A constant pressure compressed air energy storage system and method combined with pumped storage

Abstract

The application discloses a constant-pressure compressed air energy storage system and method combined with pumped storage, and belongs to the technical field of physical energy storage systems. The constant-pressure energy storage system comprises a pumped storage subsystem, a turbine expansion generation subsystem, a compressed air energy storage subsystem and a water-gas coexistence cabin constant-pressure subsystem. The application can realize independent energy storage and power generation operation among the pumped storage subsystem, the air compression subsystem and the turbine expansion subsystem by flexibly controlling the operation modes of the subsystems and the valve opening and closing states among the subsystems. The design improves the flexibility and reliability of the system, and enables the system to be optimally configured and operated according to actual requirements, thereby further improving the energy storage efficiency and economic benefits.

Description

Technical Field

[0001] This invention belongs to the technical field of electrical energy physical energy storage systems, specifically relating to a constant pressure compressed air energy storage system and method combined with pumped storage. Background Technology

[0002] In the field of energy storage and conversion, pumped hydro storage and compressed air energy storage (CSP) are two important energy storage methods, each with its unique advantages and application scenarios. Pumped hydro storage utilizes the water level difference between reservoirs to pump and release water, achieving the storage and release of electrical energy. It features mature technology, large storage capacity, and flexible operation. Compressed air energy storage, on the other hand, stores and converts energy by compressing and releasing high-pressure air, offering advantages such as high storage efficiency and fewer geographical limitations.

[0003] With the continuous growth of energy demand and the optimization and adjustment of the energy structure, how to efficiently and flexibly utilize and store renewable energy has become an urgent problem to be solved. Although traditional pumped hydro storage systems are technologically mature, they are greatly limited by geographical conditions and have high construction costs. Compressed air energy storage systems, while having strong geographical adaptability, have relatively low air utilization rates and overall efficiency of turbines and air compressors during the energy storage and release process due to the large amount of gas at the bottom.

[0004] To overcome the limitations of the aforementioned technologies, hybrid energy storage systems combining pumped hydro storage and compressed air energy storage have emerged in recent years. Patent CN118030473A discloses a constant-pressure energy storage system and method combining pumped hydro storage and compressed air energy storage. This type of system, through ingenious design, achieves complementary advantages between the two energy storage technologies, improving energy storage efficiency and flexibility. However, during operation, the operation of key components such as the water pump turbine, air compressor, and water-air co-containment chamber often depends on each other, limiting the system's independent operation capability and flexibility.

[0005] Specifically, in existing technologies, the turbine expansion power generation system and air compression subsystem are typically tightly coupled with the pumped-storage subsystem, working together. When the pump-turbine is in power generation mode, the turbine also operates simultaneously; when the pump-turbine is in pumping mode, the air compressor also operates simultaneously, achieving energy conversion and storage through a water-air co-containment chamber. While this design improves the overall system efficiency and installed capacity to some extent, it also causes mutual constraints between the various subsystems, making independent adjustment and optimization based on actual needs impossible. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a constant-pressure compressed air energy storage system and method combined with pumped storage, wherein key components such as the water pump turbine, water-air co-containment chamber, turbine, and air compressor operate independently. By flexibly controlling the operating modes of each subsystem and the valve on / off states between them, the system of the present invention can achieve independent energy storage and power generation operations among the pumped storage subsystem, the air compression subsystem, and the turbine expansion subsystem. This design not only improves the system's flexibility and reliability but also allows the system to be optimally configured and operated according to actual needs, thereby further improving energy storage efficiency and economic benefits.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] A constant-pressure compressed air energy storage system combined with pumped storage includes a pumped water storage subsystem, a turbine expansion power generation system, an air compression subsystem, and a water-air co-containment chamber constant-pressure subsystem.

[0009] The constant pressure subsystem of the water-air co-containment chamber includes a water-air co-containment chamber, the upper layer of which is used to store high-pressure air, and the lower layer of which is used to store water.

[0010] The pumped-storage subsystem is connected to the power grid system. The pumped-storage subsystem includes an upper reservoir that is higher than the water-air co-containment chamber and a lower reservoir that is lower than the upper reservoir but higher than the water-air co-containment chamber. The pumped-storage subsystem is configured such that when generating electricity, the pumped-storage subsystem can generate electricity by utilizing the liquid level difference between the upper reservoir and the lower reservoir; when storing energy, the pumped-storage subsystem can use the electrical energy of the power grid system to pump water from the lower reservoir into the upper reservoir.

[0011] The turbine expansion power generation system is connected to the power grid system, and the turbine expansion power generation system is connected to the upper layer of the water-air co-containment chamber. The turbine expansion power generation system is configured such that when generating electricity, the turbine expansion power generation system is driven by the high-pressure air in the upper layer of the water-air co-containment chamber to convert mechanical energy into electrical energy and transmit it to the power grid system.

[0012] The air compression subsystem is connected to the power grid system and to the upper layer of the water-air co-containment chamber. The air compression subsystem is configured such that, during energy storage, it can use the electrical energy of the power grid system to convert outdoor air into high-pressure air, which enters the water-air co-containment chamber and pressurizes the water in the water-air co-containment chamber into the upper reservoir.

[0013] In the above scheme, the constant-pressure compressed air energy storage system combined with pumped storage is configured to extend a branch tunnel from the lower horizontal tunnel of the main water intake tunnel of the pumped storage power station, connecting with a sealed artificial chamber and construction adit to form a sealed constant-pressure water-air co-containment chamber system, serving as the gas storage tank for the compressed air energy storage power station. This constant-pressure compressed air energy storage system combined with pumped storage utilizes the ultra-high water column pressure formed by the upper reservoir to compress the bottom gas volume of the artificial chamber gas storage tank, thereby constructing a constant-pressure water-air co-containment chamber subsystem. This significantly reduces the bottom gas volume in the gas storage tank. Simultaneously, during turbine gas release for power generation and air compressor gas filling for energy storage, the water-air co-containment chamber maintains a essentially constant pressure, ensuring that the turbine and air compressor operate consistently in their high-efficiency range. This improves the power generation time and overall utilization efficiency of the compressed air energy storage power station, and also significantly reduces the volume of the gas storage tank for the same installed capacity. During power generation, water from the upper reservoir in the pumped-storage subsystem flows to the lower reservoir and the water-air co-current chamber in the constant-pressure subsystem of the water-air co-current chamber. The pump turbine operates as a turbine, and the water level in the water-air co-current chamber rises. High-pressure gas is then pumped into the turbine in the compressed air energy storage subsystem to generate electricity. During energy storage, water from the lower reservoir in the pumped-storage subsystem and the water pressure in the water-air co-current chamber of the constant-pressure subsystem of the water-air co-current chamber are pumped to the upper reservoir. The pump turbine operates as a pump, and the air compressor injects high-pressure air into the water-air co-current chamber, causing the water level to drop. This constant-pressure compressed air energy storage system combined with pumped-storage can significantly increase the installed capacity of the entire energy storage system with limited increase in civil engineering costs. It organically combines pumped-storage power station technology with compressed air energy storage power station technology, and has a wide range of applications and strong adaptability.

