Cooling capacity-increasing overhead conductor, dynamic ampacity determination method, medium and device

Abstract

The application provides a cooling and capacity-increasing overhead conductor, a dynamic ampacity determination method, a medium and equipment, and relates to the technical field of power transmission lines.The method sets the overhead conductor to adopt a three-layer composite structure, the outer layer is a passive cooling coating, the thickness is 50-200 mu m, the surface has micro-nano structures for enhancing mid-infrared radiation, the emissivity is greater than or equal to 0.92, and the contact angle is greater than 120 degrees after hydrophobic modification treatment;the intermediate layer is a high-conductivity aluminum alloy conductor layer, and the inner layer is a high-strength galvanized steel core;the coating and the conductor layer form a directional heat conduction path through a gradient thermal conductivity material, and the thermal conductivity coefficient of the gradient material increases from the coating to the conductor layer;the coating is coated in an axial segmented coating or a reticular coating manner.The overhead conductor can effectively increase the ampacity of the line and optimize the power transmission design of the line, and the dynamic ampacity determination method can obtain a quantitative index of the capacity-increasing effect.

Description

Technical Field

[0001] This invention relates to the field of power transmission line technology, and in particular to a cooling and capacity-enhancing overhead conductor, a method for determining dynamic current carrying capacity, a medium, and equipment. Background Technology

[0002] Traditional overhead conductors primarily use aluminum steel-cored stranded wire (ACSR), whose current-carrying capacity is limited by conductor temperature rise and environmental heat dissipation conditions. Existing capacity expansion methods mostly involve increasing the conductor cross-sectional area or replacing with high-temperature resistant conductors, but these methods suffer from high costs and complex construction. The industry-standard capacity expansion solutions have significant limitations: increasing the conductor cross-sectional area requires replacing the entire conductor section and upgrading the tower structure, increasing engineering costs by 30%-50%; while using heat-resistant aluminum alloy conductors can raise the operating temperature to 150℃, the material cost is 2-3 times higher than conventional conductors, and long-term high-temperature operation accelerates steel core oxidation and corrosion. Although passive cooling coating technology can reduce temperature rise through radiative heat dissipation, existing coating processes suffer from uneven application, unclear impact on mechanical properties, and mismatched current-carrying capacity calculation models. Furthermore, the synergistic effect of the coating, conductor, and steel core has not yet formed a systematic technical solution, lacking standardized processes and quantitative evaluation methods for capacity expansion effects. Summary of the Invention

[0003] The purpose of this invention is to provide a cooling and capacity-enhancing overhead conductor, a method for determining dynamic current-carrying capacity, a medium, and equipment, aiming to achieve temperature rise suppression and current-carrying capacity enhancement, and to establish a corresponding current-carrying capacity calculation model and a method for evaluating the capacity enhancement effect. The specific technical solution is as follows:

[0004] A cooling and capacity-enhancing overhead conductor is disclosed, comprising a three-layer composite structure. The outer layer is a passive cooling coating with a thickness of 50-200 μm and a micro / nano structure on its surface that enhances mid-infrared radiation, with an emissivity ≥0.92, and is hydrophobically modified to achieve a contact angle >120°. The middle layer is a high-conductivity aluminum alloy conductor layer, and the inner layer is a high-strength galvanized steel core. A directional heat conduction path is formed between the coating and the conductor layer through a gradient thermally conductive material, wherein the thermal conductivity of the gradient material increases from the coating to the conductor layer. The coating is applied in an axial segmented coating or a mesh coating manner.

[0005] Furthermore, the axial segmented coating method is as follows: periodic coating units are set along the axial direction of the conductor, each cycle includes a 20cm long coated area and a 10cm long uncoated area. The coated area is fully covered circumferentially, and the uncoated area exposes the conductor layer circumferentially. The coating cycle repeats to cover the entire length of the conductor.

