Highly conductive aluminum conductor overhead cable

Abstract

The application relates to the technical field of power cable manufacturing, in particular to a high-conductivity aluminum conductor overhead insulated cable which comprises, from inside to outside, a conductor, filling, an inner shielding layer, a main insulation layer and an outer shielding layer; the conductor is made of high-conductivity rare earth aluminum alloy; the inner shielding layer, the main insulation layer and the outer shielding layer are integrally formed through a three-layer co-extrusion process, so that the electrical performance and mechanical performance are stable and reliable. The application has the following advantages: first, the conductivity is improved through the rare earth and trace zirconium composite, while the strength and creep resistance are ensured; second, continuous extrusion and online heat treatment are adopted to realize grain refinement, and high conductivity and high mechanical performance are considered; third, the semi-conductive shielding and weather-resistant XLPE are resistant to ultraviolet rays, aging, high and low temperatures; fourth, the three-layer co-extrusion tight-pressing structure effectively reduces the outer diameter and improves the laying adaptability; and fifth, the high-conductivity aluminum is used to replace copper, and is suitable for large-scale overhead use.

Description

Technical Field

[0001] This invention relates to the field of power cable manufacturing technology, and in particular to a high-conductivity aluminum conductor overhead insulated cable. Background Technology

[0002] my country's power distribution network is undergoing iterative upgrades towards energy conservation, intelligence, and long lifespan. As the core carrier of power transmission in the distribution network, overhead cables directly determine the safety, stability, and energy consumption level of the power grid operation due to their conductivity, insulation reliability, environmental adaptability, and service life. Traditional overhead cable products and related technologies are no longer adequate to meet the development needs of the power distribution network.

[0003] Currently, the main types of products used in China's power distribution network overhead lines are three types, all of which have significant performance shortcomings: First, traditional steel-cored aluminum stranded wire, which lacks insulation protection structure, is prone to problems such as phase-to-phase short circuits, lightning strikes causing line breaks, and tree-induced discharges under severe weather conditions and complex operating conditions, posing significant safety hazards; second, ordinary aluminum conductor overhead insulated cables, which have improved safety after adding an insulation layer, but have low conductor conductivity, high line transmission losses, and insufficient weather resistance of the insulation layer, making them prone to aging and failure after long-term outdoor use; third, copper core insulated cables, which have excellent conductivity, but have high raw material costs and are heavy, significantly increasing the investment in line construction and the load-bearing capacity of towers, thus limiting their large-scale promotion and application.

[0004] Overall, the traditional overhead insulated cable industry suffers from several common technical defects. Firstly, its conductivity is insufficient. Conventional electrical aluminum conductors have a conductivity of only about 59% IACS, leading to significant energy losses in long-distance, high-capacity transmission scenarios. In 10kV distribution networks, line losses account for over 30% of total losses, increasing grid operating costs and failing to meet energy conservation and loss reduction requirements. Secondly, its insulation has poor weather resistance. The industry commonly uses ordinary PE and PVC insulation materials, which have poor resistance to ultraviolet radiation, high and low temperatures, and thermo-oxidative aging. After 3 to 5 years of outdoor use, cracking and embrittlement occur, with insulation performance continuously deteriorating, resulting in an overall service life of less than 15 years. Aging is accelerated in high-UV, salt-spray, and extremely cold regions, leading to high maintenance costs and significant power supply safety risks. Thirdly, there are inherent contradictions in material properties. Traditional aluminum alloys improve mechanical strength by adding alloying elements, but this severely hinders electron transmission and reduces conductivity. Pure aluminum conductors, while possessing excellent conductivity, suffer from low tensile strength, poor creep resistance, and susceptibility to breakage and deformation, making it difficult to simultaneously meet the demands for high conductivity, high strength, and high stability. Fourth, the production process has defects. Traditional continuous casting and rolling processes are prone to problems such as porosity, inclusions, and coarse grains inside the conductor, affecting the conductor's conductivity uniformity and the stability of line operation. Fifth, the structural design is outdated. Traditional cables have a large outer diameter, high wind resistance coefficient, and poor bending performance, which not only makes construction difficult but also places higher demands on the load-bearing capacity of the towers. They also lack adaptability and cannot meet the needs of use in all climate regions, such as high-altitude cold regions, high-temperature regions, coastal salt spray, and high-altitude areas with strong ultraviolet radiation.

