Insulating oil insulation aging state determination method, device, equipment and medium

Abstract

The application relates to an insulating oil insulation aging state determination method and device, computer equipment, a computer readable storage medium and a computer program product. The method comprises the following steps: constructing a single molecule model corresponding to a target molecule in a composition molecule of insulating oil by using a molecular simulation tool; acquiring an extreme electric field strength corresponding to the destruction of the single molecule model, and determining a test electric field strength interval according to the extreme electric field strength; acquiring a dipole moment, a polarizability, an orbital energy level and a state density corresponding to different test electric field strengths in the test electric field strength interval; determining a reaction site of the single molecule model under the extreme electric field strength according to the dipole moment, the polarizability, the orbital energy level and the state density; acquiring target infrared spectrum information corresponding to the reaction site of the single molecule model; and matching and comparing the target infrared spectrum information with infrared spectrum information of an insulating oil to be evaluated, so as to obtain an insulation aging state of the insulating oil to be evaluated. The method can improve the evaluation efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of quantum chemical calculation and infrared spectroscopy, in particular to an insulating oil insulation aging state determination method and device, computer equipment, computer readable storage medium and computer program product. BACKGROUND

[0002] At present, power capacitors are widely used in power grid systems, and the insulation performance of power capacitors is the key to ensure the stable operation of power capacitors. Therefore, the insulation performance of the liquid dielectric material (such as insulating oil) of the power capacitor is crucial to the stable operation of the power grid.

[0003] The aging of the power capacitor is associated with many complex factors of the power grid. At present, there are great difficulties in precise fault diagnosis of the aging state of the insulating oil of the power capacitor. The aging state can only be obtained through complex tests, resulting in low efficiency of the evaluation of the insulation aging state of the insulating oil of the power capacitor. SUMMARY

[0004] Therefore, it is necessary to provide an insulating oil insulation aging state determination method, device, computer equipment, computer readable storage medium and computer program product capable of efficiently evaluating the insulation aging state of the insulating oil in view of the above technical problems.

[0005] In a first aspect, the present application provides an insulating oil insulation aging state determination method, comprising:

[0006] A single molecule model corresponding to a target molecule in a component molecule of the insulating oil is constructed by using a molecular simulation tool; the insulating oil comprises at least one type of component molecule;

[0007] An extreme electric field strength corresponding to the destruction of the single molecule model is obtained, and a test electric field strength interval is determined according to the extreme electric field strength;

[0008] The dipole moment, polarizability, orbital energy level and state density corresponding to different test electric field strengths in the test electric field strength interval are obtained;

[0009] The reaction site of the single molecule model under the extreme electric field strength is determined according to the dipole moment, the polarizability, the orbital energy level and the state density;

[0010] Target infrared spectrum information corresponding to the reaction site of the single molecule model is obtained; the target infrared spectrum information is used for matching and comparison with infrared spectrum information of a to-be-evaluated insulating oil, so as to obtain the insulation aging state of the to-be-evaluated insulating oil.

[0011] In one of the embodiments, the constructing, by the molecular simulation tool, a single-molecule model corresponding to the target molecule in the constituent molecule of the insulating oil comprises:

[0012] constructing, by the molecular simulation tool, an initial single-molecule model corresponding to the target molecule in the constituent molecule of the insulating oil;

[0013] optimizing the initial single-molecule model at a basis set level of PM3 to obtain a single-molecule stable structure at a lowest molecular energy;

[0014] determining the single-molecule stable structure as the single-molecule model corresponding to the target molecule.

[0015] In one of the embodiments, the acquiring the extreme electric field strength corresponding to the destruction of the single-molecule model comprises:

[0016] applying, by the molecular simulation tool, an electric field in a molecular chain direction to the single-molecule model and gradually increasing the electric field strength of the electric field according to a preset electric field strength increment until the single-molecule model is destroyed, to acquire the extreme electric field strength corresponding to the destruction of the single-molecule model.

[0017] In one of the embodiments, the acquiring the dipole moment, the polarizability, the orbital energy level and the state density of the single-molecule model corresponding to different test electric field strengths in the test electric field strength interval comprises:

[0018] performing, by a quantum chemistry method, molecular simulation on the single-molecule model corresponding to different test electric field strengths in the test electric field strength interval to obtain a dipole moment of the single-molecule model corresponding to different test electric field strengths in the molecular simulation process; and acquiring, according to the dipole moment, a polarizability corresponding to the single-molecule model.

[0019] acquiring, by a frontier orbital theory, an orbital energy level of the single-molecule model corresponding to different test electric field strengths in the test electric field strength interval; and acquiring, according to the orbital energy level, a state density of the single-molecule model; wherein the orbital energy level comprises an energy level of a highest occupied molecular orbital and an energy level of a lowest unoccupied molecular orbital.

[0020] In one of the embodiments, the performing, by a quantum chemistry method, molecular simulation on the single-molecule model corresponding to different test electric field strengths in the test electric field strength interval to obtain a dipole moment of the single-molecule model corresponding to different test electric field strengths in the molecular simulation process comprises:

[0021] obtaining a first Hamiltonian of the single-molecule model under no applied electric field and a second Hamiltonian of the single-molecule model corresponding to different test electric field strengths in the test electric field strength interval by using a quantum chemistry method;

[0022] obtaining a dipole moment of the single-molecule model corresponding to the test electric field strength according to the first Hamiltonian, the second Hamiltonian, and the test electric field strength corresponding to the second Hamiltonian.

[0023] In one of the embodiments, the obtaining the density of states of the single-molecule model according to the orbital energy levels comprises:

[0024] obtaining an energy gap of the single-molecule model corresponding to the test electric field strength interval according to the energy level of the highest occupied molecular orbital and the energy level of the lowest unoccupied molecular orbital;

[0025] obtaining the density of states of the single-molecule model according to the orbital energy levels and the energy gap.

