ANSYS ICEPAK-based method for simulating temperature fields of inner layer and outer layer of overhead transmission conductor

Abstract

The invention discloses an ANSYS ICEPAK-based overhead transmission conductor inner and outer layer temperature field simulation method, which comprises the following steps of: establishing a three-dimensional solid model of a conductor through ANSYS ICEPAK software, delimiting a calculation area, defining strand material attributes, and setting an accurate boundary condition and a grid division scheme; on the basis of considering the current-carrying capacity of the wire, the environmental parameters and the winding angle of the strand wire, the temperature field distribution inside and outside the wire is solved by adopting a multi-physics field coupling simulation technology; obtaining a convergence result through iterative solution, and outputting detailed data including a temperature distribution cloud picture, a minimum value, a maximum value, an average value and the like of each layer of strand temperature; according to the method, the professional function of ANSYS ICEPAK is utilized, additional measuring equipment is not needed, temperature distribution of the wire under different operation conditions is efficiently and visually presented, powerful technical support is provided for operation safety, design optimization and maintenance decision of a power transmission line, and meanwhile calculation precision and engineering practicability are greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of power transmission line operation and maintenance engineering, and in particular to a method for simulating temperature fields of inner and outer layers of overhead power transmission lines based on ANSYS ICEPAK. Background Art

[0002] With the continuous development of power systems, temperature monitoring and precise calculation of overhead transmission lines have become key links to ensure safe operation of transmission lines, extend equipment life, and optimize transmission efficiency. The temperature field distribution of conductors under different working conditions, especially the temperature changes under the influence of complex environmental factors, has a direct impact on the stable operation of the transmission system. The increase in conductor temperature is not only related to the safety of transmission lines, but may also lead to accelerated aging of lines, frequent failures, and even safety accidents. Therefore, accurate simulation and analysis of the temperature field of overhead transmission lines has important practical significance and urgent needs.

[0003] In order to accurately predict the change of conductor temperature, a variety of methods and devices have been proposed and applied in practice. However, these methods still have certain technical limitations and shortcomings. For example, CN118940535A discloses a temperature monitoring device, which, as a traditional sensor-based monitoring device, can monitor the temperature state of the conductor in real time. However, this method is highly dependent on the density and location of the sensor, which makes it difficult to perform effective temperature monitoring in long-distance transmission lines or inaccessible areas; in addition, the sensor monitoring method cannot provide a global analysis of the conductor temperature distribution, which limits its application effect under complex working conditions.

[0004] Another method is a temperature estimation method based on a steady-state heat conduction model. For example, the method disclosed in CN118940535A can estimate the temperature of the conductor under steady-state conditions, but ignores the time-varying characteristics of the temperature field. When the current load fluctuates or external environmental factors (such as wind speed, solar radiation, etc.) change, the application of the steady-state model may produce large errors and cannot accurately predict the temperature changes of the conductor under complex and dynamic conditions.

[0005] In addition, some temperature simulation methods based on finite element analysis have been proposed, such as the temperature simulation method based on ANSYS APDL and ANSYS CFX disclosed in CN106055387B and the radial temperature field simulation method of overhead lines based on ANSYS CFX disclosed in CN106202610B; although these methods can simulate the radial temperature field of the conductor to a certain extent through finite element analysis, they are mainly limited to the simulation of two-dimensional temperature fields; in complex three-dimensional structures or large-span transmission lines, these methods are difficult to fully consider the three-dimensional temperature distribution of the conductor, especially the influence of external environmental factors such as wind speed and solar radiation on the conductor temperature field. Therefore, the application effect of these methods in three-dimensional temperature field simulation is limited.

