Composite cable for new energy power generation grid connection and preparation method thereof

Abstract

The invention relates to the technical field of clean energy intelligent power grid transmission, and provides a composite cable for new energy power generation grid connection and a preparation method thereof, and the preparation method comprises the steps: preparing a composite skeleton assembly composed of an FRP composite body with a microporous structure and aramid yarn bundles embedded in the FRP composite body; the composite hydrogel is prepared through a thermal initiation polymerization method, the microporous structure of the composite framework assembly is filled with the composite hydrogel, and the power transmission unit and the communication assembly are assembled on the outer side of the composite framework assembly in a twisted mode and sequentially wrap the radial waterproof layer, the shielding layer and the outer protection layer. According to the composite cable for new energy power generation grid connection and the preparation method thereof, eddy current loss can be eliminated fundamentally, excellent axial and radial mechanical properties are obtained, meanwhile, the overall weight of the cable is remarkably reduced, an active and passive synergistic three-dimensional water blocking system is constructed, and the service life of the cable is prolonged. And the long-term water-blocking reliability of the composite cable is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of clean energy smart grid transmission technology, and in particular to a composite cable for grid connection of new energy power generation and its preparation method. Background Technology

[0002] As the global energy structure shifts towards green and low-carbon development, the scale of new energy industries such as photovoltaic and wind power generation continues to expand. Large-scale new energy power plants typically occupy vast areas, with distances between their substations and remote control centers reaching several kilometers or even tens of kilometers. In this application scenario, traditional technical solutions generally adopt a separate and independent laying model for power cables and communication optical cables, which has inherent drawbacks: First, laying power and communication lines separately requires excavating two parallel cable trenches or erecting two sets of cable tray systems, greatly occupying valuable corridor resources and leading to a significant increase in civil engineering costs, material costs, and construction time; second, separately laid cables are difficult to manage collaboratively during operation and maintenance, making fault location and troubleshooting complex and affecting the overall reliability of the system; third, for long-distance power transmission, traditional steel wire armored power cables generate considerable eddy current losses due to electromagnetic induction, reducing energy transmission efficiency.

[0003] To overcome the aforementioned problems, the industry has attempted to develop composite cables that integrate power transmission and fiber optic communication units. However, existing composite cables still have several key shortcomings in long-distance applications. In terms of mechanical performance, steel wire is still used as the central reinforcement or armor layer. While this ensures tensile strength, it results in heavy cables with poor flexibility, and the eddy current loss caused by the magnetic properties of the steel wire remains unresolved. Regarding water blocking solutions, existing technologies rely on passive water-blocking barriers composed of water-blocking powder, water-blocking yarn, and other materials. These barriers only expand after water intrusion to slow its spread, representing passive defense with limited response speed and water-blocking reliability, making it difficult to meet the stringent requirements of the internal trunk environment of the cable over its decades-long design life.

[0004] Chinese patent with publication number CN201838378U provides a smart grid distribution network and integrated cable for household access. However, this solution has the following shortcomings in practical applications: it relies on the filling of gaps by "water-blocking cable paste" and the radial blocking by "water-blocking sheath". Once the sheath is damaged or the cable paste dries up and migrates during long-term operation, its water-blocking efficiency will decrease significantly.

[0005] Therefore, how to provide a new type of load-bearing structure to replace steel wire armor, fundamentally eliminate eddy current loss and reduce weight, and achieve a more proactive, intelligent and reliable water-blocking mechanism to ensure permanent dryness inside long-distance cables, while meeting comprehensive performance requirements such as lightweight, high strength, full-section water blocking, high electromagnetic compatibility and long life, has become an urgent technical problem to be solved. Summary of the Invention

[0006] In view of this, in order to overcome the shortcomings of the prior art, the present invention aims to provide a composite cable for grid connection of new energy power generation and its preparation method.

[0007] According to one aspect of the present invention, a method for preparing composite cables for grid connection of new energy power generation is provided. The method includes: preparing a composite skeleton assembly composed of an FRP composite with a microporous structure and aramid yarn bundles embedded in the FRP composite; preparing a composite hydrogel by thermally initiated polymerization; filling the microporous structure of the composite skeleton assembly with the composite hydrogel; and twisting and assembling a power transmission unit and a communication component on the outside of the composite skeleton assembly and sequentially covering them with a radial water-blocking layer, a shielding layer and an outer sheath.

