A multi-cavity circulating pumped storage system

Abstract

A multi-cavity circulating pumped storage system comprises an underground powerhouse and multiple caverns. The underground powerhouse includes water pumps and a main turbine. The multiple caverns consist of upper, middle, and lower caverns, each with its own upper, middle, and lower caverns, and equipped with turbines. The caverns are connected by guide tunnels containing water pipelines. The flow rate or velocity is controlled by ball valves. Furthermore, the fluids in the upper, middle, and lower caverns mutually replenish each other, forming a water source circulation. The middle and lower caverns generate electricity to meet the needs of nearby industries and residents, with excess power transmitted to the external power grid for storage. The underground powerhouse generates electricity to supply the generating units, with the remainder transmitted to the external power grid for storage. This achieves energy integration and rational resource allocation. The stored energy also provides a guarantee for power supply during emergencies or peak demand. The upper, middle, and lower caverns are flexibly arranged in layers, which can solve the electricity needs of residents or industries in stages, shortening the power transmission distance, improving power generation efficiency, and reducing transmission losses.

Description

Technical Field

[0001] This invention relates to the field of pumped storage power station system design technology, and in particular to a multi-cavity circulating pumped storage system. Background Technology

[0002] Pumped storage power generation, as an emerging renewable energy source, makes up for the power shortage in the power grid, but it generally suffers from problems such as low power generation efficiency and difficulties in power transmission and utilization. Therefore, it is necessary to design new pumped storage systems that can solve the problems of industrial and residential power consumption within the power generation area of ​​the plant, reduce power transmission distance, reduce power loss, and improve power generation and utilization efficiency.

[0003] In the prior art, patent application CN112523918A discloses a pumped-storage power generation system. This system can both generate electricity using water from the upper reservoir and pump water from the lower reservoir to the upper reservoir for energy storage using electricity from the grid, transforming the original single-function hydropower station system into a dual-function system capable of both power generation and energy storage. Another example is patent CN217999775U, which discloses a pumped-storage system using an underground cavern, including cavern components and power conversion components. The cavern components include a first cavern unit, a second cavern unit, a third cavern unit, and a connecting tunnel. The first cavern unit is located within a mountain, and the second cavern unit is located underground, with a height difference between them. The connecting tunnel is fluidly connected to both the first and second cavern units. The power conversion components include a water pump, a water turbine, and a substation. Both the water pump and the water turbine are electrically connected to the substation. The water pump is used to transfer fluid from the second cavern unit to the first cavern unit through a connecting tunnel, and the water turbine is used to generate electricity.

[0004] Existing pumped storage technology consists of an upper reservoir and a lower reservoir, with the power plant located between the upper and lower reservoirs. The upper reservoir is generally located on the top of a mountain, while the lower reservoir is usually built using an existing reservoir. During power generation and transmission, there are problems such as excessively long transmission pipelines, excessive power loss, and reduced availability. Therefore, it is necessary to redesign the pumped storage system in a new way, based on the principles of convenience, speed, efficiency, and low consumption, adapting to the terrain, and comprehensively arranging it to meet the electricity needs of residents or industries nearby. Summary of the Invention

[0005] The main objective of this invention is to propose a multi-cavity circulating pumped storage system to solve the aforementioned technical problems.

[0006] To achieve the above objectives, this invention proposes a multi-cavity circulating pumped storage system, comprising an upper cavern and an underground powerhouse. An upper cavern is housed within the upper cavern. A water pump and a main turbine are housed within the underground powerhouse. In terms of elevation, multiple intermediate caverns are located below the upper cavern, and multiple lower caverns are located below the intermediate caverns, with one intermediate cavern corresponding to one lower cavern. Each intermediate cavern houses a intermediate cavern and a turbine. Each lower cavern houses a lower cavern and a turbine. The upper cavern and the multiple intermediate caverns are connected via upper guide tunnels. An upper water supply pipe is installed within the upper guide tunnels to connect the upper cavern and the intermediate caverns. The turbines within the intermediate caverns are mounted on the upper water supply pipe. The central cavern is connected to the corresponding lower cavern via a central guide tunnel. A central water supply pipe is installed in the central guide tunnel to connect the central cavern and the lower cavern. The turbines in the lower caverns are mounted on the central water supply pipe. The underground powerhouse is connected to multiple lower caverns via lower guide tunnels, which contain lower water supply pipes and return pipes. The upper cavern is connected to the underground powerhouse via a main tunnel, which contains a main return pipe and a main water supply pipe. The lower cavern within the lower cavern is connected to the pumps in the underground powerhouse via the return pipe, and the pumps are connected to the upper cavern via the main return pipe. The upper cavern receives water from the main water supply pipe to the main turbines. The lower water supply pipe is used to transport the water flowing through the main turbines to the lower caverns.

