High strength steel cored aluminium alloy strand for power grids

Abstract

This invention relates to the field of aluminum alloy stranded wire technology and discloses a high-strength steel-cored aluminum alloy stranded wire for power grids, comprising a cladding layer; aluminum stranded wire, steel stranded wire, and fine stranded wire; and a hollow support device. The hollow support device includes an outer helical spring and an inner helical spring, with the aluminum stranded wire, steel stranded wire, and fine stranded wire all located in the gap between the outer and inner helical springs. This high-strength steel-cored aluminum alloy stranded wire for power grids, through the hollow support device, can convert the entire stranded wire structure into a hollow structure, reducing weight and thus reducing the load on the tower, thereby lowering the material and construction costs of the support structure. The hollow conductor can significantly improve the overall bending stiffness and stability with only a slight increase in weight, resulting in a higher strength-to-weight ratio. The hollow portion can be circulated with inert gas or low-viscosity coolant to achieve active cooling of the conductor, thereby significantly increasing the conductor's current carrying capacity.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy stranded wire technology, specifically a high-strength steel-cored aluminum alloy stranded wire for use in power grids. Background Technology

[0002] With the rapid growth of electricity demand in my country, the requirements for power transmission are also becoming increasingly stringent. my country is a country with numerous rivers, lakes, mountains, and valleys. Especially with the development of the western regions, the transmission of hydropower and thermal power from the northwest and southwest to the more developed central and eastern regions necessitates high-voltage transmission lines crossing various sections, making the demand for high-capacity, long-span conductors with special performance essential. However, currently, the conductors used in my country's overhead transmission lines are still primarily traditional steel-cored aluminum stranded wire, which has relatively weak heat resistance and corrosion resistance, thus limiting the transmission capacity and service life of the lines.

[0003] Current aluminum alloy stranded wires are quite heavy due to the internal aluminum strand filling, which limits their transportation and use. Furthermore, since these wires are suspended in high-altitude power grids, their weight results in significant sag, and the tension clamps at both ends directly bear the entire weight. Additionally, the heat generated by the large current flow within these wires cannot be effectively dissipated and is typically absorbed by the outer sheath, easily leading to softening of the sheath and reduced lifespan. Therefore, a high-strength steel-cored aluminum alloy stranded wire for power grids is proposed to address these issues. Summary of the Invention

[0004] Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a high-strength steel-cored aluminum alloy stranded wire for power grids, which solves the problems of heavy weight, poor internal heat dissipation, and short service life of existing aluminum alloy stranded wires.

[0005] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: A high-strength steel-cored aluminum alloy stranded wire for power grids includes: a cladding layer; aluminum stranded wire, steel stranded wire, and fine stranded wire; a hollow support device; the hollow support device includes an outer helical spring and an inner helical spring, the aluminum stranded wire, steel stranded wire, and fine stranded wire are all located in the gap between the outer helical spring and the inner helical spring, a steel core wire is disposed inside the inner helical spring, the outer helical spring is connected to the cladding layer, the steel stranded wire abuts against the outer surface of the inner helical spring, and the interior of the inner helical spring has a hollow structure, forming a hollow airflow channel.

[0006] Preferably, both the outer and inner helical springs are elastic springs, and the inner helical spring consists of two rigid springs arranged alternately, with the two ends of the two rigid springs connected in series by a connector. A support frame is provided between the steel strand and the fine strand to provide elastic support between the steel strand and the fine strand.

[0007] Preferably, the support frame includes a first ring and a second ring, with an S-shaped elastic piece connecting the first ring and the second ring. The elastic piece is provided with a top piece, and the first ring and the second ring are sleeved on the outer surface of the steel strand.

[0008] Preferably, there are four sets of elastic sheets and top sheets, and the four sets of elastic sheets and top sheets divide the circular space into four regions, with the fine twisted wire filling the four regions.

[0009] Preferably, both the outer and inner helical springs have gaps on their rigid springs. Multiple sets of inner helical springs are provided, and each set of inner helical springs has connecting pieces at both ends. Each set of inner helical springs is connected in series with each other through two connecting pieces.

