Waterproof corrugated aluminum sleeve high voltage cable and production method thereof
By adding a copper wire water-blocking layer between the aluminum sheath and the water-blocking buffer layer of the high-voltage cable, the problem of electrochemical corrosion of the cable under humid conditions is solved, the water-blocking and thermal conductivity are improved, and the safe and stable operation of the cable is ensured.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHONGQING TAISHAN CABLE CO LTD
- Filing Date
- 2023-04-17
- Publication Date
- 2026-07-24
AI Technical Summary
Under humid conditions, the water-blocking buffer layer and the corrugated aluminum sheath of high-voltage cables undergo electrochemical corrosion, producing insulating white powder, which leads to increased resistance and heat accumulation, threatening the safe operation of the power grid.
A copper wire water-blocking layer, including round copper wire and flat copper wire, is added between the aluminum sheath and the water-blocking buffer layer. The round copper wire is wrapped with a water-blocking tape, and the flat copper wire is located at the groove of the aluminum sheath. The spiral groove is formed by the rolling cutter to tightly fix the copper wire, improve the thermal and electrical conductivity, and avoid electrochemical reactions.
It improves the longitudinal water-blocking performance and thermal conductivity of the cable, reduces the probability of electrochemical reactions, ensures that the cable's bending performance is not affected, and reduces the risk of heat accumulation.
Smart Images
Figure CN116580885B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cable design technology, and in particular to a water-blocking corrugated aluminum-sheathed high-voltage cable and its manufacturing method. Background Technology
[0002] With the accelerating pace of global urbanization and the ever-increasing demand for electricity, higher requirements are being placed on cable systems used in power transmission. Extruded XLPE insulated cables, with their excellent electrical performance, large transmission capacity, light weight, simple manufacturing process, and convenient installation and maintenance, have become the main form of high-voltage AC power cables. Corrugated aluminum sheaths are widely used in high-voltage XLPE insulated cables due to their good bending performance. Most high-voltage XLPE cables used in China and even Southeast Asia adopt a corrugated aluminum sheath structure, with a buffer layer added between the metal sheath and the insulated core. The buffer layer often uses a sponge-like tape made of semi-conductive polyester non-woven fiber cloth, while water-blocking buffer layers consist of semi-conductive non-woven fabric and semi-conductive fluffy cotton, with a layer of water-blocking powder in between.
[0003] Related research indicates that under humid conditions, high-voltage power cables experience electrochemical corrosion between the water-blocking buffer layer and the corrugated aluminum sheath. This generates a large amount of white insulating powder between the insulation shield, the water-blocking buffer layer, and the corrugated aluminum sheath. This white powder not only hinders effective grounding of the insulation shield, creating safety hazards, but the accumulated powder can also cause damage to the insulation shield or even the insulating medium due to heat or discharge, directly leading to cable breakdown accidents and threatening the safe operation of the power grid. The main reason for this problem is that the buffer layer material is prone to moisture absorption. Moisture can react electrochemically with aluminum to produce white powder, increasing resistance. This increased resistance leads to increased heat generation in this area, and the inability to dissipate this accumulated heat further exacerbates the problem.
[0004] Therefore, those skilled in the art are dedicated to developing a water-blocking corrugated aluminum-sheathed high-voltage cable and its production method that improves the water-blocking effect and thermal conductivity of the cable buffer layer without affecting the cable's bending performance. Summary of the Invention
[0005] In view of the above-mentioned defects of the prior art, the present invention discloses a water-blocking corrugated aluminum sheathed high-voltage cable and its manufacturing method. The technical problem to be solved is to provide a water-blocking corrugated aluminum sheathed high-voltage cable and its manufacturing method that improves the water-blocking effect and thermal conductivity of the cable buffer layer without affecting the bending performance of the cable.