[0006] Furthermore, the mesh coating method is as follows: a square mesh with a side length of 5mm is formed on the surface of the conductor, the mesh line width is 1mm, the coating thickness at the mesh intersection is 1.2-1.5 times the thickness of the edge area, and the area of ​​the uncoated area accounts for 76%.

[0007] Furthermore, a flexible transition layer is provided at the interface between the coating and the conductor layer, and its elastic modulus is 20%-30% of that of the coating material.

[0008] Furthermore, the intersections of the mesh coating are rounded with a radius ≥ 0.2 mm.

[0009] This invention also provides a method for determining the dynamic current carrying capacity of a cooling and capacity-enhancing overhead conductor, comprising the following steps:

[0010] S100. Perform geometric modeling on the overhead conductor;

[0011] S200, Correction of the heat conduction model:

[0012] Calculation of equivalent emissivity for non-uniform coating:

[0013] ε eff =η*ε coating +(1-η)*ε bare

[0014] Where, ε eff For the equivalent emissivity, ε coating The emissivity of the coating is 0.92, ε bare The emissivity of the bare conductor is 0.3.

[0015] Calculation of equivalent convective heat transfer coefficient:

[0016] h conv，eff =η*h coating +(1-η)*h bare

[0017] Among them, h conv，eff h is the equivalent convective heat transfer coefficient. coating This is the convection correction factor for the coating surface. h bare h is the standard convection coefficient for bare conductors. bare = 5.6 + 3.8v, where v represents wind speed;

[0018] S300, Correction of the heat conduction equation:

[0019] The three-dimensional non-uniform heat conduction equation is as follows:

[0020]

[0021] Where k(x, y, z) is the spatially distributed thermal conductivity, taking the thermal conductivity of the coating in the coated area and the thermal conductivity of the bare wire in the uncoated area, ρ is the mass density of the object, and c p Q is the specific heat capacity of the object, T is the temperature, and Q is the temperature.joule The rate of Joule heat generation per unit volume;

[0022] S400, Constructing the finite element model:

[0023] Import the 3D CAD model of the conductor;

[0024] Creating coating geometry: For axial segmented coating, use periodic Boolean operations to cut the surface; for mesh coating, generate the mesh by cutting with intersecting lines.

[0025] Assign material properties to the coating area;

[0026] Define boundary conditions;

[0027] S600, Dynamic Load Capacity Optimization:

[0028] The maximum current that a conductor can withstand is determined using the equivalent heat dissipation area method, and the calculation formula is as follows:

[0029]

[0030] Among them, I max I is the maximum current that a conductor can withstand under conditions of uneven current distribution. uniform A is the current that a conductor can withstand when the current is uniformly distributed. eff For the actual effective heat dissipation area, A eff =η*A coating +(1-η)A bare A coating For the area of ​​the coating, A bare Let A be the area of ​​the bare conductor. uniform This is the reference heat dissipation area under uniform heat dissipation conditions;

[0031] The dynamic carrying capacity is determined based on an iterative algorithm, including the following steps:

[0032] S610, Input environmental parameters include ambient temperature T air The parameters include wind speed v, heat dissipation area S of overhead conductors, and coating parameters including coating cycle number n and convective heat transfer coefficient h between overhead conductors and air.

[0033] S620. Calculate the Joule heat Q under the current I. joule =I 2 R, where R is the resistance;

[0034] S630. Solve the non-uniform heat conduction equation to obtain the highest temperature T. max ;

[0035] S640, Comparison T max With limiting temperature T limit The size of T, if Tmax >T limit Calculate the new current by proportionally reducing the current.

[0036] S650, change the new current I new Replace the current I and return to step S620, iterating until |T max -T limit If | < 1℃, output the new current I. new As dynamic load capacity.

