Pumped storage system coupled with constant-pressure compressed air energy storage device

Abstract

The utility model provides a pumped storage system coupled with a constant-pressure compressed air energy storage device, which comprises a pumped storage device and a compressed air energy storage device, and the pumped storage device comprises an upper reservoir, a high-pressure water diversion pipeline and a lower reservoir; the upper reservoir is communicated with the first end of the high-pressure water diversion pipeline, the second end of the high-pressure water diversion pipeline is communicated with the compressed air energy storage device through a first waterway pipeline, and the height difference exists between the upper reservoir and the compressed air energy storage device in the vertical direction. A pressure stabilizing unit is arranged at the joint of the high-pressure water diversion pipeline and the first water path pipeline, and the second end of the high-pressure water diversion pipeline is communicated with the lower reservoir through a second water path pipeline. By means of the pumped storage system, under the condition that an existing hydraulic structure of the pumped storage device is not changed, capacity expansion and transformation of pumped storage can be achieved by supplementing the compressed air energy storage device, the adjusting capacity is indirectly increased, and the capacity of a pumped storage service power grid is improved.

Description

Technical Field

[0001] This application relates to the field of power energy storage technology, and in particular to a pumped-storage system coupled with a constant-pressure compressed air energy storage device. Background Technology

[0002] With the accelerated construction of new power systems, the uncertainty of wind and solar power output has exacerbated the power balance problem, necessitating flexible adjustment methods for the power grid. Pumped storage, as the most technologically mature, economically optimal, and readily scalable green regulating power source, plays a crucial role in ensuring power supply, grid security, and promoting the integration of new energy sources. However, pumped storage projects involve large-scale construction and long construction periods, approximately 6-8 years. When grid demand increases, pumped storage systems are generally not suitable for capacity expansion or upgrades. Due to limitations imposed by pump characteristics, pumped storage operates with a constant power output during pumping, making real-time adjustments impossible to meet the urgent regulatory resource demands of a new power system primarily based on new energy sources. Utility Model Content

[0003] In view of this, the purpose of this application is to propose a pumped-storage energy storage system coupled with a constant-pressure compressed air energy storage device to solve the problem that pumped-storage energy storage systems cannot be flexibly expanded.

[0004] Based on the above objectives, the first aspect of this application provides a pumped-storage system coupled with a constant-pressure compressed air energy storage device, including a pumped-storage device and a compressed air energy storage device, wherein the pumped-storage device includes an upper reservoir, a high-pressure water intake pipeline, and a lower reservoir.

[0005] The upper reservoir is connected to the first end of the high-pressure water diversion pipeline, and the second end of the high-pressure water diversion pipeline is connected to the compressed air energy storage device through the first waterway pipeline. There is a height difference between the upper reservoir and the compressed air energy storage device in the vertical direction. A pressure stabilizing unit is provided at the connection between the high-pressure water diversion pipeline and the first waterway pipeline.

[0006] The second end of the high-pressure water diversion pipeline is connected to the lower reservoir via a second waterway pipeline.

[0007] Optionally, the compressed air energy storage device includes an air storage tank, a compressor unit, and an expander unit;

[0008] The second end of the high-pressure water intake pipe is connected to the first port at the bottom of the gas storage tank via the first water pipe, the compressor unit is connected to the second port at the top of the gas storage tank, and the expander unit is connected to the third port at the top of the gas storage tank.

[0009] Optionally, the compressed air energy storage device further includes a control unit and a liquid level sensor;

[0010] The liquid level sensor is installed inside the gas storage tank. The liquid level sensor is communicatively connected to the control unit. The control unit is communicatively connected to both the compressor unit and the expander unit.

[0011] Optionally, the gas storage facility may include multiple sub-gas storage facilities connected in series.

[0012] Optionally, each sub-gas storage unit has the first port at its bottom; each sub-gas storage unit has the second port at its top, and all the second ports are connected in parallel to the compressor unit; each sub-gas storage unit has the third port at its top, and all the third ports are connected in parallel to the expander unit.

[0013] Optionally, a ball valve is installed on the waterway connecting the first waterway to the first port.

[0014] Optionally, a check valve is provided on the gas line connecting the compressor unit and the second port.

[0015] Optionally, a gate valve is provided on the air line connecting the expander unit and the third port.

[0016] Optionally, the compressed air energy storage device further includes a heat exchange unit, which is connected to the expander unit and the compressor unit respectively.

