Compressed air energy storage and pumped hydro energy storage coupled variable voltage constant pressure operation system and method

Abstract

The present invention provides a system and method for coupled variable pressure constant pressure operation of compressed air energy storage and pumped storage, comprising a compressed air energy storage system, a pumped storage system, a water pipeline, and an automatic waterway shut-off valve; the energy storage bin of the compressed air energy storage system is connected to the lower reservoir of the pumped storage power station of the pumped storage system through a water pipeline, and an automatic waterway shut-off valve is installed on the water pipeline, so that the energy storage bin of the compressed air energy storage system is hydraulically connected to the upper reservoir of the pumped storage power station through the water diversion system of the pumped storage power station, thereby realizing variable pressure and / or constant pressure operation of the compressed air energy storage system. This method can realize the two-stage operation of compressed air energy storage with variable pressure + constant pressure, improve the energy storage efficiency, greatly reduce the space required for the compressed air energy storage bin, and significantly reduce the investment cost of compressed air energy storage. At the same time, through the adjustment of the pipeline valve, the energy storage bin can realize the function of an air cushion-type pressure regulating well of the pumped storage power station.

Description

Technical Field

[0001] The present invention relates to the technical field of compressed air energy storage, and in particular to a system and method for coupling compressed air energy storage with pumped storage to operate at a variable pressure and constant pressure. Background Art

[0002] With the development of compressed air energy storage technology, artificial gas storage chambers have the advantages of easy site selection, flexible capacity setting, safety and reliability. However, due to the influence of the charging and discharging efficiency of compressed air energy storage, the operating pressure of the gas storage chamber must be in the high-pressure operating range, which results in the need for a larger gas storage space in the gas storage chamber and the existence of low gas pads. In addition, the expander operating mode is variable pressure operation, which reduces the electricity-to-electricity conversion efficiency to a certain extent. Summary of the Invention

[0003] In response to the defects of the existing technology, the present invention provides a system and method for coupling compressed air energy storage and pumped storage with variable pressure constant pressure operation, which can effectively solve the above problems.

[0004] The technical solution adopted in the present invention is as follows:

[0005] The present invention provides a compressed air energy storage and pumped water energy storage coupled variable pressure constant pressure operation system, comprising a compressed air energy storage system, a pumped water energy storage system, a water pipeline (2) and a waterway automatic shut-off valve (4);

[0006] The energy storage bin (1) of the compressed air energy storage system is connected to the lower reservoir (14) of the pumped storage power station of the pumped storage system through the water transmission pipeline (2), and the waterway automatic shut-off valve (4) is installed on the water transmission pipeline (2), so that the energy storage bin (1) of the compressed air energy storage system is hydraulically connected to the upper reservoir (16) of the pumped storage power station through the water diversion system (3) of the pumped storage power station, thereby realizing the variable pressure and / or constant pressure operation of the compressed air energy storage system.

[0007] Preferably, the energy storage tank (1) of the compressed air energy storage system forms a constant water level difference that meets the requirements with the water level of the upper reservoir (16) of the pumped storage power station of the pumped water energy storage system.

[0008] Preferably, the compressed air energy storage system comprises the energy storage bin (1), an air transmission pipeline (9), an inflation airway valve (10), a deflation airway valve (11), a compressor (12) and an expander (13);

[0009] A flexible water-gas separation layer (6) is provided in the energy storage bin (1), and the flexible water-gas separation layer (6) changes adaptively with the water level in the energy storage bin (1); the energy storage bin (1) has a gas storage side and a water storage side through the flexible water-gas separation layer (6); the gas storage side is connected to one end of the gas transmission pipeline (9); the other end of the gas transmission pipeline (9) is connected in parallel to a first gas transmission branch pipe and a second gas transmission branch pipe, the first gas transmission branch pipe is provided with the compressor (12) and the inflation airway valve (10); the second gas transmission branch pipe is provided with the expander (13) and the deflation airway valve (11).

[0010] Preferably, sensors for detecting air pressure, temperature and liquid level are provided in the energy storage bin (1).

[0011] Preferably, a heat exchange system (14) is installed between the compressor (12) and the expander (13).

[0012] Preferably, the pumped storage energy system comprises a pumped storage power station water diversion system (3), a pumped storage power station underground powerhouse (15), an upper reservoir of the pumped storage power station (16), a water pressure sensor (17), a tailwater system of the pumped storage power station (18) and a lower reservoir of the pumped storage power station (19);

[0013] Through the pumped storage power station water diversion system (3), the connection between the pumped storage power station upper reservoir (16), the pumped storage power station lower reservoir (19), the pumped storage power station underground powerhouse (15) and the pumped storage power station tailwater system (18) is achieved according to the water flow from top to bottom; the water pressure sensor (17) is installed in the water diversion pipeline between the pumped storage power station underground powerhouse (15) and the pumped storage power station tailwater system (18).

[0014] The present invention also provides an operating method of the compressed air energy storage and pumped water storage coupled variable pressure constant pressure operating system, comprising the following steps:

[0015] By controlling the opening and closing of the waterway automatic shutoff valve (4) installed in the water pipeline (2), various charging and discharging combinations of the compressed air energy storage system and the pumped water storage system are realized;

[0016] Among them, the compressed air energy storage system has three operating modes, namely: compressed air energy storage system variable pressure operation mode, compressed air energy storage system pure constant pressure operation mode, and compressed air energy storage system variable pressure coupling constant pressure operation mode.

[0017] Preferably, in the variable pressure operation mode of the compressed air energy storage system, the waterway automatic shut-off valve (4) is always in a closed state, comprising the following steps:

[0018] Step A1, initial state of the energy storage bin: the energy storage bin (1) is empty, and the gas storage pressure is atmospheric pressure;

[0019] Step A2, initializing energy storage in the energy storage bin: the air duct valve (10) is opened, the compressor (12) is started, and compressed air enters the energy storage bin (1) until the air pressure in the energy storage bin (1) reaches the maximum design pressure, the air duct valve (10) is closed, and the compressor (12) is turned off;

[0020] Step A3: First energy release of the energy storage bin:

[0021] During peak electricity demand periods or when the grid is short of power, the compressed air energy storage system starts generating electricity:

[0022] The first stage of power generation: the deflation airway valve (11) is opened, and the compressed air in the energy storage bin (1) flows into the expander (13). The gas expansion drives the expander (13) to generate electricity. The expander (13) operates in a throttling mode, and most of the air flow enters the first-stage expander. The expander (13) drives the generator to generate power. During the power generation process of the expander (13), the compressed air in the energy storage bin (1) gradually decreases, and the air pressure in the energy storage bin (1) gradually decreases.