[0037] Furthermore, for axially segmented coated overhead conductors, the geometric definition is as follows: along the conductor's axial direction, the surface is divided into periodic units, with each period lasting 30 cm. Within each period, the coated area is 20 cm long, and the uncoated area is 10 cm long, with uniform full coating in the circumferential direction; parametrically represented as: coating coverage. Coating thickness h c =100μm;

[0038] For a mesh-coated overhead conductor with partial grid coverage, the geometric definition is: a square grid with a surface coating side length L = 5 mm and a line width w = 1 mm; parametrically represented as: coating coverage. Coating thickness h c =100μm.

[0039] Furthermore, the method also includes the following steps:

[0040] S700, Thermal Stress Calculation and Analysis:

[0041] Modeling of local thermal expansion differences;

[0042] Temperature field input: Import the temperature distribution T(x, y, z) calculated by the heat conduction model into the structural mechanics module;

[0043] The formula for calculating thermal strain is as follows:

[0044] ε thermal =α*(TT) ref )

[0045] Where, ε thermal The coefficient of thermal expansion is α, which is the linear coefficient of thermal expansion and is taken as 8-10 for coatings. 6 K -1 For bare conductors, the value is 23*10. -6 K -1 T ref For reference temperature;

[0046] The formula for calculating the stress concentration factor is as follows:

[0047]

[0048] Among them, K t ρ is the stress concentration factor, α′ is the size of the coating edge defect, and ρ′ is the radius of curvature.

[0049] Finite element stress simulation: The contact is set to a non-slip bonded contact between the coating and the conductor interface, and the mesh is refined at the coating edge and mesh intersection, with a minimum element size of 0.1 mm.

[0050] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for determining the dynamic current carrying capacity of a cooling and capacity-increasing overhead conductor as described above.

[0051] The present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the method for determining the dynamic current carrying capacity of the cooling and capacity-increasing overhead conductor as described above.

[0052] The present invention provides a cooling and capacity-enhancing overhead conductor, a method for determining dynamic current carrying capacity, a medium, and equipment, which have the following beneficial effects:

[0053] (1) This invention employs a three-layer composite structure for the overhead conductor. The outer layer is a passive cooling coating with a thickness of 50-200 μm. Its surface has a micro / nano structure that enhances mid-infrared radiation, with an emissivity ≥0.92, and is hydrophobically modified to achieve a contact angle >120°. The middle layer is a high-conductivity aluminum alloy conductor layer, and the inner layer is a high-strength galvanized steel core. A directional heat conduction path is formed between the coating and the conductor layer through a gradient thermal conductivity material, with the thermal conductivity of the gradient material increasing from the coating to the conductor layer. The coating is applied using axial segmented coating or mesh coating. This overhead conductor effectively increases the current-carrying capacity of the line, optimizes the transmission design, and has the following advantages: It enables distributed temperature measurement using existing overhead transmission line monitoring devices, effectively reducing equipment costs and simplifying maintenance procedures. Its simplified hardware structure reduces maintenance difficulty and cost. Simultaneously, through precise temperature monitoring and dynamic adjustment of heat dissipation efficiency, it significantly improves the reliability of the power grid and avoids faults caused by overheating. In addition, this overhead conductor has wide applicability, can adapt to various environments, fully utilize the potential of transmission lines, can increase the average annual current carrying capacity of transmission lines by 15-25%, significantly reduce conductor temperature rise and sag changes, and provide a better solution for the intelligent transformation of UHV power grids.

[0054] (2) This invention constructs a finite element model by geometrically modeling the overhead conductor, correcting the heat conduction model and the heat conduction equation, and dynamically optimizing the current carrying capacity. The maximum current that the conductor can withstand is determined by the equivalent heat dissipation area method, and the dynamic current carrying capacity is determined by the iterative algorithm. Based on theoretical calculation results and actual operating data, the current carrying capacity and temperature rise characteristics of the conductor before and after coating are compared, and a quantitative index of the capacity enhancement effect can be obtained. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the structure of the cooling and capacity-enhancing overhead conductor with axial segmented coating according to the present invention;

[0056] Figure 2 This is a schematic diagram of the structure of the cooling and capacity-enhancing overhead conductor with mesh coating of the present invention;

[0057] Figure 3 This is a structural block diagram of a computer device according to an embodiment of the present invention. Detailed Implementation

[0058] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clearly illustrate the purpose of the embodiments of the present invention.