[0006] In summary, the existing technology still has significant limitations in the simulation analysis of the temperature field of overhead transmission lines, especially in the simulation accuracy, scope of application and comprehensive consideration of external environmental factors of the three-dimensional temperature field. In order to solve the above problems, the present invention proposes a simulation method for the inner and outer temperature fields of overhead transmission lines based on ANSYS ICEPAK. The method aims to provide accurate three-dimensional temperature field simulation analysis by comprehensively considering the geometric structure, operating conditions and external environmental factors of the conductor, so as to more accurately describe the temperature distribution of the conductor under different working conditions, and provide strong technical support for the safe operation, design optimization and maintenance of the conductor. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a method for simulating the temperature field of the inner and outer layers of overhead power transmission lines based on ANSYS ICEPAK, so as to solve the shortcomings of the temperature field simulation of overhead power transmission lines in terms of accuracy, scope of application and consideration of external environmental factors, especially in the field of three-dimensional temperature field simulation: Specifically, in the prior art, although there are temperature monitoring devices based on sensors and temperature estimation methods based on steady-state heat conduction models, these methods have limitations, such as restrictions on sensor layout, inability to provide global analysis of temperature distribution, and the possibility of large errors in the application of steady-state models under dynamic conditions. In addition, although there are temperature simulation methods based on ANSYS APDL and ANSYS CFX and radial temperature field simulation methods for overhead lines based on ANSYS CFX, these methods are only applicable to two-dimensional temperature fields and cannot fully consider the three-dimensional temperature distribution of the conductor.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for simulating the temperature field of the inner and outer layers of overhead transmission lines based on ANSYS ICEPAK, which comprehensively considers the influence of the current carrying capacity, heat conduction, heat convection, heat radiation, wind speed and solar radiation of the conductor strands during operation through ANSYS ICEPAK software, and is implemented in the following steps: Step 1: According to the structural parameters of the conductor, a three-dimensional solid model is established using modeling software, and the calculation area is defined in ANSYSICEPAK; Step 2: Define the solid material properties of each strand, set accurate boundary conditions, and perform high-quality meshing on the model; Step 3: Based on the operating conditions, calculate the heating rate of each part of the conductor and input the environmental parameters; Step 4: Set the iteration accuracy, solve the three-dimensional thermal-fluid coupling field, and obtain the temperature distribution of the wire under various working conditions; Step 5: When the calculation results converge within the set accuracy range, post-processing analysis is performed; Step 6: Output detailed data of the temperature field, including the temperature distribution cloud map, the minimum, maximum and average temperature of each layer of strands.

[0009] In a preferred solution, the Step 1 uses modeling software to establish a three-dimensional solid model, and the modeling software includes but is not limited to SpaceClaim, DesignModeler, CAD and SolidWorks. At the same time, the three-dimensional model needs to be converted into a model approved by ICEPAK. The specific implementation steps of the Step 1 include: Step 1.1: Set the number of strands in the next outer layer to n, take the axial direction of the strands in the center layer as the reference direction, and construct the corresponding surface through the diagonal of the rectangle formed by the side length of the regular n-gon inscribed in the circular cross-section at both ends of the strands, and use the surface as the winding angle amplitude of the next outer layer of strands; Step 1.2: Then, array and stretch the single strand model in the modeling software to obtain a wire model with a real winding angle.

[0010] In the preferred solution, the model in Step 1 is set so that the electrical conductivity and thermal conductivity of each strand material are uniform, linear and isotropic, the heat exchange between the outer strands and the surrounding air is thermal convection, the wire is in an infinite space, and the influence of the electromagnetic field effect is ignored.

[0011] In a preferred solution, in the process of defining the calculation area in ANSYS ICEPAK in Step 1, two planes along the axial direction of the conductor are set to be closed, and four planes along the radial direction of the conductor are set to be open, so as to apply wind speed to the conductor.

[0012] In the preferred solution, the Step 2 meshing adopts the Mesher HD tool to generate a hybrid mesh, including hexahedral mesh, prismatic mesh and tetrahedral mesh. Local mesh refinement is adopted in key areas, and quality inspection is performed by the Skewness method to ensure that the mesh meets the requirements of subsequent simulation analysis.

[0013] In the preferred solution, when defining the solid material properties of each strand in Step 2, the material properties include density and specific heat capacity. If marked in the parameter table of the conductor nameplate, the nameplate shall prevail; if not marked, set it.

[0014] In a preferred solution, the environmental parameters in Step 3 include wind speed, wind direction, solar radiation intensity, solar heat absorption coefficient, radiation heat dissipation coefficient and ambient temperature.

[0015] In the preferred solution, the heating rate of each part of the wire is calculated in Step 3, and the Joule heat continuously generated by the wire is calculated to simulate the heat source of the wire. It is directly input in the interface of defining the wire properties. Taking steel wire and aluminum wire as examples, the ratio of the current passing through the steel wire and the aluminum wire is: (1); The heat generation rate per unit volume of steel strands is: (2); The heat generation rate per unit volume of aluminum strands is: (3); In the formula, , Represent the current passing through the steel strand and the aluminum strand respectively; , represent the resistance of steel strands and aluminum strands respectively; , represent the resistivity of steel strands and aluminum strands, respectively; , Respectively represent the radial cross-sectional areas of the steel strand and the aluminum strand; , Represent the volumes of steel strands and aluminum strands respectively.