[0010] Preferably, the two connecting pieces are respectively provided with a slot and a key, and the key on one connecting piece and the slot on the other connecting piece cooperate to engage.

[0011] Preferably, the aluminum stranded wire is composed of multiple aluminum alloy wires, and the multiple aluminum stranded wires are spirally wound on the outer surface of multiple sets of fine stranded wires 7.

[0012] Preferably, it further includes a heat dissipation component, which includes an arc sleeve disposed on the outer surface of the covering layer. An inner ring is disposed inside the covering layer. The gap between the inner ring and the arc sleeve forms a receiving cavity. An air hole is opened on the inner ring. A heat-conducting plate is disposed on the inner ring. The heat-conducting plate is fixedly connected to the arc sleeve, and the surface of the heat-conducting plate is exposed on the outer surface of the arc sleeve.

[0013] Preferably, the heat dissipation element is provided in multiple sets, and the multiple sets of heat dissipation elements are arranged in a linear array on the surface of the coating layer. The two sets of connecting pieces are provided with slots, and the lateral displacement difference between the multiple heat dissipation elements and the multiple connecting pieces is <25mm.

[0014] (III) Beneficial Effects Compared with the prior art, the present invention provides a high-strength steel-cored aluminum alloy stranded wire for power grids, which has the following beneficial effects: 1. This high-strength steel-cored aluminum alloy stranded wire for power grids, through the installation of a hollow support device, can transform the entire stranded wire structure into a hollow structure. The most direct advantage of the hollow structure is weight reduction, which can be effectively applied to ultra-high voltage and long-span transmission lines (such as those crossing rivers and canyons). The reduced conductor weight can decrease the load on the towers, thereby reducing the material and construction costs of the support structure. The hollow conductor can significantly improve the overall bending stiffness and stability with only a slight increase in weight, thus achieving a higher strength-to-weight ratio. The hollow part can be circulated with inert gas or low-viscosity coolant to achieve active cooling of the conductor, thereby greatly increasing the conductor's current carrying capacity.

[0015] 2. This high-strength steel-cored aluminum alloy stranded wire for power grids, through the inclusion of heat dissipation components, enables the dissipation of heat. The heat generated by the stranded wire gradually flows into the containment cavity, and then, through thermal conduction, radiates the heat onto the heat-conducting plates. The heat-conducting plates then radiate their own heat to the outside. Without compromising the sealing effect, the internal heat of the stranded wire is dissipated through thermal radiation and conduction, improving the overall operational stability and service life of the stranded wire. This also prevents heat from accumulating inside the coating layer, causing thermal expansion and damage to the coating layer. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a high-strength steel-cored aluminum alloy stranded wire for power grids proposed in this invention. Figure 2 This is a schematic diagram of the connection structure between the cladding layer and the outer helical spring of a high-strength steel-cored aluminum alloy stranded wire for power grids proposed in this invention. Figure 3 This is a schematic diagram of the aluminum stranded wire structure of a high-strength steel-cored aluminum alloy stranded wire for power grids proposed in this invention. Figure 4 This is a schematic diagram of the inner helical spring structure of a high-strength steel-cored aluminum alloy stranded wire for power grids proposed in this invention. Figure 5 This is a schematic diagram of a support frame structure for a high-strength steel-cored aluminum alloy stranded wire used in power grids, as proposed in this invention. Figure 6 This is a schematic diagram of a heat dissipation component for a high-strength steel-cored aluminum alloy stranded wire used in power grids, as proposed in this invention.

[0017] In the diagram: 1. Covering layer; 2. Outer helical spring; 3. Aluminum stranded wire; 4. Steel stranded wire; 5. Inner helical spring; 6. Steel core wire; 7. Fine stranded wire; 8. Support frame; 801. Top plate; 802. Ring one; 803. Elastic sheet; 804. Ring two; 9. Heat dissipation component; 901. Arc sleeve; 902. Vent; 903. Inner ring; 904. Heat-conducting plate; 905. Receiving cavity; 10. Connecting plate. Detailed Implementation

[0018] 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.