[0008] Optionally, in the method for preparing composite cables for grid connection of new energy power generation of the present invention, the composite skeleton component is composed of an FRP composite with micropores and multiple aramid yarn bundles embedded in the FRP composite. The FRP composite, which is in the shape of a hollow cylinder, is composed of multiple basalt fiber untwisted rovings and a resin body covering the outside of the basalt fiber untwisted rovings. The aramid yarn bundles are uniformly embedded in the resin body of the FRP composite.

[0009] Optionally, the method for preparing composite cables for grid connection of new energy power generation of the present invention uses an epoxy vinyl ester resin material system to impregnate guided basalt fiber untwisted roving, and forms the impregnated fiber bundle into an extruded composite with a microporous structure by pultrusion and vapor phase pore forming method, thermally embeds aramid yarn bundle into the viscous flow resin of the extruded composite, and obtains the composite skeleton component by step curing.

[0010] Optionally, in the method for manufacturing composite cables for grid connection of new energy power generation of the present invention, the composite skeleton assembly is prepared in the following manner: Basalt fiber rovings with a linear density of 1200Tex were guided and immersed in an epoxy vinyl ester resin material system at 28℃ and 450 mPa·s to form impregnated fiber bundles with a colloidal volume of 8%. The resin-impregnated fiber bundles are extruded through a die at 110°C. During the extrusion process, high-purity nitrogen gas at a pressure of 0.25 MPa is used to form an FRP composite with a microporous structure inside the resin. The aramid yarn bundles are guided into the viscous resin embedded in the FRP composite at the extrusion die outlet. The extruded composite with embedded aramid yarn bundles is then subjected to step curing at 120℃×20s, 150℃×90s and 135℃×50s, followed by natural cooling.

[0011] Optionally, in the method for preparing composite cables for grid connection of new energy power generation of the present invention, the epoxy vinyl ester resin material system is prepared by premixing epoxy vinyl ester resin liquid, methyl ethyl ketone peroxide and cobalt naphthenate in a weight ratio of 100:1.2:0.5, and then stirring at 350 rpm for 25 min at 40°C.

[0012] Optionally, in the method for preparing composite cables for grid connection of new energy power generation of the present invention, before embedding the aramid yarn bundle into the FRP composite, an atmospheric pressure plasma with a power of 800W is used to perform plasma treatment on the aramid yarn bundle at a treatment distance of 2mm. The aramid yarn passes through the plasma treatment area at a speed of 10m / min, and the plasma-treated aramid yarn bundle is heated to 70°C.

[0013] Optionally, the method for preparing composite cables for grid-connected new energy power generation of the present invention involves adding 15 parts by weight of a sodium acrylate solution with a pH of 7.0±0.2 and a mass fraction of 30wt%, 1.5 parts by weight of a colloidal nanocellulose dispersion with a mass fraction of 1.8wt%, 0.07 parts by weight of N,N'-methylenebisacrylamide, and 0.4 parts by weight of potassium persulfate to 82 parts by weight of deionized water. The mixture is stirred at 450 rpm for 25 min at 55°C, and nitrogen gas is introduced into the reaction system at a rate of 0.5 L / min for 20 min. The reaction system is then heated to 65°C in a nitrogen atmosphere and reacted at a constant temperature for 3 h to obtain a composite hydrogel.

[0014] Optionally, in the method for preparing composite cables for grid connection of new energy power generation of the present invention, a composite hydrogel with a solid content of not less than 65% and a water absorption expansion rate of not less than 550% is injected into the microporous structure of the composite skeleton component at a constant flow rate of 2.5 mL / min, and the injection filling amount is 80% of the volume of the microporous structure.

