Flexible water pumping compressed air energy storage device

Abstract

The utility model relates to the technical field of energy storage, in particular to a flexible water pumping and compressed air energy storage device which comprises a water storage pond, a reversible pump turbine, a water-gas co-containing cabin and a compressor. The water storage tank is connected with one end of the reversible pump turbine through a first pipeline, and the other end of the reversible pump turbine is connected with the water-gas co-containing cabin through a second pipeline; the compressor is connected with the water-gas co-containing cabin through a third pipeline; a power generator-motor is arranged on the reversible water pump water wheel, a full-power converter is arranged on the power generator-motor, and the full-power converter is used for being connected with a power grid. The full-power converter is adopted as a connecting device between the generator motor and the power grid, all energy in the charging and discharging process passes through the full-power converter, and the whole capacity of the whole energy storage device is controllable; and the full-power converter serves as high-capacity power electronic equipment, is high in control precision and rapid in adjustment, can provide enough support for the high-proportion distributed wind / light micro-grid, and guarantees stable and safe operation of the power grid.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a flexible water-pumping compressed air energy storage device. Background Art

[0002] In recent years, the use of renewable energy such as wind power and photovoltaic power generation has gradually developed. However, due to their intermittent and volatile nature that is not controlled by humans, it has become a certain obstacle to their further vigorous development.

[0003] Based on the above situation, a method of storing energy by pumping water and compressing air has emerged. Water is injected into the water-gas co-containment chamber through a water pump, which is equivalent to building a virtual dam between the downstream water storage tank and the pressure vessel connected to the water pump. By controlling the air pressure in the water-gas co-containment chamber, the drop between the upstream and downstream of the virtual dam can be changed, thereby storing excess electricity. When discharging, the water in the water-gas co-containment chamber drives the turbine to rotate to generate electricity, and then releases the stored energy for use. This method has certain positive significance, but it also has certain disadvantages. For example, the motor part still uses traditional asynchronous motors and synchronous generators. When in the energy storage stage, the combination of high-pressure water pumps and asynchronous motors leads to a constant input power value for the entire device system, which is not adjustable and cannot meet the ever-changing regulation needs of the power grid, and the regulation performance is very poor. Utility Model Content

[0004] In order to solve the above technical problems or partially solve the above technical problems, the present application provides a flexible water-pumping compressed air energy storage device.

[0005] The present application provides a flexible water-pumping compressed air energy storage device, comprising a water storage tank, a reversible pump-turbine, a water-gas co-containment tank and a compressor; the water storage tank is connected to one end of the reversible pump-turbine through a first pipe, and the other end of the reversible pump-turbine is connected to the water-gas co-containment tank through a second pipe; the compressor is connected to the water-gas co-containment tank through a third pipe; the reversible pump-turbine is provided with a generator-motor, the generator-motor is provided with a full-power converter, and the full-power converter is used to connect to the power grid to ensure that the power quality frequency is maintained at the required 50Hz.

[0006] Optionally, the generator-motor is a synchronous motor.

[0007] Optionally, the stator of the generator-motor is connected to the full-power converter.

[0008] Optionally, a regulating branch is provided on the second pipeline, one end of the regulating branch is connected to the second pipeline, and the other end is connected to the water-gas co-containing chamber.

[0009] Optionally, a steam generator is provided on the regulating branch.

[0010] Optionally, a first throttle valve is provided on the second pipeline, and a second throttle valve is provided on the regulating branch.

[0011] Optionally, the full-power converter is connected to the power grid via a connecting bus, and the connecting bus is used to be electrically connected to a load to supply power to the load; the connecting bus is also used to be electrically connected to a distributed wind / solar microgrid.

[0012] Optionally, a first transformer is provided between the interconnecting bus and the full-power converter.

[0013] Optionally, the compressor is provided with an electric motor for driving the compressor to operate, and the electric motor is connected to the power grid.