[0059] Example 1

[0060] This embodiment provides a cooling and capacity-enhancing overhead conductor. The overhead conductor adopts a three-layer composite structure. The outer layer is a passive cooling coating with a thickness of 50-200μm. The surface has a micro-nano structure that enhances mid-infrared radiation, with an emissivity ≥0.92, and is hydrophobically modified to achieve a contact angle >120°. The middle layer is a high-conductivity aluminum alloy conductor layer, and the inner layer is a high-strength galvanized steel core. A directional heat conduction path is formed between the coating and the conductor layer through a gradient thermally conductive material. The thermal conductivity of the gradient material increases from the coating to the conductor layer. The coating is applied in an axial segmented coating or a mesh coating manner.

[0061] This embodiment determines the relationship between the coating thickness of the passive cooling material and its cooling effect, as well as the optimal coating method, by combining numerical simulation and field testing. The coating method is gradually changed, and the temperature rise of the conductor is observed and recorded. A curve showing the relationship between the coating method and the conductor temperature rise is plotted to determine the trend of decreasing conductor temperature rise under different coating methods within a certain range, and the situation where the cooling effect tends to saturate when the coating thickness reaches a certain critical value. Based on the test results of different types of transmission conductors, the optimal coating method for each is determined.

[0062] Monitoring shows that this overhead conductor can effectively increase the current carrying capacity of the line, optimize the transmission design, and has the following advantages: It can efficiently utilize existing overhead transmission line monitoring devices for distributed temperature measurement, effectively reducing equipment costs and simplifying maintenance procedures. Its simplified hardware structure reduces maintenance difficulty and cost. Simultaneously, through precise temperature monitoring and dynamic adjustment of heat dissipation efficiency, it significantly improves the reliability of the power grid and avoids faults caused by overheating. Furthermore, this overhead conductor has wide applicability, can adapt to various environments, fully utilizes the potential of the transmission line, can increase the average annual current carrying capacity of the transmission line by 15-25%, significantly reduces conductor temperature rise and sag changes, and provides a better solution for the intelligent transformation of UHV power grids.

[0063] In one embodiment, see Appendix Figure 1 As shown, the axial segmented coating method is as follows: periodic coating units are set along the axial direction of the conductor. Each cycle includes a 20cm long coated area and a 10cm long uncoated area. The coated area is fully covered circumferentially, and the uncoated area exposes the conductor layer circumferentially. The coating cycle repeats to cover the entire length of the conductor.

[0064] In one embodiment, see Appendix Figure 2 As shown, the mesh coating method is as follows: a square mesh with a side length of 5mm is formed on the surface of the conductor, the mesh line width is 1mm, the coating thickness at the mesh intersection is 1.2-1.5 times the thickness of the edge area, and the area of ​​the uncoated area accounts for 76%.

[0065] In a preferred embodiment, a flexible transition layer with an elastic modulus of 20%-30% of the coating material is provided at the interface between the coating and the conductor layer; the intersections of the mesh coating are rounded with a radius ≥0.2mm; and the stress distribution at the edge of the coating area is optimized through finite element simulation to ensure that the local maximum stress is ≤200MPa. In this embodiment, the above measures can suppress thermal stress concentration.

[0066] Example 2

[0067] This embodiment provides a method for determining the dynamic current carrying capacity of a cooling and capacity-enhancing overhead conductor, including the following steps:

[0068] S100, Perform geometric modeling of overhead conductors.

[0069] For details, please refer to the appendix. Figure 1 As shown, for an axially segmented coated overhead conductor with 1 / 3 of its length uncoated and 2 / 3 of its length coated, the geometric definition is as follows: along the conductor's axis, the surface is divided into periodic units, with each period being 30cm. Within each period, the coated area is 20cm long and the uncoated area is 10cm long, with uniform full coating in the circumferential direction; parametrically represented as: coating coverage. Coating thickness h c =100μm.