[0023] The second stage of power generation: when the pressure of the energy storage bin (1) drops to the lower limit of the rated operating pressure of the first cylinder of the expander, the air supply mode is adopted, the second stage regulating valve of the expander is opened, and most of the air flow enters the second and third stages of the expander. At this time, it is in the air supply state, and the pressure-changing operation power generation stage of the expander (13) is completed until the pressure in the energy storage bin (1) reaches the design lower limit pressure, the air vent valve (11) is closed, and power generation ends;

[0024] Step A4: Second energy storage in the energy storage warehouse:

[0025] During off-peak hours when there is excess electricity supply, the compressed air energy storage system starts charging;

[0026] The inflation airway valve (10) is opened, the compressor (12) is started, and compressed air enters the energy storage bin (1). At this time, the air in the energy storage bin (1) is in a pressurization process. When the air pressure in the energy storage bin (1) reaches the maximum design pressure, the inflation airway valve (10) is closed, and the compressor (12) stops working, completing energy storage;

[0027] Steps A3 and A4 are repeated in a cycle to realize the variable pressure operation of the compressed air energy storage system.

[0028] Preferably, the compressed air energy storage system pure constant pressure operation mode includes the following steps:

[0029] Step B1, the energy storage bin is in the original state: the energy storage bin (1) is empty and the gas storage pressure is atmospheric pressure;

[0030] Step B2, initializing energy storage in the energy storage bin: the air duct valve (10) is opened, the compressor (12) is started, compressed air enters the energy storage bin (1), and the air pressure in the energy storage bin (1) continuously increases. When the air pressure in the energy storage bin (1) is the same as the water pressure monitored by the water pressure sensor (17), the air duct valve (10) is closed, and the compressor (12) is turned off;

[0031] Step B3: First energy release of the energy storage bin:

[0032] During peak electricity demand periods or when the grid is short of power, the compressed air energy storage system starts generating electricity:

[0033] The automatic shutoff valve (4) of the waterway is opened, and water from the upper reservoir (16) of the pumped storage power station enters the energy storage bin (1) through the water diversion system (3) of the pumped storage power station. The air vent valve (11) is opened, and the compressed air in the energy storage bin (1) flows into the expander (13). The gas expands and drives the expander (13) to generate electricity. Since the head difference is substantially constant, the expander (13) performs constant pressure expansion to perform work and discharge.

[0034] After the water level in the energy storage bin (1) reaches the designed maximum water level (7) of the energy storage bin, the waterway automatic shutoff valve (4) automatically closes, the air vent valve (11) closes, and the energy release is completed, thus achieving the constant pressure operation power generation stage of the expander (13);

[0035] Step B 4: Second energy storage in the energy storage bin:

[0036] During off-peak hours when there is excess electricity supply, the compressed air energy storage system activates its energy storage function;

[0037] The air inflatable airway valve (10) is opened, the waterway automatic shut-off valve (4) is opened, and the compressor (12) starts to work, continuously compressing air into the energy storage bin (1), and the water in the energy storage bin (1) is gradually pressed into the upper reservoir (16) of the pumped storage power station. When the water level in the energy storage bin (1) reaches the designed minimum water level (8) of the energy storage bin, the compressor (12) stops working, and energy storage is completed;

[0038] Steps B3 and B4 are cycled to achieve pure constant pressure operation of the compressed air energy storage system.

[0039] Preferably, the compressed air energy storage system variable pressure coupling constant pressure operation mode includes the following steps:

[0040] Step C1, the energy storage bin is in the original state: the energy storage bin (1) is empty, and the gas storage pressure is atmospheric pressure;

[0041] Step C2, initializing energy storage in the energy storage bin: the air duct valve (10) is opened, the compressor (12) is started, and compressed air enters the energy storage bin (1) until the air pressure in the energy storage bin (1) reaches the maximum design pressure, the air duct valve (10) is closed, and the compressor (12) is turned off;

[0042] Step C3: First energy release of the energy storage bin:

[0043] During peak electricity demand periods or when the grid is short of power, the compressed air energy storage system starts generating electricity:

[0044] The first stage of power generation: the deflation airway valve (11) is opened, and the compressed air in the energy storage bin (1) flows into the expander (13). The gas expansion drives the expander (13) to generate electricity. The expander (13) operates in a throttling mode, and most of the air flow enters the first-stage expander. The expander (13) drives the generator to generate power. During the power generation process of the expander (13), the compressed air in the energy storage bin (1) gradually decreases, and the air pressure in the energy storage bin (1) gradually decreases.

[0045] The second stage of power generation: when the pressure of the energy storage bin (1) drops to the lower limit of the rated operating pressure of the first cylinder of the expander, the expander is operated in an air supply mode, the second stage regulating valve of the expander is opened, and most of the air flow enters the second and third stages of the expander. At this time, the expander is in an air supply state, and the pressure-changing operation power generation stage of the expander (13) is completed;

[0046] In the third stage of power generation, as power generation in the second stage is completed, the air pressure in the energy storage bin (1) continuously decreases. When the air pressure in the energy storage bin (1) is the same as the water pressure monitored by the water pressure sensor (17), the waterway automatic shutoff valve (4) opens, and water from the upper reservoir (16) of the pumped storage power station enters the energy storage bin (1) through the water diversion system (3) of the pumped storage power station. The energy storage bin (1) realizes a water-gas co-containment type, and the expander (13) performs constant pressure expansion to perform work discharge.

[0047] When the water level in the energy storage bin (1) reaches the designed maximum water level (7) of the energy storage bin, the waterway automatic shutoff valve (4) automatically closes, the air vent valve (11) closes, and the discharge stops, thus achieving the constant pressure operation power generation stage of the expander (13);

[0048] Step C4: The energy storage bin is charged and stored for the second time.

[0049] During off-peak hours when electricity supply is in excess, the compressed air energy storage system starts the charging and energy storage function.

[0050] The first stage of charging: the air duct valve (10) is opened, and the compressor (12) starts working. When the storage gas pressure of the energy storage bin is greater than or equal to the water head differential pressure, the waterway automatic shut-off valve (4) is opened, and the air is continuously compressed into the energy storage bin (1). The water in the energy storage bin (1) is gradually pressed into the upper reservoir (16) of the pumped storage power station. When the water level in the energy storage bin (1) reaches the designed minimum water level (8) of the energy storage bin, the compressor (12) stops working, and the waterway automatic shut-off valve (4) is closed.

[0051] Second stage of charging: After the waterway automatic shut-off valve (4) is closed, the compressor (12) continues to work, and the air in the energy storage bin (1) is in a pressurized process. When the air pressure in the energy storage bin (1) reaches the maximum design pressure, the airway valve (10) is closed, and the compressor (12) stops working, completing energy storage;

[0052] Step C3 and step C4 are circulated to realize the coupled operation of variable pressure and constant pressure of the compressed air energy storage system.