[0026] In a second aspect, the present application further provides an insulation oil insulation aging state determination device, comprising:

[0027] a single-molecule model construction module configured to construct a single-molecule model corresponding to a target molecule in a component molecule of insulation oil by using a molecular simulation tool; the insulation oil comprises at least one type of component molecule;

[0028] a model data obtaining module configured to obtain an extreme electric field strength corresponding to a destruction of the single-molecule model, determine a test electric field strength interval according to the extreme electric field strength, and obtain a dipole moment, a polarizability, an orbital energy level, and a density of states of the single-molecule model corresponding to different test electric field strengths in the test electric field strength interval;

[0029] a reaction site determining module configured to determine a reaction site of the single-molecule model under the extreme electric field strength according to the dipole moment, the polarizability, the orbital energy level, and the density of states;

[0030] an infrared spectrum obtaining module configured to obtain target infrared spectrum information of the single-molecule model corresponding to the reaction site; the target infrared spectrum information is used to match and compare with infrared spectrum information of a to-be-evaluated insulation oil to obtain an insulation aging state of the to-be-evaluated insulation oil.

[0031] In a third aspect, the present application further provides a computer device comprising a memory and a processor, the memory stores a computer program, and the processor implements the steps of the method in the first aspect when executing the computer program.

[0032] In a fourth aspect, the present application also provides a computer readable storage medium, having stored thereon a computer program, which, when executed by a processor, implements the steps of the method in the first aspect.

[0033] In a fifth aspect, the present application also provides a computer program product, comprising a computer program which, when executed by a processor, implements the steps of the method in the first aspect.

[0034] The insulation oil insulation aging state determination method, device, computer device, computer readable storage medium and computer program product described above, a single molecule model corresponding to a target molecule in a component molecule of the insulation oil is constructed by using a molecular simulation tool; the insulation oil comprises at least one type of component molecule; then, an extreme electric field strength corresponding to a destruction of the single molecule model is obtained, and a test electric field strength interval is determined according to the extreme electric field strength; then, a dipole moment, a polarizability, an orbital energy level and a state density corresponding to different test electric field strengths in the test electric field strength interval are obtained; then, a reaction site of the single molecule model under the extreme electric field strength is determined according to the dipole moment, the polarizability, the orbital energy level and the state density; finally, target infrared spectrum information corresponding to the reaction site of the single molecule model is obtained; and the target infrared spectrum information is matched and compared with infrared spectrum information of the insulation oil to be evaluated, so as to obtain the insulation aging state of the insulation oil to be evaluated. The present application constructs a single molecule model, and obtains the electric field response characteristics of the single molecule model, that is, the response changes of the dipole moment, the polarizability, the orbital energy level and the state density, and associates the electric field response characteristics with the infrared spectrum of the reaction site of the single molecule model. Finally, the infrared spectrum information of the reaction site is matched and compared with the infrared spectrum information of the insulation oil to be evaluated. The degree of change of the reaction site in the insulation oil to be evaluated can be evaluated, and then the insulation aging state of the insulation oil to be evaluated is obtained. Therefore, only the infrared spectrum information of the insulation oil to be evaluated and the target infrared spectrum information of the reaction site are needed to obtain the insulation aging state, the efficiency of obtaining the insulation aging state is improved, the process of obtaining the insulation aging state is simplified compared with a traditional complex test process, and resource consumption can be reduced. Meanwhile, the insulation aging state of the insulation oil is determined according to the characteristics of the reaction site at a microscopic molecular level, and the accuracy of evaluating the insulation aging state can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the description of the embodiments of the present application or the related art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0036] Figure 1Flowchart of a method for determining the aging state of insulating oil in an embodiment;

[0037] Figure 2 Flowchart of a method for constructing a single-molecule model corresponding to a target molecule in a constituent molecule of insulating oil using a molecular simulation tool in an embodiment;

[0038] Figure 3 Structural diagram of a molecular model of MBT in an embodiment;

[0039] Figure 4 Structural diagram of a molecular model of DBT in an embodiment;

[0040] Figure 5 Curve diagram of the change in bond length of MBT (a) and DBT (b) molecules in an embodiment;

[0041] Figure 6 Structural diagram of the change in molecular bond breaking of a MBT molecule in an embodiment;

[0042] Figure 7 Structural diagram of the change in molecular bond breaking of a DBT molecule in an embodiment;

[0043] Figure 8 Curve diagram of the change in total energy, dipole moment, and polarizability of a MBT molecule in an embodiment;

[0044] Figure 9 Curve diagram of the change in total energy, dipole moment, and polarizability of a DBT molecule in an embodiment;

[0045] Figure 10 Curve diagram of the change in orbital energy level of MBT (a) and DBT (b) under the action of different electric fields in an embodiment;

[0046] Figure 11 Curve diagram of the change in energy gap of MBT (a) and DBT (b) under the action of different electric fields in an embodiment;

[0047] Figure 12 Curve diagram of the density of states of MBT at 0 V / nm in an embodiment;

[0048] Figure 13 Curve diagram of the density of states of DBT at 0 V / nm in an embodiment;

[0049] Figure 14 Curve diagram of the density of states of MBT at 20.41374 V / nm in an embodiment;

[0050] Figure 15A schematic diagram of the density of states of DBT at 13.57488 V / nm in one embodiment;

[0051] Figure 16 A schematic diagram of the spectrum of the infrared spectrum of MBT at 0 V / nm in one embodiment;

[0052] Figure 17 A schematic diagram of the spectrum of the infrared spectrum of DBT at 0 V / nm in one embodiment;

[0053] Figure 18 A schematic diagram of the spectrum of the infrared spectrum of MBT at 20.41374 V / nm in one embodiment;

[0054] Figure 19 A schematic diagram of the spectrum of the infrared spectrum of DBT at 13.57488 V / nm in one embodiment;

[0055] Figure 20 A schematic diagram of the structure of an insulating oil insulation aging state determination apparatus in one embodiment;

[0056] Figure 21 An internal structure diagram of a computer device in one embodiment. DETAILED DESCRIPTION

[0057] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0058] In one embodiment, as shown in Figure 1 , a method for determining the insulation aging state of insulating oil is provided, and the present embodiment takes the method applied to a terminal as an example. It should be understood that the method can also be applied to a server, and can also be applied to a system including a terminal and a server, and is realized through the interaction of the terminal and the server. In the present embodiment, the method includes the following steps:

[0059] In step S202, a single molecule model corresponding to a target molecule in the constituent molecules of the insulating oil is constructed using a molecular simulation tool.

