An insulating oil thermal aging gas production mechanism analysis method and device, and a computer readable storage medium

Abstract

The application discloses an insulating oil thermal aging gas production mechanism analysis method and device and a computer readable storage medium, and belongs to the technical field of high-voltage sleeve operation state diagnosis, wherein the method comprises the following steps: constructing an insulating oil molecular dynamics simulation model and the like. Based on the computational chemistry simulation technical means, the free radical intermediates of the insulating oil thermal decomposition gas production are identified at a high temperature, the reaction free energy and enthalpy value in a wide temperature range are calculated, the low-temperature reaction spontaneity is verified, the free radical intermediates are introduced for simulation at a low temperature close to the actual aging temperature, the insulating oil thermal aging gas production mechanism is verified and obtained, the efficiency of the high-temperature simulation is utilized, the rationality and accuracy of the mechanism under the real working condition are ensured through calculation and low-temperature simulation, the alkyl benzene insulating oil thermal aging gas production mechanism is mastered from the atomic level, and theoretical and technical support is provided for high-voltage insulating sleeve aging state evaluation, and the application prospect is wide.

Description

Technical Field

[0001] This application belongs to the field of high-voltage bushing operation status diagnosis technology, specifically relating to a method and device for analyzing the gas generation mechanism of insulating oil thermal aging, and a computer-readable storage medium. Background Technology

[0002] Ultra-high voltage (UHV) AC oil-impregnated paper bushings are key equipment in UHV transmission lines, bearing the important responsibility of connecting transformers and other power equipment to the external power grid. Among various insulating oils, dodecylbenzene insulating oil is widely used in such equipment due to its advantages such as low viscosity, high electrical strength, excellent gas release properties, and low pour point. Furthermore, dodecylbenzene is biodegradable and non-toxic, making it an environmentally friendly insulating oil.

[0003] Currently, some UHV AC oil-impregnated paper bushings using dodecylbenzene as the insulating oil have experienced abnormal dissolved gas conditions during operation. Specifically, the dissolved ethane content in the oil is significantly higher than in equipment using other types of insulating oil. During long-term operation, the insulating oil gradually undergoes thermal aging and decomposition, generating small-molecule gases that dissolve in the oil. Under the influence of an electric field, these dissolved gases may precipitate and form bubbles, potentially inducing insulation failures. Therefore, a thorough investigation at the atomic level into the thermal aging gas generation mechanism of alkylbenzene insulating oil is crucial for ensuring the safe and stable operation of this type of bushing. Summary of the Invention

[0004] This application aims to at least partially address one of the technical problems in related technologies. Therefore, the purpose of this application is to propose a method and apparatus for analyzing the gas generation mechanism of insulating oil during thermal aging, as well as a computer-readable storage medium. Based on computational chemical simulation technology, this application identifies free radical intermediates generated by the thermal decomposition of insulating oil at higher temperatures, verifies the spontaneity of low-temperature reactions by calculating the reaction free energy and enthalpy over a wide temperature range, and finally introduces free radical intermediates at a lower, near-actual aging temperature for simulation, verifying and obtaining the gas generation mechanism of insulating oil during thermal aging. This approach utilizes the efficiency of high-temperature simulation while ensuring the rationality and accuracy of the mechanism under real-world conditions through calculation and low-temperature simulation. It provides a theoretical and technical support for assessing the aging status of high-voltage insulating bushings by understanding the gas generation mechanism of alkylbenzene insulating oil at the atomic level, and has broad application prospects.

[0005] The first aspect of this application proposes a method for analyzing the gas generation mechanism of insulating oil during thermal aging. According to an embodiment of this application, the method includes the following steps: Constructing a molecular dynamics simulation model for insulating oil; In the molecular dynamics simulation model of insulating oil, reaction molecular dynamics is used to simulate the pyrolysis process of insulating oil and to analyze the free radical intermediates generated by the thermal decomposition gas of insulating oil. Density functional theory was used to analyze the chemical process of the free radical intermediate and to deduce the generation mechanism of the insulating oil thermal aging gas. Under the condition of adding the free radical intermediate, the reaction molecular dynamics simulation of the gas generation process of insulating oil during thermal aging was carried out to verify the gas generation mechanism of insulating oil during thermal aging. The reaction molecular dynamics simulation temperature T1 when the pyrolysis process of insulating oil is simulated using reaction molecular dynamics in the insulating oil molecular dynamics simulation model and the reaction molecular dynamics simulation temperature T2 when the thermal aging gas generation process of insulating oil is simulated using reaction molecular dynamics under the condition of additional addition of the free radical intermediate satisfy the following relationship: T1 > T2.

[0006] The gas generation mechanism analysis method for thermal aging of insulating oil described in the above embodiments of this application is based on computational chemistry simulation technology. It identifies free radical intermediates generated by the thermal decomposition of insulating oil at higher temperatures, verifies the spontaneity of low-temperature reactions by calculating the reaction free energy and enthalpy over a wide temperature range, and finally introduces free radical intermediates at a lower temperature close to the actual aging temperature for simulation to verify and obtain the gas generation mechanism of insulating oil thermal aging. This method utilizes the efficiency of high-temperature simulation while ensuring the rationality and accuracy of the mechanism under real working conditions through calculation and low-temperature simulation. It provides a theoretical and technical support for the assessment of the aging status of high-voltage insulating bushings by understanding the gas generation mechanism of alkylbenzene insulating oil at the atomic level, and has broad application prospects.

[0007] In addition, the method for analyzing the gas generation mechanism of insulating oil during thermal aging according to the above embodiments of this application may also have the following additional technical features: In some embodiments of this application, the insulating oil comprises dodecylbenzene insulating oil.

[0008] In some embodiments of this application, the steps for constructing a molecular dynamics simulation model of insulating oil include the following processes: A molecular dynamics simulation model of a linear dodecylbenzene monomer was constructed using molecular simulation software. Based on the molecular dynamics simulation model of the linear dodecylbenzene monomer, a molecular model of the dodecylbenzene insulating oil system was constructed and subjected to geometric optimization, annealing cycle, and kinetic equilibrium treatment to obtain the molecular dynamics simulation model of the insulating oil.

[0009] In some embodiments of this application, the molecular dynamics simulation model of the linear dodecylbenzene monomer includes: a plurality of unit cells of the linear dodecylbenzene monomer, wherein the unit cells include cubic unit cells with a side length of 33-34 angstroms; And / or, the steps of constructing a molecular model of the dodecylbenzene insulating oil system based on the molecular dynamics simulation model of the linear dodecylbenzene monomer and performing geometric optimization, annealing cycling, and kinetic equilibrium processing to obtain the molecular dynamics simulation model of the insulating oil include the following processes: The molecular dynamics simulation model of the linear dodecylbenzene monomer was imported into molecular dynamics simulation software. Using the CHO force field of the carbon, hydrogen, and oxygen atom system, two annealing cycles from 273 K to 573 K were performed under an isothermal and isobaric ensemble. The heating and cooling times in each cycle were 95-105 ps, and the temperature was maintained at 573 K and 273 K for 45-55 ps, respectively. The total duration of the annealing cycles was 590-610 ps. The boundary was set as a periodic boundary, and the pressure was 1 standard atmosphere. Then, relaxation was performed under a canonical ensemble at 273 K for a total duration of 390-410 ps.