[0014] Optionally, a sprinkler head is provided at one end of the regulating branch connected to the water-gas co-containment chamber.

[0015] Compared with the prior art, the technical solution provided by the embodiments of the present application has the following advantages:

[0016] The flexible pumping compressed air energy storage device provided by the present application adopts a full-power converter as a connecting device between the generator motor and the power grid. All the energy in the charging and discharging process passes through the full-power converter, and the entire energy storage device is fully controllable; and the full-power converter, as a large-capacity power electronic device, has high control accuracy, rapid adjustment, and fast response speed, and can provide sufficient support for high-proportion distributed wind / light microgrids to ensure stable and safe operation of the power grid; and under the action of the full-power converter, the mechanical speed and electrical speed of the generator-motor are completely decoupled and can also operate, that is, to ensure that the output or input of the generator-motor is always the power frequency, that is, 50Hz (electrical speed), and the reversible pump turbine can also achieve the optimal speed. Thus, the energy storage device is always at the highest efficiency under the corresponding different complex operating conditions to reduce the loss in the energy storage and release process. At the same time, by constantly changing the mechanical speed of the system, adapting to the constantly changing complex working conditions, significantly reducing the pressure pulsation, and improving the life of the entire system device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0019] Figure 1 This is a schematic diagram of the flexible pumping compressed air energy storage principle described in the embodiment of the present application;

[0020] Figure 2 This is a schematic diagram of the structure of the flexible water-pumping compressed air energy storage device described in an embodiment of the present application.

[0021] in,

[0022] 1. Water storage tank; 10. First pipeline; 100. Energy storage device; 11. Second pipeline; 12. Regulating branch; 13. Steam generator; 14. First transformer; 15. Second transformer; 16. Second throttle valve; 17. Interconnecting bus; 2. Reversible pump turbine; 3. Water-gas co-containment chamber; 4. Compressor; 5. Generator-motor; 6. Full-power converter; 7. Power grid; 8. Distributed wind / solar microgrid; 9. Load. DETAILED DESCRIPTION

[0023] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the scheme of the present application will be further described below. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only part of the embodiments of the present application, rather than all of the embodiments.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0026] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0027] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0028] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0029] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0030] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0031] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0032] Reference Figure 1 to Figure 2 As shown, a flexible water-pumping compressed air energy storage device provided in this embodiment includes a water storage tank 1, a reversible pump-turbine 2, a water-gas co-containment tank 3 and a compressor 4; the water storage tank 1 is connected to one end of the reversible pump-turbine 2 through a first pipe 10, and the other end of the reversible pump-turbine 2 is connected to the water-gas co-containment tank 3 through a second pipe 11; the compressor 4 is connected to the water-gas co-containment tank 3 through a third pipe; a generator-motor 5 is provided on the reversible pump-turbine, and a full-power converter 6 is provided on the generator-motor 5, and the full-power converter 6 is used to connect to the power grid 7.

[0033] Exemplarily, the water storage tank 1 can be open, and can be dug on site and rebuilt in the actual process; the water-gas co-containment chamber 3 is a high-pressure sealing structure to ensure that the specified pressure change can be achieved.

[0034] In addition, when the reversible pump-turbine 2 acts as a water pump, that is, when it pumps water into the water-gas co-containment chamber 3, its power source is the surplus electric energy in the power grid 7; and when the reversible pump-turbine 2 acts as a water turbine, that is, when water flows from the water-gas co-containment chamber 3 through the reversible pump-turbine 2 into the water storage tank 1, the electric energy it generates will be transmitted to the power grid 7.

