Method for obtaining characteristic decomposition products of latent failure of nozzle ablation of SF6 circuit breaker

Abstract

The application provides a method for obtaining characteristic decomposition products of SF6 circuit breaker nozzle ablation latent failure, comprising the following steps: constructing a molecular model of PTFE of the SF6 circuit breaker nozzle, and filling the molecular model into a three-dimensional periodic model box; performing structure optimization, annealing and relaxation on the model box to obtain an optimized model; performing molecular dynamics calculation on the optimized model to simulate the process of PTFE molecular cracking, and obtaining decomposition components of the process of PTFE molecular cracking; and performing statistical calculation on the decomposition components to complete the research on the decomposition mechanism of the PTFE material of the SF6 circuit breaker nozzle. The method studies the decomposition path of the nozzle PTFE from the microscopic atomic angle through molecular dynamics calculation, excludes the influence of factors such as impurities (H2O and O2), adsorbents and other insulating materials, and the result is reliable, and the cracking mechanism of the nozzle PTFE material is effectively clarified.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electric power and relates to a method for obtaining characteristic decomposition products of latent failure of nozzle ablation of an SF6 circuit breaker. BACKGROUND

[0002] With the rapid development of the electric power industry, the safe and reliable operation of high-voltage switchgear is of great importance. The nozzle is a core component of the arc control and high-speed gas blow creation in the arc extinguishing device of a high-voltage SF6 circuit breaker. When the circuit breaker breaks a short-circuit current, the high-temperature and high-energy arc will cause the nozzle surface to ablate, and the ablation will greatly damage the breaking performance of the circuit breaker, and even may cause breaking failure. Therefore, the degree of nozzle ablation is an important factor affecting the electric life of the circuit breaker, and timely and effective detection of the nozzle ablation condition has important significance for ensuring the safe and stable operation of the circuit breaker. The nozzle is mainly composed of polytetrafluoroethylene (PTFE) material, and the ablation of the nozzle will cause the PTFE material on the surface to vaporize, and theoretically the generated PTFE vapor will participate in the generation reaction of SF6 decomposition products and significantly affect the types and concentrations of some SF6 decomposition products. Therefore, the degree of ablation of the nozzle material can be evaluated through decomposition product analysis, and important criteria for whether the circuit breaker needs to be shut down can be provided.

[0003] However, the generation reaction of decomposition products in the arc extinguishing chamber of the circuit breaker after arc discharge is very complex, and at present, only the types of decomposition products can be detected through experiments, while the influence of impurities such as H2O and O2, adsorbents and other insulating materials needs to be considered. It is difficult to effectively determine which products are related to the ablation of the nozzle material, making it difficult to select the SF6 characteristic decomposition products of the ablation of the nozzle material and the concentration threshold, and the decomposition path of the nozzle material and its correlation with the SF6 decomposition products are not clear. SUMMARY

[0004] In view of the problems in the prior art, the application provides a method for obtaining characteristic decomposition products of latent failure of nozzle ablation of an SF6 circuit breaker, thereby solving the technical problem that the relationship between the products in the arc extinguishing chamber of the circuit breaker after arc discharge and the latent failure of nozzle ablation cannot be determined through experimental means in the prior art.

[0005] The application is achieved by the following technical solutions:

[0006] A method for obtaining characteristic decomposition products of latent failure of nozzle ablation of an SF6 circuit breaker, comprising the following steps:

[0007] S1: constructing a molecular model of PTFE of the nozzle of the SF6 circuit breaker, and filling the molecular model into a three-dimensional periodic model box;

[0008] S2: performing structure optimization, annealing and relaxation on the model box to obtain an optimized model;

[0009] S3: performing molecular dynamics calculation on the optimized model to simulate the process of PTFE molecule cracking, and obtaining a decomposition component of the process of PTFE molecule cracking;

[0010] S4: performing statistical calculation on the decomposition component to obtain the SF6 circuit breaker nozzle ablation latent fault characteristic decomposition product.

[0011] Preferably, in the step S1, the PTFE molecule model is constructed by the Build function of the Materials Studio software, and the PTFE molecule model is randomly filled into a three-dimensional periodic box, and the density of the PTFE molecule model is set.