[0006] To achieve the above objectives, the present invention provides a water-blocking corrugated aluminum-sheathed high-voltage cable, including a water-blocking buffer layer. The outer side of the water-blocking buffer layer is an aluminum sheath with spiral grooves. A copper wire water-blocking layer is provided between the aluminum sheath and the water-blocking buffer layer. The copper wire water-blocking layer includes round copper wires and flat copper wires arranged sequentially. The flat copper wires are located at the grooves of the aluminum sheath. The round copper wires and flat copper wires are naturally connected and appear continuously at intervals.
[0007] Preferably, the round copper wire is sheathed with a water-blocking tape, which can be water-blocking yarn, i.e., water-blocking yarn loosely wound on the copper wire. The thickness of the water-blocking tape is 1.2-1.8mm, preferably 1.5mm. Since the copper wire is located close to the corrugated aluminum sleeve, the expansion volume of the water-blocking tape is generally more than twice the thickness of the tape. Designing a water-blocking tape thickness of 1.5mm can balance water-blocking performance and material consumption.
[0008] Preferably, the flat copper wire is a bare copper wire, and the water-blocking strip on the flat copper wire is peeled off to form a section of round copper wire with a water-blocking layer consisting of a water-blocking strip and a section of bare flat copper wire. This design allows the round copper wire to bend more easily to support the expansion of the water-blocking strip, and the flat copper wire, after being rolled, has a larger contact area with the water-blocking buffer layer, improving thermal and electrical conductivity in this area. The larger surface area also prevents the round copper wire from easily embedding into the water-blocking buffer layer. The rougher surface after rolling also increases surface friction, preventing slippage of the flat copper wire and allowing it to bend precisely at the rolled area. The selected copper wire typically has a tensile strength of 250–380 MPa and is in a non-annealed state to ensure sufficient support within the gap.
[0009] The water-blocking corrugated aluminum-sheathed high-voltage cable provided by the present invention further includes an insulated core, wherein the insulated core includes a conductor layer and an insulation layer, and the water-blocking buffer layer is located outside the insulation layer.
[0010] Preferably, the conductor layer is formed into a cylinder by stranding copper or aluminum wires, and the outside of the conductor layer has a semi-conductive material.
[0011] Preferably, the insulating layer is formed by extruding cross-linked polyethylene material and semi-conductive material around the conductor layer.
[0012] Preferably, the water-blocking buffer layer comprises a semi-conductive non-woven fabric and a semi-conductive fluffy cotton, with water-blocking powder filling the space between the semi-conductive non-woven fabric and the semi-conductive fluffy cotton.
[0013] Preferably, the length of the round copper wire is 2 to 5 times the length of the flat copper wire, preferably 3 times, and the ratio can also be adjusted according to the depth of the rolled groove.
[0014] The present invention also provides a method for producing a water-blocking corrugated aluminum sheathed high-voltage cable, the method comprising the following steps:
[0015] 1) Produce the copper wire water-blocking layer, the insulated wire core, and the aluminum sheath separately, and wrap the water-blocking tape around the insulated wire core to form a water-blocking buffer layer. The water-blocking buffer layer is formed by wrapping the water-blocking tape through a wrapping machine. Generally, about 3 layers are wrapped. Two methods can be selected: overlapping wrapping and gap wrapping.
[0016] 2) Aluminum sheathed longitudinally wrapped insulated wire core and water-blocking buffer layer: The insulated wire core wrapped with the water-blocking buffer layer is fed into the aluminum sheath, and the copper wire water-blocking layer is guided into the space between the water-blocking buffer layer and the aluminum sheath by an adjustable wire feeding wheel; the adjustable wire feeding wheel can not only adjust the feeding position of the copper wire water-blocking layer, but also control its feeding tension. The feeding tension is controlled by adjusting the ratio of the feeding speed of the adjustable wire feeding wheel to the feeding speed of the conductor. By adjusting these two parameters, the degree of bending of the copper wire in the gap can be adjusted.
