Method and system for obtaining stress and characteristics of disc-type suspension porcelain insulator under large temperature difference

Abstract

The application discloses a method for obtaining stress and characteristics of disc-shaped suspension porcelain insulators under large temperature difference, and discloses a system and a medium with the method for obtaining stress and characteristics of disc-shaped suspension porcelain insulators under large temperature difference. The method deeply integrates numerical simulation and measured data, simultaneously considers the coupling effect of large temperature difference dynamic working conditions and typical defects in the porcelain, and constructs a closed-loop optimization process of "simulation modeling-measured checking-stress analysis-characteristics correlation-verification iteration", which not only solves the industry pain point that the full-size stress of complex structure insulators cannot be comprehensively and non-destructively measured, but also realizes the full-process landing from accurate stress acquisition to quantitative evaluation of operating characteristics, and provides a scientific basis for operation and maintenance, structure optimization and selection of insulators in large temperature difference areas.

Description

Technical Field

[0001] This invention relates to the field of power transmission and transformation technology, and in particular to a method and system for obtaining the stress and characteristics of disc suspension porcelain insulators under large temperature differences. Background Technology

[0002] Disc-type suspension porcelain insulators, with their excellent insulation performance, mechanical strength, and anti-aging properties, have been widely used in overhead transmission lines of various voltage levels in my country. In the high-latitude, high-altitude regions of northern my country, there exists a natural operating environment with extreme temperature differences. Winter temperatures can reach -60°C, and summer temperatures can reach 60°C, with diurnal temperature variations exceeding 20°C. Under these conditions, insulators simultaneously bear alternating thermal stress caused by large temperature differences, the weight of the conductors, and continuous mechanical loads from ice and snow accumulation. These are compounded by internal defects naturally present during the porcelain manufacturing process, such as pores, impurities, and microcracks. These defects easily lead to stress concentration at the defect sites, accelerating porcelain deterioration and even causing serious faults such as insulator breakage and breakdown, posing a significant threat to the reliability of the power grid.

[0003] Current research and applications of technologies related to stress distribution and operational characteristics of porcelain insulators still suffer from the following core defects and shortcomings: 1. The simulation conditions are seriously out of sync with the actual operating scenarios: Existing studies on stress distribution in porcelain insulators are mostly based on the standard temperature conditions (-40℃~40℃) of the national standard thermodynamic test. They do not match the extreme temperature difference range of -60℃~60℃ in the high latitude and high altitude areas of northern my country, nor do they consider the actual dynamic temperature change rate on site. As a result, the simulation calculation results deviate significantly from the actual operating conditions on site, and cannot meet the engineering application requirements of extreme environments.

[0004] 2. Insufficient credibility of simulation models and lack of full-process field verification: Existing finite element simulation analysis mostly involves separate modeling and calculation, with qualitative verification based on only a small amount of experimental data. There is a lack of comprehensive verification and correction of the material parameters and boundary conditions of the simulation model using field measurement data. The model settings deviate significantly from the actual working conditions with large temperature differences in the field, resulting in insufficient accuracy and engineering credibility of the stress field calculation results.

[0005] 3. The coupling effect of internal defects and large temperature difference is not considered, and the true stress state cannot be reflected: Existing stress analysis focuses on the ideal model of intact ceramic parts, and does not fully consider the coupling effect of large temperature difference cyclic load and typical internal defects (pores, impurities, microcracks) of ceramic parts. It cannot accurately capture the stress concentration effect at the defect, and it is difficult to restore the true stress state of the insulator during actual operation, and it is impossible to predict the deterioration risk in advance.

[0006] 4. Inability to achieve quantitative assessment of stress distribution and operational characteristics: Existing research only focuses on the acquisition and qualitative analysis of stress distribution, without establishing a quantitative correlation model between stress characteristic indicators and insulator operational characteristics. It is impossible to achieve quantitative assessment of insulator operational reliability, degradation rate, and failure risk through stress distribution data, making it difficult to directly guide the on-site operation and maintenance, structural optimization, and selection of insulators for transmission lines in areas with large temperature differences.

