Method for predicting electrical properties of epoxy resin-based insulators
By constructing a single-molecular model of epoxy resin-based insulating materials and combining molecular simulation and infrared spectroscopy technology, the problem that the existing technology cannot accurately predict the electrical properties of epoxy resin insulators is solved, and the accurate prediction of the electrical properties of insulators under different electric fields is achieved, providing a new theoretical basis and data support for the state evaluation and aging mechanism research of epoxy insulators.
Patent Information
- Application Number
- CN202411501710.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-25
- Publication Date
- 2025-02-25
AI Technical Summary
Existing detection methods cannot accurately predict the long-term electrical properties of epoxy resin-based insulators under specific electric fields, and cannot achieve online monitoring and real-time evaluation.
By constructing a single-molecular model of epoxy resin-based insulating material, using molecular simulation and infrared spectroscopy technology, the behavior under the applied electric field is simulated, the dipole moment and polarization rate are calculated, the molecular orbitals are analyzed, and the macro-micro-correlation model is established to predict the electrical properties of insulators under different electric fields.
The accurate prediction of the electrical properties of epoxy resin insulators under different electric fields is achieved, and new theoretical basis and data support is provided, providing new methods for the state evaluation and aging mechanism research of epoxy insulators.
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Abstract
Description
Technical Field
[0001] The present application relates to the technical field of epoxy resin insulating materials, and in particular to a method for predicting the electrical properties of epoxy resin-based insulators. Background Art
[0002] Epoxy resin-based insulation materials have become the preferred material for manufacturing 500kV GIS insulators due to their excellent insulation performance, mechanical strength and chemical corrosion resistance. However, during long-term operation, this type of insulation material will be affected by factors such as electric field, temperature, humidity and chemical media, and the material performance will gradually degrade, which may eventually cause insulation failure and affect the safe and stable operation of the power system.
[0003] At present, the main methods for testing the insulation performance of 500kV GIS insulators are insulation resistance measurement, AC withstand voltage, etc. Although the above tests can provide certain information, they often cannot accurately predict the long-term behavior of materials under specific electric fields, nor can they reveal the microscopic mechanism of material aging. In addition, these methods usually require destructive testing and cannot achieve online monitoring and real-time evaluation.
[0004] In recent years, with the development of computational chemistry and molecular simulation technology, attempts have been made to predict the macroscopic properties of materials from a microscopic perspective by building molecular models. This method can provide more in-depth information on the internal structure and dynamic behavior of materials, and help understand the mechanism of microscopic changes in material aging. However, existing molecular simulation methods still have some limitations in predicting the electrical properties of epoxy insulators, such as insufficient model accuracy, low computational efficiency, and weak correlation with experimental data. Summary of the invention
[0005] The purpose of this application is to provide a method for predicting the electrical properties of epoxy resin-based insulators, which uses molecular simulation and infrared spectroscopy technology to effectively predict the electrical properties of epoxy resin insulator materials under different electric fields; the method is easy to operate and low in cost, and can be applied to the state, performance evaluation and prediction of 500kVGIS insulator materials, providing a new theoretical basis and data support for the state evaluation and aging mechanism research of epoxy insulators.
[0006] The technical solution of this application is as follows:
[0007] On the one hand, an embodiment of the present application provides a method for predicting electrical properties of epoxy resin-based insulators, which comprises the following steps:
[0008] S1: Construct a single molecule model of epoxy resin-based insulating materials, use molecular simulation software to optimize the structure, and obtain a stable structure with the lowest molecular energy;
[0009] S2: Apply an external electric field in the X-axis direction of the molecular chain to calculate the physical quantity data of the epoxy resin molecules in the initial state and the breakdown state;
[0010] S3: Analyze the physical quantity data of epoxy resin molecules in the initial state and the breakdown state, calculate the changes in the dipole moment and polarizability of epoxy resin molecules under the action of an external electric field, and evaluate the stability of the epoxy resin molecular system;
[0011] S4: Calculate the orbital energy level, energy gap and state density of epoxy resin molecules, and analyze the influence of external electric field on the electronic motion characteristics of epoxy resin molecules;
[0012] S5: Analyze and process the calculation results of step S4 to obtain infrared spectrum data of epoxy resin molecules in different states, and establish a correlation between the electrical aging state of epoxy resin-based insulators and the infrared spectrum through the difference in infrared spectra, so as to realize the evaluation of the electrical aging state of epoxy resin-based insulators.