[0010] In some embodiments of this application, the step of using reactive molecular dynamics to simulate the pyrolysis process of insulating oil in the insulating oil molecular dynamics simulation model and analyzing the free radical intermediates generated by the thermal decomposition gas of insulating oil includes the following steps: In the molecular dynamics simulation model of insulating oil, reactive molecular dynamics is used to simulate the pyrolysis process of insulating oil. The types of gases produced by the thermal decomposition of insulating oil at temperatures of 1800~2600K are analyzed to obtain the characteristic gases of thermal decomposition of insulating oil. The types and quantities of free radical intermediates produced by the characteristic gases of thermal decomposition of insulating oil are identified and tracked.

[0011] In some embodiments of this application, the characteristic gases of thermal decomposition of the insulating oil include H2, CH4, C2H6, C2H4, and C2H2; And / or, the free radical intermediate of the C2H6 includes C2H5·.

[0012] In some embodiments of this application, the steps for analyzing the chemical process of the free radical intermediate generation using density functional theory and speculating on the generation mechanism of the insulating oil thermal aging gas include the following: Density functional theory was used in quantum chemistry software to simulate and analyze the free radical intermediate. The reaction free energy and enthalpy of different reaction pathways that generate the free radical intermediate and the characteristic gas of thermal decomposition of insulating oil were calculated in a wide temperature range. The spontaneity and exothermic characteristics of different reaction pathways in the low temperature region were verified. The kinetic and thermodynamic competition relationship of different generation pathways was compared. Based on the experimental and simulation calculation results, the generation mechanism of the thermal aging gas of insulating oil was inferred. And / or, under the condition of additional addition of the free radical intermediate, the steps of performing reaction molecular dynamics simulation of the gas generation process of insulating oil during thermal aging to verify the gas generation mechanism of insulating oil during thermal aging include the following processes: Four to seven free radical intermediates were added to the molecular dynamics simulation model of the insulating oil. The pyrolysis process of the insulating oil was simulated using molecular simulation software. The process of generating gas during thermal aging of the insulating oil at a temperature of 1400 to 1600 K was analyzed. The frequency of the generation of characteristic gases of thermal decomposition of the insulating oil by the reaction of the free radical intermediates was counted. The gas generation mechanism of thermal aging of insulating oil was verified and obtained.

[0013] The second aspect of this application discloses an apparatus for analyzing the gas generation mechanism of insulating oil during thermal aging. According to embodiments of this application, the apparatus, used to implement the method described in the first aspect, includes: The model building module is used to build molecular dynamics simulation models of insulating oil; The pyrolysis simulation module is used to simulate the pyrolysis process of insulating oil using reaction molecular dynamics in the insulating oil molecular dynamics simulation model, and to analyze the free radical intermediates generated by the thermal decomposition gas of insulating oil. The mechanism prediction module uses density functional theory to analyze the chemical process of the free radical intermediate and predicts the generation mechanism of the insulating oil thermal aging gas. Mechanism verification module: used to perform reaction molecular dynamics simulation of the gas generation process of insulating oil during thermal aging under the condition of additional addition of the free radical intermediate, and to verify the gas generation mechanism of insulating oil during thermal aging; Specifically, the reaction molecular dynamics simulation temperature T1 when simulating the pyrolysis process of insulating oil using reaction molecular dynamics in the insulating oil molecular dynamics simulation model, and the reaction molecular dynamics simulation temperature T2 when simulating the gas generation process of insulating oil during thermal aging under the condition of additional addition of the free radical intermediate, satisfy the following relationship: T1 > T2. Thus, the gas generation mechanism of insulating oil during thermal aging is analyzed.

[0014] In addition, the insulating oil thermal aging gas generation mechanism analysis apparatus according to the above embodiments of this application may also have the following additional technical features: In some embodiments of this application, the model building module includes: Monomer building blocks are used to construct unit cells for linear dodecylbenzene monomer molecules, wherein the unit cells are cubes with a side length of 33-34 angstroms; The system optimization unit is used to perform two annealing cycles from 273K to 573K under isothermal and isobaric ensembles. The heating and cooling time for each cycle is 95~105ps, and the holding time at 573K and 273K is 45~55ps, with a total annealing time of 590~610ps. Then, it relaxes at 273K under a canonical ensemble for 390~410ps. And / or, the pyrolysis simulation module includes: Gas identification unit is used to identify characteristic gases of thermal decomposition of insulating oil, including H2, CH4, C2H6, C2H4, and C2H2. A free radical tracking unit is used to track the type and quantity of C2H5·, a free radical intermediate of C2H6; And / or, the mechanism verification module includes: Intermediate injection unit, used to add 4 to 7 free radical intermediates to the molecular dynamics simulation model of insulating oil; The reaction statistics unit is used to count the frequency of the formation of characteristic gases from thermal decomposition of free radical intermediates.

[0015] A third aspect of this application discloses a computer-readable storage medium. According to an embodiment of this application, the computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method described in the first aspect. This enables the analysis of the gas generation mechanism during the thermal aging of insulating oil.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a flowchart illustrating the method for analyzing the gas generation mechanism of insulating oil during thermal aging in this application.

[0018] Figure 2 The relevant molecular model for alkylbenzene insulating oil; Figure 2 (a) is a molecular model of straight-chain dodecylbenzene; Figure 2 (b) is a model atomic labeling diagram of dodecylbenzene; Figure 2 (c) is the dodecylbenzene oil model.

[0019] Figure 3 The curves show the changes in the characteristic gases produced during the decomposition of dodecylbenzene oil at different temperatures and the number of undecomposed dodecylbenzene molecules.

[0020] Figure 4 The value represents the carbon-hydrogen bond energy on the carbon chain of the dodecylbenzene molecule.

[0021] Figure 5 The reaction C2H5·+C at 0-3000K 18 H 30 →C2H6+C 18 H 29 ·_n's reaction free energy.

[0022] Figure 6 The free energies are the reaction free energies of the three ethane formation pathways from 0 to 3000 K.

[0023] Figure 7 The model is created by adding 5 C2H5· molecules to dodecylbenzene oil.

