A grid bundled conductor suitable for oil-immersed power transformer and its single-side reinforcing process

Abstract

The application discloses a grid binding wire suitable for oil-immersed power transformers and a single-side reinforcing process thereof, and belongs to the technical field of transformer manufacturing, which comprises a wire main body, a composite wire grid wound on the outer periphery of the wire main body, and a single-side insulating reinforcing layer arranged on one side of the wire main body, the composite wire grid is formed by orthogonally laying a plurality of sub composite wires, the sub composite wires are spaced apart along the axial direction and are provided with a plurality of independently formed heat dissipation support nodes, the sub composite wire comprises a force-bearing inner core and a resin matrix wrapped on the force-bearing inner core, and an in-situ press-in interlocking structure is formed between the single-side insulating reinforcing layer and the composite wire grid, and the composite wire grid containing the independently formed heat dissipation support nodes is adopted in cooperation with the single-side insulating reinforcing layer with compressible volume, so that the contradiction between the insufficient short-circuit resistance of the winding of the large oil-immersed transformer and the local overheating is solved.

Description

Technical Field

[0001] This invention relates to the field of transformer winding insulation structure technology, and in particular to a mesh-bound conductor suitable for oil-immersed power transformers and its single-sided reinforcement process. Background Technology

[0002] In the manufacture of large oil-immersed power transformers, the mechanical stability and heat dissipation performance of the windings have always been a difficult contradiction to reconcile. On the one hand, in order to resist the huge electrodynamic force generated during a short circuit, the winding conductors must have extremely high mechanical fixing strength. On the other hand, in order to ensure the circulation and cooling of the transformer oil, the surface of the conductors cannot be completely covered by insulating material, and sufficient heat dissipation oil channels must be reserved.

[0003] Existing technical solutions typically employ adhesive bonding or prefabricated mesh for fixation. However, with the increase in transformer capacity, traditional processes have revealed significant shortcomings: existing reinforcing insulation layers usually use solid resin tape or adhesives. When the wire mesh is pressed into the insulation layer to increase fixation strength, according to the principle of volume conservation, the displaced resin inevitably flows outwards, forming irregular burrs. These burrs are prone to detaching and entering the oil tank, or directly clogging the fine cooling oil channels, leading to localized overheating or even discharge faults. Traditional mesh and insulation layers are mostly simply bonded to a flat surface, lacking deep mechanical interlocking. Under long-term thermal aging and alternating electromagnetic forces, interface debonding easily occurs, resulting in a significant decrease in shear resistance. Furthermore, to control adhesive overflow, existing processes often strictly limit the pressing depth, which in turn leads to a loose bond between the mesh and the insulation layer, failing to form an effective overall load-bearing structure. Summary of the Invention

[0004] This invention overcomes the shortcomings of the prior art and provides a mesh-bound conductor suitable for oil-immersed power transformers and its single-sided reinforcement process.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a grid-bound conductor suitable for oil-immersed power transformers, comprising: a conductor body, a composite conductor grid wrapped around the outer periphery of the conductor body, and a single-sided insulation reinforcement layer disposed on one side of the conductor body;

[0006] The composite wire mesh is formed by laying several sub-composite wires orthogonally, and the sub-composite wires are distributed with several independently formed heat dissipation support nodes at intervals along the axial direction.

[0007] The sub-composite conductor includes a load-bearing inner core and a resin matrix covering the load-bearing inner core;

[0008] An in-situ press-fit interlocking structure is formed between the single-sided insulating reinforcement layer and the composite wire mesh. The in-situ press-fit interlocking structure refers to the heat dissipation support node being at least partially embedded in the thickness direction of the single-sided insulating reinforcement layer as a rigid punch, and the heat dissipation support node and the single-sided insulating reinforcement layer having a zero-gap co-curing connection interface.

[0009] In a preferred embodiment of the present invention, the heat dissipation support node has an olive pit-shaped or microspherical structure, and the surface of the heat dissipation support node is covered with an array of pit structures.

[0010] In a preferred embodiment of the present invention, the load-bearing inner core is high-strength glass fiber, and the surface of the load-bearing inner core has mechanical anchoring points formed by micro-etching. The resin matrix is ​​a fully cured highly cross-linked modified epoxy resin, the resin matrix is ​​doped with boron nitride whiskers, and the resin matrix is ​​filled with nano-silica.

[0011] In a preferred embodiment of the present invention, the single-sided insulating reinforcement layer is a defoaming resin curing material containing micropores or composite hollow spheres, and the area where the heat dissipation support node is embedded in the single-sided insulating reinforcement layer is formed by local internal compression and accommodation of the single-sided insulating reinforcement layer.

[0012] In a preferred embodiment of the present invention, the composite wire mesh is a suspended double-layer orthogonal structure, which includes a first layer of sub-composite wires laid in parallel longitudinal direction and a second layer of sub-composite wires laid in a lateral circumferential direction. The first layer of composite wires and the second layer of composite wires are only spot-welded together at the intersection of the heat dissipation support nodes.

[0013] In a preferred embodiment of the present invention, the following steps are included:

[0014] S1: The resin matrix is ​​mixed with fillers containing microbubble structure or hollow microsphere structure to form a slurry. The slurry is then coated and baked to allow the resin matrix to undergo a preliminary cross-linking reaction, thus preparing an insulating tape in a semi-cured state.

[0015] S2: Cover one side of the conductor body that has been wrapped with composite wire mesh with the semi-cured insulation tape and apply radial pressure. Use the fully cured heat dissipation support nodes on the composite wire mesh as rigid punches to press into the insulation tape.

[0016] S3: During the pressing process, the rupture or compression of the microbubble structure or hollow microsphere structure inside the semi-cured insulation tape is used to promote the in-situ absorption of the volume displaced by the heat dissipation support node inside the semi-cured insulation tape.

[0017] S4: While maintaining radial pressure, heat the semi-cured insulation tape and heat dissipation support node to transform the semi-cured insulation tape into a fully cured state, thereby forming a single-sided insulation reinforcement layer.

[0018] In a preferred embodiment of the present invention, in step S1, the resin matrix is ​​a thermosetting epoxy resin matrix, the slurry further contains a curing agent and an accelerator, and the filler is a closed-cell hollow microsphere with a volume fraction of 20%-40%.