[0035] The present application adopts a full-power converter 6 as a connection device between the generator-motor 5 and the power grid 7. All energy consumption or power generation capacity in the system passes through the full-power converter 6, and the entire energy storage device 100 is fully controllable; and the full-power converter 6 is a large-capacity power electronic device with high control accuracy, rapid adjustment, and fast response speed. It can provide sufficient support for the high-proportion distributed wind / light microgrid 8 to ensure the stable and safe operation of the power grid 7; and under the action of the full-power converter 6, the mechanical speed and electrical speed of the generator-motor 5 can be completely decoupled and can also operate, that is, to ensure that the output or input of the generator-motor 5 is always the power frequency (electrical speed), and the reversible pump turbine 2 can also achieve the optimal speed. Thereby, the energy storage device 100 is always at the highest efficiency under the corresponding different complex operating conditions to reduce the loss in the process of energy storage and release. At the same time, by constantly changing the mechanical speed of the system, adapting to the constantly changing complex working conditions, significantly reducing the pressure pulsation, and improving the life of the entire system device.

[0036] It should be noted that the use of a generator-motor 5 instead of a combination of a large synchronous motor and an asynchronous motor, and the use of a reversible pump-turbine 2 instead of a traditional pump-turbine combination can reduce the cost of the energy storage device 100 and save floor space.

[0037] This application has a fast response capability of seconds or even milliseconds in both the energy release and energy storage stages, and realizes the decoupling control of input and output power and the grid 7 frequency. Therefore, it can be well applied to participate in the grid 7 frequency regulation and improve the system frequency stability. By additionally controlling the outer loop power control command and adding a virtual inertia control link, the device can also have a certain inertia support capability.

[0038] In addition, for some layered and partitioned power grids 7, once the main interconnection line fails, it may cause a local isolated network phenomenon, causing frequency stability problems in the local power grid. The present application can achieve large-scale power regulation both in the energy release stage and in the energy storage stage. If supplemented by certain control strategies, it can be used to participate in the emergency frequency control of the power grid 7, that is, after the frequency drops or rises to a certain limit, the power can be adjusted in real time to change the frequency of the power grid 7 to 50Hz, which plays a beneficial role in restoring the frequency of the power grid 7.

[0039] In some further embodiments, the generator-motor 5 is a synchronous motor; and the stator of the generator-motor 5 is connected to the full power converter 6 .

[0040] In some further embodiments, a regulating branch 12 is provided on the second pipeline 11, one end of the regulating branch 12 is connected to the second pipeline 11, and the other end is connected to the water-vapor containing tank 3; a steam generator 13 is also provided on the regulating branch 12 for adjusting the pressure of the water-vapor containing tank 3.

[0041] In some further embodiments, a first throttle valve is provided on the second pipeline 11 , and a second throttle valve 16 is provided on the regulating branch 12 ; the first throttle valve is used to control the on-off of the second pipeline 11 , and the second throttle valve 16 is used to control the on-off of the regulating branch 12 .

[0042] In some further embodiments, the full-power converter 6 is connected to the power grid 7 via a connecting bus 17, and the connecting bus 17 is used to be electrically connected to the load 9 to supply power to the load 9; the connecting bus 17 is also used to be electrically connected to the distributed wind / solar microgrid 8.

[0043] It should be noted that the distributed wind / solar microgrid 8 represents a distributed wind energy microgrid and a distributed solar energy microgrid.

[0044] Specifically, the interconnecting bus 17 is similar to the main grid, the load 9, the power grid 7, and the distributed wind / photovoltaic microgrid 8 are all electrically connected to the interconnecting bus 17, and a first transformer 14 is provided between the interconnecting bus 17 and the full-power converter 6; a second transformer 15 is connected between the load 9, the distributed wind / photovoltaic microgrid 8 and the interconnecting bus 17.

[0045] In some further embodiments, the compressor 4 is provided with an electric motor for driving the compressor 4 to operate, and the electric motor is connected to the power grid 7; the electric motor drives the compressor 4 to move so as to inflate the water-gas co-containment chamber 3 to provide pressure.

[0046] In some further embodiments, a spray head is provided at one end of the regulating branch 12 connected to the water-vapor co-containment chamber 3; the spray head is used to spray water entering the water-vapor co-containment chamber 3 over a larger area, thereby more fully exchanging heat with the compressed gas to reduce the temperature change during the compression process, thereby avoiding affecting the pressure of the water-vapor co-containment chamber 3.