[0016] In a preferred solution, the iteration accuracy in Step 4 is set according to engineering requirements.

[0017] In the preferred solution, in Step 6, the heat-flux coupled temperature field solved by ANSYS ICEPAK can output detailed data of the temperature field, including a temperature distribution cloud map, and the minimum, maximum and average temperature of each layer of strands.

[0018] The method for simulating the temperature field of the inner and outer layers of overhead power transmission lines based on ANSYS ICEPAK provided by the present invention has the following beneficial effects: 1. The present invention solves the shortcomings of temperature field simulation of overhead power transmission lines in terms of accuracy, scope of application and consideration of external environmental factors, especially in the field of three-dimensional temperature field simulation. Traditional methods often rely on sensors, have layout limitations, and are difficult to provide global temperature distribution analysis; at the same time, two-dimensional simulation methods cannot fully consider the three-dimensional temperature distribution of the conductor and the influence of external environmental factors; 2. The present invention overcomes the limitations of traditional two-dimensional simulation methods by using three-dimensional models and multi-physical field coupling simulation technology. Traditional two-dimensional methods cannot fully describe the temperature distribution under complex three-dimensional structures, especially when considering external environmental factors such as wind speed and solar radiation. There are large errors. The present invention adopts a three-dimensional model, which can more comprehensively reflect the temperature changes of the conductor under complex working conditions. 3. The method of the present invention adopts a three-dimensional model and takes into account the influence of external environmental factors such as wind speed and solar radiation. At the same time, it adopts multi-physics field coupling simulation technology and comprehensively considers the current carrying capacity, heat conduction, heat convection, heat radiation and other aspects of the conductor, thereby improving the accuracy of the calculation results. This makes the simulation results closer to the actual situation and provides strong technical support for the operation safety, design optimization and maintenance decision-making of the transmission line; 4. The present invention uses the Mesher HD tool to perform high-quality meshing and locally refines the mesh in key areas (such as heat sources, boundary layers, etc.), ensuring that the mesh quality meets the requirements of subsequent simulation analysis, which helps to improve the accuracy of simulation results and makes the calculation of temperature fields more accurate; 5. The present invention fully considers the influence of external environmental factors such as wind speed and solar radiation on the temperature distribution of the conductor during the calculation process. These external environmental factors often have a significant impact on the temperature distribution of the conductor in actual operation, while traditional methods often ignore these factors. The simulation method of the present invention is closer to the actual situation and provides a strong guarantee for the safe operation of the power system; 6. The present invention significantly improves the calculation accuracy by means of three-dimensional model, multi-physics field coupling simulation technology and high-precision grid division, which can more accurately describe the temperature distribution of the conductor under different working conditions, and provide an important theoretical basis for the operation safety, design optimization and conductor maintenance of the power system; 7. The present invention does not require additional measuring equipment and can efficiently and intuitively present the temperature distribution of the conductor under different operating conditions, which avoids the limitations of sensor layout and makes the simulation process more efficient and convenient. At the same time, by outputting detailed data such as the temperature distribution cloud map, the minimum, maximum and average temperature of each layer of strands, the present invention provides engineers with intuitive and comprehensive temperature field information, which helps to make more accurate decisions; 8. The present invention significantly improves the accuracy and applicability of the temperature field simulation of overhead transmission lines by adopting three-dimensional models, multi-physics field coupling simulation technology, high-quality grid division, and full consideration of external environmental factors, providing important support for the safe operation, design optimization and conductor maintenance of power systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below in conjunction with the accompanying drawings and implementation examples: Figure 1 It is a simulation flow chart of the present invention; Figure 2 It is the main interface of ANSYS software; Figure 3 is the number of layers of the conductor cross-section structure in Embodiment 2 of the present invention; Figure 4 The wire material property setting interface in Embodiment 2 of the present invention; Figure 5 The three-dimensional model of the conductor in the second embodiment of the present invention is established; Figure 6 It is the boundary condition setting interface in embodiment 2 of the present invention; Figure 7 Determination of the wire calculation area in Embodiment 2 of the present invention; Figure 8 The wire grid division in Embodiment 2 of the present invention; Fig. 9 The cloud diagram of the overall temperature distribution of the conductor in Example 2 of the present invention; Fig.10 This is a cloud diagram of the radial temperature value distribution of the conductor in Example 2 of the present invention; Fig.11 This is a cloud diagram of the overall temperature value distribution of the LGJ 240 / 30 conductor in Example 3 of the present invention; Fig.12 This is a cloud diagram of radial temperature distribution of the LGJ 240 / 30 conductor in Example 3 of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments: Example 1 like Figure 1~2 As shown in the figure, the simulation method of the temperature field of the inner and outer layers of overhead transmission lines based on ANSYS ICEPAK comprehensively considers the influence of the current carrying capacity, heat conduction, heat convection, heat radiation, wind speed and solar radiation of the conductor strands during operation through ANSYS ICEPAK software, and is implemented in the following steps: Step 1: According to the structural parameters of the conductor, a three-dimensional solid model is established using modeling software, and the calculation area is defined in ANSYSICEPAK; Step 2: Define the solid material properties of each strand, set accurate boundary conditions, and perform high-quality meshing on the model; Step 3: Based on the operating conditions, calculate the heating rate of each part of the conductor and input the environmental parameters; Step 4: Set the iteration accuracy, solve the three-dimensional thermal-fluid coupling field, and obtain the temperature distribution of the wire under various working conditions; Step 5: When the calculation results converge within the set accuracy range, post-processing analysis is performed; Step 6: Output detailed data of the temperature field, including the temperature distribution cloud map, the minimum, maximum and average temperature of each layer of strands.

