CN-122021382-A - Constant-power isothermal process modeling and simulation method for energy storage container in pressure building and energy storage stage

Abstract

The invention provides a modeling and simulation method for a constant-power isothermal process in a pressure building and energy storage stage of an energy storage container, which comprises the steps of firstly building a dynamic mathematical model of an energy storage process of a hydraulic compressed air system, and dividing the initial pressure building and energy storage stage into four sub-steps for cyclic execution: liquid is alternately filled into the two acting containers through the pump, so that gas enters the energy storage container after being compressed, and liquid backflow is completed. Modeling is based on six hypothetical conditions, including isothermal processes, ideal gas state equations, etc., and derives pressure as a function of gas volume over time. The dynamic curve of pressure change with time can be obtained through simulation calculation. The method can accurately describe the dynamic characteristics of each physical quantity in the energy storage process, provides theoretical basis for system working condition analysis, parameter matching and optimal design, simplifies complex coupling factors, and establishes a mathematical model of maximum energy storage capacity under ideal conditions.

Inventors

• KOU PANGAO
• LIANG FENGMING
• YAO MINGYU
• LIU WEIJUN
• HAN WEI
• HUANG XIAOJUN
• SONG XIAOHUI
• YANG RUI
• ZHAO HANCHEN

Assignees

• 华能陕西吴起发电有限公司
• 西安热工研究院有限公司
• 华能陕西发电有限公司

Dates

Publication Date

20260512

Application Date

20251217

Claims (7)

1. 1. The modeling and simulation method for the constant-power isothermal process in the energy storage container pressure building and energy storage stage is characterized by comprising the following steps of: Step S1, establishing a dynamic mathematical model of an energy storage process of a hydraulic compressed air system according to a pressure process assumption in a container; Step S2, the initial pressure building and energy storage stage is divided into four substeps, wherein the substep 1 fills liquid into the working container 1 by using a pump until the air pressure reaches the same pressure as the energy storage container, the substep 2 fills liquid into the working container 2 until the air pressure reaches the same pressure as the energy storage container after the pressurized gas in the working container 1 is displaced by the liquid in the pump, the substep 4 fills the pressurized gas in the working container 2 into the energy storage container after the pressurized gas in the pump is displaced by the liquid in the pump, the liquid in the working container 1 returns to the reservoir under the atmospheric pressure environment in the substep 3 and the substep 4, and the inflation is completed for 1 time; The step S3 is that in the modeling process, the assumption is adopted that (1) the energy loss of an electromechanical system is ignored, the change rate of the compression power of gas in a working container in the compression process is equal to the external electric power, the assumption is that (2) the ambient temperature is kept unchanged, the assumption is that (3) the energy storage container and the air in the working container in the energy storage process meet the isothermal process, the assumption is that (4) the energy supply of liquid in the working container flowing back to the outside of a reservoir under the atmospheric pressure is ignored, the assumption is that (5) the gas in the container meets an ideal gas state equation, the assumption is that (6) the working container is filled with the liquid and then the gas is exhausted into the energy storage container without energy loss, and the liquid in the working container does not influence the next pump operation; Step S4, combining the steps S2 and S3, and deducing a function of pressure change with time and a function of gas volume change with time according to an initial pressure building and energy storage stage based on a thermodynamic process law; And S5, based on the mathematical model in the step S4, performing multi-working-container volume parameter combinations to perform multi-working-container volume parameter combinations to obtain a pressure-time dynamic characteristic curve, analyzing the influence rule of container volume ratio on the evolution and volume change characteristics of the energy storage pressure of the system, and simultaneously researching the regulation and control mechanism of initial pressure conditions on the change of the energy storage capacity, dynamic pressure response and gas compression volume of the system by setting different sub-step 1 termination pressures.
2. 2. The method of claim 1, wherein the initial pressure build-up and energy storage stage in step S5 substep 1 is performed with a power change rate of gas compression in the power vessel equal to the external electric power: wherein, P is the input power, P is the air pressure in the working container, For the volume of air in the working vessel, the negative sign indicates that the volume is gradually decreasing.
3. 3. The method of claim 2, wherein the initial pressure build-up and energy storage stage in step S5 substep 1 is performed with a change in volume of gas in the power vessel satisfying the following equation; Wherein, P is the input power, In order to produce the air volume in the working vessel at the initial moment, Indicating the air pressure in the power vessel at the initial moment.
4. 4. A method according to claim 3, wherein the initial pressure build-up and energy storage stage in step S5 substep 1 is such that the change in gas pressure in the power vessel satisfies the following equation; Wherein, P is the input power, In order to produce the air volume in the working vessel at the initial moment, Indicating the air pressure in the power vessel at the initial moment.
5. 5. The method according to claim 4, wherein the initial pressure build-up and energy storage stage in step S5 substep 2 is performed with a power vessel, the change in volume of the gas in the energy storage vessel satisfying the following equation; Wherein, P is the input power, The sum of the volume of the working container and the volume of the energy storage container at the end of the substep 1, Indicating the air pressure in the working vessel at the end of substep 1.
6. 6. The method of claim 5, wherein the initial pressure build-up and energy storage stage in step S5 substep 2 is performed with a change in gas pressure in the working vessel satisfying the following equation; Wherein, P is the input power, The sum of the volume of the working container and the volume of the energy storage container at the end of the substep 1, Indicating the air pressure in the working vessel at the end of substep 1.
7. 7. The method according to any one of claims 1 to 6, wherein the volume of gas in the working container and the pressure equation in the substep 3 are consistent with the process in the substep 1, the volume of gas in the working container and the pressure equation in the substep 4 are consistent with the process in the substep 2, and the result of the simulation calculation includes a curve of the pressure in the energy storage container and the pressure in the working container over time during the energy storage process, and a curve of the volume in the energy storage container and the volume in the working container over time.