[0019] The baking process is controlled within a temperature range of 80℃-100℃ for five to ten minutes, so that the resin matrix undergoes a preliminary cross-linking reaction but does not form a three-dimensional network structure, and the degree of curing of the semi-cured insulation tape is controlled between 40% and 60%.

[0020] In a preferred embodiment of the present invention, in step S2, the heat dissipation support node has been pre-cured, and its hardness is greater than that of the insulating tape in the semi-cured state.

[0021] The radial pressure is set to 0.5MPa-2.0MPa. The radial pressure is greater than the yield strength of the microbubble structure in the semi-cured insulation tape and less than the destructive strength of the load-bearing core in the composite conductor grid.

[0022] In a preferred embodiment of the present invention, in step S3, the total volume of the insulating tape containing microbubble structures or hollow microsphere structures in the semi-cured state within the pressure area is greater than or equal to the volume displaced by the heat dissipation support node.

[0023] The microbubble or hollow microsphere structure in the pressure area breaks or collapses, which increases the density of the pressure area of ​​the insulation tape in the semi-cured state while keeping the overall outline size unchanged.

[0024] In a preferred embodiment of the present invention, in step S4, the heating process is to cure at a constant temperature of 130℃-150℃ for two to four hours;

[0025] The resin matrix of the insulating tape in a semi-cured state undergoes chemical bonding with the residual active groups on the surface of the heat dissipation support node to achieve co-curing. The shear resistance of the connection interface formed after complete curing is provided by the tenon structure formed by the single-sided insulating reinforcement layer embedded in the insulating tape by the heat dissipation support node.

[0026] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0027] (1) The present invention uses a composite wire mesh containing independently formed heat dissipation support nodes, combined with a single-sided insulation reinforcement layer with compressibility, to construct an in-situ press-fit interlocking structure. The fully cured high-hardness heat dissipation support nodes are used as rigid punches and forcibly pressed into the insulation strip which is in a semi-cured state and contains microbubbles or hollow microspheres, so that the two form a zero-gap co-cured connection interface, realizing the deep physical integration of the wire and the insulation layer in the thickness direction. It also solves the volume displacement problem in the pressing process through the micro-volume absorption mechanism inside the insulation layer. Compared with the situation in the prior art where mechanical fixing strength and heat dissipation performance are difficult to balance, the present invention improves the overall mechanical stability of the winding without sacrificing the smoothness of the heat dissipation oil channel, effectively solving the contradiction of insufficient short-circuit resistance and local overheating of the winding of large oil-immersed transformer.

[0028] (2) This invention designs the heat dissipation support node as an olive pit or microsphere structure and makes its surface covered with an array of pits. It uses a pre-curing process to make its hardness much higher than that of semi-cured insulation tape. Under radial pressure, it is embedded in the insulation layer to form a tenon structure, which generates a strong mechanical interlocking effect between the node and the insulation layer. This transforms the original simple interlayer chemical bonding into normal pressure and mechanical interlocking force, thereby achieving high shear resistance. Compared with the existing technology where the mesh and the insulation layer rely only on planar bonding, which is prone to interface debonding under long-term thermal aging and electromagnetic vibration, this invention improves the anchoring strength of the wire mesh, ensuring that the winding wires do not undergo relative displacement or loosening when the transformer is subjected to short-circuit electrodynamic impact, thus ensuring the safe operation of the equipment.

[0029] (3) The present invention introduces a microbubble structure or composite hollow sphere into the single-sided insulation reinforcement layer, making it a special medium with compressibility. When the rigid heat dissipation support node is pressed in, the insulation layer absorbs the displaced volume in situ through the rupture or compression and densification of the local microspheres, so that the density of the pressure area of ​​the insulation layer increases while the overall outline size remains unchanged, thus eliminating the phenomenon of resin flowing and overflowing to the surroundings from the root. Compared with the existing technology, which forcibly presses in a solid insulation layer to increase the fixing strength, resulting in the formation of irregular flash, blockage of micro heat dissipation oil channels or shedding and contamination of transformer oil, the present invention achieves zero flash pressing, which not only ensures the absolute unobstructed heat dissipation oil channels around the node, but also avoids local overheating or discharge faults caused by flash.

[0030] (4) The present invention adopts a composite wire mesh with a suspended double-layer orthogonal structure, and does in the resin matrix with oriented boron nitride whiskers and surface-modified nano-silica. The suspended structure reduces ineffective contact and stress concentration between wires, while the thermal bridge constructed by the boron nitride whiskers and the barrier layer formed by the nano-silica synergistically improve the thermal conductivity and oil swelling resistance of the material, so that the heat dissipation support node can quickly conduct the heat of the wire to the surface and be carried away by the oil. At the same time, the nanoparticles effectively prevent transformer oil molecules from penetrating into the resin. Compared with the shortcomings of the prior art, which has poor thermal conductivity and is prone to aging and swelling in high-temperature oil, resulting in a decline in mechanical properties, the present invention enhances the weather resistance and thermal stability of the wire insulation structure and extends the service life of the transformer under harsh conditions. Detailed Implementation

[0031] It should be noted that the grid-bound conductor and its single-sided reinforcement process for oil-immersed power transformers proposed in this invention aim to solve the technical problems of low heat dissipation efficiency, insufficient mechanical strength, and aging and swelling of insulation materials in hot oil environment faced by existing oil-immersed transformer conductors during long-term operation.

[0032] The sources of materials required for specific embodiments of this invention are as follows:

[0033] The load-bearing inner core uses high-strength glass fiber of model E6-CR produced by Jushi Group Co., Ltd., and its single filament diameter is strictly limited to 11μm.

[0034] The nano-silica used for resin matrix doping was purchased from Evonik Specialty Chemicals, with the grade AEROSIL R972 selected and the average particle size determined to be 30 nm.

[0035] The boron nitride whiskers that play a thermal conductive role in the resin matrix were purchased from Liaoning Kenuo New Materials Co., Ltd., with the grade BNW-1 and the aspect ratio determined to be 30.

[0036] The low-viscosity bisphenol F type epoxy resin base material was purchased from Nan Ya Electronic Materials Co., Ltd., model NPEF-170.

[0037] The closed-cell hollow microspheres used in the single-sided insulation reinforcement layer were purchased from Jinan Shengquan Group Co., Ltd., with the brand name PF-microspheres. Specifically, phenolic hollow microspheres with a foaming temperature of 120℃ and an average particle size of 30μm were selected.