[0014] As a further optimization of the present invention, the upper reservoir is connected to the first water pump turbine via a main water intake tunnel and a first water intake branch tunnel; the upper reservoir is connected to the second water pump turbine via a main water intake tunnel and a second water intake branch tunnel; the upper reservoir is connected to the bottom of the water-air co-containment chamber via a main water intake tunnel and a third water intake branch tunnel; the first water pump turbine is connected to the lower reservoir via a first tailrace branch tunnel and a tailrace main tunnel; the first water pump turbine and the second water pump turbine are respectively connected to the first generator motor and the second generator motor, and connected to the power grid system via an outlet busbar, a transformer, and a high-voltage cable; a first inlet ball valve is installed on the first water intake branch tunnel in front of the first water pump turbine; a second inlet ball valve is installed on the second water intake branch tunnel in front of the second water pump turbine; and a third inlet ball valve is installed on the third water intake branch tunnel.

[0015] As a further optimization of the present invention, a first level transmitter is installed in the upper reservoir, a second level transmitter is installed in the lower reservoir, and a water hammer elimination tank is installed on the main water intake tunnel; a first tailrace butterfly valve is installed on the first tailrace branch tunnel after the first water pump turbine, and a second tailrace butterfly valve is installed on the second tailrace branch tunnel after the second water pump turbine.

[0016] As a further optimization of the present invention, the constant pressure subsystem of the water-air coexistence chamber further includes a third pressure transmitter, a third temperature transmitter, a safety valve, and a spray system installed on the upper layer of the water-air coexistence chamber. The spray system is connected to the main water intake tunnel through a pressure reducing valve and a water supply pipeline. The third pressure transmitter is used to monitor the air pressure in the upper layer of the water-air coexistence chamber in real time, the third temperature transmitter is used to monitor the air temperature in the upper layer of the water-air coexistence chamber in real time, and the safety valve is used to automatically release pressure when the air pressure in the upper layer of the water-air coexistence chamber reaches the limit value. A third liquid level transmitter is installed on the lower layer of the water-air coexistence chamber to monitor the water level in the water-air coexistence chamber in real time.

[0017] As a further optimization of the present invention, the water-air co-containment chamber includes a steel plate sealing layer and a concrete lining located outside the steel plate sealing layer. A water curtain is formed between the steel plate sealing layer and the concrete lining. The water curtain is connected to the main water intake tunnel through a ball valve and a water supply pipe. A fourth pressure transmitter is installed above the water curtain for real-time monitoring of the pressure of the water curtain.

[0018] As a further optimization of the present invention, the elevation of the water-air co-containment chamber is basically the same as that of the first water intake branch tunnel, the second water intake branch tunnel, the third water intake branch tunnel, the first water pump turbine, and the second water pump turbine.

[0019] In the above scheme, the constant-pressure water-air co-containment chamber subsystem is located underground and is constructed by modifying and expanding the construction adit of the pumped-storage power station. The geological conditions along the pumped-storage power station's water conveyance system and powerhouse system are generally favorable, and both the upper and lower reservoirs of the pumped-storage power station have a certain capacity margin. Therefore, the combination of the constant-pressure water-air co-containment chamber subsystem and the pumped-storage power station has inherent advantages. Furthermore, the constructed constant-pressure water-air co-containment chamber system integrated with the pumped-storage power station can significantly increase the installed capacity of the entire energy storage power station with limited increase in civil engineering costs. It organically combines pumped-storage power station technology with compressed air energy storage power station technology, offering broad application scenarios and strong adaptability.

[0020] As a further optimization of the present invention, the turbine expansion power generation system includes a first heat exchanger, a turbine, and a gas storage tank connected in sequence. The gas storage tank is used to provide a constant gas source for the low-pressure gas users of the power plant. The first heat exchanger is connected to the heat storage tank through a first heat medium conveying pipeline. The heat storage tank is used to store the heat generated by the air compression subsystem during energy storage. A third generator motor is also connected to the turbine. The third generator motor is connected to the power grid system through an outlet bus, a transformer, and a high-voltage cable. When generating electricity, the turbine expands and does work, and the third generator motor rotates clockwise.

[0021] As a further optimization of the present invention, one end of the first heat exchanger is connected to the upper layer of the water-gas co-containment chamber via a second gas pipeline and a first gas pipeline; a first pressure transmitter and a first temperature transmitter are installed on the second gas pipeline between the other end of the first heat exchanger and the turbine; a first gas pipeline ball valve is installed on the second gas pipeline between the first heat exchanger and the water-gas co-containment chamber; and a third gas pipeline ball valve is installed on the second gas pipeline between the turbine and the gas storage tank.

[0022] As a further optimization of the present invention, the air compression subsystem includes a second heat exchanger, an air compressor, and an air filter connected in sequence. The second heat exchanger is connected to the heat storage tank through a second heat medium conveying pipeline. The air compressor can also be used to provide air source for medium-pressure gas users in the power plant. A third generator motor is also connected to the air compressor. During energy storage, the air compressor compresses air, and the third generator motor rotates counterclockwise.

[0023] As a further optimization of the present invention, one end of the second heat exchanger is connected to the upper layer of the water-air coexistence chamber via a third gas pipeline and a first gas pipeline. A second pressure transmitter and a second temperature transmitter are installed on the third gas pipeline between the other end of the second heat exchanger and the air compressor. A second gas pipeline ball valve is installed on the third gas pipeline between the second heat exchanger and the water-air coexistence chamber.

[0024] A control method for a constant-pressure compressed air energy storage system combined with pumped storage includes the following steps:

[0025] Before starting energy storage, close the first water inlet ball valve, the second water inlet ball valve, the first gas pipeline ball valve, the second gas pipeline ball valve, and the third gas pipeline ball valve. Open the third water inlet ball valve and the ball valve to fill the water-air co-containment chamber and the water curtain with water. At the same time, open the second gas pipeline ball valve, and the air compressor starts working. The air compressor compresses the outdoor gas filtered by the air filter into high-pressure air and injects it into the water-air co-containment chamber, so that the gas pressure inside the water-air co-containment chamber is equal to the pressure formed by the height difference between the upper reservoir and the water-air co-containment chamber. At this time, the initial constant pressure system of the water-air co-containment chamber is completed. The air compressor stops working, and the ball valves and the second gas pipeline ball valve are closed.

[0026] When renewable energy generation decreases sharply or electricity demand increases, leading to insufficient power in the grid system, and it is necessary to operate in power generation mode, any one of the following three methods can be adopted according to actual needs:

[0027] In the first method, the pumped storage subsystem generates electricity independently: the third inlet ball valve is closed, and the first and second inlet ball valves are opened. Water flows from the upper reservoir to the lower reservoir. The first and second pump turbines operate in power generation mode, converting the potential energy of the upper reservoir into mechanical energy, which is then converted into electrical energy by the first and second generator motors and transmitted to the power grid system via a transformer. During this time, the turbines, air compressors, and water-air co-containment chamber do not operate. When the upper reservoir is lowered to the dead water level, or the lower reservoir is raised to the normal storage level, or when the power system does not need to operate in power generation mode, the system stops generating electricity.

[0028] The second method involves the turbine expansion subsystem generating electricity independently: the first inlet ball valve, the second inlet ball valve, and the second gas pipeline ball valve are closed, while the third inlet ball valve and the first gas pipeline ball valve are opened. Water from the upper reservoir flows into the water-air co-containment chamber, and the high-pressure air at the top of the chamber drives the turbine to perform work. The mechanical energy generated by the turbine's rotation is converted into electrical energy by the third generator motor and transmitted to the power grid system via a transformer. At this time, the first water pump turbine, the second water pump turbine, and the air compressor are not working. When the upper reservoir is lowered to the dead water level, or the water level in the water-air co-containment chamber rises to the highest operating level, or when the power system does not need to operate in power generation mode, the system stops generating electricity.