[0060] The insulating oil can refer to a liquid dielectric material in a power capacitor, and can also refer to an insulating medium in other devices or components; the insulating oil includes at least one type of constituent molecule. For example, the insulating oil can include two types of constituent molecules, i.e., monobenzyl toluene (C14H14) and dibenzyl toluene (C21H20).

[0061] Exemplarily, the terminal can determine a target molecule in at least one type of constituent molecule of the insulating oil by using a molecular simulation tool deployed in the terminal, and construct a single-molecule model corresponding to the target molecule.

[0062] In step S204, an extreme electric field strength corresponding to a destruction of the single-molecule model is obtained, and a test electric field strength interval is determined according to the extreme electric field strength.

[0063] The extreme electric field strength can refer to an external electric field strength applied to the single-molecule model when the single-molecule model is destroyed. The electric field strength interval can refer to an interval from zero or a preset electric field strength smaller than the extreme electric field strength to the extreme electric field strength.

[0064] Exemplarily, the terminal obtains the extreme electric field strength corresponding to the destruction of the single-molecule model by simulation test through the molecular simulation tool, and then determines the test electric field strength interval according to the extreme electric field strength.

[0065] In step S206, a dipole moment, a polarizability, an orbital energy level, and a state density of the single-molecule model corresponding to different test electric field strengths in the test electric field strength interval are obtained.

[0066] The dipole moment can be a physical quantity used to describe the distribution of positive and negative charges in a molecule, representing the polarization degree of the molecule in an electric field. The polarizability can refer to the ratio of the electric dipole moment generated by a substance under the action of an external electric field to the applied electric field strength, and can reflect the sensitivity of the molecular polarization behavior. The orbital energy level can be used to describe the discretization state of the electron energy in the molecule, and each molecular orbital has a specific energy value. The state density can be used to describe the number of quantum states available in a certain energy interval, and is usually closely related to the distribution and energy state of the electrons.

[0067] In step S208, a reaction site of the single-molecule model under the extreme electric field strength is determined according to the dipole moment, the polarizability, the orbital energy level, and the state density.

[0068] The reaction site can refer to a specific position in the target molecule that interacts with the external electric field, for example, a specific chemical bond in multiple chemical bonds of the target molecule.

[0069] In step S210, target infrared spectrum information corresponding to the reaction site of the single-molecule model is obtained.

[0070] The target infrared spectrum information is used to match and compare with infrared spectrum information of the insulating oil to be evaluated, so as to obtain an insulation aging state of the insulating oil to be evaluated.

[0071] The target infrared spectrum information of the single-molecule model can be part of the infrared spectrum information corresponding to the reaction site obtained by calculating the single-molecule model by using a preset software tool. The infrared spectrum information of the insulating oil can be obtained by an infrared spectrometer.

[0072] Specifically, the terminal obtains target infrared spectrum information of a single-molecule model corresponding to a reaction site, and the target infrared spectrum information can be used to determine an absorption peak of the reaction site in an infrared spectrum and different frequencies of the absorption peak of the reaction site under different electric field strengths. The terminal further obtains infrared spectrum information of the insulating oil to be evaluated, and matches and finds an absorption peak matching the absorption peak of the reaction site in the infrared spectrum information. The frequency corresponding to the absorption peak can be matched and compared in the target infrared spectrum information to obtain a test electric field strength corresponding to the single-molecule model in the molecular simulation process. The dipole moment, polarizability, orbital energy level, and state density of the single-molecule model corresponding to the test electric field strength are used as performance parameters of a target molecule of the insulating oil to be evaluated, and the insulating aging state of the insulating oil to be evaluated is evaluated according to the performance parameters.

[0073] In the above method for determining the insulating aging state of the insulating oil, the terminal constructs a single-molecule model corresponding to a target molecule of a component molecule of the insulating oil by using a molecular simulation tool. The insulating oil includes at least one type of component molecule. Then, the terminal obtains an extreme electric field strength corresponding to a destruction of the single-molecule model, and determines a test electric field strength interval according to the extreme electric field strength. Next, the terminal obtains the dipole moment, polarizability, orbital energy level, and state density corresponding to different test electric field strengths of the single-molecule model in the test electric field strength interval. Then, the terminal determines a reaction site of the single-molecule model under the extreme electric field strength according to the dipole moment, polarizability, orbital energy level, and state density. Finally, the terminal further obtains target infrared spectrum information of the single-molecule model corresponding to the reaction site. The terminal matches and compares the target infrared spectrum information with infrared spectrum information of the insulating oil to be evaluated to obtain the insulating aging state of the insulating oil to be evaluated. According to the present application, the single-molecule model is constructed, and the electric field response characteristics, i.e., the response changes of the dipole moment, polarizability, orbital energy level, and state density, of the single-molecule model are obtained by molecular simulation. The electric field response characteristics are associated with the infrared spectrum of the reaction site of the single-molecule model. Finally, the infrared spectrum information of the reaction site is matched and compared with the infrared spectrum information of the insulating oil to be evaluated. The change degree of the reaction site in the insulating oil to be evaluated can be evaluated, and the insulating aging state of the insulating oil to be evaluated is obtained. Therefore, only the infrared spectrum information of the insulating oil to be evaluated and the target infrared spectrum information of the reaction site are needed to obtain the insulating aging state, the efficiency of obtaining the insulating aging state is improved, the process of obtaining the insulating aging state is simplified compared with a traditional complex test process, and resource consumption can be reduced. Moreover, the insulating aging state of the insulating oil is determined according to the characteristics of the reaction site at the microscopic molecular level, and the accuracy of evaluating the insulating aging state can be improved.