[0053] The system and method for coupled variable pressure constant pressure operation of compressed air energy storage and pumped water storage provided by the present invention have the following advantages:

[0054] 1) By setting up a water transmission channel to establish hydraulic connection with the upper reservoir of the pumped storage power station, the constant pressure operation of the expansion system can be achieved, the charging and discharging efficiency can be improved, and at the same time, the capacity of the energy storage warehouse can be significantly reduced under the same power condition, which reduces the construction cost.

[0055] 2) By installing an automatic shut-off valve on the water supply channel, the energy storage tank can operate independently, allowing the expander to operate at variable pressure. Combined with the beneficial effect of 1), the expander can operate at variable pressure + constant pressure, maximizing the capacity of the energy storage tank.

[0056] 3) By controlling the automatic shut-off valve on the water channel, the energy storage tank can be used as an air cushion surge well of the pumped storage power station, maximizing the functional utilization of the energy storage tank and reducing the cost of the pumped storage power station. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a structural diagram of the compressed air energy storage and pumped storage coupled variable pressure constant pressure operation system provided by the present invention.

[0058] Among them: 1-energy storage tank; 2-water transmission pipeline; 3-pumped storage power station water diversion system; 4-water channel automatic shut-off valve; 5-air pressure / temperature / liquid level sensor; 6-flexible water-gas separation layer; 7-energy storage tank design maximum water level; 8-energy storage tank design minimum water level; 9-gas transmission pipeline; 10-inflating airway valve; 11-deflation airway valve; 12-compressor; 13-expander; 14-heat exchange system; 15-pumped storage power station underground plant; 16-upper reservoir of pumped storage power station; 17-water pressure sensor; 18-tailwater system of pumped storage power station; 19-lower reservoir of pumped storage power station. DETAILED DESCRIPTION

[0059] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to 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 intended to limit the present invention.

[0060] Based on existing compressed air energy storage technology, this invention proposes an operating method that utilizes the high-level head difference of a pumped-storage power station to drive the remaining gas in the gas storage reservoir to perform work. This method effectively achieves variable-pressure and constant-pressure operation of the compressed air energy storage expansion system, improving efficiency while significantly reducing the size of underground energy storage silos. Simultaneously, the principle of automatic control of waterway valves is utilized to realize the function of an air-cushioned surge tank in the energy storage silo. This invention has practical significance both in terms of reducing the size of gas storage silos and reducing construction costs through the use of compressed air energy storage technology, and in terms of improving the conversion efficiency of compressed air energy storage power stations.

[0061] See Figure 1 The present invention provides a compressed air energy storage and pumped water storage coupled variable pressure constant pressure operation system, which is based on actual engineering and includes a compressed air energy storage system, a pumped water storage system, a water pipeline 2 and a waterway automatic shut-off valve 4;

[0062] The energy storage bin 1 of the compressed air energy storage system is connected to the lower reservoir 14 of the pumped storage power station of the pumped water energy storage system through the water pipeline 2. The waterway automatic shut-off valve 4 is installed on the water pipeline 2, so that the energy storage bin 1 of the compressed air energy storage system is hydraulically connected to the upper reservoir 16 of the pumped storage power station through the water diversion system 3 of the pumped storage power station. By controlling the closing and opening of the automatic shut-off valve 4 of the waterway, the variable pressure and / or constant pressure operation of the compressed air energy storage system is achieved. The variable pressure and constant pressure here refer to the pressure changes in the energy storage bin 1.

[0063] In the present invention, the water pipeline 2 is connected to the pumped-storage power station water diversion system 3 at the bottom, and the energy storage tank 1 can utilize the net head pressure of the upper reservoir; the energy storage tank 1 can also be directly hydraulically connected to the upper reservoir through the water pipeline 2. For example, the energy storage tank 1 of the compressed air energy storage system is located at the bottom of the entire system and is hydraulically connected to the pumped-storage power station upper reservoir 16 through the pumped-storage power station water diversion system 3. It also forms a constant and required water level difference with the water level of the pumped-storage power station upper reservoir 16 of the pumped-storage power station system.

[0064] As a specific implementation, the compressed air energy storage system includes the energy storage bin 1, the gas transmission pipeline 9, the inflation airway valve 10, the deflation airway valve 11, the compressor 12 and the expander 13;

[0065] A flexible water-vapor separation layer 6 is provided in the energy storage bin 1, and the flexible water-vapor separation layer 6 adaptively changes with the water level in the energy storage bin 1; through the flexible water-vapor separation layer 6, the energy storage bin 1 has an air storage side and a water storage side; by providing a flexible water-vapor separation layer 6 on the inner wall of the energy storage bin 1, the air and water in the energy storage bin 1 are completely isolated during the process of filling and discharging air / draining water, thereby avoiding excessive humidity in the air.

[0066] The gas storage side is connected to one end of the gas pipeline 9; the other end of the gas pipeline 9 is connected in parallel to a first gas branch pipe and a second gas branch pipe. The first gas branch pipe is provided with the compressor 12 and the inflation airway valve 10; the second gas branch pipe is provided with the expander 13 and the deflation airway valve 11. Sensors for detecting air pressure, temperature, and liquid level are provided in the energy storage bin 1 and are located at the top of the energy storage bin 1 to monitor changes in the liquid level / air pressure / temperature in the energy storage bin 1 in real time. A heat exchange system 14 is installed between the compressor 12 and the expander 13.

[0067] As a specific implementation, the pumped storage system includes a pumped storage power station water diversion system 3, a pumped storage power station underground powerhouse 15, a pumped storage power station upper reservoir 16, a water pressure sensor 17, a pumped storage power station tailwater system 18 and a pumped storage power station lower reservoir 19;

[0068] Through the pumped-storage power station water diversion system 3, the connection between the upper reservoir 16 of the pumped-storage power station, the lower reservoir 19 of the pumped-storage power station, the underground powerhouse 15 of the pumped-storage power station and the tail water system 18 of the pumped-storage power station is realized according to the water flow from top to bottom; the water pressure sensor 17 is installed in the water diversion pipeline between the underground powerhouse 15 of the pumped-storage power station and the tail water system 18 of the pumped-storage power station.

[0069] In actual application, the air pressure / temperature / liquid level sensor is linked with the compressor 12, the expander 13 and the automatic water shut-off valve 4. When the sensor reaches the set value and transmits it to the system control, the compressor 12, the expander 13 and the automatic water shut-off valve 4 are automatically closed or opened according to the instructions.

[0070] By regulating the opening and closing of the system's automatic waterway shutoff valve 4, various charging and discharging combinations of compressed air energy storage and pumped hydro energy storage can be achieved. The automatic waterway shutoff valve 4 is regulated to open and close based on changes in the liquid level and air pressure within the energy storage bin 1.

