A heat-resistant aluminum alloy 10kV overhead insulated conductor and its manufacturing method

Abstract

This invention discloses a heat-resistant aluminum alloy 10kV overhead insulated conductor and its manufacturing method, belonging to the technical field of overhead conductor manufacturing. It includes a conductor, a shielding layer, and an insulation layer. The shielding layer is located on the outside of the conductor, and the insulation layer is located on the outside of the shielding layer. The conductor is a compacted circular conductor formed by stranding aluminum alloy single wires, consisting of 37 strands in a 1+6+12+18 stranding structure. The shielding layer is formed by wrapping metal wire and is located on the outside of the conductor. The insulation layer is made of cross-linked polyethylene material and is located on the outside of the shielding layer through extrusion. This invention uses a compacted circular conductor formed by stranding 37 aluminum alloy single wires in a 1+6+12+18 structure, and employs heat-resistant aluminum alloy single wires containing Fe, Zr, and B elements as the conductor material, improving the long-term current-carrying capacity and structural stability of the conductor, meeting the requirements of line capacity expansion and high-load continuous operation.

Description

Technical Field

[0001] This invention relates to a heat-resistant aluminum alloy 10kV overhead insulated conductor and its manufacturing method, belonging to the field of overhead conductor manufacturing technology. Background Technology

[0002] In 10kV overhead distribution lines, urban distribution network upgrades, capacity expansion of aging lines, and medium-voltage power transmission and distribution scenarios in complex outdoor environments, these conductors are typically exposed to long-term environmental conditions such as sunlight, wind, rain, temperature variations, ultraviolet radiation, and mechanical vibration. They also need to continuously transmit electrical energy over a certain span, thus placing high demands on the conductor materials' heat resistance, creep resistance, current carrying capacity, insulation reliability, and long-term operational stability. With the increasing load on distribution networks and the growing demand for distributed power generation, 10kV overhead insulated conductors not only need to meet basic conductivity requirements but also need to possess good high-temperature operating capabilities and a long service life.

[0003] Currently, 10kV overhead insulated conductors generally use pure aluminum conductors or conventional aluminum alloy conductors, with an outer cross-linked polyethylene insulation layer to form an insulated transmission structure. This type of conductor has advantages in actual production and use, such as mature technology, low cost, and wide application, and can meet the basic usage requirements of general power distribution lines.

[0004] However, existing technologies still have significant shortcomings: conventional pure aluminum or ordinary aluminum alloy conductors have limited heat resistance and creep resistance, and are prone to softening, increased sag, and decreased structural stability under high-temperature and heavy-load conditions, resulting in limited current-carrying capacity and difficulty in meeting the demands of line capacity expansion and long-term high-load operation. Insufficient structural matching between the conductor and insulation layer, and poor conductor circumference roundness and surface uniformity, can easily lead to eccentricity, air gaps, or localized defects during insulation extrusion, thus affecting insulation reliability and long-term operational safety. Conventional insulation layers are susceptible to aging due to ultraviolet radiation, temperature fluctuations, and external environmental factors during long-term outdoor operation, limiting their service life and operational stability. For the renovation and capacity expansion of old lines, existing conductors often struggle to simultaneously meet capacity increase requirements while also ensuring structural stability, construction adaptability, and overall life-cycle economic efficiency.

[0005] Therefore, it is necessary to design a heat-resistant aluminum alloy 10kV overhead insulated conductor and its manufacturing method to solve the above problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a heat-resistant aluminum alloy 10kV overhead insulated conductor and its manufacturing method, which solves the problems of being unsuitable for line operation, easy defects in conductor and insulation layer, and being greatly affected by the environment.

[0007] The technical problem to be solved by this invention is achieved by the following technical solution: a heat-resistant aluminum alloy 10kV overhead insulated conductor. It includes a conductor, a shielding layer, and an insulating layer, wherein the shielding layer is disposed on the outside of the conductor, and the insulating layer is disposed on the outside of the shielding layer; The conductor is a compacted circular conductor formed by stranding aluminum alloy single wires. The conductor is composed of 37 stranded single wires with a stranding structure of 1+6+12+18. The shielding layer is formed by wrapping metal wires and is disposed on the outside of the conductor by wrapping. The insulating layer is made of cross-linked polyethylene material and is extruded onto the outside of the shielding layer.