[0007] 5. Significant limitations of on-site testing methods: Existing on-site testing of insulators mostly involves offline destructive testing or local surface stress measurement. There is a lack of non-destructive testing methods for the full-size and full-thickness stress of insulators under large temperature difference environments. Moreover, the test results can only reflect the state of a single point and cannot achieve an overall assessment of the stress distribution and operating characteristics of the insulator. Summary of the Invention

[0008] This invention aims to address at least one of the technical problems existing in the prior art. To this end, this invention proposes a method for obtaining stress and characteristics of disc-type suspension porcelain insulators under large temperature differences. It deeply integrates numerical simulation with measured data, and considers the coupling effect of dynamic operating conditions with large temperature differences and typical defects inside the porcelain components. A closed-loop optimization process of "simulation modeling - measured verification - stress analysis - characteristic correlation - verification iteration" is constructed. This not only solves the industry pain point of the inability to comprehensively and non-destructively measure the full-size stress of complex insulator structures, but also realizes the implementation of the entire process from accurate stress acquisition to quantitative evaluation of operational characteristics, providing a scientific basis for the operation, maintenance, structural optimization, and selection of insulators in areas with large temperature differences.

[0009] This invention also proposes a system and medium for obtaining the stress and characteristics of disc suspension porcelain insulators under large temperature differences as described above.

[0010] A method for obtaining the stress and characteristics of a disc-type suspension porcelain insulator under large temperature difference according to a first aspect of the present invention is characterized by comprising the following steps: A three-dimensional full-size geometric model of a disc-shaped suspension porcelain insulator was constructed, and material parameters and boundary conditions were set to adapt to the thermal structure multiphysics coupling simulation of large temperature difference environment. The initial full-size stress distribution data of the insulator was obtained through transient coupling calculation. Based on the three-dimensional full-size geometric model, the key stress concentration areas of the insulator are selected as the measured points. The actual stress data of the measured points under large temperature difference environment is obtained. The actual stress data is quantitatively compared with the stress data of the corresponding position in the initial full-size stress distribution data. The material parameters and / or boundary conditions of the three-dimensional full-size geometric model are corrected according to the comparison results until the model error meets the preset threshold, and a high-confidence simulation model after verification is obtained. Based on the verified high-confidence simulation model, the corrected full-size stress distribution data of the insulator under large temperature difference environment is recalculated and exported, and core stress characteristic indicators including stress peak, stress concentration factor and defect stress amplification factor are extracted from the corrected full-size stress distribution data. A quantitative correlation model is established with the core stress characteristic index as input variable and the insulator operating characteristics as output variable. The core stress characteristic index is substituted into the quantitative correlation model to calculate the quantitative operating characteristic index of the insulator.

[0011] The method for obtaining the stress and characteristics of a disc-type suspension porcelain insulator under large temperature differences according to an embodiment of the present invention has at least the following beneficial effects: Strong adaptability to operating conditions and close to actual on-site operating scenarios: The simulation model constructed by this invention can adapt to the extreme large temperature difference range of -60℃ to 60℃, and the dynamic temperature change rate can be customized. It is fully adapted to the extreme operating environment of high latitude and high altitude regions in northern my country, which solves the problem of the existing technology's simulation conditions being out of touch with the actual scenario, and greatly improves the engineering applicability of the simulation results.

[0012] High simulation accuracy and reliability: This invention establishes a closed-loop verification mechanism of "local measured verification of global simulation". It uses non-destructive measured data of key areas to quantitatively correct the simulation model, and controls the root mean square error between the simulation results and the measured data to within 10%. This ensures the accuracy and engineering reliability of the full-size stress calculation results and solves the problem of insufficient accuracy and lack of comprehensive verification of existing individual simulation models.

[0013] High stress calculation accuracy, capable of precisely capturing stress concentration effects at defects: This invention achieves accurate stress calculation under the coupling effect of defects and large temperature differences through refined modeling with typical internal defects and the sub-model method. The calculation results of the sub-model method and the overall model do not differ by more than 3.5%, meeting the engineering accuracy requirements. It can accurately restore the real stress state of insulators in actual operation, capture the stress concentration effect at defects, and provide accurate data support for the prediction of deterioration risks.

[0014] This invention achieves a quantitative assessment of the entire process from stress distribution to operational characteristics: It establishes a quantitative correlation model between stress characteristic indicators and insulator operational characteristics. It can directly calculate the insulator's operational reliability, estimated degradation years, and ultimate tolerance temperature difference / load value through stress distribution data. This breaks through the limitation of existing technologies that can only qualitatively analyze stress distribution and can directly guide the on-site operation and maintenance, structural optimization, and selection of insulators for transmission lines in areas with large temperature differences.

