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

Abstract

The invention provides a compressed air energy storage and pumped storage coupled variable-pressure and constant-pressure operation system and method. The compressed air energy storage and pumped storage coupled variable-pressure and constant-pressure operation system comprises a compressed air energy storage system, a pumped storage system, a water conveying pipeline and a water channel automatic cut-off valve. An energy storage bin of the compressed air energy storage system is connected to a pumped storage power station lower reservoir of the pumped storage system through a water conveying pipeline, and a water channel automatic cut-off valve is installed on the water conveying pipeline, so that the energy storage bin of the compressed air energy storage system is in hydraulic connection with a pumped storage power station upper reservoir through a pumped storage power station water diversion system; and variable-pressure and / or constant-pressure operation of the compressed air energy storage system is realized. By means of the method, compressed air energy storage variable pressure and constant pressure two-section operation can be achieved, the energy storage efficiency is improved, meanwhile, the space needed by a compressed air energy storage bin is greatly reduced, and the compressed air energy storage investment cost is greatly reduced. Meanwhile, through adjustment of a pipeline valve, the energy storage bin can achieve the function of an air cushion type surge shaft of the pumped storage power station.

Description

Technical Field

[0001] The present invention relates to the technical field of compressed air energy storage, and particularly to a compressed air energy storage and pumped - storage energy storage coupled variable - pressure and constant - pressure operation system and method. 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, etc. However, due to the influence of the charge - discharge 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 for the gas storage chamber and the existence of cushion gas, and the expansion machine operates in a variable - pressure mode, which to a certain extent reduces the conversion efficiency from electricity to electricity. Summary of the Invention

[0003] Aiming at the defects existing in the prior art, the present invention provides a compressed air energy storage and pumped - storage energy storage coupled variable - pressure and constant - pressure operation system and method, which can effectively solve the above problems.

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

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

[0006] The energy storage chamber (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 energy storage system through the water conveyance pipeline (2), and the water channel automatic cut - off valve (4) is installed on the water conveyance pipeline (2), so that the energy storage chamber (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 intake system (3) of the pumped - storage power station, realizing variable - pressure and / or constant - pressure operation of the compressed air energy storage system.

[0007] Preferably, the energy storage chamber (1) of the compressed air energy storage system forms a constant and required water level difference with the water level of the upper reservoir (16) of the pumped - storage power station of the pumped - storage energy storage system.

[0008] Preferably, the compressed air energy storage system includes the energy storage chamber (1), a gas transmission pipeline (9), an air - charging airway valve (10), an air - discharging airway valve (11), a compressor (12), and an expander (13);

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

[0010] Preferably, sensors for detecting air pressure, temperature and liquid level are arranged inside 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 system includes a pumped-storage power station water intake 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 tailrace system (18) and a pumped-storage power station lower reservoir (19);

[0013] Through the pumped-storage power station water intake system (3), in the direction of water flow from top to bottom, 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 tailrace system (18) is realized; a water pressure sensor (17) is installed on the water delivery pipeline between the pumped-storage power station underground powerhouse (15) and the pumped-storage power station tailrace system (18).

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

[0015] By controlling the opening and closing of the water channel automatic cut-off valve (4) installed on the water delivery pipeline (2), various charge-discharge combination forms of the compressed air energy storage system and the pumped-storage system are realized;

[0016] Among them, for the compressed air energy storage system, there are three operation modes, namely: the variable-pressure operation mode of the compressed air energy storage system, the pure constant-pressure operation mode of the compressed air energy storage system, and the variable-pressure coupled constant-pressure operation mode of the compressed air energy storage system.

[0017] Preferably, in the variable-pressure operation mode of the compressed air energy storage system, the water channel automatic cut-off valve (4) is always in the closed state, including the following steps:

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

[0019] Step A2, Initial energy storage of the energy storage chamber: The inflation airway valve (10) is opened, the compressor (12) is started, compressed air enters the energy storage chamber (1) until the air pressure in the energy storage chamber (1) reaches the maximum design pressure, the inflation airway valve (10) is closed, and the compressor (12) is turned off;

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

[0021] During peak power demand periods or when the power grid power supply is insufficient, the compressed air energy storage system starts to generate electricity:

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

[0023] Second stage of power generation: When the pressure in the energy storage chamber (1) drops to the lower limit of the rated operating pressure of the first cylinder of the expander, a supplementary 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 a supplementary air supply state, completing the variable-pressure operation power generation stage of the expander (13) until the pressure in the energy storage chamber (1) reaches the design lower limit pressure, the deflation airway valve (11) is closed, and the power generation ends;

[0024] Step A4, Second energy storage of the energy storage chamber:

[0025] During the low peak period of power supply surplus, the compressed air energy storage system starts the charging function;

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

[0027] Steps A3 and A4 are cycled to achieve the variable-pressure operation of the compressed air energy storage system.

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

[0029] Step B1, initial state of the energy storage chamber: The energy storage chamber (1) is empty and the gas storage pressure is atmospheric pressure;

[0030] Step B2, initial energy storage of the energy storage chamber: The inflation air duct valve (10) is opened, the compressor (12) is started, compressed air enters the energy storage chamber (1), the air pressure in the energy storage chamber (1) continuously increases, and when the gas storage pressure in the energy storage chamber (1) is the same as the water pressure monitored by the water pressure sensor (17), the inflation air duct valve (10) is closed and the compressor (12) is shut down;

[0031] Step B3, first energy release of the energy storage chamber:

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

[0033] The water channel automatic cut-off valve (4) is opened, the water in the upper reservoir (16) of the pumped storage power station enters the energy storage chamber (1) through the water diversion system (3) of the pumped storage power station, the air release air duct valve (11) is opened, and the compressed air in the energy storage chamber (1) flows into the expander (13). The gas expansion pushes the expander (13) to generate electricity. Since the water head difference is basically constant, the expander (13) performs constant-pressure expansion work to discharge electricity;

