Multistage pumped storage system and method

Abstract

The invention discloses a multistage pumped storage system and method.The multistage pumped storage system comprises an upper reservoir, a lower reservoir, a gas production device, a water pressing device and a multistage energy storage reservoir, open channels are formed in the two sides of the upper reservoir, the open channels are communicated with a forebay, the gas production device is arranged in the lower reservoir, and the water pressing device is arranged in the forebay; the multi-stage energy storage reservoir is built on mountains on the two sides of the upper reservoir and / or the lower reservoir and communicated with the water pressing device, the open channel is communicated with the gas production device through a plurality of drainage pipes, the gas production device is communicated with the water pressing device, and the forebay is communicated with the water pressing device. Water is discharged from the upper reservoir open channel and enters the gas production device to generate compressed air, the compressed air enters the water pressing device after being generated, the compressed air is released and expands, water flowing into the water pressing device from the front reservoir is pressed out and lifted to the multi-stage energy storage reservoir at the corresponding height, and water pumping energy storage is conducted. The energy consumption can be reduced, the energy utilization rate is higher, and the cost is lower.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and in particular to a multi-stage pumped storage system and method. Background Art

[0002] Energy is the driving force for social development. As energy and environmental issues become increasingly prominent, renewable energy such as wind and solar energy have received more and more attention. However, the volatility and randomness of renewable energy and the insufficient peak-shaving capacity of existing power grids have brought huge challenges to the development of renewable energy.

[0003] As a transition system between power plants and power grids, energy storage systems can effectively solve the problem of renewable energy grid connection. Among the existing energy storage systems, pumped storage has been widely used. Traditional pumped storage uses the electrical energy generated during low power load to convert it into mechanical energy to pump water to a high-level reservoir, and then releases water to the lower reservoir for power generation during peak power load periods. The energy conversion process when pumping water is as follows: the gravitational potential energy of water is converted into kinetic energy, kinetic energy is converted into mechanical energy, and mechanical energy is converted into electrical energy. The electrical energy is then converted into mechanical energy of a water pump for pumping water. The energy conversion rate is low, and new pumping stations need to be built, which is costly. At the same time, when the energy storage reservoir is released to release energy, multiple power stations need to be built to generate electricity, further increasing costs. Summary of the invention

[0004] The main purpose of the present invention is to overcome the defects of the above-mentioned background technology and provide a multi-stage pumped storage system and method.

[0005] To achieve the above-mentioned purpose, the multi-stage pumped storage system proposed in the present invention includes an upper reservoir, a lower reservoir, a gas producing device, a water pressurizing device, and a multi-stage energy storage reservoir. Open channels are opened on both sides of the upper reservoir, and the open channels are connected to a forebay. The gas producing device is arranged in the lower reservoir. The multi-stage energy storage reservoirs are built on the mountains on both sides of the upper reservoir and / or the lower reservoir and are connected to the water pressurizing device. The open channels are connected to the gas producing device through multiple drainage pipes, the gas producing device is connected to the water pressurizing device, and the forebay is connected to the water pressurizing device. The water head of the upper reservoir enters the gas producing device to generate compressed air, and then enters the water pressurizing device. The water flowing from the forebay into the water pressurizing device is lifted to the multi-stage energy storage reservoirs for pumped storage. There is no need to build new pumps, and the energy utilization rate is high and the cost is low.

[0006] Furthermore, the gas production device includes a first gas production tank and a gas storage tank, the first gas production tank is respectively provided with a first water inlet, a first air supply port, a first air outlet and a first water inlet and outlet, a plurality of the drainage pipes are connected to the first water inlet, the first air outlet is connected to the gas storage tank, the first air supply port is connected to the external atmosphere, the first water inlet and outlet are connected to the lower reservoir, and valves are respectively provided on the drainage pipe, the first air supply port, the first air outlet and the pipes connected to the first water inlet and outlet. The water in the open channel is introduced into the first gas production tank through the drainage pipe, and the air in the first gas production tank is compressed to generate compressed air, and the generated compressed air enters the gas storage tank for standby use.