[0013] Furthermore, in some embodiments of the present application, in the above step S1, a single molecule model of an epoxy resin-based insulating material is constructed, and its structural formula is as follows:
[0014]
[0015] Furthermore, in some embodiments of the present application, in the above-mentioned step S1, the geometric configuration of the single-molecule model of the constructed epoxy resin-based insulating material is optimized using the PM3 basis set based on the semi-empirical method to obtain a stable structure with the lowest molecular energy, so that the molecular geometric configuration is neutral in the lowest energy state and has a singlet charge and spin state; the unrestricted Kohn-Sham method is used for calculation.
[0016] Furthermore, in some embodiments of the present application, in the above-mentioned step S2, the applied external electric field is an electric dipole field; the initial state of the epoxy resin molecule is the state when the applied electric dipole field is 0, and the breakdown state of the epoxy resin molecule is the state when the molecular geometric structure is calculated to have changed significantly by applying the electric dipole field using the trial and error method.
[0017] Further, in some embodiments of the present application, in the above step S2, the physical quantity data of the epoxy resin molecule in the initial state includes geometric configuration, dipole moment, polarizability, state density, energy gap distribution, molecular orbital and infrared spectrum;
[0018] The physical quantity data of epoxy resin molecules in the breakdown state include geometric configuration, state density, energy gap distribution, molecular orbital and infrared spectrum.
[0019] Furthermore, in some embodiments of the present application, in the above step S4, the molecular orbital energy levels are calculated using Gaussian software, and the energy gap and state density are calculated using Multiwfn software.
[0020] Furthermore, in some embodiments of the present application, in the above step S5, the calculation results are analyzed and processed using Multiwfn software.
[0021] On the other hand, an embodiment of the present application also provides an application of the above method to the material status, performance evaluation and prediction of 500kV GIS insulators.
[0022] Compared with the prior art, the embodiments of the present application have at least the following advantages or beneficial effects:
[0023] In view of the above aspects, the embodiment of the present application provides a method for predicting the electrical properties of epoxy resin-based insulators, and the application of the method in the state, performance evaluation and prediction of 500kVGIS insulator materials. The method constructs a molecular model of epoxy resin-based insulating materials and optimizes its structure, simulates the behavior under an applied electric field, calculates the dipole moment and polarizability, analyzes molecular orbitals, and establishes a macro-micro correlation model, and uses molecular simulation and infrared spectroscopy technology to predict the electrical properties of insulators under different electric fields. With the help of computer tools, molecular simulation experiments are carried out to simulate and predict the electrical properties of epoxy insulators from a microscopic scale, thereby avoiding the limitations of instrument accuracy and human factors; at the same time, the microstructural changes are effectively linked to the infrared spectrum, providing a site reference for the modification of epoxy insulator materials; the scheme has high reliability, is easy to operate, and can more accurately evaluate and predict material performance. It is applied to 500kVGIS insulator materials and can effectively provide a new theoretical basis and data support for its state evaluation and aging mechanism research. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.
[0025] Figure 1 This is a schematic diagram of the geometric structure of the epoxy resin molecule in the initial state in the embodiment of the present application;
[0026] Figure 2 A schematic diagram of the geometric structure of an epoxy resin molecule in a punctured state in an embodiment of the present application;
[0027] Figure 3This is the highest occupied molecular orbital (HOMO) diagram of epoxy resin molecules at 6.68 kV / mm in the embodiment of the present application;
[0028] Figure 4 This is the lowest unoccupied molecular orbital (LUMO) diagram of epoxy resin molecules at 6.68 kV / mm in the embodiment of the present application;
[0029] Figure 5 This is a distribution diagram of the molecular state density of epoxy resin in the embodiment of this application;
[0030] Figure 6 This is a distribution diagram of energy state changes of epoxy resin molecules in the embodiment of the present application;
[0031] Figure 7 Infrared spectrum of epoxy resin molecules in the breakdown state in the embodiment of the present application;
[0032] Figure 8 This is a comparison diagram of infrared spectra of epoxy resin molecules before and after an external electric field is applied in the embodiment of the present application. DETAILED DESCRIPTION
[0033] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.
[0034] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "includes..." do not exclude the existence of other identical elements in the process, method, article or device including its elements.
[0035] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.
[0036] The features and performance of the present application are further described in detail below in conjunction with the embodiments.
[0037] Example
[0038] The present invention provides a method for predicting the electrical properties of epoxy resin-based insulators, which comprises the following steps:
[0039] S1: Construct a single molecule model of epoxy resin-based insulating material, the structural formula of which is as follows:
[0040]
[0041] The PM3 basis set based on the semi-empirical method is used to optimize the geometric configuration of the constructed single-molecule model of epoxy resin-based insulating materials to obtain the stable structure with the lowest molecular energy, so that the molecular geometry is neutral at the lowest energy state and has a single charge and spin state; the unrestricted Kohn-Sham method is used for calculation. This step is the key to the overall accuracy of the scheme, which involves accurate simulation of the molecular structure of epoxy resin-based insulating materials and is a prerequisite for predicting their electrical properties.