[0038] The silane coupling agent KH-550 used for surface hydrophobic modification and the γ-glycidyl etheroxypropyltrimethoxysilane used for grafting were both purchased from Hubei Wuhan University Organosilicon New Materials Co., Ltd.

[0039] The carboxyl-terminated butadiene-acrylonitrile rubber liquid toughening agent used to construct the toughening phase of the island structure was purchased from Cardläne Corporation, USA, model CTBN1300X13; the latent curing agent dicyandiamide micro powder was purchased from Ningxia Jiafeng Chemical Co., Ltd.; the matching accelerator 2-ethyl-4-methylimidazolium was purchased from Sichuan Shengxiao Chemical Co., Ltd.; and the bisphenol A type epoxy resin used for the semi-cured insulating tape matrix was purchased from Guangzhou Hongchang Electronic Materials Co., Ltd., model EXA-850.

[0040] Regarding the conventional experimental solvents and basic reagents used in the preparation process of the examples, the solution used for ultrasonic cleaning of the load-bearing inner core is an acetone solution containing 0.5% sodium dodecylbenzenesulfonate by mass; the compound etching solution is prepared by mixing 6% hydrofluoric acid, 10% sulfuric acid, and 2% ammonium fluoride by mass; the alcohol-water solution used for surface grafting is a mixture of 1.5% γ-glycidyl etheroxypropyltrimethoxysilane, ethanol, and water, and the volume ratio of ethanol to deionized water in this mixture is kept constant at 9:1; the butanone solvent used to adjust the solid content of the insulating tape slurry is an analytical grade reagent with a purity greater than or equal to 99.5%; the thixotropic agent used in the insulating tape slurry to prevent the microspheres from floating and stratifying is AEROSIL200 fumed silica produced by Evonik Specialty Chemicals, and its specific addition amount is determined to be 1% of the total mass of the slurry.

[0041] In a preferred embodiment of the present invention, the load-bearing core of the composite wire mesh is made of high-strength glass fiber to solve the problem of interface slippage between the load-bearing core of the composite wire mesh and the resin matrix under long-term hot oil immersion environment.

[0042] Specifically, before resin coating the load-bearing core, the surface of the load-bearing core is roughened using a micro-etching process. The etching depth is controlled to form micro-scale mechanical anchor points on the surface of the load-bearing core. These mechanical anchor points are irregular pit structures with a specific depth. When the outer resin matrix cures, the resin molecular chains in the resin matrix penetrate deep into and wrap around the mechanical anchor points to form a three-dimensional interlock. The three-dimensional interlock structure built by the mechanical anchor points and the resin molecular chains of the resin matrix directly locks the interface, preventing relative displacement between the load-bearing core and the resin matrix under high-temperature conditions, and ensuring the structural integrity of the composite wire mesh when subjected to short-circuit electrodynamic forces.

[0043] Furthermore, the surface micro-etching of the load-bearing core specifically involves: The bundled load-bearing cores, with monofilament diameters between 9-13 μm, are ultrasonically cleaned for 15 minutes in an acetone solution bath containing surfactants to remove residual spinning oil and impurities from the fiber surface. They are then rinsed three times with deionized water. A compound etching solution is prepared, comprising 5%-8% hydrofluoric acid, 10% sulfuric acid, and 2% ammonium fluoride as a buffer. The cleaned load-bearing cores are passed through the etching tank at a speed of 2 m / min, with a dwell time controlled between 20 and 25 seconds. The hydrofluoric acid reacts chemically with the silica on the glass fiber surface, stripping away the glass phase from the surface layer. After the above... The aforementioned treatment creates irregular pits with a depth of 0.5 μm to 1.5 μm on the surface of the load-bearing core. These irregular pits serve as mechanical anchoring points. The depth of the load-bearing core surface is such that if it is less than 0.5 μm, the mechanical interlocking effect is not obvious, while if it is greater than 1.5 μm, it will damage the strength of the load-bearing core fiber. To prevent the surface of the etched load-bearing core fiber from re-adsorbing impurities, the load-bearing core must be immediately immersed in an alcohol-water solution containing 1.5% γ-glycidyl etheroxypropyltrimethoxysilane for surface grafting. After drying at 110°C for 10 minutes, one end of the silane coupling agent dehydrates and condenses with the hydroxyl groups on the surface of the load-bearing core fiber, while the other end retains epoxy groups to react with the resin matrix.

[0044] In this embodiment of the invention, to prevent transformer oil molecules from penetrating into the resin and causing swelling, nano-sized silica filler is introduced into the resin matrix. The particle size of the nano-silica is controlled between 10nm and 50nm and is surface-modified with the aforementioned silane coupling agent to ensure dispersibility. When transformer oil molecules attempt to penetrate into the heat dissipation support node, they must bypass the high-density nano-silica nanoparticle barrier layer, which extends the penetration path and reduces the diffusion coefficient. During high-temperature curing, a curing agent such as dicyandiamide or modified imidazole is used in conjunction with the high-temperature curing process, which enables the resin matrix to form a higher cross-linking density and increases the glass transition temperature. Furthermore, a physical sieving effect on power transformer oil molecules is formed in the gaps between resin molecular chain segments, abandoning the oil-proof strategy of relying on the surface fluorination layer in the prior art, which easily leads to subsequent adhesion failure.

[0045] In this embodiment, boron nitride whiskers are doped into the resin matrix. During the molding process of the heat dissipation support node, the flow field control causes the boron nitride whiskers to exhibit a directional arrangement trend from the contact surface of the conductor body to the outer surface of the heat dissipation support node inside the heat dissipation support node. This directional arrangement constructs a thermal bridge, which conducts the heat generated by the conductor body to the surface of the heat dissipation support node and is carried away by the transformer oil to improve the overall heat dissipation efficiency.