[0071] The present invention discloses a system and method for operating compressed air energy storage and pumped storage coupled with voltage conversion and constant pressure. It is a system and method for operating compressed air energy storage power station and pumped storage power station in a deep coupled voltage conversion and constant pressure phased manner. By setting a water pipeline, the energy storage bin in the compressed air energy storage system is hydraulically connected to the upper reservoir of the pumped storage power station through the pumped storage water diversion system. An automatic waterway shut-off valve is set between the water pipeline and the energy storage bin, and a flexible water-gas separation layer is set in the energy storage bin to achieve water-gas co-containment and separation. This method can realize the two-stage operation of compressed air energy storage with voltage conversion and constant pressure, improve the energy storage efficiency, greatly reduce the space required for the compressed air energy storage bin, and greatly reduce the investment cost of compressed air energy storage. At the same time, through the adjustment of the pipeline valve, the energy storage bin (water-gas co-containment bin) can realize the function of the air cushion type pressure regulating well of the pumped storage power station.

[0072] The present invention also provides an operating method for a compressed air energy storage and pumped water energy storage coupled variable pressure constant pressure operating system, comprising the following steps:

[0073] By controlling the opening and closing of the automatic shut-off valve 4 installed in the water pipeline 2, various charging and discharging combinations of the compressed air energy storage system and the pumped storage system can be realized;

[0074] Among them, the compressed air energy storage system has three operating modes, namely: compressed air energy storage system variable pressure operation mode, compressed air energy storage system pure constant pressure operation mode, and compressed air energy storage system variable pressure coupling constant pressure operation mode.

[0075] The compressed air energy storage system operates in variable pressure mode, with the waterway automatic shutoff valve 4 always in a closed state, including the following steps:

[0076] Step A1, initial state of energy storage bin: energy storage bin 1 is empty, and the gas storage pressure is atmospheric pressure;

[0077] Step A2, initializing energy storage in the energy storage bin: the air duct valve 10 is opened, the compressor 12 is started, and compressed air enters the energy storage bin 1 until the air pressure in the energy storage bin 1 reaches the maximum design pressure, the air duct valve 10 is closed, and the compressor 12 is turned off;

[0078] Step A3: First energy release of the energy storage bin:

[0079] During peak electricity demand periods or when the grid is short of power, the compressed air energy storage system starts generating electricity:

[0080] The first stage of power generation: the deflation airway valve 11 is opened, and the compressed air in the energy storage bin 1 flows into the expander 13. The gas expansion drives the expander 13 to generate electricity. The expander 13 operates in a throttling mode, and most of the air flow enters the first-stage expander. The expander 13 drives the generator to generate power. During the power generation process of the expander 13, the compressed air in the energy storage bin 1 gradually decreases, and the air pressure in the energy storage bin 1 gradually decreases.

[0081] The second stage of power generation: when the pressure of the energy storage bin 1 drops to the lower limit of the rated operating pressure of the first cylinder of the expander, the air supply mode is adopted, the second stage regulating valve of the expander is opened, and most of the air flow enters the second and third stages of the expander. At this time, it is in the air supply state, and the pressure conversion operation and power generation stage of the expander 13 is completed. Until the pressure in the energy storage bin 1 reaches the design lower limit pressure, the air vent valve 11 is closed, and power generation ends;

[0082] Step A4: Second energy storage in the energy storage warehouse:

[0083] During off-peak hours when there is excess electricity supply, the compressed air energy storage system starts charging;

[0084] The inflation airway valve 10 is opened, the compressor 12 is started, and compressed air enters the energy storage bin 1. At this time, the air in the energy storage bin 1 is in a pressurized process. When the air pressure in the energy storage bin 1 reaches the maximum design pressure, the inflation airway valve 10 is closed, the compressor 12 stops working, and energy storage is completed.

[0085] Steps A3 and A4 are repeated in a cycle to realize the variable pressure operation of the compressed air energy storage system.

[0086] The pure constant pressure operation mode of the compressed air energy storage system includes the following steps:

[0087] Step B1, the original state of the energy storage bin: the energy storage bin 1 is empty, and the gas storage pressure is atmospheric pressure;

[0088] Step B2, initializing energy storage in the energy storage bin: the air duct valve 10 is opened, the compressor 12 is started, compressed air enters the energy storage bin 1, and the air pressure in the energy storage bin 1 continuously increases. When the stored air pressure in the energy storage bin 1 is the same as the water pressure monitored by the water pressure sensor 17, the air duct valve 10 is closed, and the compressor 12 is turned off;

[0089] Step B3: First energy release of the energy storage bin:

[0090] During peak electricity demand periods or when the grid is short of power, the compressed air energy storage system starts generating electricity:

[0091] The automatic shut-off valve 4 of the waterway is opened, and the water from the upper reservoir 16 of the pumped-storage power station enters the energy storage tank 1 through the water diversion system 3 of the pumped-storage power station. The venting airway valve 11 is opened, and the compressed air in the energy storage tank 1 flows into the expander 13. The gas expansion drives the expander 13 to generate electricity. Since the head difference is basically constant, the expander 13 performs constant pressure expansion and discharges work.

[0092] After the water level in the energy storage bin 1 reaches the designed maximum water level 7 of the energy storage bin, the waterway automatic shut-off valve 4 is automatically closed, the air vent valve 11 is closed, the energy release is completed, and the expander 13 enters the constant pressure operation power generation stage;

[0093] Step B 4: Second energy storage in the energy storage bin:

[0094] During off-peak hours when there is excess electricity supply, the compressed air energy storage system activates its energy storage function;

[0095] The airway valve 10 is opened, the waterway automatic shut-off valve 4 is opened, and the compressor 12 starts working, continuously compressing air into the energy storage bin 1. The water in the energy storage bin 1 is gradually pressed into the upper reservoir 16 of the pumped storage power station. When the water level in the energy storage bin 1 reaches the designed minimum water level 8 of the energy storage bin, the compressor 12 stops working, completing energy storage.

[0096] Steps B3 and B4 are cycled to achieve pure constant pressure operation of the compressed air energy storage system.