[0047] It should be noted that the capacity of the full-power converter 6 can usually be between 50 and 100 MW, and can be specifically applied to small and medium-capacity pumped compressed air energy storage devices.

[0048] The whole device consists of the following three stages.

[0049] Preset stage: Before the system starts working, a certain amount of gas is filled into the water-gas co-containment chamber 3 by using the compressor 4 to make the internal pressure reach the preset pressure, that is, to create a high-pressure environment at the water-gas interface. After that, the compressor 4 is only used to supplement the internal air leakage of the system and no longer participates in the energy storage and release of the system.

[0050] Energy storage stage: Use the reversible pump turbine 2 and the generator-motor 5 to fill water into the water-gas co-containment chamber 3. As the gas part is compressed, the temperature will slowly rise, and a part of the water is sprayed into the interior through the spray head, accelerating the heat exchange between the water and the gas part, adjusting the temperature inside the water-gas co-containment chamber 3, so as to keep the internal pressure constant.

[0051] Energy release stage: the water inside the water-gas co-containment chamber 3 is released, and power is generated by the reversible water pump turbine 2 and the generator-motor 5. In the process of compressed air pushing water outward to do work, the expansion of the gas will cause the gas temperature and pressure to decrease. At this time, high-pressure steam is introduced into the water-gas co-containment chamber 35 to compensate for the decrease in gas pressure.

[0052] The above is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features applied for herein.

Claims

1. A flexible pumped compressed air energy storage device, characterized in that: The invention comprises a water storage tank (1), a reversible pump turbine (2), a water-gas co-containment tank (3) and a compressor (4); the water storage tank (1) is connected to one end of the reversible pump turbine (2) via a first pipeline (10), and the other end of the reversible pump turbine (2) is connected to the water-gas co-containment tank (3) via a second pipeline (11); the compressor (4) is connected to the water-gas co-containment tank (3) via a third pipeline; the reversible pump turbine is provided with a generator-motor (5), the generator-motor (5) is provided with a full-power converter (6), and the full-power converter (6) is used to be connected to a power grid (7).

2. The flexible pumped compressed air energy storage device according to claim 1, characterized in that: The generator-motor (5) is a synchronous motor.

3. The flexible pumped compressed air energy storage device according to claim 2, characterized in that: The stator of the generator-motor (5) is connected to the full-power converter (6).

4. The flexible pumped compressed air energy storage device according to claim 1, characterized in that: The second pipeline (11) is provided with a regulating branch (12), one end of the regulating branch (12) is connected to the second pipeline (11), and the other end is connected to the water-gas co-accommodation chamber (3).

5. The flexible pumped compressed air energy storage device according to claim 4, characterized in that: The regulating branch (12) is provided with a steam generator (13).

6. The flexible pumped compressed air energy storage device according to claim 4, characterized in that: The second pipeline (11) is provided with a first throttle valve, and the regulating branch (12) is provided with a second throttle valve (16).

7. The flexible pumped compressed air energy storage device according to claim 1, characterized in that: The full-power converter (6) is connected to the power grid (7) via a connecting bus (17), and the connecting bus (17) is used to be electrically connected to a load (9) to supply power to the load (9); the connecting bus (17) is also used to be electrically connected to a distributed wind / solar microgrid (8).

8. The flexible pumped compressed air energy storage device according to claim 7, characterized in that: A first transformer (14) is provided between the interconnecting bus (17) and the full-power converter (6).

9. The flexible pumped compressed air energy storage device according to claim 1, characterized in that: The compressor (4) is provided with an electric motor for driving the compressor (4) to operate, and the electric motor is connected to the power grid (7).

10. The flexible pumped compressed air energy storage device according to claim 4, characterized in that: A spray head is provided at one end of the regulating branch (12) connected to the water-gas co-accommodation chamber (3).

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