[0046] Specifically, the boron nitride whiskers and filled nano-silica in the resin matrix must undergo dispersion treatment before use. This involves: selecting boron nitride whiskers with an aspect ratio of 20-50 and placing them in a high-pressure reactor, adding isocyanate modifiers, and reacting at 80°C for 4 hours. Introducing amino functional groups onto the surface of the boron nitride whiskers solves the problem of the high inertness of the boron nitride surface and difficulty in wetting with epoxy resin; selecting nano-silica with a particle size of 20-40 nm and using a high-speed airflow pulverizer to disperse the aggregates while simultaneously spraying on a silane coupling agent KH-550 to hydrophobize the surface; and selecting low-viscosity bisphenol F type epoxy resin as the base material because it is hygroscopic at room temperature. The low viscosity facilitates the impregnation of high-density load-bearing cores. Pretreated nano-silica (8% by mass of the total resin) and boron nitride whiskers (12% by mass of the total resin) are added in batches to epoxy resin heated to 60°C. The mixture is dispersed for 30 minutes using a high-shear emulsifier at 5000 rpm to ensure that the nanoparticles do not agglomerate. To prevent the cured subcomposite wire from being too brittle, 5% by mass of terminal carboxyl butadiene nitrile rubber liquid toughening agent is added to the mixture and stirred for 1 hour to form a toughening phase with an island structure. The mixture is then cooled to 40°C and latent curing agents such as dicyandiamide micro powder and accelerators such as 2-ethyl-4-methylimidazolium are added to cure it into a resin matrix.

[0047] In this embodiment of the invention, the unilateral insulating reinforcement layer is a defoaming resin curing material containing micropores or composite hollow spheres, and the area where the heat dissipation support node is embedded in the unilateral insulating reinforcement layer is formed by local internal compression of the unilateral insulating reinforcement layer.

[0048] Specifically, the single-sided insulation reinforcement layer must be compressible, meaning that when compressed, its density increases while its volume decreases, rather than undergoing constant volume deformation like that of a fluid. In this embodiment, thermoplastic expandable microspheres or phenolic hollow microspheres are selected. The single-sided insulation reinforcement layer uses closed-cell hollow microspheres with an outer shell of acrylonitrile-vinylidene chloride copolymer and an inner layer of liquid isobutane. In the unfoamed state, the particle size is 10-15μm and the foaming temperature must be higher than the curing temperature of this process. Alternatively, pre-foamed closed-cell hollow microspheres with a particle size of 30-50μm can be directly selected. The compressive strength of the closed-cell hollow microspheres must be controlled between 0.5MPa and 2.0MPa. If the compressive strength is too high, the heat dissipation support node cannot be pressed in. If the compressive strength is too low, it may collapse and fail under the operating oil pressure of the transformer.

[0049] Furthermore, epoxy resin is dissolved in methyl ethyl ketone (MEK) solvent to adjust the solid content to 60%. 30% by mass of the aforementioned closed-cell hollow microspheres and an appropriate amount of thixotropic agent, such as fumed silica, are added to prevent the closed-cell hollow microspheres from floating and separating. The mixed slurry is then uniformly coated onto the release film using a precision slot coater, with the coating thickness controlled between 0.3 mm and 0.8 mm. The coated release film is then fed into a three-stage drying tunnel. In the first drying tunnel at 80°C, the solvent evaporates to prevent bubble formation. In the second drying tunnel at 110°C, a partial cross-linking reaction is initiated, increasing the molecular weight of the epoxy resin to achieve a non-sticky and flexible semi-cured state. In the third drying tunnel, the mixture is rapidly cooled to room temperature to stop the reaction. The resulting single-sided insulating reinforcement layer is filled with microcavities provided by the hollow microspheres, with an overall density of only 0.6-0.7 g / cm³, far lower than the 1.2 g / cm³ of ordinary epoxy castings.

[0050] In this embodiment of the invention, the sub-composite conductor is composed of a load-bearing core and a resin matrix. To prepare high-quality sub-composite conductors, a precise pultrusion impregnation process is required. The load-bearing core, which has undergone micro-etching treatment as described in the above embodiment, is placed on a constant tension pay-off frame. The tension of a single fiber bundle is controlled within the range of 4.8 to 5.2 N by adjusting the magnetic powder brake using a tension sensor feedback. Uneven tension can lead to uneven load distribution among the sub-composite conductors when the composite conductor mesh is under stress, causing early breakage. The load-bearing core is then placed in a vacuum impregnation tank containing the aforementioned resin matrix containing nano-silica and boron nitride whiskers. To ensure that the high-viscosity resin matrix adhesive can completely penetrate deep into the fiber bundles of the composite conductor, i.e., between the individual filaments, the impregnation tank is maintained at a vacuum of -0.08 MPa. After impregnation, the fiber bundles are passed through a set of precisely metered extrusion dies with the die aperture set to 110%-115% of the theoretical volume of the fiber bundle to scrape off excess resin and initially shape it into a circular cross-section. At this time, the resin content needs to be controlled at a mass fraction of 35%-40%. This content can balance insulation performance and mechanical strength. Too low a resin content will lead to micropores and reduce the withstand voltage level, while too high a resin content will reduce the overall modulus.

[0051] In this embodiment of the invention, the wire portion connecting the heat dissipation support node needs to maintain a certain degree of flexibility for braiding. Therefore, the entire wire cannot be completely cured; a partial molding curing process can be used. Specifically, the resin-impregnated sub-composite wire is placed into a specially designed molding machine. This machine is equipped with several opening and closing heating molds. The mold cavity is designed with an olive pit or microsphere structure. The inner wall of the mold cavity is not a smooth surface but is pre-engraved with a micron-level array of bumps by laser engraving. The specific bump height is 50-100μm and the spacing is 200-300μm. When the mold closes and holds the resin-impregnated sub-composite wire tightly, the above-mentioned bumps are pressed into the resin surface. After curing, an array of pit structures is transferred onto the surface of the heat dissipation support node. This structure can increase the friction coefficient when interlocking with the single-sided insulation reinforcement layer and reduce the simple The interlaminar shear force is converted into partial normal pressure; after the mold is closed, the temperature of the mold is instantly raised to 160℃-180℃ by the built-in high-power heating rod and maintained for 15-30 seconds. Since a latent curing agent is added to the resin matrix, the high temperature pulse is sufficient to stimulate the resin in the node area to undergo a cross-linking reaction, so that its curing degree quickly reaches more than 90% and its Shore hardness reaches more than 85, forming rigid hard points; and the ambient temperature of the conductor segment outside the mold is controlled below 60℃ by the cold air circulation system. At this temperature, the resin only undergoes an extremely slow reaction and remains in a semi-cured state. The conductor in this state has leather-like flexibility and can be bent or woven without breaking; after the above process, a sub-composite conductor with several rigid hard olive-shaped nodes distributed along the axial direction and flexible connections between the nodes is obtained.