[0017] Optionally, the pressure stabilizing unit includes a pressure regulating well.

[0018] As can be seen from the above description, the pumped-storage energy storage system with coupled constant-pressure compressed air energy storage device provided in this application includes a pumped-storage energy storage device and a compressed air energy storage device. The pumped-storage energy storage device includes an upper reservoir, a high-pressure water intake pipeline, and a lower reservoir. The upper reservoir is connected to a first end of the high-pressure water intake pipeline, and the second end of the high-pressure water intake pipeline is connected to the compressed air energy storage device through a first waterway pipeline. There is a vertical height difference between the upper reservoir and the compressed air energy storage device. Because the upper reservoir is connected to the compressed air energy storage device, the pressure generated by the water head in the upper reservoir creates a constant-pressure state in the high-pressure gas storage tank of the compressed air energy storage device, where water and high-pressure gas coexist. This improves the operating efficiency of the compressed air energy storage device, reduces the dead storage gas capacity in the compressed air energy storage device, and thus reduces the design capacity of the gas storage tank, saving design costs. A pressure stabilizing unit is provided at the connection between the high-pressure water intake pipeline and the first waterway pipeline, and the second end of the high-pressure water intake pipeline is connected to the lower reservoir through a second waterway pipeline. The pressure stabilizing unit can smooth out large fluctuations in liquid pressure within the pipeline caused by the start-up and shutdown of the pumped storage and compressed air energy storage devices, thus providing bidirectional pressure stabilization. The pumped storage system of this application allows for capacity expansion and modification of pumped storage systems without altering existing hydraulic structures, by supplementing with a constant-pressure compressed air energy storage device. This indirectly increases regulation capacity and enhances the pumped storage's ability to serve the power grid. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the pumped water storage system of the coupled constant pressure compressed air energy storage device according to an embodiment of this application.

[0021] Figure label:

[0022] 01. Pumped storage unit; 010. Upper reservoir; 011. High-pressure water intake pipeline; 012. Lower reservoir; 013. First waterway pipeline; 014. Pressure stabilizing unit; 015. Second waterway pipeline; 016. Underground powerhouse; 02. Compressed air energy storage unit; 020. Gas storage tank; 021. Compressor unit; 022. Expander unit; 023. Control unit; 0201. Sub-gas storage tank; 0202. Ball valve; 0211. Check valve; 0221. Gate valve; 024. Heat exchange unit; 025. Drying unit. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0024] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar words used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate...

[0025] Relative positional relationships can change if the absolute position of the object being described changes.

[0026] As described in the background section, pumped storage power stations cannot be flexibly expanded; their power regulation range is fixed during power generation, and discontinuous during energy storage. To address this issue, the applicant utilizes the site resources of pumped storage power stations to construct compressed air energy storage devices. By supplementing these devices, the power regulation range of pumped storage is broadened, indirectly increasing regulation capacity and effectively improving the power regulation range of the pumped storage system to quickly supplement the insufficient grid regulation resources.

[0027] Compressed air energy storage (CASS) is another large-scale physical energy storage technology besides pumped hydro storage. It stores and releases electrical energy by compressing and expanding air. During storage, an electrically driven CASS device compresses air to high pressure and stores it in a high-pressure gas storage tank. During release, the high-pressure gas drives an expander unit to generate electricity. Coupling pumped hydro storage systems with CASS devices supplements pumped hydro storage capacity and improves the efficiency of pumped hydro storage in serving the power grid.

[0028] When a pumped-storage system is coupled with a compressed-air energy storage device, the pressure generated by the upper reservoir in the pumped-storage system creates a constant-pressure state where liquid and high-pressure gas coexist in the compressed-air storage tank. This avoids the efficiency reduction caused by variable-pressure operation of the expander system in the compressed-air storage device, reduces the design capacity of the storage tank, and saves costs. This application utilizes the hydropower resources of the upper reservoir of the pumped-storage system to continuously pressurize the high-pressure gas storage tank in the compressed-air energy storage device, indirectly generating electricity and achieving full utilization of hydropower resources. Simultaneously, by using a constant-pressure compressed-air energy storage device and rationally controlling the output of the compressed-air energy storage, the power adjustment range of the pumped-storage system is broadened, enabling adjustable power output of the pumped-storage pump and improving the efficiency and effectiveness of pumped-storage services to the power grid.