[0012] Preferably, in the step S2, the constructed model is optimized by the Forcite module of the Materials Studio software.

[0013] Preferably, the optimization process specifically comprises: first, the structure of the constructed PTFE molecule model is optimized by an iterative program, then the structure is subjected to five cycles of periodic annealing simulation, the frame model with the lowest energy is selected, and relaxation simulation is respectively performed under NVT and NPT ensembles, and the optimization process is completed.

[0014] Preferably, when the relaxation simulation is performed under the NVT ensemble, the constant temperature is maintained by changing the Newtonian classical motion equation through a thermostat; when the relaxation simulation is performed under the NPT ensemble, the temperature and pressure are kept constant by a thermostat and a constant pressure device.

[0015] Preferably, the annealing simulation process specifically comprises determining the conformational space of low-energy structure by periodically increasing and then decreasing the temperature of the classical dynamics trajectory.

[0016] Preferably, in the step S3, the ReaxFF6.0 force field of the GULP module of the Materials Studio software is used to perform molecular dynamics calculation on the optimized model to simulate the process of PTFE molecule cracking.

[0017] An SF6 circuit breaker nozzle ablation latent fault characteristic decomposition product acquisition system, comprising:

[0018] A model construction module: the model construction module is used to construct a molecular model of PTFE of an SF6 circuit breaker nozzle, and fill the molecular model into a three-dimensional periodic model box;

[0019] A model optimization module: the model optimization module is used to optimize the structure of the model box, anneal and relax, and obtain an optimized model;

[0020] The model running module is configured to perform molecular dynamics calculation on the optimized model, simulate the process of PTFE molecular cracking, and obtain decomposition components of the process of PTFE molecular cracking.

[0021] The result output module is configured to perform statistical calculation on the decomposition components, and output the decomposition mechanism of the PTFE material of the SF6 circuit breaker nozzle.

[0022] A terminal device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the above method when executing the computer program.

[0023] A computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the above method.

[0024] Compared with the prior art, the present application has the following beneficial technical effects:

[0025] A method for obtaining characteristic decomposition products of SF6 circuit breaker nozzle ablation latent fault, through molecular dynamics calculation, the decomposition path of the nozzle PTFE material is studied from the micro atomic angle, the process of PTFE molecular cracking is simulated, the decomposition components of the process of PTFE molecular cracking are obtained, and statistical calculation is performed on the decomposition components, the action process of the cracking products of the nozzle PTFE material and H2O, O2 and SF6 decomposition products is clarified, and the corresponding reaction products are obtained, the reaction products related to PTFE material cracking are effectively clarified, the relationship between the products in the circuit breaker arc chamber after arc discharge and the nozzle ablation latent fault is determined, and a reference basis is provided for selecting characteristic decomposition products of nozzle ablation fault diagnosis.

[0026] Further, in step S1, the PTFE molecular model is constructed by the Build function of the Materials Studio software, and the PTFE molecular model is randomly filled into a three-dimensional periodic box, and the density of the PTFE molecular model is set, which can effectively prevent unreasonable initial structure.

[0027] Further, the specific process of optimizing the constructed model is that the constructed PTFE molecular model is first optimized by an iterative program, then the structure is subjected to five cycles of periodic annealing simulation, the frame model with the lowest energy is selected, and relaxation simulation is performed under NVT and NPT ensembles, and the optimization process is completed, which can make the initial model structure more reasonable.

[0028] Further, the annealing simulation process is specifically to determine the conformation space of low-energy structure by periodically increasing and then reducing the temperature of the classical dynamics trajectory, effectively avoiding trapping the simulated structure in a local energy minimum conformation.