[0052] Several sub-composite wires are arranged in parallel and laid on the surface of the main wire body. The spacing between adjacent sub-composite wires is controlled to be 5mm to 10mm using a servo cable laying machine. A second layer of sub-composite wires is laid vertically on top of the first layer of sub-composite wires. The laying speed of the second layer of sub-composite wires is dynamically adjusted according to the position of the heat dissipation support nodes on the first layer of sub-composite wires to ensure that the second layer of sub-composite wires is pressed onto the heat dissipation support nodes of the first layer of sub-composite wires. The first layer of sub-composite wires and the second layer of sub-composite wires are only spot-welded at the intersection of the heat dissipation support nodes to avoid damaging the internal fibers and maintain the structural rigidity of each heat dissipation support node.

[0053] Specifically, composite conductors refer to wires that are not fully cured but have a fiber-reinforced structure, unlike ordinary enameled wires which lack fiber reinforcement or fully cured fiberglass rods which lack flexibility.

[0054] A single-sided reinforcement process for mesh-bound conductors suitable for oil-immersed power transformers includes the following steps:

[0055] S1: Prepare an insulating tape in a semi-cured state with compressibility. The insulating tape contains a microbubble structure or a hollow microsphere structure.

[0056] S2: Apply radial pressure to one side of the conductor body that has been wrapped with composite wire mesh by covering the insulating tape. Use the fully cured heat dissipation support nodes on the composite wire mesh as rigid punches to forcefully press into the insulating tape in the semi-cured state.

[0057] S3: During the pressing process, the microbubble structure or hollow microsphere structure inside the insulation tape is broken or compressed to absorb the volume squeezed out by the heat dissipation support node in situ inside the insulation tape, preventing the resin from overflowing and forming flash.

[0058] S4: While maintaining radial pressure, heat the insulating tape and heat dissipation support nodes to change the insulating tape from a semi-cured state to a fully cured state.

[0059] In this embodiment of the invention, S1: The resin matrix is ​​mixed with filler containing microbubble structure or hollow microsphere structure to form a slurry, and the slurry is coated and baked to cause the resin matrix to undergo a preliminary cross-linking reaction to prepare an insulating tape in a semi-cured state.

[0060] The insulating tape, which is in a semi-cured state and has compressibility, is a specially formulated composite medium. A preferred insulating tape can be obtained by mixing a thermosetting epoxy resin matrix with a curing agent and an accelerator, and incorporating 20%-40% by volume closed-cell hollow microspheres. The semi-cured state specifically refers to coating the above-mentioned mixture onto release paper and baking it at 80℃-100℃ for 5-10 minutes to allow the resin to undergo a preliminary cross-linking reaction but without forming a three-dimensional network structure. At this point, the insulating tape exhibits flexibility and slight surface tackiness at room temperature, with its degree of curing controlled between 40%-60%. Specifically, in step S1, the insulating tape is prefabricated as a truss structure. The structure or porous structure retains macroscopic oil permeability holes after the in-situ press-fit interlocking structure is formed; the truss structure or porous structure is to solve the problem of heat dissipation obstruction that may occur after the insulation layer is covered. This structure is obtained by: using a precision punching die to pre-drill holes in the insulation tape when it is in a semi-cured state to form an array of through holes with a porosity of 15%-25%; or using 3D printing technology to directly print resin containing microspheres into a grid-like tape. After the in-situ press-fit interlocking structure is formed, even if the insulation reinforcement layer on one side covers the conductor, these reserved holes can still serve as macroscopic oil permeability holes, allowing transformer oil to directly contact the conductor body for heat exchange.

[0061] In this embodiment of the invention, S2: The insulating tape in a semi-cured state is covered on one side of the conductor body that has been wrapped with the composite wire mesh, and radial pressure is applied. The heat dissipation support node that has been fully cured on the composite wire mesh is used as a rigid punch to press into the insulating tape.

[0062] In step S2, the heat dissipation support node has been pre-cured. Specifically, the heat dissipation support node has been cured at high temperature by online molding during the preparation of the sub-composite conductor to achieve a Shore hardness of over 85 and a Young's modulus of over 3.0 GPa. At this time, the Shore hardness of the insulation tape in the semi-cured state should be controlled between 30 and 50. Forced indentation refers to using the hardness difference under radial pressure to force the low-hardness insulation tape to undergo plastic deformation due to the high-hardness heat dissipation support node. The preferred radial pressure is set to 0.5 MPa-2.0 MPa. The logic for setting this pressure value is that the pressure needs to be greater than the yield strength of the microbubble structure in the insulation tape to induce volume compression, but it needs to be less than the breaking strength of the load-bearing core to avoid crushing the internal fibers.

[0063] In this embodiment of the invention, S3: During the pressing process, the rupture or compression of the microbubble structure or hollow microsphere structure inside the semi-cured insulating tape causes the volume displaced by the heat dissipation support node to be absorbed in situ inside the semi-cured insulating tape.

[0064] Specifically, in step S3, volume reduction refers to the increase in density of the pressure area of ​​the insulating tape while the overall outline size of the insulating tape remains unchanged. In traditional processes, the volume displaced by a solid object pressed into a fluid or semi-fluid inevitably leads to a rise in the liquid level or overflow in all directions, resulting in flash. However, in this invention, the process control specifically requires that the total volume of microbubbles or hollow microspheres in the insulating tape within the pressure area be greater than or equal to the volume displaced by the heat dissipation support nodes. When pressure is applied, the hollow microspheres in the pressure area break or collapse, causing the air or gas in that area to be discharged or compressed. The space originally occupied by the microspheres is occupied by the embedded heat dissipation support nodes.

[0065] In this embodiment of the invention, S4 is to heat the semi-cured insulating tape and heat dissipation support node while maintaining radial pressure, so that the semi-cured insulating tape is transformed into a fully cured state to form a single-sided insulating reinforcement layer.

[0066] Specifically, in step S4, the connection interface formed after the insulating tape and the heat dissipation support node are fully cured has shear resistance. The shear resistance is provided by the tenon structure formed by the single-sided insulating reinforcement layer embedded in the insulating tape by the heat dissipation support node. The pressed insulating tape is sent into a curing oven and cured at 130℃-150℃ for 2-4 hours. During this process, the epoxy resin in the insulating tape undergoes a cross-linking reaction and changes from semi-cured to fully cured. At the same time, the resin matrix of the insulating tape and the residual active groups on the surface of the heat dissipation support node undergo chemical bonding to achieve co-curing.