[0029] The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0030] This application provides a pumped-water energy storage system coupled with a constant-pressure compressed air energy storage device, referenced... Figure 1 It includes a pumped storage device 01 and a compressed air energy storage device 02. The pumped storage device 01 includes an upper reservoir 010, a high-pressure water intake pipeline 011, and a lower reservoir 012.

[0031] The upper reservoir 010 is connected to the first end of the high-pressure water intake pipe 011, and the second end of the high-pressure water intake pipe 011 is connected to the compressed air energy storage device 02 through the first water pipe 013. There is a height difference between the upper reservoir 010 and the compressed air energy storage device 02 in the vertical direction. A pressure stabilizing unit 014 is provided at the connection between the high-pressure water intake pipe 011 and the first water pipe 013.

[0032] The second end of the high-pressure water diversion pipeline 011 is connected to the lower reservoir 012 via the second waterway pipeline 015.

[0033] When the pumped-storage hydroelectric power unit 01 and the compressed-air energy storage unit 02 are coupled, a branch water pipe, namely the first water pipe 013, is led out from the high-pressure water intake pipe 011 and connected to the compressed-air energy storage unit 02. One end of the high-pressure water intake pipe 011 is connected to the upper reservoir 010, and the other end is connected to one end of the first water pipe 013. The other end of the first water pipe 013 is connected to the bottom of the compressed-air energy storage unit 02. Simultaneously, the second end of the high-pressure water intake pipe 011 is also connected to the lower reservoir 012 via the second water pipe 015. Because there is a vertical height difference between the upper reservoir 010 and the compressed-air energy storage unit 02, pressure can be generated by the water head of the upper reservoir 010, allowing the liquid in the pumped-storage hydroelectric power unit 01 to flow into the compressed-air energy storage unit 02 through the first water pipe 013, thus enabling the gas storage tank in the compressed-air energy storage unit 02 to achieve constant pressure coexistence of liquid and high-pressure gas. When the high-pressure gas in the gas storage tank increases, it exerts pressure on the liquid in the tank, causing the liquid to flow back into the high-pressure water inlet pipe 011, thus maintaining a constant pressure in the gas storage tank. Conversely, when the high-pressure gas in the tank decreases, the liquid in the high-pressure water inlet pipe 011 can flow into the gas storage tank, maintaining a constant pressure. This ensures constant pressure operation of the expander unit in the compressed air energy storage device 02, avoiding efficiency reduction caused by variable pressure operation and improving the operating efficiency of the expander unit.

[0034] The power output of the compressed air energy storage device 02 can be connected to the nearest pumped storage switch station, making full use of the existing pumped storage power output resources, achieving resource sharing for power access, and saving costs. The ground-based centralized control platform controls the output of the pumped storage device 01 and the compressed air energy storage device 02.

[0035] Furthermore, to prevent significant pressure fluctuations in the liquid within the pipelines during start-up and shutdown of the pumped-storage hydroelectric power unit 01 and the compressed-air power storage unit 02, which could affect their operation, a pressure stabilizing unit 014 is installed at the connection between the high-pressure water inlet pipeline 011 and the first water path pipeline 013 in this embodiment. The pressure stabilizing unit 014 smooths out large pressure fluctuations in the liquid. The pressure stabilizing unit 014 has a bidirectional pressure stabilizing function. Before the liquid in the pumped-storage hydroelectric power unit 01 flows into the compressed-air power storage unit 02, it is first stabilized by the pressure stabilizing unit 014, and then flows into the compressed-air power storage unit 02. This prevents the liquid in the pumped-storage hydroelectric power unit 01 from flowing into the compressed-air power storage unit 02 when pressure fluctuations are large, thus avoiding any impact on the operation of the compressed-air power storage unit 02. Correspondingly, before the liquid flows back from the compressed air energy storage device 02 to the high-pressure water pipe 011, it will also pass through the pressure stabilizing unit 014 for pressure stabilization, so that the operation of the compressed air energy storage device 02 will not affect the water pressure of the pumped water storage device 01.

