Corrugated seven-segment cable core structure, cable structure and production process

Abstract

The invention discloses a corrugated seven-segment cable core structure, a cable structure and a production process, the corrugated seven-segment cable core structure comprises a central conductor and seven tile-shaped separation strand block conductors, and the seven tile-shaped separation strand block conductors are twisted around the central conductor to form a cable core with a circular cross section; the center conductor and the tile-shaped separation strand block conductors are isolated through graphene insulation paper, and the adjacent tile-shaped separation strand block conductors are isolated through graphene insulation paper. According to the invention, the current transmission channel is obviously increased. Meanwhile, the current transmission capability of the cable is improved by adopting a central conductor and seven-segment corrugated split conductor structure; the insulation paper doped with the graphene is used in the cable conductor, and the graphene has extremely low relative permeability, so that the magnetic flux density in the conductor is reduced, the heat energy generated by the action of a magnetic field is reduced, and the current-carrying capacity and the working efficiency of the cable are improved; and meanwhile, the current can be more uniformly distributed in the conductor, the alternating-current resistance and phase loss of the cable core are reduced, and the transmission efficiency of the cable is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of cable core structure design, and in particular to a corrugated seven-section cable core structure, a cable structure and a production process. Background Art

[0002] Skin effect refers to the interaction between electric field and magnetic field under the action of high-frequency electromagnetic field, which makes the electric field gather on the surface of the conductor, thus generating strong surface current and electric field. This phenomenon is called skin effect. Because of the existence of skin effect, the current tends to flow through the surface of the conductor rather than the entire cross-section of the conductor, which means that only the resistance on the surface of the conductor will generate actual current.

[0003] The current transmission capacity of the conductor does not increase linearly with the increase of the conductor cross section. This phenomenon is caused by the "skin effect" and "proximity effect" of the conductor in the process of transmitting AC current. As the conductor cross section increases, this phenomenon will become more and more significant. Therefore, the 110-220kV cross-linked polyethylene insulated high-voltage and ultra-high-voltage power cable standards "Rated voltage 110kV cross-linked polyethylene insulated cable and its accessories" and "Rated voltage 220kV (Um=252kV) cross-linked polyethylene insulated cable and its accessories" clearly stipulate that the cross section of the cable should be 800mm 2 The above cable conductors must use split conductors to reduce the influence of the increase in cable conductor resistance caused by the "skin effect" and "proximity effect" on the transmission energy.

[0004] The size of the cable cross-sectional area affects the degree of skin effect. For larger cable cross-sectional areas, the current distribution inside the conductor will be more complicated due to the increase in the conductor cross-section, and the skin effect will be more obvious. This means that in high-frequency circuits or high-current loads, a larger cable cross-sectional area may cause the current distribution inside the conductor to be more uneven, thereby increasing the resistance and power loss of the cable and reducing the transmission efficiency of the cable. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a corrugated seven-section cable core structure, a cable structure and a production process, so that the current can be more evenly distributed in the conductor, the AC resistance and phase loss of the cable core are reduced, and the transmission efficiency of the cable is enhanced.

[0006] The technical solution of the present invention is as follows:

[0007] In the first aspect of the present invention, a corrugated seven-section cable core structure is provided, comprising a central conductor and seven tile-shaped separating strand block conductors, wherein the seven tile-shaped separating strand block conductors are twisted around the central conductor to form a cable core with a circular cross-section; the central conductor and the tile-shaped separating strand block conductors, as well as adjacent tile-shaped separating strand block conductors, are isolated by graphene insulating paper.

[0008] In some embodiments of the present invention, the cross-sectional area of ​​the cable core is 4000-5000mm 2 .

[0009] In some embodiments of the present invention, the thickness of the graphene insulation paper is 0.2-0.5 mm.

[0010] In some embodiments of the present invention, the central conductor and the tile-shaped separator block conductor are both formed by twisting aluminum wires with a radius of 1.3-1.8 mm.

[0011] In some embodiments of the present invention, each tile-shaped separator block conductor has the same size and the same twisting direction.

[0012] In the second aspect of the present invention, a corrugated seven-segment cable structure is provided, comprising the corrugated seven-segment cable core structure described in the first aspect, wherein a tape layer, a conductor shielding layer, an insulating layer, an insulating shielding layer, a water-blocking tape layer, an aluminum alloy layer, a hot-melt adhesive layer, an outer sheath layer and an outer electrode layer are sequentially arranged on the outside of the cable core.