[0015] This invention overcomes the technical limitations of on-site testing: It integrates the technical advantages of numerical simulation and non-destructive testing. It ensures the accuracy of the model through non-destructive testing and realizes the overall acquisition of stress across the entire size and thickness of the insulator through simulation. This solves the industry pain point that existing on-site testing methods can only perform offline destructive tests or local single-point measurements and cannot achieve overall assessment of stress across the entire size, thus greatly improving the comprehensiveness and convenience of insulator condition testing.

[0016] High versatility and iterability: This invention constructs a closed-loop process of "simulation modeling - actual measurement verification - stress analysis - characteristic correlation - verification iteration", which can be adapted to different models and grades of disc suspension porcelain insulators. Through iterative optimization, the matching degree between the model output and the actual working conditions can reach more than 90%, which has extremely strong engineering promotion value.

[0017] According to some embodiments of the present invention, after the step of establishing a quantitative correlation model with the core stress characteristic index as input variable and the insulator operating characteristics as output variable, and substituting the core stress characteristic index into the quantitative correlation model to calculate the quantitative operating characteristic index of the insulator, the method further includes: The quantitative operational characteristic indicators are verified using actual state data of insulators in operation on-site, and the three-dimensional full-size geometric model and / or the quantitative correlation model are iteratively optimized based on the verification deviation.

[0018] According to some embodiments of the present invention, the three-dimensional full-size geometric model includes ceramic parts, steel feet, iron caps, and cement adhesive components; and typical internal defect models, including pores, impurities, or microcracks, are added to areas of high stress concentration in the ceramic parts.

[0019] According to some embodiments of the present invention, the internal defect model uses a sub-model method for stress calculation: first, a complete ceramic part model without defects is simulated as a whole, and a local area containing defects is selected as a sub-model. The triaxial principal stresses obtained from the overall simulation are used as the boundary stresses of the sub-model. Then, mesh refinement and defect modeling calculations are performed on the sub-model.

[0020] According to some embodiments of the present invention, the boundary conditions include: Thermal boundary conditions, based on actual monitoring data of large temperature difference environments, define a dynamic temperature function to simulate the extreme temperature range and rate of temperature change from -60℃ to 60℃; and, The mechanical boundary condition simulates the actual stress state of the insulator when it is connected to the grid. It applies 60% to 100% of the rated load to the lower end of the steel foot and sets the contact point between the iron cap and the steel foot as a fixed constraint.

[0021] According to some embodiments of the present invention, the key stress concentration areas include the outer neck corner and the inner opening of the head of the ceramic part; the means of obtaining actual stress data include on-site non-destructive measurement using fiber Bragg gratings or resistance strain gauges, and converting the measured strain data into stress data through the stress-strain relationship of the material.

[0022] According to some embodiments of the present invention, the index for quantitatively comparing the actual stress data with the simulated stress data is the root mean square error; the preset threshold is that the root mean square error is less than or equal to 10%.

[0023] According to some embodiments of the present invention, the core stress characteristic index further includes: The maximum first principal stress value and its location, the stress concentration factor of the stress concentration zone, the stress amplification factor at the defect, and the dynamic response curve of stress with temperature change; among them, the first principal stress is the core analytical index of brittle ceramic materials.

[0024] According to some embodiments of the present invention, the quantitative correlation model is trained using multivariate nonlinear regression or machine learning algorithms, with peak stress, stress concentration factor, and defect stress amplification factor as input variables and operational reliability, degradation rate, and failure risk as output variables.

[0025] According to some embodiments of the present invention, the quantitative operating characteristic indicators include: operating reliability, estimated degradation years, ultimate tolerance temperature difference value, and ultimate tolerance mechanical load value.