[0036] For example, in this embodiment, the pressure stabilizing unit 014 is a surge tank. The pressure stabilizing unit 014 ensures the safety of the waterway, preventing interference between the pumped-storage water supply and the compressed-air energy storage water supply. The pressure stabilizing unit 014 is located tens to hundreds of meters from the pumped-storage water intake tunnel. It is formed by excavating a rock cavern, creating a closed air chamber surrounded by rock walls and a water surface, which can be lined with concrete. Specifically, the lower part is cylindrical, and the upper part is domed; the upper part is filled with compressed air, and the lower part is filled with water. When the operation of the pumped-storage device 01 or the compressed-air energy storage device 02 causes hydraulic fluctuations in the waterway, the high-pressure air in the pressure stabilizing unit 014's air chamber forms an air cushion to suppress the amplitude of water level fluctuations, thereby stabilizing the impact of transient water flow changes in the waterway and ensuring that the two systems do not hydraulically interfere with each other. During the hydraulic transition process of pumped storage units, which involves large fluctuations such as load shedding, the pressure can reach 1.3-1.4 times the static pressure. The design of the water intake system and ball valves for pumped storage needs to take into account the impact of the transition process, resulting in high construction costs. Compressed air energy storage device 02 is connected to pumped storage device 01 through pressure stabilizing unit 014, effectively reducing the design and selection difficulty and cost of the water pipeline and ball valves for compressed air energy storage device 02.

[0037] The second waterway pipeline 015 also includes an underground powerhouse 016 for the pumped-storage hydroelectric power unit 01, which contains the core unit of the pumped-storage hydroelectric power unit 01. Liquid in the upper reservoir 010 flows into the underground powerhouse 016 through the second waterway pipeline 015. After generating electricity or storing energy through the core unit in the underground powerhouse 016, the liquid then flows into the lower reservoir 012 through the second waterway pipeline 015.

[0038] In the pumped-storage system with coupled constant-pressure compressed air energy storage provided in this application, since the upper reservoir 010 is connected to the compressed air energy storage device 02, the water head of the upper reservoir 010 creates a constant-pressure state in the high-pressure gas storage tank of the compressed air energy storage device 02, where water and high-pressure gas coexist. This improves the operating efficiency of the compressed air energy storage device 02, reduces the dead storage gas capacity in the compressed air energy storage device 02, and thus reduces the design capacity of the gas storage tank, saving design costs. A pressure stabilizing unit 014 is installed at the connection between the high-pressure water intake pipe 011 and the first water pipe 013. The pressure stabilizing unit 014 prevents the liquid flowing into the compressed air energy storage device 02 from affecting the water pressure of the pumped-storage device 01 during backflow, thereby stabilizing the water pressure. Through the pumped-storage system of this application, the capacity expansion and modification of pumped-storage can be achieved by supplementing the constant-pressure compressed air energy storage device without changing the existing hydraulic structures of the pumped-storage device, indirectly increasing the regulation capacity and improving the pumped-storage's ability to serve the power grid. The compressed air energy storage device 02 does not change the original pumped storage structure design. The water pipeline can be constructed using the construction support tunnel of the pumped storage high-pressure water diversion system, which facilitates the expansion and renovation of the pumped storage power station.

[0039] In some embodiments, the compressed air energy storage device 02 includes an air storage tank 020, a compressor unit 021, and an expander unit 022;

[0040] The second end of the high-pressure water pipe 011 is connected to the first port at the bottom of the gas storage tank 020 through the first water pipe 013, the compressor unit 021 is connected to the second port at the top of the gas storage tank 020, and the expander unit 022 is connected to the third port at the top of the gas storage tank 020.

[0041] Specifically, the first port at the bottom of the gas storage tank 020 is connected to the first water pipe 013, allowing liquid in the pumped storage device 01 to flow into or out of the gas storage tank 020 through the first port. The second port at the top of the gas storage tank 020 is connected to the compressor unit 021, which compresses atmospheric air, and the compressed gas enters the gas storage tank 020 through the second port for storage. The third port at the top of the gas storage tank 020 is connected to the expander unit 022, allowing the compressed gas stored in the gas storage tank 020 to enter the expander unit 022 through the third port, driving the expander unit 022 to generate electricity.

[0042] The head height between the upper reservoir 010 and the gas storage tank 020 of the pumped storage unit 01 is denoted as H, and the pressure inside the gas storage tank 020 is denoted as Pa, where Pa = ρgH. Generally, the head height of the upper reservoir of a pumped storage unit is much greater than the water level fluctuation of the pumped storage unit, and the pressure Pa inside the gas storage tank remains approximately constant.

