Reactive compensation method and device for compressed air energy storage power station

Abstract

The invention discloses a reactive compensation method and device for a compressed air energy storage power station, and the method is applied to the compressed air energy storage power station, and comprises the steps: starting a multi-stage motor based on a preset time sequence, and enabling the motor to be used for controlling a compressor; determining a first compensation parameter of each motor of the multi-stage motor, wherein the first compensation parameter is used for representing the reactive power output capability of each motor; a first loss parameter of the compressed air energy storage power station is obtained, the first loss parameter comprises the reactive power demand of a target motor and the reactive power demand of auxiliary power, and the target motor comprises at least one motor. When air is compressed, the synchronous motor serves as a reactive power supply to supplement reactive power consumption of the asynchronous motor and auxiliary power; during expansion power generation, the synchronous generator serves as a reactive power supply to supplement reactive power consumption of auxiliary power.

Description

Technical Field

[0001] The present application relates to the technical field of compressed air energy storage, and in particular to a reactive power compensation method and device for a compressed air energy storage power station. Background Art

[0002] With the transformation of the global energy structure and the large-scale access of wind and solar renewable energy to the grid, the stability and regulation capacity of the power system are facing unprecedented challenges. Compressed air energy storage power stations, as an emerging energy storage technology, have the advantage of cross-time and space regulation of "source-load" matching, and have shown important application value in the context of high-proportion intermittent renewable energy power generation and grid connection.

[0003] When compressed air energy storage power station is compressing air, it needs a lot of reactive power to establish and maintain the rotating magnetic field during startup and operation; when expanding and generating electricity, its energy storage power station's inductive load will also consume a lot of reactive power in the system. In order to compensate for the reactive power consumption of the energy storage power station in the compression and expansion stages and improve the power factor of the power supply system, the conventional practice is to set up a reactive compensation device.

[0004] Traditional reactive power compensation devices, such as capacitors and reactors, can achieve reactive power balance to a certain extent, but they take up a lot of space and have high installation and maintenance costs. In addition, these devices usually require separate additional settings, which increases the complexity and operating costs of the power station electrical system. Summary of the invention

[0005] The purpose of the embodiment of the present application is to provide a reactive power compensation method, which is applied to a compressed air energy storage power station. The method includes: Based on a preset timing, a multi-stage electric motor is started, wherein the electric motor is used to control the compressor; Determining a first compensation parameter of the primary motor, wherein the first compensation parameter is used to characterize the ability of the primary motor to output reactive power; Acquire a first loss parameter of the compressed air energy storage power station, wherein the first loss parameter includes a reactive power requirement of a target motor and a reactive power requirement of the factory power supply, and the target motor includes at least one of the motors; Based on the first compensation parameter and the first loss parameter, it is determined that the first loss parameter of the compressed air energy storage power station is compensated by at least the primary motor.

[0006] As an optional embodiment, the determining, based on the first compensation parameter and the first loss parameter, of compensating the first loss parameter of the compressed air energy storage power station by at least one of the motors includes: comparing the first compensation parameter and the first loss parameter; When it is determined that the first compensation parameter is greater than the first loss parameter, it is determined that the first loss parameter of the compressed air energy storage power station is compensated by the first-stage motor, wherein the type parameter of the first-stage motor is different from the type parameters of the other motors.

[0007] As an optional embodiment, the method further includes: In the case where it is determined that the first compensation parameter is less than the first loss parameter, determining a second compensation parameter of a secondary motor adjacent to the primary motor; Determining a comprehensive compensation parameter based on the first compensation parameter and the second compensation parameter; comparing the comprehensive compensation parameter with the first loss parameter; When it is determined that the comprehensive compensation parameter is greater than the first loss parameter, it is determined that the first loss parameter of the compressed air energy storage power station is compensated by the first-stage motor and the second-stage motor, wherein the type parameter of the first-stage motor is the same as the type parameter of the second-stage motor, and the type parameters of the first-stage motor and the second-stage motor are different from the type parameters of the other motors.

[0008] As an optional embodiment, the determining of compensating the first loss parameter of the compressed air energy storage power station by at least the first-stage motor includes at least one of the following stages: a starting phase of the target motor; The target motor starts and then switches to operation; The operating phase of the target motor.

[0009] As an optional embodiment, the method further includes: During the compression phase of the compressed air energy storage power station, a first compensation parameter of the compressed air energy storage power station is compensated by at least one of the electric motors, and during the expansion phase of the compressed air energy storage power station, the first compensation parameter of the compressed air energy storage power station is compensated by a generator, wherein the generator and the electric motor do not operate simultaneously.

[0010] The purpose of the embodiment of the present application is to provide a reactive power compensation device for a compressed air energy storage power station, the device is used to perform the aforementioned method, and the device includes: The main transformer, whose high-voltage side is connected to the grid; A generator set, the outlet side of which is connected to the low-voltage side of the main transformer; A deep current limiting device, whose input end is connected between the low voltage side of the main transformer and the outlet side of the generator set, for adjusting the current; A busbar, the input end of which is connected to the output end of the depth current limiting device; A compressor unit is connected to the bus bar, and the compressor unit comprises: A plant transformer connected to the busbar; A plurality of compressors are respectively connected to the busbar; A plurality of motors, each of which is connected to the corresponding compressor, wherein the plurality of motors include at least one motor for reactive power compensation, and the motor for reactive power compensation is of a different type from the other motors; A variable frequency soft starting device, whose input end is connected to the bus, and whose output end is respectively connected to the plurality of motors, is used for starting the motors.