[0007] Furthermore, the water pressure device includes several groups of water pressure tanks, gas delivery columns and water delivery columns, the air outlet of the gas storage tank is connected to the gas delivery column, the multiple energy storage reservoirs are connected to the water delivery columns respectively, several groups of water pressure tanks are longitudinally arranged between the gas delivery column and the water delivery column and correspond to the multiple energy storage reservoirs, the front pool is connected to the water delivery column and the water inlet of the water pressure tank at the bottom, the water outlet of the lower water pressure tank is divided into two paths, one is connected to the water inlet of the upper water pressure tank, and the other is connected to the water delivery column, the air inlet of the water tank is connected to the gas delivery column, the valves are respectively provided on the pipelines connecting the multiple energy storage reservoirs and the water delivery column, the water pressure tank and the water delivery column, the water pressure tank and the gas delivery column, and the water outlet of the lower water pressure tank and the water inlet of the upper water pressure tank, the water pressure tank is provided with an air release port, and the valve is provided at the air release port. By setting up multiple groups of water pressure tanks to carry out relay water pressure lifting, water can be pumped to a higher height for energy storage.

[0008] Furthermore, the gas production device also includes a second gas production tank, on which a second water inlet, a second air supply port, a second air outlet and a second water inlet and outlet are respectively provided, the bottom end of the water delivery column is connected to the second water inlet, the second air outlet is connected to the gas storage tank, the second air supply port is connected to the external atmosphere, the second water inlet and outlet are connected to the lower reservoir, and valves are respectively provided on the pipelines connecting the water delivery column, the second air supply port, the second air outlet and the second water inlet and outlet, and the water head of the multi-stage energy storage reservoir enters the second gas production tank to generate compressed air, and then enters the first gas production tank through the gas storage tank, and presses out the water in the lower reservoir that flows into the first gas production tank through the first water inlet and outlet, returns to the open channel along the drainage pipe and finally flows back to the upper reservoir. When the multi-stage energy storage reservoir releases water and releases energy, compressed air is generated by the second gas production tank, and the generated compressed air is used to pump water from the lower reservoir to the upper reservoir, and the original generator set in the upper reservoir is used to generate electricity.

[0009] Furthermore, the multi-level energy storage reservoir is provided with at least six levels, the height difference between each level of the energy storage reservoir is marked as Hn, the height difference between the upper reservoir and the gas production device is marked as H, and H is greater than Hn. It is ensured that the water in the pressure water tank is lifted to a height that can enter the corresponding energy storage reservoir, and at the same time, it is ensured that the compressed air generated when the energy storage reservoir releases energy can pump the water in the lower reservoir to the upper reservoir for use.

[0010] The present invention also proposes a method for pumped storage using the above-mentioned multi-stage pumped storage system, comprising the following steps: S1. Select the upstream of the existing hydropower station dam as the upper reservoir and the downstream river channel as the lower reservoir, open channels are opened on both sides of the upper reservoir and / or the lower reservoir, the starting end of the open channel is connected to the upper reservoir, and the end of the open channel is connected to the front pool. S2. Set up a gas production device in the lower reservoir, and build a multi-stage energy storage reservoir higher than the water level of the upper reservoir according to the terrain on both sides of the upper reservoir and / or the lower reservoir. The multi-stage energy storage reservoir is arranged in a stepped manner, and the height difference between the arrangement positions of the multi-stage energy storage reservoirs is less than the height difference from the open channel to the gas production device; a plurality of drainage pipes are arranged along the open channel to the front pool, and the drainage pipes discharge water into the gas production device arranged in the lower reservoir, and the water head rushing down from the open channel enters the gas production device and is converted into compressed air. S3. Water delivery columns and gas delivery columns are provided on the mountain of the multi-stage energy storage reservoir. Each stage of the energy storage reservoir is connected to the water delivery column, and a water pressure device is provided between the water delivery column and the gas delivery column. The water pressure device at the bottom is connected to the front pool, the water outlet end of the water pressure device is connected to the water delivery column, and the air inlet end of the water pressure device is connected to the gas delivery column. S4, using the compressed air generated in step S2 to enter the water pressure device to release energy, and pressurize the water entering the water pressure device from the front pool to the corresponding multi-stage energy storage reservoir for pumped water storage; the gas production device includes a first gas production tank and a gas storage tank, the first gas production tank is connected to the gas storage tank, and multiple drainage pipes are connected to the first gas production tank. The water in the open channel rushes down along the drainage pipe into the first gas production tank, compressing the original air in the first gas production tank, and the generated compressed air enters the gas storage tank for storage. When the first gas production tank is full of water, the valve on the drainage pipe is closed, and part of the compressed air stored in the gas storage tank is released back to the first gas production tank, and the water in the first gas production tank is discharged to the lower reservoir along the first water inlet and outlet, and then the valve on the drainage pipe is opened to release water for the next compression, so as to continuously produce compressed air, and the generated compressed air is used for pumped water storage in step S4; the gas production device also includes a second gas production tank, and the second gas production tank is connected to the gas storage tank, and the bottom end of the water delivery column It is connected to the second gas production tank; when the multi-stage energy storage reservoir releases energy, water is released from the highest level energy storage reservoir one by one to release energy, and the water flows down along the water delivery column into the second gas production tank to compress the original air in the second gas production tank, and the generated compressed air enters the gas storage tank for storage, and then the generated compressed air is used to press the water entering the first gas production tank from the lower reservoir upward along the drainage pipe back into the open channel, and finally back to the upper reservoir, and the original power station of the upper reservoir is used to generate electricity; the water pressure device includes several groups of water pressure tanks The layout height of the water pressure tank corresponds to the layout height of the multi-stage energy-storage reservoir. The water inlet of the lowest water pressure tank is connected with the front pool. The water outlet of the water pressure tank is divided into two paths, one is connected with the water inlet of the upper water pressure tank, and the other is connected with the water delivery column. When the energy-storage reservoir corresponding to the water pressure tank is fully pumped or needs to be pumped to the corresponding height reservoir for water storage, the water pressed upward in the water pressure tank enters the water pressure tank of the upper level for relay water lifting, and the water is pumped to the energy-storage reservoir of the corresponding height for energy storage.