[0015] Optionally, in the method for preparing composite cables for grid connection of new energy power generation of the present invention, the radial water-blocking layer is made by wrapping water-absorbing fiber non-woven tape with an overlapping wrapping at a 45° helix angle and a 25% overlap rate, and the shielding layer is made by wrapping a composite metal tape with a three-layer structure of aluminum foil / polyethylene terephthalate film / copper foil with an overlapping wrapping at a 30° helix angle and a 30% overlap rate. The spiral wrapping direction of the shielding layer is opposite to that of the radial water-blocking layer.

[0016] According to another aspect of the present invention, a composite cable for grid connection of new energy power generation is provided, which is manufactured according to the above-described method.

[0017] The composite cable for grid connection of new energy power generation and its preparation method of the present invention have the following beneficial technical effects: 1. A microporous FRP (fiber-reinforced polymer) composite is used as the core skeleton, with embedded high-modulus aramid yarn bundles, replacing traditional metal load-bearing components. The inherent non-magnetic properties of FRP material fundamentally eliminate eddy current losses and improve power transmission efficiency. While achieving excellent axial and radial mechanical properties, the overall weight of the cable is significantly reduced due to the much lower density of the FRP composite and aramid yarn compared to steel, reducing the difficulty and cost of transportation and installation, and also facilitating laying in complex terrains (such as mountainous areas and offshore wind farms).

[0018] 2. A three-dimensional water-blocking system combining active and passive mechanisms was constructed. The microporous structure of the FRP composite was pre-filled with a composite hydrogel with a high water absorption and expansion rate. When the cable sheath is damaged and water enters, the gel can expand rapidly and actively block the water seepage channels to achieve water blocking. This active mechanism works in conjunction with the passive water-blocking barrier formed by the wrapping layer of water-absorbing non-woven fabric to ensure the long-term water-blocking reliability of the composite cable. It is especially suitable for long-distance, high-reliability power and signal transmission between the substation and the control center in large photovoltaic power plants, wind power plants and other new energy sites. Attached Figure Description

[0019] 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.

[0020] Figure 1 This is a flowchart illustrating the method for preparing composite cables for grid connection of new energy power generation according to an exemplary embodiment 1 of the present invention. Figure 2 This is a schematic diagram of the structure of the composite skeleton component prepared according to exemplary embodiment 2 of the present invention; Figure 3 This is a schematic diagram of the structure of a composite cable for grid connection of new energy power generation prepared according to exemplary embodiment 2 of the present invention; In the figure, 1-composite skeleton component, 11-FRP composite, 12-aramid yarn bundle, 111-basalt fiber untwisted roving, 112-resin body, 2-power transmission unit, 3-communication component, 4-radial water-blocking layer, 5-shielding layer, 6-outer protective layer. Detailed Implementation

[0021] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0022] 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.

[0023] 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.

[0024] Example 1 Exemplary Example 1 of the present invention provides a method for preparing composite cables for grid connection of new energy power generation. Figure 1 This is a flowchart illustrating a method for preparing composite cables for grid connection of new energy power generation according to an exemplary embodiment 1 of the present invention. Figure 1 As shown, the method of this embodiment is implemented in the following manner: Step S1: Prepare a composite skeleton assembly consisting of an FRP composite with a microporous structure and aramid yarn bundles embedded in the FRP composite.

[0025] In this embodiment, epoxy vinyl ester resin material system is used to impregnate guided basalt fiber untwisted roving. The impregnated fiber bundle is formed into an extruded composite with a microporous structure by pultrusion and vapor phase pore forming method. The aramid yarn bundle is thermally embedded into the viscous flow resin of the extruded composite and the composite skeleton component is obtained by step curing. Figure 2 This is a schematic diagram of the structure of the composite skeleton component prepared according to exemplary embodiment 2 of the present invention, as shown below. Figure 2 As shown, the composite skeleton component 1 prepared in this embodiment consists of an FRP composite 11 with micropores and multiple aramid yarn bundles 12 embedded in the FRP composite 11. The FRP composite 11, which is in the shape of a hollow cylinder, consists of multiple basalt fiber untwisted rovings 111 and a resin body 112 covering the outside of the basalt fiber untwisted rovings. The aramid yarn bundles 12 are uniformly embedded in the resin body 112 of the FRP composite 11.

[0026] Step S2: Prepare composite hydrogel by thermally initiated polymerization and fill the microporous structure of the composite framework component with the composite hydrogel.