[0043] The compressor unit 021 and expander unit 022 in the compressed air energy storage device 02 are both located on open ground near the pumped storage device 01. The pressure stabilizing unit 014 and the first water pipeline 013 are located inside the pumped storage mountain below ground level.

[0044] Furthermore, to increase the high-pressure gas storage capacity of the compressed air energy storage device 02 and reduce the volume of the gas storage tank 020, the design pressure Ps of the gas storage tank 020 is generally higher than the inlet pressure Pi of the expander unit 022. During energy release, the high-pressure air is released from the gas storage tank 020, and needs to be reduced to the inlet pressure Pi of the expander unit 022 through a pressure reducing valve before driving the expander unit to generate electricity. Ps > Pi, resulting in energy loss during the pressure reducing process. Simultaneously, the gas pressure in the gas storage tank 020 gradually decreases during the energy release process. When the actual pressure of the gas storage tank 020 is lower than the inlet pressure Pi of the expander unit 022, the expander unit 022 stops working. At this time, the gas pressure in the gas storage tank 020 is higher than that of atmospheric air, but lower than the operating pressure of the expander unit 022. The remaining gas in the gas storage tank 020 forms dead storage gas, which occupies storage space and increases storage costs, but does not generate energy release benefits. The pumped-storage system provided in this embodiment reduces the dead storage gas volume in the gas storage tank 020 of the compressed-air energy storage device 02 by introducing the liquid from the pumped-storage device 01 into the gas storage tank 020 of the compressed-air energy storage device 02. This significantly reduces the volume of the gas storage tank 020 for the same power generation, saving construction costs. Simultaneously, the compressed-air energy storage device 02 indirectly utilizes the dead storage water resources in the upper reservoir of the pumped-storage device 01 to generate electricity, maximizing resource utilization efficiency. The pressure generated by the water head in the upper reservoir 010 creates a constant pressure state in the gas storage tank 020 where water and high-pressure gas coexist, ensuring that the expander unit 022 operates at its optimal point and improving the operating efficiency of the expander unit 022.

[0045] In some embodiments, the compressed air energy storage device 02 further includes a control unit 023 and a liquid level sensor;

[0046] The liquid level sensor is installed inside the gas storage tank 020. The liquid level sensor is communicatively connected to the control unit 023. The control unit 023 is communicatively connected to the compressor unit 021 and the expander unit 022 respectively.

[0047] Specifically, a liquid level sensor is installed inside the gas storage tank 020 to detect the liquid level inside. The control unit 023 collects the liquid level data measured by the sensor. When the liquid level reaches the upper or lower limit, the control unit 023 can control the compressor unit 021 or the expander unit 022 to stop operating. Most of the equipment in the compressed air energy storage device 02, such as the control unit 023, compressor unit 021, and expander unit 022, is located on open ground near the pumped hydro storage device 01. The gas storage tank 020 can be located on open ground or underground. The liquid level sensor allows for real-time monitoring of the liquid level in the gas storage tank 020, enabling timely control of the compressor unit 021 to stop operating and prevent excessive compressed gas from leaking out from the first port at the bottom of the gas storage tank 020. Simultaneously, it also facilitates timely control of the expander unit 022 to stop operating, preventing the release of excessive compressed air and the leakage of liquid from the third port in the gas storage tank 020.

[0048] In some embodiments, the gas storage tank 020 includes a plurality of sub-gas storage tanks 0201 arranged in series. Each sub-gas storage tank 0201 has a first port at its bottom. Each sub-gas storage tank 0201 has a second port at its top. All the second ports are connected in parallel and communicate with the compressor unit 021. Each sub-gas storage tank 0201 has a third port at its top. All the third ports are connected in parallel and communicate with the expander unit 022.

[0049] like Figure 1 As shown, the gas storage 020 in this embodiment includes three sub-gas storage 0201s, which are connected in series. The gas storage 020 can be configured as a pressure vessel or an underground artificial gas storage facility, depending on the requirements. When the gas storage 020 is a pressure vessel, it can be located on open ground outside the underground pumped storage powerhouse, near the high-pressure water intake pipeline 011, and arranged horizontally with other equipment. The pressure vessel can be designed as follows: Figure 1 The spherical sub-gas storage unit 0201 shown can be arranged using a series and parallel pipeline configuration. The number of sub-gas storage units 0201 can be set according to actual needs. Figure 1 The number of neutron gas storage cells 0201 is for illustrative purposes only and is not intended to be limiting. When gas storage cell 020 is an underground artificial gas storage cell, it can be expanded by utilizing the construction adits left over from the pumped storage construction period, with concrete lining and a sealing layer forming the gas storage cell. For example, the underground artificial gas storage cell can include a ring-shaped gas storage cell or multiple interconnected tunnel-type gas storage cells.