[0021] In this embodiment, the Step 1 uses modeling software to establish a three-dimensional solid model, and the modeling software includes but is not limited to SpaceClaim, DesignModeler, CAD and SolidWorks. At the same time, the three-dimensional model needs to be converted into a model recognized by ICEPAK. The specific implementation steps of the Step 1 include: Step 1.1: Set the number of strands in the next outer layer to n, take the axial direction of the strands in the center layer as the reference direction, and construct the corresponding surface through the diagonal of the rectangle formed by the side length of the regular n-gon inscribed in the circular cross-section at both ends of the strands, and use the surface as the winding angle amplitude of the next outer layer of strands; Step 1.2: Then, array and stretch the single strand model in the modeling software to obtain a wire model with a real winding angle.

[0022] Furthermore, the model in Step 1 is set such that the electrical conductivity and thermal conductivity of each strand material are uniform, linear and isotropic, the heat exchange between the outer strands and the surrounding air is thermal convection, the conductor is in an infinite space, and the influence of the electromagnetic field effect is ignored.

[0023] Furthermore, in the process of defining the calculation area in ANSYS ICEPAK in Step 1, two planes along the axial direction of the conductor are set to be closed, and four planes along the radial direction of the conductor are set to be open, so as to apply wind speed to the conductor.

[0024] Furthermore, the Step 2 meshing adopts the Mesher HD tool to generate a hybrid mesh, including hexahedral mesh, prismatic mesh and tetrahedral mesh. Local mesh refinement is adopted in key areas (such as heat source, boundary layer, etc.), and quality inspection is performed by the Skewness method to ensure that the mesh meets the requirements of subsequent simulation analysis.

[0025] Furthermore, when defining the solid material properties of each strand in Step 2, the material properties include density and specific heat capacity. If marked in the parameter table of the conductor nameplate, the nameplate shall prevail; if not marked, set it.

[0026] Furthermore, the environmental parameters in Step 3 include wind speed, wind direction, solar radiation intensity, solar heat absorption coefficient, radiation heat dissipation coefficient and ambient temperature.

[0027] Furthermore, the heating rate of each part of the wire is calculated in Step 3, and the Joule heat continuously generated by the wire is calculated to simulate the heat source of the wire. It is directly input in the interface of defining the wire properties. Taking steel wire and aluminum wire as examples, the ratio of the current passing through the steel wire and the aluminum wire is: (1); The heat generation rate per unit volume of steel strands is: (2); The heat generation rate per unit volume of aluminum strands is: (3); In the formula, , Respectively represent the current passing through the steel strand and the aluminum strand, the unit is A; , Respectively represent the resistance of steel strands and aluminum strands, in Ω; , Respectively represent the resistivity of steel strands and aluminum strands, in units of (Ω·m); , Respectively represent the radial cross-sectional area of ​​steel strands and aluminum strands, in m 2 ; , Respectively represent the volume of steel strands and aluminum strands, the unit is m³.

[0028] Furthermore, the iteration accuracy in Step 4 is set according to engineering requirements.