[0008] Preferably, the aluminum alloy single wire has the following composition by weight percentage: Fe 0.60%~0.80%, Zr 0.08%~0.12%, B 0.01%~0.03%, Si≤0.10%, and the remainder is Al.

[0009] Preferably, the single wire diameter of the conductor is φ3.07mm, and the compaction coefficient of the conductor is not less than 0.92.

[0010] Preferably, the shielding layer is formed by wrapping copper wire.

[0011] Preferably, the insulating layer is a cross-linked polyethylene insulating layer, and the thickness of the insulating layer is not less than 3.4 mm.

[0012] A method for manufacturing a heat-resistant aluminum alloy 10kV overhead insulated conductor, preferably comprising: S1. Aluminum alloy smelting and rod making: Smelting aluminum alloys according to preset compositions and making aluminum alloy rods; S2. Wire drawing: Drawing the aluminum alloy rod into a single wire; S3. Heat treatment: Stabilize the single wire with heat treatment; S4. Stranding and compaction: The 37 single wires are stranded and compacted in a 1+6+12+18 structure to form a circular conductor; S5. Shielding layer configuration: A shielding layer is formed by wrapping metal wire around the outside of the conductor; S6. Extrusion of insulation layer: Extruding a cross-linked polyethylene insulation layer on the outside of the shielding layer and performing cross-linking shaping treatment.

[0013] Preferably, in step S2, a multi-pass wire drawing process is used to form a single line with a smooth surface.

[0014] Preferably, step S3 includes a stress relief treatment.

[0015] Preferably, in step S6, the conductor is preheated at 100°C-120°C before extrusion.

[0016] The beneficial effects of this invention are: This invention employs a compacted circular conductor formed by stranding 37 aluminum alloy single wires in a 1+6+12+18 configuration, using heat-resistant aluminum alloy single wires containing Fe, Zr, and B elements as the conductor material. This achieves good structural stability and creep resistance in the conductor under high-temperature operating conditions. The conductor is less prone to softening, deformation, and structural degradation under long-term high-temperature current-carrying conditions, thereby reducing the sag increase caused by conductor creep during line operation, improving the long-term current-carrying capacity and structural stability of the conductor, and meeting the requirements of line capacity expansion and continuous high-load operation.

[0017] This invention establishes a compacted circular conductor structure and controls the conductor compaction coefficient to be no less than 0.92, thereby reducing the gap in the conductor cross-section and improving the roundness of the outer contour. During the compaction process, the individual wires in each layer adhere to each other and form a regular circular outer contour, improving the flatness of the conductor's outer surface and reducing unevenness on the stranded conductor surface. This provides a stable foundation for subsequent shielding layer wrapping and insulation layer extrusion, reducing problems such as insulation layer eccentricity, local over-thickness, local over-thinness, and uneven coverage, and improving the overall structural consistency and product quality stability of the conductor.

[0018] This invention provides a shielding layer formed by wrapping metal wires around the conductor, positioned between the conductor and the insulation layer, thus achieving a structural transition between them. The shielding layer covers the localized undulations formed by the single wires around the conductor, creating a more uniform and continuous coating interface. This improves the uniformity of the coating during the insulation extrusion process, reduces the probability of air gaps, voids, and localized defects within the insulation layer, and enhances the reliability and long-term operational safety of the insulation structure.

[0019] This invention utilizes a cylindrical covering structure formed by continuous wrapping of copper wire in the shielding layer, achieving a tight fit between the shielding layer and the outer periphery of the conductor. Copper wire possesses good flexibility and wrapping adaptability, maintaining a stable wrapping state during continuous production. This ensures the shielding layer forms a continuous and uniform covering along the conductor's axial direction, thereby improving the quality of subsequent insulation layer formation and enhancing the overall stability and consistency of the conductor structure.