[0097] The compressed air energy storage system voltage-variable coupled constant pressure operation mode comprises the following steps:

[0098] Step C1, the original state of the energy storage bin: the energy storage bin 1 is empty, and the gas storage pressure is atmospheric pressure;

[0099] Step C2, initializing energy storage in the energy storage bin: the air duct valve 10 is opened, the compressor 12 is started, and compressed air enters the energy storage bin 1 until the air pressure in the energy storage bin 1 reaches the maximum design pressure, the air duct valve 10 is closed, and the compressor 12 is turned off;

[0100] Step C3: First energy release of the energy storage bin:

[0101] During peak electricity demand periods or when the grid is short of power, the compressed air energy storage system starts generating electricity:

[0102] The first stage of power generation: the deflation airway valve 11 is opened, and the compressed air in the energy storage bin 1 flows into the expander 13. The gas expansion drives the expander 13 to generate electricity. The expander 13 operates in a throttling mode, and most of the air flow enters the first-stage expander. The expander 13 drives the generator to generate power. During the power generation process of the expander 13, the compressed air in the energy storage bin 1 gradually decreases, and the air pressure in the energy storage bin 1 gradually decreases.

[0103] The second stage of power generation: when the pressure of the energy storage tank 1 drops to the lower limit of the rated operating pressure of the first cylinder of the expander, the air supply mode is adopted, the second stage regulating valve of the expander is opened, and most of the air flow enters the second and third stages of the expander. At this time, it is in the air supply state, completing the pressure change operation and power generation stage of the expander 13;

[0104] In the third stage of power generation, as power is generated in the second stage, the air pressure in the energy storage bin 1 continues to decrease. When the stored air pressure in the energy storage bin 1 is the same as the water pressure monitored by the water pressure sensor 17, the waterway automatic shut-off valve 4 opens, and water from the upper reservoir 16 of the pumped storage power station enters the energy storage bin 1 through the pumped storage power station water diversion system 3. The energy storage bin 1 realizes a water-gas co-containment type, and the expander 13 performs constant pressure expansion to perform work and discharge.

[0105] When the water level in the energy storage bin 1 reaches the designed maximum water level 7 of the energy storage bin, the waterway automatic shut-off valve 4 is automatically closed, the air vent valve 11 is closed, the discharge is stopped, and the expander 13 enters the constant pressure operation power generation stage;

[0106] Step C4: The energy storage bin is charged and stored for the second time.

[0107] During off-peak hours when electricity supply is in excess, the compressed air energy storage system starts the charging and energy storage function.

[0108] The first stage of charging: the airway valve 10 is opened, and the compressor 12 starts working. When the storage gas pressure in the energy storage bin is greater than or equal to the water head differential pressure, the waterway automatic shut-off valve 4 opens, and the air is continuously compressed into the energy storage bin 1. The water in the energy storage bin 1 is gradually pressed into the upper reservoir 16 of the pumped storage power station. When the water level in the energy storage bin 1 reaches the designed minimum water level 8 of the energy storage bin, the compressor 12 stops working, and the waterway automatic shut-off valve 4 closes.

[0109] The second stage of charging: After the automatic shut-off valve 4 of the water channel is closed, the compressor 12 continues to work. At this time, the air pressure in the energy storage bin 1 is in the process of increasing. When the air pressure in the energy storage bin 1 reaches the maximum design pressure, the inflation airway valve 10 is closed, the compressor 12 stops working, and energy storage is completed;

[0110] Step C3 and step C4 are circulated to realize the coupled operation of variable pressure and constant pressure of the compressed air energy storage system.

[0111] An embodiment is described below:

[0112] Compressed air energy storage tank 1 is hydraulically connected to the upper reservoir 16 of the pumped storage power station via a water pipeline 2, enabling variable-pressure and constant-pressure operation of compressed air energy storage. The system's functionality is achieved by installing an automatic waterway shutoff valve 4 on the water pipeline 2. By controlling the automatic waterway shutoff valve 4, the system achieves coupled operation of compressed air energy storage and pumped water storage.

[0113] The compressed air energy storage system can realize three operating schemes: variable pressure operation, pure constant pressure operation, and variable pressure + constant pressure coupled operation. The operating logic of the three operating schemes is described below:

[0114] Compressed air energy storage system voltage transformation operation logic:

[0115] 1. The original state of the energy storage bin: the energy storage bin 1 is empty, the air pressure is one atmosphere, and the automatic waterway shut-off valve 4 is in the closed state.

[0116] 2. Initialize energy storage in the energy storage bin: the inflation airway valve 10 is opened, the compressor 12 is started, and compressed air enters the energy storage bin 1. The air pressure in the energy storage bin 1 continues to increase until the air pressure in the energy storage bin 1 reaches the maximum design pressure. The inflation airway valve 10 is closed, and the compressor 12 is turned off.

[0117] 3. First energy release of the energy storage warehouse: During peak power demand periods or when the power grid is short of power, the compressed air energy storage system starts generating electricity:

[0118] The first stage of power generation: the automatic shut-off valve 4 of the water channel is closed, the vent valve 11 is opened, and the compressed air in the energy storage bin 1 flows into the expander 13. The expansion of the gas drives the expander 13 to generate electricity. The expander 13 operates in a throttling mode, and most of the air flow enters the first-stage expander. The expander 13 drives the generator to generate electricity. During the power generation process of the expander 13, the compressed air in the energy storage bin 1 gradually decreases, and the air pressure in the energy storage bin 1 gradually decreases.

[0119] The second stage of power generation: After the pressure in energy storage bin 1 drops to the lower limit of the rated operating pressure of the expander's first cylinder, the system adopts the air supply mode. The second-stage regulating valve of the expander opens, and most of the air flow enters the second and third stages of the expander. This is the air supply state, completing the pressure-variable power generation phase of expander 13. The pressure in energy storage bin 1 reaches the design lower limit, and the air vent valve 11 closes, ending power generation. This process is defined as II1.

[0120] 4. Second Energy Storage: During off-peak hours with excess electricity, the compressed air energy storage system activates its charging function. Automatic waterway shutoff valve 4 remains closed, while airway valve 10 opens and compressor 12 starts operating. Compressed air enters energy storage silo 1, causing the pressure inside silo to increase. When the pressure inside silo reaches the maximum design pressure, airway valve 10 closes and compressor 12 stops, completing energy storage. This process is defined as I2.

[0121] The subsequent steps 3 and 4 are circulated to realize the variable pressure operation of the compressed air energy storage system. During the variable pressure operation of the compressed air energy storage system, the waterway automatic shut-off valve 4 must always be in the closed state.

[0122] Compressed air energy storage system pure constant pressure operation logic:

[0123] 1. Original state of energy storage bin 1: energy storage bin 1 is empty, air pressure is one atmosphere, and waterway automatic shut-off valve 4 is in closed state.

[0124] 2. Initialize energy storage in the energy storage bin: open the inflation airway valve 10, start the compressor 12, and allow compressed air to enter the energy storage bin 1. The air pressure in the energy storage bin 1 continues to rise. When the air pressure monitored by the air pressure sensor of the energy storage bin 1 equals the water pressure monitored by the water pressure sensor 17, close the inflation airway valve 10, turn off the compressor 12, and complete the initialization of energy storage.