[0019] Please see Figures 1-6A high-strength steel-cored aluminum alloy stranded wire for power grids includes a sheathing layer 1. The sheathing layer 1, serving as the first layer of protection for the stranded wire, is typically made of a polymer material with excellent weather resistance, providing insulation, corrosion resistance, and UV protection. It also includes aluminum stranded wires 3, steel stranded wires 4, and fine stranded wires 7; and a hollow support device. The hollow support device includes an outer helical spring 2 and an inner helical spring 5. The aluminum stranded wires 3, steel stranded wires 4, and fine stranded wires 7 are all located in the gap between the outer helical spring 2 and the inner helical spring 5. A steel core wire 6 is installed inside the inner helical spring 5. The outer helical spring 2 is connected to the sheathing layer 1, and the steel stranded wires 4 abut against the outer surface of the inner helical spring 5. The inner helical spring 5 has a hollow structure, forming an airflow channel. The entire central structure is not constructed using a hollow tube, but rather a collaborative support system composed of the outer helical spring 2 and the inner helical spring 5. Within this annular gap constructed by the helical springs, the aluminum stranded wires 3, steel stranded wires 4, and fine stranded wires 7 are arranged and compressed for fixation. Both helical springs are made of highly elastic, high-strength materials such as special spring steel. They act like a "steel skeleton" in a building, collectively defining an annular gap space between the two. The aluminum stranded wire 3 serves as the primary conductor, undertaking most of the current transmission. The steel stranded wire 4 directly abuts against the outer surface of the inner helical spring 5, primarily responsible for bearing most of the tension of the stranded wire. Its tight connection with the inner helical spring 5 greatly enhances the overall tensile strength. The fine stranded wire 7 fills the gap, playing a role in assisting conductivity, optimizing the cross-sectional filling rate, and stabilizing the overall structure. The interior of the inner helical spring 5 is not completely empty; instead, a steel core wire 6 is installed. This steel core wire 6 is the ultimate guarantee of the stranded wire's tensile strength, forming a "rigid yet flexible" central load-bearing structure together with the inner helical spring 5. Simultaneously, the helical structure of the inner helical spring 5 naturally creates a continuous, mechanically protected airflow channel within it. Considering the flexibility of the stranded wire in power grid applications, an outer helical spring 2 and an inner helical spring 5 are installed to improve the overall bending performance of the stranded wire while simultaneously reducing its weight. The outer helical spring 2, the inner helical spring 5, and the internal steel core wire 6 together form an extremely stable support frame, giving the stranded wire extremely high bending stiffness and stability. At the same time, the hollow design achieves significant weight reduction, resulting in an excellent strength-to-weight ratio. All conductive and reinforcing wires are orderly constrained between the helical spring skeleton, resulting in a compact structure and uniform stress distribution, avoiding the internal stress concentration and loose structure problems that may occur in traditional stranded wires.

[0020] In this embodiment, both the outer helical spring 2 and the inner helical spring 5 are elastic springs. The inner helical spring 5 consists of two rigid springs interleaved, with both ends of the two rigid springs connected in series via connectors. A support frame 8 is provided between the steel strand 4 and the thin strand 7 to provide elastic support between them. Both the outer helical spring 2 and the inner helical spring 5 are designed as spring structures with excellent elasticity. This ensures that the entire support frame is not a rigid body, but a "living" structure capable of elastic deformation within a certain range. This structure allows the stranded wires to absorb and disperse energy through slight deformation when encountering dynamic loads such as strong winds and icing, effectively buffering external impacts and suppressing fatigue damage, thereby significantly improving the adaptability and service life of the line in harsh environments. The inner helical spring 5, supported by two springs, greatly enhances the structure's resistance to radial compression, ensuring that the central airflow channel remains stable and unobstructed under any operating conditions and is not easily crushed by external pressure. The interlaced spirals form a denser support point, allowing the load from the inner steel core 6 and the outer steel strand 4 to be transmitted and dispersed more evenly, thus avoiding localized stress concentration.