[0020] This invention employs a production process that combines conductor preheating, shielding layer wrapping, and cross-linked polyethylene extrusion, achieving a stable bond between the conductor, shielding layer, and insulation layer. Preheating the conductor to 100℃~120℃ before extrusion reduces the temperature difference between the conductor and insulation material, improves the bonding quality between the insulation and shielding layers, and lowers the probability of bubbles, delamination, and localized defects, thereby enhancing the insulation uniformity and overall structural stability of the finished conductor. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] In the diagram: 1-conductor, 2-shielding layer, 3-insulating layer. Detailed Implementation

[0023] To facilitate a clear understanding of the technical means, creative features, objectives, and effects of this invention, the invention will be further described below in conjunction with specific embodiments. Example 1

[0024] like Figure 1 As shown, a heat-resistant aluminum alloy 10kV overhead insulated conductor includes a conductor 1, a shielding layer 2, and an insulation layer 3. The shielding layer 2 is disposed on the outside of the conductor 1, and the insulation layer 3 is disposed on the outside of the shielding layer 2.

[0025] Conductor 1 is a compacted circular conductor formed by stranding single aluminum alloy wires. Conductor 1 consists of 37 stranded single wires with a stranding structure of 1+6+12+18.

[0026] The shielding layer 2 is formed by wrapping metal wire and is placed on the outside of the conductor 1 by wrapping.

[0027] The insulation layer 3 is made of cross-linked polyethylene material and is set on the outside of the shielding layer 2 by extrusion.

[0028] like Figure 1 As shown, the overhead insulated conductor adopts a coaxial layered cylindrical structure extending along its axis. Its cross-section is distributed in concentric layers, comprising, from the inside out, a conductor 1, a shielding layer 2, and an insulation layer 3. The conductor 1 is located at the innermost layer and forms the metallic conductive body of the conductor. The shielding layer 2 covers the outer periphery of the conductor 1 and is coaxially arranged with it. The insulation layer 3 covers the outer periphery of the shielding layer 2 and forms the outermost protective layer. These three layers are stacked radially to form a continuous, regularly shaped cylindrical overhead insulated conductor.

[0029] Conductor 1 is a circular conductor structure formed by tightly pressing together stranded aluminum alloy single wires. Conductor 1 consists of 37 aluminum alloy single wires, with an overall stranding structure of 1+6+12+18. At the very center is a single central wire, surrounded by 6 single wires, then 12 single wires, and finally 18 single wires. Each layer of single wires is arranged spirally along the conductor's axis, with adjacent single wires close together. After stranding, a tight pressing process transforms the cross-section of conductor 1 from an approximately polygonal outline in the stranded state to a perfectly round, tightly pressed circle. This circular structure improves the uniformity of the conductor 1's outer perimeter, reduces gaps formed after stranding, and provides a stable shape foundation for the subsequent wrapping of the shielding layer 2 and extrusion of the insulation layer 3.

[0030] The single wire in conductor 1 is made of heat-resistant aluminum alloy with a diameter of φ3.07mm. In this embodiment, the single wire in conductor 1 is made of 8176 heat-resistant aluminum alloy. 8176 heat-resistant aluminum alloy comprises, by mass percentage: Fe 0.60%–0.80%, Zr 0.08%–0.12%, B 0.01%–0.03%, Si ≤0.10%, with the remainder being Al and unavoidable impurities. This alloy system improves the high-temperature structural stability of the material through the synergistic effect of Fe, Zr, and B, enabling the single wire to maintain good strength retention and creep resistance even with long-term elevated operating temperatures. It is suitable as a conductor material for 10kV overhead insulated conductors, making conductor 1 less prone to significant softening and creep during long-term current carrying. Before entering the stranding process, each single wire undergoes wire drawing and stabilization heat treatment. The surface of the single wire remains flat after drawing, and the diameter of the single wire is stable. After heat treatment, the residual stress inside the single wire is released, and the single wire is less likely to exhibit obvious springback, warping, or local twisting during subsequent stranding.