[0013] In a third aspect of the present invention, a production process of a corrugated seven-section cable structure is provided, comprising:

[0014] According to the cross-sectional area of ​​the cable core, determine the cross-sectional area of ​​the center conductor and the tile-shaped separator block conductor, and prepare the corresponding number of aluminum wires;

[0015] A central conductor and seven tile-shaped separator block conductors are manufactured, and then the central conductor and the tile-shaped separator block conductor and adjacent tile-shaped separator block conductors are isolated by using graphene insulation paper;

[0016] Seven tile-shaped separator block conductors are twisted together on the central conductor to obtain the cable core.

[0017] In some embodiments of the present invention, when manufacturing the center conductor and the seven tile-shaped separation strand block conductors, the insulation paper is firstly half-wrapped on the strand block and then twisted into a cable.

[0018] In some embodiments of the present invention, before the central conductor and the tile-shaped separation strand block conductor are twisted together using aluminum wires, the aluminum wires are pre-twisted to initially form an arrangement.

[0019] In some embodiments of the present invention, after the cable core is obtained, the cable core is subjected to a compacting process.

[0020] One or more technical solutions of the present invention have the following beneficial effects:

[0021] (1) The cable core structure provided by the present invention can effectively increase the cable core area to 4000-5000mm 2 , significantly increasing the current transmission channel. At the same time, the central conductor plus seven-segment corrugated split conductor structure is adopted. This unique design allows the current to be more evenly distributed in the conductor, effectively improving the current transmission capacity of the cable.

[0022] (2) The present invention uses insulating paper doped with graphene in the cable conductor. Graphene, as an advanced material, has an extremely low relative magnetic permeability (about 0.1), which can effectively reduce the magnetic permeability of the insulating paper. This change not only reduces the magnetic flux density in the conductor, but also reduces the heat energy generated by the magnetic field, thereby further improving the current carrying capacity and working efficiency of the cable.

[0023] (3) The present invention effectively reduces the impact of the skin effect on cable current transmission by adopting the synergistic effect of the seven-segment conductor structure and low magnetic permeability insulating paper. The skin effect is a physical phenomenon, which refers to the phenomenon that the current is concentrated near the surface of the conductor under the action of the AC electric field. It will cause the current to concentrate on the surface of the conductor, increase the resistance and reduce the current carrying capacity of the conductor. The corrugated center conductor plus the seven-segment conductor also has a significant effect on reducing the impact of the skin effect, allowing the current to be more evenly distributed in the conductor, reducing the AC resistance and phase loss of the cable core, enhancing the transmission efficiency of the cable, and significantly improving the practicality and reliability of the cable.

[0024] (4) By designing the cable conductor as a central conductor plus a seven-segment corrugated segmented conductor, and adding low magnetic permeability insulation paper to control the magnetic field morphology of the core, the loss heating of the conductor and the influence of the skin effect are effectively reduced, and the current carrying capacity of the conductor is increased. This is because the characteristics of graphene insulation paper play a key role in reducing the loss heating of the conductor. Due to the low magnetic permeability, the insulation paper can effectively reduce the magnetic flux density in the conductor, thereby reducing the heat energy generated by the magnetic field. This change directly affects the current carrying capacity of the cable core. Due to the reduction in temperature, the cable core can withstand a higher current load, thereby increasing the working efficiency and stability of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a diagram of the cable core structure in Example 1;

[0026] Figure 2 This is a cable structure diagram in Example 2;

[0027] Figure 3 For the existing 3500mm 2 Current density distribution diagram of five-section corrugated cable core;

[0028] Figure 4 For the existing 4500mm 2 Current density distribution diagram of five-section corrugated cable core;

[0029] Figure 5 The new 4500mm 2 Seven-section cable core current density distribution diagram;

[0030] Figure 6 For the existing 3500mm 2 Magnetic flux density distribution diagram of five-section corrugated cable core;

[0031] Figure 7 For the existing 4500mm 2 Magnetic flux density distribution diagram of five-section corrugated cable core;

[0032] Figure 8 The new 4500mm 2 Seven-section cable core magnetic flux density distribution diagram;

[0033] Fig. 9 For the existing 3500mm 2 Corrugated cable, existing 4500mm 2 Corrugated cable, the new 4500mm 2 Comparison chart of current carrying capacity of seven-section cables;

[0034] Fig.10 For the existing 3500mm 2 Corrugated cable, existing 4500mm 2 Corrugated cable, the new 4500mm 2 Comparison chart of AC resistance of seven-section cables;

[0035] Fig.11 For the existing 3500mm 2 Corrugated cable, existing 4500mm 2 Corrugated cable, the new 4500mm 2 Phase loss comparison chart of seven-segment cable.