[0005] In summary, current overhead cables on the market generally suffer from numerous problems, including high transmission loss, poor insulation and weather resistance, an inability to balance mechanical and conductive properties, weak environmental adaptability, short service life, and high operation and maintenance costs. Existing technologies are ill-suited to the comprehensive requirements of new power system construction for cables with high conductivity, low loss, weather resistance, lightweight, low cost, and long lifespan. Therefore, there is an urgent need to develop a new type of overhead insulated cable with balanced performance that overcomes the shortcomings of traditional technologies. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art, solve the problems mentioned in the background art, and provide a high-conductivity aluminum conductor overhead insulated cable.

[0007] The objective of this invention is achieved through the following technical solution: a high-conductivity aluminum conductor overhead insulated cable, comprising, from the inside out, a conductor, a filler, an inner shielding layer, a main insulation layer, and an outer shielding layer. The conductor is made of a high-conductivity rare-earth aluminum alloy. The inner shielding layer, the main insulation layer, and the outer shielding layer are integrally formed. Through the three-layer integral forming, the electrical and mechanical properties are ensured to be stable and reliable.

[0008] Furthermore, the conductor is made of Al–RE–Zr–Fe series high-conductivity rare earth aluminum alloy, and a balance between conductivity and mechanical properties is achieved through precise composition control.

[0009] Furthermore, the specific composition of the conductor is as follows: aluminum matrix ≥99.6%, rare earth elements (La+Ce) 0.05%–0.15%, zirconium element 0.02%–0.08%, iron ≤0.12%, silicon ≤0.08%, and other impurities total ≤0.08%.

[0010] Furthermore, the conductor adopts a multi-strand layered tightly bonded structure.

[0011] Furthermore, the diameter of the conductor's single filament is controlled between 1.5 and 3.0 mm, the twisting pitch ratio is 10 to 14 times, and the compression coefficient is ≥0.92.

[0012] Furthermore, the conductor is prepared using an integrated process of continuous extrusion and online solution aging.

[0013] Furthermore, the inner shielding layer, the main insulation layer, and the outer shielding layer are manufactured using a three-layer co-extrusion molding process, in which the three layers of material are extruded in one go at the same die head.

[0014] Furthermore, the inner shielding layer is made of semi-conductive HDPE material with a thickness of 0.4–0.8 mm.

[0015] Furthermore, the main insulation layer is made of weather-resistant black XLPE material, with added UV stabilizers, antioxidants, and carbon black stabilizers, and has a thickness of 1.2–2.5 mm.

[0016] Furthermore, the outer shielding layer is made of a semi-conductive material.

[0017] The beneficial effects of this invention are as follows: First, by combining rare earth elements with trace amounts of zirconium, the conductivity is increased to 61.5%–63% IACS, while ensuring strength and creep resistance. Second, continuous extrusion and online heat treatment are used to achieve grain refinement, balancing high conductivity and high mechanical properties. Third, the semi-conductive shielding and weather-resistant XLPE are resistant to ultraviolet rays, aging, and high and low temperatures, significantly extending outdoor lifespan. Fourth, the three-layer co-extrusion compaction structure effectively reduces the outer diameter, improves laying adaptability, and reduces the risk of conductor oxidation and insulation failure. Fifth, by replacing copper with highly conductive aluminum, the weight is reduced by more than 30%, and the cost is reduced by more than 40%, making it suitable for large-scale overhead applications. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is the front view of the present invention.