[0050] When multiple sub-gas storage units 0201 are arranged in series, the gas path of the compressor unit 021 introduced into the top of each sub-gas storage unit 0201 is set in parallel, and the gas path of the expander unit 022 introduced into the top of each sub-gas storage unit 0201 is set in parallel, and the opening and closing of each is controlled by the control unit 023.

[0051] In some embodiments, a ball valve 0202 is provided on the water path connecting the first water pipe 013 to the first port. A check valve 0211 is provided on the air path connecting the compressor unit 021 to the second port. A gate valve 0221 is provided on the air path connecting the expander unit 022 to the third port.

[0052] Specifically, in this embodiment, a ball valve 0202 connects the first water pipe 013 and the first port. When the ball valve 0202 is open, liquid can flow in or out from the first port. The ball valve 0202 is located within the pumped storage tank. A check valve 0211 connects the compressor unit 021 and the second port. When the check valve 0211 is open, compressed gas can only flow from the compressor unit 021 into the gas storage tank 020 in one direction; conversely, compressed gas cannot flow. A gate valve 0221 connects the expander unit 022 and the third port. When the gate valve 0221 is open, compressed gas flows from the gas storage tank 020 through the gate valve 0221 into the expander unit 022 to drive the expander unit 022 to generate electricity.

[0053] In some embodiments, the compressed air energy storage device 02 further includes a heat storage and exchange unit 024, which is connected to both the expander unit 022 and the compressor unit 021. The heat storage and exchange unit 024 can both store and release heat. By connecting to either the expander unit 022 or the compressor unit 021, heat exchange with either unit is achieved.

[0054] The operation process of the pumped-storage system of the coupled constant-pressure compressed air energy storage device of this application is described in detail below.

[0055] During the energy storage process, the compressed air energy storage device 02 is used to compress and store atmospheric pressure air. During the compression process, the compressed air causes the liquid stored in the compressed air energy storage device 02 to flow back to the high pressure water pipe 011 via the first water pipe 013 and the pressure stabilizing unit 014.

[0056] During the energy release process, compressed air is released through the compressed air energy storage device 02. During the release process, the liquid in the high-pressure water pipe 011 flows into the compressed air energy storage device 02 through the pressure stabilizing unit 014 and the first water pipe 013.

[0057] Specifically, during the energy storage process, the compressed air energy storage device 02 compresses atmospheric air to generate compressed gas. As the amount of stored compressed gas gradually increases, since the internal air pressure of the compressed air energy storage device 02 is constant, the compressed gas will exert a certain pressure on the liquid originally stored in the compressed air energy storage device 02, causing the liquid to flow from the compressed air energy storage device 02 into the first water pipe 013. After being stabilized by the pressure stabilizing unit 014, it flows back into the high-pressure water pipe 011.

[0058] During the energy release process, the compressed air energy storage device 02 releases compressed gas to generate electricity. As the amount of compressed gas stored decreases, the liquid in the pumped hydro storage device 01 flows into the compressed air energy storage device 02 because the internal air pressure of the compressed air energy storage device 02 remains constant. The liquid in the high-pressure water pipe 011, after being stabilized by the pressure stabilizing unit 014, flows into the compressed air energy storage device 02 via the first water pipe 013.

[0059] The compressed air energy storage device 02 expands the functional adjustment range of the pumped storage device 01, increases the power generation of the turbine, and enables adjustable output of the pump. The entire cycle process consumes no additional water, utilizing only the upper reservoir 010 for pressurization, thus not affecting the pumped storage hydropower resources. Through water circulation, the storage space of dead-capacity gas in the gas storage tank 020 is reduced, significantly decreasing the design volume of the gas storage tank 020 and saving construction investment. Furthermore, the compressed air energy storage device 02 indirectly utilizes the pumped storage dead-capacity water resources for power generation, maximizing resource utilization efficiency.

[0060] Before energy storage begins, the control unit 023 controls the check valve 0211 and the ball valve 0202 to open. The check valve 0211 is located on the gas path connecting the compressor unit 021 to the second port at the top of the gas storage tank 020, and the ball valve 0202 is located on the water path connecting the first water pipe 013 to the first port at the bottom of the gas storage tank 020.