[0036] In the figure: 1. Center conductor; 2. Tile-shaped separator block conductor; 3. Graphene insulation paper; 4. Tape; 5. Conductor shielding layer; 6. Insulation layer; 7. Insulation shielding layer; 8. Water-blocking tape layer; 9. Aluminum alloy layer; 10. Hot melt adhesive layer; 11. Outer sheath layer; 12. Outer electrode layer. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0038] Example 1

[0039] In a typical embodiment of the present invention, a corrugated seven-segment cable core structure is proposed, such as Figure 1 As shown, it includes a central conductor 1 and seven tile-shaped separating strand conductors 2. The seven tile-shaped separating strand conductors 2 are twisted around the central conductor 1 to form a cable core with a circular cross-section. The central conductor 1 and the tile-shaped separating strand conductors 2 and adjacent tile-shaped separating strand conductors 2 are isolated by graphene insulating paper 3.

[0040] In this embodiment, the cross-sectional area of ​​the cable core is 4000-5000mm 2 Preferably, the cross-sectional area of ​​the cable core is 4500mm 2 .

[0041] In this embodiment, the thickness of the graphene insulating paper is 0.2-0.5 mm, preferably, the thickness of the graphene insulating paper is 0.4 mm. By using insulating paper doped with graphene, graphene, as an advanced material, has an extremely low relative magnetic permeability (about 0.1), which can effectively reduce the magnetic permeability of the insulating paper. This change not only reduces the magnetic flux density in the conductor, but also reduces the heat energy generated by the magnetic field, thereby further improving the current carrying capacity and working efficiency of the cable.

[0042] In this embodiment, the central conductor and the tile-shaped separating strand block conductor are both formed by twisting aluminum wires with a radius of 1.3-1.8 mm. Preferably, the radius of the aluminum wire is 1.5 mm.

[0043] In this embodiment, each tile-shaped separator block conductor has the same size and the same twisting direction.

[0044] 4500mm 2 Taking enameled wire cable as an example, the cross-sectional area of ​​the central conductor is 315mm 2 The cross-sectional area of ​​the tile-shaped separator block conductor is 600mm 2 ,The parameters of the graphene insulation paper used are shown in Table 1:

[0045] Table 1 Parameters of graphene insulation paper

[0046] Relative magnetic permeability Conductivity S / m Thermal conductivity W / mk Thickness mm Antimagnetic insulation paper 0.1 1e-14 5300 0.4

[0047] The existing 3500mm 2 Corrugated cable, existing 4500mm 2 Corrugated cable, the new 4500mm2 Seven-section cable for comparison:

[0048] The current density distribution diagram obtained is shown in Figure 3-5 As shown, the new 4500mm 2 The maximum current density of the seven-section corrugated cable is 9.1×105A / m 2 , normal 3500mm 2 The maximum current density of the five-section corrugated cable is 1.22×106A / m 2 The new cable current density is reduced by 310000A / m 2 , reduced by 25.41%. Normal 4500mm 2 The maximum current density of the five-section corrugated cable is 1.15×106A / m 2 The new cable current density is reduced by 240000A / m 2 , which is reduced by 20.87%. This means that in the new cable, the current distribution in the conductor becomes more uniform. It can be clearly seen from the chart that the skin effect of the new cable has been significantly reduced. This may be due to the fact that the current distribution in the conductor becomes more uniform and dispersed under the effect of low magnetic permeability insulation paper and multi-split strand blocks.

[0049] The magnetic flux density distribution diagram obtained is as follows: Figure 6-8 As shown, the core magnetic field of the ordinary cable presents a uniform diffusion pattern. This means that the magnetic field spreads uniformly from the center of the core outward, without obvious concentration or dispersion. However, when turning to the new cable structure of this embodiment, the situation changes significantly. Due to the addition of graphene insulation paper in the core, this special material changes the behavior of the magnetic field, which makes the magnetic field of the core shrink inward a little with each strand block as the boundary.

[0050] The current carrying capacity comparison chart obtained is as follows Fig. 9 As shown, through data comparison, it can be found that the new 4500mm 2 The current carrying capacity of the seven-section corrugated cable is 2170A, and the common 3500mm 2 The current carrying capacity of the five-section corrugated cable is 2000A, and the current carrying capacity of the new cable has increased by 170A, an increase of 8.5%. 2 The current carrying capacity of the five-section corrugated cable is 2120A. The current carrying capacity of the new cable has increased by 50A, an increase of 2.36%.