[0034] After the water level in the energy storage chamber (1) reaches the designed maximum water level (7) of the energy storage chamber, the water channel automatic cut-off valve (4) automatically closes, the air release air duct valve (11) is closed, and the energy release is completed, realizing the constant-pressure operation power generation stage of the expander (13);

[0035] Step B4, second energy storage of the energy storage chamber:

[0036] During low peak periods of oversupply of electric power, the compressed air energy storage system starts the energy storage function;

[0037] The inflation air duct valve (10) is opened, the water channel automatic cut-off valve (4) is opened, the compressor (12) starts to work, continuously compressing air into the energy storage chamber (1). The water in the energy storage chamber (1) is gradually pressed into the upper reservoir (16) of the pumped storage power station. When the water level in the energy storage chamber (1) reaches the designed minimum water level (8) of the energy storage chamber, the compressor (12) stops working and the 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 variable-pressure coupling constant-pressure operation mode of the compressed air energy storage system includes the following steps:

[0040] Step C1, initial state of the energy storage chamber: The energy storage chamber (1) is empty and the gas storage pressure is atmospheric pressure;;

[0041] Step C2. Initial energy storage in the energy storage chamber: The inflatable airway valve (10) is opened, the compressor (12) is started, compressed air enters the energy storage chamber (1) until the air pressure in the energy storage chamber (1) reaches the maximum design pressure, the inflatable airway valve (10) is closed, and the compressor (12) is closed;

[0042] Step C3. First energy release from the energy storage chamber:

[0043] During peak power demand periods or when the power grid power supply is insufficient, the compressed air energy storage system starts to generate electricity:

[0044] First stage of power generation: The air release airway valve (11) is opened, the compressed air in the energy storage chamber (1) flows into the expander (13), the gas expands to drive the expander (13) to generate electricity, the expander (13) operates in a throttling mode, most of the air flow enters the first-stage expander, and the expander (13) drives the generator to do work and generate electricity; during the power generation process of the expander (13), the compressed air in the energy storage chamber (1) gradually decreases, and the air pressure in the energy storage chamber (1) gradually decreases;

[0045] Second stage of power generation: When the pressure in the energy storage chamber (1) drops to the lower limit of the rated operating pressure of the first cylinder of the expander, a gas replenishment 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 a gas replenishment state, completing the variable-pressure operation power generation stage of the expander (13);

[0046] Third stage of power generation: With the power generation in the second stage, the air pressure in the energy storage chamber (1) continues to decrease. When the air storage pressure in the energy storage chamber (1) is the same as the water pressure monitored by the water pressure sensor (17), the waterway automatic cut-off valve (4) is opened, and the water in the upper reservoir (16) of the pumped-storage power station enters the energy storage chamber (1) through the water diversion system (3) of the pumped-storage power station. The energy storage chamber (1) realizes the water-air coexistence mode in the energy storage chamber, and the expander (13) performs constant-pressure expansion work to discharge electricity;

[0047] When the water level in the energy storage chamber (1) reaches the highest design water level (7) of the energy storage chamber, the waterway automatic cut-off valve (4) automatically closes, the air release airway valve (11) closes, and the power discharge stops, realizing the constant-pressure operation power generation stage of the expander (13);

[0048] Step C4. Second charging and energy storage in the energy storage chamber:

[0049] During the low peak period of oversupply of power supply, the compressed air energy storage system starts the charging and energy storage function.

[0050] The first charging stage: The air inlet valve of the air charging channel (10) is opened, and the compressor (12) starts to work. When the air storage pressure in the energy storage warehouse ≥ the head difference pressure, the automatic cut-off valve of the water channel (4) is opened, and the compressed air is continuously compressed into the energy storage warehouse (1). The water in the energy storage warehouse (1) is gradually pressed into the upper reservoir (16) of the pumped-storage power station. When the water level in the energy storage warehouse (1) reaches the lowest designed water level (8) of the energy storage warehouse, the compressor (12) pauses working, and the automatic cut-off valve of the water channel (4) is closed;

[0051] The second charging stage: After the automatic cut-off valve of the water channel (4) is closed, the compressor (12) continues to work. At this time, the air in the energy storage warehouse (1) is in the process of pressure increase. When the air pressure in the energy storage warehouse (1) reaches the maximum designed pressure, the air inlet valve of the air charging channel (10) is closed, and the compressor (12) stops working, completing the energy storage;

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

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

[0054] 1) By setting a hydraulic connection between the water conveyance channel and the upper reservoir of the pumped-storage power station, the constant pressure operation of the expansion system can be realized, improving the charge and discharge efficiency. At the same time, under the same power, the capacity of the energy storage warehouse is significantly reduced, and the cost is reduced.

[0055] 2) By setting an automatic cut-off valve of the water channel on the water conveyance channel, the energy storage warehouse can operate independently, enabling the expander to operate under variable pressure. Combining the beneficial effects of 1), the variable pressure + constant pressure operation of the expander is realized, maximizing the utilization of the capacity of the energy storage warehouse.

[0056] 3) By controlling the automatic cut-off valve of the water channel on the water conveyance channel, the energy storage warehouse can be used as a pneumatic surge chamber of the pumped-storage power station, maximizing the utilization of the function of the energy storage warehouse and reducing the cost of the pumped-storage power station. Description of the Drawings

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

[0058] Wherein: 1 - energy storage chamber; 2 - water conveyance pipeline; 3 - water intake system of the pumped - storage power station; 4 - automatic waterway cut - off valve; 5 - air pressure / temperature / liquid level sensor; 6 - flexible water - gas separation layer; 7 - designed highest water level of the energy storage chamber; 8 - designed lowest water level of the energy storage chamber; 9 - gas conveyance pipeline; 10 - air - charging airway valve; 11 - air - discharging airway valve; 12 - compressor; 13 - expander; 14 - heat exchange system; 15 - underground power house of the pumped - storage power station; 16 - upper reservoir of the pumped - storage power station; 17 - water pressure sensor; 18 - tail - water system of the pumped - storage power station; 19 - lower reservoir of the pumped - storage power station. Detailed implementation manners

[0059] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clear and understandable, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0060] Based on the existing compressed - air energy - storage technology, the present invention proposes an operation method that utilizes the high - head water level difference of a pumped - storage power station to drive the remaining gas in the gas storage reservoir to do work, which can effectively realize the variable - pressure + constant - pressure operation of the compressed - air energy - storage expansion system. While improving the efficiency, it can greatly reduce the scale of the underground energy - storage chamber. At the same time, by using the principle of automatic control of the waterway valve, the function of the air - cushioned surge chamber of the energy - storage chamber is realized. The present invention has practical significance both in reducing the scale of the gas storage reservoir and the construction cost of the gas storage reservoir from the perspective of compressed - air energy - storage technology, and in improving the conversion efficiency of the compressed - air energy - storage power station.

