Charging and storage capacity dynamic evaluation method and system of compressed air energy storage system, electronic equipment and storage medium

Abstract

The invention provides a method and a system for dynamically evaluating the charge and storage capacity of a compressed air energy storage system, electronic equipment and a storage medium, and the method comprises the steps: building a simulation model of the compressed air energy storage system, and carrying out a variable working condition test; and fitting to obtain pressure-flow mapping curves of an inlet and an outlet in the air storage device when the compressed air energy storage system operates under various load working conditions, and performing integral calculation on the pressure of the inlet and the outlet of the air storage device to calculate the residual inflation / deflation time, thereby realizing dynamic evaluation on the residual energy storage / release capability of the system. According to the method, the technical problems that the charging and storage capacity evaluation method is incomplete and network storage interaction real-time scheduling is difficult in the operation process of the compressed air energy storage system are solved, and the actual benefits of the energy storage technology in new energy application are further promoted.

Description

Technical Field

[0001] The present invention relates to the field of renewable energy storage technology, and in particular to a method, system, electronic equipment and storage medium for dynamically evaluating the charging and storage capacity of a compressed air energy storage system. Background Art

[0002] At present, more and more renewable energy represented by wind power and photovoltaic power have been connected to the grid. While large-scale renewable energy grid connection provides a large amount of low-carbon clean energy, its inherent uncertainty in power generation capacity also increases the peak-shaving pressure of the power grid. In addition, renewable energy generation, mainly wind power and photovoltaic power, relies on a large number of power electronic equipment. With the increase in the penetration rate of new energy, the total rotational inertia of the power system decreases, which in turn affects the frequency stability of the system.

[0003] In the context of high proportion of renewable energy access and high proportion of power electronic equipment application, energy storage technology has become a key means to ensure energy supply and demand balance and improve energy utilization efficiency. Among them, compressed air energy storage technology has become an important energy storage technology in new energy systems because of its large-scale energy storage potential, which is particularly suitable for the utilization of renewable energy and peak-valley regulation of power grids, and can provide rotational inertia to participate in frequency modulation, thereby effectively improving the stability of the power grid.

[0004] As a type of non-supplementary compressed air energy storage technology, the adiabatic compressed air energy storage system has two working principles: compression energy storage and expansion energy release. In the compression energy storage stage, the system compresses and stores air by driving the compressor through electric energy, and at the same time stores the heat energy generated during the compression process. In the expansion energy release stage, the stored heat energy is transferred back to the high-pressure air through the heat exchanger, and the expanded air drives the turbine to generate electricity. There is no greenhouse gas emission during the operation process, which is a green, clean and efficient energy storage method. However, the operation process of the compressed air energy storage system has a huge time and space span. The air parameters in the air storage device are constantly changing during the operation process, and the real-time evaluation of the system performance is difficult, which will limit the development of efficient operation and optimization technology of the compressed air energy storage system. In the prior art, there are few operating practices of compressed air energy storage systems, lack of operating data accumulation, limited research on the system's remaining energy storage / release capacity during the inflation / deflation process, and the integral characteristics of the charging and storage capacity have not been fully reflected in the research in the field of performance evaluation. It is difficult for compressed air energy storage power stations to provide real-time feedback to the grid side's own remaining energy storage / release capacity. Summary of the invention

[0005] Purpose of the invention: The first purpose of the present invention is to provide a method for dynamically evaluating the storage capacity of a compressed air energy storage system with real-time feedback. The second purpose is to provide a dynamic evaluation system for the storage capacity of a compressed air energy storage system, an electronic device and a storage medium corresponding to the above-mentioned dynamic evaluation method for storage capacity.

[0006] Technical solution: A method for dynamically evaluating the charging and storage capacity of a compressed air energy storage system, comprising the following steps:

[0007] (1) Based on the design parameters of the compressed air energy storage system and the principles of engineering thermodynamics and heat transfer, a simulation model of each device of the compressed air energy storage system is established;

[0008] (2) Connect the interfaces between the simulation models of various devices in the compressed air energy storage system, establish an integrated model of the compressed air energy storage system, and use the variable operating characteristic curves of various devices in the compressed air energy storage system to establish a thermodynamic model of the compressed air energy storage system;

[0009] (3) Conduct variable operating condition tests based on the thermodynamic model of the compressed air energy storage system to obtain a variable operating condition simulation database for the compressed air energy storage system, and use the variable operating condition simulation data to fit the system pressure-flow curve;

[0010] (4) The pressure is integrated using the system pressure-flow curve to obtain the remaining inflation or deflation time of the compressed air energy storage system. The inflation or deflation time is multiplied by the given system load power to obtain the charging or storage capacity of the compressed air energy storage system.