[0042] The geometric structure of the epoxy resin molecule after optimization is as follows: Figure 1 As shown;
[0043] S2: An electric dipole field is applied in the X direction of the molecular chain, and the electric field strength is gradually increased at a certain rate to simulate the molecular behavior of the epoxy insulation sleeve under different electric field strengths.
[0044] Among them, in the stage where the electric field has not been applied (when the applied electric dipole field is 0), the state of the epoxy resin molecules is the initial state (such as Figure 1 As shown in the figure), all the corresponding physical quantities in this state (including geometric configuration, dipole moment, polarizability, state density, energy gap distribution, molecular orbital and infrared spectrum) are the physical quantities when the epoxy resin molecules are in a good state.
[0045] After applying the electric dipole field, the electric field strength is gradually increased by trial and error. When the molecular geometry changes significantly, the epoxy resin molecule is in a breakdown state (the geometric structure of the epoxy resin molecule in the breakdown state is as follows: Figure 2 In this state, all corresponding physical quantities (including geometric configuration, state density, energy gap distribution, molecular orbital and infrared spectrum) are the physical quantities when the epoxy resin molecule is in a breakdown state.
[0046] S3: Analyze the physical quantity data of the epoxy resin molecules in the initial state and the breakdown state obtained in step S2, calculate the changes in the dipole moment and polarizability of the epoxy resin molecules under the action of an external electric field, and comprehensively evaluate the stability of the epoxy resin molecular system through geometric configuration, state density, energy gap distribution, molecular orbital and infrared spectrum.
[0047] The core of steps S2 and S3 is to be able to gradually observe and analyze the response of insulating materials under the action of electric fields, including molecular polarization, charge distribution changes, etc., which is crucial to understanding the performance of materials under actual working conditions. Using quantum chemical methods, the microstructural characteristics of the molecular model are calculated through the built-in commands of the software to obtain the dipole moment and polarizability under different external electric field strengths. These parameters are important indicators for evaluating the behavior of materials in electric fields, and they are directly related to the dielectric properties and breakdown strength of the materials.
[0048] S4: Gaussian software was used to calculate the energy levels of the highest occupied molecular orbital and the lowest unoccupied molecular orbital, and Multiwfn software was used to calculate the energy gap and state density parameters. The effect of the external electric field on the motion characteristics of molecular electrons was analyzed. These analyses help predict the reaction sites of epoxy insulators under extreme electric fields, that is, the locations where chemical changes or breakdown may occur in the material.
[0049] Specifically, when the energy gap value is lower than 2eV, it is considered as insulation failure; when the energy gap value is between 2 and 6eV, the insulation is considered to be in an aged state and is not suitable for continued use. The change in the LUMO value in the initial state and the breakdown state is set as an electron trap. The larger the electron trap value, the stronger the ability of the epoxy resin to obtain electrons under the action of an external electric field. The change in the HOMO value in the initial state and the breakdown state is set as a hole trap. The larger the hole trap value, the stronger its ability to lose electrons. The changes in HOMO and LUMO can explain the mechanism of changes in the electrical properties of epoxy resin molecules.
[0050] Among them, the highest occupied molecular orbital (HOMO) of the epoxy resin molecule at 6.68 kV / mm is as follows: Figure 3 As shown; the lowest unoccupied molecular orbital (LUMO) of the epoxy resin molecule at 6.68kV / mm is as follows Figure 4 As shown; the state density distribution of epoxy resin molecules is as follows Figure 5 As shown; the energy state change distribution of epoxy resin molecules is as follows Figure 6 shown.
[0051] exist Figure 5 In the figure, the red dotted line represents the HOMO orbital characteristics of the epoxy molecule in the initial state, and the red solid line represents the HOMO orbital characteristics of the epoxy molecule in the breakdown state; the blue dotted line represents the LUMO orbital characteristics of the epoxy molecule in the initial state, and the blue solid line represents the LUMO orbital characteristics of the epoxy molecule in the second state.
[0052] S5: Analyze and process the calculation results of step S4 to obtain infrared spectrum data of epoxy resin molecules in different states, and establish the correlation between the electrical aging state of epoxy resin-based insulators and infrared spectrum through the difference of infrared spectrum, so as to realize the evaluation of the electrical aging state of epoxy resin-based insulators. The purpose of this step is to link the microstructure changes with the macroscopic observable spectral characteristics, thereby providing a new technical means for the state monitoring and life prediction of epoxy insulators.