[0011] The beneficial effects of the present invention include: the present invention generates compressed air by releasing water from the open channel of the upper reservoir into the gas producing device. When releasing water, the gravitational potential energy of the water is converted into kinetic energy, which rushes into the gas producing device to compress the air originally in the gas producing device, and the water head is converted into compressed air. After the compressed air is generated, it enters the water pressurizing device. The compressed air is released and expanded, and the water flowing into the water pressurizing device from the front pool is pressed out, and lifted to a multi-stage energy storage reservoir of corresponding height for energy storage. Compared with traditional pumped storage, the present invention can reduce energy loss, have higher energy utilization rate, and does not require the construction of a new pumping station, and has lower cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is an overall schematic diagram of a multi-stage pumped storage system in an embodiment of the present invention.

[0013] Figure 2 Schematic diagram of the connection of the gas production device in the embodiment of the present invention.

[0014] Figure 3 Schematic diagram of the connection of the water pressure device in the embodiment of the present invention.

[0015] Figure 4 It is a flowchart of the multi-stage pumped storage method in an embodiment of the present invention.

[0016] Figure numerals: 1 upper reservoir; 101 open channel; 102 front pool; 103 drainage pipe; 2 lower reservoir; 3 gas production device; 301 first gas production tank; 3011 first water inlet; 3012 first air supply port; 3013 first air outlet; 3014 first water inlet and outlet 302 gas storage tank; 303 second gas production tank; 3031 second water inlet; 3032 second air supply port; 3033 second air outlet; 3034 second water inlet and outlet; 4 water pressure device; 401 water pressure tank; 4011 air release port; 402 gas transmission column; 403 water transmission column; 5 energy storage reservoir; 6 valve. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects to be solved by the embodiments of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for both fixing and circuit connection.

[0019] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0021] Embodiment 1:

[0022] See also Figures 1 to 3The multi-stage pumped storage system disclosed in the present invention comprises an upper reservoir 1, a lower reservoir 2, a gas producing device 3, a water pressurizing device 4, and a multi-stage energy storage reservoir 5. An open channel 101 is opened along the river banks on both sides of the upper reservoir 1. A forebay 102 is connected to the end of the open channel 101. The gas producing device 3 is arranged below the water surface of the lower reservoir 2. The multi-stage energy storage reservoir 5 is constructed on the hills on both sides of the upper reservoir 1 and / or the lower reservoir 2 and is connected to the water pressurizing device 4. The horizontal plane of the energy storage reservoir 5 is higher than the horizontal plane of the upper reservoir 1. The open channel 101 is connected to the gas producing device 3 through a plurality of drainage pipes 103 along the way, which is used to introduce the water in the open channel 101 into the gas producing device 3. The gas producing device 3 is connected to the water pressurizing device 4, which is used to introduce the generated compressed air into the water pressurizing device 4. The forebay 102 is connected to the water pressurizing device 4. The forebay 102 is used to adjust the flow rate so that the water flow at the end of the open channel 101 can be smoothly led to the water inlet of the water pressurizing device 4, providing good water inlet conditions. Specifically, the gas producing device 3 includes a first gas producing tank 301 and a gas storage tank 302. The first gas producing tank 301 is respectively provided with a first water inlet 3011, a first air replenishment port 3012, a first air outlet 3013 and a first water inlet and outlet 3014. Multiple drainage pipes 103 are all connected to the first water inlet 3011. Multiple drainage pipes 103 can be converged together and then connected to the first water inlet 3011. Alternatively, multiple first water inlets 3011 can be set on the first gas producing tank 301 and connected to the drainage pipes 103 respectively, the first air outlet 3013 is connected to the gas storage tank 302, the first air replenishment port 3012 is connected to the external atmosphere, the first water inlet and outlet 3014 is connected to the lower reservoir 2, and valves 6 are correspondingly provided on the pipelines connecting the drainage pipe 103, the first air replenishment port 3012, the first air outlet 3013 and the first water inlet and outlet 3014. The multi-stage energy storage reservoir 5 is provided with at least six stages, and the height difference between each stage of the energy storage reservoir 5 is marked as Hn, and the height difference between the upper reservoir 1 and the gas production device 3 is marked as H, then H is greater than Hn, ensuring that the compressed air can pressurize the water into the corresponding energy storage reservoir 5. The water pressure device 4 includes several groups of water pressure tanks 401, gas delivery columns 402 and water delivery columns 403. The gas outlet of the gas storage tank 302 is connected to the gas delivery column 402, and the multi-stage energy storage reservoir 5 is connected to the water delivery column 403 respectively. Several groups of water pressure tanks 401 are arranged longitudinally between the gas delivery column 402 and the water delivery column 403 and correspond to the multi-stage energy storage reservoir 5. The front pool 102 is connected to the water delivery column 403 and the water inlet of the bottom water pressure tank 401. The water outlet of the lower water pressure tank 401 is divided into two paths, one of which is connected to the upper water pressure tank 401. The water inlet of the pressure water tank 401 is connected, and another way is connected to the water delivery column 403. The air inlet of the water tank is connected to the air delivery column 402. The pipeline connecting the multi-stage energy storage reservoir 5 and the water delivery column 403, the pressure water tank 401 and the water delivery column 403, the pressure water tank 401 and the air delivery column 402, and the pipeline connecting the water outlet of the lower pressure water tank 401 and the water inlet of the upper pressure water tank 401 are respectively provided with valves 6. The pressure water tank 401 is provided with an air release port 4011, and a valve 6 is provided at the air release port 4011.The present invention utilizes the process of water in the open channel 101 of the upper reservoir 1 flowing downward, and the gravitational potential energy is converted into kinetic energy, which rushes into the gas production device 3 to compress the air originally in the gas production device 3, and the water head is converted into compressed air. After the compressed air is generated, the compressed air enters the water pressure device 4 and is released to expand, and the water flowing into the water pressure device 4 from the front pool 102 is pressed out and lifted to the multi-stage energy storage reservoirs 5 for energy storage. Compared with traditional pumped storage, the present invention can reduce energy loss and has higher energy utilization rate.