[0011] Specifically, in step (1), the equipment of the compressed air energy storage system includes: a compressor, a turbine, an air storage device, and a heat exchanger.

[0012] Specifically, in step (3), the variable operating condition test includes: for each device of the compressed air energy storage system, simulation experiments are performed on the inflation and deflation processes under different load conditions, and the changes in the air parameters in the air storage device over time during the inflation and deflation processes are simulated by changing the pressure at the inlet and outlet of the air storage device.

[0013] Specifically, in step (3), the spline interpolation method is used to fit the variable operating condition simulation data to obtain the system pressure-flow curve.

[0014] Specifically, in step (4), based on the gas state equation and the mass conservation equation, the pressure is integrated using the system pressure-flow curve, taking the inlet and outlet pressures of the current gas storage device of the system as a reference.

[0015] Specifically, in step (4), the calculation formula for the deflation time is:

[0016]

[0017] Where: t disch is the deflation time, p cavern is the pressure of the gas storage device, p cavern,now is the current outlet pressure of the gas storage device, p cavern,min is the minimum pressure of the gas storage device, V cavernis the volume of the gas storage device, ρ max is the maximum value of the air density in the air storage device, ρ min is the minimum value of the air density in the air storage device, ρ′(p cavern ) is the first derivative of the relationship between air density and air storage device pressure, g disch (p cavern ) is the function of the relationship between air flow and the pressure of the air storage device.

[0018] Specifically, in step (4), the calculation formula for the inflation time is:

[0019]

[0020] Where: t ch is the inflation time, p cavern is the pressure of the gas storage device, p cavern,now is the current outlet pressure of the gas storage device, p cavern,max is the maximum pressure of the gas storage device, V cavern is the volume of the gas storage device, ρ max is the maximum value of the air density in the air storage device, ρ min is the minimum value of the air density in the air storage device, ρ′(p cavern ) is the first derivative of the relationship between air density and air storage device pressure, g ch (p cavern ) is the function of the relationship between air flow and the pressure of the air storage device.

[0021] The present invention also provides a system for dynamically evaluating the storage capacity of a compressed air energy storage system, comprising:

[0022] Equipment model building module: used to build simulation models of various equipment in the compressed air energy storage system based on the design parameters of the compressed air energy storage system and the principles of engineering thermodynamics and heat transfer;

[0023] System model building module: used to connect the interfaces between the simulation models of various devices in the compressed air energy storage system, establish an integrated model of the compressed air energy storage system, and establish a thermodynamic model of the compressed air energy storage system using the variable operating characteristic curves of various devices in the compressed air energy storage system;

[0024] Variable operating condition simulation module: used to conduct variable operating condition tests based on the thermodynamic model of the compressed air energy storage system, obtain the variable operating condition simulation database of the compressed air energy storage system, and obtain the system pressure-flow curve by fitting the variable operating condition simulation data;

[0025] Charging and storage capacity estimation module: It is used to integrate the pressure using the system pressure-flow curve to obtain the remaining inflation or deflation time of the compressed air energy storage system, and multiply the inflation or deflation time by the given system load power to obtain the charging or storage capacity of the compressed air energy storage system.

[0026] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for dynamically evaluating the charging and storage capacity of the compressed air energy storage system are implemented.

[0027] The present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the above-mentioned method for dynamically evaluating the charging and storage capacity of the compressed air energy storage system are implemented.

[0028] Beneficial effect: Compared with the prior art, the significant effect of the present invention is that the present invention constructs a thermodynamic model of a compressed air energy storage system, introduces the definite relationship between the inlet / outlet pressure and flow rate of the system gas storage device under a fixed load, and then calculates the remaining charging / discharging time of the system by pressure integral, thereby effectively realizing an accurate evaluation of the real-time charging and storage performance of the compressed air energy storage system, breaking through the technical bottleneck of efficient operation and optimization of the energy storage system. This application can provide instant feedback on the storage / release capacity of compressed air energy storage power stations by dynamically evaluating the integral characteristics of the storage capacity, solving the problem of difficulty in evaluating the storage capacity of the system under variable operating conditions during the operation of the compressed air energy storage system, and the difficulty of the power supply and power grid side in obtaining the storage side's absorption capacity, thereby better responding to the flexible dispatching needs of the power grid, providing more robust technical support for the construction of a new energy supply and absorption system, and effectively expanding the absorption space for renewable energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow chart of the method of the present invention.