[0053] Among them, the infrared spectrum of epoxy resin molecules in the breakdown state is as follows Figure 7 As shown in the figure, the infrared spectra of epoxy resin molecules before and after the external electric field is applied are compared. Figure 8 shown.
[0054] It can be seen that at about 800cm -1 and 1500cm -1 Two obvious peaks were observed at 700 cm -1 and 850cm -1 The absorption peaks between 1500cm and 1500cm are mainly related to the stretching or vibration of the CO bond and the polar bond, indicating that the CO bond at this position has been cut. -1 The absorption peak at 20k is usually related to the vibration of aromatic CH bonds, indicating that the bond order and bond length on the benzene ring have changed. By observing the position and amplitude of the two typical characteristic peaks, it can be used as a characteristic basis for realizing the non-destructive testing method of epoxy resin molecules.
[0055] In summary, the embodiment of the present application provides a method for predicting the electrical properties of epoxy resin-based insulators, which can predict the electrical properties of epoxy insulators under different electric fields, including insulation resistance, dielectric loss, breakdown voltage, etc., and provide a theoretical basis and data support for the state evaluation and aging mechanism research of epoxy resin-based insulators. The steps are simple to operate, low in cost, and can be applied to the material state, performance evaluation and prediction of 500kVGIS insulators.
[0056] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.
Claims
1. A method for predicting the electrical properties of epoxy resin-based insulators, characterized in that: It includes the following steps: S1: Construct a single molecule model of epoxy resin-based insulating materials, use molecular simulation software to optimize the structure, and obtain a stable structure with the lowest molecular energy; S2: Apply an external electric field in the X-axis direction of the molecular chain to calculate the physical quantity data of the epoxy resin molecules in the initial state and the breakdown state; S3: Analyze the physical quantity data of epoxy resin molecules in the initial state and the breakdown state, calculate the changes in the dipole moment and polarizability of epoxy resin molecules under the action of an external electric field, and evaluate the stability of the epoxy resin molecular system; S4: Calculate the orbital energy level, energy gap and state density of epoxy resin molecules, and analyze the influence of external electric field on the electronic motion characteristics of epoxy resin molecules; S5: Analyze and process the calculation results of step S4 to obtain infrared spectrum data of epoxy resin molecules in different states, and establish a correlation between the electrical aging state of epoxy resin-based insulators and the infrared spectrum through the difference in infrared spectra, so as to realize the evaluation of the electrical aging state of epoxy resin-based insulators.
2. A method for predicting electrical properties of epoxy resin-based insulators according to claim 1, characterized in that: In the step S1, a single molecule model of epoxy resin-based insulating material is constructed, and its structural formula is as follows:
3. The method for predicting electrical properties of epoxy resin-based insulators according to claim 1, characterized in that: In the S1 step, the PM3 basis set based on the semi-empirical method is used to optimize the geometric configuration of the single-molecule model of the epoxy resin-based insulating material constructed to obtain a stable structure with the lowest molecular energy, so that the molecular geometry is neutral in the lowest energy state and has a single charge and spin state; the unrestricted Kohn-Sham method is used for calculation.
4. The method for predicting electrical properties of epoxy resin-based insulators according to claim 1, characterized in that: In the step S2, the applied external electric field is an electric dipole field; the initial state of the epoxy resin molecule is the state when the applied electric dipole field is 0, and the breakdown state of the epoxy resin molecule is the state when the molecular geometric structure shows obvious changes when the electric dipole field is applied using the trial method.
5. The method for predicting electrical properties of epoxy resin-based insulators according to claim 1, characterized in that: In the step S2, the physical quantity data of the epoxy resin molecule in the initial state include geometric configuration, dipole moment, polarizability, state density, energy gap distribution, molecular orbital and infrared spectrum; The physical quantity data of epoxy resin molecules in the breakdown state include geometric configuration, state density, energy gap distribution, molecular orbital and infrared spectrum.
6. The method for predicting electrical properties of epoxy resin-based insulators according to claim 1, characterized in that: In the step S4, the molecular orbital energy levels are calculated using Gaussian software, and the energy gap and state density are calculated using Multiwfn software.
7. The method for predicting electrical properties of epoxy resin-based insulators according to claim 1, characterized in that: In the step S5, the calculation results are analyzed and processed using Multiwfn software.
8. Application of the method according to any one of claims 1 to 7 in the material status, performance evaluation and prediction of 500kV GIS insulators.