[0070] See appendix Figure 2 As shown, for a mesh-coated overhead conductor with partial mesh coverage, the geometric definition is: a square mesh with a surface coating side length L = 5 mm and a line width w = 1 mm; parametrically represented as: coating coverage. Coating thickness h c =100μm.

[0071] S200, Correction of the heat conduction model:

[0072] Calculation of equivalent emissivity for non-uniform coating:

[0073] ε eff =η*ε coating +(1-η)*ε bare

[0074] Where, ε eff For the equivalent emissivity, ε coating The emissivity of the coating is 0.92, ε bare The emissivity of the bare conductor is 0.3.

[0075] Calculation of equivalent convective heat transfer coefficient:

[0076] h conv，eff =η*h coating +(1-η)*h bare

[0077] Among them, h conv,eff h is the equivalent convective heat transfer coefficient. coating This is the convection correction factor for the coating surface. h bare h is the standard convection coefficient for bare conductors. bare =5.6 + 3.8v, where v represents wind speed.

[0078] S300, Correction of the heat conduction equation:

[0079] The three-dimensional non-uniform heat conduction equation is as follows:

[0080]

[0081] Where k(x, y, z) is the spatially distributed thermal conductivity, taking the thermal conductivity of the coating in the coated area and the thermal conductivity of the bare wire in the uncoated area, ρ is the mass density of the object, and c p Q is the specific heat capacity of the object, T is the temperature, and Q is the temperature. joule This represents the Joule heat generation rate per unit volume.

[0082] S400, Constructing the finite element model:

[0083] Import a 3D CAD model of a conductor, such as an overhead conductor with a diameter D = 20mm and a length L = 1m;

[0084] Creating coating geometry: For axial segmented coating, use periodic Boolean operations to cut the surface; for mesh coating, generate the mesh by cutting with intersecting lines.

[0085] Assign material properties to the coating area;

[0086] Example of %COMSOL material parameters

[0087] material('coating').propertyGroup('def').set('thermal_conductivity',0.5);%W / (m·K)

[0088] material('coating').propertyGroup('def').set('emissivity',0.92);

[0089] Define boundary conditions;

[0090] % Radiation boundary conditions (coated area only)

[0091] surface1=mphgetselection(model.geom('geom1').feature('surf1'));

[0092] model.physics('ht').feature('rad1').selection.set(surface1);

[0093] model.physics('ht').feature('rad1').set('SurfaceEmissivity',0.92);

[0094] S600, Dynamic Load Capacity Optimization:

[0095] The maximum current that a conductor can withstand is determined using the equivalent heat dissipation area method, and the calculation formula is as follows:

[0096]

[0097] Among them, I max I is the maximum current that a conductor can withstand under conditions of uneven current distribution. uniform A is the current that a conductor can withstand when the current is uniformly distributed. effFor the actual effective heat dissipation area, A eff =η*A coating +(1-η)A bare A coating For the area of ​​the coating, A bare Let A be the area of ​​the bare conductor. uniform This is the reference heat dissipation area under uniform heat dissipation conditions;

[0098] The dynamic carrying capacity is determined based on an iterative algorithm, including the following steps:

[0099] S610, Input environmental parameters include ambient temperature T air The parameters include wind speed v, heat dissipation area S of overhead conductors, and coating parameters including coating cycle number n and convective heat transfer coefficient h between overhead conductors and air.

[0100] S620. Calculate the Joule heat Q under the current I. joule =I 2 R, where R is the resistance;

[0101] S630. Solve the non-uniform heat conduction equation to obtain the highest temperature T. max ;

[0102] S640, Comparison T max With limiting temperature T limit The size of T, if T max >T limit Calculate the new current by proportionally reducing the current.