[0029] Further, in step S3, the optimized model is subjected to molecular dynamics calculation by the ReaxFF 6.0 force field of the GULP module of the Materials Studio software, the process of PTFE molecular cracking is simulated, the ReaxFF force field is the current most mainstream chemical reaction force field, and the smooth transition between non-bonding state and single, double and triple bond states can be realized on the basis of bond level, so as to describe the chemical reaction of a complex system. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows, and it should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0031] Figure 1 The flow chart for the method for obtaining the characteristic decomposition products of SF6 circuit breaker nozzle ablation latent fault in the present application;

[0032] Figure 2 The module connection schematic diagram of the system for obtaining the characteristic decomposition products of SF6 circuit breaker nozzle ablation latent fault in the present application;

[0033] Figure 3 The PTFE molecular model constructed in embodiment 2 of the present application;

[0034] Figure 4 The optimized PTFE molecular model in embodiment 2 of the present application;

[0035] Figure 5 The decomposition path of the PTFE molecule constructed based on molecular simulation in the present application. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application, and obviously, the described embodiments are part of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the application provided in the accompanying drawings is not intended to limit the scope of the application claimed, but merely represents selected embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.

[0038] It should be noted that similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0039] In the description of the embodiments of the application, it should be noted that if the terms "upper", "lower", "horizontal", "inner" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the application is usually placed, it is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application. In addition, the terms "first", "second" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0040] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0041] In the description of the embodiments of the application, it should also be noted that unless otherwise explicitly specified and limited, if the terms "arrangement", "installation", "connection", "connection" appear, they should be understood in a broad sense, for example, they can be fixedly connected, or they can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium; can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0042] The application will be described in further detail below in conjunction with the accompanying drawings:

[0043] Example 1

[0044] A method for obtaining characteristic decomposition products of SF6 circuit breaker nozzle ablation latent failure, all calculations in the application are completed in the Materials Studio software, and the specific process is as shown in Figure 1 The method comprises the following steps:

[0045] S1: constructing a molecular model of PTFE of a SF6 circuit breaker nozzle in a molecular simulation software, and filling the molecular model into a three-dimensional periodic model box; in this step, the PTFE molecular model is constructed by the Build function of the Materials Visualizer module of the Materials Studio software, and the PTFE molecular model is randomly filled into a three-dimensional periodic box, and the density of the PTFE molecular model is set, the density of the PTFE molecular model is set to a lower value to prevent the initial model structure from being unreasonable.

[0046] S2: structure optimization, annealing and relaxation of the model box to obtain an optimized model; in this step, the constructed model is optimized by the Forcite module of the Materials Studio software, and the optimization process is as follows: first, the structure of the constructed PTFE molecular model is optimized by an iterative program, i.e. an energy minimization process; then, the PTFE molecular model after structure optimization is subjected to five cycles of periodic annealing simulation, and the frame model with the lowest energy is selected, and relaxation simulation is carried out under NVT and NPT ensembles to complete the optimization process. The relaxation under the NVT and NPT ensembles is the dynamics task of the Forcite module, which can simulate how the atoms in the structure move as a function of time under the influence of calculated forces by solving Newton's classical equations of motion. The NVT ensemble (canonical ensemble) represents a system composed of a fixed number of particles (N), a fixed volume (V) and a fixed temperature (T). Preferably, when the relaxation simulation is carried out under the NVT ensemble (canonical ensemble), the constant temperature is maintained by a thermostat in Newton's classical equations of motion; when the relaxation simulation is carried out under the NPT ensemble, the constant temperature and pressure are maintained by a thermostat and a constant pressure device. In addition, the annealing simulation process is to determine the conformational space of low-energy structures by periodically increasing and then decreasing the temperature of the classical dynamics trajectory to avoid trapping the structure in a locally energy-minimized conformation. In this step, the force field of all calculation tasks is selected as COMPASS III.

[0047] S3: using ReaxFF force field to perform molecular dynamics calculation on the optimized model, simulating the process of PTFE molecular cracking, and obtaining the decomposition components of the PTFE molecular cracking process; in this step, the ReaxFF 6.0 force field of the GULP module of the Materials Studio software is used to perform molecular dynamics calculation on the optimized model, and the process of PTFE molecular cracking is simulated. The ReaxFF force field is the most mainstream chemical reaction force field at present, which can realize smooth transition between non-bonding state and single, double and triple bonding state on the basis of bond level, so as to describe the chemical reaction of complex system. Molecular dynamics calculation using ReaxFF force field does not need prior knowledge input and chemical intuition, and is an important method to obtain the reaction mechanism of pyrolysis process.