[0029] The third method involves simultaneous power generation by the pumped storage subsystem and the turbine expansion subsystem: The second gas pipeline ball valve is closed, while the first, second, and third inlet ball valves are opened. The first and second pump turbines operate in power generation mode, converting the potential energy of the upper reservoir into mechanical energy, which is then converted into electrical energy via the first and second generator motors and transmitted to the power grid system through a transformer. Simultaneously, as water flows from the upper reservoir to the lower reservoir, the water-air co-containment chamber and the turbine operate. The high-pressure air at the top of the chamber drives the turbine, and the mechanical energy generated by the turbine's rotation is converted into electrical energy via the third generator motor and transmitted to the power grid system through a transformer. When the upper reservoir drops to a dead storage level, the lower reservoir rises to a normal storage level, the water level in the water-air co-containment chamber rises to the highest operating level, or the power system no longer requires power generation, the system stops generating electricity.

[0030] When renewable energy generation increases sharply or electricity demand decreases, resulting in a surplus of electricity in the power grid system, and energy storage is required, any one of the following three methods can be adopted according to actual needs:

[0031] The first method involves independent energy storage by the pumped storage subsystem: The third inlet ball valve is closed, while the first and second inlet ball valves are opened. The first and second pump turbines operate in pumping mode. The power grid system transmits electrical energy via transformers to the first and second generator motors, converting it into mechanical energy. This mechanical energy is then converted into water potential energy by the first and second pump turbines, pumping water from the lower reservoir into the upper reservoir. During this time, the turbines, air compressors, and water-air co-containment chambers are not operating. The system stops storing energy when the lower reservoir drops to a dead storage level, the upper reservoir rises to a normal storage level, or the power system no longer requires energy storage.

[0032] The second method involves independent energy storage by the air compressor subsystem: The first inlet ball valve, the second inlet ball valve, the first air pipeline ball valve, and the third air pipeline ball valve are closed. The third inlet ball valve and the second air pipeline ball valve are opened. The power grid system transmits electrical energy to the air compressor via a transformer. The air compressor starts, converting filtered outdoor air into high-pressure gaseous air, which is then forced into the water-air co-containment chamber. The water level in the water-air co-containment chamber gradually decreases, and the water flows through the third water intake branch into the main water intake tunnel and then into the upper reservoir. When the air compressor and the water-air co-containment chamber are operating, the water pressure from the water-air co-containment chamber is sent to the upper reservoir. At this time, the first and second water pump turbines are not operating. When the water level in the water-air co-containment chamber drops to the minimum operating level, or the upper reservoir rises to the normal storage level, or when the power system does not require energy storage, the system stops storing energy.

[0033] The third method involves simultaneous energy storage via a pumped-storage subsystem and an air compression subsystem: The first and third air pipeline ball valves are closed, while the second, first, second, and third air pipeline ball valves, the first water inlet ball valve, the second water inlet ball valve, and the third water inlet ball valve are opened. The power grid system transmits electrical energy to the air compressor via a transformer. The air compressor starts, converting filtered outdoor air into high-pressure gaseous air, which is then forced into the water-air co-containment chamber. The water level in the chamber gradually decreases, and the water flows into the main water diversion tunnel through the third diversion branch tunnel. The water flows into the upper reservoir; simultaneously, the first and second pump turbines operate in pumping mode, and the power grid system transmits electrical energy to the first and second generator motors via transformers, converting it into mechanical energy, which is then converted into water potential energy through the first and second pump turbines, pumping the water from the lower reservoir into the upper reservoir; when the water level in the water-air co-containment chamber drops to the minimum operating level, or the lower reservoir drops to the dead water level, or the upper reservoir rises to the normal storage level, or when the power system does not require energy storage, the system stops storing energy.

[0034] Compared with the prior art, the present invention has the following significant advantages:

[0035] (1) Compared with the compressed air energy storage technology in related technologies, the present invention effectively combines pumped storage technology and compressed air energy storage technology. It utilizes the construction adit of the pumped storage power station to transform it into a constant pressure water-air co-containment chamber. The liquid level difference between the upper reservoir and the bottom of the water-air co-containment chamber forms a constant pressure, which can greatly reduce the amount of bottom gas and pressure fluctuation in the gas storage tank of the traditional compressed air energy storage device, thereby greatly improving the working efficiency of the air compressor and turbine, further improving the utilization rate of compressed air and the overall efficiency of the system. At the same time, it can reduce the volume of the gas storage tank of the traditional compressed air energy storage device and reduce construction investment.

[0036] (2) This invention cleverly combines the compressibility of air and the incompressibility of water, greatly improving the efficiency of air compression and air expansion. At the same time, the combination of pumped water storage technology and compressed air energy storage technology can significantly increase the installed capacity of the entire energy storage power station while increasing civil engineering costs by a limited amount. It can better play the roles of peak shaving, valley filling and phase adjustment, and has a wide range of applications and strong adaptability.

[0037] (3) The present invention cleverly replaces the pressure regulating well with the water hammer elimination tank and the tailwater butterfly valve with the tailwater emergency gate; at the same time, the gas storage tank in the turbine expansion generator system is used to provide a constant gas source for low-pressure gas users such as braking and purging in the power station; the air compressor in the air compression subsystem can be used to provide a gas source for medium-pressure gas users such as phase adjustment and oil pressure devices in the power station, thereby saving a lot of equipment investment and construction costs.

[0038] (4) Compared with the water curtain sealing technology that requires water pump pressurization in related technologies, the present invention ingeniously draws water from the main water intake tunnel to form a water curtain that is basically consistent with the pressure of the water-air coexistence chamber and can be maintained continuously. There is no need to set up a separate water pump pressurization system. The water curtain and the steel plate sealing layer form a double sealing structure, which prevents the high-pressure air in the upper layer of the water-air coexistence chamber from leaking to the surroundings and can achieve a good sealing effect. At the same time, the water for spraying is also drawn from the main water intake tunnel, so there is no need to set up a separate water pump pressurization system, thereby saving equipment investment. In addition, the water-air pressure in the water-air coexistence chamber is basically consistent with the water curtain pressure, and the pressure of the steel plate sealing layer on the outer wall of the water-air coexistence chamber is small, which can greatly reduce the required thickness of the steel plate sealing layer. At the same time, the system has good safety and stability.

[0039] (5) Addressing the problem in existing technologies where the turbine expansion power generation system / air compression subsystem and pumped storage subsystem operate simultaneously, with each subsystem constraining the others and unable to be independently adjusted and optimized according to actual needs, the system design of this invention allows the pumped storage subsystem, air compression subsystem, and turbine expansion subsystem to operate independently or in combination, providing multiple energy storage and power generation modes. This flexibility enables the system to be optimized and adjusted according to the actual needs of the power grid and the fluctuations in renewable energy, improving the system's response speed and adaptability. Because the system can flexibly select energy storage and power generation modes according to actual conditions, and the operation of each subsystem is independent, renewable energy can be utilized to the maximum extent, reducing energy waste. The system design of this invention has good scalability and adaptability, and can be flexibly adjusted and optimized according to factors such as power grid scale, renewable energy distribution, and user needs. This design enables the system to better adapt to future changes and demands in the energy market.