[0026] A system for acquiring stress distribution and operating characteristics of a disc suspension porcelain insulator under large temperature difference conditions according to a second aspect embodiment of the present invention, characterized in that it comprises: The simulation modeling module can construct a three-dimensional full-size geometric model of a disc-shaped suspension porcelain insulator, and set material parameters and boundary conditions for multi-physics coupling simulation of thermal structure to adapt to large temperature difference environments. Through transient coupling calculation, the initial full-size stress distribution data of the insulator can be obtained. The actual measurement and verification module can select the key stress concentration areas of the insulator as actual measurement points based on the three-dimensional full-size geometric model, obtain the actual stress data of the actual measurement points under large temperature difference environment, quantitatively compare the actual stress data with the stress data at the corresponding positions in the initial full-size stress distribution data, and correct the material parameters and / or boundary conditions of the three-dimensional full-size geometric model according to the comparison results until the model error meets the preset threshold, and obtain a verified high-confidence simulation model. The stress feature extraction module can recalculate and export the corrected full-size stress distribution data of the insulator under large temperature difference environment based on the verified high-confidence simulation model, and extract core stress feature indicators including stress peak, stress concentration factor and defect stress amplification factor from the corrected full-size stress distribution data. The operating characteristic acquisition module can establish a quantitative correlation model with the core stress characteristic index as input variable and the insulator operating characteristics as output variable. By substituting the core stress characteristic index into the quantitative correlation model, the quantitative operating characteristic index of the insulator can be calculated.

[0027] According to a third aspect of the present invention, a computer-readable storage medium stores computer-executable instructions for performing the above-described method for obtaining the stress and characteristics of a disc suspension porcelain insulator under large temperature differences.

[0028] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram illustrating the steps of the method for obtaining the stress and characteristics of a disc-shaped suspension porcelain insulator under large temperature differences according to an embodiment of the present invention. Figure 2 This is a geometric model diagram of a disc-shaped suspension porcelain insulator, illustrating the method for obtaining stress and characteristics of a disc-shaped suspension porcelain insulator under large temperature differences according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the key area measurement point layout for the method of obtaining stress and characteristics of disc suspension porcelain insulators under large temperature difference in an embodiment of the present invention. Figure 4 This is a cloud map showing the distribution of the first principal stress of the insulator ceramic component in the method for obtaining the stress and characteristics of a disc-shaped suspension porcelain insulator under large temperature difference according to an embodiment of the present invention. Figure 5 This is a framework diagram of the stress characteristics and operational characteristics correlation model of the method for obtaining stress and characteristics of disc suspension porcelain insulators under large temperature differences according to an embodiment of the present invention. Figure 6 The structural block diagram of the system for obtaining stress and characteristics of disc suspension porcelain insulators under large temperature differences provided in the embodiments of the present invention is shown. Detailed Implementation

[0030] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0031] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0032] Example 1 This embodiment uses a 550kN-class disc-type suspension porcelain insulator, widely used in transmission lines in high-altitude, large-temperature-difference regions of northern my country, as the test object to describe the specific implementation process of the invention in detail. Those skilled in the art can repeat the technical solution of the invention based on this embodiment. Figure 1 As shown, the invention includes at least the following steps: Step S1: Construct a three-dimensional full-size geometric model of the disc suspension porcelain insulator, and set material parameters and boundary conditions to adapt to the thermal-structural multiphysics coupling simulation of large temperature difference environment. Obtain the initial full-size stress distribution data of the insulator through transient coupling calculation.

[0033] S11 Three-dimensional geometric model creation and mesh generation.

[0034] Based on the actual dimensions of the 550kN-rated disc suspension porcelain insulator, a full-size assembly geometric model was created in CAD 3D modeling software, such as... Figure 2 As shown, the model consists of four core components: ceramic parts, iron caps, steel feet, and cement adhesive. Minor structures such as ceramic glaze and ceramic sand, which do not affect stress distribution, are ignored, thus simplifying the model while ensuring simulation accuracy.

[0035] To simulate the impact of actual internal defects in ceramic parts, typical porosity defect models were added to two major stress concentration areas: the outer neck corner and the inner rounded corner of the head. The pores were designed as spheres made of air with a radius of 0.05 mm, closely matching the typical defect size range in actual ceramic part production.

[0036] The geometric model was imported into mesh generation software, and unstructured meshing was used to refine the mesh locally at the contact interfaces between the ceramic part and the cement adhesive, the steel feet, stress concentration areas, and areas with porosity defects. Five layers of mesh were used in the thickness direction to ensure accurate capture of temperature and stress gradients. To address the issue that the size of the porosity defects was much smaller than the overall size, a sub-model method was used for precise calculation of the defect area: first, a complete simulation of the intact ceramic part was performed, and a 1mm × 1mm × 1mm local area containing the defect was extracted as a sub-model. The triaxial principal stresses obtained from the overall simulation were used as the boundary stresses of the sub-model. The sub-model was then meshed separately, with the mesh size for the defect area set to 0.01mm, completing the defect modeling and calculation.

