CN-122021383-A - Constant-power variable process modeling and simulation method for energy storage container in pressure building and energy storage stage

Abstract

The invention provides a fixed-power variable process modeling and simulation method for an energy storage stage of an energy storage container, which comprises the following steps of S1, establishing a mathematical model of an energy storage process of a hydraulic compressed air system based on a pressure-time relation, S2, dividing an initial pressure establishment stage and an energy storage stage into four sub-steps, pumping liquid into two working containers alternately, extruding gas into the energy storage containers, and circularly operating until the pressure reaches a set value, S3, introducing six hypothesis simplified models including an isothermal process, an ideal gas state equation, neglecting energy loss and the like, S4, deriving a function of pressure and gas volume change along with time by combining a thermodynamic law, and S5, obtaining a pressure-time curve through simulation calculation. The method can dynamically describe the change relation of each physical quantity in the energy storage process, provides theoretical basis for system working condition analysis, parameter matching and optimization design, simplifies complex coupling factors, and establishes a maximum energy storage capacity model under ideal conditions.

Inventors

• KOU PANGAO
• LIU QI
• HAN WEI
• HUANG XIAOJUN
• YANG RUI
• ZHAO HANCHEN
• YAO MINGYU
• WU YONGHUA
• LIANG FENGMING

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 variable process in the energy storage container pressure building and energy storage stage is characterized by comprising the following steps of: step S1, establishing a mathematical model in a container in the energy storage process of a hydraulic compressed air system according to the pressure-time change relation in the 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-station simulation by setting different polytropic indexes and constant power parameter combinations to obtain a pressure-time dynamic characteristic curve so as to analyze the coupling action mechanism of thermodynamic process and power input conditions on the capacity, transient pressure evolution and gas compression volume change of the energy storage system.
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, the 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, In order to input the electric power, Representing the polytropic index, The time is represented by the time period of the day, Representing the polytropic exponent (n.noteq.1).
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, the 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, In order to input the electric power, Representing the polytropic exponent (n noteq1), Time is indicated.
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, the The sum of the volume of the working container and the volume of the energy storage container at the end of the substep 2, Indicating the air pressure in the working container at the end of substep 2, In order to input the electric power, Representing the polytropic index, Time is indicated.
6. 6. The method of claim 6, 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, the The sum of the volume of the working container and the volume of the energy storage container at the end of the substep 2, Indicating the air pressure in the working container at the end of substep 2, In order to input the electric power, Representing the polytropic exponent (n noteq1), Time is indicated.
7. 7. The method according to any one of claims 1 to 6, wherein the gas equation in the working vessel in sub-step 3 is consistent with the control volume equation in sub-step 1, the gas equation in the working vessel in sub-step 4 is consistent with the control volume equation in sub-step 2, the gas equation in the energy storage vessel is consistent with the control volume equation in sub-step 2, and the results of the simulation calculation include curves of the pressure in the energy storage vessel and the pressure in the working vessel over time during the energy storage process.

Description

Constant-power variable 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 variable process modeling and simulation method in an energy storage container compression energy storage stage. 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 variable process in a pressure-building energy-storage stage of an energy storage container. The embodiment of the invention provides a modeling and simulation method for a constant-power and variable-change process in a pressure-building energy-storage stage of an energy storage container, which comprises the following steps: step S1, establishing a mathematical model in a container in the energy storage process of a hydraulic compressed air system according to the pressure-time change relation in the 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 assump