[0125] 3. First energy release of the energy storage warehouse: During peak power demand periods or when the power grid is short of power, the compressed air energy storage system starts generating electricity:

[0126] The automatic shutoff valve 4 opens, allowing water from the pumped-storage power station's upper reservoir 16 to enter the energy storage tank 1 through the pumped-storage power station's water diversion system 3. The vent valve 11 opens, allowing compressed air within the tank 1 to flow into the expander 13. The expansion of the gas drives the expander 13 to generate electricity. Since the head difference is essentially constant, the expander 13 now performs constant-pressure expansion and discharges work. Once the liquid level sensor in the energy storage tank 1 reaches the tank's designed maximum water level 7, the automatic shutoff valve 4 closes, and the vent valve 11 closes, completing the energy release. This process completes the expander 13's constant-pressure power generation phase. This process is defined as II2.

[0127] 4. Second Energy Storage in the Energy Storage Bunker: During off-peak periods of excess electricity supply, the compressed air energy storage system activates its energy storage function. The airway valve 10 opens, the waterway automatic shutoff valve 4 opens, and the compressor 12 begins operating, continuously compressing air into the energy storage bunker 1. The water in the bunker 1 is gradually pumped into the upper reservoir 16 of the pumped storage power station. When the liquid level sensor in the bunker 1 reaches the designed minimum water level 8, the compressor 12 stops, completing the energy storage process. This process is defined as I1.

[0128] The subsequent steps 3 and 4 are circulated to realize the pure constant pressure operation of the compressed air energy storage system. During the pure constant pressure operation of the compressed air energy storage system, the waterway automatic shut-off valve 4 is always in the open state.

[0129] Compressed air energy storage system variable pressure + constant pressure operation logic:

[0130] 1. The original state of the energy storage bin: the energy storage bin 1 is empty, the air pressure is one atmosphere, and the automatic waterway shut-off valve 4 is in the closed state.

[0131] 2. Initialize energy storage in the energy storage bin: the inflation airway valve 10 is opened, the compressor 12 is started, and compressed air enters the energy storage bin 1. The air pressure in the energy storage bin 1 continues to increase until the air pressure in the energy storage bin 1 reaches the maximum design pressure. The inflation airway valve 10 is closed, and the compressor 12 is turned off.

[0132] 3. First energy release of the energy storage warehouse: During peak power demand periods or when the power grid is short of power, the compressed air energy storage system starts generating electricity:

[0133] The first stage of power generation: the automatic shut-off valve 4 of the water channel is closed, the vent valve 11 is opened, and the compressed air in the energy storage bin 1 flows into the expander 13. The expansion of the gas drives the expander 13 to generate electricity. The expander 13 operates in a throttling mode, and most of the air flow enters the first-stage expander. The expander 13 drives the generator to generate electricity. During the power generation process of the expander 13, the compressed air in the energy storage bin 1 gradually decreases, and the air pressure in the energy storage bin 1 gradually decreases.

[0134] Second stage of power generation: After the pressure in energy storage tank 1 drops to the lower limit of the rated operating pressure of the expander's first cylinder, the air supply mode is adopted. The second-stage regulating valve of the expander opens, and most of the air flow enters the second and third stages of the expander. At this time, the air supply state is reached, completing the variable pressure operation and power generation stage of expander 13. The energy storage tank releases energy for the first time, driving the expander to perform a two-stage power generation process, defined as II1;

[0135] During the third power generation phase, as power generation continues during the second phase, the air pressure within the energy storage tank 1 continues to decrease. When the air pressure measured by the air pressure sensor in the energy storage tank 1 equals the water pressure measured by the water pressure sensor 17, that is, when the gas pressure in the energy storage tank equals the water level differential pressure, the automatic waterway shutoff valve 4 opens, allowing water from the pumped-storage power station's upper reservoir 16 to enter the energy storage tank 1 through the pumped-storage power station's water diversion system 3. This allows the energy storage tank 1 to achieve a water-gas co-containment system. A gas-liquid separator, an air separation unit, and a throttle valve are installed before the inlet of the expander 13. The expander 13 now performs constant-pressure expansion and discharge. When the liquid level measured by the liquid level sensor in the energy storage tank 1 reaches the designed maximum water level 7, the automatic waterway shutoff valve 4 automatically closes, and the venting valve 11 closes, halting discharge. This phase marks the constant-pressure power generation phase for the expander 13. This process is defined as II2.

[0136] 4. Second charging and energy storage in the energy storage warehouse: During the off-peak period when there is excess electricity supply, the compressed air energy storage system starts the charging and energy storage function.

[0137] The first stage of charging: the airway valve 10 is opened and the compressor 12 starts working. When the storage gas pressure in the energy storage bin is greater than or equal to the head pressure difference, the waterway automatic shut-off valve 4 opens and continues to compress air into the energy storage bin 1. The water in the energy storage bin 1 is gradually pressed into the upper reservoir 16 of the pumped storage power station. When the liquid level sensor in the energy storage bin 1 monitors the liquid level reaching the designed minimum water level 8 of the energy storage bin, the compressor 12 stops working and the waterway automatic shut-off valve 4 closes. This process is defined as I1.

[0138] The second stage of charging: After the automatic shut-off valve 4 of the water channel is closed, the compressor 12 continues to work. At this time, the air in the energy storage bin 1 is in the process of increasing pressure. When the air pressure in the energy storage bin 1 reaches the maximum design pressure, the inflation airway valve 10 is closed, the compressor 12 stops working, and the energy storage is completed. This process is defined as I2.

[0139] The subsequent steps 3 and 4 are cyclically executed to realize the variable pressure + constant pressure coupled operation of the compressed air energy storage system. During the operation of the compressed air energy storage system, the waterway automatic shut-off valve 4 is opened or closed according to the instruction.

[0140] The following describes the coupled operation logic of the compressed air energy storage system and the pumped storage system in this system:

[0141] Operation logic of pumped storage power station in the system:

[0142] 1. Charging: During off-peak hours when there is excess electricity supply, the pumped storage power station starts pumping water from the lower pumped storage station reservoir 19 to the higher pumped storage station reservoir 16 to raise the water level and complete energy storage. This process is defined as N1.

[0143] 2. Discharge: During peak electricity demand periods or when the grid is short on power, the pumped-storage power station releases water from the upper reservoir 16 back into the lower reservoir 19. As the water flows downward, turbines or turbine generators convert the water energy into electrical energy, generating electricity. This process is defined as N2.

[0144] The operating logic of the entire system:

[0145] By adjusting the opening and closing of the automatic waterway shutoff valve 4 in the system, various charging and discharging combinations of the compressed air energy storage system and the pumped hydroelectric storage system can be achieved. During actual system operation, different charging and discharging strategies can be adopted based on the actual utilization of wind and solar resources or the power supply of the grid.