[0037] Step S12: Setting up and calculating multi-physics coupled finite element simulation under large temperature difference conditions.

[0038] Material parameter definition: Temperature-dependent material properties of each component are defined in the finite element simulation software COMSOL. The core parameter settings are as follows: Ceramic material thermal expansion coefficient 6.7 × 10⁻⁶. -6 / K, elastic modulus 100GPa, Poisson's ratio 0.22; cementitious adhesive thermal expansion coefficient 9.5×10 -6 / K, elastic modulus 27GPa, Poisson's ratio 0.2; the iron cap and steel feet are made of Q235 steel with a coefficient of thermal expansion of 11.5×10. -6 / K, elastic modulus 206GPa, Poisson's ratio 0.3.

[0039] Boundary condition settings: Thermal boundary conditions: Based on actual temperature monitoring data from high-altitude areas in northern my country, a dynamic temperature function is set to simulate an extreme temperature range of -60℃ to 60℃, with a temperature change rate of 20℃ / h. A solid-state heat transfer physical field is established, defining the contact heat transfer coefficient between components as 1000 W / (m²). 2 ·K).

[0040] Mechanical boundary conditions: To simulate the actual stress state of the insulator when it is connected to the grid, 60% (330kN) of the rated load of 550kN is applied to the lower end of the steel foot, and an additional 20% of the icing load is added, for a total applied load of 440kN; the upper end of the iron cap is set as a fixed constraint to simulate the fixing effect of the tower.

[0041] Multiphysics coupling simulation calculation: Select the transient coupling physical field of solid heat transfer-solid mechanics. Based on the equilibrium equation of elasticity, geometric equation and generalized Hooke's law, set the simulation time step to 0.5h to match the temperature change period, solve the transient temperature field and stress field distribution of the insulator under large temperature difference, and output the first principal stress as the core analysis index to obtain the initial full-size stress distribution data of the insulator.

[0042] Step S2: Based on the three-dimensional full-size geometric model, select the key stress concentration area of ​​the insulator as the measured point, obtain the actual stress data of the measured point under a large temperature difference environment, quantitatively compare the actual stress data with the stress data at the corresponding position in the initial full-size stress distribution data, and correct the material parameters and / or boundary conditions of the three-dimensional full-size geometric model according to the comparison results until the model error meets the preset threshold, and obtain a verified high-confidence simulation model.

[0043] Step S21: Acquire measured stress data in key areas.

[0044] Selection of measurement points: Key stress concentration areas such as the outer neck corner and the inner opening of the head of the ceramic part were selected as measurement points. Three repeated measurement points were set in each area to ensure data reliability. The specific layout of the measurement points and the sensor installation method are as follows: Figure 3 As shown, three repeat measurement points are set for each area.

[0045] Actual measurement operation: High-temperature resistance strain gauges, equipped with temperature compensation plates, were attached to the measurement points of the same type of 550kN insulator operating in a large temperature difference region. Static strain gauges were used to collect strain data of the insulator in real time as the temperature rose from -60℃ to 60℃, with a sampling frequency of once per 0.5 hours, synchronized with the simulation time step. The collected strain data were converted into stress data based on the stress-strain relationship of the ceramic material.

[0046] Data preprocessing: The measured stress data is subjected to moving average filtering and noise reduction to eliminate interference from environmental vibration and temperature changes, and temperature-stress corresponding data synchronized with the simulation conditions are extracted.

[0047] Step S22: Simulation model verification and correction.

[0048] The average stress data at the three measured points were quantitatively compared with the stress data at the corresponding locations under the same working conditions in the simulation model, and the root mean square error was calculated.

[0049] In this embodiment, the root mean square error (RMSE) between the initial simulation results and the measured data was 12.3%, exceeding the 10% threshold. Therefore, the model was corrected: the temperature-dependent elastic modulus and thermal expansion coefficient of the cementitious adhesive were optimized based on the measured data, and the contact heat transfer coefficient was also corrected. After correction, the simulation calculation was repeated, and the final RMSE between the simulation results and the measured data was 7.8%, less than or equal to 10%. The simulation model was deemed valid, and a verified high-confidence simulation model was obtained.