[0030] Figure 2 It is a schematic diagram of the pressure-flow curve of the system of the present invention. DETAILED DESCRIPTION

[0031] A preferred embodiment of the present invention is further described below in conjunction with the accompanying drawings.

[0032] See also Figure 1 As shown, this embodiment provides a method for dynamically evaluating the charging and storage capacity of a compressed air energy storage system, comprising the following steps:

[0033] (1) Based on the design parameters of the compressed air energy storage system and the principles of engineering thermodynamics, the energy conservation, mass conservation, and momentum conservation equations are used to establish simulation models of the compressor, turbine, air storage device, and heat exchanger of the compressed air energy storage system. In some preferred schemes, simulation models of auxiliary equipment such as storage tanks can also be added.

[0034] Taking a typical 300MW high-temperature adiabatic compressed air energy storage system as an example, the system has three compressors, of which the first compressor is an axial compressor, and the second and third compressors are centrifugal compressors. The compressor power of the system can be calculated by the following formula:

[0035]

[0036] Where: W is the compression work (power) per unit time; m is the mass flow rate of air; R is the gas constant; T1 is the air temperature before compression; P1 and P2 are the initial pressure and final pressure respectively; η C is the isentropic efficiency of the compressor; κ is the specific heat ratio (κ=c p / c v ).

[0037] (2) Connect the interfaces between the simulation models of various devices in the compressed air energy storage system to establish an integrated model of the compressed air energy storage system. Use the variable operating characteristic curves of various devices in the compressed air energy storage system (such as the compressor efficiency characteristic curve, turbine efficiency-load curve, etc.) to establish a thermodynamic model of the compressed air energy storage system.

[0038] (3) Based on the thermodynamic model of the compressed air energy storage system, variable operating condition tests are carried out to obtain a variable operating condition simulation database of the compressed air energy storage system, and the system pressure-flow curve is obtained by fitting the variable operating condition simulation data.

[0039] In this embodiment, the variable operating condition test includes: for each device of the compressed air energy storage system, simulation experiments are performed on the inflation and deflation processes under different load conditions, and the changes in the air parameters in the air storage device over time during the inflation and deflation processes are simulated by changing the pressure at the inlet and outlet of the air storage device; based on the variable operating condition simulation database of the compressed air energy storage system obtained from the variable operating condition simulation experiment, a fitting method of spline interpolation is used to obtain the working fluid flow required to meet the load under the condition that the pressure at the inlet / outlet of the air storage device changes continuously during the inflation / deflation process, and obtain a mapping curve of the system pressure-flow.

[0040] Taking the bleed process as an example, under the premise of determining the matching relationship between the heat exchange medium flow rate and the air flow rate, the temperature at the turbine inlet can be determined, that is, the system bleed power W disch Only with air flow m air,disch The pressure p in the gas storage device cavern Relevant, namely:

[0041] W disch =f(m air,disch ,p out )

[0042] Therefore, when the unit load is determined, the air flow rate m air,dischIt can be regarded as the outlet pressure of the gas storage device p out A single-valued function, that is:

[0043] m air,disch =g disch (p out )

[0044] Taking the deflation process of the 300MW high-temperature adiabatic compressed air energy storage system mentioned above as an example, the air flow data corresponding to different salt cavern (gas storage device) pressures under different load conditions were obtained through variable operating condition tests as shown in Table 1 below.

[0045] Table 1

[0046]

[0047] Please refer to Figure 2 As shown in the figure, the pressure-flow mapping curve under different load conditions can be obtained through the spline interpolation method.

[0048] (4) Based on the gas state equation and mass conservation equation, taking the inlet and outlet pressures of the current gas storage device of the system as the reference, the pressure is integrated using the system pressure-flow curve to obtain the remaining inflation or deflation time of the compressed air energy storage system. The inflation or deflation time is multiplied by the given system load power to obtain the charging or storage capacity of the compressed air energy storage system.

[0049] Specifically, taking the deflation process as an example, the pressure change in the gas storage device is caused by the reduction of air in the gas storage device. The air mass conservation equation in the gas storage device can be obtained:

[0050] V cavern dρ cavern =m air,disch dt

[0051] Where: V cavern is the volume of the gas storage device, ρ cavern is the air density in the gas storage device, and t is the time. From the gas state equation, it can be deduced that when the volume of the gas storage device remains unchanged:

[0052] ρ cavern =ρ(p out ,T cavern )

[0053] That is, the air density ρ in the air storage device cavern Only with the pressure p in the gas storage device cavern and the temperature in the gas storage device T cavern related.