[0021] Furthermore, the support frame 8 includes a first ring 802 and a second ring 804, with an S-shaped elastic piece 803 connecting the first ring 802 and the second ring 804. A top piece 801 is provided on the elastic piece 803. The first ring 802 and the second ring 804 are fitted onto the outer surface of the steel strand 4. The support frame 8 prevents wear caused by collisions and friction between different wire bundles during bending, twisting, or vibration of the strand, protecting the surface of the wire. Part of the load borne by the thin strand 7 is more gently transferred to the steel strand 4, the main load-bearing component, through the elastic medium of the support frame 8, achieving a "soft connection" between different wire bundles. Through multiple support frames 8 distributed throughout the interior, the previously relatively independent wire bundles are connected into a tightly integrated community, jointly resisting deformation and improving the overall structural rigidity and stability of the strand.

[0022] Furthermore, four sets of elastic plates 803 and top plates 801 are provided, dividing the circular space into four regions, with the fine stranded wire 7 filling and set within each region. On the support frame 8, the elastic plates 803 and their top plates 801 together form an independent elastic support unit. Four such units are precisely positioned and evenly and symmetrically distributed along the circumference of the first ring 802 and the second ring 804. The four divided regions are specifically designed to accommodate and fix the fine stranded wire 7. The fine stranded wire 7 is no longer considered a disordered filler, but rather systematically bundled and filled within these four independent regions, reducing the possibility of multiple fine stranded wires 7 being squeezed, misaligned, or rubbed when the entire stranded wire is bent. Constraining the fine stranded wire 7 within a fixed region effectively prevents arbitrary relative movement, friction, and entanglement with the central steel strand 4 or other wire bundles under dynamic loads, greatly reducing internal wear. The four sets of elastic plates 803 act like four springs, applying a moderate, centripetal elastic compressive force to the stranded wires 7 within their respective areas. This not only dampens the vibration of the stranded wires 7 but also ensures that when the strands bend, the wire bundles in the four areas can participate in the stress synchronously and evenly, preventing stress concentration on one side. When the stranded wires are subjected to external compression or bending, the pressure is transmitted to the support frame 8. At this time, the four sets of S-shaped elastic plates 803 can undergo coordinated elastic deformation to absorb energy; while the top plate 801 on top acts as a direct force-bearing surface, transmitting the pressure more evenly to the stranded wire bundle.

[0023] Furthermore, gaps are provided on the rigid springs of both the outer helical spring 2 and the inner helical spring 5. Multiple sets of inner helical springs 5 ​​are provided, and each set has connecting pieces 10 at both ends. Each set of inner helical springs 5 ​​is connected in series via two connecting pieces 10. The gaps on the rigid springs of both the outer helical spring 2 and the inner helical spring 5 are not manufacturing defects, but rather a certain degree of gap in the helical structure of the "spring," meaning they are not completely helically connected. This is because when the outer helical spring 2 and the inner helical spring 5 are in helical contact during subsequent use of the stranded wire, stress concentration can easily occur, leading to a risk of breakage. This connection ensures the continuous flow of air through the internal airflow channel formed by the inner helical spring 5. The connecting pieces 10 are designed with corresponding through holes or flow channels, allowing cooling media such as inert gases or coolants to pass unimpeded through each module, achieving efficient active cooling along the entire length of the stranded wire. Furthermore, if the entire stranded wire length is long, the requirement for producing continuous inner helical springs 5 ​​becomes too high; therefore, multiple inner helical springs 5 ​​are used in series.