[0007] Preferably, ball valves are installed on the upper water supply pipe, the middle water supply pipe, and the lower water supply pipe.

[0008] Preferably, a first substation is set up in the central cavern to supply electricity to the central residents or industries by using the power generated by the turbines in the central cavern; the power generated by the turbines in the central cavern is also fed into the external power grid for storage.

[0009] Preferably, a second substation is provided at the lower cavern to supply electricity to the residents or industries in the lower cavern by the power generated by the turbine in the lower cavern; the power generated by the turbine in the lower cavern is also fed into the external power grid for storage.

[0010] Preferably, a third substation is set up at the underground powerhouse to supply the power generated by the main turbine to the underground powerhouse, and the power generated by the main turbine is also fed into the external power grid for storage.

[0011] Preferably, there are two central chambers, namely a central left chamber and a central right chamber; there are two lower chambers, namely a lower left chamber and a lower right chamber; a central left storage chamber is provided in the central left chamber, and a central right storage chamber is provided in the central right chamber; a lower left storage chamber is provided in the lower left chamber, and a lower right storage chamber is provided in the lower right chamber; the capacity of the upper storage chamber is equal to the sum of the capacities of the lower left and lower right storage chambers.

[0012] Preferably, the dynamic flow storage capacities of the upper cavern, the middle left cavern, the middle right cavern, the lower left cavern, and the lower right cavern are W1, W2, W3, W4, and W5, respectively, where W2=W3=W4=W5, and W1=2W2=2W3=2W4=2W5.

[0013] Preferably, the upper cavern is connected to the middle left cavern via a first water supply pipe; the upper cavern is connected to the middle right cavern via a second water supply pipe; the middle left cavern is connected to the lower left cavern via a third water supply pipe; the middle right cavern is connected to the lower right cavern via a fourth water supply pipe; the lower left cavern is connected to the water pump in the underground powerhouse via a first return water pipe; and the lower right cavern is connected to the water pump in the underground powerhouse via a second return water pipe.

[0014] Preferably, the height difference between the upper chamber and the middle chamber is ≥200m; the height difference between the middle chamber and the lower chamber is ≥200m.

[0015] Preferably, the horizontal distance between two adjacent middle caverns is ≥5 times the cavern width; the horizontal distance between the lower cavern and the underground powerhouse is ≥5 times the cavern width; and the horizontal distance between two adjacent lower caverns is ≥5 times the cavern width.

[0016] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0017] (1) The pumped storage system provided by the present invention consists of multiple caverns, which are arranged in upper, middle and lower positions, and can solve the electricity needs of residents or industries in layers and zones, so as to achieve convenient and efficient power supply.

[0018] (2) The pumped storage system provided by the present invention reduces the power transmission distance, improves the power generation and utilization efficiency, and reduces energy loss due to the layered arrangement of the pumped storage system. Furthermore, the design is simple, the construction is relatively conventional, and there is no need to equip a large-scale professional team.

[0019] (3) The pumped storage system provided by the present invention is flexible in layout. The middle layer left and right caverns and the lower layer left and right caverns can be arranged according to the actual situation of the mountain. They do not need to be symmetrical. It is only necessary to ensure that there is a certain height difference.

[0020] (4) The pumped storage system provided by the present invention is a closed loop from power generation to power consumption, and the water is also a closed loop from pump to power generation, realizing resource integration and comprehensive utilization. The ball valve setting realizes effective control of water volume and water speed, while the substation setting ensures the effective utilization of electrical energy.