[0029] Furthermore, in Step 6, the heat-flux coupled temperature field solved by ANSYS ICEPAK can output detailed data of the temperature field, including a temperature distribution cloud diagram, and the minimum, maximum, and average temperature of each layer of strands.

[0030] In the preferred solution, the environmental parameters are input in Step 3. The solar absorption coefficient and radiation heat dissipation coefficient of the conductor surface are generally approximately equal. The bright new conductor takes 0.23-0.43, and the blackened old wire usually takes 0.90-0.95. If there is a clear mark in the actual parameter table of the conductor, the specific nameplate shall prevail; the solar radiation intensity is generally 1000W / m², but in some special specific applications, it can be adjusted according to the solar sunshine curve to adapt to the actual situation under different climatic conditions.

[0031] Example 2 In another preferred embodiment, based on the above embodiment 1, Figure 1 As shown, the method for simulating the temperature field of the inner and outer layers of an overhead transmission line based on ANSYS ICEPAK provided by the present invention comprehensively considers the influence of the current carrying capacity, heat conduction, heat convection, heat radiation, wind speed and solar radiation of the conductor strands during operation through ANSYS ICEPAK software, and is implemented in the following steps: Step 1: According to the structural parameters of the conductor, a three-dimensional solid model is established using modeling software, and the calculation area is defined in ANSYSICEPAK; Step 2: Define the solid material properties of each strand, set accurate boundary conditions, and perform high-quality meshing on the model; Step 3: Based on the operating conditions, calculate the heating rate of each part of the conductor and input environmental parameters (including wind speed, wind direction, solar radiation intensity, solar heat absorption coefficient, radiation heat dissipation coefficient and ambient temperature); Step 4: Set the iteration accuracy (usually ), solve the three-dimensional thermal-fluid coupling field and obtain the temperature distribution of the wire under various working conditions; Step 5: When the calculation results converge within the set accuracy range, post-processing analysis is performed; Step 6: Output detailed data of the temperature field, including the temperature distribution cloud map, the minimum, maximum and average temperature of each layer of strands.

[0032] In the modeling process of Step 1, the software used includes but is not limited to SpaceClaim, DesignModeler, CAD and SolidWorks. If the above software is not built-in ANSYS, the 3D model needs to be converted into the mode approved by ICEPAK. In addition, in order to accurately simulate the winding angle of the wire, the following steps are adopted: Set the number of strands of the next outer layer to n , taking the axial direction of the center layer strand as the reference direction, the inscribed right angles of the circular cross-sections at both ends of the strands are nThe diagonal lines of the rectangle formed by the side lengths of the polygons construct the corresponding curved surface, and the curved surface is used as the winding angle amplitude of the next outer layer of strands; then, the single strand model is arrayed and stretched in the modeling software to obtain a wire model with a real winding angle.

[0033] With reference to Round Wire Concentric Stranded Overhead Conductors (GB / T 1179-2017), the following assumptions are made for the model: (1) The electrical conductivity and thermal conductivity of each strand of wire material are uniform, linear and isotropic; (2) The heat exchange between the outer aluminum strands and the surrounding air is through convection; (3) The wire is in an infinite space and the influence of electromagnetic field effects is ignored.

[0034] Furthermore, in the process of defining the calculation area in Step 1, two planes along the axial direction of the conductor are set to be closed, and four planes along the radial direction of the conductor are set to be open, so as to apply wind speed to the conductor.

[0035] Furthermore, when defining the solid material properties of each strand in Step 2, the main parameters are generally: (1) The density of aluminum is 2700 kg / m³, the specific heat capacity is 880 J / (kg·K), and the thermal conductivity is 226 W / (m·K); (2) The density of steel is 7900 kg / m³, the specific heat capacity is 460 J / (kg·K), and the thermal conductivity is 45 W / (m·K); Furthermore, the meshing in Step 2 is performed using the Mesher HD tool, which can generate hybrid meshes (including hexahedral meshes, prismatic meshes, and tetrahedral meshes); local mesh refinement is used in key areas (such as heat sources, boundary layers, etc.), and quality inspection is performed using the Skewness method to ensure that the mesh meets the requirements of subsequent simulation analysis.

[0036] Furthermore, in the Step 3, the Joule heat continuously generated by the wire is calculated to simulate the heat source of the wire, which is directly input in the interface for defining the wire properties; the ratio of the current passing through the steel wire and the aluminum wire is: (1) The heat generation rate per unit volume of steel strands is: (2) The heat generation rate per unit volume of aluminum strands is: (3).