[0074] In an example embodiment, as shown in Figure 2 The step S202 includes the following steps.

[0075] In step S302, an initial single-molecule model corresponding to the target molecule in the constituent molecules of the insulating oil is constructed by using a molecular simulation tool.

[0076] In step S304, the initial single-molecule model is optimized in structure at the basis set level of PM3 to obtain a single-molecule stable structure at the lowest energy of the molecule.

[0077] In step S306, the single-molecule model corresponding to the single-molecule stable structure is determined as the single-molecule model corresponding to the target molecule.

[0078] The molecular simulation tool can be a computational chemistry software used to simulate the structure and behavior of molecules. Common molecular simulation tools include Gaussian, VASP, LAMMPS, etc., which can predict the properties of molecules in different environments through physical and chemical principles. PM3 (Parameterized Model 3) is a semi-empirical quantum chemistry method used to calculate the electronic structure of molecular systems. Structural optimization can refer to the process of finding the lowest energy point by changing the molecular structure.

[0079] For example, the terminal inputs the atomic type and connection information corresponding to the target molecule in the constituent molecules of the insulating oil by using a molecular simulation tool to construct an initial single-molecule model. The terminal sets the calculation parameters, optimizes the initial single-molecule model in structure at the basis set level of PM3 to obtain a single-molecule stable structure at the lowest energy of the molecule, and determines the single-molecule model corresponding to the single-molecule stable structure as the single-molecule model corresponding to the target molecule.

[0080] In this embodiment, by optimizing the constructed initial single-molecule model in structure at the basis set level of PM3, the single-molecule model corresponding to the single-molecule stable structure at the lowest energy of the molecule is obtained, which can effectively establish and optimize the single-molecule model and provide reliable structural data support for the use of the single-molecule model.

[0081] In an example embodiment, in step S204, the extreme electric field strength corresponding to the destruction of the single-molecule model is obtained by applying an electric field in the direction of the molecular chain to the single-molecule model by using a molecular simulation tool, gradually increasing the electric field strength of the electric field according to a preset electric field strength increment, until the single-molecule model is destroyed, and obtaining the extreme electric field strength corresponding to the destruction of the single-molecule model.

[0082] The electric field applied in the direction of the molecular chain can refer to the direction of the electric field applied being consistent with the main direction of the molecular chain. The direction of the molecular chain generally refers to the orientation of the long-chain structure in the molecule, which can more truly simulate the influence of the electric field on the target molecule. The preset electric field intensity increment can refer to the step-by-step increase of the electric field intensity.

[0083] Exemplarily, the terminal applies an electric field in the direction of the molecular chain to the single-molecule model through a molecular simulation tool, and gradually increases the electric field intensity according to a preset electric field intensity increment, until the single-molecule model is destroyed, to obtain the corresponding extreme electric field intensity when the single-molecule model is destroyed.

[0084] In this embodiment, by applying an electric field with gradually increasing intensity in the direction of the molecular chain of the single-molecule model, the corresponding extreme electric field intensity when the single-molecule model is destroyed can be effectively obtained, and the reliability of the extreme electric field intensity data is improved.

[0085] In an exemplary embodiment, the above step S206 can include the following steps:

[0086] In step S61, the single-molecule model is subjected to molecular simulation corresponding to different test electric field intensities in the test electric field intensity interval by using a quantum chemistry method, to obtain the dipole moment of the single-molecule model corresponding to different test electric field intensities in the molecular simulation process; and the polarization rate corresponding to the single-molecule model is obtained by analyzing the dipole moment.

[0087] In step S62, the orbital energy levels of the single-molecule model corresponding to different test electric field intensities in the test electric field intensity interval are obtained by using a frontier orbital theory through a tool; and the state density of the single-molecule model is obtained according to the orbital energy levels.

[0088] The orbital energy levels include the energy level of the highest occupied molecular orbital and the energy level of the lowest unoccupied molecular orbital. The quantum chemistry method can refer to a series of theories and calculation tools for calculating and predicting the behavior of molecules.

[0089] Exemplarily, the terminal applies an electric field intensity cyclically through calculation software, covering the preset test electric field intensity interval, and then subjects the single-molecule model to molecular simulation corresponding to different test electric field intensities in the test electric field intensity interval by using a quantum chemistry method, to obtain the dipole moment of the single-molecule model corresponding to different test electric field intensities in the molecular simulation process; and the polarization rate corresponding to the single-molecule model is obtained by analyzing and calculating the dipole moment; then the terminal calculates the electronic state of the single-molecule model at different test electric field intensities by using a frontier orbital theory through a tool, and records the energy level values of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO); and then the terminal can obtain the state density of the single-molecule model based on the obtained orbital energy levels by using a state density formula.

[0090] In this embodiment, by obtaining the dipole moment and the polarizability, the electrical performance of the target molecule in the electric field can be understood in depth; by obtaining the polarizability and the relationship between the polarizability and the electric field intensity, the electrical characteristics of the target molecule under actual operating conditions can be evaluated; by calculating the orbital energy level and the state density, the energy gap and the electron transfer properties can be accurately predicted, and through the above steps, the changes in the physical and chemical properties of the insulating oil under different electric field intensities can be more accurately understood, so that the insulation aging state of the insulating oil can be more accurately evaluated.