[0024] Figure 8 This refers to the process by which C2H5· reacts with dodecylbenzene molecules at 1600K to produce ethane molecules. Figure 8 (a) When it is 0ps; Figure 8 (b) When it is 0.110 ps; Figure 8 (c) When it is 0.113 ps; Figure 8 (d) is 0.116ps.

[0025] Figure 9 Test results to verify the accuracy of the analytical method for the gas generation mechanism of insulating oil during thermal aging provided in this application. Detailed Implementation

[0026] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0027] When analyzing the gas generation mechanism of dodecylbenzene insulating oil during thermal aging, existing technical systems, including experimental analysis methods, high-temperature reaction molecular dynamics simulations, and density functional theory calculations for small systems, all have inherent limitations, specifically: 1) Experimental analysis methods are limited by the slow reaction kinetics of the thermal aging process, resulting in extremely low intermediate concentrations and difficulty in real-time tracking of reaction pathways. This makes it difficult to directly observe key intermediates and final products (excluding characteristic gases) through experimental means, thus failing to fully reveal the microscopic processes of gas generation during thermal aging. 2) While high-temperature reaction molecular dynamics simulations can shorten simulation time by accelerating the reaction process, their reliance on significantly increased temperatures (typically 2000-3000K) to drive the reaction deviates significantly from the actual operating conditions of insulating oil, leading to distortion of the reaction pathways. This distortion manifests as abnormal changes in the thermodynamic equilibrium state and the kinetic competition relationship, failing to accurately reflect the complex network characteristics of multiple parallel reaction pathways under aging conditions. 3) Although density functional theory calculations can accurately assess the energy barrier parameters of specific reactions at the electronic level, their high computational cost severely limits the scalability of the simulation system. Current technology can only handle model systems of single or a few molecules, and cannot reflect the macroscopic statistical effects necessary for the coexistence of multiple molecules and the competition of complex reaction networks in real oil environments. It is difficult to capture the cooperative decomposition behavior and product distribution patterns of insulating oil molecule groups during thermal aging, resulting in incomplete and unreliable mechanism analysis.

[0028] The first aspect of this application proposes a method for analyzing the gas generation mechanism of insulating oil during thermal aging. According to embodiments of this application, such as... Figure 1 As shown, the method includes the following steps: Constructing a molecular dynamics simulation model for insulating oil; In the molecular dynamics simulation model of insulating oil, reaction molecular dynamics is used to simulate the pyrolysis process of insulating oil and to analyze the free radical intermediates generated by the thermal decomposition gas of insulating oil. Density functional theory was used to analyze the chemical process of the free radical intermediate and to deduce the generation mechanism of the insulating oil thermal aging gas. Under the condition of adding the free radical intermediate, the reaction molecular dynamics simulation of the gas generation process of insulating oil during thermal aging was carried out to verify the gas generation mechanism of insulating oil during thermal aging. The reaction molecular dynamics simulation temperature T1 when the pyrolysis process of insulating oil is simulated using reaction molecular dynamics in the insulating oil molecular dynamics simulation model and the reaction molecular dynamics simulation temperature T2 when the thermal aging gas generation process of insulating oil is simulated using reaction molecular dynamics under the condition of additional addition of the free radical intermediate satisfy the following relationship: T1 > T2.

[0029] The gas generation mechanism analysis method for insulating oil thermal aging described in the above embodiments of this application is based on computational chemistry simulation technology. It identifies free radical intermediates generated by the thermal decomposition of insulating oil at higher temperatures, verifies the spontaneity of the low-temperature reaction by calculating the reaction free energy and enthalpy over a wide temperature range, and finally introduces free radical intermediates at a lower, near-actual aging temperature for simulation. This verifies and obtains the gas generation mechanism of insulating oil thermal aging. Thus, it utilizes the efficiency of high-temperature simulation while ensuring the rationality and accuracy of the mechanism under real-world conditions through calculation and low-temperature simulation. It provides a theoretical and technical support for assessing the aging status of high-voltage insulating bushings by understanding the gas generation mechanism of alkylbenzene insulating oil at the atomic level, and has broad application prospects. Specifically: This application combines molecular dynamics and computational chemistry simulation techniques, employing a coupled strategy of "high-temperature reaction molecular dynamics simulation - density functional theory thermodynamics and kinetic calculations - low-temperature reaction molecular dynamics simulation verification." First, it models and calculates the key free radical intermediates in the thermal aging gas generation process of alkylbenzene insulating oil using reaction molecular dynamics. Then, it uses density functional theory to simulate and analyze the chemical process of generating these free radical intermediates (including simulating and analyzing the free energy and enthalpy of different reaction pathways over a wide temperature range, and analyzing the thermodynamic spontaneity and kinetic competition of free radical reactions), thus inferring the generation mechanism of the insulating oil's thermal aging gas. Finally, at a lower temperature and closer to the actual aging temperature, it simulates the characteristic gas generation process involving key free radicals using reaction molecular dynamics, statistically analyzing reaction frequencies to verify and determine the gas generation mechanism of insulating oil during thermal aging. This effectively overcomes the limitations of existing single-method approaches in terms of temperature extrapolation, system scale, and computational cost.

[0030] According to some specific embodiments of this application, the method for analyzing the gas generation mechanism of insulating oil thermal aging according to the above embodiments of this application may also have the following additional technical features: According to some embodiments of this application, the insulating oil includes dodecylbenzene insulating oil, which (abbreviated as DDB) is made of dodecylbenzene (chemical formula C). 18 H 30 The core component of the synthetic insulating medium is a mixture of aromatic hydrocarbons composed of alkyl side chains (containing 9-15 carbon atoms) and benzene rings. Commercially available products can be purchased directly for testing.

[0031] According to some specific embodiments of this application, the steps for constructing a molecular dynamics simulation model of insulating oil include the following: constructing a molecular dynamics simulation model of a linear dodecylbenzene monomer using molecular simulation software; constructing a molecular model of the dodecylbenzene insulating oil system based on the linear dodecylbenzene monomer molecular dynamics simulation model and performing geometric optimization, annealing cycling, and kinetic equilibrium processing to obtain the molecular dynamics simulation model of the insulating oil. Thus, this application constructs a system model containing multiple dodecylbenzene molecules, obtaining a multi-molecular system model that closely approximates the density of real oil products, ensuring that the model closely approximates the physical state of real oil products at the atomic level, and providing a reasonable initial structure for subsequent reaction simulations.