[0067] Example 1:

[0068] This embodiment uses the preferred process parameters of the present invention for preparation, and the specific steps are as follows:

[0069] High-strength glass fiber was selected as the load-bearing core of the sub-composite conductor, and its surface was micro-etched. Modified epoxy resin was used as the resin matrix, and olive-shaped heat dissipation support nodes were formed on the load-bearing core using an online molding process. Before weaving, the heat dissipation support nodes were pre-cured at high temperature to ensure complete curing, and their Shore hardness was measured to be 92. The insulation tape matrix in a semi-cured state was prepared by uniformly doping 30% phenolic resin hollow microspheres with an average particle size of 30 μm with bisphenol A epoxy resin. The resulting insulation tape had compressibility and an initial density of approximately 0.75 g / cm³. The insulation tape was then placed on one side of the conductor body wrapped with the composite conductor mesh. A radial pressure of 1.5 MPa was applied, and the fully cured heat dissipation support nodes were used as rigid punches to forcefully press into the insulation tape. During this process, the insulation tape achieved volume reduction and controlled resin overflow through microsphere rupture. Subsequently, it was cured at 140℃ for 3 hours under pressure.

[0070] Example 2:

[0071] This embodiment aims to verify the lower limit of volume absorption. The only difference from Embodiment 1 is that the volume fraction of hollow microspheres doped inside the semi-cured insulating tape is reduced to 10%, while the other materials, structures and process parameters are completely consistent with Embodiment 1.

[0072] Example 3:

[0073] The only difference between this embodiment and Embodiment 1 is that the heat dissipation support node is designed as a positive microsphere structure with a sphericity greater than 0.98 and a diameter consistent with the maximum diameter of the olive pit-shaped node. The remaining materials, structures, and process parameters are completely consistent with Embodiment 1.

[0074] Example 4:

[0075] The only difference between this embodiment and Embodiment 1 is that, after the semi-cured insulating tape is prepared into a semi-cured sheet, it is prefabricated into a porous structure by precision mechanical punching with a porosity of 15%. The heat dissipation support nodes are pressed into the solid area to absorb the volume using microspheres. The remaining materials and process parameters are completely consistent with those of Embodiment 1.

[0076] Comparative Example 1:

[0077] This comparative example aims to simulate the traditional solid material pressing process. The only difference from Example 1 is that the insulating tape is a solid semi-cured resin tape without any microbubbles or hollow microspheres, with a density of 1.25 g / cm³ that is incompressible. All other materials, structures, and process parameters are completely consistent with Example 1.

[0078] Comparative Example 2:

[0079] The only difference between this comparative example and Example 1 is that the heat dissipation support node was not pre-cured and was in a semi-cured state with a hardness of less than 40 before being pressed in. The heat dissipation support node and the insulating tape deformed simultaneously. The other materials, structures and process parameters are completely consistent with those of Example 1.

[0080] Comparative Example 3:

[0081] The only difference between this comparative example and Example 1 is that the heat dissipation support node is designed as a cylindrical shape, i.e., a straight cylinder without a central bulge or undercut structure. The heat dissipation support node is pre-cured to a Shore D hardness of 92. All other materials, structures, and process parameters are completely consistent with Example 1.

[0082] Comparative Example 4:

[0083] This comparative example aims to verify the thermal conductivity gain of boron nitride whiskers doped in the resin matrix. The only difference from Example 1 is that boron nitride whiskers are removed from the resin matrix formulation, and the missing mass fraction is replaced by an equal amount of bisphenol F type epoxy resin. The remaining materials, structures and process parameters are completely consistent with Example 1.

[0084] Comparative Example 5:

[0085] This comparative example aims to verify the oil swelling resistance gain of filled nano-silica. The only difference from Example 1 is that the surface-modified nano-silica is removed from the resin matrix formulation, and the missing mass fraction is replaced by an equal amount of bisphenol F type epoxy resin. The remaining materials, structures and process parameters are completely consistent with Example 1.

[0086] Comparative Example 6:

[0087] This comparative example aims to verify the mechanical interlocking gain brought about by the array of pits on the surface of the heat dissipation support node. The only difference from Example 1 is that the inner wall of the locally molded and cured heating mold of the heat dissipation support node is a smooth surface, and the surface of the heat dissipation support node after complete curing has no array of pits. The other materials, structures and process parameters are completely consistent with Example 1.

[0088] Comparative Example 7: This comparative example aims to verify the anti-slip gain of the mechanical anchor points constructed by the micro-etching process. The only difference from Example 1 is that the load-bearing core of the sub-composite conductor was not subjected to micro-etching treatment with the compound etching solution before resin coating, and the surface of the load-bearing core does not have mechanical anchor points formed by micro-etching. The other materials, structures and process parameters are completely consistent with Example 1.

[0089] Performance testing methods:

[0090] For the samples prepared in the above embodiments and comparative examples, deformation characteristics and mechanical tests, thermal stability tests, chemical stability tests, and interfacial mechanical tests were performed:

[0091] Specifically, a high-precision image measuring instrument is used to scan along the interface between the heat dissipation support node and the single-sided insulation reinforcement layer, and the maximum vertical height of the resin overflow interface reference plane, i.e., the flash height, is measured. The sample is fixed on a universal testing machine, and a thrust is applied to the single-sided insulation reinforcement layer along the axial direction of the conductor body until the in-situ press-fit interlocking structure is destroyed, and the maximum load, i.e., the axial shear force, is recorded. The transient plane heat source method is used to measure and record the thermal conductivity of the fully cured resin matrix standard sample. The sample containing the in-situ press-fit interlocking structure is completely immersed in mineral insulating transformer oil at 130°C for continuous aging for 720 hours. After being taken out, cleaned, and allowed to cool to room temperature, it is fixed on a universal testing machine to test the axial shear force after aging, and the shear force retention rate before and after thermal aging is calculated. A sub-composite conductor standard sample containing a complete heat dissipation support node is cut off, and the resin matrix and the load-bearing core are peeled off using a microelectromechanical tensile and compressive testing platform. The maximum load at the time of peeling failure is recorded, and the shear strength of the interface between the resin matrix and the load-bearing core is calculated.