Description

Constant-power isothermal process modeling and simulation method for energy storage container in pressure building and energy storage stage Technical Field The embodiment of the invention relates to the technical field of hydraulic compression energy storage, in particular to a constant-power isothermal process modeling and simulation method in a pressure building and energy storage stage of an energy storage container. Background With the increasing global demand for clean energy, energy storage technology has received great attention as a key means to solve the problems of renewable energy intermittence and volatility. The hydraulic compressed air energy storage technology is used as a novel large-scale energy storage technology, has the advantages of large energy storage capacity, low cost, long service life and the like, and is considered as one of energy storage modes with great development potential. In a hydraulic compressed air energy storage system, the matching combination and the optimal design of parameters such as unit parameters, container parameters, power generation time length and the like are one of the cores of the system design, and the energy storage efficiency and the system economy of the whole system are directly affected. However, current research in this area faces many challenges. The energy storage system has strong coupling characteristics among multiple physical fields such as water, gas, machinery, electricity, heat and the like, and the wall of the container tank can exchange heat with the external environment, so that the time-varying nonlinearity of the system is enhanced. The traditional model is too insufficient in consideration factors, so that the accuracy and reliability of the model are low, meanwhile, the consideration of the model is extremely complex, the influence relation among different parameters is difficult to reveal, and the model is not suitable for the requirement of rapid system model selection design. On the other hand, most of the existing researches focus on analysis under steady-state working conditions, and simulation and prediction capabilities of ideal dynamic processes are insufficient. For example, in practical engineering applications, when isothermal compression is ideal, it is difficult to give an analytical function expression from the theoretical variation curve trend of the pressure in the energy storage container, how the actual pressure variation is optimized, and it is difficult to give an improvement direction and a solution with decision-making property in the prior art. In summary, the prior art has shortcomings in the aspects of model establishment and dynamic response characteristic analysis of the hydraulic compressed air energy storage and gas storage device, and is difficult to meet the requirements of rapid model selection design and efficient stable operation prediction of a system in actual engineering, and a model establishment and simulation method capable of highlighting main contradictions in system operation and predicting and analyzing dynamic characteristics in combination with a system operation mode is urgently needed. Disclosure of Invention The embodiment of the invention aims at solving at least one of the technical problems in the prior art and provides a modeling and simulation method for a constant-power isothermal process in a pressure building and energy storage stage of an energy storage container. A constant-power isothermal process modeling and simulation method for an energy storage container in a pressure building and energy storage stage comprises the following steps: Step S1, establishing a dynamic mathematical model of an energy storage process of a hydraulic compressed air system according to a pressure process assumption in a container; Step S2, the initial pressure building and energy storage stage is divided into four substeps, wherein the substep 1 fills liquid into the working container 1 by using a pump until the air pressure reaches the same pressure as the energy storage container, the substep 2 fills liquid into the working container 2 until the air pressure reaches the same pressure as the energy storage container after the pressurized gas in the working container 1 is displaced by the liquid in the pump, the substep 4 fills the pressurized gas in the working container 2 into the energy storage container after the pressurized gas in the pump is displaced by the liquid in the pump, the liquid in the working container 1 returns to the reservoir under the atmospheric pressure environment in the substep 3 and the substep 4, and the inflation is completed for 1 time; The step S3 is that in the modeling process, the assumption is adopted that (1) the energy loss of an electromechanical system is ignored, the change rate of the compression power of gas in a working container in the compression process is equal to the external electric power, the assumption is that (2) the ambient temperature is kep