Power transmission conductor based on tough composite carbon fiber core and preparation method thereof

Abstract

The invention relates to the technical field of smart power grids, and provides a tough composite carbon fiber core-based power transmission conductor and a preparation method thereof, and the method comprises the steps: assembling an SMA silk screen layer, a plurality of sensing optical fibers and a carbon fiber bundle into an integrated bundle body through bundling, coating the integrated bundle body through vacuum impregnation, and carrying out the curing molding of the impregnated and coated integrated bundle body, thereby obtaining the tough composite carbon fiber core-based power transmission conductor. And grating inscribing and secondary packaging are carried out on the optical fibers in the integrated beam body in the curing molding process. According to the transmission conductor based on the tough composite carbon fiber core and the preparation method of the transmission conductor, the inherent brittle fracture behavior of a traditional carbon fiber composite core can be effectively improved, the transmission conductor has excellent toughness and damage tolerance when bearing complex external force, has excellent thermal stability, long-term reliability and low linear expansion coefficient, and can realize damage early warning; a precious intervention time window is provided for operation and maintenance personnel, and the conversion from passive fault handling to active risk early warning is realized.

Description

Technical Field

[0001] This invention relates to the field of smart grid technology, and in particular to a power transmission conductor based on a tough composite carbon fiber core and its preparation method. Background Technology

[0002] High-voltage and ultra-high-voltage (UHV) power transmission networks, as core infrastructure of the national energy strategy, are crucial for achieving long-distance, high-capacity, and low-loss power transmission. In this system, overhead conductors are the physical entities carrying electrical energy, and their performance directly affects the safety, efficiency, and reliability of the entire power grid. Traditional conductors typically use a high-strength steel core as the load-bearing component, with an outer stranded aluminum or aluminum alloy conductor. In practical applications, the steel core itself is heavy, significantly increasing the overall weight and sag of the conductor, limiting transmission capacity and tower span. Under the combined effects of moisture and electrolytes, galvanic cells form between the steel (iron) and aluminum, leading to severe electrochemical corrosion, greatly shortening the conductor's lifespan and creating a risk of wire breakage.

[0003] To overcome the drawbacks of steel cores, carbon fiber reinforced composite cores have emerged. These composite cores, with their excellent specific strength, specific modulus, low coefficient of thermal expansion, and superior corrosion resistance, are considered ideal reinforcements for next-generation overhead conductors. Conductors using carbon fiber composite cores can significantly reduce line sag, increase transmission capacity, and fundamentally eliminate intermetallic corrosion. However, existing carbon fiber composite cores primarily rely on a single carbon fiber / resin matrix formed through a pultrusion process, exhibiting typical brittle fracture characteristics. This material shows almost no significant plastic deformation before failure, and cracks propagate rapidly without warning, making it impossible for line maintenance personnel to predict impending fracture like they would with metal yielding. This sudden, unpredictable failure mode poses a serious threat to power grid safety, greatly limiting the large-scale application of carbon fiber composite cores on critical transmission lines.

[0004] Current carbon fiber composite core-based conductors still rely on external sensors or inspection systems for condition monitoring, such as line inspection robots, drones, or distributed fiber optic temperature measurement systems. These methods are all "external sensing" and cannot directly and in real-time monitor the stress and strain state inside the core load-bearing component, the composite core, as well as the initiation and development of microscopic damage. This lack of sensing capability prevents line maintenance from transitioning from "planned maintenance" and "post-fault repair" to "predictive maintenance" based on real-time conditions.