[0061] Refer to Figure 1 , the present invention provides a compressed - air energy - storage and pumped - storage energy - storage coupled variable - pressure and constant - pressure operation system, relying on an actual project, including a compressed - air energy - storage system, a pumped - storage energy - storage system, a water conveyance pipeline 2, and an automatic waterway cut - off valve 4;

[0062] The energy - storage chamber 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 energy - storage system through the water conveyance pipeline 2. The automatic waterway cut - off valve 4 is installed on the water conveyance pipeline 2, so that the energy - storage chamber 1 of the compressed - air energy - storage system has a hydraulic connection with the upper reservoir 16 of the pumped - storage power station through the water intake system 3 of the pumped - storage power station. By controlling the closing and opening of the automatic waterway cut - off valve 4, the variable - pressure and / or constant - pressure operation of the compressed - air energy - storage system is realized. The variable - pressure and constant - pressure here refer to the pressure change in the energy - storage chamber 1.

[0063] In the present invention, the water conveyance pipeline 2 is connected to the water intake system 3 of the pumped storage power station at the bottom. The energy storage tank 1 can utilize the net head pressure of the upper reservoir; the energy storage tank 1 can also have a hydraulic connection with the upper reservoir directly through the water conveyance pipeline 2. For example, the energy storage tank 1 of the compressed air energy storage system is located at the bottom of the whole system, has a hydraulic connection with the upper reservoir 16 of the pumped storage power station through the water intake system 3 of the pumped storage power station, and forms a constant and required water level difference with the water level of the upper reservoir 16 of the pumped storage power station of the pumped storage system.

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

[0065] A flexible water-gas separation layer 6 is arranged inside the energy storage tank 1, and the flexible water-gas separation layer 6 changes adaptively with the water level inside the energy storage tank 1; through the flexible water-gas separation layer 6, the energy storage tank 1 has a gas storage side and a water storage side; by arranging the flexible water-gas separation layer 6 on the inner wall of the energy storage tank 1, the air and water in the energy storage tank 1 are completely isolated during the air charging / discharging / water discharging process, avoiding excessive humidity of the air.

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

[0067] As a specific implementation manner, the pumped storage system includes the water intake system 3 of the pumped storage power station, the underground power house 15 of the pumped storage power station, the upper reservoir 16 of the pumped storage power station, the water pressure sensor 17, the tail water system 18 of the pumped storage power station and the lower reservoir 19 of the pumped storage power station;

[0068] Through the water intake system 3 of the pumped storage power station, in the direction from top to bottom of the water flow, 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 power house 15 of the pumped storage power station and the tail water system 18 of the pumped storage power station is realized; a water pressure sensor 17 is installed on the water conveyance pipeline between the underground power house 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 in a linkage relationship with the compressor 12, the expander 13, and the water channel automatic cut-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 water channel automatic cut-off valve 4 automatically close or open according to the instructions.

[0070] By adjusting the opening and closing of the water channel automatic cut-off valve 4 in the system, various charge-discharge combination forms of compressed air energy storage and pumped-storage energy storage can be realized. The water channel automatic cut-off valve 4 specifically regulates the opening and closing of the valve according to the liquid level change and air pressure change in the energy storage bin 1.

[0071] A compressed air energy storage and pumped-storage energy storage coupled variable pressure + constant pressure operation system and method disclosed by the present invention is a deep coupling variable pressure + constant pressure staged operation system and method for a compressed air energy storage power station and a pumped-storage energy storage power station. By setting a water conveyance pipeline, the energy storage bin in the compressed air energy storage system has a hydraulic connection with the upper reservoir of the pumped-storage power station through the pumped-storage water diversion system. A water channel automatic cut-off valve is arranged between the water conveyance pipeline and the energy storage bin, and a flexible water-gas separation layer is arranged in the energy storage bin to achieve water-gas coexistence and separation. This method can realize two-stage operation of variable pressure + constant pressure of compressed air energy storage, improve the energy storage efficiency, greatly reduce the required space of 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 coexistence bin) can realize the function of the air cushion surge chamber of the pumped-storage power station.

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

[0073] By controlling the opening and closing of the water channel automatic cut-off valve 4 installed on the water conveyance pipeline 2, various charge-discharge combination forms of the compressed air energy storage system and the pumped-storage energy storage system are realized;

[0074] Among them, for the compressed air energy storage system, there are three operation modes, namely: the variable pressure operation mode of the compressed air energy storage system, the pure constant pressure operation mode of the compressed air energy storage system, and the variable pressure coupled constant pressure operation mode of the compressed air energy storage system.

[0075] In the variable pressure operation mode of the compressed air energy storage system, the water channel automatic cut-off valve 4 is always in the closed state, including the following steps:

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

[0077] Step A2. Initial energy storage in the energy storage chamber: The inflation air duct valve 10 is opened, the compressor 12 is started, and compressed air enters the energy storage chamber 1 until the air pressure in the energy storage chamber 1 reaches the maximum design pressure. Then the inflation air duct valve 10 is closed and the compressor 12 is turned off.