[0031] Conductor 1 adopts a compacted circular structure with a compaction coefficient of not less than 0.92. This compaction process further solidifies the arrangement of the individual wires within the conductor, resulting in tighter contact between the wires, a more circular overall cross-section, and a smoother outer surface. After compaction, the outer perimeter of conductor 1 no longer exhibits obvious polygonal edges, but instead forms a relatively smooth circular outline. This circular outline not only improves the uniformity of the conductor's outer surface but also provides a stable foundation for the subsequent wrapping of the shielding layer 2 and the extrusion of the insulation layer 3, reducing thickness fluctuations caused by uneven outlines between subsequent layers.

[0032] The shielding layer 2 is disposed on the outside of the conductor 1 and is arranged coaxially with the conductor 1. The shielding layer 2 is formed by wrapping metal wire, and in this embodiment, copper wire is used. The shielding layer 2 is formed by continuously wrapping copper wire around the outer circumference of the conductor 1 in a spiral manner. After wrapping, the shielding layer 2 is a cylindrical metal cladding layer, which is coaxially arranged with the outer circumference of the conductor 1. During the copper wire wrapping process, the copper wire extends continuously along the conductor axis, and the wrapping loops are adjacent to each other or partially overlap, forming a relatively stable outer cladding layer. Structurally, the shielding layer 2 is located between the conductor 1 and the insulation layer 3, and can act as a transition layer on the outer circumference of the conductor 1, making the outer circumference surface of the conductor 1 smoother and reducing the interference of exposed edges or local protrusions of the conductor wires during the subsequent extrusion molding of the insulation layer 3.

[0033] The shielding layer 2 is a cylindrical wrapping layer whose shape matches the outer contour of the conductor 1. After wrapping, the overall structure remains coaxial and cylindrical. This layer is located between the conductor 1 and the insulation layer 3. On the one hand, it makes the outer surface of the conductor 1 smoother, and on the other hand, it provides a relatively uniform base layer for the extrusion of the insulation layer 3, making it easier to achieve a consistent coating thickness and stable adhesion during the forming process. When the shielding layer 2 is formed using copper wire, the copper wire has good flexibility and wrapping adaptability, which facilitates maintaining wrapping stability and interlayer continuity during continuous production.

[0034] Insulation layer 3 is disposed on the outside of shielding layer 2 and covers the outer periphery of shielding layer 2. Insulation layer 3 is made of cross-linked polyethylene material and formed by extrusion. After being melted and plasticized, the cross-linked polyethylene material is continuously extruded through a mold, uniformly covering the outer periphery of shielding layer 2 to form a continuous, seamless outer insulating covering structure. The thickness of insulation layer 3 is not less than 3.4 mm to meet the electrical insulation requirements of 10kV overhead insulated conductors and the mechanical protection requirements in outdoor environments. After molding, insulation layer 3 undergoes cross-linking and shaping treatment to form a stable cross-linked network structure inside the material, thereby improving the heat resistance, environmental aging resistance, and dimensional stability of insulation layer 3.

[0035] Insulation layer 3 is applied to the outside of shielding layer 2 via extrusion. After extrusion, insulation layer 3 forms a continuous and uniform cylindrical coating with a smooth outer surface, extending continuously along the conductor axis. During extrusion, molten cross-linked polyethylene material is plasticized in the extruder and then uniformly coated onto the outer periphery of shielding layer 2 through a die, forming a continuous and seamless insulating coating. After molding, insulation layer 3 undergoes further cross-linking and shaping treatment to form a stable cross-linked network within the insulating material, thereby improving the heat resistance, stress cracking resistance, and long-term service stability of insulation layer 3. After cross-linking, the mechanical strength and dimensional stability of insulation layer 3 are further improved, making it less prone to significant performance degradation due to temperature changes, ultraviolet radiation, or external friction during overhead operation.

[0036] In this embodiment, conductor 1, shielding layer 2, and insulation layer 3 are arranged coaxially in sequence, forming a layered structure that covers the conductor from the inside out. Conductor 1 carries the current, shielding layer 2 provides the outer transition and basic covering for the conductor, and insulation layer 3 provides external insulation protection. This structure makes the conductor appear as a regular cylinder, suitable for 10kV overhead line installation, and can maintain good structural integrity during long-term operation.