[0005] Chinese patent CN104183327A discloses a self-temperature-sensing fiber optic composite conductor. Its core technology lies in "externally attached" temperature measurement: a "stainless steel optical unit" containing a fiber grating (FBG) is housed as an independent component within an annular gap between a carbon fiber composite core and an external aluminum alloy profile. In practical applications, the following shortcomings exist: 1. It can only monitor the overall ambient or average temperature of the conductor, and cannot directly and accurately sense the stress / strain state inside the carbon fiber composite core. 2. The sensing unit (stainless steel optical unit) and the load-bearing unit (carbon fiber composite core) are physically separate. During long-term operation, vibration, and creep of the conductor, the optical unit may be squeezed, worn, or subjected to micro-friction with the aluminum wire within the gap, posing a risk of damage. This loose assembly relationship makes it impossible for the sensor to accurately transmit the micro-deformation of the composite core, resulting in mechanical sensing distortion or failure. 3. It lacks the ability to monitor and warn of mechanical damage to the conductor (such as overload, strain concentration, and internal crack initiation), and cannot solve the core safety problem of the potential brittle fracture of the carbon fiber composite core without warning.

[0006] Therefore, finding an innovative composite core that can inherit the advantages of carbon fiber composites such as lightweight, high strength, and corrosion resistance, while overcoming their risk of brittle fracture and possessing inherent real-time status sensing capabilities, is of paramount importance for building safe, efficient, and intelligent next-generation transmission lines and promoting the construction of smart grids. Summary of the Invention

[0007] In view of this, in order to overcome the shortcomings of the prior art, the present invention aims to provide a power transmission conductor based on a tough composite carbon fiber core and a method for preparing the same.

[0008] According to one aspect of the present invention, a method for preparing a power transmission conductor based on a tough composite carbon fiber core is provided. The method includes: assembling an SMA wire mesh layer, multiple sensing optical fibers and a carbon fiber bundle into an integrated bundle by bundling; covering the integrated bundle by vacuum impregnation; curing the impregnated integrated bundle; performing grating writing and secondary encapsulation on the optical fibers in the integrated bundle during the curing process to obtain a tough composite carbon fiber core; and setting a conductor on the outside of the tough composite carbon fiber core.

[0009] As an optional example, the present invention is based on a method for preparing a power transmission conductor with a tough composite carbon fiber core. The integrated bundle includes, from the inside out, a carbon fiber bundle, an SMA mesh layer covering the outside of the carbon fiber bundle, and a sensing optical fiber uniformly arranged circumferentially on the outside of the SMA mesh layer.

[0010] As an optional example, the present invention is based on a method for preparing a power transmission conductor with a tough composite carbon fiber core. The carbon fiber bundle is used as the braiding and covering center. The superelastic nickel-titanium shape memory alloy wire with a diameter of 0.05-0.1 mm is braided into a mesh sleeve with a mesh density of 40-80 meshes. A nickel plating layer of 1-3 micrometers is formed on the surface of the mesh sleeve by chemical plating. The mesh sleeve with the nickel plating layer is used as the SMA wire mesh layer on the outside of the carbon fiber bundle.

[0011] As an optional example, the present invention is based on a method for preparing a power transmission conductor with a tough composite carbon fiber core, which uses constant tension to arrange multiple sensing optical fibers with a polyimide secondary coating layer at equal intervals in the circumferential direction on the outside of the SMA wire mesh layer.

[0012] As an optional example, the present invention is based on a method for preparing a power transmission conductor with a tough composite carbon fiber core. An impregnation resin with a viscosity of 800-1200 mPa·s at 25°C is prepared by using an epoxy resin blend and nano-silicon carbide particles, and the integrated bundle is impregnated and coated in a vacuum environment.

[0013] As an optional example, the present invention is based on a method for preparing a transmission conductor with a tough composite carbon fiber core. The impregnation resin is prepared as follows: 100 parts by weight of bisphenol A type epoxy resin and 8.2 parts by weight of nano-silicon carbide particles with an average particle size of 50 nm are mixed at 50°C. After cooling the mixture to 25°C, 85 parts by weight of methyltetrahydrophthalic anhydride and 0.5 parts by weight of 2-ethyl-4-methylimidazolium are added sequentially and mixed evenly. The mixture is then degassed for 30 min under a vacuum of -0.09 MPa.