[0023] In a preferred embodiment, the gas producing device 3 also includes a second gas producing tank 303. The structural principle of the second gas producing tank 303 is similar to that of the first gas producing tank 301. The second gas producing tank 303 is also arranged under the water surface of the lower reservoir 2. A second water inlet 3031, a second air replenishment port 3032, a second air outlet 3033 and a second water inlet and outlet 3034 are respectively provided on the second gas producing tank 303. The bottom end of the water delivery column 403 is connected to the second water inlet 3031, the second air outlet 3033 is connected to the gas storage tank 302, the second air replenishment port 3032 is connected to the external atmosphere, and the second water inlet and outlet 3034 are connected to the lower reservoir 2. The water delivery column 403, the second air replenishment port 3032, the second air outlet 3033 and the second water inlet and outlet 3034 are connected. Valves 6 are respectively provided on the pipelines connected to the second air replenishment port 3032, the second air outlet port 3033 and the second water inlet and outlet port 3034. When releasing energy, the multi-stage energy storage reservoir 5 of the present invention can use the water head of the multi-stage energy storage reservoir 5 to pressurize the second gas production tank 303 to generate compressed air, and then enter the first gas production tank 301 through the gas storage tank 302, and press out the water in the lower reservoir 2 that flows into the first gas production tank 301 through the first water inlet and outlet port 3014, return to the open channel 101 along the drainage pipe 103 and finally flow back to the upper reservoir 1, and use the original power generation device of the upper reservoir 1 to generate electricity without building multiple special pumped storage power stations, effectively reducing costs.

[0024] Embodiment 2:

[0025] See also Figures 1 to 4 The multi-stage pumped storage method disclosed in this embodiment uses the multi-stage pumped storage system in Example 1 to perform pumped storage, including the following steps:

[0026] S1. Select the upstream of the existing hydropower station dam as the upper reservoir 1, and the downstream river channel as the lower reservoir 2. Open channels 101 are opened on both sides of the upper reservoir 1 and / or the lower reservoir 2. The starting end of the open channel 101 is connected with the upper reservoir 1, and the end of the open channel 101 is connected with the forebay 102. The horizontal height of the open channel 101 is the same as the flood limit water level of the upper reservoir 1. When the water level of the upper reservoir 1 is higher than the flood limit water level, the open channel 101 keeps water flowing into the forebay 102. The open channel 101 flows from both sides of the upper reservoir 1 along the banks toward the lower reservoir 2 and enters the forebay 102.

[0027] S2. A gas producing device 3 is arranged in the lower reservoir 2, and a multi-stage energy-storage reservoir 5 is constructed which is higher than the water level of the upper reservoir 1 according to the topography of the upper reservoir 1 and / or the two banks of the lower reservoir 2. The multi-stage energy-storage reservoir 5 is arranged in a stepped manner and gradually rises. A plurality of drainage pipes 103 are arranged along the flow from the open channel 101 to the front pool 102. The drainage pipes 103 may be natural holes on both banks, which are used to discharge water toward the lower reservoir 2, that is, the drainage pipes 103 discharge water into the gas producing device 3 arranged in the lower reservoir 2, and the water head rushing down from the open channel 101 enters the gas producing device 3 and is converted into compressed air. The generated compressed air enters the gas storage tank 302 for storage for standby use.

[0028] S3. A water delivery column 403 and a gas delivery column 402 are provided inside the mountain of the multi-stage energy storage reservoir 5. The water delivery column 403 and the gas delivery column 402 can be replaced by vertical shafts naturally formed inside the mountain or artificially dug. Each stage of the energy storage reservoir 5 is connected to the water delivery column 403, and a water pressure device 4 is provided between the water delivery column 403 and the gas delivery column 402. The water pressure device 4 at the bottom is connected to the front pool 102, and the water outlet end of the water pressure device 4 is connected to the water delivery column 403, and the air inlet end of the water pressure device 4 is connected to the gas delivery column 402.