[0017] 3) The aluminum sheath is welded into a cylindrical shape using an argon arc welding machine. Then, spiral grooves are rolled onto the aluminum sheath using a rolling cutter. The distance that the rolling cutter deforms the aluminum sheath is greater than the gap between the aluminum sheath and the water-blocking buffer layer. Therefore, the water-blocking buffer layer will be deformed by compression, resulting in a depression at the contact area and a bulge at the gap area. The copper wire water-blocking layer is located between the buffer water-blocking layer and the wrinkled aluminum sheath and is tightly fixed at the contact position. The round copper wire with water-blocking strip at the gap area will bend naturally due to the downward pressure of the rolling cutter.
[0018] 4) An outer sheath and a semi-conductive layer are extruded over the aluminum sheath. The outer sheath and the semi-conductive layer are made of polyethylene or polyvinyl chloride. This completes the cable production process. After the finished product is inspected, it is packaged and put into storage.
[0019] Preferably, the insulated wire core is manufactured through a VCV cross-linking production line, and is degassed in a degassing chamber before being wrapped with a water-blocking buffer layer.
[0020] The production process of the copper wire water-blocking layer includes: drawing copper wire to the required diameter using a wire drawing machine, wrapping water-blocking tape around the copper wire at equal intervals, and flattening the copper wire at equal intervals using a roller press to form the flat copper wire.
[0021] The beneficial effects of this invention are:
[0022] By adding a copper wire water-blocking layer in the gap between the aluminum sheath and the water-blocking buffer layer of the cable, the contact part within the crimped section changes from the original water-blocking buffer layer and aluminum sheath to a water-blocking buffer layer, flat copper wire, and aluminum sheath. Copper wire has stronger electrical resistance and thermal conductivity than aluminum, improving the contact performance between the aluminum sheath and the water-blocking buffer layer. The copper wire water-blocking layer prevents electrochemical reactions between the aluminum sheath and the water-blocking buffer layer, reducing their contact resistance. Furthermore, copper does not react with the water-blocking buffer layer to generate white powder. The addition of the copper wire water-blocking layer also overcomes the problem of poor water-blocking effect caused by the gap, especially at the crest of the gap, being too far from the water-blocking buffer layer, thus improving the longitudinal water-blocking performance of the cable. In addition, the flat copper wire is bent at the crimped section of the aluminum sheath, which does not affect the cable's original bending performance. The copper wire can also quickly transfer heat from this area to other locations, reducing the probability of heat accumulation and ablation in the high-voltage cable's water-blocking buffer layer.
[0023] The water-blocking corrugated aluminum sheathed high-voltage cable of the present invention has a simple structure. Its position in the gap can be controlled by simply adjusting the laying position and tension of the copper wire water-blocking layer. The structure or specifications of the round copper wire and flat copper wire can be flexibly adjusted according to design requirements, rolling depth, water-blocking material and other design parameters to ensure that the copper wire is always in the optimal position. Attached Figure Description
[0024] Figure 1 This is an internal structural diagram of a specific embodiment of the water-blocking corrugated aluminum sheathed high-voltage cable of the present invention;
[0025] Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle;
[0026] Figure 3 This is a schematic diagram of the welding and rolling process of the water-blocking corrugated aluminum sheathed high-voltage cable of the present invention;
[0027] Figure 4 This is a schematic diagram of the welding position of the water-blocking corrugated aluminum sheathed high-voltage cable of the present invention;
[0028] Figure 5 This is a flowchart of the production method of the water-blocking corrugated aluminum sheathed high-voltage cable of the present invention.
[0029] In the above attached figures: 1. Aluminum sheath; 2. Copper wire water-blocking layer; 21. Round copper wire; 22. Flat copper wire; 23. Water-blocking tape; 3. Water-blocking buffer layer; 4. Insulated wire core; 41. Conductor layer; 42. Insulation layer; 5. Adjustable reel; 6. Rolling knife; 71. Welding point; 72. Weld seam; 73. Welding gun. Detailed Implementation
[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific way. Therefore, they should not be construed as limiting the present invention.