[0103] S650, change the new current I new Replace the current I and return to step S620, iterating until |T max -T limit If | < 1℃, output the new current I. new As dynamic load capacity.

[0104] In one embodiment, the method further includes the following steps:

[0105] S700, Thermal Stress Calculation and Analysis:

[0106] Modeling of local thermal expansion differences;

[0107] Temperature field input: Import the temperature distribution T(x, y, z) calculated by the heat conduction model into the structural mechanics module;

[0108] The formula for calculating thermal strain is as follows:

[0109] ε thermal =α*(TT) ref )

[0110] Where, ε thermal The coefficient of thermal expansion is α, which is the linear coefficient of thermal expansion and is taken as 8-10 for coatings. 6 K -1 For bare conductors, the value is 23*10. -6 K -1 T ref The reference temperature can be selected as the initial state of the material or the temperature at which there is no thermal strain.

[0111] The formula for calculating the stress concentration factor is as follows:

[0112]

[0113] Among them, K t ρ is the stress concentration factor, α′ is the size of the coating edge defect, and ρ′ is the radius of curvature.

[0114] Finite element stress simulation: The contact is set as a non-slip bonded contact between the coating and the conductor interface, and the mesh is refined at the coating edge and mesh intersection, with a minimum element size of 0.1 mm.

[0115] Results Comparison

[0116] Coating method 1 / 3 unpainted + 2 / 3 coated Mesh coating (24% coverage) equivalent emissivity <![CDATA[ε eff =0.72]]> <![CDATA[ε eff =0.48]]> Increased carrying capacity 8.2％ 4.5％ Maximum stress (MPa) 152 (concentrated at the edge of the uncoated area) 218 (Stress concentration at grid intersections) Cost savings 33% of material costs 76% of material costs

[0117] Experimental verification

[0118] Infrared thermal imaging test: A high-resolution infrared camera (such as FLIR A8580) was used to image the surface temperature distribution of the conductor, and the simulated and measured temperature fields were compared. Temperature distribution uniformity index was calculated.

[0119]

[0120] Where U represents the uniformity of temperature distribution, σ T T represents the standard deviation of temperature. avg The average temperature is U>0.95, which is considered acceptable.

[0121] Stress measurement: Fiber Bragg grating (FBG) sensors are attached to the surface of the conductor to measure local strain. Allowable strain error range: Deviation between simulated and measured values ​​≤ 5%.

[0122] Since existing current-carrying capacity calculation models based on a two-layer steel-cored aluminum stranded wire structure are not entirely applicable to coated transmission conductors, this invention provides a refined model of the cross-section of a "coating-conductor-steel core" composite structure transmission conductor, accurately describing its geometric structure and material properties. Different current-carrying conditions are simulated in a laboratory environment, measuring parameters such as surface temperature rise, coating temperature distribution, and conductor stress changes. The experimental results are compared with simulation data to verify whether the influence of the coating material on conductor temperature rise is consistent with the simulation results. Taking an actual transmission line (such as a 500kV horizontally arranged AC transmission line in Hubei Province) as an example, passive cooling coatings of different thicknesses are applied to some phase conductors, with another phase used as a comparison. The established current-carrying capacity calculation model is used to calculate the conductor temperature of each phase under different currents, and the results are compared with the measured temperatures to verify the model's accuracy. Simultaneously, the factors influencing the current-carrying capacity of the composite structure transmission line are analyzed. Based on theoretical calculation results and actual operating data, comparing the current-carrying capacity and temperature rise characteristics of the conductors before and after coating allows for the quantification of the capacity enhancement effect.

[0123] Example 3

[0124] This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the dynamic current-carrying capacity determination method for cooling and capacity-increasing overhead conductors described above.

[0125] The storage medium may be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium may also include combinations of the above types of memory.

[0126] Example 4

[0127] This embodiment provides a computer device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps of the dynamic current carrying capacity determination method for cooling and capacity-increasing overhead conductors described above.