[0048] S4: performing statistical calculation on the decomposition components to complete the research on the decomposition mechanism of the PTFE material of the SF6 circuit breaker nozzle.

[0049] The application provides a research method for the decomposition mechanism of the PTFE material of the SF6 circuit breaker nozzle based on molecular simulation, molecular dynamics calculation is performed by using the mainstream chemical reaction force field ReaxFF, the decomposition path of the nozzle PTFE material is researched from the micro atomic angle, the influence of factors such as H2O and O2 impurities, adsorbents and other insulating materials is excluded, the decomposition products calculated are consistent with the experimental results, and the results have reliability. The cracking mechanism of the nozzle PTFE material is determined, and the influence of the cracking of the PTFE material on the SF6 decomposition products is also determined, which provides a reference basis for the selection of characteristic decomposition products for the nozzle ablation fault diagnosis, and can also provide a reference for the related research on the decomposition mechanism of other metal insulating materials.

[0050] As Figure 2 shown, it is a module connection schematic diagram of a SF6 circuit breaker nozzle ablation latent fault characteristic decomposition product acquisition system in the application, which comprises:

[0051] The model construction module is used for constructing a molecular model of the SF6 circuit breaker nozzle PTFE, and filling the molecular model into a three-dimensional periodic model box.

[0052] The model optimization module is used for structure optimization, annealing and relaxation of the model box, and obtaining an optimized model.

[0053] The model running module is used for molecular dynamics calculation on the optimized model, simulating the process of PTFE molecular cracking, and obtaining the decomposition components of the PTFE molecular cracking process.

[0054] A result output module is configured to statistically calculate the decomposed components to obtain the SF6 circuit breaker nozzle ablation latent fault characteristic decomposition product.

[0055] In addition, an embodiment of the terminal device is provided. The terminal device includes a processor, a memory, and a computer program stored in the memory and executable on the processor. The processor implements the steps of the above various method embodiments when executing the computer program. Alternatively, the processor implements the functions of the modules / units in the above various device embodiments when executing the computer program.

[0056] The computer program can be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present application.

[0057] The terminal device can be a desktop computer, a notebook computer, a palm computer, a cloud server, and the like. The terminal device can include, but is not limited to, a processor and a memory.

[0058] The processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, and the like.

[0059] The memory can be used to store the computer program and / or modules. The processor realizes various functions of the terminal device by running or executing the computer program and / or modules stored in the memory, and calling data stored in the memory.

[0060] The modules / units integrated in the terminal device, if realized in the form of software function units and sold or used as independent products, can be stored in a computer-readable storage medium. Based on such understanding, all or part of the processes in the method of the above-mentioned embodiments can also be completed by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of each method embodiment when executed by a processor. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or some intermediate forms, etc. The computer-readable medium can include any entity or device, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. that can carry the computer program code. It should be noted that the computer-readable medium can include or exclude contents according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0061] Embodiment 2

[0062] The method for researching the PTFE material decomposition mechanism of the SF6 circuit breaker nozzle described in this embodiment is all completed in the molecular simulation software Materials Studio, and the specific process is as shown in Figure 1 , which includes the following steps:

[0063] S1: Construct the nozzle PTFE molecular model in the molecular simulation software, and fill the model into a three-dimensional periodic box.

[0064] In specific implementation, the Build function of the Materials Visualizer module can be used to select BuildPolymers-Homopolymer to establish a homopolymer PTFE molecular chain, and the chain length is set to 5 and the chain number is set to 1. Then the Construction method of the Amorphous Cell module is used to randomly fill the PTFE chain into the three-dimensional periodic box. In this example, 2 PTFE chains are loaded, and the initial density of PTFE is set to 1.1 g / cm 3 , at this time the lattice vector is Here, the density of PTFE is first set to a small value, and then the box is slowly compressed to reach the desired density value during NPT simulation, which is to ensure that the PTFE molecule has a reasonable initial structure. For example, Figure 3The initial PTFE model box is shown. In the figure, the gray round ball represents the C atom, and the blue round ball represents the F atom.