[0021] (5) The multi-cavity circulating pumped storage system provided by the present invention consists of an underground powerhouse and multiple caverns. The underground powerhouse includes a water pump and a main turbine. The multiple caverns consist of upper, middle and lower caverns. The upper, middle and lower caverns are respectively arranged with upper, middle and lower caverns and equipped with turbines. The caverns are connected by guide tunnels. Water pipelines are installed in the guide tunnels. The flow rate or velocity is controlled by ball valves. In addition, the fluids in the upper, middle and lower caverns complement each other to form a water source circulation. The middle and lower caverns generate electricity to solve the electricity needs of nearby industries and residents. The excess is transmitted to the external power grid for storage. The underground powerhouse generates electricity to supply the generator set, and the remainder is transmitted to the external power grid for storage. This forms energy integration and rational allocation of resources. Its stored electricity also provides a guarantee for emergency or peak electricity use. The upper, middle and lower caverns are arranged in a flexible manner in layers, which can solve the electricity needs of residents or industries in layers, shorten the transmission distance, improve the power generation efficiency, and reduce transmission losses. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the overall layout of a multi-cavity circulating pumped storage system.

[0024] Figure 2 This is a schematic diagram of the structural connection of a multi-cavity circulating pumped storage system.

[0025] Figure 3 This is a schematic diagram of the power generation process of a multi-cavity circulating pumped storage system.

[0026] Figure 4 This is a flowchart illustrating the implementation method of a multi-cavity circulating pumped storage system.

[0027] Explanation of map symbols: 1. Upper cavern; 2. Middle left cavern; 3. Middle right cavern; 4. Lower left cavern; 5. Lower right cavern; 6. Underground powerhouse; 7. Water pump; 8. Main turbine; 9. Upper reservoir; 10. Middle left cavern; 11. Middle right cavern; 12. Lower left cavern; 13. Lower right cavern; 14. First pilot tunnel; 15. Second pilot tunnel; 16. Third pilot tunnel; 17. Fourth pilot tunnel; 18. Fifth pilot tunnel; 19. Sixth pilot tunnel; 20. Main tunnel; 21. 22. First water supply pipe; 23. Second water supply pipe; 24. Third water supply pipe; 25. Fourth water supply pipe; 26. Fifth water supply pipe; 27. Sixth water supply pipe; 28. First return water pipe; 29. ​​Second return water pipe; 30. Main return pipe; 31. Main water supply pipe; 32. Ball valve; 33. Third substation; 34. First energy consumption; 35. Second energy consumption; 36. Third energy consumption; 37. Fourth energy consumption; 38. Fifth energy consumption; 39. Residual energy; 40. First substation; 41. Second substation. Detailed Implementation

[0028] To make this invention more intuitive and easier to understand, and to enable those skilled in the art to better understand and master its technical solutions, the following is based on... Figures 1 to 4 The present invention will be described in detail below.

[0029] It is worth noting that the provided examples are merely preferred examples of the present invention, and the accompanying drawings are for illustrative purposes only and do not represent any defects or limitations. The dimensions of the drawings may be reduced or increased and do not represent the actual dimensions.

[0030] Furthermore, the terms "first" and "second" appearing in the accompanying drawings are for ease of naming and differentiation and do not represent any special meaning. The letters "A" and "W" represent numerical characteristics in a certain state and do not imply any limitation on the scope of application of this invention.