[0061] During the energy storage process, in response to the detection by the liquid level sensor installed in the gas storage tank 020 that the current liquid level has reached the preset lower limit liquid level, the control unit 023 controls the compressor unit 021 to stop running, controls the check valve 0211 to close, and controls the ball valve 0202 to close.

[0062] Specifically, before energy storage begins, control unit 023 opens check valve 0211 and ball valve 0202 to allow compressed gas generated by compressor unit 021 to flow into gas storage tank 020 through check valve 0211, and pushes the liquid in gas storage tank 020 back into the first water pipe 013 through ball valve 0202. After energy storage begins, compressor unit 021 compresses atmospheric air. As the compressed gas in gas storage tank 020 gradually increases, the liquid level in gas storage tank 020 continuously decreases. When the liquid level sensor detects that the current liquid level has reached the preset lower limit, control unit 023 stops compressor unit 021 and closes check valve 0211 and ball valve 0202. At this point, the compressed gas in gas storage tank 020 stops increasing, and the liquid level in gas storage tank 020 stabilizes at the lower limit, completing the energy storage process. During energy storage, gas storage tank 020 maintains a constant pressure.

[0063] Before energy release begins, the control unit 023 controls the opening of gate valve 0221 and ball valve 0202. Gate valve 0221 is located on the gas path connecting the expander unit 022 to the third port at the top of the gas storage tank 020, and ball valve 0202 is located on the water path connecting the first water pipe 013 to the first port at the bottom of the gas storage tank 020. In response to the liquid level sensor in the gas storage tank 020 detecting that the current liquid level has reached a preset upper limit, the control unit 023 controls the expander unit 022 to stop operating and controls the gate valve 0221 and ball valve 0202 to close.

[0064] Specifically, before energy release begins, control unit 023 opens gate valve 0221 and ball valve 0202, allowing compressed gas in gas storage tank 020 to flow into expander unit 022 from gate valve 0221, and liquid to flow into gas storage tank 202 from first water pipe 013. After energy release begins, compressed gas continuously flows into expander unit 022 from gas storage tank 020. As the compressed gas decreases, the liquid level in gas storage tank 020 gradually rises, and liquid continuously flows into gas storage tank 020 from ball valve 0202. When the liquid level sensor detects that the current liquid level has reached the preset upper limit, control unit 023 stops expander unit 022, closes gate valve 0221, and closes ball valve 0202. At this point, the compressed gas in gas storage tank 020 no longer decreases, and the liquid level in gas storage tank 020 stabilizes at the upper limit, completing the energy release process. During energy release, gas storage tank 020 maintains a constant pressure.

[0065] In addition, since there is a coexistence of water and gas in the gas storage reservoir 020, when the compressed gas in the gas storage reservoir 020 flows into the expander unit 022 through the gate valve 0221, it may carry some water vapor. To avoid affecting the operation of the expander unit 022, a drying unit 025 is provided on the gas path flowing into the expander unit 022 to dry and filter the water vapor in the compressed gas.

[0066] The ground centralized control platform can control the output of the pumped-storage device 01 and the compressed air energy storage device 02. The ground centralized control platform can allocate power to the pumped-storage device 01 and / or the compressed air energy storage device 02 according to the real-time grid dispatching demand P. The following is described by specific examples.

[0067] First, assume that the maximum power generation of a single unit in the pumped-storage device 01 is Psf, the minimum power generation of a single unit is x%*Psf, and the power generation range of a single unit is x%*Psf~Psf. Herein, x% is determined according to the actual situation. Exemplarily, x% = 50%. If the number of units is N, the power generation range of the pumped-storage device 01 is x%*Psf~N*Psf. The pumping power of a single pumped-storage unit is constant and non-adjustable, which is Psc. If the number of units is N, the pumping power of the pumped-storage device 01 is N*Psc. The maximum power generation of the compressed air energy storage device 02 is Pf, and the power generation range is 0-100%Pf. The maximum energy storage power of the compressed air energy storage device 02 is Pc, and the energy storage power range is y%-100%Pc. Herein, y% is determined according to the actual situation. Exemplarily, y% = 70%. Limited by the technical conditions of compressed air energy storage, it is defaulted that Pf <= Psf, and Pf and Pc can be configured with the same power or different powers according to needs. Then, the maximum power generation of the pumped-storage system of the coupled constant-pressure compressed air energy storage device in this application is N*Psf+Pf, and the maximum energy storage power is N*Psc+Pc.

