A power cable with a large cross-section aluminum alloy conductor

Abstract

This utility model discloses a power cable with a large cross-section aluminum alloy conductor, comprising a single core, an armor layer, and an outer sheath layer. From the inside out, the single core includes a conductor, a semi-conductive layer, an insulation layer, a metallic shielding layer, a wrapping layer, and an inner sheath layer. The insulation layer, from the inside out, consists of a conductor shielding layer, an insulation layer, an insulating shielding layer, and a smooth electric field layer. This utility model features a reasonable cable structure, effectively improving electromagnetic shielding, reducing magnetic leakage, and ensuring a more uniform electric field distribution. This effectively reduces the risk of electrical treeing aging and breakdown, exhibiting excellent electric field distribution characteristics, and is suitable for large-section high-voltage transmission lines.

Description

Technical Field

[0001] This utility model relates to the field of power cables, specifically to a power cable with a large cross-section aluminum alloy conductor. Background Technology

[0002] As a crucial carrier of electrical energy, the performance and reliability of power cables directly affect the safe and stable operation of power systems. Aluminum alloy conductor power cables are widely used in power transmission due to their advantages such as light weight and low cost. Currently, common aluminum alloy conductor power cables on the market typically include a basic structure consisting of a conductor, insulation layer, shielding layer, and sheath layer.

[0003] In the prior art, CN105702325B discloses a lightweight power cable for ships and offshore oil platforms. Its main core, arranged radially from the inside out, comprises a conductor, a conductor shielding layer, an insulation layer, an insulating non-metallic shielding layer, and a metallic shielding layer. The conductor shielding layer, insulation layer, and insulating non-metallic shielding layer are co-extruded and wrapped around the outside of the conductor, with the metallic shielding layer wrapped around the insulating non-metallic shielding layer. CN114927270B discloses an aluminum alloy core cross-linked ethylene insulated low-smoke halogen-free polyolefin sheathed flame-retardant power cable. From the inside out, it includes a conductor, an inner conductor shielding layer, an insulation layer, an insulating shielding layer, a copper wire shielding layer, armor, and an outer sheath. The conductor is an aluminum alloy profile wrapped with a semi-conductive nylon tape, and the insulating shielding layer is wrapped with a semi-conductive nylon tape to form the shielding layer.

[0004] However, existing aluminum alloy conductor power cables still have the following technical problems:

[0005] First, existing cables have insufficient shielding performance and suffer from magnetic leakage. Traditional cables employ a semi-conductive layer and a metal shielding layer structure, but the conductivity of the aluminum alloy conductor and traditional stranding processes result in poor electromagnetic shielding effectiveness. In particular, aluminum tape wrapping shielding suffers from defects such as incomplete wrapping and curled edges, significantly increasing the probability of axial surface discharge. Large-section cables experience severe magnetic leakage during operation, causing electromagnetic interference and exacerbating energy loss.

[0006] Secondly, uneven electric field distribution increases the risk of breakdown. The skin effect of aluminum alloy conductors is significant, causing current to concentrate on the conductor surface and forming an uneven electric field distribution inside. This easily leads to electrical treeing aging and increases the risk of insulation breakdown.

[0007] In addition, the high porosity of traditional tightly stranded round conductors prevents the electromagnetic shielding layer from effectively adhering to the conductor surface, further increasing the leakage flux and affecting the overall performance and service life of the cable.

[0008] Therefore, there is an urgent need for a large-section aluminum alloy conductor power cable with excellent shielding performance, uniform electric field distribution, and reasonable structural design to solve the above-mentioned technical problems. Utility Model Content

[0009] The technical problem to be solved by this utility model is to provide a large-section aluminum alloy conductor power cable to address the shortcomings of existing aluminum alloy conductor cables, such as insufficient shielding performance, leakage magnetic field, uneven electric field distribution, breakdown risk, and structural design limitations, so as to improve the electromagnetic shielding effect, optimize the electric field distribution, and reduce the breakdown risk.

[0010] The technical solution adopted by this utility model to solve its technical problem is: to provide a power cable with a large cross-section aluminum alloy conductor, including a single core, an armor layer and an outer sheath layer. The single core includes, from the inside out, a conductor, a semi-conductive layer, an intermediate layer, a metal shielding layer, a wrapping layer and an inner sheath layer. The intermediate layer includes, from the inside out, a conductor shielding layer, an insulation layer, an insulation shielding layer and a smooth electric field layer.

[0011] A further preferred embodiment of this utility model is that the conductor shielding layer is a copper mesh woven from copper wires, with a thickness of 0.8mm ± 0.1mm.

[0012] A further preferred embodiment of this utility model is that the thickness of the insulating layer is 10.0±0.10mm, and the insulation eccentricity is ≤10%.

[0013] A further preferred embodiment of this utility model is that the insulating shielding layer is a copper mesh woven from copper wires, with a thickness of 0.8±0.2mm.

[0014] A further preferred embodiment of this utility model is that the smooth electric field layer is a semi-conductive non-woven fabric with a thickness ≥0.2mm and an overlap rate ≥45%.