[0014] As an optional example, the present invention is based on a method for preparing a power transmission conductor with a tough composite carbon fiber core, wherein the integrated bundle after impregnation and coating is processed by a pultrusion molding die, which is provided with a preheating zone of 95°C, a gelation zone of 135°C and a curing zone of 170°C.

[0015] As an optional example, the present invention is based on a method for preparing a power transmission conductor with a tough composite carbon fiber core. When the impregnated and coated integrated bundle passes through the end of the gel region of the pultrusion mold, a femtosecond laser pulse is used to etch a fiber Bragg grating on the core of the sensing fiber through a semi-transparent gel resin layer.

[0016] As an optional example, the present invention is based on a method for preparing a power transmission conductor with a tough composite carbon fiber core. After the grating is written, the grating area is locally reinforced by secondary resin encapsulation through micro-injection molding.

[0017] According to another aspect of the present invention, a power transmission conductor based on a tough composite carbon fiber core is provided, which is manufactured according to the method described above for use in smart grids.

[0018] The present invention relates to a power transmission conductor based on a tough composite carbon fiber core and its preparation method, which has the following beneficial technical effects: 1. By introducing shape memory alloy wire mesh as a toughness buffer and early warning layer, the inherent brittle fracture behavior of traditional carbon fiber composite core is effectively improved, and it has excellent toughness and damage tolerance when subjected to complex external forces.

[0019] 2. It has excellent thermal stability, long-term reliability and low coefficient of linear expansion, and can maintain dimensional and performance stability under the high temperature conditions faced by high-voltage transmission lines during long-term operation, with a significantly extended service life.

[0020] 3. It can achieve damage early warning. When the load increases to approximately 65% ​​of the rated tensile strength, the FBG can monitor the nonlinear strain response caused by the hyperelastic deformation of the SMA wire mesh and issue a reversible "Level 1 warning". When the load further increases to approximately 88% and causes microscopic damage, the FBG can capture approximately 50µε of residual strain and issue an irreversible "Level 2 warning". This provides maintenance personnel with a valuable intervention window, realizing the transformation from "passively responding to faults" to "proactively warning of risks". Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 An example diagram of the structure of the integrated beam prepared by the method of exemplary embodiment 2 of the present invention; Figure 2 A structural example diagram of a tough composite carbon fiber core prepared by the method of exemplary embodiment 2 of the present invention; In the figure, 1-integrated bundle, 2-impregnated resin body, 11-carbon fiber bundle, 12-SMA mesh layer, 13-sensing optical fiber. Detailed Implementation

[0023] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] It should be noted that, in the absence of conflict, the following embodiments and features can be combined with each other; and, based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0025] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0026] Example 1 Exemplary Example 1 of the present invention provides a method for preparing a power transmission conductor based on a tough composite carbon fiber core. The method of this embodiment is implemented as follows: an SMA (Shape Memory Alloy) wire mesh layer, multiple sensing optical fibers and carbon fiber bundles are assembled into an integrated bundle by bundling; the integrated bundle is coated by vacuum impregnation; the coated integrated bundle is cured and shaped; during the curing and shaping process, the optical fibers in the integrated bundle are grating-written and secondary-encapsulated to obtain a tough composite carbon fiber core; and a conductor is placed on the outside of the tough composite carbon fiber core.

[0027] Example 2 An exemplary embodiment of the present invention provides a method for preparing a power transmission conductor based on a tough composite carbon fiber core. The method of this embodiment is implemented in the following manner: I. Preparation of Integrated Beam Using carbon fiber bundles as the weaving and covering center, superelastic nickel-titanium shape memory alloy wires with a diameter of 0.05-0.1mm are woven into a mesh sleeve with a mesh density of 40-80 meshes. A nickel plating layer of 1-3μm is formed on the surface of the mesh sleeve by chemical plating. The mesh sleeve with the nickel plating layer is used as the SMA wire mesh layer on the outside of the carbon fiber bundle.