[0037] Example 1 provides a heat-resistant aluminum alloy 10KV overhead insulated conductor.

[0038] The conductor adopts a coaxial layered structure, consisting of a conductor, a shielding layer, and an insulation layer from the inside out.

[0039] The conductor is formed by stranding 37 aluminum alloy single wires in a 1+6+12+18 stranding configuration, and then compacted to form a tightly compressed round conductor. The weight percentage composition of the aluminum alloy single wires is: Fe 0.6%, Zr 0.08%, B 0.01%, Si 0.1%, with the remainder being Al and unavoidable impurities. The single wire diameter is φ3.07mm, and the conductor compaction coefficient is 0.92. The shielding layer is located on the outside of the conductor and is formed by spirally wrapping copper wire. The copper wire is continuously wrapped around the outer circumference of the conductor, with adjacent loops forming a continuous covering structure. The insulation layer is located outside the shielding layer and is formed by extrusion of cross-linked polyethylene material, with a thickness of 3.4mm.

[0040] The wire preparation process is as follows: Aluminum alloy raw materials are smelted according to a predetermined ratio, with the smelting temperature controlled between 720℃ and 760℃. After degassing and filtration, the melt is continuously cast and rolled into rods to obtain aluminum alloy rods. A multi-pass wire drawing process is used to draw the aluminum alloy rods into single wires with a diameter of φ3.07mm. The single wires undergo stabilization heat treatment at 260℃ to 320℃ for 2 to 6 hours to eliminate processing stress and stabilize the microstructure. 37 single wires are stranded in a 1+6+12+18 structure and then compressed to form a circular conductor. Copper wire is spirally wrapped around the conductor to form a shielding layer. The conductor is preheated at 100℃ to 120℃ before entering the extruder. Cross-linked polyethylene material is used for the insulation layer extrusion. After the insulation layer extrusion is completed, a cross-linking and shaping treatment is performed to obtain the finished conductor. Example 2

[0041] This embodiment provides a 10KV overhead insulated conductor made of heat-resistant aluminum alloy. The conductor structure is basically the same as in Embodiment 1, consisting of a conductor, a shielding layer, and an insulation layer. The conductor is formed by stranding 37 aluminum alloy single wires in a 1+6+12+18 stranding configuration. The weight percentage composition of the aluminum alloy single wires is: Fe 0.75%, Zr 0.10%, B 0.02%, Si 0.08%, with the remainder being Al and unavoidable impurities. The single wire diameter is φ3.07mm, and the conductor compaction factor is 0.94. The shielding layer is formed by wrapping copper wire. The insulation layer is formed of cross-linked polyethylene material with a thickness of 3.8mm.

[0042] During the preparation process: The melting temperature is controlled at 730℃~750℃; the stabilization heat treatment temperature is controlled at 280℃~340℃; the conductor preheating temperature is controlled at 110℃~120℃; the insulation layer is formed by a double-layer co-extrusion process and then continuously cross-linked and shaped.

[0043] Comparative Example 1 This comparative example provides an overhead insulated conductor. The conductor is formed by stranding 37 single metal wires in a 1+6+12+18 stranding configuration. A cross-linked polyethylene insulation layer is directly extruded onto the outside of the conductor. No shielding layer is provided between the conductor and the insulation layer. The insulation layer thickness is 3.4 mm. The conductor is manufactured using conventional processes, including wire drawing, stranding, insulation extrusion, and cross-linking shaping. Except for the absence of a shielding layer, the other process conditions are consistent with those of Example 1.

[0044] Comparative Example 2 This comparative example provides an overhead insulated conductor. The conductor consists of a conductor, a shielding layer, and an insulation layer. The conductor is formed by stranding 37 single metal wires together in a 1+6+12+18 stranding configuration. The conductor is not compacted. The shielding layer is formed by wrapping copper wire. The insulation layer is formed of cross-linked polyethylene material with a thickness of 3.4 mm. The conductor is manufactured using conventional processes. Except for the conductor not being compacted, the remaining structure and process conditions are consistent with those of Example 1.

