Large span tensile power cable

Abstract

The utility model discloses a kind of large-span tensile electric power cables, including conductor layer and sheath layer sequentially arranged from inside to outside, and reinforcing member is arranged in parallel above conductor layer. Conductor layer is concentrically stranded by multiple hard round metal wires, and can include the composite structure of reinforcing core and outer layer wire. The cross section of sheath layer is symmetrically shaped, the curvature radius of its upper end face is less than lower end face, and conductor layer is below the center of gravity of cable, and reinforcing member is above the center of gravity, using Bernoulli effect to make cable produce "self-suspension" tendency under wind force, effectively reduce sag. Side ears can be symmetrically arranged on both sides of sheath layer to optimize wind resistance. The utility model has reasonable structure, and has high tensile strength, excellent sag characteristics, wind resistance stability and corrosion resistance, especially suitable for large-span power transmission projects such as crossing sea, crossing valley.

Description

Technical Field

[0001] This utility model relates to the field of power transmission equipment technology, specifically to a power cable suitable for long-span, complex environment installation, with high tensile strength and corrosion resistance. Background Technology

[0002] When crossing navigable rivers, straits, lakes, and canyons, power transmission lines often need to be erected with long spans. Such applications place extremely high demands on overhead conductors: they must have ultra-long lengths, extremely high overall tensile strength to withstand enormous weight and tension, excellent sag characteristics to reduce sagging, and strong corrosion resistance to cope with the harsh environment of high salinity and high humidity above water.

[0003] Traditional cable conductor structures often face the following problems when dealing with long spans of several kilometers: first, excessive sag due to their own weight affects navigation safety and increases material costs; second, insufficient tensile strength poses a risk of wire breakage; and third, limited corrosion resistance significantly shortens their lifespan in harsh weather conditions. Therefore, a new type of cable structure that can comprehensively solve these problems is urgently needed. Utility Model Content

[0004] The purpose of this utility model is to overcome the shortcomings of the existing technology and provide a long-span "self-suspended" tensile power cable to solve the technical problems of traditional cables such as large sag, insufficient tensile strength, susceptibility to wind swing and poor corrosion resistance when used in long-span applications.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a long-span tensile power cable, comprising a conductor layer and a sheath layer arranged sequentially from the inside to the outside, and a non-metallic reinforcing member arranged parallel above the conductor layer; the conductor layer is formed by multiple smooth, rigid, circular metal wires concentrically twisted together; the cross-section of the sheath layer is symmetrically shaped like a "Z", with the radius of curvature of its upper end face being less than the radius of curvature of its lower end face; the conductor layer is disposed below the centroid of the cable cross-section, and the reinforcing member is disposed above the centroid of the cable cross-section.

[0006] The aerodynamic design of this cable allows it to generate an upward lift force when exposed to wind, based on Bernoulli's principle. The upper surface of the cable has a faster airflow and lower pressure, while the lower surface has a slower airflow and higher pressure, thus creating a "self-suspending" effect that effectively counteracts its own weight and prevents sagging.

[0007] As a preferred embodiment of the high-flexibility tensile-strength shielded power cable of this utility model, the conductor layer includes a reinforcing core made of multiple high-strength metal wires twisted together and an outer conductor made of multiple highly conductive metal wires twisted together, covering the reinforcing core. This structure significantly improves the overall tensile strength and conductivity of the conductor without significantly increasing the diameter.

[0008] As a preferred embodiment of the highly flexible tensile shielded power cable of the present utility model, an elastic layer is coated on the outside of the non-metallic strengthening member. The strengthening member is arranged parallel above the conductor layer and is made of a non-metallic material with excellent rigidity and elasticity, and is used to support the cable. To further protect the strengthening member and enhance buffering, an elastic layer is coated on its outside.

[0009] As a preferred embodiment of the highly flexible tensile shielded power cable of the present utility model, side ears are symmetrically arranged on both sides of the sheath layer.

[0010] As a preferred embodiment of the highly flexible tensile shielded power cable of the present utility model, the side ear is in a U-shape, and the length of the lower side of the side ear ≤ the length of the upper side of the side ear.

[0011] As a preferred embodiment of the highly flexible tensile shielded power cable of the present utility model, the side ear is triangular, and the length of the lower side of the side ear ≤ the length of the upper side of the side ear.