[0011] As an optional embodiment, it further includes a load group, wherein the load group includes: A plant transformer connected to the busbar; A plurality of loads are respectively connected to the busbars.

[0012] As an optional embodiment, the busbar includes: A compressor unit busbar connected to the compressor unit; A load group busbar connected to the load group; A busbar connecting circuit breaker is arranged between the compressor group busbar and the load group busbar, and is used to disconnect the compressor group busbar and the load group busbar.

[0013] As an optional embodiment, it also includes: A backup power supply, whose output end is connected to the load group bus through a backup power supply circuit breaker, is used to supply power to the load group.

[0014] The purpose of the embodiment of the present application is to provide a reactive power compensation device for a compressed air energy storage power station, the device is used to perform the aforementioned method, and the device includes: A plurality of motors, including at least one motor for reactive power compensation, wherein type parameters of the motor for reactive power compensation are different from type parameters of other motors; A plurality of compressors are respectively connected to the corresponding motors, and the air outlet of any compressor is connected to the air inlet of the compressor of the next stage; An air storage tank connected to the air outlet of the final compressor; A plurality of expanders connected to the gas outlet end of the gas storage tank; A plurality of heat exchangers, wherein the inlet ends of some of the heat exchangers are respectively connected to the gas outlet ends of the corresponding compressors, and the outlet ends thereof are connected to the gas inlet end of the compressor of the next stage, and the inlet ends of another part of the heat exchangers are connected to the gas outlet end of the gas storage tank or the gas outlet end of the expander, and the outlet ends thereof are connected to the gas inlet end of the corresponding expander; a generator connected to the final-stage expander; During the compression stage, the motor drives the compressor to operate, and the high-pressure compressed air prepared by the compressor is stored in the air storage tank; During the expansion stage, the high-pressure compressed air in the gas storage tank is heated by the heat exchanger and then introduced into the expander to perform work, and the expander drives the generator to operate.

[0015] The beneficial effects of the embodiments of the present application are: In the present application, when compressing air, the synchronous motor serves as a reactive power source to supplement the reactive power consumption of the asynchronous motor and the factory power supply; when expanding and generating electricity, the synchronous generator serves as a reactive power source to supplement the reactive power consumption of the factory power supply.

[0016] The present application configures synchronous motors in compressed air energy storage power stations, and does not require a separate reactive power compensation device, which can reduce equipment investment and installation and maintenance costs, reduce building space and simplify system structure. In addition, if the reactive power demand is large during power station operation, the type of motor can be changed to increase the number of synchronous motors, thereby increasing the reactive power supply capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flowchart of a reactive power compensation method according to an embodiment of the present application; Figure 2 This is a flowchart of step S4 of the reactive power compensation method according to an embodiment of the present application; Figure 3 A schematic diagram of the structure of a reactive power compensation device according to an embodiment of the present application; Figure 4 The local structure of the reactive power compensation device of the embodiment of the present application is shown in FIG. Figure 1 ; Figure 5 The local structure of the reactive power compensation device of the embodiment of the present application is shown in FIG. Figure 2 ; Figure 6 A schematic structural diagram of another reactive power compensation device according to an embodiment of the present application; Figure 7 This is a schematic diagram of the structure of the generator and excitation device according to an embodiment of the present application.

[0018] Reference numerals: Main exciter; 2. Auxiliary exciter; 3. Rotating rectifier; 4. Synchronous motor; 5. Asynchronous motor; 6. Factory transformer; 7. Main transformer; 8. Generator; 9. Frequency conversion soft start device; 10. Frequency conversion device circuit breaker; 11. Motor circuit breaker; 12. Compressor circuit breaker; 13. Deep current limiting device; 14. Motor clutch; 15. Generator clutch; 16. Current transformer; 17. Voltage transformer; 18. Heat exchanger; 19. Compressor; 20. Gas storage tank; 21. Expander; 22. Demagnetization switch; 23. Main transformer high-voltage side circuit breaker; 24. Generator outlet circuit breaker; 25. Standby power circuit breaker; 26. Busbar connection circuit breaker. DETAILED DESCRIPTION

[0019] Various aspects and features of the present application are described herein with reference to the accompanying drawings.

[0020] It should be understood that various modifications may be made to the embodiments of the present application. Therefore, the above description should not be considered as limiting, but only as an example of an embodiment. Other modifications within the scope and spirit of the present application will occur to those skilled in the art.

[0021] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present application and, together with the general description of the present application given above and the detailed description of the embodiments given below, serve to explain the principles of the present application.

[0022] These and other characteristics of the present application will become apparent from the following description of a preferred form of embodiment given as a non-limiting example with reference to the accompanying drawings.

[0023] It should also be understood that although the present application has been described with reference to some specific examples, those skilled in the art will be able to readily implement many other equivalent forms of the present application.

[0024] The above and other aspects, features and advantages of the present application will become more apparent in view of the following detailed description when taken in conjunction with the accompanying drawings.

[0025] Specific embodiments of the present application are described hereinafter with reference to the accompanying drawings; however, it should be understood that the embodiments applied for are merely examples of the present application, which may be implemented in a variety of ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that obscure the present application. Therefore, the specific structural and functional details applied for herein are not intended to be limiting, but merely serve as a basis and representative basis for the claims to teach those skilled in the art to use the present application in a variety of ways with substantially any suitable detailed structure.