[0027] A composite hydrogel was prepared by mixing sodium acrylate solution and colloidal nanocellulose dispersion in a nitrogen atmosphere. The prepared composite hydrogel was then injected into the microporous structure of the composite framework component at a constant flow rate.

[0028] Step S3: The power transmission unit and communication components are twisted and assembled on the outside of the composite frame assembly and then covered with a radial water-blocking layer, a shielding layer and an outer protective layer in sequence.

[0029] Figure 3 This is a schematic diagram of the structure of a composite cable for grid connection of new energy power generation prepared according to exemplary embodiment 2 of the present invention, as shown below. Figure 3 As shown, in this embodiment, multiple power transmission units 2 and communication components 3 are arranged circumferentially at intervals on the outside of the composite skeleton component 1 filled with composite hydrogel to form a cable core assembly. A radial water-blocking layer 4, a shielding layer 5, and an outer sheath 6 are sequentially arranged on the outside of the cable core assembly. As an optional example, in this embodiment, a water-absorbing fiber non-woven fabric tape is used to prepare the radial water-blocking layer 4 on the outside of the cable core assembly in a spiral overlapping wrapping manner, and a composite metal tape with a three-layer structure of aluminum foil / polyethylene terephthalate film / copper foil is used to prepare the shielding layer 5 in a spiral overlapping wrapping manner. The spiral wrapping direction of the shielding layer 5 is opposite to that of the radial water-blocking layer 4.

[0030] Example 2 Exemplary Example 2 of the present invention provides a method for preparing composite cables for grid connection of new energy power generation. In this embodiment, the composite skeleton assembly is prepared in the following manner: Basalt fiber rovings with a linear density of 1200 Tex were guided and immersed in an epoxy vinyl ester resin material system at 28°C and 450 mPa·s to form impregnated fiber bundles with a colloidal volume of 8%. In this embodiment, the epoxy vinyl ester resin material system was prepared by premixing epoxy vinyl ester resin liquid, methyl ethyl ketone peroxide, and cobalt naphthenate in a weight ratio of 100:1.2:0.5, and then stirring at 350 rpm for 25 min at 40°C.

[0031] The resin-impregnated fiber bundles are extruded through a die at 110°C. During the extrusion process, high-purity nitrogen gas at a pressure of 0.25 MPa is used to form an FRP composite with a microporous structure inside the resin.

[0032] The aramid yarn bundles are guided into the viscous resin embedded in the FRP composite at the extrusion die outlet. The extruded composite with the embedded aramid yarn bundles is then subjected to stepped curing at 120℃×20s, 150℃×90s, and 135℃×50s, followed by natural cooling. Before embedding the aramid yarn bundles into the FRP composite, the aramid yarn bundles are plasma-treated using an 800W atmospheric pressure plasma at a treatment distance of 2mm. The aramid yarn passes through the plasma treatment zone at a speed of 10m / min, and the plasma-treated aramid yarn bundles are heated to 70℃.

[0033] The micropore volume ratio of the composite skeleton component prepared in Example 2 of this invention was tested using the vacuum impregnation-density calculation method. Three regular cuboid samples with dimensions of 10mm × 10mm × 5mm were cut from the composite skeleton component. The cut surfaces were smooth and did not contain aramid yarn bundles. The samples were placed in a vacuum drying oven at 105℃ for 4 hours until constant weight was achieved. After cooling to room temperature in a desiccator, their dried mass (Md) was measured using an analytical balance with an accuracy of 0.0001g. The samples were completely immersed in anhydrous ethanol of known density (ρf) and placed in a vacuum desiccator, maintained at a vacuum of -0.095MPa for 2 hours to ensure that the impregnation solution fully filled all open pores. After releasing the vacuum, the saturated samples were suspended in the impregnation solution, and their apparent mass (Ms) was measured using the Archimedes displacement method and the same analytical balance. The micropore volume ratio Vp = [(Ms-Md) / ρf] / V0 × 100%, where V0 is the geometric volume of the sample. The measured micropore volume percentages of the three samples were 32.8%, 30.5%, and 29.5%, respectively, with an average of 30.9%. This indicates that the vapor phase pore formation process is stable and reliable, and a uniform and controllable three-dimensional microporous network was constructed within the FRP composite. This provides a precise volume basis for the subsequent quantitative and uniform filling of the composite hydrogel, which is a prerequisite for ensuring the effectiveness of the active water-blocking system.