[0050] Step S3: Based on the verified high-confidence simulation model, recalculate and export the corrected full-size stress distribution data of the insulator under large temperature difference environment, and extract the core stress characteristic indicators including stress peak, stress concentration factor and defect stress amplification factor from the corrected full-size stress distribution data.

[0051] Step S31: Obtain full-size stress distribution.

[0052] Based on the validated simulation model, stress distribution cloud maps and data files for the full dimensions and entire area of ​​a 550kN disc-type suspension porcelain insulator under large temperature difference conditions were exported. Analysis revealed that the inner arc corner of the porcelain insulator head is the location of maximum stress, with a maximum first principal stress of 127MPa. Stress is significantly concentrated at the porosity defects, with a stress amplification factor of 2.8. The calculated first principal stress distribution cloud map of the insulator porcelain component under large temperature difference conditions is shown below. Figure 4 As shown, the color gradation visually illustrates the stress distribution pattern across the entire region.

[0053] Step S32: Extraction of core stress features.

[0054] The core stress characteristic indicators are extracted as follows: maximum first principal stress value of 127 MPa, stress concentration factor of 2.2 in the stress concentration area, stress amplification factor of 2.8 at the defect, and dynamic response curve of stress with temperature change.

[0055] Step S4: Establish a quantitative correlation model with the core stress characteristic index as input variable and the insulator operating characteristics as output variable. Substitute the core stress characteristic index into the quantitative correlation model to calculate the quantitative operating characteristic index of the insulator.

[0056] Step S41: Basic data collection.

[0057] We collected data on the intrinsic bending strength of the porcelain insulator of this model (170 MPa), fatigue test data on defect propagation under different stress conditions, and field operation failure data and deterioration detection data of this model of insulator in the high-altitude and large temperature difference region of Northwest my country over the past 10 years.

[0058] Step S42: Establishment of quantitative correlation model and acquisition of operational characteristics.

[0059] Using peak stress, stress concentration factor, and defect stress amplification factor as input variables, and operational reliability, degradation rate, and failure risk as output variables, a quantitative correlation model was trained using a random forest machine learning algorithm. The constructed framework of the stress characteristic-operational characteristic correlation model is as follows: Figure 5 As shown, the correspondence between input variables, model algorithm, and output variables is clearly defined. The goodness-of-fit R-value of the model is verified through field operation data. 2The value is 0.942, which is within the acceptable range for prediction error.

[0060] Substituting the extracted stress characteristic indices into the correlation model, the quantitative operating characteristic indices of the insulator under the target large temperature difference environment were calculated: annual operating reliability 0.9987, estimated deterioration period 28 years, ultimate temperature difference tolerance 130℃, and ultimate mechanical load tolerance 620kN.

[0061] Furthermore, embodiments of the present invention also include: Step S5: Utilize the actual state data of the insulators in operation on-site to verify the quantitative operational characteristic indicators, and iteratively optimize the three-dimensional full-size geometric model and / or the quantitative correlation model based on the verification deviation.

[0062] Step S51 On-site verification.

[0063] Ten sets of insulators of the same type that have been in operation for 15 years in this large temperature difference region were selected. Their operating characteristic indicators were obtained by this method and compared with the actual test data of the insulators in the field power frequency withstand voltage test and residual mechanical strength test. The matching degree between the model prediction results and the actual operating state was 92.7%, which meets the requirement of more than 90%.

[0064] Step S52: Iterative optimization.

[0065] To address the prediction bias of a small number of samples, the weight coefficients of the correlation model are optimized, ultimately forming a final technical method adapted to this region and this type of insulator.