[0026] This specification may use the phrases "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments," all of which may refer to one or more of the same or different embodiments according to the present application.

[0027] The embodiment of the present application provides a reactive power compensation method, which is applied to a compressed air energy storage power station, such as Figure 1 As shown, the method includes: S1. Based on a preset timing, a multi-stage motor is started, and the motor is used to control the compressor 19. Each stage motor controls a compressor 19, so that the compressor 19 can compress the air into high-pressure compressed air. The multi-stage motor can be sequentially set as a first-stage motor, a second-stage motor, a third-stage motor, and finally a motor.

[0028] S2. Determine a first compensation parameter of the primary motor, wherein the first compensation parameter is used to characterize the ability of the primary motor to output reactive power. The first compensation parameter of the primary motor depends on the rated capacity of the motor, the type of the motor, the load characteristics of the motor, and the control method of the motor.

[0029] S3. Obtain a first loss parameter of the compressed air energy storage power station, wherein the first loss parameter includes a reactive power requirement of a target motor and a reactive power requirement of factory electricity, and the target motor includes at least one of the motors.

[0030] The reactive power demand of the target motor includes the reactive power demand of the synchronous motor 4 itself and the auxiliary system, and the factory power includes the electrical equipment in the compressed air energy storage power station, such as factory lighting, water pumps and heaters.

[0031] The target motor is at least one motor of the multi-stage motor started according to a preset timing, for example, the target motor is the primary motor, or the target motor is the primary motor and the secondary motor.

[0032] S4. Based on the first compensation parameter and the first loss parameter, determine to compensate the first loss parameter of the compressed air energy storage power station by at least the first-stage motor. According to actual conditions, compensation can be performed only by the first-stage compressor 19, or by the first-stage motor and the second-stage motor, and so on.

[0033] In this embodiment, firstly, the multi-stage motors are started according to a preset timing, and these motors control the compressor 19. Then, according to the first compensation parameter of the first-stage motor and the first loss parameter of the compressed air energy storage power station, it is determined which motors are used to compensate the first compensation parameter.

[0034] In the reactive power compensation of the compressed air energy storage power station, the present application enables the compressed air energy storage power station to only be equipped with a synchronous motor 4, and does not need to set up a separate reactive power compensation device, which can reduce equipment investment and installation and maintenance costs, reduce building space and simplify the system structure.

[0035] For example, when the compressed air energy storage power station starts compressing air, it starts the first-stage motor and switches to industrial frequency operation after the startup is completed. During this process, the first-stage motor can compensate for the reactive power consumption of itself and the auxiliary system of the compressor at this stage on-site, and also compensate for the reactive power loss of the factory electricity.

[0036] After the primary motor switches to industrial frequency operation, the secondary motor is started, and after the startup is completed, it switches to industrial frequency operation. During this process, the primary motor can locally compensate for the reactive power loss of the secondary motor and its compressor auxiliary system. At this time, the compensation object is the reactive power loss of the primary motor-secondary motor, and the reactive power loss of the factory power is also compensated.

[0037] After the secondary motor switches to industrial frequency operation, the tertiary motor is started, and after the startup is completed, it switches to industrial frequency operation. During this process, the primary motor can locally compensate for the reactive power loss of the tertiary motor and its own compressor auxiliary system. At this time, the compensation object is the reactive power loss of the primary motor-tertiary motor and its auxiliary system, and the reactive power loss of the factory power is also compensated.

[0038] The compensation of other motors is the same as that of the aforementioned motors. That is, the first motor is set as a synchronous motor 4, and the second to final motors are set as asynchronous motors 5. When the first motor is set as a synchronous motor 4, and the reactive power provided by it cannot meet the reactive power loss of the compressed air energy storage power station, the second motor is also set as a synchronous motor 4. If the reactive power loss still cannot be met, the motors are set as synchronous motors 4 step by step. The present application can change the type of motor according to the actual reactive power demand at each stage to meet the requirements.

[0039] As an optional embodiment, Figure 2 As shown, based on the first compensation parameter and the first loss parameter, determining to compensate the first loss parameter of the compressed air energy storage power station by at least one of the motors includes: S41, comparing the first compensation parameter and the first loss parameter; S42. When it is determined that the first compensation parameter is greater than the first loss parameter, determine to compensate the first loss parameter of the compressed air energy storage power station by the first-stage motor, wherein the type parameter of the first-stage motor is different from the type parameters of the other motors.

[0040] In this embodiment, if the first compensation parameter of the primary motor is greater than the first loss parameter of the compressed air energy storage power station, the primary motor is used for compensation. For example, the primary motor has a reactive power output capacity of 120 kVar, and the first loss parameter is 100 kVar. Since the compensation capacity of the primary motor is greater than the demand, the primary motor can fully compensate for the reactive loss of the compressed air energy storage power station.

[0041] This application can ensure that the power station can effectively compensate for reactive power losses and improve the operating efficiency and stability of the power station under the cooperation of different motors.

[0042] As an optional embodiment, Figure 2 As shown, the method also includes: S43, when it is determined that the first compensation parameter is less than the first loss parameter, determining a second compensation parameter of a secondary motor adjacent to the primary motor; S44, determining a comprehensive compensation parameter based on the first compensation parameter and the second compensation parameter; S45, comparing the comprehensive compensation parameter and the first loss parameter; S46. When it is determined that the comprehensive compensation parameter is greater than the first loss parameter, determine to compensate the first loss parameter of the compressed air energy storage power station by the first-stage motor and the second-stage motor, wherein the type parameter of the first-stage motor is the same as the type parameter of the second-stage motor, and the type parameters of the first-stage motor and the second-stage motor are different from the type parameters of the other motors.