[0012] As a preferred embodiment of the highly flexible tensile shielded power cable of the present utility model, the height of the connection line of the centers of gravity of the two side ears is above the center of gravity of the cable cross-section.

[0013] To optimize the wind resistance and enhance the "self-suspension" effect, side ears are provided on both sides of the sheath layer. The side ear structure can effectively guide the lateral incoming wind and assist in generating and stabilizing the "self-suspension" lift force.

[0014] As a preferred embodiment of the highly flexible tensile shielded power cable of the present utility model, an anti-corrosion layer is further provided on the outer surface of the sheath layer.

[0015] Compared with the prior art, the present utility model has the following remarkable advantages: (1) High tensile strength: Through the composite conductor structure of "strengthening core + outer layer wire" and the independently arranged strengthening member, they work together to jointly bear the tension, enabling the cable to withstand the huge tension brought by large spans.

[0016] (2) Excellent sag characteristics: Utilizing the unique U-shaped aerodynamic shape and center of gravity distribution of the sheath layer, a "self-suspension" tendency is generated under the action of wind force, effectively reducing the sag caused by self-weight and wind load.

[0017] (3) Good stability: The design of the side ears enhances the stability of the cable under side wind and assists in improving the "self-suspension" effect, reducing wind vibration swing.

[0018] (4) Strong corrosion resistance: The externally provided anti-corrosion layer provides additional protection for the cable and extends the service life in corrosive environments such as humidity and high salt.

[0019] (5) Excellent comprehensive performance: This utility model has a compact structure, integrating high tensile strength, "self-suspending" and corrosion resistance, and is particularly suitable for harsh power transmission scenarios with large spans and heavy corrosion, such as crossing the sea and lake. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the cross-sectional structure of the large-span tensile power cable of this utility model; Figure 2 This is a partially enlarged schematic diagram of one embodiment of the sheath layer and side ears in this utility model; In the diagram: conductor layer 1, reinforcing core 11, outer conductor 12, reinforcing member 2, elastic layer 21, sheath layer 3, side ear 31, anti-corrosion layer 4, center of gravity G, center of gravity connection line H. Detailed Implementation

[0022] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments.

[0025] Example 1: 10km-class long-span cable suitable for cross-sea power transmission like Figure 1 As shown, the core of this utility model is the unique structure and spatial relationship of the conductor layer 1, the reinforcing member 2, and the sheath layer 3.

[0026] The conductor layer adopts a composite stranded structure. The internal strengthening core 11 is composed of 37 zinc-5% aluminum alloy coated steel core wires with a diameter of Ф3.44 mm and a strength grade of G7A. The surface of the wires has a corrosion-resistant coating. The outer conductor 12 is formed by concentrically stranding 54 high-strength aluminum alloy wires with a diameter of Ф3.44 mm around the outside of the strengthening core.

[0027] The aluminum alloy wire is prepared from an aluminum-magnesium-silicon alloy by a specific process. Its chemical composition is controlled by weight percentage as follows: Si: 0.5% - 0.8%; Mg: 0.6% - 0.9%; Re: 0.1% - 0.2%; Fe: 0.13% - 0.25%. The alloy wire is obtained through the following process: The aluminum alloy melt is refined at 730 - 780 °C for not less than 8 minutes, and then left standing for 40 - 50 minutes; then it enters a continuous casting and rolling mill for isothermal rolling to obtain a high-strength aluminum alloy rod; finally, it undergoes continuous aging treatment in an aging furnace to obtain the final product. The high-strength aluminum alloy wire prepared by this process has a conductivity > 52.5% IACS at 20 °C, a tensile strength ≥ 325 MPa, and an elongation rate ≥ 3.0%.

[0028] The stranding of the conductor layer is completed by a basket strander. During the stranding process, constant tension control is maintained, and by adjusting the pre-twisting device and the stress-relieving device, it is ensured that the wires are tightly stranded and do not loosen when cut.

[0029] The strengthening member is arranged parallel to the upper side of the conductor layer and is formed by mixing and stranding multiple glass fiber and aramid fiber, making it have both high rigidity and excellent elasticity. The outside of the strengthening member is coated with an elastic layer 21, which is made of polyurethane material and serves to buffer, resist tension, recover, and wear-resistant.