[0024] In addition, each of the two connecting pieces 10 has a slot and a key, with the key on one connecting piece 10 engaging with the slot on the other. During connection, the operator simply aligns the key on one end and pushes it into the slot on the other end to achieve quick, precise alignment and mechanical interlocking. This achieves an assembly effect similar to a "quick connector," greatly improving the efficiency of connecting multiple sets of internal helical springs 5 ​​in series during manufacturing or on-site installation. Once the connection is complete, the tight fit between the key and the slot effectively transmits axial tension, pressure, and torque, ensuring the continuity of mechanical properties. This mechanical connection, while achieving structural connection, perfectly maintains the continuity of the airflow channel inside the internal helical spring 5, providing structural protection for the flow of the cooling medium. The aluminum stranded wire 3 is composed of multiple aluminum alloy wires, and these multiple aluminum stranded wires 3 are spirally wound around the outer surface of multiple sets of fine stranded wires 7. These multiple strands of aluminum wire 3, already formed into strands, are not simply placed on the outer layer. Instead, they are tightly and regularly wound in a spiral pattern around the outer surface of the inner core structure, which consists of multiple sets of fine strands 7 and a support frame 8. This spiral winding method integrates the aluminum strands 3 with the internal core structure into a unified whole, forming the outermost robust conductive and protective layer of the stranded wire. The spiral structure helps to balance the skin effect under alternating current, improve current distribution, and reduce alternating current resistance. The spirally wound aluminum strands 3, like a "bandage," exert a centripetal binding force on the inner fine strands 7, steel strands 4, and hollow support device, further consolidating the overall structural stability of the stranded wire and enabling it to better coordinate deformation and stress.

[0025] It is worth noting that a heat dissipation component 9 is also included. The heat dissipation component 9 includes an arc-shaped sleeve 901, which is disposed on the outer surface of the covering layer 1. An inner ring 903 is disposed inside the covering layer 1. The gap between the inner ring 903 and the arc-shaped sleeve 901 forms a receiving cavity 905. Air holes 902 are provided on the inner ring 903, and a heat-conducting plate 904 is disposed on the inner ring 903. The heat-conducting plate 904 is fixedly connected to the arc-shaped sleeve 901, and its surface is exposed on the outer surface of the arc-shaped sleeve 901. Inside the covering layer 1, corresponding to the position of the heat dissipation component 9, an inner ring 903 is embedded. The inner ring 903 is fixedly connected to the outer arc-shaped sleeve 901 by mechanical or adhesive means, and the sealed gap between them forms a hollow, annular receiving cavity 905. This cavity is a vacuum or a sealed cavity filled with a highly efficient heat-conducting medium such as inert gas or thermal grease. Its core function is to construct a highly efficient heat conduction path that isolates convection. The heat generated during stranded wire operation is first transferred from the inner conductor to the cladding layer 1. The vents 902 on the inner ring 903 of the cladding layer 1 are not for ventilation, but rather provide a low thermal resistance window for the radiation and conduction of heat from inside the stranded wire to the receiving cavity 905, allowing heat to accumulate efficiently within the cavity. One end of the heat-conducting plate 904 is connected to the inner ring 903, while the other end passes through and is fixed to the outer arc-shaped sleeve 901, with its surface directly exposed to the air. Thus, the heat-conducting plate 904 constitutes a highly efficient thermal bridge connecting the internal "heat source" receiving cavity 905 with the external "cold source"—ambient air. The heat transferred to the outer surface through the heat-conducting plate 904 is ultimately dissipated into the surrounding environment through two methods.

[0026] It is worth noting that multiple sets of heat dissipation elements 9 are provided, and these multiple sets of heat dissipation elements 9 are arranged in a linear array on the surface of the covering layer 1. The purpose of the array arrangement is to make heat dissipation more uniform, forming a continuous and uniform heat dissipation band along the length of the conductor, avoiding local overheating areas, and allowing heat to be evenly dissipated from multiple points along the entire conductor. The two sets of connecting pieces 10 have slots, and the lateral displacement difference between the multiple heat dissipation elements 9 and the multiple connecting pieces 10 is <25mm. The purpose of the slots is to provide an outlet for the heat accumulated in the hollow channel. The heat accumulated in the hollow position will be discharged from the slots, and then flow from the gaps between the various strands into the interior of the receiving cavity 905 for further heat dissipation, preventing heat from accumulating in the hollow channel for a long time and causing the center temperature to become too high.