[0028] Multiple sensing optical fibers with a secondary polyimide coating are arranged at equal intervals in the circumferential direction on the outside of the SMA mesh layer using constant tension. Figure 1 An example diagram of the structure of the integrated beam prepared by the method of exemplary embodiment 2 of the present invention is shown below. Figure 1 As shown, in this embodiment, the integrated bundle 1 includes, from the inside out, a carbon fiber bundle 11, an SMA mesh layer 12 covering the outside of the carbon fiber bundle 11, and sensing optical fibers 13 uniformly arranged circumferentially on the outside of the SMA mesh layer 12.

[0029] II. Impregnation and Coating An impregnation resin with a viscosity of 800-1200 mPa·s at 25°C was prepared by using an epoxy resin blend and nano-silicon carbide particles. This resin was then used to impregnate and coat an integrated bundle in a vacuum environment. Specifically, in this embodiment, 100 parts by weight of bisphenol A type epoxy resin and 8.2 parts by weight of nano-silicon carbide particles with an average particle size of 50 nm were mixed at 50°C. After cooling the mixture to 25°C, 85 parts by weight of methyltetrahydrophthalic anhydride and 0.5 parts by weight of 2-ethyl-4-methylimidazolium were added sequentially and mixed thoroughly. The mixture was then degassed under a vacuum of -0.09 MPa for 30 min to obtain the impregnation resin.

[0030] Step 3: Curing, grating writing, and secondary encapsulation The impregnated and coated integrated bundle is passed through a pultrusion mold, which is equipped with a preheating zone of 95°C, a gelation zone of 135°C, and a curing zone of 170°C.

[0031] When the impregnated integrated bundle passes through the end of the gel region of the pultrusion mold, a femtosecond laser pulse is used to etch a fiber Bragg grating onto the core of the sensing fiber through a translucent gel-state resin layer. After the grating is etched, the grating area is locally reinforced with secondary resin encapsulation through micro-injection molding. Figure 2 An example structural diagram of a tough composite carbon fiber core prepared by the method of Exemplary Embodiment 2 of the present invention is shown below. Figure 2 As shown, the tough composite carbon fiber core prepared in Embodiment 2 of the present invention consists of an integrated bundle 1 and an impregnated resin body 2. The integrated bundle 1 includes, from the inside out, a carbon fiber bundle 11, an SMA mesh layer 12 covering the outside of the carbon fiber bundle 11, and a sensing optical fiber 13 uniformly arranged circumferentially on the outside of the SMA mesh layer 12. The impregnated resin body 2 covers the entire outer side of the integrated bundle 1.

[0032] Example 3 An exemplary embodiment of the present invention provides a method for preparing a power transmission conductor based on a tough composite carbon fiber core. In this embodiment, the tough composite carbon fiber core is prepared in the following manner: Step 1: Preparation of the integrated beam The carbon fiber bundles were made of polyacrylonitrile-based carbon fiber of Toray Industries, Japan, specification T700S-24K, with a single filament tensile strength of 4900 MPa and a tensile modulus of 230 GPa. The yarn spools containing the carbon fiber bundles were placed in a DHG-9070A forced-air drying oven and dried at 65°C for 2 hours.

[0033] A nickel-titanium shape memory alloy wire with a diameter of 0.08 mm (atomic ratio Ni:Ti = 50.8 at%: 49.2 at%) is used, with an austenitic phase transformation end temperature Af less than 0℃, ensuring it remains in a superelastic state at room temperature. Using an XG-36 high-speed braiding machine, the alloy wire is braided with a carbon fiber bundle as the centerline and a braiding angle of 45°±2° into a mesh sleeve with an inner diameter of 5.5 mm and a mesh density of 60 meshes.

[0034] The mesh sleeve tightly wrapped around the outside of the carbon fiber bundle is immersed in a chemical nickel plating solution with a pH of 8.5 and nickel plating is carried out at a temperature of 85°C for 25 minutes. The chemical nickel plating solution includes 30 g / L nickel sulfate, 25 g / L sodium hypophosphite, and 15 g / L sodium citrate, so that a nickel plating layer of uniform thickness is formed on the surface of the mesh sleeve.