[0040] (6) In existing technologies, the water-air co-containment chamber generally serves as the lower reservoir. Considering the need for a significant burial depth for the pump turbine, the elevation of the water-air co-containment chamber must be higher than that of the pump turbine. This reduces the elevation difference between the upper reservoir and the water-air co-containment chamber, thus decreasing the energy storage / generation capacity. To address this, this application proposes a design where the elevation of the water-air co-containment chamber is essentially the same as that of the water diversion tunnel and the pump turbine, but lower than that of the lower reservoir. This eliminates the need for the water-air co-containment chamber to serve as the lower reservoir, increasing the elevation difference between the upper reservoir and the water-air co-containment chamber, thereby increasing the energy storage / generation capacity.

[0041] (7) In this invention, the air compressor and the turbine share the same third generator motor, which can save on equipment investment and factory floor space. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the constant-pressure compressed air energy storage system that combines the present invention with pumped hydro storage.

[0043] In the diagram: 1. Upper Reservoir; 2. Main Intake Tunnel; 3. Water Hammer Elimination Tank; 4a. First Intake Branch Tunnel; 4b. Second Intake Branch Tunnel; 4c. Third Intake Branch Tunnel; 5a. First Intake Ball Valve; 5b. Second Intake Ball Valve; 5c. Third Intake Ball Valve; 6a. First Pump Turbine; 6b. Second Pump Turbine; 7a. First Tailwater Branch Tunnel; 7b. Second Tailwater Branch Tunnel; 8. Tailwater Main Tunnel; 9. Lower Reservoir; 10. Water-Air Co-containment Chamber; 11a. First Gas Pipeline; 11b. Second Gas Pipeline; 11c. Third Gas Pipeline; 12a. First Gas Pipeline Ball Valve; 12b. Second Gas Pipeline Ball Valve; 12c. Third Gas Pipeline Ball Valve; 13a. First Heat Exchanger; 13b. Second Heat Exchanger; 14a. First Heat Medium Transport Pipeline; 14b. Second Heat Medium Transport Pipeline; 1 5. Thermal storage tank; 16. Turbine; 17. Air compressor; 18. Third generator motor; 19. Air filter; 20. Gas storage tank; 21a. First generator motor; 21b. Second generator motor; 22a. First tailrace butterfly valve; 22b. Second tailrace butterfly valve; 23a. First temperature transmitter; 23b. Second temperature transmitter; 23c. Third temperature transmitter; 24. Safety valve; 25a. First pressure transmitter; 25b. Second pressure transmitter; 25c. Third pressure transmitter; 25d. Fourth pressure transmitter; 26. Sprinkler; 27. Pressure reducing valve; 28. Ball valve; 29. ​​Water pipeline; 30a. First level transmitter; 30b. Second level transmitter; 30c. Third level transmitter; 31. Water curtain; 32. Concrete lining; 33. Steel plate sealing layer. Detailed Implementation

[0044] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples. However, it should be understood that the accompanying drawings are for illustrative purposes only and should not be construed as limiting the present patent. For better illustration of this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. For those skilled in the art, the omission of certain well-known structures and their descriptions in the drawings is understandable. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present patent.

[0045] like Figure 1As shown, this embodiment of a constant-pressure compressed air energy storage system combined with pumped storage mainly includes the following components: reservoir 1, main water intake tunnel 2, water hammer elimination tank 3, first water intake branch tunnel 4a, second water intake branch tunnel 4b, first inlet ball valve 5a, second inlet ball valve 5b, first pump turbine 6a, second pump turbine 6b, first tailrace branch tunnel 7a, second tailrace branch tunnel 7b, tailrace main tunnel 8, lower reservoir 9, first tailrace butterfly valve 22a, second tailrace butterfly valve 22b, first generator motor 21a, second generator motor 21b, first level transmitter 30a, and second level transmitter 30b; and a pumped storage subsystem represented by the third water intake branch tunnel 4c, third inlet ball valve 5c, and water-air co-containment chamber 10. The water-gas co-containment chamber constant pressure subsystem is represented by the first gas transmission pipeline 11a, the third temperature transmitter 23c, the safety valve 24, the third pressure transmitter 25c, the fourth pressure transmitter 25d, the spray 26, the pressure reducing valve 27, the ball valve 28, the water transmission pipeline 29, the third liquid level transmitter 30c, the water curtain 31, the concrete lining 32, and the steel plate sealing layer 33; the turbine expansion generator system is represented by the second gas transmission pipeline 11b, the first gas transmission pipeline ball valve 12a, the third gas transmission pipeline ball valve 12c, the first heat exchanger 13a, the first heat medium transmission pipeline 14a, the heat storage tank 15, the turbine 16, the third generator motor 18, the gas storage tank 20, the first temperature transmitter 23a, and the first pressure transmitter 25a. The compressed air energy storage subsystem is represented by the third gas pipeline 11c, the second gas pipeline ball valve 12b, the second heat exchanger 13b, the second heat medium conveying pipeline 14b, the heat storage tank 15, the air compressor 17, the third generator motor 18, the second temperature transmitter 23b, and the second pressure transmitter 25b.

[0046] In a pumped storage subsystem, taking a common one-tunnel-two-turbine configuration as an example, a first level transmitter 30a is installed in the upper reservoir 1, and a second level transmitter 30b is installed in the lower reservoir. The upper reservoir 1 is connected to the first pump-turbine 6a via the main intake tunnel 2 and the first intake branch tunnel 4a. The upper reservoir 1 is also connected to the second pump-turbine 6b via the main intake tunnel 2 and the second intake branch tunnel 4b. A water hammer elimination tank 3 is installed on the main intake tunnel 2. The first pump-turbine 6a is connected to the lower reservoir 9 via the first tailrace branch tunnel 7a and the tailrace main tunnel 8. A first tailrace butterfly valve 22a is installed on the first tailrace branch tunnel 7a after the first pump-turbine 6a, and a second tailrace butterfly valve 22b is installed on the second tailrace branch tunnel 7b after the second pump-turbine 6b. A first inlet ball valve 5a is installed on the first intake branch tunnel 4a before the first water pump turbine 6a, and a second inlet ball valve 5b is installed on the second intake branch tunnel 4b before the second water pump turbine 6b. The first water pump turbine 6a and the second water pump turbine 6b are connected to the first generator motor 21a and the second generator motor 21b, respectively, and are connected to the power grid system via the outlet busbar, transformer, and high-voltage cable. The water hammer elimination tank 3 can replace the surge tank of a traditional pumped storage power station, and the first tailrace butterfly valve 22a and the second tailrace butterfly valve 22b can replace the tailrace emergency gate of a traditional pumped storage power station, respectively serving the functions of flow regulation, pressure regulation, and emergency protection.

[0047] The water-air co-containment constant-pressure subsystem is located underground and serves as the high-pressure air storage tank for the compressed air energy storage subsystem. It was constructed and expanded from the construction adit of the pumped-storage power station. The geological conditions along the pumped-storage power station's water conveyance system and powerhouse system are generally favorable, and both the upper and lower reservoirs of the pumped-storage power station have a certain capacity margin. Therefore, the integration of the water-air co-containment constant-pressure subsystem with the pumped-storage power station has inherent advantages.