[0031] like Figure 1 and Figure 2 As shown, this invention provides a water-blocking corrugated aluminum-sheathed high-voltage cable, including a water-blocking buffer layer 3. The outer side of the water-blocking buffer layer 3 is an aluminum sheath 1 with spiral grooves. A copper wire water-blocking layer 2 is provided between the aluminum sheath 1 and the water-blocking buffer layer 3. The copper wire water-blocking layer 2 includes round copper wires 21 and flat copper wires 22 arranged sequentially. The flat copper wires 22 are located at the grooves of the aluminum sheath 1. The round copper wires 21 and flat copper wires 22 are naturally connected and appear continuously at intervals. Furthermore, a water-blocking tape 23 is provided over the round copper wires 21. The water-blocking tape 23 can be water-blocking yarn, i.e., water-blocking yarn loosely wound on the copper wires. The thickness of the water-blocking tape 23 is 1.2–1.8 mm, preferably 1.5 mm. Since the copper wires are close to the corrugated aluminum sheath, the expansion volume of the water-blocking tape 23 is generally more than twice the thickness of the tape. A 1.5 mm thickness balances water-blocking performance and material consumption. The length of the round copper wire 21 is 2 to 5 times the length of the flat copper wire 22, preferably 3 times, and the ratio can also be adjusted according to the depth of the rolled pattern.
[0032] Meanwhile, the flat copper wire 22 is a bare copper wire. The water-blocking strip 23 on the flat copper wire 22 is peeled off, forming a section of round copper wire 21 with a copper wire water-blocking layer 2 consisting of the water-blocking strip 23 and the bare flat copper wire 22. This design allows the round copper wire 21 to bend more effectively to support the expansion of the water-blocking strip 23. The flat copper wire 22, after being rolled, has a larger contact area with the water-blocking buffer layer 3, improving thermal and electrical conductivity in this area. The larger surface area also prevents the round copper wire 21 from easily embedding into the water-blocking buffer layer 3. Furthermore, the rougher surface after rolling increases surface friction, preventing slippage of the flat copper wire 22 and allowing it to bend precisely at the rolled area. The selected copper wire generally has a tensile strength of 250–380 MPa and is in a non-annealed state to ensure sufficient support within the gap.
[0033] In the above embodiments, by adding a copper wire water-blocking layer 2 in the gap between the aluminum sheath 1 and the water-blocking buffer layer 3 of the cable, the contact part within the groove changes from the original water-blocking buffer layer 3 and aluminum sheath 1 to the water-blocking buffer layer 3, flat copper wire 22, and aluminum sheath 1. Copper wire has stronger electrical resistance and thermal conductivity than aluminum, which improves the contact performance between the aluminum sheath 1 and the water-blocking buffer layer 3. The copper wire water-blocking layer 2 can prevent electrochemical reactions between the aluminum sheath 1 and the water-blocking buffer layer 3, reducing their contact resistance. Simultaneously, copper and the water-blocking buffer layer 3 will not undergo an electrochemical reaction to generate white powder. Furthermore, the addition of the copper wire water-blocking layer 2 overcomes the problem of poor water-blocking effect caused by the gap, especially the gap crest, being too far from the water-blocking buffer layer 3, thus improving the longitudinal water-blocking performance of the cable. In addition, the flat copper wire 22 is bent at the groove of the aluminum sheath 1, which does not affect the original bending performance of the cable. The copper wire can also quickly transfer heat from this area to other locations, reducing the probability of heat accumulation and ablation of the high-voltage cable's water-blocking buffer layer 3.
[0034] The water-blocking corrugated aluminum sheathed high-voltage cable of the present invention has a simple structure. Its position in the gap can be controlled by simply adjusting the laying position and laying tension of the copper wire water-blocking layer 2. The structure or specifications of the round copper wire 21 and the flat copper wire 22 can be flexibly adjusted according to design requirements, rolling depth, water-blocking material and other design parameters to ensure that the copper wire is always in the optimal position.