[0091] In an exemplary embodiment, the above step S61 can specifically include the steps of: obtaining, by using a quantum chemistry method, a first Hamiltonian of the single-molecule model under no applied electric field, and obtaining a second Hamiltonian of the single-molecule model corresponding to different test electric field intensities in a test electric field intensity interval; and obtaining a dipole moment corresponding to the single-molecule model under the test electric field intensity according to the first Hamiltonian, the second Hamiltonian, and the test electric field intensities corresponding to the second Hamiltonian.

[0092] The Hamiltonian can refer to an operator in quantum mechanics for describing the energy of a system, including the kinetic energy and potential energy of the system.

[0093] Exemplarily, the terminal obtains, by using a quantum chemistry method, a first Hamiltonian of the single-molecule model under no applied electric field, and obtains a second Hamiltonian of the single-molecule model corresponding to different test electric field intensities in a test electric field intensity interval; and obtains a dipole moment corresponding to the single-molecule model under the test electric field intensity according to the first Hamiltonian, the second Hamiltonian, and the test electric field intensities corresponding to the second Hamiltonian. The dipole moment can be obtained according to the formula H int =-µ×F, H int represents the influence of the electric field intensity on the single-molecule model, i.e., the Hamiltonian (second Hamiltonian) when an external electric field exists applied to the single-molecule model, µ represents the dipole moment of the single-molecule model, and F represents the size of the test electric field intensity (the test electric field intensity corresponding to the second Hamiltonian); the Hamiltonian H of the single-molecule model can be represented by H=H0+H int , H0 represents the Hamiltonian (first Hamiltonian) corresponding to the single-molecule model when there is no external electric field.

[0094] In this embodiment, by using a quantum chemistry method, the behavior of the single-molecule model under different electric field intensities can be accurately simulated, and by molecular-level molecular simulation, the aging state of the insulating oil under different electric field intensities can be more accurately evaluated. Compared with actual experimental tests, molecular simulation can reduce a large amount of time and material resource consumption, and reduce resource consumption for evaluation.

[0095] In an exemplary embodiment, in step S62, the state density of the single molecule model is obtained according to the orbital energy level, including the steps of: obtaining the energy gap of the single molecule model in the test electric field intensity interval according to the energy level of the highest occupied molecular orbital and the energy level of the lowest unoccupied molecular orbital; and obtaining the state density of the single molecule model according to the orbital energy level and the energy gap.

[0096] By understanding the state density and the energy gap, the electronic structure, the electron transfer ability and the interaction with the external electric field of the molecule can be understood in depth.

[0097] Exemplarily, all molecular orbital energy levels of the molecule model are obtained through quantum chemical calculation (such as DFT or HF method), including the energy level of the highest occupied molecular orbital (HOMO) and the energy level of the lowest unoccupied molecular orbital (LUMO). The energy values of HOMO and LUMO are extracted from the obtained orbital energy levels, the difference value is calculated to obtain the energy gap, and the state density is constructed using the orbital energy level information and the energy gap. The state density can be obtained by visualizing the molecular orbital energy level distribution to detect the state density in a specific energy range. The state density distribution in different energy regions is estimated by numerical methods (such as Gaussian smoothing). The above steps are repeated under different test electric field intensities, and the state densities under different conditions are counted.

[0098] In this embodiment, by understanding the state density and the energy gap, the electronic structure, the electron transfer ability and the interaction with the external electric field of the molecule can be understood in depth. By accurately calculating the orbital energy level and the state density, the aging state of the insulating oil under different electric field intensities can be more accurately evaluated, and the accuracy of the evaluation is improved.

[0099] In another exemplary embodiment, a method for determining the insulating aging state of insulating oil is provided, specifically comprising:

[0100] In step S1, a single molecule model of benzyltoluene (C14H14, MBT) and dibenzyltoluene (C21H20, DBT) is constructed by using a molecular simulation software; wherein the target molecule of the insulating oil can be benzyltoluene (C14H14, MBT) and dibenzyltoluene (C21H20, DBT). In step S1, the single molecule model is optimized at the PM3 basis set level to obtain the stable structure with the lowest molecular energy.

[0101] In step S2, an external electric field is established, and the intensity of the external electric field is gradually increased in the molecule model until the molecule model is destroyed.

[0102] Step S3, dipole moment and polarizability calculation, using quantum chemistry method to carry out molecular simulation on the capacitor insulating oil under different applied electric field intensity, through the software built-in command to calculate the microstructure characteristics of the molecular model, get the dipole moment and polarizability under different applied electric field intensity. In step S3, according to the dipole approximation, when there is no external electric field, the corresponding Hamiltonian is denoted as H0. Subsequently, after the application of electric field, the Hamiltonian H of the molecular system can be expressed as H=H0+Hint. Hint item represents the Hamiltonian when the external electric field exists on the molecular system. When interacting with the molecular system, Hint=-µ×F represents the influence of electric field intensity on it, wherein µ represents the electric dipole moment of the molecule, F represents the size of the electric field, the dipole moment and the polarizability under different applied electric field intensity are calculated.

[0103] Step S4, molecular orbital analysis, using software to calculate the characteristics of orbital energy level and state density under different applied electric field intensity, and combining the dipole moment and polarizability parameters of step S3, to predict the reaction site of the capacitor insulating oil under extreme electric field intensity.

[0104] Step S5, establish macro-micro correlation model, calculate the infrared spectrum of the capacitor insulating oil before and after the breakdown of the applied electric field by software, and establish the state evaluation model of the capacitor insulating oil electrical aging through the difference of infrared spectrum before and after the breakdown. In step S5, the infrared spectrum of the capacitor insulating oil under different applied electric field is calculated, and the correlation between the electrical aging state of the capacitor insulating oil and the infrared spectrum is established.