[0146] 1. When the waterway automatic shut-off valve 4 is permanently closed, the compressed air energy storage system and the pumped storage system operate independently of each other, and the following charging and discharging combinations can be achieved:

[0147] Charging stage: I2+N1

[0148] Discharge stage: Ⅱ1+N2

[0149] 2. The waterway automatic shut-off valve 4 is automatically opened and closed as needed during system operation, and the following charge and discharge combinations can be achieved:

[0150] Charging stage: I1+I2+N1

[0151] Discharge stage: Ⅱ1+Ⅱ2+N2

[0152] Among them, during the power generation stage of the pumped storage power station, the waterway automatic shut-off valve 4 is opened, and the energy storage bin 1 can realize the function of an air cushion type surge chamber.

[0153] The beneficial effects provided by the present invention are:

[0154] 1) By setting up a water transmission channel to establish hydraulic connection with the upper reservoir of the pumped storage power station, the constant pressure operation of the expansion system can be achieved, the charging and discharging efficiency can be improved, and at the same time, the capacity of the energy storage warehouse can be significantly reduced under the same power condition, which reduces the construction cost.

[0155] 2) By installing an automatic shut-off valve on the water supply channel, the energy storage tank can operate independently, allowing the expander to operate at variable pressure. Combined with the beneficial effect of 1), the expander can operate at variable pressure + constant pressure, maximizing the capacity of the energy storage tank.

[0156] 3) By controlling the automatic shut-off valve on the water channel, the energy storage tank can be used as an air cushion surge well of the pumped storage power station, maximizing the functional utilization of the energy storage tank and reducing the cost of the pumped storage power station.

[0157] The present invention is applicable to current projects integrating compressed air energy storage technology with pumped storage power stations. The above description is intended only to illustrate the technical concepts and features of the present invention, but is not limited to current energy storage bins, water pipelines, automatic waterway shut-off valves, etc. Its purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. This embodiment alone is not intended to limit the scope of the present invention. In other words, any equivalent changes or modifications made to the spirit disclosed by the present invention still fall within the scope of the present invention.

Claims

1. The method for operating a variable-pressure constant-pressure operation system coupled with compressed air energy storage and pumped water storage is characterized in that: It includes a compressed air energy storage system, a pumped water storage system, a water pipeline (2), and an automatic waterway shut-off valve (4); The energy storage bin (1) of the compressed air energy storage system is connected to the lower reservoir (19) of the pumped storage power station of the pumped water energy storage system through the water transmission pipeline (2), and the waterway automatic shut-off valve (4) is installed on the water transmission pipeline (2), so that the energy storage bin (1) of the compressed air energy storage system is hydraulically connected to the upper reservoir (16) of the pumped storage power station through the water diversion system (3) of the pumped storage power station, thereby realizing variable pressure and / or constant pressure operation of the compressed air energy storage system; The energy storage bin (1) of the compressed air energy storage system forms a constant water level difference that meets the requirements with the water level of the upper reservoir (16) of the pumped storage power station of the pumped water energy storage system; The compressed air energy storage system comprises the energy storage bin (1), an air transmission pipeline (9), an inflation airway valve (10), an deflation airway valve (11), a compressor (12) and an expander (13); A flexible water-gas separation layer (6) is provided in the energy storage bin (1), and the flexible water-gas separation layer (6) changes adaptively with the water level in the energy storage bin (1); the energy storage bin (1) has a gas storage side and a water storage side through the flexible water-gas separation layer (6); the gas storage side is connected to one end of the gas transmission pipeline (9); the other end of the gas transmission pipeline (9) is connected in parallel to a first gas transmission branch pipe and a second gas transmission branch pipe, the first gas transmission branch pipe is provided with the compressor (12) and the inflation airway valve (10); the second gas transmission branch pipe is provided with the expander (13) and the deflation airway valve (11); The pumped storage system comprises a pumped storage power station water diversion system (3), a pumped storage power station underground powerhouse (15), an upper reservoir of the pumped storage power station (16), a water pressure sensor (17), a tailwater system of the pumped storage power station (18), and a lower reservoir of the pumped storage power station (19); The pumped storage power station water diversion system (3) is used to achieve connections between the upper reservoir (16) of the pumped storage power station, the lower reservoir (19) of the pumped storage power station, the underground powerhouse (15) of the pumped storage power station, and the tailwater system (18) of the pumped storage power station according to the water flow from top to bottom; the water pressure sensor (17) is installed in the water diversion pipeline between the underground powerhouse (15) of the pumped storage power station and the tailwater system (18) of the pumped storage power station; The operation method comprises the following steps: By controlling the opening and closing of the waterway automatic shutoff valve (4) installed in the water pipeline (2), various charging and discharging combinations of the compressed air energy storage system and the pumped water storage system are realized; The compressed air energy storage system has three operating modes: a compressed air energy storage system variable pressure operating mode, a compressed air energy storage system pure constant pressure operating mode, and a compressed air energy storage system variable pressure coupled constant pressure operating mode. The compressed air energy storage system is in a variable pressure operation mode, and the waterway automatic shut-off valve (4) is always in a closed state, comprising the following steps: Step A1, initial state of the energy storage bin: the energy storage bin (1) is empty, and the gas storage pressure is atmospheric pressure; Step A2, initializing energy storage in the energy storage bin: the air duct valve (10) is opened, the compressor (12) is started, and compressed air enters the energy storage bin (1) until the air pressure in the energy storage bin (1) reaches the maximum design pressure, the air duct valve (10) is closed, and the compressor (12) is turned off; Step A3: First energy release of the energy storage bin: During peak electricity demand periods or when the grid is short of power, the compressed air energy storage system starts generating electricity: The first stage of power generation: the deflation airway valve (11) is opened, and the compressed air in the energy storage bin (1) flows into the expander (13). The gas expansion drives the expander (13) to generate electricity. The expander (13) operates in a throttling mode, and most of the air flow enters the first-stage expander. The expander (13) drives the generator to generate electricity. During the power generation process of the expander (13), the compressed air in the energy storage bin (1) gradually decreases, and the air pressure in the energy storage bin (1) gradually decreases. The second stage of power generation: when the pressure of the energy storage bin (1) drops to the lower limit of the rated operating pressure of the first cylinder of the expander, the air supply mode is adopted, the second stage regulating valve of the expander is opened, and most of the air flow enters the second and third stages of the expander. At this time, it is in the air supply state, and the pressure-changing operation power generation stage of the expander (13) is completed until the pressure in the energy storage bin (1) reaches the design lower limit pressure, the air vent valve (11) is closed, and power generation ends; Step A4: Second energy storage in the energy storage warehouse: During off-peak hours when there is excess electricity supply, the compressed air energy storage system starts charging; The inflation airway valve (10) is opened, the compressor (12) is started, and compressed air enters the energy storage bin (1). At this time, the air in the energy storage bin (1) is in a pressurization process. When the air pressure in the energy storage bin (1) reaches the maximum design pressure, the inflation airway valve (10) is closed, the compressor (12) stops working, and energy storage is completed; Steps A3 and A4 are repeated in a cycle to realize the variable pressure operation of the compressed air energy storage system.