[0051] The existing 3500mm 2 Corrugated cable, existing 4500mm 2 Corrugated cable, the new 4500mm 2The current carrying capacity, AC resistance and phase loss data of the seven-section cable are shown in Table 2 below:

[0052] Table 2 Data on current carrying capacity, AC resistance and phase loss

[0053] Current carrying capacity A AC resistance Ω / km Phase loss W / m <![CDATA[3500mm 2 Five-section corrugated cable]]> 2000 0.013563 29.641 <![CDATA[4500mm 2 Five-section corrugated cable]]> 2120 0.011942 29.437 <![CDATA[New type 4500mm 2 Seven-segment corrugated cable]]> 2170 0.011693 22.775

[0054] The AC resistance comparison chart is as follows: Fig.10 As shown, the new 4500mm 2 The AC resistance of the seven-section corrugated cable is 0.011693Ω / km, and the ordinary 3500mm 2 The AC resistance of the five-section corrugated cable is 0.013563Ω / km, and the AC resistance of the new cable is reduced by 0.00187Ω / km, a reduction of 13.79%. 2 The AC resistance of the five-section corrugated cable is 0.011942Ω / km, and the AC resistance of the new cable is reduced by 0.000249Ω / km, a reduction of 2.09%.

[0055] The obtained phase loss comparison diagram is as follows: Fig.11 As shown, the new 4500mm 2 The phase loss of the seven-segment corrugated cable is 22.775W / m, and the ordinary 3500mm 2 The phase loss of the five-section corrugated cable is 26.641W / m, and the phase loss of the new cable is reduced by 3.866W / m, a reduction of 14.51%. Ordinary 4500mm 2 The phase loss of the five-section corrugated cable is 29.437W / m, and the phase loss of the new cable is reduced by 6.662W / m, a reduction of 22.63%.

[0056] The corrugated seven-segment cable core structure provided in this embodiment adopts a seven-segment conductor structure and low magnetic permeability insulating paper, and the present invention effectively reduces the influence of the skin effect on the current transmission of the cable. The skin effect is a physical phenomenon that causes the current to concentrate on the surface of the conductor, increasing the resistance and reducing the current carrying capacity of the conductor. The design of the present invention enables the current to be more evenly distributed in the conductor, reducing the AC resistance and phase loss of the cable core, and enhancing the transmission efficiency of the cable.

[0057] Example 2

[0058] In a typical embodiment of the present invention, a corrugated seven-segment cable structure is provided, including the corrugated seven-segment cable core structure described in Example 1, such as Figure 2 As shown, the outer surface of the cable core is provided with a tape layer 4, a conductor shielding layer 5, an insulating layer 6, an insulating shielding layer 7, a water-blocking tape layer 8, an aluminum alloy layer 9, a hot-melt adhesive layer 10, an outer sheath layer 11 and an outer electrode layer 12 in sequence.

[0059] Example 3

[0060] In a typical embodiment of the present invention, a production process of a corrugated seven-segment cable core structure is provided, comprising:

[0061] According to the cross-sectional area of ​​the cable core, determine the cross-sectional area of ​​the center conductor and the tile-shaped separator block conductor, and prepare the corresponding number of aluminum wires;

[0062] A central conductor and seven tile-shaped separator block conductors are manufactured, and then the central conductor and the tile-shaped separator block conductor and adjacent tile-shaped separator block conductors are isolated by using graphene insulation paper;

[0063] Seven tile-shaped separator block conductors are twisted on the central conductor to obtain the cable core. During the twisting process, the tension of the pay-off reel is ensured to be uniform, and the position of the separator block is adjusted so that the top angle of the separator block is always aligned with the geometric center of the cable during the cabling process, and the separator block is prevented from turning over to ensure that the separator conductors are cabled in a round shape.

[0064] Furthermore, when manufacturing the central conductor and the seven tile-shaped separating strand block conductors, the insulating paper is first half-wrapped on the strand block, and then twisted into a cable. Specifically, when each strand block conductor and the central conductor are in the cabling process, a 0.40mm insulating paper is continuously introduced into the inner side of the dividing block, and a layer of insulating paper is added every other dividing block to enhance its insulation performance. After twisting into a cable, the cable core is pressed tightly. To ensure the compactness and roundness of the twisted core, this step is completed by a mechanical device. The core is a tightly pressed circle, and the twisting must be uniform, round, and tight, without loose strands, missing strands, back strands, or broken strands.