[0092] The experimental results are shown in Table 1:

[0093] Group Flash height / mm Axial shear resistance / N Thermal conductivity / (W / (m·K)) Shear strength retention rate after hot oil immersion / % Shear strength at the interface between the resin matrix and the load-bearing inner core (MPa) Example 1 0.05 1480 0.85 93.2 46.5 Example 2 0.42 1350 0.85 92.8 46.2 Example 3 0.06 1410 0.85 93.1 46.8 Example 4 0.02 1450 0.85 93.5 46.4 Comparative Example 1 2.85 920 0.85 92.5 46.6 Comparative Example 2 0.08 680 0.85 90.4 46 Comparative Example 3 0.05 950 0.85 92.7 46.5 Comparative Example 4 0.05 1470 0.25 91.8 46.6 Comparative Example 5 0.05 1460 0.83 75.6 46.1 Comparative Example 6 0.05 1120 0.85 93 46.5 Comparative Example 7 0.05 1470 0.85 92.9 21.3

[0094] Analysis of experimental results:

[0095] Based on the analysis of the above embodiments and comparative examples, the data of Example 3 shows that the micro-spherical heat dissipation support node can also achieve micro-flash embedding, and the shear resistance is close to that of the olive pit-shaped node, both of which are much higher than the straight cylindrical node in Comparative Example 3. This proves that both the olive pit-shaped and micro-spherical structures used in this invention can form an effective mortise and tenon structure.

[0096] All experimental groups using insulating tape containing closed-cell hollow microspheres (Examples 1, 3, and 4) had flash heights controlled below 0.1 mm, limiting resin overflow to an extremely low level. In contrast, Comparative Example 1, using solid material, had flash heights as high as 2.85 mm. This demonstrates that the semi-cured insulating tape containing closed-cell hollow microspheres achieves the function of microsphere rupture or compression densification under pressure to absorb the displaced volume in situ, thus preventing resin overflow and flash formation. Examples 1 to 4 used semi-cured insulating tape containing microbubble or hollow microsphere structures to prepare single-sided... The flash height of the insulating reinforcement layer is limited to 0.42 mm or less. In particular, Example 4 further reduces the flash height to 0.02 mm by using a prefabricated porous structure, while Comparative Example 1 uses a solid semi-cured resin tape, resulting in a flash height as high as 2.85 mm. This data difference reveals the technical feature that the single-sided insulating reinforcement layer contains a hollow microsphere structure. When the single-sided insulating reinforcement layer is compressed, the microspheres rupture or collapse to generate densification, thereby absorbing the displaced volume in situ. This brings about the technical effect of fundamentally preventing the resin from flowing out to the surroundings and forming flash during the pressing process, thus ensuring the smooth flow of heat dissipation oil channels.

[0097] Example 1 exhibits a thermal conductivity of 0.85 W / m Kelvin and a shear strength retention rate of 93.2%, while Comparative Example 4, without added boron nitride whiskers, has a thermal conductivity of only 0.25 W / m Kelvin. Comparative Example 5, without added nano-silica, shows a significant decrease in shear strength retention rate to 75.6% after immersion in hot transformer oil. This data comparison quantifies the technical gains brought about by material modification and objectively confirms that the technical feature of doping boron nitride whiskers and filling nano-silica inside the resin matrix enables the construction of thermal bridges and the formation of a barrier layer, thereby improving thermal conductivity and resistance to transformer oil swelling.

[0098] The axial shear strength of Example 1 reached 1480 Newtons, while that of Comparative Example 6 was only 1120 Newtons. This difference in data confirms that the technical feature of the surface of the heat dissipation support node being covered with an array of pits increases the friction coefficient of the interface of the in-situ press-fit interlocking structure, thereby converting the simple interlaminar shear force into part of the normal pressure and thus improving the mechanical anchoring strength against short-circuit electrostatic forces. At the same time, the shear strength of the interface between the resin matrix and the load-bearing core in Example 1 reached 46.5 MPa, while that of Comparative Example 7 was only 21.3 MPa. This precipitous data comparison confirms that the technical feature of the surface of the load-bearing core having mechanical anchoring points formed by micro-etching enables the resin molecular chains in the resin matrix to penetrate deep into the pores and form a three-dimensional interlocking function, thereby locking the interface between the load-bearing core and the resin matrix and preventing the sub-composite wire from undergoing internal interlaminar slippage failure under long-term hot oil immersion.

[0099] Comparing the axial shear force data of Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 6, the axial shear force of Example 1 reached 1480N, while the shear force of Comparative Example 2, which did not have a pre-cured heat dissipation support node, dropped to 680N. The shear force of Comparative Example 3, which used a cylindrical node, dropped to 950N, and the shear force of Comparative Example 6, which had no pits on the surface of the heat dissipation support node, dropped to 1120N. The above results confirm the technical features of pre-curing the heat dissipation support node to make its hardness greater than that of the insulation tape in a semi-cured state and designing it as an olive pit-shaped or micro-spherical structure with a surface array of pits. This enables the high-hardness heat dissipation support node to function as a rigid punch embedded inside the insulation tape to form an in-situ press-fit interlocking structure and a tenon and mortise structure. This results in an increase in the friction coefficient of the bonding interface and transforms the interlayer chemical adhesion into normal pressure and mechanical interlocking force, thereby significantly improving the shear resistance and preventing the winding conductors from undergoing relative displacement when subjected to short-circuit electrodynamic impact.

[0100] Observing the thermal and chemical stability test data of Example 1 and Comparative Examples 4 and 5, the thermal conductivity of the fully cured resin matrix of Example 1 was 0.85 W / (m·K) and the shear strength retention rate after immersion in hot transformer oil reached 93.2%. The lack of boron nitride whiskers in Comparative Example 4 caused the thermal conductivity to drop to 0.25 W / (m·K), and the lack of nano-silica in Comparative Example 5 caused the shear strength retention rate to decrease to 75.6%. This data verifies the technical feature that the resin matrix of the sub-composite conductor is doped with boron nitride whiskers and filled with nano-silica. It realizes the function of using boron nitride whiskers to construct directional thermal bridges pointing to the outer surface of the heat dissipation support node and using nano-silica to form a nanoparticle barrier layer that blocks the penetration of transformer oil molecules. This brings about the technical effect of synergistically improving the thermal conductivity and oil swelling resistance of the composite conductor grid, and avoids the mechanical properties of the resin aging in high-temperature oil.