[0128] like Figure 3As shown, the computer device may include: at least one processor 71, such as a CPU (Central Processing Unit), at least one communication interface 73, memory 74, and at least one communication bus 72. The communication bus 72 is used to enable communication between these components. The communication interface 73 may include a display screen and a keyboard; optionally, the communication interface 73 may also include a standard wired interface or a wireless interface. The memory 74 may be high-speed RAM (Random Access Memory) or non-volatile memory, such as at least one disk storage device. Optionally, the memory 74 may also be at least one storage device located remotely from the aforementioned processor 71. The memory 74 stores application programs, and the processor 71 calls the program code stored in the memory 74 to execute any of the above-described method steps.

[0129] The communication bus 72 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The communication bus 72 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 3 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0130] The memory 74 may include volatile memory, such as random-access memory (RAM); the memory may also include non-volatile memory, such as flash memory, hard disk drive (HDD) or solid-state drive (SSD); the memory 74 may also include a combination of the above types of memory.

[0131] The processor 71 can be a central processing unit (CPU), a network processor (NP), or a combination of CPU and NP.

[0132] The processor 71 may further include a hardware chip. This hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0133] Optionally, the memory 74 is also used to store program instructions. The processor 71 can call the program instructions to implement the dynamic current-carrying capacity determination method for cooling and capacity-enhancing overhead conductors as described in this invention.

[0134] Those skilled in the art should understand that the present invention can be implemented in many other specific forms without departing from the spirit and scope of the invention. Any changes or modifications made by those skilled in the art based on the embodiments of the present invention and the above disclosure shall fall within the protection scope of the claims.

Claims

1. A method for determining the dynamic current carrying capacity of a cooling and capacity-enhancing overhead conductor, wherein the cooling and capacity-enhancing overhead conductor adopts a three-layer composite structure, the outer layer being a passive cooling coating with a thickness of 50-200 μm, the surface having a micro-nano structure to enhance mid-infrared radiation, an emissivity ≥0.92, and undergoing hydrophobic modification treatment to achieve a contact angle >120°; the middle layer being a high-conductivity aluminum alloy conductor layer, and the inner layer being a high-strength galvanized steel core; a directional heat conduction path is formed between the coating and the conductor layer through a gradient thermally conductive material, the thermal conductivity of which increases from the coating to the conductor layer; the coating is applied by axial segmented coating or mesh coating; characterized in that... Includes the following steps: S100. Perform geometric modeling of overhead conductors; S200, Correction of the heat conduction model: Calculation of equivalent emissivity for non-uniform coating: ； in, For equivalent emissivity, The emissivity of the coating is set to 0.

92. The emissivity of the bare conductor is 0.

3. Calculation of equivalent convective heat transfer coefficient: ； in, The equivalent convective heat transfer coefficient, This is the convection correction factor for the coating surface. , This is the standard convection coefficient for bare conductors. v represents wind speed; S300, Correction of the heat conduction equation: The three-dimensional non-uniform heat conduction equation is as follows: ； Where k(x, y, z) is the spatially distributed thermal conductivity, which is the thermal conductivity of the coating in the coated area and the thermal conductivity of the bare wire in the uncoated area. The mass density of the object, Let T be the specific heat capacity of the object, and T be the temperature. The rate of Joule heat generation per unit volume; S400, Constructing the finite element model: Import the 3D CAD model of the conductor; Creating coating geometry: For axial segmented coating, use periodic Boolean operations to cut the surface; for mesh coating, generate the mesh by cutting with intersecting lines. Assign material properties to the coating area; Define boundary conditions; S600, Dynamic Load Capacity Optimization: The maximum current that a conductor can withstand is determined using the equivalent heat dissipation area method, and the calculation formula is as follows: ； in, This represents the maximum current a conductor can withstand under conditions of uneven current distribution. This refers to the current that a conductor can withstand when the current is uniformly distributed. This represents the actual effective heat dissipation area. , The area of ​​the coating. Let be the area of ​​the bare conductor. This is the reference heat dissipation area under uniform heat dissipation conditions; The dynamic carrying capacity is determined based on an iterative algorithm, including the following steps: S610, Input environmental parameters include ambient temperature T air Wind speed v, heat dissipation area S of overhead conductor, and coating parameters including coating cycle number n and convective heat transfer coefficient h between overhead conductor and air; S620. Calculate the Joule heat under the current I. R is the resistance; S630. Solve the non-uniform heat conduction equation to obtain the highest temperature. ; S640, Comparison With limiting temperature T limit The size of T, if T max >T limit Calculate the new current by proportionally reducing the current. ; S650, change the current. Replace the current I and return to step S620, iterating in a loop until... Output new current As dynamic load capacity.