[0078] Step A3. First energy release from the energy storage chamber:

[0079] During peak power demand periods or when the power grid power supply is insufficient, the compressed air energy storage system starts to generate electricity:

[0080] First stage of power generation: The deflation air duct valve 11 is opened, and the compressed air in the energy storage chamber 1 flows into the expander 13. The gas expands to drive 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 do work and generate electricity. During the power generation process of the expander 13, the compressed air in the energy storage chamber 1 gradually decreases, and the air pressure in the energy storage chamber 1 gradually decreases.

[0081] Second stage of power generation: When the pressure in the energy storage chamber 1 drops to the lower limit of the rated operating pressure of the first cylinder of the expander, a supplementary air intake mode is adopted, and the second-stage regulating valve of the expander is opened. Most of the air flow enters the second and third stages of the expander. At this time, it is in a supplementary air intake state, completing the variable-pressure operation power generation stage of the expander 13 until the pressure in the energy storage chamber 1 reaches the designed lower limit pressure, and the deflation air duct valve 11 is closed, and the power generation ends.

[0082] Step A4. Second energy storage in the energy storage chamber:

[0083] During the low peak period when the power supply is in excess, the compressed air energy storage system starts the charging function;

[0084] The inflation air duct valve 10 is opened, the compressor 12 starts to work, and compressed air enters the energy storage chamber 1. At this time, the air in the energy storage chamber 1 is in a pressure-boosting process. When the air pressure in the energy storage chamber 1 reaches the maximum design pressure, the inflation air duct valve 10 is closed, and the compressor 12 stops working, completing the energy storage.

[0085] Steps A3 and A4 are cycled to achieve 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. Original state of the energy storage chamber: The energy storage chamber 1 is empty, and the gas storage pressure is atmospheric pressure.

[0088] Step B2. Initial energy storage in the energy storage chamber: The inflation air duct valve 10 is opened, the compressor 12 is started, compressed air enters the energy storage chamber 1, the air pressure in the energy storage chamber 1 continuously rises. When the air storage pressure in the energy storage chamber 1 is the same as the water pressure monitored by the water pressure sensor 17, the inflation air duct valve 10 is closed and the compressor 12 is closed;

[0089] Step B3. First energy release from the energy storage chamber:

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

[0091] The water channel automatic cut-off valve 4 is opened, the water in the upper reservoir 16 of the pumped storage power station enters the energy storage chamber 1 through the water diversion system 3 of the pumped storage power station, the air release air duct valve 11 is opened, the compressed air in the energy storage chamber 1 flows into the expander 13, and the gas expansion pushes the expander 13 to generate electricity. Since the water head difference is basically constant, the expander 13 performs constant-pressure expansion work to discharge electricity;

[0092] When the water level in the energy storage chamber 1 reaches the designed maximum water level 7 of the energy storage chamber, the water channel automatic cut-off valve 4 automatically closes, the air release air duct valve 11 is closed, the energy release is completed, and the constant-pressure operation power generation stage of the expander 13 is realized;

[0093] Step B4. Second energy storage in the energy storage chamber:

[0094] During the low peak period when the power supply is in excess, the compressed air energy storage system starts the energy storage function;

[0095] The inflation air duct valve 10 is opened, the water channel automatic cut-off valve 4 is opened, the compressor 12 starts to work, continuously compresses air into the energy storage chamber 1, the water in the energy storage chamber 1 is gradually pressed into the upper reservoir 16 of the pumped storage power station. When the water level in the energy storage chamber 1 reaches the designed minimum water level 8 of the energy storage chamber, the compressor 12 stops working and the energy storage is completed;

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

[0097] The variable-pressure coupling constant-pressure operation mode of the compressed air energy storage system includes the following steps:

[0098] Step C1. Original state of the energy storage chamber: The energy storage chamber 1 is empty and the air storage pressure is atmospheric pressure;;

[0099] Step C2. Initial energy storage in the energy storage chamber: The inflation air duct valve 10 is opened, the compressor 12 is started, compressed air enters the energy storage chamber 1 until the air pressure in the energy storage chamber 1 reaches the maximum designed pressure, the inflation air duct valve 10 is closed, and the compressor 12 is closed;

[0100] Step C3. First energy release from the energy storage chamber:

[0101] During peak power demand periods or when the power grid's power supply is insufficient, the compressed air energy storage system starts generating electricity:

[0102] First stage of power generation: The exhaust airway valve 11 opens, and the compressed air in the energy storage chamber 1 flows into the expander 13. The gas expands to drive 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 do work and generate electricity; during the process of the expander 13 generating electricity, the compressed air in the energy storage chamber 1 gradually decreases, and the air pressure in the energy storage chamber 1 gradually decreases;

[0103] Second stage of power generation: When the pressure in the energy storage chamber 1 drops to the lower limit of the rated operating pressure of the first cylinder of the expander, it operates in a supplementary air 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. At this time, it is in a supplementary air state, completing the variable-pressure operation power generation stage of the expander 13;

[0104] Third stage of power generation: With the power generation in the second stage, the air pressure in the energy storage chamber 1 continuously decreases. When the air storage pressure in the energy storage chamber 1 is the same as the water pressure monitored by the water pressure sensor 17, the water channel automatic cut-off valve 4 opens. The water in the upper reservoir 16 of the pumped-storage power station enters the energy storage chamber 1 through the water diversion system 3 of the pumped-storage power station. The energy storage chamber 1 realizes the coexistence of water and air in the energy storage chamber, and the expander 13 performs constant-pressure expansion work and discharges electricity;

[0105] When the water level in the energy storage chamber 1 reaches the design maximum water level 7 of the energy storage chamber, the water channel automatic cut-off valve 4 automatically closes, and the exhaust airway valve 11 closes, stopping the power discharge, and realizing the constant-pressure operation power generation stage of the expander 13;

[0106] Step C4: Second charging and energy storage of the energy storage chamber:

[0107] During the low-demand period when the power supply is in excess, the compressed air energy storage system starts the charging and energy storage function.