[0031] Combination Figures 1 to 3As shown, a multi-cavity circulating pumped storage system includes an upper cavern 1 and an underground powerhouse 6. An upper cavern 9 is located within the upper cavern 1. A water pump 7 and a main turbine 8 are located within the underground powerhouse 6. In the elevation direction, multiple intermediate caverns are located below the upper cavern 1, and multiple lower caverns are located below the intermediate caverns, with one intermediate cavern corresponding to one lower cavern. Each intermediate cavern contains an intermediate cavern and a turbine; each lower cavern contains a lower cavern and a turbine. The upper cavern 1 and the multiple intermediate caverns are connected by upper guide tunnels. Upper water pipes are installed within the upper guide tunnels to connect the upper cavern 9 and the intermediate caverns. The turbines within the intermediate caverns are mounted on the upper water pipes. Each intermediate cavern is connected to its corresponding lower cavern. The caverns are connected by a central guide tunnel, within which a central water pipe connects the central cavern and the lower cavern. The turbine in the lower cavern is mounted on the central water pipe. The underground powerhouse 6 is connected to multiple lower caverns via lower guide tunnels, within which lower water pipes and return pipes are installed. The upper cavern 1 is connected to the underground powerhouse 6 via a main tunnel 20, within which a main return pipe 29 and a main water pipe 30 are installed. The lower cavern within the lower cavern is connected to a water pump 7 in the underground powerhouse 6 via a return pipe. The water pump 7 is connected to the upper cavern 9 via the main return pipe 29. The upper cavern 9 receives water from the main water pipe 30 and directs it to the main turbine 8. The lower water pipe transports the water flowing through the main turbine 8 to the lower cavern. Ball valves 31 are installed on the upper, central, and lower water pipes. A first substation 39 is located in the central cavern to supply electricity to residents or industries within the central cavern by powering the turbines there. The electricity generated by the turbines in the central cavern is also stored in the external power grid. A second substation 40 is located in the lower cavern to supply electricity to residents or industries in the lower cavern by powering the turbines there. The electricity generated by the turbines in the lower cavern is also stored in the external power grid. A third substation 32 is located in the underground powerhouse 6 to supply electricity to the underground powerhouse 6 from the main turbine 8. The electricity generated by the main turbine 8 is also stored in the external power grid.

[0032] Specifically, in this embodiment, there are two central caverns, namely a central left cavern 2 and a central right cavern 3; there are two lower caverns, namely a lower left cavern 4 and a lower right cavern 5; a central left storage chamber 10 is provided in the central left cavern 2, and a central right storage chamber 11 is provided in the central right cavern 3; a lower left storage chamber 12 is provided in the lower left cavern 4, and a lower right storage chamber 13 is provided in the lower right cavern 5. The upper guide tunnel includes the first guide tunnel 14 and the second guide tunnel 15, and the upper water supply pipe includes the first water supply pipe 21 and the second water supply pipe 22; the middle guide tunnel includes the third guide tunnel 16 and the fourth guide tunnel 17, and the middle water supply pipe includes the third water supply pipe 23 and the fourth water supply pipe 24; the lower guide tunnel includes the fifth guide tunnel 18 and the sixth guide tunnel 19; the lower water supply pipe includes the fifth water supply pipe 25 and the sixth water supply pipe 26, and the return water pipe includes the first return water pipe 27 and the second return water pipe 28. The middle left cavern 10 is connected to the upper cavern 1 through the first guide tunnel 14; the middle right cavern 3 is connected to the upper cavern 1 through the second guide tunnel 15; the lower left cavern 4 is connected to the middle left cavern 10 through the third guide tunnel 16; the lower right cavern 5 is connected to the middle right cavern 3 through the fourth guide tunnel 17; the lower left cavern 4 is connected to the underground powerhouse 6 through the fifth guide tunnel 18; and the lower right cavern 5 is connected to the underground powerhouse 6 through the sixth guide tunnel 19.

[0033] Furthermore, combined Figure 1 , Figure 2 As shown, in this embodiment, the first guide tunnel 14, the second guide tunnel 15, the third guide tunnel 16, and the fourth guide tunnel 17 are respectively equipped with a first water supply pipe 21, a second water supply pipe 22, a third water supply pipe 23, and a fourth water supply pipe 24. The upper cavern 9 is connected to the middle left cavern 10 through the first water supply pipe 21; the upper cavern 9 is connected to the middle right cavern 11 through the second water supply pipe 22; the middle left cavern 10 is connected to the lower left cavern 12 through the third water supply pipe 23; the middle right cavern 11 is connected to the lower right cavern 13 through the fourth water supply pipe 24; the lower left cavern 12 is connected to the water pump 7 in the underground powerhouse 6 through the first return water pipe 27; and the lower right cavern 13 is connected to the water pump 7 in the underground powerhouse 6 through the second return water pipe 28. The water turbine in the middle left chamber 2 is connected to the first water supply pipe 21, the water turbine in the middle right chamber 3 is connected to the second water supply pipe 22, the water turbine in the lower left chamber 4 is connected to the third water supply pipe 23, the water turbine in the lower right chamber 5 is connected to the fourth water supply pipe 24, the first return water pipe 27 and the fifth water supply pipe 25 are located in the fifth guide tunnel 18, and the second return water pipe 28 and the sixth water supply pipe 26 are located in the sixth guide tunnel 19.