2. The operating method of the compressed air energy storage and pumped water storage coupled variable pressure constant pressure operation system according to claim 1 is characterized in that: Sensors for detecting air pressure, temperature and liquid level are arranged in the energy storage bin (1).

3. The operating method of the compressed air energy storage and pumped water storage coupled variable pressure constant pressure operation system according to claim 1, characterized in that: A heat exchange system (14) is installed between the compressor (12) and the expander (13).

4. The method for operating the compressed air energy storage and pumped water storage coupled variable pressure constant pressure operation system according to claim 1, characterized in that: The pure constant pressure operation mode of the compressed air energy storage system includes the following steps: Step B1, the energy storage bin is in its original state: the energy storage bin (1) is empty and the gas storage pressure is atmospheric pressure; Step B2, initializing energy storage in the energy storage bin: the air duct valve (10) is opened, the compressor (12) is started, compressed air enters the energy storage bin (1), and the air pressure in the energy storage bin (1) continuously increases. When the air pressure in the energy storage bin (1) is the same as the water pressure monitored by the water pressure sensor (17), the air duct valve (10) is closed, and the compressor (12) is turned off. Step B3: First energy release of the energy storage bin: During peak electricity demand periods or when the grid is short of power, the compressed air energy storage system starts generating electricity: The automatic shutoff valve (4) of the waterway is opened, and the water in the upper reservoir (16) of the pumped storage power station enters the energy storage bin (1) through the water diversion system (3) of the pumped storage power station. The venting airway valve (11) is opened, and the compressed air in the energy storage bin (1) flows into the expander (13). The gas expands and drives the expander (13) to generate electricity. Since the head difference is basically constant, the expander (13) performs constant pressure expansion to perform work and discharge; After the water level in the energy storage bin (1) reaches the designed maximum water level (7) of the energy storage bin, the waterway automatic shutoff valve (4) automatically closes, the air vent valve (11) closes, and the energy release is completed, thus achieving the constant pressure operation power generation stage of the expander (13); Step B 4: Second energy storage in the energy storage bin: During off-peak hours when there is excess electricity supply, the compressed air energy storage system activates its energy storage function; The air inflatable airway valve (10) is opened, the waterway automatic shut-off valve (4) is opened, and the compressor (12) starts to work, continuously compressing air into the energy storage bin (1), and the water in the energy storage bin (1) is gradually pressed into the upper reservoir (16) of the pumped storage power station. When the water level in the energy storage bin (1) reaches the designed minimum water level (8) of the energy storage bin, the compressor (12) stops working, and energy storage is completed; Steps B3 and B4 are cycled to achieve pure constant pressure operation of the compressed air energy storage system.

5. The operating method of the compressed air energy storage and pumped water storage coupled variable pressure constant pressure operation system according to claim 1, characterized in that: The compressed air energy storage system voltage-variable coupled constant pressure operation mode comprises the following steps: Step C1, the energy storage bin is in its original state: the energy storage bin (1) is empty and the gas storage pressure is atmospheric pressure; Step C2, initializing energy storage in the energy storage bin: the air duct valve (10) is opened, the compressor (12) is started, and compressed air enters the energy storage bin (1) until the air pressure in the energy storage bin (1) reaches the maximum design pressure, the air duct valve (10) is closed, and the compressor (12) is turned off; Step C3: First energy release of the energy storage bin: During peak electricity demand periods or when the grid is short of power, the compressed air energy storage system starts generating electricity: The first stage of power generation: the deflation airway valve (11) is opened, and the compressed air in the energy storage bin (1) flows into the expander (13). The gas expansion drives the expander (13) to generate electricity. The expander (13) operates in a throttling mode, and most of the air flow enters the first-stage expander. The expander (13) drives the generator to generate electricity. During the power generation process of the expander (13), the compressed air in the energy storage bin (1) gradually decreases, and the air pressure in the energy storage bin (1) gradually decreases. The second stage of power generation: when the pressure of the energy storage bin (1) drops to the lower limit of the rated operating pressure of the first cylinder of the expander, the expander is operated in an air supply mode, the second stage regulating valve of the expander is opened, and most of the air flow enters the second and third stages of the expander. At this time, the expander is in an air supply state, and the pressure-changing operation power generation stage of the expander (13) is completed; In the third stage of power generation, as power generation is carried out in the second stage, the gas pressure in the energy storage bin (1) continuously decreases. When the gas pressure in the energy storage bin (1) is the same as the water pressure monitored by the water pressure sensor (17), the waterway automatic shut-off valve (4) opens, and water from the upper reservoir (16) of the pumped storage power station enters the energy storage bin (1) through the water diversion system (3) of the pumped storage power station. The energy storage bin (1) realizes a water-gas co-containment type, and the expander (13) performs constant pressure expansion to perform work and discharge. When the water level in the energy storage bin (1) reaches the designed maximum water level (7) of the energy storage bin, the waterway automatic shutoff valve (4) automatically closes, the air vent valve (11) closes, and the discharge stops, thus realizing the constant pressure operation power generation stage of the expander (13); Step C4: The energy storage bin is charged and stored for the second time. During off-peak hours when there is excess electricity supply, the compressed air energy storage system starts charging and storing energy; The first stage of charging: the air duct valve (10) is opened, and the compressor (12) starts working. When the storage gas pressure of the energy storage bin is greater than or equal to the water head differential pressure, the waterway automatic shut-off valve (4) is opened, and the air is continuously compressed into the energy storage bin (1). The water in the energy storage bin (1) is gradually pressed into the upper reservoir (16) of the pumped storage power station. When the water level in the energy storage bin (1) reaches the designed minimum water level (8) of the energy storage bin, the compressor (12) stops working, and the waterway automatic shut-off valve (4) is closed. Second stage of charging: After the waterway automatic shut-off valve (4) is closed, the compressor (12) continues to work, and the air in the energy storage bin (1) is in a pressurized process. When the air pressure in the energy storage bin (1) reaches the maximum design pressure, the airway valve (10) is closed, and the compressor (12) stops working, completing energy storage; Step C3 and step C4 are circulated to realize the coupled operation of variable pressure and constant pressure of the compressed air energy storage system.

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