[0037] Furthermore, in the step 3, the environmental parameters are inputted. The solar absorption coefficient and radiation heat dissipation coefficient of the conductor surface are generally taken to be approximately equal. The bright new conductor takes 0.23 to 0.43, and the blackened old wire usually takes 0.90 to 0.95. If there is a clear mark in the actual parameter table of the conductor, the specific nameplate shall prevail. The solar radiation intensity is generally 1000W / m³, but in some special specific applications, it can be adjusted according to the solar sunshine curve to adapt to the actual situation under different climatic conditions.

[0038] Furthermore, in the Step 6, the heat-flux coupled temperature field solved by ANSYS ICEPAK can output detailed data of the temperature field, including a temperature distribution cloud diagram, and the minimum, maximum, and average temperature of each layer of strands.

[0039] Example 3 In another preferred embodiment, based on the above embodiment 2, please refer to the attached Figure 1 The calculation flow chart of the present invention takes JLHA1 / G6A-500 / 280 conductor as an example to illustrate the specific application of the present method: (1) Establishing a 3D model The main interface of ANSYS software is as follows Figure 2 As shown in the figure, the JLHA1 / G6A-500 / 280 conductor has 6 layers of strands, including 4 layers of steel strands and 2 layers of aluminum strands, which are used to set the material properties of the strands. Figure 3 As shown, the relevant technical parameters are listed in Table 1, the lay direction and lay pitch ratio are listed in Table 2, and the material properties are set as follows Figure 4 The model building results are as follows Figure 5 shown.

[0040]

[0041]

[0042] (2) Setting the boundary conditions of the model When defining the calculation area, the two planes along the axial direction of the conductor are set to be closed, and the four planes along the radial direction of the conductor are set to be open, so that the wind speed can be applied to the radial direction of the conductor. Figure 6 As shown, Figure 7 The three-dimensional space formed by the blue lines is the simulation calculation area.

[0043] (3) Grid division The finite element meshing results of the wire model are as follows: Figure 8 As shown in the figure, the wire is divided into 3661772 units and 2860290 nodes in the computational domain. After the meshing is completed, the Skewness method is used to check the mesh quality to ensure that the mesh quality meets the requirements of subsequent finite element analysis.

[0044] (4) Calculate the heat generation rate of the strand The ratio of the current passing through the steel strand and the aluminum strand is: (1) The heat generation rate per unit volume of steel strands is: (2) The heat generation rate per unit volume of aluminum strands is: (3).

[0045] In the formula, I 1. I 2 represents the current passing through the steel strand and the aluminum strand. In this simulation, the total current is taken I =500A; other values ​​can be obtained according to Table 1.

[0046] (5) Input environmental parameters The wind speed is set to 1m / s, the wind direction is horizontally to the right along the X-axis, the ambient temperature is 20℃, the current carrying capacity of the wire is 500A, the solar absorption coefficient and radiation heat dissipation coefficient of the material surface are both 0.9, and the solar radiation intensity is 1000W / m 2 .

[0047] (6) Temperature calculation and verification The wire temperature result obtained is as follows: Fig. 9 And as shown in Table 3.

[0048]

[0049] From the comparison results in Table 3, the temperature errors of all levels are within 5%, which shows that the simulation method has high accuracy and can better reflect the temperature distribution of the wire.

[0050] Example 4 In order to further verify the effectiveness of the method of the present invention, based on Example 3, the LGJ 240 / 30 conductor is taken as an example, and its technical parameters are shown in Table 4; the calculation results of the radial temperature of the conductor are shown in Table 5, and the conductor temperature distribution cloud diagram is shown in Table 6. Fig.10 shown.

[0051]

[0052]

[0053] According to Table 5 in Example 4, the relative error of the temperature of the LGJ 240 / 30 conductor is very small compared with the experimental measurement value, with a maximum error of 2.7% and a minimum error of only 0.1%. Therefore, the simulation method can accurately reflect the temperature change of the conductor during operation. The method mentioned in the present invention can accurately predict the temperature distribution of overhead transmission lines under different working conditions, and can provide an important theoretical basis for the operation safety, design optimization and conductor maintenance of the power system.

