt cavern in real time through the pressure monitoring component of each salt cavern unit. This provides pressure safety limits for the adjustment process of the regulating valve 8, preventing damage to the salt cavern due to sudden pressure changes. Specifically, the control unit compares the real-time monitored pressure change rate inside the salt cavern with this threshold. If the monitored pressure change rate of a certain salt cavern is less than the geologically permissible pressure change rate threshold, the control unit continues to adjust the regulating valve 8 of the corresponding branch of that salt cavern according to the actual opening command after temperature correction. If the monitored pressure change rate of a certain salt cavern is greater than or equal to the geologically permissible pressure change rate threshold, the control unit limits the adjustment rate of the regulating valve 8 of that branch, slowing down the opening adjustment speed to avoid excessively rapid pressure changes in the salt cavern, and then obtains a new flow regulation command.

[0037] After receiving the flow regulation command, the control unit outputs the final control command based on the flow regulation command and the branch lengths of each salt cavern unit connected to the main pipe 12, controlling each branch regulating valve 8 to open and load to the target opening degree according to a preset timing sequence: First, the regulating valve 8 of the branch with the longest connection length to the main pipe 12 (i.e., the main control reference branch) is opened to establish a stable airflow and provide a reference for other branches; after the first preset delay, the regulating valve 8 of the branch with the second longest connection length to the main pipe 12 is opened; according to the above branch length from longest to shortest, the regulating valves 8 of the remaining subordinate branches are opened in sequence, and after the regulating valve 8 of each branch is opened, it is slowly loaded to the target opening degree required by the flow regulation command according to the ramp function.

[0038] During the energy storage phase, the control unit regulates the opening of each branch regulating valve 8 according to the above process to make the gas injection flow of each salt cavern unit more consistent; during the energy release phase, the control unit also regulates the opening of each branch regulating valve 8 according to the above process to make the energy release flow of each salt cavern unit more consistent.

[0039] Throughout the entire control process, the control unit receives real-time data from the first pressure measuring point 9, the second pressure measuring point 7, the temperature measuring point 6, the bidirectional flow meter 11, and the salt cavern pressure monitoring component, and dynamically adjusts the control commands. For example, the multi-branch airflow equalization control system includes six salt cavern units, with branch lengths of 8.0km, 6.0km, 5.0km, 3.0km, 1.5km, and 0.2km respectively connected to the main pipe 12. Figure 3 As shown, the control unit first establishes the 8.0km-long branch as the main control reference branch and calculates the target total resistance reference value. Then, it calculates the theoretical artificial pressure drop values ​​of the remaining 5 subordinate branches and converts them into theoretical valve opening commands. It monitors the gas temperature after the regulating valve 8 of each branch in real time. If the temperature of a branch is lower than -10°C, the opening of the regulating valve 8 of that branch is increased at a rate of 5% per second until the temperature rises back to above -10°C, thus obtaining the actual opening command. When adjusting the opening, if the pressure change rate of a salt cave reaches the geological allowable threshold, the adjustment rate of the regulating valve 8 is limited, and the flow rate adjustment command is obtained. Finally, the regulating valves 8 of each branch are opened in order of branch length from longest to shortest, and the slope function is applied to the target opening to achieve balanced control of the airflow in the entire multi-branch system.

[0040] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

Claims

1. A multi-branch airflow equalization control system for non-uniform salt cavern energy storage, characterized in that: The system includes a main pipe (12), which is connected to an energy storage unit, an energy release unit, and several salt cavern units. The energy storage unit injects gas into several salt cavern units through the main pipe (12), and the several salt cavern units generate electricity to the energy release unit through the main pipe (12). Several salt cavern units are electrically connected to a control unit to feed back the operating parameters of each salt cavern unit to the control unit. Each salt cavern unit includes a regulating valve (8), which is electrically connected to the control unit to receive valve opening adjustment commands issued by the control unit.