[0108] First stage of charging: The inflation airway valve 10 opens, and the compressor 12 starts to work. When the air storage pressure in the energy storage chamber ≥ the head difference pressure, the water channel automatic cut-off valve 4 opens, continuously compressing air into the energy storage chamber 1. The water in the energy storage chamber 1 is gradually pressed into the upper reservoir 16 of the pumped-storage power station. When the water level in the energy storage chamber 1 reaches the design minimum water level 8 of the energy storage chamber, the compressor 12 pauses working, and the water channel automatic cut-off valve 4 closes;

[0109] Second stage of charging: After the water channel automatic cut-off valve 4 closes, the compressor 12 continues to work. At this time, the air in the energy storage chamber 1 is in a pressure-boosting process. When the air pressure in the energy storage chamber 1 reaches the maximum design pressure, the inflation airway valve 10 closes, and the compressor 12 stops working, completing the energy storage;

[0110] Steps C3 and C4 are cycled to achieve the coupled operation of variable pressure and constant pressure of the compressed air energy storage system.

[0111] The following introduces an embodiment:

[0112] The compressed air energy storage bin 1 is hydraulically connected to the upper reservoir 16 of the pumped-storage power station through the water conveyance pipeline 2 to achieve the variable pressure + constant pressure operation of compressed air energy storage. By setting the automatic water channel cutoff valve 4 on the water conveyance pipeline 2, the function of the system is realized; by controlling the automatic water channel cutoff valve 4, the coupled operation of two energy storage methods of compressed air energy storage and pumped-storage in the system is realized.

[0113] This compressed air energy storage system can achieve three operation schemes, namely variable pressure operation, pure constant pressure operation, and variable pressure + constant pressure coupled operation. The operation logics of the three operation schemes are described below respectively:

[0114] Variable pressure operation logic of the compressed air energy storage system:

[0115] 1. Initial state of the energy storage bin: The energy storage bin 1 is empty, the air pressure is one atmospheric pressure, and the automatic water channel cutoff valve 4 is in the closed state.

[0116] 2. Initial energy storage of the energy storage bin: The inflation 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 until the air pressure in the energy storage bin 1 reaches the maximum design pressure, then the inflation air duct valve 10 is closed and the compressor 12 is turned off.

[0117] 3. First energy release of the energy storage bin: During the peak period of power demand or when the power supply of the power grid is insufficient, the compressed air energy storage system starts to generate electricity:

[0118] First stage of power generation: The automatic water channel cutoff valve 4 is in the closed state, the air release duct valve 11 is opened, the compressed air in the energy storage bin 1 flows into the expander 13, the gas expands to drive the expander 13 to generate electricity, the expander 13 operates in a throttling mode, most of the air flow enters the first-stage expander, and the expander 13 drives the generator to do work and 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] Second stage of power generation: When the pressure in the energy storage bin 1 drops to the lower limit of the rated operating pressure of the first cylinder of the expander, the air replenishment 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 replenishment state, and the variable pressure 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, then the air release duct valve 11 is closed and the power generation ends. This process is defined as II1.

[0120] 4. Second energy storage of the energy storage chamber: During the low peak period of over - supplied power, the compressed air energy storage system activates the charging function. The water channel automatic cut - off valve 4 remains closed all the time. The air charging channel valve 10 is opened, and the compressor 12 starts to work. Compressed air enters the energy storage chamber 1. At this time, the air in the energy storage chamber 1 is in the process of pressure increase. When the air pressure in the energy storage chamber 1 reaches the maximum design pressure, the air charging channel valve 10 is closed, and the compressor 12 stops working, completing the energy storage. This process is defined as I2.

[0121] Subsequently, steps 3 and 4 are cycled 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 water channel automatic cut - off valve 4 needs to remain closed all the time.

[0122] Pure constant - pressure operation logic of the compressed air energy storage system:

[0123] 1. Original state of the energy storage chamber 1: The energy storage chamber 1 is empty, the air pressure is one atmosphere, and the water channel automatic cut - off valve 4 is in the closed state.

[0124] 2. Initial energy storage of the energy storage chamber: The air charging channel valve 10 is opened, the compressor 12 is started, and compressed air enters the energy storage chamber 1. The air pressure in the energy storage chamber 1 continuously increases. When the air pressure monitored by the air pressure sensor in the energy storage chamber 1 = the water pressure monitored by the water pressure sensor 17, the air charging channel valve 10 is closed, and the compressor 12 is closed, completing the initial energy storage.

[0125] 3. First energy release of the energy storage chamber: During the peak power demand period or when the power grid power supply is insufficient, the compressed air energy storage system starts to generate electricity:

[0126] The water channel automatic cut - off valve 4 is opened, the water in the upper reservoir 16 of the pumped - storage power station enters the energy storage chamber 1 through the water diversion system 3 of the pumped - storage power station. The air release channel valve 11 is opened, and the compressed air in the energy storage chamber 1 flows into the expander 13. The gas expands to drive the expander 13 to generate electricity. Since the head difference is basically constant, the expander 13 performs constant - pressure expansion work to discharge electricity at this time. When the liquid level sensor in the energy storage chamber 1 monitors that the liquid level reaches the designed highest water level 7 of the energy storage chamber, the water channel automatic cut - off valve 4 automatically closes, and the air release channel valve 11 is closed, and the energy release is completed. This process realizes the constant - pressure operation power generation stage of the expander 13. This process is defined as Ⅱ2.

[0127] 4. Second energy storage of the energy storage chamber: During the low peak period of over - supplied power, the compressed air energy storage system activates the energy storage function. The air charging channel valve 10 is opened, the water channel automatic cut - off valve 4 is opened, and the compressor 12 starts to work, continuously compressing air into the energy storage chamber 1. The water in the energy storage chamber 1 is gradually pressed into the upper reservoir 16 of the pumped - storage power station. When the liquid level sensor in the energy storage chamber 1 monitors that the liquid level reaches the designed lowest water level 8 of the energy storage chamber, the compressor 12 stops working, completing the energy storage. This process is defined as I1.

[0128] Subsequently, the 3rd and 4th steps are cycled to achieve 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 cut-off valve 4 is always in the open state.