[0105] Specifically, first, the PM3 basis set based on the semi-empirical method is used to optimize the geometric configuration of the capacitor insulating oil molecular model, and the lowest energy molecular stable conformation is obtained. The optimized molecular model is shown in Figure 3 and Figure 4 , the structure diagram of the molecular model of MBT is shown in Figure 3 , the structure diagram of the molecular model of DBT is shown in Figure 4 , wherein the gray represents the carbon atom C, the white represents the hydrogen atom h, the total energy is the lowest, there is no virtual frequency, and the criteria Maximum Force, RMS Force, Maximum Displacement, RMS Displacement are all converged.

[0106] The same method and base are used to apply electric dipole field in the X direction of the molecular chain, and the geometric mechanism is optimized. The geometric structure parameters, single point energy, dipole moment, polarizability, molecular orbital energy gap, state density and infrared spectrum of the insulating material are predicted.

[0107] The length of the chemical bond in the molecule under the action of the external electric field is calculated to change accordingly, as shown in Figure 5As shown, the curve diagram of the bond length change of MBT (a) and DBT (b) molecules is provided, thereby characterizing the change of the molecular geometry caused by the electric field. In the molecular system, the positive and negative charges are affected by the external electric field, producing mutual transmission effect, resulting in a certain degree of elongation of the insulating oil molecules, reducing the stability of its internal geometry. When the strength of the external electric field reaches a certain threshold, the insulating oil molecules are significantly elongated due to the action of the external electric field, resulting in rapid deterioration of the insulating performance, approaching the critical level, i.e. about to break down, in combination Figure 3 and Figure 6 It can be seen from the comparison that, Figure 6 the structure contained in the red circle in the MBT molecule model is significantly elongated, and the molecular bond rupture change occurs; in combination Figure 4 and Figure 7 It can be seen from the comparison that, Figure 7 the structure contained in the red circle in the DBT molecule model is significantly elongated, and the molecular bond rupture change occurs.

[0108] The molecular dipole moment and polarizability under the action of the external electric field are calculated. With the gradual increase of the electric field intensity, the total energy of the MBT / DBT molecule shows a downward trend, as shown in Figure 8 and Figure 9 where Total Energy represents the total energy of the molecule, Dipole Moment represents the dipole moment, and Polarizability represents the polarizability. Under the influence of the electric field, the electrons migrate to the direction, resulting in an increase in the charge on each atom, as well as an increase in the dipole moment and polarizability within the MBT / DBT molecule. When reaching the critical value, both the dipole moment and the polarizability increase sharply, indicating that the structure state is highly unstable. Long-term exposure to the external electric field, the stability of the molecular system within the MBT / DBT insulating oil gradually weakens. When the upper limit of the dipole moment is exceeded, it exceeds the critical value, resulting in the escape of free electrons from the atomic nucleus.

[0109] The orbital energy level and energy gap (Eg) of the MBT / DBT molecule are calculated by Gaussian software, reflecting the electronic motion characteristics of the MBT / DBT molecule under different external electric fields. The applied electric field makes the LUMO energy level of the MBT / DBT molecule gradually decrease, and the HOMO energy level gradually increase, thereby changing the reaction activity characteristics of the MBT / DBT molecule. At the same time, the HOMO and LUMO orbital energy levels of the two molecules are relatively close, the Eg value of the MBT molecule is 3.28 eV, and the Eg value of the DBT molecule is 1.33 eV, as shown in Figure 10 and Figure 11The horizontal axis is the electric field intensity (V / nm). The breakdown of the MBT / DBT molecule occurs due to the free shuttling of electrons between the valence band and the conduction band, resulting in the generation of current and the destruction of the insulating properties of the MBT / DBT insulating oil.

[0110] The state density was calculated using the Multiwfn software. The HOMO orbital energy corresponds to the highest level of the valence band, while the LUMO orbital energy corresponds to the lowest energy level of the conduction band. Under an external electric field, the state density diagram predicts that the deep trap level distribution appears near the upper edge of the valence band, while the shallow trap level distribution appears near the lower edge of the conduction band, as shown in Figure 12 and Figure 13 , where Density of State represents the state density, and Energy Level represents the energy level, with units of eV (electron volts). With the application of an external electric field, the capture energy density of the molecular orbit gradually increases. The energy distribution of the highest occupied molecular orbital (HOMO) moves to a higher position, resulting in an increase in the number of hole traps near the valence band. Conversely, the energy distribution of the lowest unoccupied molecular orbital (LUMO) moves to a lower position, resulting in an increase in the number of electron traps near the conduction band. Ultimately, there is a significant difference between the number of electron and hole traps, as shown in Figure 14 and Figure 15 , Figure 14 is a curve diagram of the state density of MBT when the external electric field intensity is 20.41374 V / nm, Figure 15 is a curve diagram of the state density of DBT when the external electric field intensity is 13.57488 V / nm. This difference makes it easier for MBT / DBT materials to capture free electrons or inject charges.

[0111] Further processing of the calculation results was performed using the Multiwfn software, resulting in infrared spectrum data under zero external electric field intensity and breakdown field intensity, as shown in Figure 16 , Figure 17 , Figure 18 , Figure 19The molar absorption coefficient (Molar Absorption Coefficient), usually represented by the symbol ε, is a physical quantity used to describe the absorption capacity of a certain substance to light at a specific wavelength; Frequency (cm-1) represents frequency. With the increase of the applied electric field, the absorption peaks of MBT and DBT molecules above 3000 cm-1 appear red shift, due to the increase of bond length, the decrease of bond energy. With the increase of the applied electric field, the peak value also increases. The C25-H28, C11-C13, C11-H14 bond of MBT molecule and the C38-H41 bond of DBT molecule appear obvious red shift, indicating that they have strong instability before the chemical bond breaks, which is consistent with the geometric structure analysis. Therefore, the changes of infrared spectrum before and after breakdown can provide a feasible reference for detecting the aging state of MBT / DBT insulating oil.