[0029] S4, using the compressed air generated in step S2 to enter the water pressure device 4 to release energy, and pressurize the water entering the water pressure device 4 from the front pool 102 to the corresponding multi-stage energy storage reservoir 5 for pumping and energy storage. Specifically, the gas production device 3 includes a first gas production tank 301 and a gas storage tank 302, the first gas production tank 301 is connected to the gas storage tank 302, and multiple drainage pipes 103 are connected to the first gas production tank 301. The water in the open channel 101 rushes down along the drainage pipe 103 into the first gas production tank 301, compressing the original air in the first gas production tank 301, and the generated compressed air enters the gas storage tank 302 for storage. When the first gas production tank 301 is full of water, the valve 6 on the drainage pipe 103 is closed, and part of the compressed air stored in the gas storage tank 302 is released back to the first gas production tank 301, and the water in the first gas production tank 301 is discharged to the lower reservoir 2 along the first water inlet and outlet 3014, and then the valve 6 on the drainage pipe 103 is opened to release The water is compressed for the next time to continuously produce compressed air, and the generated compressed air is used for pumped storage; the water pressure device 4 includes several groups of water pressure tanks 401, and the layout height of the water pressure tanks 401 corresponds to the layout height of the multi-stage energy storage reservoir 5. The water inlet of the lowest water pressure tank 401 is connected to the front pool 102, and the water outlet of the water pressure tank 401 is divided into two paths, one is connected to the water inlet of the upper water pressure tank 401, and the other is connected to the water delivery column 403. When the energy storage reservoir 5 corresponding to the water pressure tank 401 is full of pumped water or needs to be pumped to the corresponding height reservoir for water storage, the water pressed upward in the water pressure tank 401 enters the water pressure tank 401 of the upper level for relay water lifting, and the water is pumped to the energy storage reservoir 5 of the corresponding height for energy storage. In order to ensure that the generated compressed air can smoothly and effectively lift the water pressure in the pressure tank 401 and enter the energy storage reservoir 5 for storage, the height difference between the multi-stage energy storage reservoirs 5 is less than the height difference from the open channel 101 to the gas production device 4; the gas production device 3 also includes a second gas production tank 303, the second gas production tank 303 is connected to the gas storage tank 302, and the bottom end of the water delivery column 403 is connected to the second gas production tank 303; when the multi-stage energy storage reservoir 5 releases energy, water is released one by one from the highest level energy storage reservoir 5, and the water flows down along the water delivery column 403 into the second gas production tank 303 to compress the original air in the second gas production tank 303, and the generated compressed air enters the gas storage tank 302 for storage, and then the generated compressed air is used to press the water entering the first gas production tank 301 from the lower reservoir 2 upward along the drainage pipe 103 back into the open channel 101, and finally returns to the upper reservoir 1, and the original power station of the upper reservoir 1 is used to generate electricity, effectively reducing the investment cost.

[0030] In the specific example, the upstream of Longtan Hydropower Station is selected as the upper reservoir 1, and the river between Longtan Hydropower Station and Yantan is selected as the lower reservoir 2. A 4km long open channel 101 is opened on the mountains on both sides of the dam of Longtan Hydropower Station. The normal water storage level of Longtan Hydropower Station is 375m, and the flood limit water level is 359m. The normal water storage level of Yantan is 223m, and the flood limit water level is 204m. There are 4 holes along the 4km long open channel 101 that drain water to the lower reservoir 2. These holes are used as drainage pipes 103. The first gas production tank 301 is set at Yantan 2 It is preferably set at the flood limit water level of 204m or the normal water level of 223m at Yantan, and adjusted according to different working conditions. That is, when the upper reservoir 1 releases water to generate compressed air for pumping energy storage, it is preferably set at the flood limit water level of 204m, and the water head of the gas produced by flushing from the open channel 101 into the first gas production tank 301 is 171m. When high-head water is released from the multi-stage energy storage reservoir 5 to generate compressed air to pump water from the lower reservoir 2 to the upper reservoir 1 for power generation, it is preferably set at the normal water level of 223m, and the water pumped from the lower reservoir 2 to the upper reservoir 1 is 136m high. When compressed air is produced for pumped storage, the water in the open channel 101 rushes down along the drainage pipe 103, enters the first gas production tank 301 from the first water inlet 3011 at the bottom of the first gas production tank 301, compresses the gas in the first gas production tank 301 to produce compressed air, and the generated compressed air enters the gas storage tank 302 for storage and standby use; according to the mountain terrain on both sides of the river, 6 energy storage reservoirs 5 are excavated, and the height difference between each level of energy storage reservoirs 5 is 125m-130m. Two vertical shafts are dug in the mountain as water delivery columns 403 and gas delivery columns 402. Each level of energy storage reservoirs 5 is connected to the water delivery column 403, and a valve is provided on the connecting pipeline. The door 6 controls the water in and out; the water pressure device 4 is provided with 6 water pressure tanks 401, and the 6 water pressure tanks 401 are vertically arranged in the mountain. The water inlet of the lowest water pressure tank 401 is connected with the front pool 102. When pumping water for energy storage, water enters the water pressure tank 401 from the front pool 102, and then the valve 6 of the water inlet and the air release port 4011 is closed, and the water outlet and air inlet valve 6 of the water pressure tank 401 is opened, and the compressed air in the gas transmission column 402 is pressed into the water pressure tank 401, and the water is pressed out from the water outlet of the water pressure tank 401 to the corresponding level of the energy storage reservoir 5 or enters the previous water pressure tank 401 for relay lifting to the higher energy storage reservoir 5 for pumping water for energy storage. When the multi-stage energy-storage reservoir 5 releases water to release energy, water is released step by step from the highest energy-storage reservoir 5 along the water delivery column 403 into the second gas production tank 303 to generate compressed air. The compressed air generated by the water release is used to lift the water in the first gas production tank 301 from the lower reservoir 2 along the drainage pipe 103 for 136m to the open channel 101, and finally enters the upper reservoir 1, and the power generation equipment in the upper reservoir is used to generate electricity, which makes full use of the land resources beside the river bank of the reservoir as an energy-storage reservoir, effectively improves energy utilization, and reduces construction costs.