[0015] A further preferred embodiment of this utility model is as follows: the conductor is an aluminum alloy circular compacted wire conductor; the semiconductive layer is a semiconductive nylon tape or carbon tape wrapped around the conductor; the metal shielding layer includes an inner shielding layer and an outer shielding layer; the inner shielding layer consists of several copper wires arranged in parallel at a certain helical angle; the outer shielding layer consists of several copper strips arranged in parallel at a certain helical angle, the helical angle of the copper strips being opposite to that of the copper wires; the wrapping layer is a semiconductive non-woven fabric; the armoring layer is a galvanized steel wire disposed outside the inner sheath layer; both the inner sheath layer and the outer sheath are made of PE.

[0016] A further preferred embodiment of this utility model is: the outer diameter of the conductor is 28.3±0.2mm, the minimum overlap of the semiconductive layer is ≥20%, the helix angle of the metal shielding layer is 5-45°, and the overlap of the wrapping layer is ≥45% and the wrapping thickness is ≥0.2mm.

[0017] A further preferred embodiment of this utility model is: an aluminum alloy conductor power cable with a large cross-section, comprising, from the inside out, three single cores as described in any one of the above, an armor layer, and an outer sheath layer.

[0018] The beneficial effects of this utility model are as follows:

[0019] 1. Through optimized metal shielding layer design, particularly the structural design where the inner and outer shielding layers have opposite helix angles, the electromagnetic shielding effect is effectively improved, and magnetic leakage is reduced. Compared with existing technologies, the cable structure of this invention significantly reduces the probability of axial surface discharge, thereby reducing electromagnetic interference and energy loss.

[0020] 2. By setting a multi-layer structure with a smooth electric field layer (semi-conductive non-woven fabric, overlap rate ≥45%) and an intermediate layer, the electric field distribution is more uniform, effectively reducing the risk of electrical treeing aging and breakdown. Compared with traditional structures, the cable structure of this invention can significantly reduce the probability of breakdown.

[0021] 3. By employing a stranded structure of aluminum alloy circular compressed conductors and a multi-layer shielding design, the porosity is reduced, allowing the electromagnetic shielding layer to adhere more effectively to the conductor surface and lowering the magnetic leakage rate. This utility model's cable structure effectively overcomes the magnetic leakage problem present in traditional structures while maintaining the advantages of aluminum alloy conductors. Attached Figure Description

[0022] Figure 1 This is a cable structure diagram of Example 1;

[0023] Figure 2 This is a cable structure diagram for Example 2;

[0024] Conductor 1, Semiconductor layer 2, Intermediate layer 3, Conductor shielding layer 31, Insulating layer 32, Insulating shielding layer 33, Smooth electric field layer 34, Metal shielding layer 4, Wrapping layer 5, Inner sheath layer 6, Armoring layer 7, Outer sheath layer 8, Filler layer 9. Detailed Implementation

[0025] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0026] Example 1

[0027] A power cable with a large cross-section aluminum alloy conductor includes a single core, an armor layer 7, and an outer sheath layer 8. The single core, from the inside out, comprises a conductor 1, a semi-conductive layer 2, an intermediate layer 3, a metallic shielding layer 4, a wrapping layer 5, and an inner sheath layer 6. The intermediate layer, from the inside out, comprises a conductor shielding layer 31, an insulation layer 32, an insulation shielding layer 33, and a smooth electric field layer 34.

[0028] The conductor uses 8000 series aluminum alloy round compacted wire conductors with a standard outer diameter of 28.3mm and an allowable error range of ±0.2mm. The conductor's DC resistance at 20℃ is ≤0.0469Ω / km. Aluminum alloy conductors have advantages such as light weight, good conductivity, and low cost, making them suitable for the manufacture of large-section power cables.

[0029] The semiconductive layer is made by wrapping a semiconductive nylon tape, such as nylon tape or carbon tape, around the outer surface of the conductor. The minimum overlap rate is 20%. The function of the semiconductive layer is to uniformly distribute the electric field on the conductor surface and prevent partial discharge.

[0030] The conductor shielding layer is a copper mesh woven from fine copper wires, with a standard thickness of 0.8mm and an allowable error range of ±0.1mm. The copper wire braided structure effectively shields against electromagnetic interference, improving the cable's anti-interference capability.

[0031] The insulation layer uses PPLP (polypropylene film-impregnated paper-polypropylene film) material with a standard thickness of 10.0 mm, an allowable error range of ±0.10 mm, and an insulation eccentricity of no more than 10%. PPLP insulation material has excellent electrical insulation properties and mechanical strength, which can meet the insulation requirements of large-section power cables.

[0032] The insulating shielding layer is a copper mesh woven from fine copper wires, with a standard thickness of 0.8 mm and an allowable error range of ±0.2 mm. The insulating shielding layer has a similar structure to the conductor shielding layer, but it is located on the outside of the insulating layer and is used to shield against external electromagnetic interference.

[0033] The thickness of the smooth electric field layer should be no less than 0.2 mm, and the overlap rate should be no less than 45%. Semi-conductive non-woven fabric can be used. The function of the smooth electric field layer is to uniformly distribute the electric field on the outer surface of the insulation layer, reduce electric field concentration, and improve the insulation performance of the cable.