[0066] As can be seen from the above embodiments, the present invention deeply integrates numerical simulation with measured data, and simultaneously considers the coupling effect of dynamic working conditions with large temperature differences and typical defects inside the ceramic components. It constructs a closed-loop optimization process of "simulation modeling - measured verification - stress analysis - characteristic correlation - verification iteration", which can realize the accurate acquisition of stress distribution and quantitative evaluation of operating characteristics of disc suspension ceramic insulators under large temperature difference conditions, and has significant engineering application value.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0068] Example 2 Another embodiment of the present invention provides a system for obtaining the stress and characteristics of a disc-type suspension porcelain insulator under large temperature differences, such as... Figure 6 As shown, the system includes: The simulation modeling module 601 can construct a three-dimensional full-size geometric model of a disc-shaped suspension porcelain insulator, and set material parameters and boundary conditions for multi-physics coupling simulation of thermal structure to adapt to large temperature difference environments. Through transient coupling calculation, the initial full-size stress distribution data of the insulator can be obtained. The actual measurement and verification module 602 can select the key stress concentration area of ​​the insulator as the actual measurement point based on the three-dimensional full-size geometric model, obtain the actual stress data of the actual measurement point under a large temperature difference environment, quantitatively compare the actual stress data with the stress data calculated by the simulation model at the corresponding position, and correct the material parameters and / or boundary conditions of the simulation model according to the comparison results until the model error meets the preset threshold, and obtain a verified high-confidence simulation model. The stress feature extraction module 603 is able to recalculate and export the full-size stress distribution data of the insulator under a large temperature difference environment based on the verified high-confidence simulation model, and extract core stress feature indicators including stress peak, stress concentration factor and defect stress amplification factor from the full-size stress distribution data. The operating characteristic acquisition module 604 can establish a quantitative correlation model with the core stress characteristic index as the input variable and the insulator operating characteristics as the output variable. The core stress characteristic index is substituted into the quantitative correlation model to calculate the quantitative operating characteristic index of the insulator. The verification iteration module 605 can use the actual state data of the insulators in operation on the field to verify the quantitative operation characteristic indicators, and perform iterative optimization of the three-dimensional full-size geometric model and / or the quantitative correlation model based on the verification deviation.

[0069] The specific workflows of the above modules correspond to steps one through five in Embodiment 1, and will not be repeated here. Those skilled in the art should understand that the above modules can be integrated into a single processor or distributed across different computing devices. The names of the modules are used only for functional differentiation and do not constitute a limitation on the scope of protection of this invention.

[0070] Example 3 Another embodiment of the present invention provides a computer-readable storage medium having computer-executable instructions stored thereon. When the computer-executable instructions are executed by one or more processors, they can realize the method for obtaining the stress and characteristics of a disc suspension porcelain insulator under large temperature differences as described in Embodiment 1.

[0071] The computer-readable storage medium may include, but is not limited to: read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), flash memory, optical disc (CD-ROM, DVD), magnetic cartridges, magnetic tape, disk storage devices, or other magnetic storage devices. The instructions may be written in programming languages ​​including C++, Python, and MATLAB, and may be invoked and executed on finite element simulation software platforms such as COMSOL and ANSYS.

[0072] When the instruction is executed by the processor, the following operations are performed: constructing a three-dimensional full-size geometric model of the insulator and setting boundary conditions for large temperature difference multi-physics field coupling simulation; verifying and correcting the simulation model based on measured data; extracting core stress characteristic indicators from the full-size stress distribution; establishing a quantitative correlation model between stress characteristics and operating characteristics and calculating operating characteristic indicators; verifying and iteratively optimizing the model using field data. For specific implementation details, please refer to Example 1, which will not be repeated here.

[0073] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments.

[0074] The above is a detailed description of the preferred embodiments of this application. However, this application is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A method for obtaining the stress and characteristics of a disc-shaped suspension porcelain insulator under large temperature differences, characterized in that, Includes the following steps: A three-dimensional full-size geometric model of a disc-shaped suspension porcelain insulator was constructed, and material parameters and boundary conditions were set to adapt to the thermal structure multiphysics coupling simulation of large temperature difference environment. The initial full-size stress distribution data of the insulator was obtained through transient coupling calculation. Based on the three-dimensional full-size geometric model, the key stress concentration areas of the insulator are selected as measured points. The actual stress data of the measured points under large temperature difference conditions are obtained. The actual stress data is quantitatively compared with the stress data at the corresponding positions in the initial full-size stress distribution data. The material parameters and / or boundary conditions of the three-dimensional full-size geometric model are corrected according to the comparison results until the model error meets the preset threshold, and a high-confidence simulation model with verification is obtained. Based on the verified high-confidence simulation model, the corrected full-size stress distribution data of the insulator under large temperature difference environment is recalculated and exported, and core stress characteristic indicators including stress peak, stress concentration factor and defect stress amplification factor are extracted from the corrected full-size stress distribution data. A quantitative correlation model is established with the core stress characteristic index as input variable and the insulator operating characteristics as output variable. The core stress characteristic index is substituted into the quantitative correlation model to calculate the quantitative operating characteristic index of the insulator.