[0034] The main turbine 8 is connected to the lower left cavern 12 and the lower right cavern 13 through the fifth water supply pipe 25 and the sixth water supply pipe 26, respectively, to transport the water flowing through the main turbine 8 to the lower left cavern 12 and the lower right cavern 13, respectively. Its return fluid passes through the first return water pipe 27 and the second return water pipe 28 and then through the water pump 7 to form the bottom fluid circulation.

[0035] The fluid in the upper cavern 9 comes from the pumping volume of the lower left cavern 12 and the lower right cavern 13. Therefore, the capacity of the upper cavern 9 is equal to the sum of the capacities of the lower left cavern 12 and the lower right cavern 13.

[0036] The liquid in the upper cavern 9 is used to generate electricity for the main turbine 8 in the underground powerhouse 6. A portion of the liquid flows into the middle left cavern 10 and the middle right cavern 11 through the first water supply pipe 21 and the second water supply pipe 22, respectively. The structural sequence of the middle left cavern 2 is: first water supply pipe 21 → turbine in the middle left cavern 10 → middle left cavern 10. The structural sequence of the middle right cavern 3 is: second water supply pipe 22 → turbine in the middle right cavern 11 → middle right cavern 11.

[0037] The fluids in the lower left cavern 12 and the lower right cavern 13 originate from the middle left cavern 10 and the middle right cavern 11, respectively. The structural sequence of the lower left cavern 4 is: the third water supply pipe 23 → the water turbine in the lower left cavern 12 → the lower left cavern 12; the structural sequence of the lower left cavern 5 is: the fourth water supply pipe 24 → the water turbine in the lower right cavern 13 → the lower right cavern 13.

[0038] Based on the above structure, the multi-cavity circulating pumped storage system provided by this invention has a multi-cavity circulating power generation system divided into water source circulation and power generation circulation. The left water source circulation is as follows: upper cavity 9 → middle left cavity 10 → lower left cavity 12 → upper cavity 9; the right water source circulation is as follows: upper cavity 9 → middle right cavity 11 → lower right cavity 13 → upper cavity 9.

[0039] In addition to meeting the size requirements of the upper chamber 9 and ball valve 31, the minimum chamber size of the upper chamber 1 also reserves space for frequency and pressure regulation maintenance.

[0040] The minimum chamber size of the left central chamber 2 not only meets the size requirements of the turbine room and the left central chamber 10, but also reserves space for frequency and pressure regulation maintenance.

[0041] In addition to meeting the size requirements of the turbine room and the central right cavern 11, the minimum cavern size of the central right cavern 3 must also reserve space for frequency regulation and pressure regulation maintenance.

[0042] The minimum chamber size of the lower left chamber 4 not only meets the size requirements of the turbine room and the lower left reservoir 12, but also reserves space for frequency and pressure regulation maintenance.

[0043] The minimum chamber size of the lower right chamber 5 not only meets the size requirements of the turbine room and the lower right cavern 13, but also reserves space for frequency and pressure regulation maintenance.

[0044] In addition to meeting the size requirements of the water pump 7 and the main turbine 8, the minimum chamber size of the underground powerhouse 6 also provides space for frequency and pressure regulation maintenance.

[0045] The storage capacities of the middle left cavern 10 and the middle right cavern 11 should be controlled to be the same; the storage capacities of the lower left cavern 12 and the lower right cavern 13 should also be controlled to be the same. Specifically, the dynamic flow storage capacities of the upper cavern 9, the middle left cavern 10, the middle right cavern 11, the lower left cavern 12, and the lower right cavern 13 are W1, W2, W3, W4, and W5, respectively, where W2=W3=W4=W5, and W1=2W2=2W3=2W4=2W5.