[0034] Example 3 Exemplary Example 3 of the present invention provides a method for preparing composite cables for grid connection of new energy power generation. In this embodiment, a composite hydrogel is prepared and filled into the microporous structure of the composite skeleton component in the following manner: 15 parts by weight of a 30 wt% sodium acrylate solution with a pH of 7.0 ± 0.2, 1.5 parts by weight of a 1.8 wt% colloidal nanocellulose dispersion, 0.07 parts by weight of N,N'-methylenebisacrylamide, and 0.4 parts by weight of potassium persulfate were added to 82 parts by weight of deionized water. The mixture was stirred at 450 rpm for 25 min at 55 °C. Nitrogen gas was then introduced into the reaction system at a rate of 0.5 L / min for 20 min. The reaction system was then heated to 65 °C under a nitrogen atmosphere and reacted at this temperature for 3 h to obtain a composite hydrogel.

[0035] A composite hydrogel with a solid content of not less than 65% and a water absorption swelling rate of not less than 550% was injected into the microporous structure of the composite framework component at a constant flow rate of 2.5 mL / min, and the injection filling amount was 80% of the microporous structure volume.

[0036] Example 4 Exemplary Example 4 of the present invention provides a method for preparing a composite cable for grid connection of new energy power generation. The structural parameters of the composite cable for grid connection of new energy power generation prepared according to this embodiment are shown in Table 1 below.

[0037] Table 1

[0038] An Instron 5967 universal testing machine equipped with a hydraulic push-type clamp was used to test the axial tensile strength of the composite skeleton assembly of the new energy power generation grid-connected composite cable prepared in Example 4, as shown in Table 1. During sample preparation, a diamond cutter was used to cut a sample of 800±5 mm in length from different parts (both ends and the middle) of the finished cable prepared in the example. The outer sheath, shielding layer, and radial water-blocking layer of the clamping area at each end of the sample were cleaned. The surface of the clamping area was lightly sanded with 400-grit sandpaper to increase friction, and the surface was cleaned with anhydrous ethanol. A BE120-3AA type axial strain gauge was precisely attached to the middle section of each sample for real-time monitoring of strain changes. During testing, the clamping distance was set to 500 mm, the preload force to 50 N, the tensile speed to 10 mm / min, and complete stress-strain data were acquired at a frequency of 100 Hz.

[0039] All specimens fractured after reaching peak loads ranging from 84.5 kN to 85.2 kN, with an average tensile strength of 965 MPa. The fracture locations all occurred outside the clamping area in the middle section of the specimens, and the fracture morphology showed typical fiber tensile fracture characteristics. The basalt fibers and resin matrix were well bonded, and the aramid yarn bundles and FRP skeleton worked together to bear the load, with no obvious interfacial delamination observed.

[0040] The radial compressive strength of the composite skeleton assembly of the new energy power generation grid-connected composite cable prepared in Example 4, as shown in Table 1, was tested using an MTS C42.503 compression testing machine equipped with a 100mm diameter circular flat indenter. During sample preparation, the composite skeleton assembly was completely separated from the cable, and five standard-length specimens were precisely cut, ensuring that the parallelism error of the two end faces of the specimens was no greater than 0.05mm. Three displacement sensors were evenly arranged circumferentially in the middle of the specimens to accurately measure the radial deformation during compression. During testing, a loading speed of 5mm / min was applied, with a maximum load of 50kN.

[0041] When the load increased to 40 kN, audible microcracks began to appear on the sample, but the structure maintained its overall integrity and did not fracture brittlely. The maximum compressive strength measured was 267 MPa when the deformation reached 3.5 mm. After unloading, the sample exhibited a maximum permanent plastic deformation of 0.8 mm, but did not lose its basic structural function. These results demonstrate that the composite skeleton assembly possesses excellent compressive strength and energy absorption characteristics, effectively resisting external compression and impact, and ensuring the internal structural safety of the cable in complex laying environments.