[0068] During the power generation operation:

[0069] 1. When the grid dispatching demand P < Pf, the compressed air energy storage device 02 can give priority to responding to the grid dispatching demand;

[0070] 2. When the grid dispatching demand Pf < P < Psf, the pumped-storage device 01 can respond to the grid demand;

[0071] 3. When the grid dispatching demand Psf < P <= Pf+Psf, the compressed air energy storage device 02 and one unit of the pumped-storage device 01 can jointly respond to the grid demand;

[0072] 4. When the grid dispatching demand Pf+Psf < P < N*Psf, the pumped-storage device 01 can respond to the grid demand;

[0073] 5. When the grid dispatching demand N*Psf < P < Pf + N*Psf, the compressed air energy storage device 02 and N pumped-storage units can jointly respond to the grid demand.

[0074] During the energy storage operation mode:

[0075] 1. When the grid dispatching demand P < Pc, the compressed air energy storage device 02 can preferentially respond to the grid dispatching demand;

[0076] 2. When the grid dispatching demand Pc < P < Psc, the compressed air energy storage device 02 and one unit of the pumped-storage device 01 can jointly respond to the grid demand;

[0077] 3. When the grid dispatching demand Psc < P < N*Psc, the compressed air energy storage device 02 and multiple pumped-storage units can jointly respond to the grid demand;

[0078] 4. When the grid dispatching demand P = Pc + N*Psc, the compressed air energy storage device 02 and N units in the pumped-storage device 01 can jointly respond to the grid demand.

[0079] Those of ordinary skill in the art should understand that: the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present application (including the claims) is limited to these examples; under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present application as described above, and they are not provided in detail for the sake of brevity.

[0080] The embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included within the protection scope of the present application.

Claims

1. A pumped-storage energy system coupled with a constant-pressure compressed air energy storage device, characterized in that, It includes a pumped-storage hydroelectric power system and a compressed-air energy storage system. The pumped-storage hydroelectric power system includes an upper reservoir, a high-pressure water diversion pipeline, and a lower reservoir. The upper reservoir is connected to the first end of the high-pressure water diversion pipeline, and the second end of the high-pressure water diversion pipeline is connected to the compressed air energy storage device through the first waterway pipeline. There is a height difference between the upper reservoir and the compressed air energy storage device in the vertical direction. A pressure stabilizing unit is provided at the connection between the high-pressure water diversion pipeline and the first waterway pipeline. The second end of the high-pressure water diversion pipeline is connected to the lower reservoir via a second waterway pipeline.

2. The system according to claim 1, characterized in that, The compressed air energy storage device includes an air storage tank, a compressor unit, and an expander unit; The second end of the high-pressure water intake pipe is connected to the first port at the bottom of the gas storage tank via the first water pipe, the compressor unit is connected to the second port at the top of the gas storage tank, and the expander unit is connected to the third port at the top of the gas storage tank.

3. The system according to claim 2, characterized in that, The compressed air energy storage device also includes a control unit and a liquid level sensor; The liquid level sensor is installed inside the gas storage tank. The liquid level sensor is communicatively connected to the control unit. The control unit is communicatively connected to both the compressor unit and the expander unit.

4. The system according to claim 2, characterized in that, The gas storage facility includes multiple sub-gas storage facilities connected in series.

5. The system according to claim 4, characterized in that, Each sub-gas storage unit has a first port at its bottom; each sub-gas storage unit has a second port at its top, and all second ports are connected in parallel to the compressor unit; each sub-gas storage unit has a third port at its top, and all third ports are connected in parallel to the expander unit.

6. The system according to claim 2, characterized in that, A ball valve is installed on the waterway connecting the first waterway to the first port.

7. The system according to claim 2, characterized in that, A check valve is installed on the gas line connecting the compressor unit to the second port.

8. The system according to claim 2, characterized in that, A gate valve is installed on the air line connecting the expander unit and the third port.

9. The system according to claim 2, characterized in that, The compressed air energy storage device also includes a heat exchange unit, which is connected to the expander unit and the compressor unit respectively.

10. The system according to claim 1, characterized in that, The pressure stabilizing unit includes a pressure regulating well.

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