[0045] The performance of the samples prepared in Example 1, Example 2, Comparative Example 1 and Comparative Example 2 were tested respectively.

[0046] The test items include: (1) DC resistance at 20℃; (2) Creep elongation at 150℃ for 1000h; (3) Insulation eccentricity; (4) Power frequency breakdown voltage; (5) Insulation retention rate after thermal aging; (6) Current carrying capacity.

[0047] Table 1 Performance test results of each sample Test Result Analysis As can be seen from Table 1, both Example 1 and Example 2 exhibited low creep elongation, indicating that the conductor has good dimensional stability and creep resistance under long-term high-temperature operation conditions.

[0048] Both Example 1 and Example 2 have a shielding layer, and the insulation eccentricity is significantly lower than that of Comparative Example 1, indicating that the shielding layer can improve the uniformity of the outer surface of the conductor, improve the extrusion quality of the insulation layer, and make the thickness distribution of the insulation layer more uniform.

[0049] Both Example 1 and Example 2 employ a compacted circular conductor structure, and their power frequency breakdown voltage is higher than that of Comparative Example 2. This indicates that the compacted conductor is beneficial for improving the uniformity of the insulation layer coverage, reducing local electric field concentration, and improving insulation reliability.

[0050] Example 2 employs a higher compression coefficient and optimized heat treatment process, which further improves the insulation performance retention rate and current carrying capacity after thermal aging, indicating that the conductor has better overall performance under long-term operating conditions.

[0051] Comprehensive test results show that the conductors made of heat-resistant aluminum alloy conductors, compacted circular conductor structure, copper wire wrapped shielding layer and cross-linked polyethylene insulation layer can improve the conductors' heat resistance, creep resistance, insulation reliability and long-term operational stability, and are suitable for 10KV overhead transmission and distribution lines.

[0052] A method for manufacturing a heat-resistant aluminum alloy 10kV overhead insulated conductor, including... S1, Aluminum Alloy Smelting and Rod Making First, the aluminum alloy raw material is melted according to the preset composition. During the melting process, the composition of the melt should be kept as uniform as possible to reduce impurities and oxide inclusions. The melted aluminum alloy is then formed into aluminum alloy rods through continuous casting, rolling, or other conventional rod-making methods. The rods serve as the initial raw material for the subsequent wire drawing process; therefore, the rods need to have a dense structure, a smooth outer surface, and minimize the impact of cracks, holes, and surface oxide layers on subsequent wire drawing.

[0053] S2, Brushed The aluminum alloy rod is fed into a drawing machine for multiple drawing passes, gradually reducing the rod diameter to a single wire. During the drawing process, a continuous, multi-stage diameter reduction method is used to achieve the specified single wire diameter of φ3.07mm. The purpose of using a multi-pass drawing process is to avoid excessive deformation in a single pass, which could lead to stress concentration, surface roughness, or edge tearing within the single wire. It also ensures a more stable single wire diameter and a smoother surface. The surface quality of the single wire directly affects the subsequent conductor stranding quality, shielding layer wrapping quality, and insulation layer extrusion quality. Therefore, the drawing process should strive to ensure that the single wire surface is free of obvious burrs, scratches, and indentations.

[0054] S3, Heat Treatment The drawn single wire undergoes a stabilizing heat treatment. This heat treatment includes stress relief. After heat treatment, the single wire is less prone to significant springback during stranding and compaction, making it easier to form a structurally stable compacted round conductor.

[0055] S4, Tightening Thirty-seven processed single wires are twisted together in a 1+6+12+18 structure to form a four-layer circular conductor. During twisting, the single wires are arranged spirally around the conductor axis, with each layer of single wires successively wrapping around the other, forming a multi-strand conductor structure with a certain degree of flexibility. After twisting, the conductor is compacted, transforming the conductor cross-section from a loosely twisted state to a tightly compressed circular state. After compaction, the outer contour of the conductor becomes more regular, the cross-sectional gaps are significantly reduced, and the surface smoothness of the conductor is improved, facilitating continuous subsequent processes.