[0129] Variable pressure + constant pressure operation logic of the compressed air energy storage system:

[0130] 1. Original state of the energy storage chamber: The energy storage chamber 1 is empty, the air pressure is one atmospheric pressure, and the waterway automatic cut-off valve 4 is in the closed state.

[0131] 2. Initial energy storage of the energy storage chamber: The inflation air duct valve 10 is opened, the compressor 12 is started, compressed air enters the energy storage chamber 1, and the air pressure in the energy storage chamber 1 continuously increases until the air pressure in the energy storage chamber 1 reaches the maximum design pressure, then the inflation air duct valve 10 is closed and the compressor 12 is shut down.

[0132] 3. First energy release of the energy storage chamber: During peak power demand periods or when the grid power supply is insufficient, the compressed air energy storage system starts to generate electricity:

[0133] First stage of power generation: The waterway automatic cut-off valve 4 is in the closed state, the air release duct valve 11 is opened, and the compressed air in the energy storage chamber 1 flows into the expander 13. The gas expands to drive 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 do work and generate electricity; during the power generation process of the expander 13, the compressed air in the energy storage chamber 1 gradually decreases, and the air pressure in the energy storage chamber 1 gradually decreases;

[0134] Second stage of power generation: When the pressure in the energy storage chamber 1 drops to the lower limit of the rated operating pressure of the first cylinder of the expander, a supplementary air intake mode is adopted, and the second-stage regulating valve of the expander is opened. Most of the air flow enters the second and third stages of the expander. At this time, it is in the supplementary air intake state, completing the variable pressure operation power generation stage of the expander 13. The first energy release of the energy storage chamber, driving the expander to perform a two-stage power generation process, is defined as Ⅱ1;

[0135] Third stage of power generation: With the power generation in the second stage, the air pressure in the energy storage chamber 1 continuously decreases. When the air pressure sensor in the energy storage chamber 1 monitors the air pressure = the water pressure sensor 17 monitors the water pressure, that is, when the energy storage pressure in the energy storage chamber = the water level difference pressure, the waterway automatic cut-off valve 4 is opened, and the water in the upper reservoir 16 of the pumped storage power station enters the energy storage chamber 1 through the water diversion system 3 of the pumped storage power station. The energy storage chamber 1 realizes the gas-liquid coexistence type in the energy storage chamber. A gas-liquid separator, an air separation device, and a throttle valve are configured in front of the inlet of the expander 13. At this time, the expander 13 performs constant-pressure expansion work and discharges electricity. When the liquid level sensor in the energy storage chamber 1 monitors that the liquid level reaches the highest designed water level 7 of the energy storage chamber, the waterway automatic cut-off valve 4 automatically closes, the air release duct valve 11 closes, and the power discharge stops. This stage realizes the constant-pressure operation power generation stage of the expander 13. This process is defined as Ⅱ2.

[0136] 4. Second charging and energy storage of the energy storage tank: During the low peak period of over-abundant power supply, the compressed air energy storage system starts its charging and energy storage function.

[0137] First stage of charging: The inflation airway valve 10 opens, and the compressor 12 starts to work. When the air storage pressure in the energy storage tank ≥ the head difference pressure, the waterway automatic cut-off valve 4 opens, and the air is continuously compressed into the energy storage tank 1. The water in the energy storage tank 1 is gradually pressed into the upper reservoir 16 of the pumped-storage power station. When the liquid level sensor in the energy storage tank 1 monitors that the liquid level reaches the designed lowest water level 8 of the energy storage tank, the compressor 12 pauses working, and the waterway automatic cut-off valve 4 closes. This process is defined as I1.

[0138] Second stage of charging: After the waterway automatic cut-off valve 4 closes, the compressor 12 continues to work. At this time, the air in the energy storage tank 1 is in the process of pressure increase. When the air pressure in the energy storage tank 1 reaches the maximum designed pressure, the inflation airway valve 10 closes, and the compressor 12 stops working, completing the energy storage. This process is defined as I2.

[0139] Subsequent steps 3 and 4 are cycled to achieve the coupled operation of variable pressure + constant pressure of the compressed air energy storage system. During the operation of the compressed air energy storage system, the waterway automatic cut-off valve 4 opens or closes according to the instruction.

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

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

[0142] 1. Charging: During the low peak period of over-abundant power supply, the pumped-storage power station pumps water from the lower reservoir 19 of the pumped-storage power station to the higher upper reservoir 16 of the pumped-storage power station by starting the water pump to raise the water level and complete the energy storage. This process is defined as N1.

[0143] 2. Discharging: During the peak period of power demand or when the power supply of the power grid is insufficient, the pumped-storage power station releases the water from the upper reservoir 16 of the pumped-storage power station back to the lower reservoir 19 of the pumped-storage power station. During the process of the water flowing down, the water energy is converted into electric energy through the water turbine or the turbine generator set to complete the power generation. This process is defined as N2.

[0144] Operation logic of the whole system:

[0145] By adjusting the opening and closing of the waterway automatic cut-off valve 4 in the system, various charge and discharge combination forms of the compressed air energy storage system and the pumped-storage system can be realized. During the actual operation of the system, different charge and discharge strategies can be adopted according to the actual utilization situation of wind and light resources or the power supply situation of the power grid.

[0146] 1. When the waterway automatic cut-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 charge-discharge combinations can be achieved:

[0147] Charging stage: I2 + N1

[0148] Discharging stage: Ⅱ1 + N2

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

[0150] Charging stage: I1 + I2 + N1

[0151] Discharging stage: Ⅱ1 + Ⅱ2 + N2

[0152] Among them, during the power generation stage of the pumped storage power station, when the waterway automatic cut-off valve 4 is opened, the energy storage bin 1 can achieve the function of a pneumatic surge chamber.

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

[0154] 1) By setting up a hydraulic connection between the water conveyance channel and the upper reservoir of the pumped storage power station, the constant pressure operation of the expansion system can be achieved, improving the charge-discharge efficiency. At the same time, under the same power, the capacity of the energy storage bin is significantly reduced, and the cost is reduced.