[0027] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A high strength steel cored aluminium alloy strand for use in an electrical power grid, characterised in that, include: Covering layer (1); Aluminum stranded wire (3), steel stranded wire (4) and fine stranded wire (7); Hollow support device; The hollow support device includes an outer helical spring (2) and an inner helical spring (5). The aluminum stranded wire (3), steel stranded wire (4) and fine stranded wire (7) are all located in the gap between the outer helical spring (2) and the inner helical spring (5). A steel core wire (6) is provided inside the inner helical spring (5). The outer helical spring (2) is connected to the covering layer (1). The steel stranded wire (4) abuts against the outer surface of the inner helical spring (5). The interior of the inner helical spring (5) has a hollow structure, forming a hollow air flow channel. It also includes a heat dissipation component (9), which includes an arc sleeve (901). The arc sleeve (901) is disposed on the outer surface of the covering layer (1). An inner ring (903) is disposed inside the covering layer (1). A cavity (905) is formed by the gap between the inner ring (903) and the arc sleeve (901). An air hole (902) is opened on the inner ring (903). A heat-conducting plate (904) is disposed on the inner ring (903). The heat-conducting plate (904) is fixedly connected to the arc sleeve (901), and the surface of the heat-conducting plate (904) is exposed on the outer surface of the arc sleeve (901).

2. A high strength steel cored aluminium alloy strand for power grids according to claim 1, characterized in that: Both the outer helical spring (2) and the inner helical spring (5) are springs with elasticity. The inner helical spring (5) is made up of two rigid springs that are staggered. Both ends of the two rigid springs are connected in series by connectors. A support frame (8) is provided between the steel strand (4) and the fine strand (7). The support frame (8) is used to provide elastic support between the steel strand (4) and the fine strand (7).

3. A high strength steel cored aluminium alloy strand for power grids according to claim 2, characterized in that: The support frame (8) includes a first ring (802) and a second ring (804). An S-shaped elastic piece (803) is connected between the first ring (802) and the second ring (804). A top piece (801) is provided on the elastic piece (803). The first ring (802) and the second ring (804) are sleeved on the outer surface of the steel strand (4).

4. A high strength steel cored aluminium alloy strand for power grids according to claim 3, characterized in that: The elastic sheet (803) and top sheet (801) are provided in four sets, and the four sets of elastic sheet (803) and top sheet (801) divide the circular space into four regions, and the fine twisted wire (7) is filled in the four regions.

5. A high strength steel cored aluminium alloy strand for power grids according to claim 1, characterized in that: The rigid springs of the outer helical spring (2) and the inner helical spring (5) are provided with gaps. There are multiple sets of inner helical springs (5), and each set of inner helical springs (5) is provided with connecting pieces (10) at both ends. Each set of inner helical springs (5) is connected in series with each other through two connecting pieces (10).

6. A high strength steel cored aluminium alloy strand for power grids according to claim 5, characterized in that: The two connecting pieces (10) are respectively provided with slots and key, and the key on one connecting piece (10) and the slot on the other connecting piece (10) are engaged with each other.

7. A high strength steel cored aluminium alloy strand for power grids according to claim 1, characterized in that: The aluminum stranded wire (3) is composed of multiple aluminum alloy wires, and the multiple aluminum stranded wires (3) are spirally wound on the outer surface of multiple sets of fine stranded wires (7).

8. A high strength steel cored aluminium alloy strand for power grids according to claim 1, characterized in that: The heat dissipation element (9) is provided in multiple sets, and the multiple sets of heat dissipation elements (9) are arranged in a linear array on the surface of the covering layer (1). The two sets of connecting pieces (10) are provided with slots, and the lateral displacement difference between the multiple heat dissipation elements (9) and the multiple connecting pieces (10) is <25mm.

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