[0032] According to some specific embodiments of this application, the linear dodecylbenzene monomer molecular dynamics simulation model includes: a plurality of unit cells of the linear dodecylbenzene monomer, wherein the unit cell includes a cubic unit cell with a side length of 33~34 Å (e.g., 33.3 Å, etc.) and may contain, for example, 80 dodecylbenzene molecules; and / or, the step of constructing a molecular model of the dodecylbenzene insulating oil system based on the linear dodecylbenzene monomer molecular dynamics simulation model and performing geometric optimization, annealing cycle and kinetic equilibrium processing to obtain the insulating oil molecular dynamics simulation model includes the following process: exporting the linear dodecylbenzene monomer molecular dynamics simulation model to... In molecular dynamics simulation software, using the CHO force field of a carbon, hydrogen, and oxygen atom system, two annealing cycles from 273 K to 573 K are performed under an isothermal and isobaric ensemble. The heating and cooling times within each cycle are 95–105 ps (e.g., 100 ps), and the temperature is maintained at 573 K and 273 K for 45–55 ps (e.g., 50 ps), respectively. The total annealing cycle time is 590–610 ps (e.g., 600 ps). The boundary is set as a periodic boundary, and the pressure is 1 standard atmosphere. Then, relaxation is performed under a canonical ensemble at 273 K for a total time of 390–410 ps (e.g., 400 ps). Thus, the constructed molecular dynamics simulation model of insulating oil closely approximates the physical state of real oil at the atomic level.

[0033] In some embodiments of this application, the step of using reactive molecular dynamics to simulate the pyrolysis process of insulating oil in the insulating oil molecular dynamics simulation model and analyzing the free radical intermediates generated by the thermal decomposition gases of insulating oil includes the following process: simulating the pyrolysis process of insulating oil using reactive molecular dynamics in the insulating oil molecular dynamics simulation model, analyzing the types of gases generated by the thermal decomposition of insulating oil at temperatures of 1800~2600K (e.g., 1800K, 2200K, 2600K, etc.), obtaining characteristic gases of insulating oil thermal decomposition; identifying and tracking the types and quantities of free radical intermediates generated by the characteristic gases of insulating oil thermal decomposition. This application uses reactive molecular dynamics to simulate the decomposition process of alkylbenzene insulating oil at high temperatures, statistically analyzes the types of characteristic gases generated by decomposition, tracks the types and quantities of free radicals generated during the decomposition of dodecylbenzene insulating oil, extracts the types and concentrations of free radicals in real time, and identifies the key free radical intermediates generated.

[0034] According to some specific embodiments of this application, the characteristic gases of the thermal decomposition of the insulating oil include H2, CH4, C2H6, C2H4, and C2H2. During the detection and analysis process, this application confirmed that the characteristic gases generated by dodecylbenzene at high temperatures are mainly H2, CH4, C2H6, C2H4, and C2H2.

[0035] According to some specific embodiments of this application, the free radical intermediate of C2H6 includes C2H5·. Since the gas produced by the dodecylbenzene oil-impregnated paper sleeve during operation is mainly ethane, this application analyzed the generation pathway of the characteristic gas and found that the generation of ethane is closely related to the C2H5· free radical and the highly reactive H· free radical in the system.

[0036] According to some specific embodiments of this application, the steps of using density functional theory to analyze the chemical process of free radical intermediate generation and to infer the generation mechanism of insulating oil thermal aging gas include the following: using density functional theory in quantum chemistry software to simulate and analyze the free radical intermediate, calculating the reaction free energy and enthalpy of different reaction pathways that generate the free radical intermediate and the characteristic gas of insulating oil thermal decomposition under a wide temperature range, verifying the spontaneity and exothermic characteristics of different reaction pathways in the low-temperature region, comparing the kinetic and thermodynamic competition relationships of different generation pathways, and inferring the generation mechanism of insulating oil thermal aging gas based on experimental and simulation calculation results. This application uses density functional theory to simulate and analyze the chemical process of free radical generation: for the identified key free radical reaction pathways, DFT (Discrete Fourier Transform) method is used for geometric optimization, frequency analysis, and thermodynamic calculations to obtain the reaction free energy and enthalpy under a wide temperature range, evaluate the thermodynamic spontaneity and kinetic competition relationships of each pathway, and based on thermodynamic and kinetic analysis, preliminarily infer the generation mechanism of characteristic gas.

[0037] According to some specific embodiments of this application, the steps for verifying the gas generation mechanism of insulating oil thermal aging by performing reaction molecular dynamics simulation of the insulating oil thermal aging gas generation process under the condition of additional addition of the free radical intermediate include the following: adding 4 to 7 of the free radical intermediates to the insulating oil molecular dynamics simulation model, using molecular simulation software to perform reaction molecular dynamics simulation analysis of the insulating oil thermal aging gas generation process at a temperature of 1400~1600K (e.g., 1400K, 1500K, 1600K, etc.), counting the frequency of the free radical intermediates reacting to generate the characteristic gases of the insulating oil thermal decomposition, and verifying and obtaining the gas generation mechanism of insulating oil thermal aging. For aging, the vast majority of oil molecules do not react; the area surrounding the free radical intermediates observed in this application is mainly composed of oil molecules. Therefore, by taking advantage of the short existence time and fast reaction rate of free radicals, key free radicals can be introduced into the system. At a lower temperature than when analyzing the generation of free radical intermediates from the thermal decomposition of insulating oil, molecular dynamics simulations of the reaction can be performed. The frequency of the reaction with oil molecules to generate characteristic gases can be counted, the reaction process can be directly observed, and the rationality of the mechanism can be verified.

[0038] The second aspect of this application discloses an apparatus for analyzing the gas generation mechanism of insulating oil during thermal aging. According to embodiments of this application, the apparatus, used to implement the method described in the first aspect, includes: The model building module is used to build molecular dynamics simulation models of insulating oil; The pyrolysis simulation module is used to simulate the pyrolysis process of insulating oil using reaction molecular dynamics in the insulating oil molecular dynamics simulation model, and to analyze the free radical intermediates generated by the thermal decomposition gas of insulating oil. The mechanism prediction module uses density functional theory to analyze the chemical process of the free radical intermediate and predicts the generation mechanism of the insulating oil thermal aging gas. Mechanism verification module: used to perform reaction molecular dynamics simulation of the gas generation process of insulating oil during thermal aging under the condition of additional addition of the free radical intermediate, and to verify the gas generation mechanism of insulating oil during thermal aging; Specifically, the reaction molecular dynamics simulation temperature T1 when simulating the pyrolysis process of insulating oil using reaction molecular dynamics in the insulating oil molecular dynamics simulation model, and the reaction molecular dynamics simulation temperature T2 when simulating the gas generation process of insulating oil during thermal aging under the condition of additional addition of the free radical intermediate, satisfy the following relationship: T1 > T2. Thus, the gas generation mechanism of insulating oil during thermal aging is analyzed.