[0054] In the preferred solution, the model in Step 1 is set so that the electrical conductivity and thermal conductivity of each strand material are uniform, linear and isotropic, the heat exchange between the outer strands and the surrounding air is thermal convection, the wire is in an infinite space, and the influence of the electromagnetic field effect is ignored; the above settings are intended to simplify the heat conduction analysis process and improve calculation efficiency; Step 2 will introduce a temperature gradient to simulate the temperature rise of the wire when current passes through, while considering the thermal expansion coefficient of the material to evaluate the influence of thermal stress on the stability of the wire structure.

[0055] In the preferred solution, in the process of delimiting the calculation area in ANSYS ICEPAK in Step 1, the two planes along the axial direction of the wire are set to be closed, and the four planes along the radial direction of the wire are set to be open, so as to apply wind speed to the wire; the above settings can simulate the influence of wind force on the wire in the actual environment and improve the accuracy of the simulation; at the same time, in Step 2, the turbulence model will be used to further refine the distribution of the wind flow field to ensure the precision and reliability of the calculation results.

[0056] In the preferred solution, the meshing in Step 2 is performed using the Mesher HD tool to generate a hybrid mesh, including a hexahedral mesh, a prismatic mesh, and a tetrahedral mesh. Local mesh refinement is performed in key areas, and quality inspection is performed using the Skewness method to ensure that the mesh meets the requirements of subsequent simulation analysis. The above settings can effectively improve calculation accuracy and efficiency. In Step 3, CFD (Computational Fluid Dynamics) simulation software is used to simulate the flow field of the model, analyze the fluid flow characteristics, and verify the accuracy of the model in combination with experimental results, providing a reliable basis for subsequent optimization design.

[0057] In summary, the method for simulating the temperature field of the inner and outer layers of overhead transmission lines based on ANSYS ICEPAK provided by the present invention successfully solves the shortcomings of the temperature field simulation of overhead transmission lines in terms of accuracy, scope of application and consideration of external environmental factors, and has made breakthroughs in the field of three-dimensional temperature field simulation. The present invention innovatively expands the ANSYS ICEPAK software, a tool commonly used for thermal design simulation of electronic equipment, to the field of power transmission for the first time, and performs accurate simulation of the three-dimensional temperature field of overhead transmission lines. During the simulation process, the present invention not only carefully considers the geometric structure and material properties of the conductor itself, but also fully incorporates the comprehensive influence of operating conditions (such as current carrying capacity) and external environmental factors (such as wind speed, solar radiation, etc.). This comprehensive and detailed consideration method is not common in previous conductor temperature field simulations, thereby significantly improving the novelty and practicality of the simulation results. Through high-precision three-dimensional solid modeling and high-quality meshing, the present invention realizes accurate simulation of the temperature field of the inner and outer layers of the conductor. Compared with traditional two-dimensional simulation or steady-state heat conduction model, this method is not only more accurate, but also has a wider range of applications. In addition, the present invention combines ANSYS The powerful functions of ICEPAK software and the actual needs in the field of power transmission, through a series of innovative methods and technical means, such as three-dimensional solid modeling, precise boundary condition setting, high-quality mesh division and heat rate calculation based on operating conditions, together constitute the core technical innovation of the present invention; the application and implementation of the present invention provides a new means for evaluating the temperature distribution and operating status of overhead transmission lines. Through simulation analysis, the temperature changes of the wires under different working conditions can be intuitively grasped, thereby providing strong technical support for the safe operation, design optimization and maintenance of the wires; this application innovation not only greatly improves the reliability and safety of the power transmission system, but also effectively reduces the operation and maintenance costs and time costs; at the same time, this innovative technology has also injected new vitality into the construction and development of smart grids, and promoted the power transmission technology to move towards a more efficient and intelligent direction, with far-reaching social and economic benefits and industry leading role.

Claims

1. The simulation method of the temperature field of the inner and outer layers of overhead transmission lines based on ANSYS ICEPAK is characterized by: The influence of current carrying capacity, heat conduction, heat convection, heat radiation, wind speed and solar radiation of the conductor strands during operation is comprehensively considered by ANSYSICEPAK software, and the following steps are implemented: Step 1: According to the structural parameters of the conductor, a three-dimensional solid model is established using modeling software, and the calculation area is defined in ANSYS ICEPAK; Step 2: Define the solid material properties of each strand, set accurate boundary conditions, and perform high-quality meshing on the model; Step 3: Based on the operating conditions, calculate the heating rate of each part of the conductor and input the environmental parameters; Step 4: Set the iteration accuracy, solve the three-dimensional thermal-fluid coupling field, and obtain the temperature distribution of the wire under various working conditions; Step 5: When the calculation results converge within the set accuracy range, post-processing analysis is performed; Step 6: Output detailed data of the temperature field, including the temperature distribution cloud map, the minimum, maximum and average temperature of each layer of strands.