[0065] Furthermore, before the central conductor and the tile-shaped separated strand block conductor are twisted with aluminum wires, the aluminum wires are pre-twisted to form a preliminary arrangement to ensure that the single wires can form an expected arrangement during the twisting process. During the preparation of the central conductor and the tile-shaped separated strand block conductor, the single wires are twisted in the left direction according to the twisting direction of each twisted layer using a twisting machine.

[0066] In a specific embodiment, the cross-sectional area of ​​the cable core is 4500mm 2 When the cross-sectional area of ​​the central conductor is 315mm 2 The cross-sectional area of ​​the tile-shaped separator block conductor is 600mm 2 The radius of the aluminum wire used is 1.5mm.

[0067] Furthermore, after obtaining the cable core, the cable core is pressed tightly to ensure the compactness and roundness of the twisted core, which is completed by a mechanical device.

[0068] In addition, in the production process, the twisted conductive wire core also has specific quality requirements, such as the twisted wire core should be tight, round, straight, without severe bends, no skipped strands, no scratches, no flattening, the surface of the aluminum wire should not be oxidized, blackened, the tinned wire layer should not fall off or tin particles, the pitch should be uniform, the joints should be flat and firm, and the wiring should be neat.

[0069] The strands should be twisted evenly and tightly, without loose strands, missing strands, back strands, broken strands, oil stains, burrs, sharp edges, scratches, bulges, etc. No joints are allowed on the outer layer, and the inner layer joints are made by resistance welding or cold pressure welding. The distance between two adjacent joints should be no less than 1.5m. All joints should be firm, smooth, and without obvious bulges.

[0070] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A corrugated seven-section cable core structure, characterized in that: It comprises a central conductor and seven tile-shaped separating strand-block conductors, wherein the seven tile-shaped separating strand-block conductors are twisted around the central conductor to form a cable core with a circular cross-section; the central conductor and the tile-shaped separating strand-block conductors and adjacent tile-shaped separating strand-block conductors are isolated by graphene insulating paper.

2. The corrugated seven-section cable core structure according to claim 1, characterized in that: The cross-sectional area of ​​the cable core is 4000-5000mm 2 .

3. The corrugated seven-section cable core structure according to claim 1, characterized in that: The thickness of the graphene insulating paper is 0.2-0.5 mm.

4. The corrugated seven-section cable core structure according to claim 1, characterized in that: The central conductor and the tile-shaped separation strand block conductor are both formed by twisting aluminum wires with a radius of 1.3-1.8 mm.

5. The corrugated seven-section cable core structure according to claim 4, characterized in that: Each tile-shaped separator block conductor has the same size and the same twisting direction.

6. A corrugated seven-segment cable structure, comprising the corrugated seven-segment cable core structure according to any one of claims 1 to 5, characterized in that: The outer surface of the cable core is sequentially provided with a tape layer, a conductor shielding layer, an insulating layer, an insulating shielding layer, a water-blocking tape layer, an aluminum alloy layer, a hot-melt adhesive layer, an outer sheath layer and an outer electrode layer.

7. A production process for a corrugated seven-section cable core structure as claimed in any one of claims 1 to 5, characterized in that: include: According to the cross-sectional area of ​​the cable core, determine the cross-sectional area of ​​the center conductor and the tile-shaped separator block conductor, and prepare the corresponding number of aluminum wires; A central conductor and seven tile-shaped separator block conductors are manufactured, and then the central conductor and the tile-shaped separator block conductor and adjacent tile-shaped separator block conductors are isolated by using graphene insulation paper; Seven tile-shaped separator block conductors are twisted together on the central conductor to obtain the cable core.

8. The production process of the corrugated seven-section cable core structure according to claim 7, characterized in that: When manufacturing the center conductor and the seven tile-shaped separator strands, the insulating paper is first half-wrapped on the strands and then twisted into cables.

9. The production process of the corrugated seven-section cable core structure according to claim 7, characterized in that: Before the central conductor and the tile-shaped separation strand block conductor are twisted together with aluminum wires, the aluminum wires are pre-twisted to form a preliminary arrangement.

10. The production process of the corrugated seven-section cable core structure according to claim 7, characterized in that: After obtaining the cable core, the cable core is pressed tightly.

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