[0056] The stranding and compaction process also improves the contact state between individual wires inside the conductor, enhances stability during current carrying, and makes the overall outer diameter of the conductor more uniform. The circular shape formed after compaction makes it easier to match the forming dies for subsequent shielding layer wrapping and insulation layer extrusion, thereby improving the consistency of the finished product.

[0057] S5, Shielding layer configuration A shielding layer is formed by wrapping a metal wire around the outside of the conductor. Copper wire is preferably used for the shielding layer, and it is continuously wrapped around the outer circumference of the conductor in a spiral manner. During the wrapping process, the copper wire moves at a constant speed along the conductor's axis while rotating around the conductor's outer circumference, thus forming a continuously extending axially. The wrapped shielding layer adheres tightly to the outer circumference of the conductor and maintains a certain degree of uniform coverage.

[0058] The wrapping process allows the shielding layer to follow the conductor's outer contour well, preventing tiny protrusions between the conductor's filaments from being directly exposed and affecting the insulation layer's coverage. By controlling the wrapping tension, wrapping angle, and wrapping pitch, a stable, continuous, and regularly shaped intermediate layer structure can be formed around the conductor's periphery. This intermediate layer structure facilitates the continuous extrusion of the subsequent insulation layer, reducing localized unevenness in insulation thickness.

[0059] After the shielding layer is wrapped, a coaxial intermediate layer structure suitable for extrusion is formed on the outer periphery of the conductor, and then the insulation layer extrusion process begins.

[0060] S6, Insulation layer extrusion A cross-linked polyethylene insulation layer 3 is extruded onto the outside of the shielding layer 2. Before extrusion, the conductor 1 is preheated at 100℃-120℃ to raise its surface temperature to a suitable level for extrusion molding, thereby reducing bubbles, delamination, or uneven thickness caused by temperature differences during extrusion. Subsequently, the cross-linked polyethylene material is melted and plasticized in an extruder, then uniformly extruded from the mold and coated onto the outer periphery of the shielding layer to form a continuous insulation layer. After the insulation layer extrusion is completed, the conductor undergoes further cross-linking and shaping treatment to form a stable cross-linked structure inside the insulation layer. The cross-linked and shaped insulation layer has better heat resistance and electrical insulation stability, and can better withstand temperature changes, ultraviolet radiation, and external environmental influences in overhead operation environments.

[0061] The conductor produced through the above steps has a three-layer structure from the inside out: conductor 1, shielding layer 2, and insulation layer 3. Conductor 1 serves as the conductive body, shielding layer 2 serves as the outer perimeter covering of the conductor, and insulation layer 3 serves as the outermost insulating protective layer. Together, these three layers form a heat-resistant aluminum alloy insulated conductor suitable for 10kV overhead lines. This conductor maintains good structural stability and interlayer bonding during long-term overhead use, meeting the continuous operation requirements of power transmission and distribution scenarios.

[0062] In step S2, a multi-pass wire drawing process is used to form a single line with a smooth surface.

[0063] Step S3 includes stress relief treatment.

[0064] The stress-relief heat treatment temperature is 260℃~340℃, and the holding time is 2h~8h. The stress-relief heat treatment eliminates the residual stress formed during the wire drawing process, stabilizes the internal structure of the single wire, reduces springback during subsequent stranding and compaction, and improves the consistency of conductor forming.

[0065] In step S6, the conductor is preheated at 100℃-120℃ before extrusion.

[0066] The preheating process in step S6 is completed using a conductor preheating device. This device is located between the shielding layer wrapping station and the insulation layer extrusion station, connected sequentially along the conductor's running direction. The device includes a preheating chamber, a heating assembly, and a guiding assembly. The preheating chamber has a cylindrical structure, and the semi-finished conductor formed by conductor 1 and shielding layer 2 passes through its center. The heating assembly is located on the inner or outer wall of the preheating chamber to heat the passing conductor. The guiding assembly is located at both ends of the preheating chamber to maintain a stable conductor trajectory. Raising the temperature of conductor 1 and shielding layer 2 to 100℃~120℃ using the conductor preheating device improves the bonding quality between the subsequent insulation layer 3 and shielding layer 2.