[0048] The lower layer of the water-air coexisting chamber 10 in the constant pressure subsystem of the water-air coexisting chamber is connected to the main water intake tunnel 2 of the pumped storage subsystem via the third water intake branch tunnel 4c. The third water inlet ball valve 5c is installed on the third water intake branch tunnel 4c. A third level transmitter 30c is installed on the lower layer of the water-air coexisting chamber 10 to monitor the water level of the water-air coexisting chamber 10 in real time. The constant pressure subsystem of the water-air coexisting chamber also includes a third pressure transmitter 25c, a third temperature transmitter 23c, a safety valve 4, and a spray system 26 installed on the upper layer of the water-air coexisting chamber. The spray system 26 is connected to the main water intake tunnel 2 via a pressure reducing valve 27 and a water supply pipe 29. When the air compressor 17 is working to deliver compressed gas to the water-air coexisting chamber 10, if the third temperature transmitter 23c detects that the temperature of the upper layer of the water-air coexisting chamber 10 is too high, the pressure reducing valve 27 is opened, and the spray system 26 is used to cool the water-air coexisting chamber 10. The third pressure transmitter 25c is used to monitor the air pressure in the upper layer of the water-air co-containment chamber 10 in real time; the third temperature transmitter 23c is used to monitor the air temperature in the upper layer of the water-air co-containment chamber 10 in real time; the safety valve 24 is used to automatically release pressure when the air pressure in the upper layer of the water-air co-containment chamber 10 reaches the limit value, so as to ensure the safety of the water-air co-containment chamber 10.

[0049] The water-air co-containment chamber 10 comprises a steel plate sealing layer 33 and a concrete lining 32 located outside the steel plate sealing layer 33. A cavity exists between the steel plate sealing layer 33 and the concrete lining 32. High-pressure water from the water supply pipe 29 forms a high-pressure water curtain 31, preventing high-pressure air from leaking out of the water-air co-containment chamber 10 and achieving a good sealing effect. The water curtain 31 is connected to the main water intake tunnel 2 via a ball valve 28 and the water supply pipe 29, and is filled with water together with the main water intake tunnel 2. When the water curtain 31 needs replenishment, the ball valve 28 is opened. A fourth pressure transmitter 25d is installed above the water curtain 31 for real-time monitoring of the pressure of the water curtain 31.

[0050] The pressure within the water-air co-containment chamber 10 is kept constant by utilizing the pressure difference between the upper reservoir 1 and the bottom of the water-air co-containment chamber 10. Similarly, the pressure within the water curtain 31 is kept constant by utilizing the pressure difference between the upper reservoir 1 and the water curtain 31. The pressure in the water curtain 31 and the water-air co-containment chamber 10 are essentially balanced. The ambient pressure within the water-air co-containment chamber 10 can be considered constant. During processes such as filling and venting water and air into the water-air co-containment chamber 10, the pressure within it can still be considered constant. Therefore, the constant-pressure water-air co-containment chamber 10 constructed for this purpose can significantly reduce the amount of bottom gas in the gas storage tank of traditional air energy storage devices. The turbine 16 and air compressor 17 can operate in a high-pressure, high-efficiency range for extended periods, thereby improving the overall utilization efficiency of the air compression subsystem and the turbine expansion power generation system. Furthermore, in power generation and energy storage modes, the gas can achieve approximately isothermal expansion / compression, with temperature changes far less than in traditional compressed air energy storage schemes, resulting in higher energy conversion efficiency. Meanwhile, since the water curtain 31 and the water-air co-containment chamber 10 have essentially the same water-air pressure, the outer wall steel plate sealing layer 33 of the water-air co-containment chamber 10 bears little pressure, which can greatly reduce the required thickness of the steel plate sealing layer. At the same time, the system has excellent safety and stability. The water-air co-containment chamber is at the same height as the first water pump turbine 6a and the second water pump turbine 6b. The lower reservoir 9 is lower than the upper reservoir 1 but higher than the water-air co-containment chamber 10, and the lower reservoir 9 is generally about 60m to 80m higher than the water-air co-containment chamber 10.

[0051] In the turbine expansion power generation system, the first heat exchanger 13a, the first gas pipeline ball valve 12a, the first pressure transmitter 25a, and the first temperature transmitter 23a are installed on the second gas pipeline 11b between the turbine 16 and the water-gas co-containment chamber 10. The third gas pipeline ball valve 12c is installed on the second gas pipeline 11b between the turbine 16 and the gas storage tank 20. The gas storage tank 20 is used to provide a constant gas source to the low-pressure gas users of the power plant.

[0052] In the compressed air energy storage subsystem, an air filter 19 is installed before the air compressor 17. The second heat exchanger 13b, the second air transmission pipeline ball valve 12b, the second pressure transmitter 25b, and the second temperature transmitter 23b are installed on the third air transmission pipeline 11c between the air compressor 17 and the water-air co-containment chamber 10. The air compressor 17 can also be used to provide air source for the medium-pressure air users of the power station.

[0053] The heat storage tank 15 is connected to the first heat exchanger 13a through the first heat medium conveying pipe 14a and to the second heat exchanger 13b through the second heat medium conveying pipe 14b. When storing energy, the heat storage tank 15 stores the heat generated by the air compressor 17 in the air compression subsystem. When generating electricity, the heat stored in the heat storage tank 15 is transferred to the high-pressure gas entering the turbine 16, so that the air does not need to be heated by external energy when the turbine 16 is working, thus achieving a non-combustion effect.

[0054] Turbine 16 and air compressor 17 share a third generator motor 18. When generating electricity, turbine 16 expands to do work, and the third generator motor 18 rotates clockwise; when storing energy, air compressor 17 compresses air, and the third generator motor 18 rotates counterclockwise. The third generator motor is connected to the power grid system through the outlet bus, transformer, and high-voltage cable.

[0055] The energy storage mechanism of this invention differs from traditional compressed air energy storage and pumped hydro storage mechanisms. In this invention's system, before energy storage begins, the first gas pipeline ball valve 12a, the second gas pipeline ball valve 12b, and the third gas pipeline ball valve 12c are closed, while the third water inlet ball valve 5c and ball valve 28 are opened to fill the water-air co-containment chamber 10 and the water curtain 31 with water. Simultaneously, the second gas pipeline ball valve 12b is opened, and the air compressor 17 begins to operate. The air compressor 17 compresses the outdoor gas filtered by the air filter 19 into high-pressure air and injects it into the water-air co-containment chamber 10, making the gas pressure inside the water-air co-containment chamber 10 equal to the pressure formed by the height difference between the upper reservoir and the water-air co-containment chamber. At this point, the initial constant pressure system of the water-air co-containment chamber 10 is completed, the air compressor 17 stops operating, and the ball valve 28 and the second gas pipeline ball valve 12b are closed.

[0056] When renewable energy generation decreases sharply or electricity demand increases, leading to insufficient power in the grid system, and this invention needs to operate in power generation mode, any one of the following three methods can be adopted according to actual needs:

[0057] When the power grid system requires a large amount of electricity, or when the turbine expansion subsystem and the water-air co-containment chamber constant pressure subsystem are under maintenance, the first method is adopted, and the pumped storage subsystem generates electricity independently: the third inlet ball valve 5c is closed, and the first inlet ball valve 5a and the second inlet ball valve 5b are opened. The water in the upper reservoir 1 flows to the lower reservoir 9. The first pump turbine 6a and the second pump turbine 6b operate in power generation mode, converting the potential energy of the upper reservoir 1 into mechanical energy, and then converting it into electrical energy through the first generator motor 21a and the second generator motor 21b. The electrical energy is then transmitted to the power grid system via the transformer. At this time, the turbine 16, the air compressor 17, and the water-air co-containment chamber 10 do not work. When the upper reservoir 1 is lowered to the dead water level, or the lower reservoir 9 is raised to the normal storage water level, or when the power system does not need to operate in power generation mode, the system stops generating electricity.