2. The multi-branch airflow equalization control system for non-uniform salt cavern energy storage according to claim 1, characterized in that: The energy storage unit includes a compressor system (1), a check valve (2) and a control valve (3) connected in sequence. One end of the control valve (3) is connected to the main pipe (12) and the other end is connected to the check valve (2). The energy release unit includes an intake control valve (5) and an expander (4) connected in sequence. One end of the intake control valve (5) is connected to the main pipe (12), and the other end is connected to the expander (4).

3. The multi-branch airflow equalization control system for non-uniform salt cavern energy storage according to claim 1, characterized in that: The salt cave unit also includes a bidirectional flow meter (11) and an electric valve (10) connected in sequence. One end of the bidirectional flow meter (11) is connected to the main pipe (12), and the other end is connected to the electric valve (10). A first pressure measuring point (9) is provided between the electric valve (10) and the regulating valve (8). A second pressure measuring point (7) and a temperature measuring point (6) are provided between the regulating valve (8) and the salt cave.

4. The multi-branch airflow equalization control system for non-uniform salt cavern energy storage according to claim 3, characterized in that: The first pressure measuring point (9) is set on the inlet side of the regulating valve (8) to detect the pressure before the valve; the second pressure measuring point (7) is set on the outlet side of the regulating valve (8) to detect the pressure after the valve. The control unit adjusts the opening of the regulating valve (8) according to the values ​​of the first pressure measuring point (9) and the temperature measuring point (6).

5. The multi-branch airflow equalization control system for non-uniform salt cavern energy storage according to claim 4, characterized in that: The regulating valve (8) is an electric regulating valve.

6. A method for equalizing and controlling the multi-branch airflow in non-uniform salt cavern energy storage, characterized in that, The multi-branch airflow equalization control system for non-uniform salt cavern energy storage according to any one of claims 1-5 includes the following steps: The control unit is connected to the longest salt cave unit in the main pipe (12) among several salt cave units, and the target total resistance reference value is obtained based on the main control reference branch. The control unit calculates the theoretical artificial pressure drop required for each subordinate branch based on the target total resistance benchmark value; The theoretical artificial pressure drop value required for each subordinate branch is converted into a theoretical valve opening command, and the gas temperature after the electric regulating valve of the subordinate branch is monitored. If the gas temperature is less than the preset safe temperature threshold, the opening of the electric regulating valve of that branch is increased, and the actual opening command after temperature correction is obtained. When the control unit adjusts the regulating valve (8) according to the actual opening command, it simultaneously monitors the pressure change rate inside each salt cave. If the pressure change rate is greater than or equal to the geological allowable pressure change rate threshold, the adjustment rate of the regulating valve (8) is limited, and a flow regulation command is obtained. The control unit outputs control commands based on the flow regulation command and the length of the main pipe (12) and the control unit.

7. The multi-branch airflow equalization control method for non-uniform salt cavern energy storage according to claim 6, characterized in that: The control unit outputs control commands based on the flow regulation command and the length of the main pipe (12) and the control unit, including: First, open the longest regulating valve (8) of the main pipe (12) and control unit. After the first preset delay, open the regulating valve (8) of the second longest branch of the main pipe (12) and control unit. Gradually load to the target opening required by the flow regulation command according to the ramp function.

8. The multi-branch airflow equalization control method for non-uniform salt cavern energy storage according to claim 6, characterized in that: The pressure change rate is less than the geologically permissible pressure change rate threshold, and is adjusted according to the actual opening command after temperature correction.

9. The multi-branch airflow equalization control method for non-uniform salt cavern energy storage according to claim 6, characterized in that: The gas temperature is greater than or equal to a preset safe temperature threshold, maintaining the theoretical valve opening command.

10. The multi-branch airflow equalization control method for non-uniform salt cavern energy storage according to claim 9, characterized in that: When the gas temperature is less than -10°C, the control unit increases the opening of the branch electric regulating valve at a rate of 5% per second until the gas temperature rises back to ≥-10°C.

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