[0067] In another embodiment, the insulation layer 3 is formed using a double-layer co-extrusion structure. The double-layer co-extrusion structure includes an inner insulation layer and an outer insulation layer, both made of cross-linked polyethylene material. The inner insulation layer is formed by extrusion using a first extruder, and the outer insulation layer is simultaneously formed by extrusion using a second extruder. Both layers simultaneously coat the outer periphery of the shielding layer 2 within the co-extrusion die. The inner insulation layer is in direct contact with the shielding layer 2, and the outer insulation layer is located outside the inner insulation layer. After the double-layer co-extrusion is formed, a cross-linking and shaping treatment is performed, allowing the two insulation layers to form a continuous, integrated insulation system. The double-layer co-extrusion structure is beneficial for improving the uniformity of the insulation layer thickness distribution and the overall molding stability.

[0068] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention, all of which fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A heat-resistant aluminum alloy 10kV overhead insulated conductor, characterized in that: It includes a conductor, a shielding layer, and an insulating layer, wherein the shielding layer is disposed on the outside of the conductor, and the insulating layer is disposed on the outside of the shielding layer; The conductor is a compacted circular conductor formed by stranding aluminum alloy single wires. The conductor is composed of 37 stranded single wires with a stranding structure of 1+6+12+18. The shielding layer is formed by wrapping metal wires and is disposed on the outside of the conductor by wrapping. The insulating layer is made of cross-linked polyethylene material and is extruded onto the outside of the shielding layer.

2. The heat-resistant aluminum alloy 10kV overhead insulated conductor according to claim 1, characterized in that: The aluminum alloy single wire has the following composition by weight percentage: Fe 0.60%~0.80%, Zr 0.08%~0.12%, B 0.01%~0.03%, Si≤0.10%, and the remainder is Al.

3. The heat-resistant aluminum alloy 10kV overhead insulated conductor according to claim 1, characterized in that: The conductor has a single wire diameter of φ3.07mm and a compaction coefficient of not less than 0.

92.

4. The heat-resistant aluminum alloy 10kV overhead insulated conductor according to claim 1, characterized in that: The shielding layer is formed by wrapping copper wire.

5. The heat-resistant aluminum alloy 10kV overhead insulated conductor according to claim 1, characterized in that: The insulation layer is a cross-linked polyethylene insulation layer, and the thickness of the insulation layer is not less than 3.4 mm.

6. A method for manufacturing a 10kV overhead insulated conductor made of heat-resistant aluminum alloy, characterized in that: For manufacturing a heat-resistant aluminum alloy 10kV overhead insulated conductor as described in any one of claims 1-5, comprising: S1. Aluminum alloy smelting and rod making: Smelting aluminum alloys according to preset compositions and making aluminum alloy rods; S2. Wire drawing: Drawing the aluminum alloy rod into a single wire; S3. Heat treatment: Stabilize the single wire with heat treatment; S4. Stranding and compaction: The 37 single wires are stranded and compacted in a 1+6+12+18 structure to form a circular conductor; S5. Shielding layer configuration: A shielding layer is formed by wrapping metal wire around the outside of the conductor; S6. Extrusion of insulation layer: Extruding a cross-linked polyethylene insulation layer on the outside of the shielding layer and performing cross-linking shaping treatment.

7. The method for manufacturing a 10kV heat-resistant aluminum alloy overhead insulated conductor according to claim 6, characterized in that: In step S2, a multi-pass wire drawing process is used to form a single line with a smooth surface.

8. The method for manufacturing a 10kV overhead insulated conductor of heat-resistant aluminum alloy according to claim 6, characterized in that: Step S3 includes stress relief treatment.

9. The method for manufacturing a 10kV overhead insulated conductor of heat-resistant aluminum alloy according to claim 6, characterized in that: In step S6, the conductor is preheated at 100℃-120℃ before extrusion.

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