[0035] Using a constant tension laying device, four FIBRA-PI-150 type sensing fibers (standard single-mode fibers with polyimide secondary coating, outer diameter 150μm) are laid out 90° circumferentially symmetrically on the outside of a nickel-plated mesh sleeve with a constant tension of 2N, forming an integrated bundle consisting of a T700S-24K carbon fiber bundle, a nickel-plated SMA mesh layer, and four circumferentially symmetrical sensing fibers from the inside out.

[0036] Step 2: Impregnation and Coating 100 parts by weight of bisphenol A type epoxy resin (epoxy value 0.51) and 8.2 parts by weight of nano-silicon carbide particles with an average particle size of 50 nm were accurately weighed and placed in a MIXACO FM-300 dual planetary mixer. The mixture was mixed at 50°C and 40 rpm for 40 min. The mixture was then cooled to 25°C, and 85 parts by weight of methyltetrahydrophthalic anhydride (mixed at 30 rpm for 20 min) and 0.5 parts by weight of 2-ethyl-4-methylimidazolium (mixed at 20 rpm for 10 min) were added sequentially. After mixing, the resin was transferred to a vacuum degassing tank and degassed under a vacuum of -0.095 MPa for 30 min. The viscosity of the degassed resin at 25°C was measured to be 1050 mPa·s using a Brookfield DV2T viscometer, meeting the impregnation requirements.

[0037] The impregnation process is carried out in a stainless steel vacuum pressure tank. The integrated bundle is passed through the tank at a speed of 0.8 m / min. The tank maintains a vacuum environment of -0.098 MPa. The impregnation resin is forcibly injected under a nitrogen pressure of 0.4 MPa. This synergistic mechanism of "negative pressure suction and positive pressure injection" achieves zero-defect impregnation of the integrated bundle by the impregnation resin.

[0038] Step 3: Curing, grating writing, and secondary encapsulation The coated integrated bundle is pulled forward at a constant speed of 0.8 m / min and a stable tension of 2000 N ± 50 N using a servo-driven tracked traction machine. The impregnated and coated integrated bundle enters the JWL-500 servo-controlled pultrusion production line, which is equipped with a three-stage heating mold. The temperature of each zone is precisely set as follows: preheating zone 95℃ ± 2℃, gelation zone 135℃ ± 2℃, and curing zone 170℃ ± 2℃.

[0039] When the integrated bundle after impregnation and coating reaches the end of the mold's gel region, and the impregnating resin is in a semi-cured state, a LightFab femtoscribe 100 femtosecond laser processing system integrated on the outside of the mold is used to simultaneously etch fiber Bragg gratings onto the cores of the four sensing fibers through a semi-transparent resin layer at a pulse energy of 0.5 mJ and a repetition frequency of 1 kHz. The grating period is 530.5 nm, and the grating length is 10 mm. After etching, a VERMES MDS3000 micro-dispensing system is used at the mold exit to perform local secondary encapsulation of the grating area at an injection pressure of 0.2 MPa, injecting fast-curing epoxy resin for protection.

[0040] Example 4 The tough composite carbon fiber core prepared in Example 3 of this invention was tested according to GB / T 29324-2024 "Carbon fiber reinforced composite core for overhead conductors". The test items and test results are shown in Table 1.

[0041] Table 1

[0042] As shown in Table 1, the tough composite carbon fiber core prepared in Example 3 of this invention has a tensile strength of 2750 MPa and an elastic modulus of 138 GPa, exceeding the requirements for Grade 3 strength composite cores (≥2600 MPa) in GB / T 29324-2024. By introducing shape memory alloy mesh as a toughness buffer and early warning layer, this tough composite carbon fiber core effectively improves the inherent brittle fracture behavior of traditional carbon fiber composite cores. In mechanical property tests such as winding and radial compressive strength tests, no cracking or fracture occurred, and the tensile strength retention rates after testing reached 97.4% and 96.9%, respectively, indicating that its structure has excellent toughness and damage tolerance when subjected to complex external forces.