[0020] In the diagram: 1. Conductor; 2. Filler; 3. Inner shielding layer; 4. Main insulation layer; 5. Outer shielding layer. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Additional aspects and advantages of the invention will be further set forth in the description which follows in conjunction with the accompanying drawings, and in part will be obvious from the description or may be learned by practice of the invention.

[0023] The present invention provides a high-conductivity aluminum conductor overhead insulated cable, such as... Figure 1 and Figure 2As shown, from the inside out, it includes conductor 1, filler 2, inner shielding layer 3, main insulation layer 4 and outer shielding layer 5. Conductor 1 is made of high conductivity rare earth aluminum alloy. Inner shielding layer 3, main insulation layer 4 and outer shielding layer 5 are integrally formed through a three-layer co-extrusion process to ensure stable and reliable electrical and mechanical performance.

[0024] Conductor 1 utilizes a self-developed Al–RE–Zr–Fe series high-conductivity rare-earth aluminum alloy. A balance between conductivity and mechanical properties is achieved through precise composition control. The specific composition of Conductor 1 is: aluminum matrix ≥99.6%, rare earth elements (La+Ce) 0.05%–0.15%, zirconium 0.02%–0.08%, iron ≤0.12%, silicon ≤0.08%, and other impurities ≤0.08%. Rare earth elements purify grain boundaries, refine grains, and reduce lattice defects, while zirconium significantly improves creep resistance and thermal stability, greatly enhancing the mechanical strength of Conductor 1 without sacrificing conductivity. This formula breaks through the performance bottlenecks of traditional aluminum alloys, achieving a conductivity ≥61.5% IACS and a tensile strength ≥160MPa.

[0025] Conductor 1 adopts a multi-strand layered compacted stranding structure. The diameter of a single wire in conductor 1 is controlled between 1.5 and 3.0 mm, the stranding pitch ratio is 10 to 14 times, the compaction coefficient is ≥0.92, and the cross-section of conductor 1 covers 10 mm. 2 -400mm 2 The full range of specifications can meet the requirements of different voltage levels and transmission capacities. The compact stranding process effectively reduces the outer diameter of conductor 1, lowers the wind resistance coefficient, and improves structural stability. At the same time, it reduces the contact area between conductor 1 and air, delaying surface oxidation. Layered stranding can improve cable flexibility and facilitate bending and laying.

[0026] Conductor 1 is prepared using an integrated continuous extrusion and online solution aging process, with precise quality control throughout. The first step is vacuum melting, where impurities and gases are removed from the melt through degassing and online filtration, reducing internal defects. The second step is continuous extrusion, utilizing high-temperature, high-plastic deformation to refine the grains to below 10 μm, improving microstructure uniformity. The third step is online heat treatment, where solution and aging processes regulate the grain structure, balancing conductivity and mechanical strength. Finally, high-precision die drawing and layered stranding ensure the conductor 1 has accurate dimensions and stable performance. This process replaces traditional continuous casting and rolling, effectively eliminating defects such as porosity and inclusions, and improving the consistency of conductor 1.

[0027] The inner shielding layer 3, the main insulation layer 4, and the outer shielding layer 5 are manufactured using a high-pressure three-layer co-extrusion process, extruding the three layers in one go at the same die head to achieve a gapless bond between the layers. During production, the extrusion temperature, traction speed, and crosslinking parameters are precisely controlled to ensure that the insulation layer has a crosslinking degree of ≥75%, free of bubbles, scorching, and interface defects. The crosslinking process uses silane crosslinking, which is simple to operate, low in cost, and produces uniform crosslinking, making it suitable for large-scale industrial production.