[0101] Regarding the test results of the shear strength at the interface between the resin matrix and the load-bearing core, the data of Example 1 is as high as 46.5 MPa, while the strength of Comparative Example 7, whose load-bearing core has not undergone micro-etching treatment, is only 21.3 MPa. This precipitous data comparison clearly illustrates the technical feature that the surface of the load-bearing core of the sub-composite conductor has mechanical anchoring points formed by micro-etching. This enables the resin molecular chains in the resin matrix to penetrate deep into the surface pits to form a three-dimensional interlocking structure, resulting in the technical effect of directly locking the interface between the load-bearing core and the resin matrix, thereby preventing interlayer slippage of the sub-composite conductor under long-term hot oil immersion.

[0102] The present invention has verified the reliability of its technical solution under different implementation forms through multiple sets of experiments, and proved that it has outstanding substantive features and significant progress compared with the prior art. Based on the ideal embodiment of the present invention, and through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

[0103] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A mesh-bundled conductor suitable for oil-immersed power transformers, comprising: The conductor body, the composite conductor grid wrapped around the outer periphery of the conductor body, and the single-sided insulation reinforcement layer disposed on one side of the conductor body are characterized in that: The composite wire mesh is formed by laying several sub-composite wires orthogonally, and the sub-composite wires are distributed with several independently formed heat dissipation support nodes at intervals along the axial direction. The sub-composite conductor includes a load-bearing inner core and a resin matrix covering the load-bearing inner core; An in-situ press-fit interlocking structure is formed between the single-sided insulating reinforcement layer and the composite wire mesh. The in-situ press-fit interlocking structure refers to the heat dissipation support node being at least partially embedded in the thickness direction of the single-sided insulating reinforcement layer as a rigid punch, and the heat dissipation support node and the single-sided insulating reinforcement layer having a zero-gap co-curing connection interface.

2. The mesh-bound conductor for oil-immersed power transformers according to claim 1, characterized in that: The heat dissipation support node has an olive pit or microsphere-like structure, and the surface of the heat dissipation support node is covered with an array of pit structures.

3. A mesh-bound conductor suitable for oil-immersed power transformers according to claim 1, characterized in that: The load-bearing core is made of high-strength glass fiber, and the surface of the load-bearing core has mechanical anchoring points formed by micro-etching. The resin matrix is ​​a fully cured, highly cross-linked modified epoxy resin, the resin matrix is ​​doped with boron nitride whiskers, and the resin matrix is ​​filled with nano-silica.

4. A mesh-bound conductor suitable for oil-immersed power transformers according to claim 1, characterized in that: The single-sided insulating reinforcement layer is a defoaming resin curing material containing micropores or composite hollow spheres, and the area where the heat dissipation support node is embedded in the single-sided insulating reinforcement layer is formed by local internal compression and accommodation of the single-sided insulating reinforcement layer.

5. A mesh-bundled conductor suitable for oil-immersed power transformers according to claim 1, characterized in that: The composite wire mesh is a suspended double-layer orthogonal structure, which includes a first layer of sub-composite wires laid in parallel longitudinal direction and a second layer of sub-composite wires laid in a lateral circular direction. The first layer of sub-composite wires and the second layer of sub-composite wires are only bonded together by spot welding at the intersection of the heat dissipation support node.

6. A single-sided reinforcement process for mesh-bound conductors suitable for oil-immersed power transformers, characterized in that, Includes the following steps: S1: The resin matrix is ​​mixed with fillers containing microbubble structure or hollow microsphere structure to form a slurry. The slurry is then coated and baked to allow the resin matrix to undergo a preliminary cross-linking reaction, thus preparing an insulating tape in a semi-cured state. S2: Cover one side of the conductor body that has been wrapped with composite wire mesh with the semi-cured insulation tape and apply radial pressure. Use the fully cured heat dissipation support nodes on the composite wire mesh as rigid punches to press into the insulation tape. S3: During the pressing process, the rupture or compression of the microbubble structure or hollow microsphere structure inside the semi-cured insulation tape is used to promote the in-situ absorption of the volume displaced by the heat dissipation support node inside the semi-cured insulation tape. S4: While maintaining radial pressure, heat the semi-cured insulation tape and heat dissipation support node to transform the semi-cured insulation tape into a fully cured state, thereby forming a single-sided insulation reinforcement layer.

7. The single-sided reinforcement process for mesh-bound conductors suitable for oil-immersed power transformers according to claim 6, characterized in that, In step S1, the resin matrix is ​​a thermosetting epoxy resin matrix, the slurry also contains a curing agent and an accelerator, and the filler is a closed-cell hollow microsphere with a volume fraction of 20%-40%. The baking process is controlled within a temperature range of 80℃-100℃ for five to ten minutes, so that the resin matrix undergoes a preliminary cross-linking reaction but does not form a three-dimensional network structure, and the degree of curing of the semi-cured insulation tape is controlled between 40% and 60%.

8. The single-sided reinforcement process for mesh-bound conductors suitable for oil-immersed power transformers according to claim 6, characterized in that, In step S2, the heat dissipation support node has been pre-cured, and its hardness is greater than that of the insulating tape in a semi-cured state. The radial pressure is set to 0.5MPa-2.0MPa. The radial pressure is greater than the yield strength of the microbubble structure in the semi-cured insulation tape and less than the destructive strength of the load-bearing core in the composite conductor grid.

9. The single-sided reinforcement process for mesh-bound conductors suitable for oil-immersed power transformers according to claim 6, characterized in that, In step S3, the total volume of the insulating tape containing microbubble structures or hollow microsphere structures in the semi-cured state within the pressure area is greater than or equal to the volume displaced by the heat dissipation support node. The microbubble or hollow microsphere structure in the pressure area breaks or collapses, which increases the density of the pressure area of ​​the insulation tape in the semi-cured state while keeping the overall outline size unchanged.

10. A single-sided reinforcement process for mesh-bound conductors suitable for oil-immersed power transformers according to claim 6, characterized in that, In step S4, the heating process involves constant temperature curing at 130℃-150℃ for two to four hours; The resin matrix of the insulating tape in a semi-cured state undergoes chemical bonding with the residual active groups on the surface of the heat dissipation support node to achieve co-curing. The shear resistance of the connection interface formed after complete curing is provided by the tenon structure formed by the single-sided insulating reinforcement layer embedded in the insulating tape by the heat dissipation support node.