[0039] According to some specific embodiments of this application, the model building module includes: Monomer building blocks are used to construct unit cells for linear dodecylbenzene monomer molecules, wherein the unit cells are cubes with a side length of 33-34 angstroms; The system optimization unit is used to perform two annealing cycles from 273K to 573K under isothermal and isobaric ensembles. The heating and cooling time for each cycle is 95~105ps, and the holding time at 573K and 273K is 45~55ps, with a total annealing time of 590~610ps. Then, it relaxes at 273K under a canonical ensemble for 390~410ps. And / or, the pyrolysis simulation module includes: Gas identification unit is used to identify characteristic gases of thermal decomposition of insulating oil, including H2, CH4, C2H6, C2H4, and C2H2. A free radical tracking unit is used to track the type and quantity of C2H5·, a free radical intermediate of C2H6; And / or, the mechanism verification module includes: Intermediate injection unit, used to add 4 to 7 free radical intermediates to the molecular dynamics simulation model of insulating oil; The reaction statistics unit is used to count the frequency of the formation of characteristic gases from thermal decomposition of free radical intermediates.

[0040] A third aspect of this application discloses a computer-readable storage medium. According to an embodiment of this application, the computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method described in the first aspect. This enables the analysis of the gas generation mechanism during the thermal aging of insulating oil.

[0041] The embodiments of this application are described in detail below. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. In addition, unless otherwise specified, all reagents used in the following embodiments are commercially available or can be synthesized according to the methods described herein or known methods. For reaction conditions not listed, they are also readily available to those skilled in the art.

[0042] Example This embodiment provides a method and apparatus for analyzing the gas generation mechanism of thermal aging of insulating oil, as well as a computer-readable storage medium. Taking dodecylbenzene insulating oil as an example, the gas generation mechanism of the main components in dodecylbenzene insulating oil during thermal aging is analyzed in detail at the atomic level, including the following four steps: Step 1: Constructing a molecular dynamics simulation model of dodecylbenzene insulating oil: Constructing a molecular dynamics simulation model of dodecylbenzene monomers, further constructing a molecular model of the dodecylbenzene insulating oil system, and performing geometric optimization, annealing cycle, and kinetic equilibrium treatment on the insulating oil system; Step 2: Reaction molecular dynamics simulation analysis of key free radicals generated by characteristic gases of dodecylbenzene insulating oil: The reaction molecular dynamics method is used to simulate the decomposition process of alkylbenzene insulating oil, statistically analyze the types of characteristic gases generated by decomposition, track the types and quantities of free radicals generated during the decomposition of dodecylbenzene insulating oil, extract the types and concentrations of free radicals in real time, and identify the key free radical intermediates generated. Step 3: Density functional theory simulation analysis of the chemical process of free radical generation: The key free radical reaction intermediates obtained in Step 2 are statistically analyzed and subjected to geometric optimization, frequency analysis and thermodynamic calculation in quantum chemistry software. The reaction free energy and reaction enthalpy of different reaction paths for generating free radicals and characteristic gases are calculated in a wide temperature range. The spontaneity and exothermic characteristics of the path in the low temperature region are verified, and the kinetic and thermodynamic competition relationship of different generation paths is compared. Step 4: Analysis of characteristic gas generation process under thermal aging temperature by reaction molecular dynamics simulation: By adding key types of free radicals to the dodecylbenzene insulating oil model, reaction molecular dynamics simulation is carried out at near-actual aging temperature. The reaction of free radicals is tracked and statistically analyzed to obtain the gas generation mechanism of dodecylbenzene insulating oil under thermal aging. Specifically, the generation mechanism of ethane, a characteristic gas of thermal aging of dodecylbenzene insulating oil, will be used as an example to explain the above analytical method in detail below: 1. Construct a molecular dynamics simulation model for dodecylbenzene insulating oil. (1) Constructing a molecular dynamics simulation model of the dodecylbenzene oil system The main component of dodecylbenzene insulating oil is linear dodecylbenzene molecules. Molecular simulation software was used to construct the linear dodecylbenzene molecule structure and perform geometric optimization. The results are as follows: Figure 2 As shown in (a), a density of 0.885 g / cm³ was constructed using the Monte Carlo method. 3 The unit cell contains several linear dodecylbenzene molecules. In this example, the unit cell constructed is a cubic unit cell with a side length of 33.3 Å, containing 80 dodecylbenzene molecules.

[0043] (2) Optimize the structure of dodecylbenzene oil The obtained model was imported into molecular dynamics simulation software, and the dodecylbenzene oil system structure was optimized through relaxation with a total duration of 1 ns. Using a CHO force field (containing the interaction of carbon, hydrogen, and oxygen atoms) with a step size of 0.1 fs, two annealing cycles from 273 K to 573 K were first performed in an Isothermal-Isobaric Ensemble (NPT) ensemble. The heating and cooling times within each cycle were 100 ps, ​​with 50 ps held at 573 K and 273 K respectively for sufficient relaxation. The total annealing cycle duration was 600 ps. Periodic boundaries were set, and the pressure was 1 standard atmosphere. The annealing cycle provided the model with a suitable density and reduced the total system energy. Then, a relaxation of 400 ps was performed in a canonical ensemble (NVT) ensemble at 273 K to further reduce the total system energy. The resulting model is shown below. Figure 2 As shown in (c).

[0044] 2. Reaction molecular dynamics simulation analysis of key free radicals generated by characteristic gases from dodecylbenzene insulating oil (1) Analyze the types of characteristic gases produced by the decomposition of alkylbenzene insulating oil. For reaction molecular dynamics, the reaction time that can be simulated is usually in the picosecond to nanosecond range, and a higher temperature needs to be set to accelerate the reaction process. Therefore, in this example, three temperatures of 1800K, 2200K and 2600K are selected for decomposition simulation, with a step size of 0.1fs, and the total decomposition time is 1500ps, 1000ps and 1000ps respectively. Figure 3The figure shows the variation curves of the characteristic gas molecules (H2, CH4, C2H6, C2H4, and C2H2) and the number of undecomposed dodecylbenzene molecules in the dodecylbenzene oil model at 1800K, 2200K, and 2600K. Due to the lower temperature at 1800K, the dodecylbenzene molecules decompose more slowly; only 15 dodecylbenzene molecules decomposed after 1500 ps of simulation. For the dodecylbenzene oil model pyrolyzed at 2200K, only 3 dodecylbenzene molecules remained undecomposed after 1000 ps of simulation. In the simulation at 2600K, all dodecylbenzene molecules completely decomposed after approximately 164 ps. The figure shows that the characteristic gases generated by dodecylbenzene at high temperatures are mainly H2, CH4, C2H6, C2H4, and C2H2.

[0045] (2) Identify and track the types and quantities of key free radicals in the process of characteristic gas generation. Since the dodecylbenzene oil-impregnated paper sleeve mainly produces ethane during operation, the example focuses on the ethane generation pathway. First, the generation path of the characteristic gas is analyzed. Because the total number of reactions occurring at 1800K is relatively small, and the decomposition rate of dodecylbenzene at 2600K is too fast to be easily captured, a model simulated at 2200K is chosen to analyze the initial decomposition location of dodecylbenzene molecules and the generation pathway of ethane molecules during the simulation.