[0035] The water-blocking corrugated aluminum-sheathed high-voltage cable provided by this invention further includes an insulated core 4, which comprises a conductor layer 41 and an insulation layer 42, with a water-blocking buffer layer 3 outside the insulation layer 42. The conductor layer 41 is formed into a cylindrical shape by stranding copper or aluminum wire, and the conductor layer 41 has a semi-conductive material on its exterior; the insulation layer 42 is formed by extruding cross-linked polyethylene material and semi-conductive material around the conductor layer 41; the water-blocking buffer layer 3 comprises a semi-conductive non-woven fabric and a semi-conductive fluffy cotton, with water-blocking powder filling the space between the semi-conductive non-woven fabric and the semi-conductive fluffy cotton.
[0036] like Figure 5 As shown, the present invention also provides a method for producing a water-blocking corrugated aluminum sheathed high-voltage cable, which includes the following steps:
[0037] 1) Produce the copper wire water-blocking layer 2, the insulated wire core 4 and the aluminum sheath 1 respectively, and wrap the water-blocking tape 23 around the insulated wire core 4 to form a water-blocking buffer layer 3. The water-blocking buffer layer 3 is formed by wrapping the water-blocking buffer tape through a wrapping machine. Generally, about 3 layers are wrapped. Two methods can be selected: overlapping wrapping and gap wrapping.
[0038] 2) Aluminum sheath 1 longitudinally wraps insulated wire core 4 and water-blocking buffer layer 3: The insulated wire core 4 wrapped with water-blocking buffer layer 3 is fed into aluminum sheath 1, and the copper wire water-blocking layer 2 is guided into the space between water-blocking buffer layer 3 and aluminum sheath 1 by adjustable wire feeding wheel 5; In addition to adjusting the wire feeding position of copper wire water-blocking layer 2, adjustable wire feeding wheel 5 can also control its wire feeding tension. The wire feeding tension is controlled by adjusting the ratio of wire feeding speed of adjustable wire feeding wheel 5 to wire feeding speed of conductor. By adjusting these two parameters, the degree of bending of copper wire in the gap can be adjusted.
[0039] 3) The aluminum sheath 1 is welded into a cylindrical shape using an argon arc welding machine. Then, spiral grooves are rolled on the aluminum sheath 1 using a rolling cutter 6. The distance by which the rolling cutter 6 deforms the aluminum sheath 1 is greater than the gap between the aluminum sheath 1 and the water-blocking buffer layer 3. Therefore, the water-blocking buffer layer 3 will be deformed by compression, resulting in a depression at the contact area and a protrusion at the gap area. The copper wire water-blocking layer 2 is located between the buffer water-blocking layer and the wrinkled aluminum sheath 1 and is tightly fixed at the contact position. The round copper wire 21 with water-blocking strip 23 at the gap area will bend naturally due to the downward pressure of the rolling cutter 6.
[0040] 4) An outer sheath and a semi-conductive layer are extruded on the outside of the aluminum sheath 1. The outer sheath and the semi-conductive layer are made of polyethylene or polyvinyl chloride. The cable production process is completed, and the finished product is packaged and put into storage after inspection.
[0041] In the above production steps, the insulated wire core 4 is completed through the VCV cross-linking production line and degassed in the degassing chamber, and then the water-blocking buffer layer 3 is wrapped around it; the production process of the copper wire water-blocking layer 2 includes: drawing the copper wire to the required diameter using a wire drawing machine, wrapping the water-blocking tape 23 around the copper wire at equal intervals, and flattening the copper wire into flat copper wire 22 at equal intervals using a roller press; the extrusion of the outer sheath and the extrusion of the semi-conductive layer can be carried out using a φ200 extruder and a φ120 extruder, respectively.
[0042] like Figure 3 and Figure 4 The diagram shows the welding and rolling process of the aluminum sheath 1. The water-blocking copper wire layer and the insulated core 4 are wrapped inside the aluminum sheath 1. The seam is welded using an argon arc welding torch 73. The positions of the welding point 71 and the weld seam 72 are shown in the diagram. Figure 4 As shown, the aluminum sheath 1 is then rolled into a spiral shape using a rolling cutter 6.
[0043] The following table shows the process parameters during the specific implementation:
[0044]
[0045]
[0046] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.