[0034] The metallic shielding layer comprises an inner shielding layer and an outer shielding layer. The inner shielding layer consists of several parallel copper wires arranged at a certain helical angle, while the outer shielding layer consists of several parallel copper strips arranged at a certain helical angle. The helical angles of the copper strips and copper wires are opposite, ranging from 5° to 45°. In this embodiment, the copper wires have a diameter of 0.85 mm, number 34, and a minimum diameter requirement of 0.83 mm. They are secured to the inner shielding layer using copper strips or non-woven fabric tape. The copper strips are 0.10 mm thick and 40 mm wide, with a minimum thickness requirement of 0.09 mm and a minimum overlap rate of 5%. This double-layer design of the metallic shielding layer enhances the cable's mechanical strength and anti-interference capability.

[0035] The wrapping layer is a semi-conductive non-woven fabric. In this embodiment, the non-woven fabric is 0.2 mm thick and 80 mm wide, with an overlap rate of not less than 20%. The function of the wrapping layer is to protect the internal structure, provide mechanical cushioning, and further shield against electromagnetic interference.

[0036] The inner sheath is made of PE (polyethylene) material with a thickness ranging from 2.1 to 2.9 mm; in this embodiment, it is 2.9 mm. The inner sheath provides excellent mechanical protection and waterproof performance. The inner sheath covers the outside of the wrapping layer, providing protection for the internal structure of the cable.

[0037] The armor layer consists of galvanized steel wire placed outside the inner sheath. Galvanized steel wire possesses high mechanical strength and corrosion resistance, effectively protecting the internal structure of the cable and improving its tensile strength and resistance to external impacts. In this embodiment, the galvanized steel strip is 0.8 mm thick and 60 mm wide, with a minimum overlap of 50%.

[0038] The outer sheath is made of MDPE (polyethylene), which has excellent weather resistance, corrosion resistance, and mechanical protection properties, effectively protecting the internal structure of the cable from the influence of the external environment. In this embodiment, the outer sheath thickness is 5.3 mm.

[0039] The power cable structure in this embodiment is reasonably designed, and the materials selected for each layer are appropriate, which can meet the electrical and mechanical performance requirements of large-section power cables and is suitable for high-voltage transmission lines.

[0040] Example 2

[0041] The difference between this embodiment and Embodiment 1 is that in this embodiment, the three single-core cables are jointly covered by an armor layer and an outer sheath layer. A filler layer 9, such as a filler rope, can be placed in the gap between the single core and the armor layer to ensure the cable's strength while protecting the single core. Compared to the single-core structure, the three-core structure is easier to install, occupies less space, and is suitable for applications with limited space. Withstand voltage and partial discharge tests were conducted on the cable of this embodiment, and it was found that it did not break down at 91KV / 5min and no discharge was detected at 45KV, meeting the usage requirements.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A power cable with a large cross-section aluminum alloy conductor, comprising a single core, an armor layer, and an outer sheath layer, wherein the single core comprises, from the inside out, a conductor, a semi-conductive layer, an intermediate layer, a metal shielding layer, a wrapping layer, and an inner sheath layer, characterized in that, The intermediate layer consists of, from the inside out, a conductor shielding layer, an insulating layer, an insulating shielding layer, and a smooth electric field layer. The conductor is a round, tightly compressed aluminum alloy conductor; the semiconductive layer is a semiconductive nylon or carbon tape wrapped around the conductor; the metal shielding layer includes an inner shielding layer and an outer shielding layer; the inner shielding layer consists of several parallel copper wires arranged at a certain helical angle; the outer shielding layer consists of several parallel copper strips arranged at a certain helical angle, with the helical angle of the copper strips opposite to that of the copper wires; the wrapping layer is a semiconductive non-woven fabric; the armor layer is a galvanized steel wire disposed outside the inner sheath layer; both the inner and outer sheaths are made of PE.

2. The power cable of claim 1, wherein, The conductor shielding layer is a copper mesh woven from copper wires, with a thickness of 0.8mm ± 0.1mm.

3. The power cable of claim 2, wherein, The insulation layer is PPLP with a thickness of 10.0±0.10mm and an insulation eccentricity of ≤10%.

4. The power cable of claim 3, wherein, The insulating shielding layer is a copper mesh woven from copper wires, with a thickness of 0.8±0.2mm.

5. The power cable of claim 4, wherein, The smooth electric field layer is a semi-conductive non-woven fabric with a thickness ≥0.2mm and an overlap rate ≥45%.

6. The power cable of claim 1, wherein, The conductor has an outer diameter of 28.3±0.2mm, the semiconductive layer has a minimum overlap of ≥20%, the metal shielding layer has a helix angle of 5-45°, and the wrapping layer has an overlap of ≥45% and a wrapping thickness of ≥0.2mm.

7. An aluminum alloy conductor power cable having a large cross section, characterized by, From the inside out, it includes three aluminum alloy conductor power cables with large cross-sections as described in any one of claims 1-6.

Images