[0046] The electricity generated by the turbines in the central left chamber 2 and central right chamber 3 is partly supplied to the central residents or industries via the first substation 39, with a power supply amount of A1+A2, and the other part is stored through the external power grid. The electricity generated by the turbines in the lower left chamber 4 and lower right chamber 5 is partly supplied to the lower two sides to the residents or industries via the second substation 40, with a power supply amount of A3+A4, and the other part is stored through the external power grid. The underground powerhouse 6 requires A5 in electrical energy. The external power grid stores A0 in electrical energy.

[0047] The total power generation of the entire system in one cycle is:

[0048]

[0049] In formula (1): A is the total electrical energy generated by the system; A0 is the total electrical energy stored; A1 is the total electricity consumption of residents or industries in the middle left; A2 is the total electricity consumption of residents or industries in the middle right; A3 is the total electricity consumption of residents or industries in the lower left; A4 is the total electricity consumption of residents or industries in the lower left; A5 is the electricity consumption of the underground plant.

[0050] The total energy consumption of the entire system in one cycle is:

[0051]

[0052] In formula (2): This represents the total electrical energy consumed by the system.

[0053] The overall system energy consumption rate is:

[0054]

[0055] In equation (3): P is the energy consumption rate of the entire system.

[0056] The overall system energy storage rate is:

[0057]

[0058] In equation (4): Q is the energy storage rate of the entire system.

[0059] The implementation method of the above-mentioned multi-cavity circulating pumped storage system includes the following steps:

[0060] S1. Construct an upper cavern 1, a middle left cavern 2, a middle right cavern 3, a lower left cavern 4, and a lower right cavern 5, respectively, and provide upper storage tanks 9, middle left caverns 10, middle right caverns 11, lower left caverns 12, and lower right caverns 13, respectively. Among them, middle left caverns 2, middle right caverns 3, lower left caverns 4, and lower right caverns 5 are equipped with water turbines for power generation.

[0061] S2. Excavate the connecting tunnels between the upper cavern 1, the middle left cavern 2, the middle right cavern 3, the lower left cavern 4, and the lower right cavern 5 respectively, namely, excavate the first guide tunnel 14, the second guide tunnel 15, the third guide tunnel 16, and the fourth guide tunnel 17.

[0062] S3. An underground powerhouse 6 is excavated between the lower left cavern 4 and the lower right cavern 5, equipped with a water pump 7 for water pumping and a main turbine 8 for power generation.

[0063] S4. Excavate the connecting tunnels connecting the underground powerhouse 6 and the upper cavern 1, namely, excavate the fifth pilot tunnel 18, the sixth pilot tunnel 19, and the main tunnel 20.

[0064] S5. Connect the power transmission lines and transformer lines of the middle left cavern 2, middle right cavern 3, lower left cavern 4, lower right cavern 5 and underground powerhouse 6 respectively;

[0065] S6. Using off-peak electricity, the fluid in the lower left cavern 12 and the lower right cavern 13 is pumped into the upper cavern 1 through the main return pipe 29 via the water pump 7. Part of the fluid flows into the main turbine 8 of the underground powerhouse 6 through the main water supply pipe 30 to generate electricity. Part of the electricity is input into the external power grid for storage through the substation 32. Part of the water supply is circulated by the water pump 7. The water in the underground powerhouse 6 is discharged into the lower left cavern 12 and the lower right cavern 13 through the fifth water supply pipe 25 and the sixth water supply pipe 26, respectively.

[0066] S7. A portion of the fluid from the upper cavern 1 is introduced into the middle left cavern 10 and the middle right cavern 11 through the first water supply pipe 21 and the second water supply pipe 22, respectively. The fluid is then used to generate electricity through the turbines in the middle left cavern 2 and the middle right cavern 3. Part of the electricity is then used to supply power to residential or industrial areas through the first substation 39. The other portion is transmitted to the external power grid for storage by the third substation 32 for use during special periods or emergencies.