[0043] For example, the primary motor and the secondary motor are both synchronous motors 4 , and the target motor is an asynchronous motor 5 .

[0044] In this embodiment, if the compensation capacity of the first-stage motor is not sufficient to meet the needs of the compression-controlled energy storage power station, it is necessary to determine the second compensation parameters of the adjacent secondary motor and compare them with the first compensation parameters of the first-stage motor to determine whether the needs of the compression-controlled energy storage power station can be met.

[0045] The type of the motor of the present application changes according to the compensation capability provided or the object to be compensated. For example, the secondary motor is a synchronous motor 4 when compensating the tertiary motor, but is an asynchronous motor 5 when receiving compensation from the primary motor.

[0046] If the compensation parameter of the primary motor is 80 kVar, the first loss parameter is 120 kVar, and the compensation parameter of the secondary motor is 80 kVar, then the primary motor and the secondary motor are required to jointly meet the requirement of the first loss parameter.

[0047] The present application provides a flexible compensation strategy, allowing multiple motors to work together to meet the reactive power demand of the compression-controlled energy storage power station. Therefore, if the reactive power demand of the compression-controlled energy storage power station is large, the type of motor can be changed to increase the reactive power output capability.

[0048] As an optional embodiment, the determining of compensating the first loss parameter of the compressed air energy storage power station by at least the first-stage motor includes at least one of the following stages: The target motor starts in a starting phase; the target motor starts and then switches to operation; and the target motor operates in an operation phase.

[0049] Specifically, when the target motor is a primary motor, the reactive power consumption of the primary motor can be compensated during the startup, switching and operation phases of the primary motor. In addition, the reactive power loss of the factory power can also be compensated at any phase.

[0050] In this embodiment, the motor may require more reactive power to overcome the initial resistance when starting, and may require less reactive power during the operation stage. Therefore, the present application allows for optimized compensation at different stages of the motor to adapt to the power requirements of the motor at different stages and improve overall efficiency.

[0051] As an optional embodiment, the method further includes: During the compression phase of the compressed air energy storage power station, the first compensation parameter of the compressed air energy storage power station is compensated by at least one of the motors, and during the expansion phase of the compressed air energy storage power station, the first compensation parameter of the compressed air energy storage power station is compensated by the generator 8, wherein the generator 8 and the motor do not operate simultaneously. The generator 8 is a synchronous generator 8.

[0052] In this embodiment, in the compression stage, at least the first-stage motor is used for reactive power compensation, that is, the synchronous motor 4 can be used as a reactive power source to supplement the reactive power consumption of itself, the asynchronous motor 5 and the factory power. In the expansion stage, the generator 8 is used to supplement the reactive loss of the compressed air energy storage power station, that is, the synchronous generator 8 can also be used as a reactive power source to supplement the reactive power consumption of the compressed air energy storage power station.

[0053] Furthermore, the motor and the generator 8 will not operate at the same time during the compression phase or the expansion phase. The motor and the generator 8 are both idle at any phase and can serve as reactive power sources that complement each other. During the compression phase, the generator 8 is idle and can also compensate for the reactive power loss generated during the compression phase. During the expansion phase, the motor is idle and can also compensate for the reactive power loss generated during the expansion phase.

[0054] Specifically, the generator 8 is in an idle state during the compression phase, that is, it does not perform the main power generation task during this phase. The generator 8 can compensate for this part of the reactive power loss by adjusting its own excitation and other parameters. That is, although the generator 8 does not work at full capacity to generate electricity, it can provide reactive power to maintain the electromagnetic balance of the system like an "auxiliary power supply".

[0055] When the compressor 19 and other equipment are running in the compression stage, reactive power loss will be generated. The idle generator 8 can help stabilize the voltage of the power grid and reduce the impact of reactive power loss.

[0056] The motor is in an idle state during the expansion phase, that is, the motor does not output mechanical work and does not drive related equipment to operate.

[0057] The expansion phase also generates reactive power losses, which can be compensated by idle motors. The motor can utilize its own inductance, capacitance and other characteristics, and through appropriate control measures, it can feed back reactive power to the grid, help balance the reactive power in the system, reduce the reactive power loss of the entire system, and thus improve the efficiency and stability of the power system.

[0058] The present application can ensure that the power station can maintain the required reactive power level under any circumstances, thereby enhancing the reliability of use.

[0059] For example, during expansion power generation, the active power and reactive power of the generator 8 can be adjusted by the magnitude of the excitation current of the generator 8 to meet different working conditions. The magnitude of the excitation current of the generator 8 can be adjusted manually or automatically by the excitation device.

[0060] The embodiment of the present application provides a reactive power compensation device for a compressed air energy storage power station, the device is used to perform the aforementioned method, such as Figure 4-Figure 7 As shown, the device includes a main transformer 7, a generator set, a deep current limiting device 13, a busbar and a compressor set.

[0061] The high voltage side of the main transformer 7 is connected to the power grid via a main transformer high voltage side circuit breaker 23 , and the outlet side of the generator set is connected to the low voltage side of the main transformer 7 via a generator outlet circuit breaker 24 .

[0062] The input end of the deep current limiting device 13 is connected between the low voltage side of the main transformer 7 and the outlet side of the generator set for adjusting the current. The input end of the busbar is connected to the output end of the deep current limiting device 13 .