[0031] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, they can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples" or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A multi-stage pumped storage system, characterized in that: It includes an upper reservoir, a lower reservoir, a gas producing device, a water pressurizing device, and a multi-stage energy storage reservoir. Open channels are opened on both sides of the upper reservoir. The open channels are connected to a forebay. The gas producing device is arranged at the lower reservoir. The multi-stage energy storage reservoirs are built on the mountains on both sides of the upper reservoir and / or the lower reservoir and are connected to the water pressurizing device. The open channel is connected to the gas producing device through multiple drainage pipes. The gas producing device is connected to the water pressurizing device, and the forebay is connected to the water pressurizing device. The water head of the upper reservoir enters the gas producing device to generate compressed air and then enters the water pressurizing device. The water flowing from the forebay into the water pressurizing device is lifted to the multi-stage energy storage reservoirs for energy storage.

2. The multi-stage pumped storage system according to claim 1, characterized in that: The gas production device includes a first gas production tank and a gas storage tank. The first gas production tank is respectively provided with a first water inlet, a first air supply port, a first air outlet and a first water inlet and outlet. The plurality of drainage pipes are connected to the first water inlet, the first air outlet is connected to the gas storage tank, the first air supply port is connected to the external atmosphere, the first water inlet and outlet are connected to the lower reservoir, and valves are respectively provided on the pipelines connecting the drainage pipe, the first air supply port, the first air outlet and the first water inlet and outlet.

3. The multi-stage pumped storage system according to claim 2, characterized in that: The water pressure device includes several groups of water pressure tanks, gas delivery columns and water delivery columns. The gas outlet of the gas storage tank is connected to the gas delivery column. The multiple energy storage reservoirs are connected to the water delivery columns respectively. Several groups of water pressure tanks are longitudinally arranged between the gas delivery column and the water delivery column and correspond to the multiple energy storage reservoirs. The fore pool is connected to the water delivery column and the water inlet of the water pressure tank at the bottom. The water outlet of the lower water pressure tank is divided into two paths, one is connected to the water inlet of the upper water pressure tank, and the other is connected to the water delivery column. The air inlet of the water tank is connected to the gas delivery column. The valves are correspondingly arranged on the pipelines connecting the multiple energy storage reservoirs and the water delivery column, the water pressure tank and the water delivery column, the water pressure tank and the gas delivery column, and the water outlet of the lower water pressure tank and the water inlet of the upper water pressure tank, respectively. The water pressure tank is provided with an air release port, and a valve is provided at the air release port.

4. The multi-stage pumped storage system according to claim 3, characterized in that: The gas producing device also includes a second gas producing tank, on which a second water inlet, a second air replenishment port, a second air outlet and a second water inlet and outlet are respectively provided, the bottom end of the water delivery column is connected with the second water inlet, the second air outlet is connected with the gas storage tank, the second air replenishment port is connected with the external atmosphere, and the second water inlet and outlet are connected with the lower reservoir, and valves are respectively provided on the pipes connecting the water delivery column, the second air replenishment port, the second air outlet and the second water inlet and outlet, and the water head of the multi-stage energy storage reservoir enters the second gas producing tank to generate compressed air, and then enters the first gas producing tank through the gas storage tank, and the water in the lower reservoir that flows into the first gas producing tank through the first water inlet and outlet is pressed out, returns to the open channel along the drainage pipe and finally flows back to the upper reservoir.