[0067] 8. The fluids in the middle left cavern 10 and the middle right cavern 11 are introduced into the lower left cavern 12 and the lower right cavern 13 respectively through the third water supply pipe 23 and the fourth water supply pipe 24. The fluids are then used to generate electricity through the turbines in the lower left cavern 4 and the lower right cavern 5. Part of the electricity is used to supply power to residential or industrial areas through the second substation 40. The other part is transmitted to the external power grid for storage after passing through the third substation 32, for use during special periods or emergencies.

[0068] Furthermore, a closed loop is completed through steps S1 to S8, and the water volume between each cavern is controlled by the ball valve 31 to form a dynamic fluid balance between the upper cavern 9, the middle left cavern 10, the middle right cavern 11, the lower left cavern 12, and the lower right cavern 13.

[0069] Furthermore, during the excavation of the upper cavern 1, the middle left cavern 2, the middle right cavern 3, the lower left cavern 4, the lower right cavern 5, and the underground powerhouse 6, simultaneous excavation and support should be carried out to ensure construction and subsequent operation safety.

[0070] To ensure construction safety and the efficiency of water storage and power generation in the cavern, the elevation difference between the upper cavern 1 and the middle cavern must be ≥200m; the elevation difference between the middle cavern and the lower cavern must also be ≥200m. Specifically, the middle left cavern 2 and the middle right cavern 3 may be at the same or different elevations, but the elevation difference H1 between the upper cavern 1 and the middle left cavern 2 must be ≥200m, and the elevation difference H2 between the upper cavern 1 and the middle right cavern 3 must be ≥200m. The elevation difference H3 between the middle left cavern 2 and the lower left cavern 4 must be ≥200m, and the elevation difference H4 between the middle right cavern 3 and the lower right cavern 5 must be ≥200m.

[0071] The shapes of Upper Cavern 1, Middle Left Cavern 2, Middle Right Cavern 3, Lower Left Cavern 4, and Lower Right Cavern 5, as well as the shapes of Upper Cavern 9, Middle Left Cavern 10, Middle Right Cavern 11, Lower Left Cavern 12, and Lower Right Cavern 13, are not required and can be determined according to geological conditions and actual requirements, and can be adapted to local conditions.

[0072] To ensure the safety of cavern construction, the horizontal distance between two adjacent middle caverns shall be ≥5 times the cavern width; the horizontal distance between the lower cavern and the underground powerhouse 6 shall be ≥5 times the cavern width; and the horizontal distance between two adjacent lower caverns shall be ≥5 times the cavern width. Specifically, the horizontal distance L2 between the middle left cavern 2 and the middle right cavern 3 shall be ≥5 times the cavern width; the horizontal distance L1 between the lower left cavern 4 and the underground powerhouse 6 shall be ≥5 times the cavern width; the horizontal distance L3 between the lower right cavern 5 and the underground powerhouse 6 shall be ≥5 times the cavern width; and the horizontal distance L between the lower left cavern 4 and the lower right cavern 5 shall be ≥10 times the cavern width.