[0028] The inner shielding layer 3 is made of semi-conductive HDPE material with a thickness of 0.4–0.8 mm. It can effectively uniformize the electric field, eliminate the air gap between conductor 1 and the insulation layer, and suppress partial discharge. The main insulation layer 4 is made of weather-resistant black XLPE material with added UV inhibitors, antioxidants, and carbon black stabilizers. It has a thickness of 1.2–2.5 mm and has excellent heat resistance, UV resistance, and anti-aging properties. The outer shielding layer 5 is made of semi-conductive material, which facilitates on-site grounding and partial discharge detection, and improves operational safety. The three layers work together to achieve integrated electrical insulation, uniform electric field, and weather protection.

[0029] In summary, this product is widely applicable to various outdoor overhead power transmission and distribution projects, including urban 10kV distribution networks, rural low-voltage overhead lines, industrial park power supply systems, mountain transmission lines, coastal salt spray areas, high-altitude cold areas, and high-UV areas. It can completely replace traditional steel-cored aluminum stranded wire and ordinary overhead insulated cables, and is especially suitable for key projects with high requirements for energy saving, lifespan, and environmental adaptability. Rated voltage: 0.6 / 1kV, 10kV; Conductor 1 conductivity: 61.5%–63% IACS; Long-term operating temperature: -40℃~90℃; Short-circuit withstand temperature: 250℃ / 5s; Power frequency withstand voltage: 3.5kV / 5min without breakdown; Partial discharge: ≤10pC; Insulation resistance: ≥1000MΩ・km; Thermal elongation: ≤175%; Outdoor design service life: ≥25 years.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-conductivity aluminum conductor overhead insulated cable, comprising, from the inside out, a conductor (1), a filler (2), an inner shielding layer (3), a main insulation layer (4), and an outer shielding layer (5), characterized in that: The conductor (1) is made of high-conductivity rare-earth aluminum alloy. The inner shielding layer (3), the main insulation layer (4) and the outer shielding layer (5) are integrally formed. Through the three-layer integral forming, the electrical and mechanical properties are stable and reliable.

2. The high-conductivity aluminum conductor overhead insulated cable according to claim 1, characterized in that: The conductor (1) is made of Al–RE–Zr–Fe series high conductivity rare earth aluminum alloy, and the balance between conductivity and mechanical properties is achieved through precise composition control.

3. The high-conductivity aluminum conductor overhead insulated cable according to claim 2, characterized in that: The specific composition of the conductor (1) is as follows: aluminum matrix ≥99.6%, rare earth elements (La+Ce) 0.05%–0.15%, zirconium element 0.02%–0.08%, iron ≤0.12%, silicon ≤0.08%, and other impurities ≤0.08%.

4. The high-conductivity aluminum conductor overhead insulated cable according to claim 3, characterized in that: The conductor (1) adopts a multi-strand layered tight-stranded structure.

5. The high-conductivity aluminum conductor overhead insulated cable according to claim 4, characterized in that: The diameter of the single filament of the conductor (1) is controlled at 1.5–3.0 mm, the twisting pitch ratio is 10–14 times, and the compression coefficient is ≥0.

92.

6. The high-conductivity aluminum conductor overhead insulated cable according to claim 5, characterized in that: The conductor (1) is prepared by a continuous extrusion and online solution aging integrated process.

7. The high-conductivity aluminum conductor overhead insulated cable according to claim 1, characterized in that: The inner shielding layer (3), the main insulation layer (4) and the outer shielding layer (5) are formed by a three-layer co-extrusion molding process, in which the three layers of materials are extruded at the same die head in one go.

8. The high-conductivity aluminum conductor overhead insulated cable according to claim 7, characterized in that: The inner shielding layer (3) is made of semi-conductive HDPE material with a thickness of 0.4–0.8 mm.

9. The high-conductivity aluminum conductor overhead insulated cable according to claim 7, characterized in that: The main insulation layer (4) is made of weather-resistant black XLPE material with added UV stabilizer, antioxidant and carbon black stabilizer, and has a thickness of 1.2–2.5 mm.

10. The high-conductivity aluminum conductor overhead insulated cable according to claim 7, characterized in that: The outer shielding layer (5) is made of a semi-conductive material.

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