[0054] Assuming that the degassing process is an adiabatic process, according to the ideal gas state equation, we have:

[0055]

[0056] Where: T2 and T1 are the gas temperatures in the gas storage device at the end and the beginning of the deflation process, p2 and p1 are the gas pressures in the gas storage device at the end and the beginning of the deflation process, γ is the adiabatic index of the gas, and the air density in the gas storage device is ρ cavern can be simplified to:

[0057] ρ cavern =ρ(p cavern )

[0058] That is, the air density ρ in the air storage device cavern is the pressure inside the gas storage device p cavern A single-valued function.

[0059] From this we can get:

[0060]

[0061] The total deflation time of the system can be calculated using the following formula:

[0062]

[0063] By generalizing this formula, we only need to measure the outlet pressure of the gas storage device at any time during the deflation process to calculate the remaining deflation time:

[0064]

[0065] Where: t disch is the deflation time, p cavern is the pressure of the gas storage device, p cavern,now is the current outlet pressure of the gas storage device, p cavern,min is the minimum pressure of the gas storage device, p cavern,max is the maximum pressure of the gas storage device, V cavern is the volume of the gas storage device, ρ max is the maximum value of the air density in the air storage device, ρ min is the minimum value of the air density in the air storage device, ρ′(p cavern ) is the first derivative of the relationship between air density and air storage device pressure, g disch (p cavern ) is the function of the relationship between the air flow rate and the pressure of the air storage device during the deflation process.

[0066] The obtained deflation time can be combined with the current load instruction to calculate the system's remaining energy release capacity Q disch :

[0067] Q disch =W disch t disch

[0068] Here, the current load W disch It changes in real time according to the demand of the power grid. Under different loads, the efficiency of each device in the system changes significantly. Therefore, the remaining deflation time and remaining energy release capacity calculated under different load instructions are also different.

[0069] For the inflation process, it is calculated based on the same idea as the above-mentioned deflation process, that is, the remaining inflation time is calculated by combining the air density in the air storage device through the pressure, and the remaining energy storage capacity of the system is calculated in combination with the current load. The derivation process will not be repeated here.

[0070] The calculation formula for inflation time is:

[0071]

[0072] Where: t ch is the inflation time, p cavern is the pressure of the gas storage device, p cavern,now is the current outlet pressure of the gas storage device, p cavern,max is the maximum pressure of the gas storage device, V cavern is the volume of the gas storage device, ρ max is the maximum value of the air density in the air storage device, ρ min is the minimum value of the air density in the air storage device, ρ′(p cavern ) is the first derivative of the relationship between air density and air storage device pressure, g ch (p cavern ) is the function of the relationship between the air flow rate and the pressure of the air storage device during the inflation process.

[0073] It is worth noting that the pressure-flow mapping relationship between the inflation process and the deflation process, that is, m air,disch =g(p out ) are different and cannot be calculated using the same function, so they need to be fitted separately.

[0074] Combine the obtained inflation time with the current input W ch The remaining energy storage capacity Q of the system can be calculated ch :

[0075] Q ch =W ch t ch

[0076] The embodiment of the present invention further provides a system for dynamically evaluating the storage capacity of a compressed air energy storage system, comprising:

[0077] Equipment model building module: used to build simulation models of various equipment in the compressed air energy storage system based on the design parameters of the compressed air energy storage system and the principles of engineering thermodynamics and heat transfer;

[0078] System model building module: used to connect the interfaces between the simulation models of various devices in the compressed air energy storage system, establish an integrated model of the compressed air energy storage system, and establish a thermodynamic model of the compressed air energy storage system using the variable operating characteristic curves of various devices in the compressed air energy storage system;

[0079] Variable operating condition simulation module: used to conduct variable operating condition tests based on the thermodynamic model of the compressed air energy storage system, obtain the variable operating condition simulation database of the compressed air energy storage system, and obtain the system pressure-flow curve by fitting the variable operating condition simulation data;

[0080] Charging and storage capacity estimation module: It is used to integrate the pressure using the system pressure-flow curve to obtain the remaining inflation or deflation time of the compressed air energy storage system, and multiply the inflation or deflation time by the given system load power to obtain the charging or storage capacity of the compressed air energy storage system.

[0081] An embodiment of the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method for dynamically evaluating the charging and storage capacity of the compressed air energy storage system are implemented.