2. The method according to claim 1, characterized in that, After the step of establishing a quantitative correlation model with the core stress characteristic index as input variable and the insulator operating characteristics as output variable, and substituting the core stress characteristic index into the quantitative correlation model to calculate the quantitative operating characteristic index of the insulator, the method further includes: The quantitative operational characteristic indicators are verified using actual state data of insulators in operation on-site, and the three-dimensional full-size geometric model and / or the quantitative correlation model are iteratively optimized based on the verification deviation.

3. The method according to claim 1, characterized in that, The three-dimensional full-size geometric model includes ceramic parts, steel feet, iron caps, and cement adhesive components; and typical internal defect models, including pores, impurities, or microcracks, are added to areas of high stress concentration in the ceramic parts.

4. The method according to claim 3, characterized in that, The internal defect model uses a sub-model method for stress calculation: first, the intact ceramic part model without defects is simulated as a whole, and the local area containing defects is selected as a sub-model. The triaxial principal stress obtained from the overall simulation is used as the boundary stress of the sub-model. Then, the sub-model is meshed and the defect model is calculated.

5. The method according to claim 1, characterized in that, The boundary conditions include: Thermal boundary conditions, based on actual monitoring data of large temperature difference environments, define a dynamic temperature function to simulate the extreme temperature range and rate of temperature change from -60℃ to 60℃; and, The mechanical boundary condition simulates the actual stress state of the insulator when it is connected to the grid. It applies 60% to 100% of the rated load to the lower end of the steel foot and sets the contact point between the iron cap and the steel foot as a fixed constraint.

6. The method according to claim 1, characterized in that, The key stress concentration areas include the outer neck corner and the inner opening of the head of the ceramic part; the means of obtaining actual stress data include on-site non-destructive measurement using fiber Bragg gratings or resistance strain gauges, and converting the measured strain data into stress data through the stress-strain relationship of the material.

7. The method according to claim 1, characterized in that, The indicator used to quantitatively compare the actual stress data with the simulated stress data is the root mean square error (RMSE); the preset threshold is an RMSE less than or equal to 10%.

8. The method according to claim 1, characterized in that, The core stress characteristic indicators also include: The maximum first principal stress value and its location, the stress concentration factor of the stress concentration zone, the stress amplification factor at the defect, and the dynamic response curve of stress with temperature change; among them, the first principal stress is the core analytical index of brittle ceramic materials.

9. The method according to claim 1, characterized in that, The quantitative correlation model is trained using multivariate nonlinear regression or machine learning algorithms, with peak stress, stress concentration factor, and defect stress amplification factor as input variables and operational reliability, degradation rate, and failure risk as output variables.

10. The method according to claim 1, characterized in that, The quantitative operational characteristic indicators include: operational reliability, estimated degradation years, extreme temperature difference tolerance, and extreme mechanical load tolerance.

11. A system for obtaining stress and characteristics of a disc-type suspension porcelain insulator under large temperature differences, characterized in that, include: The simulation modeling module can construct a three-dimensional full-size geometric model of a disc-shaped suspension porcelain insulator, and set material parameters and boundary conditions for multi-physics coupling simulation of thermal structure to adapt to large temperature difference environments. Through transient coupling calculation, the initial full-size stress distribution data of the insulator can be obtained. The actual measurement and verification module can select the key stress concentration areas of the insulator as actual measurement points based on the three-dimensional full-size geometric model, obtain the actual stress data of the actual measurement points under large temperature difference environment, quantitatively compare the actual stress data with the stress data at the corresponding positions in the initial full-size stress distribution data, and correct the material parameters and / or boundary conditions of the three-dimensional full-size geometric model according to the comparison results until the model error meets the preset threshold, and obtain a verified high-confidence simulation model. The stress feature extraction module can recalculate and export the corrected full-size stress distribution data of the insulator under large temperature difference environment based on the verified high-confidence simulation model, and extract core stress feature indicators including stress peak, stress concentration factor and defect stress amplification factor from the corrected full-size stress distribution data. The operating characteristic acquisition module can establish a quantitative correlation model with the core stress characteristic index as input variable and the insulator operating characteristics as output variable. By substituting the core stress characteristic index into the quantitative correlation model, the quantitative operating characteristic index of the insulator can be calculated.

12. A computer-readable storage medium storing computer-executable instructions for performing the method of any one of claims 1 to 10.

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