2. The method for determining the dynamic current carrying capacity of a cooling and capacity-enhancing overhead conductor according to claim 1, characterized in that, The axial segmented coating method is as follows: periodic coating units are set along the axial direction of the conductor. Each cycle includes a 20cm long coated area and a 10cm long uncoated area. The coated area is fully covered circumferentially, and the uncoated area exposes the conductor layer circumferentially. The coating cycle repeats to cover the entire length of the conductor.

3. The method for determining the dynamic current carrying capacity of a cooling and capacity-enhancing overhead conductor according to claim 1, characterized in that, The mesh coating method is as follows: a square mesh with a side length of 5mm is formed on the surface of the conductor, the mesh line width is 1mm, the coating thickness at the mesh intersection is 1.2-1.5 times the thickness of the edge area, and the area of ​​the uncoated area accounts for 76%.

4. The method for determining the dynamic current carrying capacity of a cooling and capacity-enhancing overhead conductor according to claim 1, characterized in that, A flexible transition layer is provided at the interface between the coating and the conductor layer, and its elastic modulus is 20%-30% of that of the coating material.

5. The method for determining the dynamic current carrying capacity of a cooling and capacity-enhancing overhead conductor according to claim 4, characterized in that, The intersections of the mesh coating are rounded with a radius ≥ 0.2 mm.

6. The method for determining the dynamic current carrying capacity of a cooling and capacity-enhancing overhead conductor according to claim 1, characterized in that, For axially segmented coated overhead conductors, the geometric definition is as follows: along the conductor's axis, the surface is divided into periodic units, with each period lasting 30 cm. Within each period, the coated area is 20 cm long, and the uncoated area is 10 cm long, with uniform full coating in the circumferential direction. This is parametrically represented as: coating coverage. Coating thickness ; For a mesh-coated overhead conductor with partial mesh coverage, the geometric definition is: a square mesh with a surface coating side length L = 5 mm and a line width w = 1 mm; parametrically represented as: coating coverage. Coating thickness .

7. The method for determining the dynamic current carrying capacity of a cooling and capacity-enhancing overhead conductor according to claim 1, characterized in that, The method also includes the following steps: S700, Thermal Stress Calculation and Analysis: Modeling of local thermal expansion differences; Temperature field input: Import the temperature distribution T(x, y, z) calculated by the heat conduction model into the structural mechanics module; The formula for calculating thermal strain is as follows: ； in, For thermal strain, The coefficient of thermal expansion is linear, and the value is taken for the coating. For bare conductor values , For reference temperature; The formula for calculating the stress concentration factor is as follows: ； in, The stress concentration factor is... The size of the coating edge defect. The radius of curvature; Finite element stress simulation: The contact is set to a non-slip bonded contact between the coating and the conductor interface, and the mesh is refined at the coating edge and mesh intersection, with a minimum element size of 0.1 mm.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the method for determining the dynamic current carrying capacity of a cooling and capacity-enhancing overhead conductor as described in any one of claims 1, 6, and 7.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the method for determining the dynamic current carrying capacity of the cooling and capacity-enhancing overhead conductor as described in any one of claims 1, 6, and 7.

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