[0063] The compressor unit is connected to the busbar, and includes a plant transformer 6, multiple compressors 19, multiple motors and a variable frequency soft start device 9.

[0064] The plant transformer 6 is connected to the plant transformer circuit breaker (such as Figure 3 QF1 in the figure is connected to the bus, and the multiple compressors 19 are connected to the bus through compressor circuit breakers 12 (such as Figure 3 QF2-QF5) in the circuit are connected to the bus, and the multiple motors are connected to the corresponding compressors 19 respectively.

[0065] The input end of the variable frequency soft start device 9 is connected to the variable frequency device circuit breaker 10 (such as Figure 3 QF5 in the figure is connected to the busbar, and its output end is connected to the busbar through a motor circuit breaker 11 (such as Figure 3 QF7-QF10) in the inverter are connected to the plurality of motors respectively. The motors are started in sequence by the variable frequency soft start device 9, and then the compressor 19 is started. After the start is completed, the motor circuit breaker 11 between the variable frequency soft start device 9 and the motor is disconnected, and the compressor circuit breaker 12 between the compressor 19 and the bus is closed, so that the motor is switched to the power frequency operation.

[0066] As an optional embodiment, a load group is also included, and the load group includes another plant transformer 6 and multiple loads. The plant transformer 6 is connected to the plant transformer circuit breaker (such as Figure 3 QF11 in the figure) is connected to the busbar, and multiple loads are connected through load circuit breakers (such as Figure 3 QF12-QF15) in the circuit are connected to the busbar.

[0067] As an optional embodiment, the bus includes a compressor group bus, a load group bus and a bus tie circuit breaker 26. The compressor group bus is connected to the compressor group, and the load group bus is connected to the load group. The bus tie circuit breaker 26 is provided between the compressor group bus and the load group bus, and is used to disconnect the compressor group bus and the load group bus.

[0068] As an optional embodiment, a backup power supply is further included, and the output end of the backup power supply is connected to the load group bus through a backup power supply circuit breaker 25 to supply power to the load group.

[0069] In some embodiments, the generator set includes a generator 8 and an excitation device. The excitation device is composed of a rotating rectifier 3, a three-phase main exciter 1, a three-phase auxiliary exciter 2, a generator excitation winding, a terminal voltage / current transformer 16, and an automatic voltage regulator. The generator 8 adjusts the excitation current through the excitation device to change the active power and reactive power output by the generator 8. This content is a technical means known to those skilled in the art, so it will not be repeated in this application.

[0070] Exemplarily, the first-stage motor is a synchronous motor 4 , the second-stage to fourth-stage motors are all asynchronous motors 5 , and the generator 8 of the generator set is a synchronous generator 8 .

[0071] When the compressed air energy storage power station starts compressing air, the high-voltage side circuit breaker of the main transformer 7 is closed, the busbar circuit breaker CB3 is closed, and the 10kV compressor unit bus and the auxiliary power bus of the energy storage power station are powered through the deep current limiting device 13. At the same time, the frequency conversion device circuit breaker 10 is closed to connect the power supply of the frequency conversion soft start device 9, and then the motor circuit breaker 11 (such as Figure 3 QF7 in the circuit) to start the first-stage motor (such as Figure 3 1YSJ in it).

[0072] At the beginning of the start, the voltage, frequency and phase of the primary motor are adjusted by the variable frequency soft start device 9 and the excitation device. When the voltage, frequency and phase of the primary motor and the bus are consistent, the frequency conversion switches the working frequency and closes the compressor circuit breaker 12 (such as Figure 3 QF2 in the circuit breaker 11 (as Figure 3 QF7 in the circuit is used to switch the first-stage motor to industrial frequency operation. During this process, the first-stage motor can compensate for the reactive power consumption of itself and the auxiliary system of the compressor at this level, as well as the reactive power consumption of the factory electricity.

[0073] After the primary motor switches to industrial frequency operation, the variable frequency soft start device 9 closes the motor circuit breaker 11 (such as Figure 3 QF8 in the circuit) controls the voltage and frequency of the secondary motor to smoothly start the secondary motor (such as Figure 3 2YSJ in the figure), after the secondary motor is started, close the compressor circuit breaker 12 corresponding to the secondary motor (such as Figure 3 QF3 in the circuit breaker 11 (as Figure 3 QF8 in the circuit) is used to switch the secondary motor to industrial frequency operation. During this process, the primary motor can also compensate for the reactive power loss of the secondary motor and its compressor auxiliary system and the reactive power consumption of the factory electricity.

[0074] After the secondary motor switches to industrial frequency operation, the variable frequency soft start device 9 closes the motor circuit breaker 11 (such as Figure 3 QF9 in the circuit) controls the voltage and frequency of the three-stage motor to smoothly start the three-stage motor (such as Figure 3 3YSJ in the figure), after the startup is completed, close the compressor circuit breaker 12 corresponding to the three-level motor (such as Figure 3 QF4 in the circuit breaker 11 (as Figure 3QF9 in the circuit) is used to switch the third-stage motor to industrial frequency operation. During this process, the first-stage motor can also compensate for the reactive power loss of the third-stage motor and its compressor auxiliary system as well as the reactive power consumption of the factory electricity.