[0065] S2: Structure optimization, annealing and relaxation are performed on the model box to obtain the optimized stable structure.

[0066] Specifically, the Smart method of the Forcite module is used to perform 50000-step structure optimization on the model, that is, to perform an energy minimization process through an iterative procedure. Among them, the energy convergence threshold is 10 -5 kcal / mol, and the force convergence threshold is The COMPASS III force field is selected.

[0067] Then, periodic annealing simulation is performed on the model under the NVT ensemble for five cycles. The annealing task is to explore the conformational space of low-energy structures by periodically increasing and then decreasing the temperature of the classical dynamics trajectory to avoid trapping the structure in a local energy minimum conformation. Therefore, the temperature range of this annealing task is 300-800K, ensuring that the highest temperature exceeds the decomposition temperature of the PTFE molecule.

[0068] After the simulation is completed, the frame with the lowest energy is selected, and 1ns of relaxation is performed under the NVT and NPT ensembles, respectively, to rationalize the initial structure. The dynamics task of the Forcite module can simulate how the atoms in the structure move as a function of time under the influence of calculated forces by solving Newton's classical equations of motion. Before performing dynamics calculations, a thermodynamic ensemble should first be selected, and relevant parameters should be set, the simulation time step should be defined, and the simulation temperature should be selected. The ensemble is a mathematical method used to represent the states that a system can occupy under certain constraints. The canonical ensemble (NVT) represents a system composed of a fixed number of particles (N), a fixed volume (V), and a fixed temperature (T). During simulation, the constant temperature is maintained by appropriately changing Newton's classical equations of motion using a thermostat. For the NPT ensemble, the temperature and pressure are maintained constant during simulation by using a thermostat and a constant pressure device. In this example, the simulation temperature is set to 298K, the time step is 1.0fs, the total simulation time is 1ns, the force field is COMPASS III, and the temperature control method is Nose. The pressure under the NPT ensemble is set to 1.01*10 -3 GPa, the temperature control method is Nose, and the pressure control method is Berendsen. After the simulation is completed, the density of the PTFE molecule is 1.865g / cm 3 , and the lattice vector is The optimized PTFE model box is shown in Figure 4 .

[0069] S3: Adopt ReaxFF force field to perform molecular dynamics calculation on the structure optimized in step, simulate the process of PTFE molecular cracking, and obtain the decomposition components of the PTFE molecular cracking process;

[0070] Specifically, the above model is subjected to 1 ns of dynamics calculation using the ReaxFF 6.0 force field of the GULP module. The dynamics calculation is performed under the NVT ensemble, the time step is 0.1 fs, and the temperature is set to 1500 K. After the calculation, the decomposition components obtained are statistically calculated to determine the decomposition process of the nozzle PTFE material and its influence on the SF6 decomposition products.

[0071] Among them, the decomposition path of the PTFE molecule is as shown in Figure 5 , specifically: the PTFE chain first breaks at an arbitrary C-C bond in the middle under the action of high temperature to form two long carbon chain radicals; then, the C-C bonds at the tail of the long carbon chain radical continuously break to generate a large amount of CF2 molecules; under the action of heat, CF2 will absorb energy and break the C-F covalent bond to form CF, C, F and other particles:

[0072] …CF2-CF2-CF2-CF2-CF2…→…CF2-CF2·→CF2

[0073] CF2→CF+F

[0074] CF→C+F

[0075] These particles will further react with SF6 gas, trace amounts of H2O and O2 impurities and particles generated by their decomposition in the SF6 switchgear under the further action of heat and electron collision, and eventually form CF4, C2F6, CO2, CO and other SF6 decomposition products. The results are consistent with the actual test results. The reaction path is as follows:

[0076] CF2+SF6→CF4+SF4

[0077] CF2+SF4→CF4+SF2

[0078] CF2+F→CF3

[0079] CF3+F→CF4

[0080] CF3+SF→CF4+S

[0081] CF3+SF X →CF4+SF5(X=2~6)

[0082] CF3+CF3→C2F6

[0083] C+O→CO

[0084] CO + O -> CO2

[0085] Therefore, CF4, C2F6, CO2 and CO have a reaction relationship with the decomposition of the nozzle PTFE material, and in combination with actual test results, it is determined that CF4, C2F6 and CO2 can be used as characteristic decomposition products for diagnosing latent faults of the nozzle ablation of the circuit breaker.