[0043] The tough composite carbon fiber core prepared in Example 3 of this invention exhibits excellent thermal stability and long-term reliability. As shown in Table 1, its glass transition temperature reaches 266℃, which is higher than the 210℃ requirement for Class C temperature level in GB / T 29324-2024. The tensile strength retention rates after long-term heat resistance testing and thermal aging testing reached 96.2% and 92.3%, respectively, and 1.8 × 10⁻⁶. -6The low coefficient of linear expansion of / ℃ indicates that the tough composite carbon fiber core can maintain dimensional and performance stability under the high-temperature conditions faced by high-voltage transmission lines during long-term operation, and its service life is expected to be significantly extended.

[0044] Example 5 In a constant temperature laboratory environment of 23℃±0.5℃, the basic performance of the FBG sensor network, strain sensing calibration, and damage warning function detection simulation of the tough composite carbon fiber core prepared in Example 3 of this invention were carried out using an Instron 5967 universal testing machine and a MOIsm125 FBG demodulator.

[0045] For the basic performance and strain sensing calibration testing of the FBG sensor network, during sample preparation, an 800mm long sample was cut from the tough composite carbon fiber core prepared in Example 3. Both ends were made by injecting high-strength epoxy resin adhesive into the clamps, and an effective gauge length of 500mm was set. During testing, the sample was subjected to graded loading and unloading at a rate of 1mm / min. The load levels were: 0 kN (initial) → 10kN → 20kN → 30kN → 40kN → unloaded to 0kN. After each load level was stabilized for 30s, the center wavelengths of all 20 FBGs (4 fibers × 5 fibers) were recorded using an SM125 demodulator. Simultaneously, the load F applied by the testing machine and the displacement ΔL measured by the grating ruler were recorded, and the theoretical macroscopic strain εmacro = ΔL / L0 was calculated.

[0046] The test results show that all 20 FBG sensors responded at the start of the test, with a survival rate of 100%. Analysis of the data from each effective FBG, using wavelength drift Δλ as the ordinate and theoretical macroscopic strain εmacro as the abscissa, revealed a linear fit. All sensors exhibited excellent linearity, with an average strain sensitivity coefficient Kε of 1.20 pm / µε. Throughout the loading and unloading cycle, the strain value calculated from the FBG wavelength was compared with the result from the testing machine's grating ruler, with an error within ±1.5µε. The fiber optic grating sensor network integrated within the tough composite carbon fiber core achieved a 100% survival rate and a strain measurement accuracy of ±1.5µε, realizing precise and distributed monitoring of the mechanical state of the core load-bearing components.

[0047] For the damage warning function detection simulation, a 500mm long sample was cut from the tough composite carbon fiber core prepared in Example 3. A small local stress concentration point was preset in the middle of the sample. Tensile load was slowly applied on the testing machine, and the wavelength of the FBG near the preset damage point was monitored in real time. It was checked whether a nonlinear strain response caused by the hyperelastic deformation of the SMA mesh appeared when the load reached 60% RTS. After loading was continued to 85% RTS and then unloaded, it was checked whether residual strain was left on the FBG.

[0048] When the load increased to approximately 65% ​​RTS, a distinct nonlinear inflection point appeared in the monitored FBG strain-load curve, coinciding with the phase transformation initiation point of the SMA. After unloading, this nonlinear response disappeared, and the wavelength returned to its initial value. When the load was increased to 88% RTS and then unloaded, the center wavelength of the FBG in the damaged region underwent a permanent drift of approximately 60 μm, corresponding to a residual strain of approximately 50 µε, indicating that irreversible microscopic damage had occurred in the material or plastic deformation of the SMA.