[0046] Table 1 shows the reactions that generate C2H6 at 2200K and the number of reactions. After 1000 ps of reaction at 2200K, a total of 13 C2H6 molecules were generated. Among them, 12 C2H6 molecules were generated by C2H5· obtaining a hydrogen atom or free H· from the system or other molecules. Nine of these were generated by the combination of C2H5· and H·, three were generated by C2H5· abstracting H· from other molecules, and only one was generated by the combination of two CH3· free radicals. This indicates that the generation of ethane is closely related to C2H5· free radicals and highly reactive H· free radicals in the system.

[0047] Table 1. Reactions that produce C2H6 at 2200K and their frequency.

[0048] 3. Density functional theory simulation analysis of the chemical processes of free radical generation (1) Tracing the generation pathway of key free radicals during the decomposition of dodecylbenzene insulating oil The generation of ethane is closely related to the C2H5· and reactive H in the system. The reaction for the formation of ethyl at 2200 K is shown in Table 2. The ethyl radical is mainly generated by the decomposition of paraffinic and aromatic components produced by the decomposition of dodecylbenzene. For the system simulated for decomposition at 2200 K, the ethyl radical is mainly generated by the decomposition of C4H9· radical.

[0049] Table 2. Reactions that generate C2H5· at 2200K and their frequency.

[0050] Density functional theory was used to calculate the C-H bond energies of the dodecylbenzene molecule. Gaussian 16 was used to model the structures of interest, and geometric optimization and vibrational analysis were performed using b3lyp functionals and the 6-31G* basis set. Frequency analysis confirmed the absence of imaginary frequencies in each structure. The free energy and enthalpy of the structures at different temperatures were calculated, and further calculations were performed on the bond energies, enthalpy changes, and free energy changes of the molecules.

[0051] For the nomenclature of carbon atoms in the dodecylbenzene molecule, see [link to relevant documentation]. Figure 2 (b) Due to the high bond energy of the carbon-hydrogen bonds on the benzene ring, which are difficult to decompose, only the carbon-hydrogen bond energies on the carbon chain of the dodecylbenzene molecule were calculated. The carbon atom at the α-position next to the benzene ring of the dodecylbenzene molecule was named C1, and the carbon atom at the β-position was named C2. The carbon-hydrogen bond between C1 and the hydrogen atom attached to it was named C1-H, and so on. The results are as follows: Figure 4 As shown, simulation calculations show that the C1-H bond energy in the dodecylbenzene molecule is significantly lower than that of other C-H bonds, at 375.4 kJ / mol, which is about 40-50 kJ / mol lower than that of other C-H bonds on the carbon chain. This indicates that the C-H bonds at the benzylic position are more easily broken.

[0052] (2) Compare the kinetic and thermodynamic competition between different generation pathways of characteristic gases The above analysis suggests that C2H5· may have been converted into ethane through a reaction involving the abstraction of a hydrogen atom from the benzylic position of dodecylbenzene. The low bond energy of the benzylic CH bond is the core factor driving this hydrogen atom transfer. Therefore, the reaction free energy and enthalpy of C2H5· abstracting hydrogen atoms at different positions on the dodecylbenzene carbon chain were further calculated at different temperatures. The results are shown below. Figure 5 And Table 3, Figure 5 C 18 H 30 Represents a dodecylbenzene molecule, C 18 H 29 _n represents the molecule after the Cn-H bond of the dodecylbenzene molecule is broken, and C is used to represent the molecule. 18 H 29 _n represents the reaction C2H5·+C 18 H30 →C2H6+C 18 H 29 ·_n. The results show that C2H5· abstracts the benzyl hydrogen from the dodecylbenzene molecule to produce ethane and C 18 H 29 The reaction free energy and enthalpy of ·_1 are significantly lower than those of the reaction involving the capture of hydrogen from other sites on the carbon chain. Furthermore, the free energy of this reaction remains less than zero over a wide temperature range, indicating spontaneous occurrence and exothermic behavior. This is related to the relatively low C-H bond energy at the benzylic position of dodecylbenzene mentioned earlier. When n≥2, i.e., when C2H5· does not capture benzylic hydrogen, the activation energy of this group of reactions gradually increases with increasing temperature, becoming a non-spontaneous reaction at high temperatures.

[0053] Table 3. C2H5·+C at 298.15K 18 H 30 →C2H6+C 18 H 29 ·_n enthalpy of reaction

[0054] C2H5· is inherently unstable, making it highly susceptible to β-shear dehydrogenation to form more stable ethylene molecules and hydrogen atoms. This process was compared with the reaction of C2H5· abstracting benzyl hydrogen from dodecylbenzene molecules to produce ethane in dodecylbenzene oil, and with the reaction free energy and enthalpy of C2H5· abstracting benzyl hydrogen from dodecylbenzene molecules to produce ethylene and hydrogen. The results are as follows: Figure 6 As shown in Table 4, for ease of discussion, these three reactions are named reactions A, B, and C, respectively, corresponding to... Figure 6 The black, red, and blue lines in the diagram. The results show that, within the calculated temperature range, the enthalpy changes of the three reactions are, in descending order, ΔH. A (T)<ΔH C (T)<ΔH B (T), and the free energy changes of the three reactions at 0-1340K are ΔG respectively. A (T)<ΔG C (T)<ΔG B (T) indicates that at lower temperatures, C2H5· tends to seize the benzylic hydrogen from the dodecylbenzene molecule to form ethane rather than dehydrogenate it to form ethylene. As temperature increases, ΔG A (T), ΔG C (T) has an intersection point near 1340K, ΔG A (T), ΔG BThe intersection of (T) near 2670K indicates that at higher temperatures, C2H5· is more likely to react to produce ethylene and hydrogen, rather than ethane. Based on the above experiments and simulation calculations, the hypothesis is proposed that at the actual operating temperature of the bushing, the C2H5· generated during aging is surrounded by intact dodecylbenzene molecules, making it easier to generate ethane by abstracting benzyl hydrogen from dodecylbenzene molecules.

[0055] Table 4. Enthalpy of reaction for three potential reactions at 298.15 K

[0056] 4. Reaction molecular dynamics simulation analysis of the characteristic gas generation process at thermal aging temperature. (1) Observation of the reaction pathway of free radicals in dodecylbenzene insulating oil For molecular dynamics, the reaction time that can be simulated is usually in the picosecond to nanosecond range. Higher temperatures are required to accelerate the reaction process. The temperature for simulating the decomposition of insulating oil in the literature is usually in the range of 1800-3000K. Within this temperature range, the existence time of C2H5· is relatively short. Conventional molecular simulation methods are difficult to simulate the process of C2H5· taking hydrogen atoms to generate ethane in the aging environment of insulating oil.