[0082] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned method for dynamically evaluating the charging and storage capacity of a compressed air energy storage system.

Claims

1. A method for dynamically evaluating the storage capacity of a compressed air energy storage system, characterized in that: The following steps are involved: (1) Based on the design parameters of the compressed air energy storage system and the principles of engineering thermodynamics and heat transfer, a simulation model of each device of the compressed air energy storage system is established; (2) Connect the interfaces between the simulation models of various devices in the compressed air energy storage system, establish an integrated model of the compressed air energy storage system, and use the variable operating characteristic curves of various devices in the compressed air energy storage system to establish a thermodynamic model of the compressed air energy storage system; (3) Conduct variable operating condition tests based on the thermodynamic model of the compressed air energy storage system to obtain a variable operating condition simulation database for the compressed air energy storage system, and use the variable operating condition simulation data to fit the system pressure-flow curve; (4) The pressure is integrated using the system pressure-flow curve to obtain the remaining inflation or deflation time of the compressed air energy storage system. The inflation or deflation time is multiplied by the given system load power to obtain the charging or storage capacity of the compressed air energy storage system.

2. The method for dynamic evaluation of storage capacity according to claim 1, characterized in that: In step (1), the equipment of the compressed air energy storage system includes: a compressor, a turbine, an air storage device, and a heat exchanger.

3. The method for dynamic evaluation of storage capacity according to claim 2, characterized in that: In step (3), the variable operating condition test includes: for each device of the compressed air energy storage system, simulation experiments are performed on the inflation and deflation processes under different load conditions, and the changes in the air parameters in the air storage device over time during the inflation and deflation processes are simulated by changing the pressure at the inlet and outlet of the air storage device.

4. The method for dynamic evaluation of storage capacity according to claim 1, characterized in that: In the step (3), the spline interpolation method is used to fit the variable operating condition simulation data to obtain the system pressure-flow curve.

5. The method for dynamic evaluation of storage capacity according to claim 2, characterized in that: In the step (4), based on the gas state equation and the mass conservation equation, the pressure is integrated using the system pressure-flow curve, taking the inlet and outlet pressures of the current gas storage device of the system as a reference.

6. The method for dynamic evaluation of storage capacity according to claim 2, characterized in that: In the step (4), the calculation formula for the deflation time is: Where: t disch is the deflation time, p cavern is the pressure of the gas storage device, p cavern,now is the current outlet pressure of the gas storage device, p cavern,min is the minimum pressure of the gas storage device, V cavern is the volume of the gas storage device, ρ max is the maximum value of the air density in the air storage device, ρ min is the minimum value of the air density in the air storage device, ρ′(p cavern ) is the first derivative of the relationship between air density and air storage device pressure, g disch (p cavern ) is the function of the relationship between air flow and the pressure of the air storage device.

7. The method for dynamic evaluation of storage capacity according to claim 2, characterized in that: In step (4), the calculation formula for the inflation time is: Where: t ch is the inflation time, p cavern is the pressure of the gas storage device, p cavern,now is the current outlet pressure of the gas storage device, p cavern,max is the maximum pressure of the gas storage device, V cavern is the volume of the gas storage device, ρ max is the maximum value of the air density in the air storage device, ρ min is the minimum value of the air density in the air storage device, ρ′(p cavern ) is the first derivative of the relationship between air density and pressure of the gas storage device, g ch (p cavern ) is the function of the relationship between air flow and the pressure of the air storage device.

8. A dynamic evaluation system for the storage capacity of a compressed air energy storage system, characterized in that: include: Equipment model building module: used to build simulation models of various equipment in the compressed air energy storage system based on the design parameters of the compressed air energy storage system and the principles of engineering thermodynamics and heat transfer; System model building module: used to connect the interfaces between the simulation models of various devices in the compressed air energy storage system, establish an integrated model of the compressed air energy storage system, and establish a thermodynamic model of the compressed air energy storage system using the variable operating characteristic curves of various devices in the compressed air energy storage system; Variable operating condition simulation module: used to conduct variable operating condition tests based on the thermodynamic model of the compressed air energy storage system, obtain the variable operating condition simulation database of the compressed air energy storage system, and obtain the system pressure-flow curve by fitting the variable operating condition simulation data; Charging and storage capacity estimation module: It is used to integrate the pressure using the system pressure-flow curve to obtain the remaining inflation or deflation time of the compressed air energy storage system, and multiply the inflation or deflation time by the given system load power to obtain the charging or storage capacity of the compressed air energy storage system.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

Images