[0030] The sheath layer is extruded and formed using high-density polyethylene material, and its cross-section is a symmetric inverted U shape. The key point is that the radius of curvature R1 of its upper end face is 8 mm, and the radius of curvature R2 of its lower end face is 15 mm (R1 < R2). Through reasonable density and structure design, the conductor layer is located below the centroid of the entire cable cross-section, while the strengthening member is located above the centroid G. The conductor layer being set below the centroid of the entire cable cross-section helps with the stability of the cable.

[0031] See Figure 2 , on both sides of the sheath layer and above the centroid G, side ears 31 are symmetrically arranged. The cross-section of the side ear is an approximately triangular shape with a wider upper part and a narrower lower part. The length L2 of its lower side is 2 mm, and the length L1 of its upper side is 3 mm (L2 < L1). The centroid connection line H of the two side ears is located above the centroid of the cable cross-section. This structure can optimize the wind field and generate additional guiding lift when there is a lateral incoming wind, enhancing the stability of the "self-suspension" effect.

[0032] On the outer surface of the sheath layer, a 0.2mm thick fluorocarbon coating anti-corrosion layer 4 is applied to address the high salt and high humidity corrosion problem in the marine environment.

[0033] The cable produced in this embodiment can reach a length of 10km and weighs approximately 41 tons. Testing showed that the cable's overall tensile strength exceeds 820kN, meeting the strength requirements for long-span installations. In wind tunnel tests at 15m / s, the cable exhibited a significant "self-suspending" effect, with sag reduced by more than 25% compared to traditional round cables. Accelerated corrosion tests demonstrated that the cable with the anti-corrosion layer has a lifespan more than 30% longer than untreated similar products.

[0034] Example 2: Lightweight, long-span cable suitable for canyon terrain This embodiment has the same core structure as Embodiment 1, the main difference being that the parameters are adapted for lightweight applications.

[0035] Conductor layer: The reinforcing core uses 19 high-strength anti-corrosion steel wires with a diameter of 2.5mm, and the outer conductor uses 37 high-strength aluminum alloy wires with a diameter of 2.5mm.

[0036] Reinforcing components: Made of pure aramid fiber bundles with reduced diameter while maintaining high tensile strength.

[0037] Sheath layer: Made of medium-density polyethylene, the overall cable weight is reduced by about 30%, making it suitable for crossing canyon terrain where weight is more critical.

[0038] As can be seen from the above embodiments, this utility model, through specific structural design and detailed process implementation, can produce high-performance cables suitable for different long-span scenarios, effectively solving various technical problems faced by traditional cables in long-span applications.

[0039] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A large span tensile electric power cable, characterized in that, It includes a conductor layer and a sheath layer arranged successively from the inside to the outside, and a non-metallic strengthening member arranged parallel above the conductor layer; the conductor layer is concentrically stranded by multiple smooth-surface hard round metal wires; the cross-section of the sheath layer is in a symmetric U-shape, and the radius of curvature of its upper end face < the radius of curvature of its lower end face; the conductor layer is arranged below the centroid of the cable cross-section, and the strengthening member is arranged above the centroid of the cable cross-section.

2. The long span tensile strength power cable of claim 1, wherein, The conductor layer includes a strengthening core made by stranding multiple high-strength metal wires and an outer conductor wire made by stranding multiple high-conductivity metal wires coated outside the strengthening core.

3. The long span tensile strength power cable of claim 1, wherein, An elastic layer is coated outside the non-metallic strengthening member.

4. The long span tensile strength power cable of claim 1, wherein, Side ears are symmetrically arranged on both sides of the sheath layer.

5. The long span tensile strength power cable of claim 4, wherein, The side ears are in a U-shape, and the length of the lower side of the side ear ≤ the length of the upper side of the side ear.

6. The long span tensile strength power cable of claim 4, wherein, The side ears are triangular, and the length of the lower side of the side ear ≤ the length of the upper side of the side ear.

7. Long span tensile strength power cable according to any of the claims 4-6, characterized in that, The height of the connection line of the centroids of the two side ears is above the centroid of the cable cross-section.

8. The long span tensile strength power cable of claim 1, wherein, An anti-corrosion layer is further provided on the outer surface of the sheath layer.

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