[0075] After the three-stage motor is switched to industrial frequency operation, the variable frequency soft start device 9 closes the motor circuit breaker 11 (such as Figure 3 QF10 in the figure) controls the voltage and frequency of the four-stage motor to smoothly start the four-stage motor (such as Figure 3 4YSJ), driving the compressor 19 to continue to increase the speed and frequency conversion operation. During this process, the first-stage motor can also compensate for the reactive power loss of the fourth-stage motor and its auxiliary system and the reactive power consumption of the factory electricity.

[0076] When the energy storage power station is required to generate electricity during the peak period of electricity consumption, the circuit breaker CB1 of the main transformer 7 is closed, and the 10kV plant power bus is supplied with power through the deep current limiting device 13, and the two plant transformer circuit breakers (such as Figure 3 QF1 and QF11) and busbar tie circuit breaker 26 are used as the power source for starting the generator set, and the backup power circuit breaker 25 is in the open position.

[0077] At this time, the active power and reactive power of the generator 8 can be adjusted by the magnitude of the excitation current of the generator 8 to meet different working conditions. The magnitude of the excitation current can be adjusted manually or automatically by the excitation device.

[0078] The embodiment of the present application provides a reactive power compensation device for a compressed air energy storage power station, the device is used to perform the aforementioned method, such as Figure 6 As shown, the device includes multiple electric motors, multiple compressors 19 , multiple heat exchangers 18 , a gas storage tank 20 , multiple expanders 21 and a generator 8 .

[0079] The plurality of motors include at least one motor for reactive power compensation, and the type parameters of the motor for reactive power compensation are different from the type parameters of the other motors. The plurality of motors can be sequentially set as a first-stage motor, a second-stage motor, a third-stage motor, and finally a motor.

[0080] The plurality of compressors 19 are respectively connected to the corresponding motors, and the air outlet of any compressor 19 is connected to the air inlet of the compressor 19 at the next stage.

[0081] The gas storage tank 20 is connected to the gas outlet end of the final compressor 19 , the plurality of expanders 21 are connected to the gas storage tank 20 , and the generator 8 is connected to the final expander 21 .

[0082] There are multiple heat exchangers 18, wherein the inlet ends of some of the heat exchangers 18 are connected to the outlet ends of the corresponding compressors 19, and the outlet ends thereof are connected to the inlet end of the compressor 19 of the next stage, and the inlet ends of other part of the heat exchangers 18 are connected to the outlet end of the gas storage tank 20 or the outlet end of the expander 21, and the outlet ends thereof are connected to the inlet end of the corresponding expander 21.

[0083] During the compression stage, the motor drives the air compressor 19 to operate, and the high-pressure compressed air prepared by the air compressor 19 is stored in the air storage tank 20. During the expansion stage, the high-pressure compressed air in the air storage tank 20 is heated by the heat exchanger 18 and then introduced into the expander 21 to perform work, and the expander 21 drives the generator 8 to operate.

[0084] Specifically, the present application is provided with 4 electric motors, 4 compressors 19, 4 heat exchangers 18 and 2 expanders 21, and the gas flow directions in the compression stage and the expansion stage are respectively at different levels.

[0085] During the compression stage, electric motors of different levels are connected to corresponding compressors 19, and a first-stage heat exchanger 18 is provided between the first-stage compressor 19 and the second-stage compressor 19, a second-stage heat exchanger 18 is provided between the second-stage compressor 19 and the third-stage compressor 19, the outlet end of the third-stage compressor 19 is connected to the inlet end of the fourth-stage compressor 19, and the outlet end of the fourth-stage compressor 19 is connected to the inlet end of the air storage tank 20.

[0086] During the expansion stage, the outlet end of the gas storage tank 20 is connected to the inlet end of the tertiary heat exchanger 18, the outlet end of the tertiary heat exchanger 18 is connected to the inlet end of the first-stage expansion machine 21, the outlet end of the first-stage expansion machine 21 is connected to the inlet end of the quaternary heat exchanger 18, the outlet end of the quaternary heat exchanger 18 is connected to the inlet end of the secondary expansion machine 21, and the outlet end of the secondary expansion machine 21 is connected to the generator 8.

[0087] like Figure 7 As shown, the generator 8 also includes an excitation device, which consists of a rotating rectifier 3, a three-phase main exciter 1, a three-phase auxiliary exciter 2, a generator excitation winding, a machine-end voltage transformer 17, a machine-end current transformer 16 and an automatic voltage regulator.

[0088] When the high-pressure compressed air released from the gas tank 20 drives the expander 21 to rotate, since the rotating rectifier 3, the generator excitation winding, the main excitation machine 1 rotor winding, and the auxiliary excitation machine 2 permanent magnets are all on the same rotor, the auxiliary excitation machine 2 permanent magnets installed on the rotor will induce the auxiliary excitation machine 2 stator winding to generate three-phase AC power, which is sent to the main excitation machine 1 stator winding after thyristor rectification. The magnetic field generated by the main excitation machine 1 stator winding will induce the main excitation machine 1 rotor winding to generate three-phase AC power, which is rectified by the rotating rectifier 3 to generate DC power and sent to the generator excitation winding. The rotating magnetic field established by the generator excitation winding cuts the generator 8 stator winding, thereby emitting a three-phase current. The start-up demagnetization of the excitation device is controlled by the demagnetization switch 22.