[0086] To sum up, the application discloses a research method of SF6 circuit breaker nozzle PTFE material decomposition mechanism and products based on molecular simulation, performs molecular dynamics calculation from a micro atomic level, overcomes the defects that macroscopic experiments are difficult to directly observe and have many influencing factors, and determines the influence of nozzle PTFE material decomposition on SF6 decomposition products, thereby providing a theoretical basis for selecting characteristic decomposition products for diagnosing latent faults of the nozzle ablation of the circuit breaker. The application discloses a research method of SF6 circuit breaker nozzle PTFE material decomposition mechanism based on molecular simulation, and belongs to the technical field of electric power.

[0087] The above merely describes preferred embodiments of the application, but is not intended to limit the application, and various modifications and changes can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A method for obtaining signature decomposition products of SF6 circuit breaker nozzle ablation incipient faults, characterized in that, The method comprises the following steps: S1: constructing a PTFE molecular model of the SF6 circuit breaker nozzle, and filling the PTFE molecular model into a three-dimensional periodic model box; S2: performing structure optimization, annealing and relaxation on the model box to obtain an optimized model; S3: performing molecular dynamics calculation on the optimized model to simulate the process of PTFE molecular cracking, and obtaining decomposition components of the process of PTFE molecular cracking; In step S1, the PTFE molecular model is constructed by the Build function of the Materials Studio software, and the PTFE molecular model is randomly filled into a three-dimensional periodic box, and the density of the PTFE molecular model is set; In step S2, the constructed model is optimized by the Forcite module of the Materials Studio software; The optimization process specifically includes: first, the structure of the constructed PTFE molecular model is optimized by an iterative program, then the structure is subjected to five cycles of periodic annealing simulation, the frame model with the lowest energy is selected, and relaxation simulation is performed under NVT and NPT ensembles, and the optimization process is completed; When the relaxation simulation is performed under the NVT ensemble, the constant temperature is maintained by a thermostat changing the Newtonian classical motion equation; when the relaxation simulation is performed under the NPT ensemble, the temperature and pressure are kept constant by a thermostat and a constant pressure device; The annealing simulation process specifically includes determining the conformational space of low-energy structures by periodically increasing and then decreasing the temperature of the classical dynamics trajectory. In the step S3, the ReaxFF 6.0 force field of the GULP module of the Materials Studio software is used to perform molecular dynamics calculation on the optimized model to simulate the process of PTFE molecular cracking.

2. A method of obtaining decomposition products of latent defects of a nozzle ablation of an SF6 circuit breaker according to claim 1, characterized in that, A method for obtaining a SF6 circuit breaker nozzle ablation latent fault characteristic decomposition product according to any one of claims 1-2, comprising:

3. A system for obtaining signature decomposition products of SF6 circuit breaker nozzle ablation incipient faults, comprising: a model construction module: the model construction module is used to construct a PTFE molecular model of the SF6 circuit breaker nozzle, and fill the PTFE molecular model into a three-dimensional periodic model box; a model optimization module: the model optimization module is used to perform structure optimization, annealing and relaxation on the model box to obtain an optimized model; a model running module: the model running module is used to perform molecular dynamics calculation on the optimized model to simulate the process of PTFE molecular cracking, and obtain decomposition components of the process of PTFE molecular cracking; a result output module: the result output module is used to perform statistical calculation on the decomposition components, and output the decomposition mechanism of the SF6 circuit breaker nozzle PTFE material. The processor executes the computer program to realize the steps of the method according to any one of claims 1-2.

4. A terminal device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The computer program is executed by the processor to realize the steps of the method according to any one of claims 1-2.

5. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 4. ​

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