[0058] When the power grid system requires less electricity, and considering the safety hazards such as vibration and hydraulic pulsation that may occur when the pumped storage unit operates at very low output, or when maintenance is required on the tailrace main tunnel 8 of the pumped storage subsystem, the second method is adopted, in which the turbine expansion subsystem generates electricity independently: the first inlet ball valve 5a, the second inlet ball valve 5b, and the second gas pipeline ball valve 12b are closed, and the third inlet ball valve 5c and the first gas pipeline ball valve 12a are opened. The water in the upper reservoir 1 flows to the water-air co-containment chamber 10. The high-pressure air at the top of the water-air co-containment chamber 10 drives the turbine 16 to do work. The mechanical energy generated by the rotation of the turbine 16 is converted into electrical energy by the third generator motor 18 and transmitted to the power grid system via the transformer. At this time, the first water pump turbine 6a, the second water pump turbine 6b, and the air compressor 17 do not work. When the water level in the upper reservoir 1 drops to the dead water level, or the water level in the water-air co-containment chamber 10 rises to the highest operating water level, or when the power system does not need to operate in the power generation mode, the system stops generating electricity.

[0059] When there is a significant power shortage in the power grid system and more generating units are needed, a third method is adopted, where the pumped storage subsystem and the turbine expansion subsystem generate electricity simultaneously: the second gas pipeline ball valve 12b is closed, and the first inlet ball valve 5a, the second inlet ball valve 5b, and the third inlet ball valve 5c are opened. The first pump turbine 6a and the second pump turbine 6b operate in power generation mode, converting the potential energy of the upper reservoir 1 into mechanical energy, which is then converted into electrical energy through the first generator motor 21a and the second generator motor 21b and transmitted to the power grid system via a transformer. Simultaneously, as water flows from the upper reservoir 1 to the lower reservoir 9, the water-air co-containment chamber 10 and the turbine 16 operate. Water from reservoir 1 flows to the water-air co-containment chamber 10. High-pressure air at the top of the water-air co-containment chamber 10 drives turbine 16 to do work. The mechanical energy generated by the rotation of turbine 16 is converted into electrical energy by the third generator motor 18 and transmitted to the power grid system via a transformer. When the upper reservoir 1 drops to the dead water level, or the lower reservoir 9 rises to the normal storage water level, or the water level in the water-air co-containment chamber 10 rises to the highest operating water level, or the power system does not need to operate in the power generation mode, the system stops generating electricity. The first water pump turbine 6a, the second water pump turbine 6b and turbine 16 stop working, and the first inlet ball valve 5a, the second inlet ball valve 5b, the first gas pipeline ball valve 12a and the third gas pipeline ball valve 12c are closed.

[0060] When renewable energy generation increases sharply or electricity load decreases, resulting in a surplus of electricity in the power grid system, and the present invention needs to operate in an energy storage mode, any one of the following three methods can be adopted according to actual needs:

[0061] When the power grid system has a large surplus of electrical energy, or when the air compression subsystem and the water-air co-containment chamber constant pressure subsystem are under maintenance, the first method is adopted, with the pumped storage subsystem storing energy independently: the third inlet ball valve 5c is closed, and the first inlet ball valve 5a and the second inlet ball valve 5b are opened. The first water pump turbine 6a and the second water pump turbine 6b operate in pumping mode. The power grid system transmits electrical energy to the first generator motor 21a and the second generator motor 21b via transformers, converting it into mechanical energy. This mechanical energy is then converted into water potential energy through the first water pump turbine 6a and the second water pump turbine 6b, pumping the water from the lower reservoir 9 into the upper reservoir 1. At this time, the turbine 16, the air compressor 17, and the water-air co-containment chamber 10 do not work. When the lower reservoir 9 drops to the dead water level, or the upper reservoir 1 rises to the normal storage level, or when the power system does not need to operate in the energy storage mode, the system stops storing energy.

[0062] When the power grid has limited surplus power, and considering the difficulty in adjusting the flow rate of the pumped storage unit during pumping operation, making it impossible to operate at low power, or when maintenance is required on the tailrace main tunnel 8 of the pumped storage subsystem, a second method is adopted: the air compressor subsystem independently stores energy. The first inlet ball valve 5a, the second inlet ball valve 5b, the first air pipeline ball valve 12a, and the third air pipeline ball valve 12c are closed; the third inlet ball valve 5c and the second air pipeline ball valve 12b are opened. The power grid system transmits electrical energy to the air compressor 17 via a transformer. The air compressor 17 starts and... Outdoor air filtered by air filter 19 is converted into high-pressure gaseous air and injected into the water-air co-containment chamber 10. The water level in the water-air co-containment chamber 10 gradually decreases, and the water flows into the main water diversion tunnel 2 through the third water diversion branch tunnel 4c and into the upper reservoir 1. When the air compressor 17 and the water-air co-containment chamber 10 are working, the water pressure in the water-air co-containment chamber 10 is sent to the upper reservoir. At this time, the first water pump turbine 6a and the second water pump turbine 6b are not working. When the water level in the water-air co-containment chamber 10 drops to the minimum operating water level, or the upper reservoir 1 rises to the normal storage water level, or the power system does not need to operate in the energy storage mode, the system stops energy storage.

[0063] When the power grid system has a large surplus of electricity and more units are needed for energy storage, a third method is adopted, where the pumped storage subsystem and the air compression subsystem store energy simultaneously: the first air supply pipeline ball valve 12a and the third air supply pipeline ball valve 12c are closed, and the second air supply pipeline ball valve 12b, the first water inlet ball valve 5a, the second water inlet ball valve 5b, and the third water inlet ball valve 5c are opened. The power grid system transmits electrical energy to the air compressor 17 via a transformer. The air compressor 17 starts and converts the outdoor air filtered by the air filter 19 into high-pressure gaseous air, which is then forced into the water-air co-containment chamber 10. The water level in the water-air co-containment chamber 10 gradually decreases, and the water flows into the main water inlet 2 through the third water intake branch tunnel 4c and into the upper reservoir 1; at the same time, the first water pump... When turbine 6a and second pump turbine 6b operate in pumping mode, the power grid system transmits electrical energy to the first generator motor 21a and second generator motor 21b via transformers, converting it into mechanical energy. This mechanical energy is then converted into water potential energy by the first pump turbine 6a and second pump turbine 6b, pumping the water from the lower reservoir 9 into the upper reservoir 1. When the water level in the water-air co-containment chamber 10 drops to the minimum operating level, or the lower reservoir 9 drops to the dead water level, or the upper reservoir 1 rises to the normal storage level, or when the power system does not require energy storage, the system stops storing energy. The first pump turbine 6a, second pump turbine 6b, and air compressor 17 stop working, and the second air pipeline ball valve 12b and the first and second water inlet ball valves 5a and 5b are closed.

[0064] Based on the description and accompanying drawings of this invention, those skilled in the art can readily manufacture or use a constant-pressure compressed air energy storage system and method combined with pumped storage, and can achieve the positive effects described in this invention.

[0065] Unless otherwise specified, in this invention, terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe orientation or positional relationships in this invention are for illustrative purposes only and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood in conjunction with the accompanying drawings and according to the specific circumstances.