[0073] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A multi-cavity circulating pumped storage system, comprising an upper cavern (1) and an underground powerhouse (6), wherein an upper cavern (9) is provided in the upper cavern (1); and a water pump (7) and a main turbine (8) are provided in the underground powerhouse (6), characterized in that: In terms of elevation, multiple intermediate caverns are set below the upper cavern (1), and multiple lower caverns are set below the intermediate caverns. One intermediate cavern corresponds to one lower cavern. Each intermediate cavern contains an intermediate cavern and a water turbine. Each lower cavern contains a lower cavern and a water turbine. The upper cavern (1) is connected to multiple middle caverns through upper guide tunnels. An upper water supply pipe is installed in the upper guide tunnel to connect the upper cavern (9) and the middle caverns. The water turbine in the middle cavern is installed on the upper water supply pipe. Each central cavern is connected to the corresponding lower cavern via a central guide tunnel. A central water supply pipe is installed in the central guide tunnel to connect the central cavern and the lower cavern. The water turbine in the lower cavern is installed on the central water supply pipe. The underground powerhouse (6) is connected to multiple lower caverns via lower guide tunnels, in which lower water supply pipes and return pipes are installed; the upper cavern (1) is connected to the underground powerhouse (6) via a main tunnel (20), in which a main return pipe (29) and a main water supply pipe (30) are installed; the lower cavern within the lower cavern is connected to the water pump (7) in the underground powerhouse (6) via the return pipe, and the water pump (7) is connected to the upper cavern (9) via the main return pipe (29); the upper cavern (9) is diverted to the main turbine (8) via the main water supply pipe (30); the lower water supply pipe is used to transport the water flowing through the main turbine (8) to the lower cavern; The number of the middle caverns is two, namely the middle left cavern (2) and the middle right cavern (3); the number of the lower caverns is two, namely the lower left cavern (4) and the lower right cavern (5); a middle left cavern storage (10) is set in the middle left cavern (2), and a middle right cavern storage (11) is set in the middle right cavern (3); a lower left cavern storage (12) is set in the lower left cavern (4), and a lower right cavern storage (13) is set in the lower right cavern (5); the storage capacity of the upper cavern storage (9) is equal to the sum of the storage capacity of the lower left cavern storage (12) and the storage capacity of the lower right cavern storage (13); The dynamic flow storage capacities of the upper cavern (9), the middle left cavern (10), the middle right cavern (11), the lower left cavern (12), and the lower right cavern (13) are W1, W2, W3, W4, and W5, respectively, where W2=W3=W4=W5, and W1=2W2=2W3=2W4=2W5; The height difference between the upper chamber (1) and the middle chamber is ≥200m; the height difference between the middle chamber and the lower chamber is ≥200m; The horizontal distance between two adjacent middle caverns is ≥5 times the cavern width; the horizontal distance between the lower cavern and the underground powerhouse (6) is ≥5 times the cavern width; the horizontal distance between two adjacent lower caverns is ≥5 times the cavern width; A first substation (39) is set up in the central cavern to supply electricity to the residents or industries in the central cavern by the power generated by the turbines in the central cavern; the power generated by the turbines in the central cavern is also fed into the external power grid for storage. A second substation (40) is set up in the lower cavern to supply electricity to the residents or industries in the lower cavern by the power generated by the turbine in the lower cavern; the power generated by the turbine in the lower cavern is also fed into the external power grid for storage. A third substation (32) is set up in the underground powerhouse (6) to supply the power generated by the main turbine (8) to the underground powerhouse (6). The power generated by the main turbine (8) is also input into the external power grid for storage. The total power generation of the entire system in one cycle is: ； The total energy consumption of the entire system in one cycle is: ； The overall system energy consumption rate is: ； The overall system energy storage rate is: ； In the formula: A is the total electrical energy generated by the system; A0 is the total electrical energy stored; A1 is the total electricity consumption of residents or industries in the middle left; A2 is the total electricity consumption of residents or industries in the middle right; A3 is the total electricity consumption of residents or industries in the lower left; A4 is the total electricity consumption of residents or industries in the lower left; A5 is the electricity consumption of the underground plant. P represents the total electrical energy consumed by the system; Q represents the energy consumption rate of the entire system; and Q represents the energy storage rate of the entire system.

2. The multi-cavity circulating pumped storage system as described in claim 1, characterized in that: Ball valves (31) are installed on the upper water supply pipe, the middle water supply pipe, and the lower water supply pipe.

3. The multi-cavity circulating pumped storage system as described in claim 1, characterized in that: The upper cavern (9) and the middle left cavern (10) are connected by the first water supply pipe (21); The upper cavern (9) and the middle right cavern (11) are connected by the second water supply pipe (22); The middle left cavern (10) and the lower left cavern (12) are connected by a third water supply pipe (23); The middle right cavern (11) and the lower right cavern (13) are connected by the fourth water supply pipe (24); The lower left tunnel (12) is connected to the water pump (7) in the underground plant (6) through the first return water pipe (27); The lower right cavern (13) is connected to the water pump (7) in the underground plant (6) via the second return water pipe (28).

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