[0089] The signal of the automatic voltage regulator is taken from the excitation power supply of the generator 8 and the auxiliary exciter 2, and is rectified into a DC signal by the thyristor rectifier bridge. The automatic voltage regulator controls the on and off of the insulated gate bipolar transistor (IGBT) by changing the duty cycle of the pulse width modulation (PWM) signal, thereby adjusting the output current of the excitation device to change the size of the active power and reactive power output by the generator 8. Among them, the automatic voltage regulator adopts AC sampling technology, and realizes the measurement of the generator 8 terminal voltage and the generator 8 stator current by collecting the analog signals of the machine-side current transformer 16 and the voltage transformer 17, that is, the measurement of the voltage and current of the stator winding of the generator 8.

[0090] The demagnetization switch 22 is used to connect or disconnect the excitation current of the excitation circuit of the generator 8. When the generator 8 is shut down, the generator output circuit breaker 24 needs to be disconnected to cut off the generator 8 from the power grid and prepare for shutdown. Before disconnecting the generator output circuit breaker 24, the generator 8 may still bear a part of the load, so the working current flowing through the rotor is larger than the excitation current when it is no-load.

[0091] When the generator outlet circuit breaker 24 is disconnected, the generator 8 will be disconnected from the external load and the excitation current will also be cut off. At this time, due to the absence of external load, the speed of the expander 21 will increase. If the demagnetization switch 22 is not continuously opened to cut off the excitation current during this process, the generator 8 will have an overvoltage phenomenon, causing the excitation winding of the generator 8 to be electrically broken down.

[0092] Exemplarily, when the compressed air energy storage power station starts compressing air, the first-stage motor is started, and after the startup is completed, it switches to industrial frequency operation. During this process, the first-stage motor can compensate for the reactive power consumption of itself and the auxiliary system and the reactive power consumption of the factory electricity on site.

[0093] After the primary motor switches to industrial frequency operation, the secondary motor is started and switched to industrial frequency operation after the startup is completed. During this process, the primary motor can compensate for the reactive power loss of the secondary motor and its auxiliary system and the reactive power consumption of the factory electricity on site.

[0094] After the secondary motor switches to industrial frequency operation, the tertiary motor is started, and after the startup is completed, it switches to industrial frequency operation. During this process, the primary motor can locally compensate for the reactive power loss of the tertiary motor and its auxiliary system and the reactive power consumption of the factory electricity. The compensation of other motors is the same as that of the aforementioned motors.

[0095] That is, the first-stage motor is set as a synchronous motor 4, and the second-stage to the final-stage motors are set as asynchronous motors 5. When the reactive power provided by the first-stage motor cannot meet the reactive power loss of the compressed air energy storage power station, the second-stage motor is set as a synchronous motor 4. If the reactive power loss still cannot be met, the motors are set as synchronous motors 4 step by step.

[0096] When the compressed air energy storage power station is needed to generate electricity during peak power consumption, the high-pressure compressed air in the air storage tank 20 is released, and the high-pressure compressed air begins to expand to drive the expander 21. The excitation device of the generator 8 can adjust the excitation current of the generator 8 to generate active power and reactive power to meet the working condition requirements.

[0097] In some embodiments, a motor clutch 14 is provided between the first-stage motor and the first-stage compressor 19 , and a generator clutch 15 is provided between the generator 8 and the second-stage expander 21 .

[0098] The compressed air energy storage power station is divided into two stages: compression charging and expansion power generation. The compression stage and the expansion stage do not operate at the same time. When the compressor 19 or the expander 21 stops, the reactive power compensation function can also be achieved through the following contents: In some embodiments, when the compressor 19 is shut down, the motor clutch 14 between the compressor 19 and the first-stage motor is disengaged, and the first-stage motor is started. The compressor 19 is in a no-load state, and at the same time, the excitation current is adjusted by the excitation device of the first-stage motor to control the output of the reactive power of the first-stage motor, thereby meeting the reactive power balance requirements of the system.

[0099] In addition, if there is no motor clutch 14 between the compressor 19 and the first-stage motor, the compressor 19 idles without load when the first-stage motor is started, and at the same time, the excitation device of the first-stage motor is controlled to adjust the excitation current to control the reactive power output of the first-stage motor.

[0100] In other embodiments, when the expander 21 is shut down, the generator clutch 15 between the expander 21 and the generator 8 is disengaged, and the generator 8 is started. At this time, the generator 8 operates as a motor, and the power grid provides electricity to maintain the rotation of the motor. The excitation device of the generator 8 adjusts the excitation current to control the reactive power output of the generator 8.

[0101] If there is no generator clutch 15 between the expander 21 and the generator 8, the generator 8 is started, the air with a lower pressure in the air storage tank 20 is released and the heat is coupled to keep the generator 8 in a rotating state. At the same time, the excitation current is adjusted by the excitation device of the generator 8 to control the reactive power output of the generator 8, thereby meeting the reactive output requirements of the system.

[0102] In the extreme case of the compression stage, if all motors at each level are synchronous motors 4, the reactive power they generate still cannot meet the reactive loss demand of the compressed air energy storage power station. Releasing part of the energy in the above manner can also control the reactive power output of the generator 8, thereby supplementing the insufficient reactive power demand of the power station.

[0103] However, this method has the disadvantage of losing compressed air and heat during the compression stage, such as the generator clutch 15 between the expander 21 and the generator 8. When the generator clutch 15 is disengaged, the generator 8 operates as a motor, and the power grid is used to keep the generator 8 rotating, thereby achieving the purpose of compensating for the insufficient reactive power demand of the power station by controlling the reactive output of the generator 8. Similarly, during the expansion stage, the reactive power generated by the motor can also be used to meet the reactive power demand of the power station.