[0112] In this embodiment, computer molecular simulation experiment is used to simulate and predict the electrical properties of capacitor insulating oil from the microscale. The model is not affected by the precision of the instrument and human factors, and can simulate the physical and chemical and electrical properties such as molecular structure change, dipole moment, polarizability, molecular orbital energy level, energy gap, state density, infrared spectrum, etc. The predicted infrared spectrum has reliability with the breakdown of insulating materials. The most important feature is that the model effectively links the microstructure change with the infrared spectrum. It can predict the weak molecular chemical bonds of capacitor insulating oil under extreme electric field, and provide site reference for capacitor insulating oil material modification. At the same time, the change trend of infrared spectrum can be used as a theoretical basis for insulating state evaluation.

[0113] It should be understood that although each step in the flowchart involved in each embodiment as described above is shown in sequence according to the direction of the arrow, these steps are not necessarily executed in sequence according to the direction of the arrow. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other sequences. Moreover, at least part of the steps in the flowchart involved in each embodiment as described above can include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of these steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least part of other steps or steps or stages in other steps.

[0114] Based on the same inventive concept, the application further provides an insulation oil insulation aging state determination device for implementing the above-mentioned insulation oil insulation aging state determination method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more insulation oil insulation aging state determination device embodiments provided below can refer to the limitations of the insulation oil insulation aging state determination method described above, which will not be repeated here.

[0115] In one exemplary embodiment, as shown in Figure 20 An insulation oil insulation aging state determination device 900 is provided, comprising a molecular model construction module 901, a model data acquisition module 902, a reaction site determination module 903, and an infrared spectrum acquisition module 904, wherein:

[0116] The molecular model construction module 901 is configured to construct a single-molecule model corresponding to a target molecule in a component molecule of the insulation oil by using a molecular simulation tool; the insulation oil comprises at least one type of component molecule;

[0117] The model data acquisition module 902 is configured to acquire an extreme electric field strength corresponding to a destruction of the single-molecule model, and determine a test electric field strength interval according to the extreme electric field strength; and further configured to acquire a dipole moment, a polarizability, an orbital energy level, and a state density corresponding to different test electric field strengths in the test electric field strength interval;

[0118] The reaction site determination module 903 is configured to determine a reaction site of the single-molecule model under the extreme electric field strength according to the dipole moment, the polarizability, the orbital energy level, and the state density;

[0119] The infrared spectrum acquisition module 904 is configured to acquire target infrared spectrum information corresponding to the reaction site of the single-molecule model; the target infrared spectrum information is used for matching and comparison with infrared spectrum information of the insulation oil to be evaluated, so as to obtain an insulation aging state of the insulation oil to be evaluated.

[0120] In one exemplary embodiment, the above-mentioned molecular model construction module 901 is further configured to construct an initial single-molecule model corresponding to a target molecule in a component molecule of the insulation oil by using a molecular simulation tool; to perform structural optimization on the initial single-molecule model at a PM3 basis set level to obtain a single-molecule stable structure at a lowest molecular energy; and to determine a single-molecule model corresponding to the single-molecule stable structure as the single-molecule model corresponding to the target molecule.

[0121] In one exemplary embodiment, the above-mentioned model data acquisition module 902 is further configured to apply an electric field in a molecular chain direction to the single-molecule model by using a molecular simulation tool, and gradually increase the electric field strength of the electric field according to a preset electric field strength increment, until the single-molecule model is destroyed, to acquire an extreme electric field strength corresponding to the destruction of the single-molecule model.

[0122] In an example embodiment, the model data obtaining module 902 is further configured to obtain, by using a quantum chemistry method, dipole moments of the single-molecule model corresponding to different test electric field strengths in a test electric field strength interval by performing molecular simulation on the single-molecule model corresponding to the different test electric field strengths; obtain a polarizability corresponding to the single-molecule model by analyzing the dipole moments; obtain orbital energy levels of the single-molecule model corresponding to the different test electric field strengths in the test electric field strength interval by using a frontier orbital theory and a tool; and obtain a state density of the single-molecule model according to the orbital energy levels, wherein the orbital energy levels include an energy level of a highest occupied molecular orbital and an energy level of a lowest unoccupied molecular orbital.

[0123] In an example embodiment, the model data obtaining module 902 is further configured to obtain, by using a quantum chemistry method, a first Hamiltonian of the single-molecule model under a condition that no electric field is applied, and a second Hamiltonian of the single-molecule model corresponding to different test electric field strengths in a test electric field strength interval; and obtain a dipole moment corresponding to the single-molecule model under the test electric field strength according to the first Hamiltonian, the second Hamiltonian, and the test electric field strengths corresponding to the second Hamiltonian.

[0124] In an example embodiment, the model data obtaining module 902 is further configured to obtain, according to the energy level of the highest occupied molecular orbital and the energy level of the lowest unoccupied molecular orbital, a band gap corresponding to the single-molecule model in the test electric field strength interval; and obtain a state density of the single-molecule model according to the orbital energy levels and the band gap.

[0125] The modules in the insulating oil insulation aging state determination apparatus can be implemented by software, hardware, or a combination thereof. The modules can be embedded in or independent of a processor in a computer device in a hardware form, or stored in a memory in the computer device in a software form, so as to be called and executed by the processor.

[0126] In an example embodiment, a computer device is provided, which can be a terminal. An internal structure diagram of the computer device can be as shown in FIG. 8. Figure 21The computer device shown in the figure includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capability. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operating system and the computer program in the non-volatile storage medium to run. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals in a wired or wireless manner. The wireless manner can be realized through WIFI, mobile cellular network, near field communication (NFC) or other technologies. The computer program is executed by the processor to realize an insulation oil insulation aging state determination method. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device can be a touch layer overlaid on the display screen, or a key, trackball or touchpad arranged on the shell of the computer device, or an external keyboard, touchpad or mouse, etc.