[0066] Unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A constant pressure compressed air energy storage system in combination with pumped storage, characterized in that: It includes a pumped-storage subsystem, a turbine expansion and power generation system, an air compression subsystem, and a water-air co-containment chamber constant-pressure subsystem; The constant pressure subsystem of the water-air co-containment chamber includes a water-air co-containment chamber (10), the upper layer of which is used to store high-pressure air and the lower layer is used to store water. The pumped storage subsystem is connected to the power grid system. The pumped storage subsystem includes an upper reservoir (1) that is higher than the water-air co-containment chamber (10) and a lower reservoir (9) that is lower than the upper reservoir (1) but higher than the water-air co-containment chamber (10). The pumped storage subsystem is configured such that when generating electricity, the pumped storage subsystem can generate electricity by utilizing the liquid level difference between the upper reservoir (1) and the lower reservoir (9). When storing energy, the pumped storage subsystem can use the electrical energy of the power grid system to pump water from the lower reservoir (9) into the upper reservoir (1). The turbine expansion power generation system is connected to the power grid system. The turbine expansion power generation system is connected to the upper layer of the water-air co-containment chamber (10). The turbine expansion power generation system is configured such that when generating electricity, the turbine expansion power generation system is driven by the high-pressure air in the upper layer of the water-air co-containment chamber (10) to convert mechanical energy into electrical energy and transmit it to the power grid system. The air compression subsystem is connected to the power grid system and the air compression subsystem is connected to the upper layer of the water-air co-containment chamber (10). The air compression subsystem is configured to: when storing energy, the air compression subsystem can use the power of the power grid system to convert outdoor air into high-pressure air and enter the water-air co-containment chamber (10) and pressurize water into the upper reservoir (1). The upper reservoir (1) is connected to the first water pump turbine (6a) through the main water intake tunnel (2) and the first water intake branch tunnel (4a). The upper reservoir (1) is connected to the second water pump turbine (6b) through the main water intake tunnel (2) and the second water intake branch tunnel (4b). The upper reservoir (1) is connected to the bottom of the water-air co-containment chamber through the main water intake tunnel (2) and the third water intake branch tunnel (4c). The first water pump turbine (6a) is connected to the lower reservoir (9) through the first tailrace branch tunnel (7a) and the tailrace main tunnel (8). The first pump turbine (6a) and the second pump turbine (6b) are connected to the first generator motor (21a) and the second generator motor (21b) respectively, and are connected to the power grid system through the outlet bus, transformer, and high-voltage cable; a first inlet ball valve (5a) is installed on the first water intake branch (4a) in front of the first pump turbine (6a), a second inlet ball valve (5b) is installed on the second water intake branch (4b) in front of the second pump turbine (6b), and a third inlet ball valve (5c) is installed on the third water intake branch (4c); The constant pressure subsystem of the water-air coexistence chamber also includes a third pressure transmitter (25c), a third temperature transmitter (23c), a safety valve (4), and a sprinkler (26) installed on the upper layer of the water-air coexistence chamber. The sprinkler (26) is connected to the main water intake tunnel (2) through a pressure reducing valve (27) and a water supply pipeline (29). The third pressure transmitter (25c) is used to monitor the air pressure on the upper layer of the water-air coexistence chamber (10) in real time. The third temperature transmitter (23c) is used to monitor the air temperature on the upper layer of the water-air coexistence chamber (10) in real time. The safety valve (24) is used to automatically release pressure when the air pressure on the upper layer of the water-air coexistence chamber (10) reaches the limit value. A third level transmitter (30c) is installed on the lower layer of the water-air co-containment chamber (10) to monitor the water level of the water-air co-containment chamber (10) in real time. The chamber body of the water-air co-containment chamber (10) includes a steel plate sealing layer (33) and a concrete lining (32) located outside the steel plate sealing layer (33). A water curtain (31) is formed between the steel plate sealing layer (33) and the concrete lining (32). The water curtain (31) is connected to the main water intake tunnel (2) through a ball valve (28) and a water supply pipe (29). A fourth pressure transmitter (25d) is installed above the water curtain (31) to monitor the pressure of the water curtain (31) in real time. The turbine expansion power generation system includes a first heat exchanger (13a), a turbine (16), and a gas storage tank (20) connected in sequence. The gas storage tank (20) is used to provide a constant gas source for the low-pressure gas users of the power station. The first heat exchanger (13a) is connected to the heat storage tank (15) through a first heat medium conveying pipeline (14a). The heat storage tank (15) is used to store the heat generated by the air compression subsystem during energy storage. A third generator motor (18) is also connected to the turbine (16). The third generator motor (18) is connected to the power grid system through an outlet bus, a transformer, and a high-voltage cable. When generating electricity, the turbine (16) expands to do work, and the third generator motor (18) rotates clockwise. The air compression subsystem includes a second heat exchanger (13b), an air compressor (17), and an air filter (19) connected in sequence. The second heat exchanger (13b) is connected to the heat storage tank (15) through a second heat medium conveying pipe (14b). The air compressor (17) can be used to provide air source for the medium-pressure gas users of the power station. The air compressor (17) is also connected to a third generator motor (18). When storing energy, the air compressor (17) compresses air, and the third generator motor (18) rotates counterclockwise.

2. The constant pressure compressed air energy storage system in combination with pumped storage according to claim 1, characterized in that: A first level transmitter (30a) is installed in the upper reservoir (1), a second level transmitter (30b) is installed in the lower reservoir, and a water hammer elimination tank (3) is installed on the main water intake tunnel (2); a first tailwater butterfly valve (22a) is installed on the first tailwater branch tunnel (7a) after the first water pump turbine (6a), and a second tailwater butterfly valve (22b) is installed on the second tailwater branch tunnel (7b) after the second water pump turbine (6b).

3. The constant pressure compressed air energy storage system in combination with pumped storage according to claim 1, characterized in that: The elevation of the water-air co-containment chamber is basically the same as that of the first water intake branch (4a), the second water intake branch (4b), the third water intake branch (4c), the first water pump turbine (6a), and the second water pump turbine (6b).

4. The constant pressure compressed air energy storage system in combination with pumped storage according to claim 1, characterized in that: One end of the first heat exchanger (13a) is connected to the upper layer of the water-gas co-containment chamber (10) via the second gas pipeline (11b) and the first gas pipeline (11a). The other end of the first heat exchanger (13a) is connected to the turbine (16) via the second gas pipeline (11b) with a first pressure transmitter (25a) and a first temperature transmitter (23a). A first gas pipeline ball valve (12a) is installed on the second gas pipeline (11b) between the first heat exchanger (13a) and the water-gas co-containment chamber (10). A third gas pipeline ball valve (12c) is installed on the second gas pipeline (11b) between the turbine (16) and the gas storage tank (20).

5. The constant pressure compressed air energy storage system in combination with pumped storage according to claim 4, characterized in that: One end of the second heat exchanger (13b) is connected to the upper layer of the water-air co-containment chamber (10) via the third gas pipeline (11c) and the first gas pipeline (11a). The other end of the second heat exchanger (13b) is connected to the third gas pipeline (11c) between the air compressor (17) and the second heat exchanger (13b) with a second pressure transmitter (25b) and a second temperature transmitter (23b). The third gas pipeline (11c) between the second heat exchanger (13b) and the water-air co-containment chamber (10) is connected to a second gas pipeline ball valve (12b).