[0104] The setting of the clutch improves the utilization rate of the compressed air energy storage power station equipment and increases the flexibility and application scope of the device.

[0105] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. A reactive power compensation method for a compressed air energy storage power station, characterized in that: Applied to a compressed air energy storage power station, the method comprises: Based on a preset timing, a multi-stage electric motor is started, wherein the electric motor is used to control the compressor; Determining a first compensation parameter of the primary motor, wherein the first compensation parameter is used to characterize the ability of the primary motor to output reactive power; Acquire a first loss parameter of the compressed air energy storage power station, wherein the first loss parameter includes a reactive power requirement of a target motor and a reactive power requirement of the factory power supply, and the target motor includes at least one of the motors; Based on the first compensation parameter and the first loss parameter, it is determined that the first loss parameter of the compressed air energy storage power station is compensated by at least the primary motor.

2. The method according to claim 1, characterized in that The step of determining, based on the first compensation parameter and the first loss parameter, to compensate the first loss parameter of the compressed air energy storage power station by at least one of the motors comprises: comparing the first compensation parameter and the first loss parameter; When it is determined that the first compensation parameter is greater than the first loss parameter, it is determined that the first loss parameter of the compressed air energy storage power station is compensated by the first-stage motor, wherein the type parameter of the first-stage motor is different from the type parameters of the other motors.

3. The method according to claim 2, characterized in that The method further comprises: In the case where it is determined that the first compensation parameter is less than the first loss parameter, determining a second compensation parameter of a secondary motor adjacent to the primary motor; Determining a comprehensive compensation parameter based on the first compensation parameter and the second compensation parameter; comparing the comprehensive compensation parameter with the first loss parameter; When it is determined that the comprehensive compensation parameter is greater than the first loss parameter, it is determined that the first loss parameter of the compressed air energy storage power station is compensated by the first-stage motor and the second-stage motor, wherein the type parameter of the first-stage motor is the same as the type parameter of the second-stage motor, and the type parameters of the first-stage motor and the second-stage motor are different from the type parameters of the other motors.

4. The method according to claim 1, characterized in that The determining of compensating the first loss parameter of the compressed air energy storage power station by at least the primary motor comprises at least one of the following stages: a starting phase of the target motor; The target motor starts and then switches to operation; The operating phase of the target motor.

5. The method according to claim 1, characterized in that The method further comprises: During the compression phase of the compressed air energy storage power station, a first compensation parameter of the compressed air energy storage power station is compensated by at least one of the electric motors, and during the expansion phase of the compressed air energy storage power station, the first compensation parameter of the compressed air energy storage power station is compensated by a generator, wherein the generator and the electric motor do not operate simultaneously.

6. A reactive power compensation device for a compressed air energy storage power station, characterized in that: The device is used to perform the method according to any one of claims 1 to 5, and the device comprises: The main transformer, whose high-voltage side is connected to the grid; A generator set, the outlet side of which is connected to the low-voltage side of the main transformer; A deep current limiting device, whose input end is connected between the low voltage side of the main transformer and the outlet side of the generator set, for adjusting the current; A busbar, the input end of which is connected to the output end of the depth current limiting device; A compressor unit is connected to the bus bar, and the compressor unit comprises: A plant transformer connected to the busbar; A plurality of compressors are respectively connected to the busbar; A plurality of motors, each of which is connected to the corresponding compressor, wherein the plurality of motors include at least one motor for reactive power compensation, and the motor for reactive power compensation is of a different type from the other motors; A variable frequency soft starting device, whose input end is connected to the bus, and whose output end is respectively connected to the plurality of motors, is used for starting the motors.

7. The device according to claim 6, characterized in that Also included is a load group, the load group comprising: A plant transformer connected to the busbar; A plurality of loads are respectively connected to the busbars.

8. The device according to claim 7, characterized in that The busbar comprises: A compressor unit busbar connected to the compressor unit; A load group busbar connected to the load group; A busbar connecting circuit breaker is arranged between the compressor group busbar and the load group busbar, and is used to disconnect the compressor group busbar and the load group busbar.

9. The device according to claim 8, characterized in that Also includes: A backup power supply, whose output end is connected to the load group bus through a backup power supply circuit breaker, is used to supply power to the load group.

10. A reactive power compensation device for a compressed air energy storage power station, characterized in that: The device is used to perform the method according to any one of claims 1 to 5, and the device comprises: A plurality of motors, including at least one motor for reactive power compensation, wherein type parameters of the motor for reactive power compensation are different from type parameters of other motors; A plurality of compressors are respectively connected to the corresponding motors, and the air outlet of any compressor is connected to the air inlet of the compressor of the next stage; An air storage tank connected to the air outlet of the final compressor; A plurality of expanders connected to the gas outlet end of the gas storage tank; A plurality of heat exchangers, wherein the inlet ends of some of the heat exchangers are respectively connected to the gas outlet ends of the corresponding compressors, and the outlet ends thereof are connected to the gas inlet end of the compressor of the next stage, and the inlet ends of another part of the heat exchangers are connected to the gas outlet end of the gas storage tank or the gas outlet end of the expander, and the outlet ends thereof are connected to the gas inlet end of the corresponding expander; a generator connected to the final-stage expander; During the compression stage, the motor drives the compressor to operate, and the high-pressure compressed air prepared by the compressor is stored in the air storage tank; During the expansion stage, the high-pressure compressed air in the gas storage tank is heated by the heat exchanger and then introduced into the expander to perform work, and the expander drives the generator to operate.

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