[0155] 2) By setting a waterway automatic cut-off valve on the water conveyance channel, the energy storage bin can operate independently, enabling the expander to operate under variable pressure. Combining with the beneficial effect of 1), the variable pressure + constant pressure operation of the expander is achieved, maximizing the utilization of the capacity of the energy storage bin.

[0156] 3) By controlling the waterway automatic cut-off valve on the water conveyance channel, the energy storage bin can be used as a pneumatic surge shaft of the pumped storage power station, maximizing the utilization of the energy storage bin function and reducing the cost of the pumped storage power station.

[0157] The present invention is applicable to the current project of deep co-construction of compressed air energy storage technology and pumped storage power stations. The above description is only used to illustrate the technical idea and characteristics of the present invention, but is not limited to the current energy storage bin, water conveyance pipeline, waterway automatic cut-off valve, etc. Its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The patent scope of the present invention cannot be limited only by this embodiment, that is, any equivalent changes or modifications made according to the spirit disclosed by the present invention still fall within the patent scope of the present invention.

Claims

1. Compressed air energy storage and pumped hydro energy storage coupled variable pressure and constant pressure operation system, characterized in that, It includes a compressed air energy storage system, a pumped-storage energy storage system, a water conveyance pipeline (2), and a water channel automatic cut-off valve (4); The energy storage tank (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 energy storage system through the water conveyance pipeline (2). The water channel automatic cut-off valve (4) is installed on the water conveyance pipeline (2), so that the energy storage tank (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 intake system (3) of the pumped-storage power station, realizing variable-pressure and / or constant-pressure operation of the compressed air energy storage system.

2. The compressed air energy storage and pumped storage coupled variable pressure constant pressure operation system according to claim 1, characterized in that, The energy storage tank (1) of the compressed air energy storage system forms a constant and required water level difference with the water level of the upper reservoir (16) of the pumped-storage energy storage system.

3. The compressed air energy storage and pumped storage coupled variable pressure and constant pressure operation system according to claim 1, characterized in that, The compressed air energy storage system includes the energy storage tank (1), a gas transmission pipeline (9), an air charging airway valve (10), an air discharging airway valve (11), a compressor (12), and an expander (13); A flexible water-gas separation layer (6) is arranged inside the energy storage tank (1). The flexible water-gas separation layer (6) changes adaptively with the water level inside the energy storage tank (1). Through the flexible water-gas separation layer (6), the energy storage tank (1) has a gas storage side and a water storage side. The gas storage side is communicated with 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 air charging airway valve (10). The second gas transmission branch pipe is provided with the expander (13) and the air discharging airway valve (11).

4. The compressed air energy storage and pumped storage coupled variable pressure and constant pressure operation system according to claim 3, wherein Sensors for detecting air pressure, temperature, and liquid level are arranged inside the energy storage tank (1).

5. The compressed air energy storage and pumped-storage coupled variable-pressure constant-pressure operation system according to claim 3, wherein A heat exchange system (14) is installed between the compressor (12) and the expander (13).

6. The compressed air energy storage and pumped storage coupled variable pressure constant pressure operation system according to claim 3, wherein The pumped-storage energy storage system includes a water intake system (3) of the pumped-storage power station, an underground powerhouse (15) of the pumped-storage power station, an upper reservoir (16) of the pumped-storage power station, a water pressure sensor (17), a tail water system (18) of the pumped-storage power station, and a lower reservoir (19) of the pumped-storage power station; Through the water intake system (3) of the pumped-storage power station, in the direction of water flow from top to bottom, 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. The water pressure sensor (17) is installed on the water conveyance pipeline between the underground powerhouse (15) of the pumped-storage power station and the tail water system (18) of the pumped-storage power station.

7. A method for operating a compressed air energy storage and pumped hydro energy storage coupled variable pressure constant pressure operation system according to any one of claims 1-6, characterized in that, It includes the following steps: By controlling the opening and closing of the water channel automatic cut-off valve (4) installed on the water conveyance pipeline (2), various charge and discharge combination forms of the compressed air energy storage system and the pumped-storage energy storage system are realized; Among them, for the compressed air energy storage system, there are three operating modes, namely: the variable-pressure operating mode of the compressed air energy storage system, the pure constant-pressure operating mode of the compressed air energy storage system, and the variable-pressure coupled constant-pressure operating mode of the compressed air energy storage system.

8. The operating method of the compressed air energy storage and pumped hydro energy storage coupled variable pressure constant pressure operation system according to claim 7, characterized in that For the variable pressure operation mode of the compressed air energy storage system, the waterway automatic cut-off valve (4) is always in the closed state, and it includes the following steps: Step A1, initial state of the energy storage chamber: The energy storage chamber (1) is empty and the gas storage pressure is atmospheric pressure; Step A2, initial energy storage of the energy storage chamber: The inflatable airway valve (10) is opened, the compressor (12) is started, and compressed air enters the energy storage chamber (1) until the air pressure in the energy storage chamber (1) reaches the maximum design pressure, then the inflatable airway valve (10) is closed and the compressor (12) is turned off; Step A3, first energy release of the energy storage chamber: During the peak period of power demand or when the power grid power supply is insufficient, the compressed air energy storage system starts to generate electricity: First stage of power generation: The air release airway valve (11) is opened, and the compressed air in the energy storage chamber (1) flows into the expander (13). The gas expands to drive 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 do work and generate electricity; during the power generation process of the expander (13), the compressed air in the energy storage chamber (1) gradually decreases, and the air pressure in the energy storage chamber (1) gradually decreases; Second stage of power generation: When the pressure in the energy storage chamber (1) drops to the lower limit of the rated operating pressure of the first cylinder of the expander, a supplementary 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 supplementary air supply state, completing the variable pressure operation power generation stage of the expander (13) until the pressure in the energy storage chamber (1) reaches the design lower limit pressure, and the air release airway valve (11) is closed, and the power generation ends; Step A4, second energy storage of the energy storage chamber: During the low peak period when the power supply is in excess, the compressed air energy storage system starts the charging function; The inflatable airway valve (10) is opened, the compressor (12) is started to work, and compressed air enters the energy storage chamber (1). At this time, the air in the energy storage chamber (1) is in a pressure rising process. When the air pressure in the energy storage chamber (1) reaches the maximum design pressure, the inflatable airway valve (10) is closed and the compressor (12) stops working to complete the energy storage; Steps A3 and A4 are cycled to realize the variable pressure operation of the compressed air energy storage system.