[0057] Considering the high reactivity and short lifespan of free radicals, a small amount of C2H5· can be added to the existing dodecylbenzene oil model to enable molecular dynamics simulation at a lower temperature, minimizing dodecylbenzene molecule decomposition and making it as close as possible to real-world conditions. The Pack function of the Amorphous Cell tool in the molecular simulation software is used to further refine the simulation. Figure 2 (c) shows the model with 5 C2H5· molecules added, and the result is as follows: Figure 7 As shown, molecular dynamics simulations of the reaction were performed using molecular simulation software. Figure 3 It can be seen that the dodecylbenzene oil model simulated at 1800K decomposed only a few molecules after 1500ps. Therefore, the decomposition simulation temperature was set to 1400K and 1600K, and the time parameters for relaxation and pyrolysis simulation were the same as those mentioned above.

[0058] The transformation pathways of C2H5· at the two temperatures are shown in Tables 5 and 6 below. At 1400 K, due to the lower temperature, only one C2H5· reacts with a dodecylbenzene molecule after 1 ns of pyrolysis to produce ethane. At 1600 K, only two C2H5· react with a dodecylbenzene molecule to produce ethane after 1 ns of pyrolysis, while two C2H5· undergo β-shear dehydrogenation to produce ethylene and H·.

[0059] Table 5. Reactions that generate C2H5· at 1400K and their frequency.

[0060] Table 6. Reactions that generate C2H5· at 1600K and their frequency.

[0061] (2) Determine the gas generation mechanism of dodecylbenzene insulating oil during thermal aging To determine the mechanism by which ethane, a characteristic gas, is generated during the thermal aging of dodecylbenzene oil, the formation process of ethane molecules in this pathway was studied using a pyrolysis temperature of 1600 K as an example. Figure 8 As shown, for ease of demonstration, all atoms that do not participate in the reaction are hidden. Figure 8 (a) shows the spatial position of C2H5· before attacking the dodecylbenzene molecule. Taking this frame as the starting time of the reaction, C2H5· first approaches the benzylic carbon of the dodecylbenzene molecule, such as... Figure 8 As shown in (b), at 0.110 ps, ​​the carbon-hydrogen bonds on the benzylic carbon and C1 are broken, as... Figure 8 As shown in (c), at 0.113 ps, the hydrogen ions released from the dodecylbenzene molecule form carbon-hydrogen bonds with the C atoms of C2H5·, and at 0.116 ps, as... Figure 8 As shown in (d), the carbon-hydrogen bond contracts to form a stable ethane molecule.

[0062] This result indicates that, at the actual operating temperature of the casing, C2H5· produced in dodecylbenzene oil readily reacts to form ethane. This is mainly because the large π bond of the benzene ring, under the influence of conjugation, significantly reduces the bond energy of the C-H bond connected to the benzylic carbon atom. With the participation of the dodecylbenzene molecule, the free energy of C2H5· reacting to form C2H6 is much lower than the free energy of C2H5· undergoing β-shear dehydrogenation to form ethylene, resulting in a higher proportion of ethane production from dodecylbenzene oil under aging conditions.

[0063] To verify the accuracy of the simulation results provided in this application, this application compares them with experimental results. For example... Figure 9 As shown, this application tested the gas generation characteristics of dodecylbenzene oil under long-term thermal aging at 90°C. The results showed that ethane was the main hydrocarbon gas in the dissolved gas of dodecylbenzene insulating oil, and its content increased significantly with increasing aging time and temperature. Experimental results showed that no acetylene gas was detected during the 40-day aging process, and the contents of methane, ethylene, and hydrogen were also much lower than those of ethane. This experimental phenomenon is highly consistent with the gas generation mechanism proposed in this application through reaction molecular dynamics and density functional theory simulations, namely, that under aging conditions, ethyl radicals generated in DDB oil tend to generate ethane rather than ethylene.

[0064] Furthermore, this application compares this simulation result with the results of molecular dynamics simulations of the decomposition of dodecylbenzene only at high temperatures, such as... Figure 3 As shown, the decomposition of small-molecule gaseous products is dominated by ethylene, which is several times more abundant than other small-molecule gases. Furthermore, the increasing trend in the number of ethylene molecules is highly correlated with the decreasing trend in the number of dodecylbenzene molecules. In the simulation at 2600 K, the amount of C2H4 initially increases rapidly with the decomposition of dodecylbenzene molecules, then decreases slowly. The production of ethane increases significantly with increasing temperature, but its total production at all three temperatures is far lower than that of ethylene and slightly lower than that of hydrogen. This simulation result is clearly inconsistent with experimental results. This comparative analysis indicates that relying solely on high-temperature simulations can lead to incorrect judgments about the gas production mechanism due to deviations in the reaction pathway from the actual thermodynamic equilibrium and kinetic competition relationship. It may mistakenly infer the dominant pathway of dodecylbenzene decomposition to ethylene at high temperatures as the main pathway under aging conditions.

[0065] In contrast, this application, by introducing density functional theory to calculate the reaction free energy over a wide temperature range, confirms the thermodynamic spontaneity and dominance of the ethane formation pathway in the low-temperature region. Furthermore, through molecular dynamics simulations of reactions involving specific free radicals at low temperatures, it directly observes and statistically records ethane formation events, thus verifying the ethane-dominated gas production mechanism at the atomic level. This comparison powerfully demonstrates that using only high-temperature molecular dynamics simulations as a comparative example cannot accurately reflect real aging chemical conditions. The multi-scale coupling strategy of this application effectively overcomes the distortion problem of high-temperature simulations, ensuring a high degree of consistency between simulation results and experimental phenomena, highlighting the technological advancement of this application.