6. A control method of the constant pressure compressed air energy storage system combined with pumped storage according to claim 5, characterized by, Includes the following steps: Before starting energy storage, close the first water inlet ball valve (5a), the second water inlet ball valve (5b), the first gas pipeline ball valve (12a), the second gas pipeline ball valve (12b), and the third gas pipeline ball valve (12c), and open the third water inlet ball valve (5c) and ball valve (28) to fill the water-air co-containment chamber (10) and the water curtain (31) with water. At the same time, open the second gas pipeline ball valve (12b), and the air compressor (17) starts to work. The air compressor (17) compresses the outdoor gas filtered by the air filter (19) into high-pressure air and injects it into the water-air co-containment chamber (10) so that the gas pressure inside the water-air co-containment chamber (10) is equal to the pressure formed by the height difference between the upper reservoir and the water-air co-containment chamber. At this time, the initial constant pressure system of the water-air co-containment chamber (10) is completed, the air compressor (17) stops working, and the ball valve (28) and the second gas pipeline ball valve (12b) are closed. When renewable energy generation decreases sharply or electricity demand increases, leading to insufficient power in the grid system, and it is necessary to operate in power generation mode, any one of the following three methods can be adopted according to actual needs: In the first method, the pumped storage subsystem generates electricity independently: the third inlet ball valve (5c) is closed, and the first inlet ball valve (5a) and the second inlet ball valve (5b) are opened. The water in the upper reservoir (1) flows to the lower reservoir (9). The first pump turbine (6a) and the second pump turbine (6b) operate in power generation mode, converting the potential energy of the upper reservoir (1) into mechanical energy, and then into electrical energy through the first generator motor (21a) and the second generator motor (21b), which is then transmitted to the power grid system via a transformer. At this time, the turbine (16), the air compressor (17), and the water-air co-containment chamber (10) do not work. When the upper reservoir (1) drops to the dead water level or the lower reservoir (9) rises to the normal storage level or the power system does not need to operate in power generation mode, the system stops generating electricity. In the second method, the turbine expansion subsystem generates electricity independently: the first inlet ball valve (5a), the second inlet ball valve (5b), and the second gas pipeline ball valve (12b) are closed, and the third inlet ball valve (5c) and the first gas pipeline ball valve (12a) are opened. The water in the upper reservoir (1) flows to the water-air co-containment chamber (10). The high-pressure air at the top of the water-air co-containment chamber (10) drives the turbine (16) to do work. The mechanical energy generated by the rotation of the turbine (16) is converted into electrical energy through the third generator motor (18) and transmitted to the power grid system through the transformer. At this time, the first water pump turbine (6a), the second water pump turbine (6b), and the air compressor (17) do not work. When the water level of the upper reservoir (1) drops to the dead water level or the water level of the water-air co-containment chamber (10) rises to the highest operating water level or the power system does not need to operate in the power generation mode, the system stops generating electricity. In the third method, the pumped storage subsystem and the turbine expansion subsystem generate electricity simultaneously: the second gas pipeline ball valve (12b) is closed, and the first inlet ball valve (5a), the second inlet ball valve (5b), and the third inlet ball valve (5c) are opened. The first pump turbine (6a) and the second pump turbine (6b) operate in power generation mode, converting the potential energy of the upper reservoir (1) into mechanical energy, and then into electrical energy through the first generator motor (21a) and the second generator motor (21b), which is then transmitted to the power grid system via a transformer. The water from the upper reservoir (1) flows to the lower reservoir (9). At the same time, the water-air co-containment chamber (10) and the turbine (16) are working. The water in the upper reservoir (1) flows to the water-air co-containment chamber (10). The high-pressure air at the top of the water-air co-containment chamber (10) drives the turbine (16) to do work. The mechanical energy generated by the rotation of the turbine (16) is converted into electrical energy through the third generator motor (18) and transmitted to the power grid system through the transformer. When the upper reservoir (1) drops to the dead water level or the lower reservoir (9) rises to the normal storage water level or the water level of the water-air co-containment chamber (10) rises to the highest operating water level or the power system does not need to be operated in the power generation mode, the system stops generating electricity. When renewable energy generation increases sharply or electricity demand decreases, resulting in a surplus of electricity in the power grid system, and energy storage is required, any one of the following three methods can be adopted according to actual needs: In the first method, the pumped storage subsystem stores energy independently: the third inlet ball valve (5c) is closed, and the first inlet ball valve (5a) and the second inlet ball valve (5b) are opened. The first pump turbine (6a) and the second pump turbine (6b) operate in pumping mode. The power grid system transmits electrical energy to the first generator motor (21a) and the second generator motor (21b) via transformers, converting it into mechanical energy. This mechanical energy is then converted into water potential energy through the first pump turbine (6a) and the second pump turbine (6b), pumping the water from the lower reservoir (9) into the upper reservoir (1). At this time, the turbine (16), the air compressor (17), and the water-air co-containment chamber (10) do not work. When the lower reservoir (9) drops to the dead water level or the upper reservoir (1) rises to the normal storage level or the power system does not need to operate in the energy storage mode, the system stops storing energy. The second method involves independent energy storage in the air compression subsystem: The first water inlet ball valve (5a), the second water inlet ball valve (5b), the first air delivery pipeline ball valve (12a), and the third air delivery pipeline ball valve (12c) are closed. The third water inlet ball valve (5c) and the second air delivery pipeline ball valve (12b) are opened. The power grid system transmits electrical energy to the air compressor (17) via a transformer. The air compressor (17) starts, converting the outdoor air filtered by the air filter (19) into high-pressure gaseous air, which is then forced into the water-air co-containment chamber (10). As the water level in the chamber (10) gradually decreases, the water flows through the third water intake branch (4c) into the main water intake tunnel (2) and into the upper reservoir (1). When the air compressor (17) and the water-air co-containment chamber (10) are working, they send the water pressure of the water-air co-containment chamber (10) to the upper reservoir. At this time, the first water pump turbine (6a) and the second water pump turbine (6b) are not working. When the water level in the water-air co-containment chamber (10) drops to the minimum operating water level or the upper reservoir (1) rises to the normal storage water level or the power system does not need to operate in the energy storage mode, the system stops storing energy. The third method involves simultaneous energy storage in both the pumped-storage subsystem and the air compression subsystem: The first gas pipeline ball valve (12a) and the third gas pipeline ball valve (12c) are closed, while the second gas pipeline ball valve (12b), the first water inlet ball valve (5a), the second water inlet ball valve (5b), and the third water inlet ball valve (5c) are opened. The power grid system transmits electrical energy to the air compressor (17) via a transformer. The air compressor (17) starts, converting outdoor air filtered by the air filter (19) into high-pressure gaseous air, which is then forced into the water-air co-containment chamber (10). The water level in the water-air co-containment chamber (10) gradually decreases, and the water flows into the main water diversion tunnel through the third water diversion branch tunnel (4c). (2) and flow into the upper reservoir (1); at the same time, the first water pump turbine (6a) and the second water pump turbine (6b) operate in pumping mode, and the power grid system transmits electrical energy to the first generator motor (21a) and the second generator motor (21b) through the transformer to convert it into mechanical energy, and then converts it into water potential energy through the first water pump turbine (6a) and the second water pump turbine (6b) to pump the water from the lower reservoir (9) into the upper reservoir (1); when the water level of the water-air co-containment chamber (10) drops to the minimum operating water level or the lower reservoir (9) drops to the dead water level or the upper reservoir (1) rises to the normal storage water level or the power system does not need to operate in the energy storage mode, the system stops energy storage.

Images