2. The method for simulating the temperature field of inner and outer layers of overhead power transmission lines based on ANSYS ICEPAK according to claim 1, characterized in that: The Step 1 uses modeling software to establish a three-dimensional solid model. The modeling software includes but is not limited to SpaceClaim, DesignModeler, CAD and SolidWorks. At the same time, the three-dimensional model needs to be converted into a model recognized by ICEPAK. The specific implementation steps of the Step 1 include: Step 1.1: Set the number of strands in the next outer layer to n, take the axial direction of the strands in the center layer as the reference direction, and construct the corresponding surface through the diagonal of the rectangle formed by the side length of the regular n-gon inscribed in the circular cross-section at both ends of the strands, and use the surface as the winding angle amplitude of the next outer layer of strands; Step 1.2: Then, array and stretch the single strand model in the modeling software to obtain a wire model with a real winding angle.

3. The method for simulating the temperature field of inner and outer layers of overhead power transmission lines based on ANSYS ICEPAK according to claim 2, characterized in that: The model in Step 1 is set as follows: the electrical conductivity and thermal conductivity of each strand material are uniform, linear and isotropic; the heat exchange between the outer strands and the surrounding air is thermal convection; the conductor is in an infinite space; and the influence of the electromagnetic field effect is ignored.

4. The method for simulating the temperature field of inner and outer layers of overhead power transmission lines based on ANSYS ICEPAK according to claim 3 is characterized in that: In the process of defining the calculation area in ANSYS ICEPAK in Step 1, two planes along the axial direction of the wire are set to be closed, and four planes along the radial direction of the wire are set to be open, so as to apply wind speed to the wire.

5. The method for simulating the temperature field of inner and outer layers of overhead power transmission lines based on ANSYS ICEPAK according to claim 4, characterized in that: The Step 2 meshing uses the Mesher HD tool to generate a hybrid mesh, including hexahedral meshes, prismatic meshes, and tetrahedral meshes. Local mesh refinement is used in key areas, and quality inspection is performed using the Skewness method to ensure that the mesh meets the requirements of subsequent simulation analysis.

6. The method for simulating the temperature field of inner and outer layers of overhead power transmission lines based on ANSYS ICEPAK according to claim 5, characterized in that: When defining the solid material properties of each strand in Step 2, the material properties include density and specific heat capacity. If marked in the parameter table of the conductor nameplate, the nameplate shall prevail; if not marked, set it.

7. The method for simulating the temperature field of inner and outer layers of overhead power transmission lines based on ANSYS ICEPAK according to claim 6, characterized in that: The environmental parameters in Step 3 include wind speed, wind direction, solar radiation intensity, solar heat absorption coefficient, radiation heat dissipation coefficient and ambient temperature.

8. The method for simulating the temperature field of inner and outer layers of overhead power transmission lines based on ANSYS ICEPAK according to claim 7, characterized in that: In the Step 3, the heating rate of each part of the wire is calculated. The Joule heat continuously generated by the wire is calculated to simulate the heat source of the wire. It is directly input in the interface of defining the wire properties. Taking steel wire and aluminum wire as examples, the ratio of the current passing through the steel wire and the aluminum wire is: （1）； The heat generation rate per unit volume of steel strands is: （2）； The heat generation rate per unit volume of aluminum strands is: （3）； In the formula, , Represent the current passing through the steel strand and the aluminum strand respectively; , represent the resistance of steel strands and aluminum strands respectively; , represent the resistivity of steel strands and aluminum strands, respectively; , Respectively represent the radial cross-sectional areas of the steel strand and the aluminum strand; , Represent the volumes of steel strands and aluminum strands respectively.

9. The method for simulating the temperature field of inner and outer layers of overhead power transmission lines based on ANSYS ICEPAK according to claim 8, characterized in that: The iteration accuracy in Step 4 is set according to engineering requirements.

10. The method for simulating the temperature field of inner and outer layers of overhead power transmission lines based on ANSYS ICEPAK according to claim 9, characterized in that: In the Step 6, the heat-flux coupled temperature field solved by ANSYS ICEPAK can output detailed data of the temperature field, including a temperature distribution cloud diagram, and the minimum, maximum, and average temperatures of each layer of strands.

Images