Claims
1. A water-blocking corrugated aluminum-sheathed high-voltage cable, characterized in that: It includes a water-blocking buffer layer (3), the outer side of which is an aluminum sheath (1) with spiral grooves, and a copper wire water-blocking layer (2) is provided between the aluminum sheath (1) and the water-blocking buffer layer (3); the copper wire water-blocking layer (2) includes round copper wire (21) and flat copper wire (22) arranged in sequence, the round copper wire (21) and the flat copper wire (22) are in a natural connection state and appear continuously at intervals, and the flat copper wire (22) is bent at the groove of the aluminum sheath (1).
2. The water-blocking corrugated aluminum-sheathed high-voltage cable as described in claim 1, characterized in that: The flat copper wire (22) is a bare copper wire.
3. The water-blocking corrugated aluminum-sheathed high-voltage cable as described in claim 1, characterized in that: It also includes an insulated core (4), which includes a conductor layer (41) and an insulation layer (42), with the water-blocking buffer layer (3) outside the insulation layer (42).
4. The water-blocking corrugated aluminum-sheathed high-voltage cable as described in claim 3, characterized in that: The conductor layer (41) is formed into a cylinder by twisting copper or aluminum wires, and the conductor layer (41) has a semi-conductive material on the outside.
5. The water-blocking corrugated aluminum-sheathed high-voltage cable as described in claim 3, characterized in that: The insulating layer (42) is formed by extruding cross-linked polyethylene material and semi-conductive material around the conductor layer (41).
6. The water-blocking corrugated aluminum-sheathed high-voltage cable as described in claim 1, characterized in that: The water-blocking buffer layer (3) includes a semi-conductive non-woven fabric and a semi-conductive fluffy cotton, with water-blocking powder filling the space between the semi-conductive non-woven fabric and the semi-conductive fluffy cotton.
7. The water-blocking corrugated aluminum-sheathed high-voltage cable as described in claim 1, characterized in that: The length of the round copper wire (21) is 2 to 5 times the length of the flat copper wire (22).
8. The water-blocking corrugated aluminum-sheathed high-voltage cable as described in claim 1, characterized in that: The round copper wire (21) is covered with a water-blocking strip (23), and the thickness of the water-blocking strip (23) is 1.2 to 1.8 mm.
9. A method for producing a water-blocking corrugated aluminum-sheathed high-voltage cable, comprising the water-blocking corrugated aluminum-sheathed high-voltage cable as described in any one of claims 1 to 8, characterized in that: The steps include the following: 1) The copper wire water-blocking layer (2), the insulated wire core (4) and the aluminum sheath (1) are produced respectively, and a water-blocking buffer layer (3) is formed by wrapping a water-blocking tape (23) around the insulated wire core (4). 2) Aluminum sheath (1) longitudinally wrapped insulated wire core (4) and water-blocking buffer layer (3): The insulated wire core (4) wrapped with water-blocking buffer layer (3) is fed into the aluminum sheath (1), and the copper wire water-blocking layer (2) is guided into the space between the water-blocking buffer layer (3) and the aluminum sheath (1) by the adjustable wire feeding wheel (5). 3) Weld the aluminum sheath (1) into a cylindrical shape, and then roll spiral grooves on the aluminum sheath (1) with a rolling cutter (6), and the distance of the deformation of the aluminum sheath (1) by the rolling cutter (6) is greater than the gap between the aluminum sheath (1) and the water-blocking buffer layer (3). 4) An outer protective layer and a semi-conductive layer are extruded on the aluminum sheath (1).
10. The method for producing a water-blocking corrugated aluminum-sheathed high-voltage cable as described in claim 9, characterized in that: The insulated wire core (4) is completed by the VCV cross-linking production line and degassed in the degassing chamber, and then wrapped with the water-blocking buffer layer (3). The production process of the copper wire water-blocking layer (2) includes: drawing the copper wire to the required diameter using a wire drawing machine, wrapping the water-blocking tape (23) around the copper wire at equal intervals, and flattening the copper wire at equal intervals using a roller press to form flat copper wire (22).