[0066] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for analyzing the gas generation mechanism of insulating oil during thermal aging, characterized in that, Includes the following steps: Constructing a molecular dynamics simulation model for insulating oil; In the molecular dynamics simulation model of insulating oil, reaction molecular dynamics is used to simulate the pyrolysis process of insulating oil and to analyze the free radical intermediates generated by the thermal decomposition gas of insulating oil. Density functional theory was used to analyze the chemical process of the free radical intermediate and to deduce the generation mechanism of the insulating oil thermal aging gas. Under the condition of adding the free radical intermediate, the reaction molecular dynamics simulation of the gas generation process of insulating oil during thermal aging was carried out to verify the gas generation mechanism of insulating oil during thermal aging. The reaction molecular dynamics simulation temperature T1 when the pyrolysis process of insulating oil is simulated by reaction molecular dynamics in the insulating oil molecular dynamics simulation model and the reaction molecular dynamics simulation temperature T2 when the thermal aging gas generation process of insulating oil is simulated by reaction molecular dynamics under the condition of additional addition of the free radical intermediate satisfy the following relationship: T1 > T2. In the molecular dynamics simulation model of insulating oil, reaction molecular dynamics is used to simulate the pyrolysis process of insulating oil. The steps for analyzing the free radical intermediates generated by the thermal decomposition gas of insulating oil include the following: In the molecular dynamics simulation model of insulating oil, reactive molecular dynamics is used to simulate the pyrolysis process of insulating oil. The types of gases produced by the thermal decomposition of insulating oil at temperatures of 1800~2600K are analyzed to obtain the characteristic gases of thermal decomposition of insulating oil. The types and quantities of free radical intermediates produced by the characteristic gases of thermal decomposition of insulating oil are identified and tracked. Density functional theory was used to analyze the chemical process of the formation of the free radical intermediate, and the steps of the generation mechanism of the insulating oil thermal aging gas were deduced to include the following: Density functional theory was used in quantum chemistry software to simulate and analyze the free radical intermediate. The reaction free energy and enthalpy of different reaction pathways that generate the free radical intermediate and the characteristic gas of thermal decomposition of insulating oil were calculated in a wide temperature range. The spontaneity and exothermic characteristics of different reaction pathways in the low temperature region were verified. The kinetic and thermodynamic competition relationship of different generation pathways was compared. Based on the experimental and simulation calculation results, the generation mechanism of the thermal aging gas of insulating oil was inferred. And / or, under the condition of additional addition of the free radical intermediate, the steps of performing reaction molecular dynamics simulation of the gas generation process of insulating oil during thermal aging to verify the gas generation mechanism of insulating oil during thermal aging include the following processes: Four to seven free radical intermediates were added to the molecular dynamics simulation model of the insulating oil. The pyrolysis process of the insulating oil was simulated using molecular simulation software. The process of generating gas during thermal aging of the insulating oil at a temperature of 1400 to 1600 K was analyzed. The frequency of the generation of characteristic gases of thermal decomposition of the insulating oil by the reaction of the free radical intermediates was counted. The gas generation mechanism of thermal aging of insulating oil was verified and obtained.

2. The method for analyzing the gas generation mechanism of insulating oil during thermal aging according to claim 1, characterized in that, The insulating oil includes dodecylbenzene insulating oil.

3. The method for analyzing the gas generation mechanism of insulating oil during thermal aging according to claim 2, characterized in that, The steps for constructing a molecular dynamics simulation model of insulating oil include the following: A molecular dynamics simulation model of a linear dodecylbenzene monomer was constructed using molecular simulation software. Based on the molecular dynamics simulation model of the linear dodecylbenzene monomer, a molecular model of the dodecylbenzene insulating oil system was constructed and subjected to geometric optimization, annealing cycle, and kinetic equilibrium treatment to obtain the molecular dynamics simulation model of the insulating oil.

4. The method for analyzing the gas generation mechanism of insulating oil during thermal aging according to claim 3, characterized in that, The molecular dynamics simulation model of the linear dodecylbenzene monomer includes: a number of unit cells of the linear dodecylbenzene monomer, wherein the unit cells include cubic unit cells with a side length of 33~34 angstroms; And / or, the steps of constructing a molecular model of the dodecylbenzene insulating oil system based on the molecular dynamics simulation model of the linear dodecylbenzene monomer and performing geometric optimization, annealing cycling, and kinetic equilibrium processing to obtain the molecular dynamics simulation model of the insulating oil include the following processes: The molecular dynamics simulation model of the linear dodecylbenzene monomer was imported into molecular dynamics simulation software. Using the CHO force field of the carbon, hydrogen, and oxygen atom system, two annealing cycles from 273 K to 573 K were performed under an isothermal and isobaric ensemble. The heating and cooling times in each cycle were 95-105 ps, and the temperature was maintained at 573 K and 273 K for 45-55 ps, respectively. The total duration of the annealing cycles was 590-610 ps. The boundary was set as a periodic boundary, and the pressure was 1 standard atmosphere. Then, relaxation was performed under a canonical ensemble at 273 K for a total duration of 390-410 ps.

5. The method for analyzing the gas generation mechanism of insulating oil during thermal aging according to claim 1, characterized in that, The characteristic gases of thermal decomposition of the insulating oil include H2, CH4, C2H6, C2H4 and C2H2; And / or, the free radical intermediate of the C2H6 includes C2H5·.

6. A device for analyzing the gas generation mechanism of insulating oil during thermal aging, characterized in that, To implement the method as described in any one of claims 1-5, comprising: The model building module is used to build molecular dynamics simulation models of insulating oil; The pyrolysis simulation module is used to simulate the pyrolysis process of insulating oil using reaction molecular dynamics in the insulating oil molecular dynamics simulation model, and to analyze the free radical intermediates generated by the thermal decomposition gas of insulating oil. The mechanism prediction module uses density functional theory to analyze the chemical process of the free radical intermediate and predicts the generation mechanism of the insulating oil thermal aging gas. Mechanism verification module: used to perform reaction molecular dynamics simulation of the gas generation process of insulating oil during thermal aging under the condition of additional addition of the free radical intermediate, and to verify the gas generation mechanism of insulating oil during thermal aging; The reaction molecular dynamics simulation temperature T1 when the pyrolysis process of insulating oil is simulated using reaction molecular dynamics in the insulating oil molecular dynamics simulation model and the reaction molecular dynamics simulation temperature T2 when the thermal aging gas generation process of insulating oil is simulated using reaction molecular dynamics under the condition of additional addition of the free radical intermediate satisfy the following relationship: T1 > T2.

7. The device for analyzing the gas generation mechanism of insulating oil during thermal aging according to claim 6, characterized in that, The model building module includes: Monomer building blocks are used to construct unit cells for linear dodecylbenzene monomer molecules, wherein the unit cells are cubes with a side length of 33-34 angstroms; The system optimization unit is used to perform two annealing cycles from 273K to 573K under isothermal and isobaric ensembles. The heating and cooling time for each cycle is 95~105ps, and the holding time at 573K and 273K is 45~55ps, with a total annealing time of 590~610ps. Then, it relaxes at 273K under a canonical ensemble for 390~410ps. And / or, the pyrolysis simulation module includes: Gas identification unit is used to identify characteristic gases of thermal decomposition of insulating oil, including H2, CH4, C2H6, C2H4, and C2H2. A free radical tracking unit is used to track the type and quantity of C2H5·, a free radical intermediate of C2H6; And / or, the mechanism verification module includes: Intermediate injection unit, used to add 4 to 7 free radical intermediates to the molecular dynamics simulation model of insulating oil; The reaction statistics unit is used to count the frequency of the formation of characteristic gases from thermal decomposition of free radical intermediates.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-5.

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