[0049] The tough composite carbon fiber core of this invention can achieve damage early warning. When the load increases to about 65% of the rated tensile strength, the FBG can monitor the nonlinear strain response caused by the hyperelastic deformation of the SMA mesh and issue a reversible "Level 1 warning". When the load further increases to about 88% and causes microscopic damage, the FBG can capture about 50µε of residual strain and issue an irreversible "Level 2 warning". This provides maintenance personnel with a valuable intervention window, realizing the transformation from "passive response to faults" to "proactive risk warning".

[0050] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a power transmission conductor based on a tough composite carbon fiber core, characterized in that, The method includes: assembling an SMA wire mesh layer, multiple sensing optical fibers and carbon fiber bundles into an integrated bundle by bundling; covering the integrated bundle by vacuum impregnation; curing the impregnated integrated bundle; performing grating writing and secondary encapsulation on the optical fibers in the integrated bundle during the curing process to obtain a tough composite carbon fiber core; and setting a conductor on the outside of the tough composite carbon fiber core.

2. The method for preparing a power transmission conductor based on a tough composite carbon fiber core according to claim 1, characterized in that, The integrated bundle consists of, from the inside out, a carbon fiber bundle, an SMA mesh layer covering the outer side of the carbon fiber bundle, and sensing optical fibers uniformly arranged circumferentially on the outer side of the SMA mesh layer.

3. The method for preparing a power transmission conductor based on a tough composite carbon fiber core according to claim 1, characterized in that, Using carbon fiber bundles as the weaving and covering center, superelastic nickel-titanium shape memory alloy wires with a diameter of 0.05-0.1mm are woven into a mesh sleeve with a mesh density of 40-80 meshes. A nickel plating layer of 1-3 micrometers is formed on the surface of the mesh sleeve by chemical plating. The mesh sleeve with the nickel plating layer is used as the SMA wire mesh layer on the outside of the carbon fiber bundle.

4. The method for preparing a power transmission conductor based on a tough composite carbon fiber core according to claim 1, characterized in that, Multiple sensing optical fibers with a secondary polyimide coating are arranged at equal intervals in the circumferential direction on the outside of the SMA mesh layer using constant tension.

5. The method for preparing a power transmission conductor based on a tough composite carbon fiber core according to claim 1, characterized in that, An impregnation resin with a viscosity of 800-1200 mPa·s at 25°C was prepared by using an epoxy resin blend and nano-silicon carbide particles, and the integrated bundle was impregnated and coated in a vacuum environment.

6. The method for preparing a power transmission conductor based on a tough composite carbon fiber core according to claim 5, characterized in that, The impregnation resin was prepared as follows: 100 parts by weight of bisphenol A type epoxy resin and 8.2 parts by weight of nano-silicon carbide particles with an average particle size of 50 nm were mixed at 50 °C. After cooling the mixture to 25 °C, 85 parts by weight of methyltetrahydrophthalic anhydride and 0.5 parts by weight of 2-ethyl-4-methylimidazolium were added sequentially and mixed evenly. The mixture was then degassed for 30 min under a vacuum of -0.09 MPa.

7. The method for preparing a power transmission conductor based on a tough composite carbon fiber core according to claim 1, characterized in that, The impregnated and coated integrated bundle is passed through a pultrusion mold, which is equipped with a preheating zone of 95°C, a gelation zone of 135°C, and a curing zone of 170°C.

8. The method for preparing a power transmission conductor based on a tough composite carbon fiber core according to claim 1, characterized in that, When the impregnated integrated bundle passes through the end of the gel region of the pultrusion mold, a femtosecond laser pulse is used to etch a fiber Bragg grating on the core of the sensing fiber through the translucent gel resin layer.

9. The method for preparing a power transmission conductor based on a tough composite carbon fiber core according to claim 1, characterized in that, After the grating is written, the grating area is locally reinforced by secondary resin encapsulation through micro-injection molding.

10. A power transmission conductor based on a tough composite carbon fiber core, characterized in that, The smart grid transmission conductor based on a tough composite carbon fiber core Prepared by the method according to any one of claims 1 to 9.

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