[0042] This invention employs a microporous FRP (fiber-reinforced polymer) composite as the core framework, embedding high-modulus aramid yarn bundles to replace traditional metal load-bearing components. The inherent non-magnetic properties of FRP fundamentally eliminate eddy current losses, improving power transmission efficiency. While achieving excellent axial and radial mechanical properties, the overall weight of the cable is significantly reduced due to the much lower density of the FRP composite and aramid yarn compared to steel, lowering the difficulty and cost of transportation and installation, and facilitating laying in complex terrains (such as mountainous areas and offshore wind farms).

[0043] The water-blocking performance of the composite hydrogel in the microporous structure of the composite skeleton component of the new energy power generation grid-connected composite cable prepared in Example 4, as shown in Table 1, was tested using a longitudinal water-blocking test device. The longitudinal water-blocking test device included a pressure tank, a pressure gauge with an accuracy of 0.25%, and a sample sealing clamp. During sample preparation, a sample with a length of 3000±10 mm was cut, ensuring a flat end face. The outer sheath within 50 mm of each end was removed to expose the radial water-blocking layer, and a sealing clamp was installed. A 0.1% methylene blue staining solution was injected into one end for observation, and a precise seepage collection device was connected to the other end. The test water pressure was 0.01 MPa (equivalent to 1 m water column), the test water temperature was controlled at 20±5℃, and the holding time was 24 h.

[0044] Under continuous 24-hour testing conditions with a water pressure of 0.01 MPa, no droplets were collected in the seepage collection device at the end of the longitudinal water-blocking test system. After the test, the sealing fixture was disassembled and the sample end face and interior were dissected and inspected. It was found that the dyed water outside the radial water-blocking layer was effectively blocked, and the microporous structure inside the composite skeleton component showed a dense gel blocking layer due to the full expansion of the hydrogel, and the inside of the cable core remained dry.

[0045] The expansion performance of the composite hydrogel in the microporous structure of the composite framework component prepared in Example 4 of this invention was tested using an analytical balance with an accuracy of 0.0001 g, a constant-temperature oscillating water bath with a temperature control accuracy of ±0.5℃, and an 80-mesh standard sieve. For sample preparation, approximately 1.0 g of composite hydrogel sample was scraped from the microporous structure of the composite framework component. The sample was then dried in a 40℃ oven until constant weight (defined as a weight change of less than 0.1%). 0.5000 g of the dried sample was weighed using an analytical balance, placed in an 80-mesh nylon mesh bag, and sealed. The test liquid was deionized water with a conductivity not exceeding 10 μS / cm. The test temperature was maintained at 20±1℃, the soaking time was set to 30 min, and the oscillation frequency was 60 r / min.

[0046] After being soaked in deionized water for 30 minutes, the dried sample absorbed 3.05g of water, and its water absorption swelling rate was 610%, indicating that the composite hydrogel has high water absorption properties, and its swelling rate and final swelling ratio can meet the requirements for quickly forming an effective water barrier under actual use conditions.

[0047] This invention constructs a three-dimensional water-blocking system that combines active and passive mechanisms. The microporous structure of the FRP composite is pre-filled with a composite hydrogel with a high water absorption and expansion rate. When the cable sheath is damaged and water enters, the gel can expand rapidly and actively block the water seepage channels to achieve water blocking. This active mechanism works in conjunction with the passive water-blocking barrier formed by the wrapping layer of water-absorbing non-woven fabric to ensure the long-term water-blocking reliability of the composite cable.

[0048] 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 composite cable for grid connection of new energy power generation, characterized in that, The method includes: preparing a composite skeleton assembly consisting of an FRP composite with a microporous structure and aramid yarn bundles embedded in the FRP composite; preparing a composite hydrogel by thermally initiated polymerization; filling the microporous structure of the composite skeleton assembly with the composite hydrogel; and twisting and assembling the power transmission unit and communication component on the outside of the composite skeleton assembly and sequentially covering them with a radial water-blocking layer, a shielding layer and an outer protective layer.