[0127] Those skilled in the art can understand that, Figure 21 The structure shown in the figure is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0128] In one embodiment, a computer device is also provided, including a memory and a processor, the memory storing a computer program, and the processor executing the computer program to realize the steps in each of the above method embodiments.

[0129] In one embodiment, a computer readable storage medium is provided, which stores a computer program, and the computer program is executed by a processor to realize the steps in each of the above method embodiments.

[0130] In one embodiment, a computer program product is provided, including a computer program, and the computer program is executed by a processor to realize the steps in each of the above method embodiments.

[0131] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned embodiment methods. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. The non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. The volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, the RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., without being limited thereto.

[0132] The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0133] The above-described embodiments are merely illustrative of several embodiments of the present application, and the description is relatively specific and detailed, but should not be understood as a limitation on the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A method for determining the insulation aging state of an insulating oil, characterized by, The method comprises: a single molecule model corresponding to a target molecule in a component molecule of insulating oil is constructed by using a molecular simulation tool; the insulating oil comprises at least one kind of component molecule; extreme electric field strength corresponding to destruction of the single molecule model is obtained, and a test electric field strength interval is determined according to the extreme electric field strength; dipole moment, polarizability, orbital energy level and state density corresponding to different test electric field strengths in the test electric field strength interval are obtained for the single molecule model; a reaction site of the single molecule model under the extreme electric field strength is determined according to the dipole moment, the polarizability, the orbital energy level and the state density; target infrared spectrum information corresponding to the reaction site of the single molecule model is obtained; the target infrared spectrum information is used for matching and comparison with infrared spectrum information of insulating oil to be evaluated, so as to obtain an insulating aging state of the insulating oil to be evaluated.

2. The method of claim 1, wherein, The single molecule model corresponding to the target molecule in the component molecule of the insulating oil is constructed by using the molecular simulation tool, comprising: an initial single molecule model corresponding to the target molecule in the component molecule of the insulating oil is constructed by using the molecular simulation tool; the initial single molecule model is subjected to structure optimization at a PM3 basis group level to obtain a single molecule stable structure at a lowest molecular energy; the single molecule model corresponding to the single molecule stable structure is determined as the single molecule model corresponding to the target molecule.

3. The method of claim 2, wherein, The extreme electric field strength corresponding to the destruction of the single molecule model is obtained, comprising: an electric field in a molecular chain direction is applied to the single molecule model by using the molecular simulation tool, and the electric field strength of the electric field is gradually increased according to a preset electric field strength increment, until the single molecule model is destroyed, so as to obtain the extreme electric field strength corresponding to the destruction of the single molecule model.

4. The method of claim 1, wherein, The dipole moment, the polarizability, the orbital energy level and the state density corresponding to different test electric field strengths in the test electric field strength interval are obtained for the single molecule model, comprising: a quantum chemistry method is used to perform molecular simulation on the single molecule model corresponding to different test electric field strengths in the test electric field strength interval, to obtain the dipole moment of the single molecule model corresponding to different test electric field strengths in the molecular simulation process; the polarizability corresponding to the single molecule model is obtained according to the dipole moment; an orbital energy level corresponding to different test electric field strengths in the test electric field strength interval is obtained for the single molecule model by using a frontier orbital theory and a tool; the state density of the single molecule model is obtained according to the orbital energy level; wherein, the orbital energy level comprises an energy level of a highest occupied molecular orbital and an energy level of a lowest unoccupied molecular orbital.

5. The method of claim 4, wherein, The quantum chemistry method is used to perform molecular simulation on the single molecule model corresponding to different test electric field strengths in the test electric field strength interval, to obtain the dipole moment of the single molecule model corresponding to different test electric field strengths in the molecular simulation process, comprising: a first Hamiltonian of the single molecule model under a condition of no applied electric field is obtained by using a quantum chemistry method, and a second Hamiltonian of the single molecule model corresponding to different test electric field strengths in the test electric field strength interval is obtained; According to the first Hamiltonian, the second Hamiltonian and the test electric field strength corresponding to the second Hamiltonian, a dipole moment corresponding to the single-molecule model under the test electric field strength is obtained.

6. The method of claim 4, wherein, The state density of the single-molecule model is obtained according to the orbital energy level, and the state density of the single-molecule model is obtained according to the orbital energy level and the energy gap. According to the energy level of the highest occupied molecular orbital and the energy level of the lowest unoccupied molecular orbital, an energy gap corresponding to the single-molecule model in the test electric field strength interval is obtained. According to the orbital energy level and the energy gap, the state density of the single-molecule model is obtained.

7. An insulating oil insulation aging state determination device characterized by comprising: The device comprises: A molecular model construction module is configured to construct a single-molecule model corresponding to a target molecule in a component molecule of insulating oil by using a molecular simulation tool; the insulating oil comprises at least one type of component molecule; A model data acquisition module is configured to acquire an extreme electric field strength corresponding to a destruction of the single-molecule model, and determine a test electric field strength interval according to the extreme electric field strength; and further configured to acquire a dipole moment, a polarizability, an orbital energy level and a state density corresponding to different test electric field strengths in the test electric field strength interval; A reaction site determination module is configured to determine a reaction site of the single-molecule model under the extreme electric field strength according to the dipole moment, the polarizability, the orbital energy level and the state density; An infrared spectrum acquisition module is configured to acquire target infrared spectrum information corresponding to the reaction site of the single-molecule model; the target infrared spectrum information is used for matching and comparison with infrared spectrum information of a to-be-evaluated insulating oil, so as to obtain an insulation aging state of the to-be-evaluated insulating oil.

8. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that, The processor executes the computer program to realize the steps of the method of any one of claims 1 to 6.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to realize the steps of the method of any one of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to realize the steps of the method of any one of claims 1 to 6. The computer program is executed by the processor to realize the steps of the method of any one of claims 1 to 6.

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