5. The multi-stage pumped storage system according to any one of claims 1 to 4, characterized in that: The multi-level energy storage reservoir has at least six levels, and the height difference between each level of the energy storage reservoir is marked as H n , the height difference between the upper reservoir and the gas production device is marked as H, then H is greater than H n .

6. A multi-stage pumped storage method, characterized in that: Using the multi-stage pumped storage system according to any one of claims 1 to 5 to perform pumped storage comprises the following steps: S1. Select the upstream of the existing hydropower station dam as the upper reservoir and the downstream river channel as the lower reservoir. Open channels are opened on both sides of the upper reservoir and / or the lower reservoir. The starting end of the open channel is connected to the upper reservoir, and the end of the open channel is connected to the fore pool. S2. A gas production device is installed in the lower reservoir, and a multi-stage energy storage reservoir is constructed that is higher than the water level of the upper reservoir according to the topography of the upper reservoir and / or the lower reservoir. The multi-stage energy storage reservoir is arranged in a stepped manner, and a plurality of drainage pipes are provided along the flow from the open channel to the forebay. The drainage pipes discharge water into the gas production device installed in the lower reservoir, and the water head rushing down from the open channel enters the gas production device and is converted into compressed air; S3. A water delivery column and a gas delivery column are provided on the mountain of the multi-stage energy storage reservoir. Each stage of the energy storage reservoir is connected to the water delivery column, and a water pressure device is provided between the water delivery column and the gas delivery column. The water pressure device at the bottom is connected to the fore pool, the water outlet of the water pressure device is connected to the water delivery column, and the air inlet of the water pressure device is connected to the gas delivery column; S4, using the compressed air generated in step S2 to enter the water pressure device to release energy, and pressurizing the water entering the water pressure device from the fore pool to the corresponding multi-stage energy storage reservoir for pumped storage.

7. The multi-stage pumped storage method according to claim 6, characterized in that: The gas producing device includes a first gas producing tank and a gas storage tank. The first gas producing tank is connected to the gas storage tank. Multiple drainage pipes are connected to the first gas producing tank. Water in the open channel rushes down along the drainage pipe into the first gas producing tank to compress the original air in the first gas producing tank. The generated compressed air enters the gas storage tank for storage. When the first gas producing tank is full of water, the valve on the drainage pipe is closed to release part of the compressed air stored in the gas storage tank and return it to the first gas producing tank. The water in the first gas producing tank is discharged to the lower reservoir along the first water inlet and outlet. Then the valve on the drainage pipe is opened to release water for the next compression to continuously produce compressed air. The generated compressed air is used for pumped storage in step S4.

8. The multi-stage pumped storage method according to claim 7, characterized in that: The gas production device also includes a second gas production tank, which is connected to the gas storage tank, and the bottom end of the water delivery column is connected to the second gas production tank; when the multi-stage energy storage reservoir releases energy, water is released one by one from the highest-level energy storage reservoir, and the water flows down along the water delivery column into the second gas production tank to compress the original air in the second gas production tank, and the generated compressed air enters the gas storage tank for storage, and then the generated compressed air is used to press the water entering the first gas production tank from the lower reservoir along the drainage pipe back into the open channel, and finally returns to the upper reservoir, and uses the original power station in the upper reservoir to generate electricity.

9. The multi-stage pumped storage method according to claim 8, characterized in that: The water pressure device includes several groups of water pressure tanks. The layout height of the water pressure tanks corresponds to the layout height of the multi-stage energy-storage reservoirs. The water inlet of the lowest water pressure tank is connected with the front pool. The water outlet of the water pressure tank is divided into two paths, one is connected with the water inlet of the upper water pressure tank, and the other is connected with the water delivery column. When the energy-storage reservoir corresponding to the water pressure tank is fully pumped or needs to be pumped to the corresponding height reservoir for water storage, the water pressed upward in the water pressure tank enters the water pressure tank of the upper level for relay water lifting, and the water is pumped to the energy-storage reservoir of the corresponding height for energy storage.

10. The multi-stage pumped storage method according to claim 9, characterized in that: The height difference between the multi-stage storage reservoirs is smaller than the height difference from the open channel to the gas production device.

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