2. The method for preparing composite cables for grid connection of new energy power generation according to claim 1, characterized in that, The composite skeleton component consists of a microporous FRP composite and multiple aramid yarn bundles embedded in the FRP composite. The FRP composite, which is in the shape of a hollow cylinder, consists of multiple basalt fiber untwisted rovings and a resin body covering the outside of the basalt fiber untwisted rovings. The aramid yarn bundles are uniformly embedded in the resin body of the FRP composite.

3. The method for preparing composite cables for grid connection of new energy power generation according to claim 1, characterized in that, A basalt fiber roving was impregnated with an epoxy vinyl ester resin material system. The impregnated fiber bundles were formed into an extruded composite with a microporous structure by pultrusion and vapor phase pore formation. The aramid yarn bundles were thermally embedded into the viscous resin of the extruded composite and the composite skeleton component was obtained by step curing.

4. The method for preparing composite cables for grid connection of new energy power generation according to claim 3, characterized in that, The composite framework assembly is prepared in the following manner: Basalt fiber rovings with a linear density of 1200Tex were guided and immersed in an epoxy vinyl ester resin material system at 28℃ and 450 mPa·s to form impregnated fiber bundles with a colloidal volume of 8%. The resin-impregnated fiber bundles are extruded through a die at 110°C. During the extrusion process, high-purity nitrogen gas at a pressure of 0.25 MPa is used to form an FRP composite with a microporous structure inside the resin. The aramid yarn bundles are guided into the viscous resin embedded in the FRP composite at the extrusion die outlet. The extruded composite with embedded aramid yarn bundles is then subjected to step curing at 120℃×20s, 150℃×90s and 135℃×50s, followed by natural cooling.

5. The method for preparing composite cables for grid connection of new energy power generation according to claim 4, characterized in that, The epoxy vinyl ester resin material system was prepared by premixing epoxy vinyl ester resin liquid, methyl ethyl ketone peroxide and cobalt naphthenate in a weight ratio of 100:1.2:0.5, and then stirring at 350 rpm for 25 min at 40°C.

6. The method for preparing composite cables for grid connection of new energy power generation according to claim 1, characterized in that, Before embedding the aramid yarn bundle into the FRP composite, the aramid yarn bundle is plasma-treated with an atmospheric pressure plasma of 800W at a treatment distance of 2mm. The aramid yarn passes through the plasma treatment area at a speed of 10m / min, and the plasma-treated aramid yarn bundle is heated to 70℃.

7. The method for preparing composite cables for grid connection of new energy power generation according to claim 1, characterized in that, 15 parts by weight of a 30 wt% sodium acrylate solution with a pH of 7.0 ± 0.2, 1.5 parts by weight of a 1.8 wt% colloidal nanocellulose dispersion, 0.07 parts by weight of N,N'-methylenebisacrylamide, and 0.4 parts by weight of potassium persulfate were added to 82 parts by weight of deionized water. The mixture was stirred at 450 rpm for 25 min at 55 °C. Nitrogen gas was then introduced into the reaction system at a rate of 0.5 L / min for 20 min. The reaction system was then heated to 65 °C under a nitrogen atmosphere and reacted at this temperature for 3 h to obtain a composite hydrogel.

8. The method for preparing composite cables for grid connection of new energy power generation according to claim 1, characterized in that, A composite hydrogel with a solid content of not less than 65% and a water absorption swelling rate of not less than 550% was injected into the microporous structure of the composite framework component at a constant flow rate of 2.5 mL / min, and the injection filling amount was 80% of the microporous structure volume.

9. The method for preparing composite cables for grid connection of new energy power generation according to claim 1, characterized in that, The radial water-blocking layer is made by wrapping water-absorbing fiber non-woven tape with an overlapping 45° spiral angle and a 25% overlap rate. The shielding layer is made by wrapping a composite metal tape with a three-layer structure of aluminum foil / polyethylene terephthalate film / copper foil with an overlapping 30° spiral angle and a 30% overlap rate. The spiral wrapping direction of the shielding layer is opposite to that of the radial water-blocking layer.

10. A composite cable for grid connection of new energy power generation, characterized in that, The composite cable for grid connection of new energy power generation is prepared according to any one of claims 1 to 9.

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