9. The operating method of the compressed air energy storage and pumped storage coupled variable pressure and constant pressure operation system according to claim 7, characterized in that The pure constant pressure operation mode of the compressed air energy storage system includes the following steps: Step B1, initial state of the energy storage chamber: The energy storage chamber (1) is empty and the gas storage pressure is atmospheric pressure; Step B2, initial energy storage of the energy storage chamber: The inflatable airway valve (10) is opened, the compressor (12) is started, and compressed air enters the energy storage chamber (1). The air pressure in the energy storage chamber (1) continuously rises. When the gas storage air pressure in the energy storage chamber (1) is the same as the water pressure monitored by the water pressure sensor (17), the inflatable airway valve (10) is closed and the compressor (12) is turned off; Step B3, first energy release of the energy storage chamber: During the peak period of power demand or when the power grid power supply is insufficient, the compressed air energy storage system starts to generate electricity: The water channel automatic cut-off valve (4) opens, and the water in the upper reservoir (16) of the pumped-storage power station enters the energy storage chamber (1) through the water diversion system (3) of the pumped-storage power station. The air release airway valve (11) opens, and the compressed air in the energy storage chamber (1) flows into the expander (13). The gas expands to push the expander (13) to generate electricity. Due to the basically constant water head difference, the expander (13) performs constant-pressure expansion work to discharge electricity; After the water level in the energy storage chamber (1) reaches the designed highest water level (7) of the energy storage chamber, the water channel automatic cut-off valve (4) automatically closes, and the air release airway valve (11) closes. The energy release is completed, and the constant-pressure operation power generation stage of the expander (13) is realized; Step B4. Second energy storage of the energy storage chamber: During the low-peak period with an oversupply of power, the compressed air energy storage system starts the energy storage function; The air charging airway valve (10) opens, the water channel automatic cut-off valve (4) opens, the compressor (12) starts to work, and continuously compresses air into the energy storage chamber (1). The water in the energy storage chamber (1) is gradually pressed into the upper reservoir (16) of the pumped-storage power station. When the water level in the energy storage chamber (1) reaches the designed lowest water level (8) of the energy storage chamber, the compressor (12) stops working, and the energy storage is completed; Steps B3 and B4 are cycled to realize the pure constant-pressure operation of the compressed air energy storage system.

10. The operation method of the compressed air energy storage and pumped storage coupled variable pressure constant pressure operation system according to claim 7, characterized in that, The variable-pressure coupled constant-pressure operation mode of the compressed air energy storage system includes the following steps: Step C1. Original state of the energy storage chamber: The energy storage chamber (1) is empty, and the gas storage pressure is atmospheric pressure; Step C2. Initial energy storage of the energy storage chamber: The air charging airway valve (10) opens, the compressor (12) starts, and compressed air enters the energy storage chamber (1) until the air pressure in the energy storage chamber (1) reaches the maximum designed pressure. The air charging airway valve (10) closes, and the compressor (12) closes; Step C3. First energy release of the energy storage chamber: During the peak power demand period or when the power grid power supply is insufficient, the compressed air energy storage system starts to generate electricity: First power generation stage: The air release airway valve (11) opens, and the compressed air in the energy storage chamber (1) flows into the expander (13). The gas expands to push 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 do work and generate electricity; during the power generation process of the expander (13), the compressed air in the energy storage chamber (1) gradually decreases, and the air pressure in the energy storage chamber (1) gradually decreases; Second power generation stage: When the pressure in the energy storage chamber (1) drops to the lower limit of the rated operating pressure of the first cylinder of the expander, a supplementary air supply mode is adopted for operation. 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, it is in a supplementary air supply state, and the variable-pressure operation power generation stage of the expander (13) is completed; In the third stage of power generation, as power is generated in the second stage, the air pressure in the energy storage chamber (1) continuously decreases. When the air storage pressure in the energy storage chamber (1) is the same as the water pressure monitored by the water pressure sensor (17), the water channel automatic cut-off valve (4) opens, and the water in the upper reservoir (16) of the pumped-storage power station enters the energy storage chamber (1) through the water diversion system (3) of the pumped-storage power station. The energy storage chamber (1) realizes the coexistence of water and gas, and the expander (13) performs constant-pressure expansion work to discharge electricity; When the water level in the energy storage chamber (1) reaches the designed maximum water level (7) of the energy storage chamber, the water channel automatic cut-off valve (4) automatically closes, and the air release airway valve (11) closes to stop discharging, realizing the constant-pressure operation power generation stage of the expander (13); Step C4: Second charging and energy storage of the energy storage chamber: During the low peak period of over-abundant power supply, the compressed air energy storage system starts the charging and energy storage function. First charging stage: The air charging airway valve (10) opens, and the compressor (12) starts to work. When the air storage pressure in the energy storage chamber ≥ the head difference pressure, the water channel automatic cut-off valve (4) opens, and compressed air is continuously supplied to the energy storage chamber (1). The water in the energy storage chamber (1) is gradually pressed into the upper reservoir (16) of the pumped-storage power station. When the water level in the energy storage chamber (1) reaches the designed minimum water level (8) of the energy storage chamber, the compressor (12) pauses working, and the water channel automatic cut-off valve (4) closes; Second charging stage: After the water channel automatic cut-off valve (4) closes, the compressor (12) continues to work. At this time, the air in the energy storage chamber (1) is in the process of pressure increase. When the air pressure in the energy storage chamber (1) reaches the maximum designed pressure, the air charging airway valve (10) closes, and the compressor (12) stops working to complete energy storage; Steps C3 and C4 are cycled to realize the coupled operation of variable pressure and constant pressure of the compressed air energy storage system.

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