Conductor broken wire repairing method for copper-aluminum flexible transition submarine cable

Abstract

The invention discloses a conductor broken wire repairing method for a copper-aluminum flexible transition submarine cable, and belongs to the technical field of electrical engineering. The method sequentially comprises the steps of removing tension and straightening a conductor, taking a wire, fixing broken wires on the two sides of a body, taking a repairing monofilament, performing compression joint on the repairing monofilament, polishing a repairing compression joint point, filling the wire, fixing a filling wire part, welding a copper-aluminum repairing monofilament and the body, polishing a hot welding point, cleaning a conductor repairing position, measuring the outer diameter, repairing a wrapping tape and completing broken wire repairing of the copper-aluminum flexible transition conductor. According to the invention, the problem that the copper-aluminum welding part is easy to break in the production and operation processes is solved, so that the performance of the copper-aluminum flexible transition submarine cable conductor is improved, and the service life of the copper-aluminum flexible transition submarine cable conductor is prolonged.

Description

Technical Field

[0001] The present invention relates to a method for repairing broken filaments of a conductor of a copper-aluminum flexible transition submarine cable, belonging to the technical field of electrical engineering. Background Art

[0002] With the development of the copper-aluminum transition technology, copper-aluminum flexible transition conductors have been widely used in power transmission and distribution systems. However, during the production and operation processes, due to the different physical properties of copper and aluminum, the copper-aluminum welded joints are prone to fracture, affecting the performance and service life of the conductors.

[0003] For the problem of single-filament fracture of copper-aluminum flexible transition conductors during production and operation, the existing technical means lack effective solutions. Once the copper-aluminum welded joint of a copper-aluminum flexible transition conductor breaks, it is often necessary to replace the entire section of the conductor for repair. This not only has high costs but also complex operations, which will have a greater impact on the normal operation of the power system.

[0004] However, for the conductor after adopting the above repair method, it is difficult to guarantee the mechanical strength and stability. During subsequent use, the repaired part is prone to fracture or other failures again, unable to meet the requirements of long-term stable operation. Summary of the Invention

[0005] The purpose of the present invention is to address the deficiencies of the above existing technologies and provide a method for repairing broken filaments of a conductor of a copper-aluminum flexible transition submarine cable, aiming to solve the problem that the copper-aluminum welded joints are prone to fracture during production and operation, thereby improving the performance and service life of the conductor of the copper-aluminum flexible transition submarine cable.

[0006] To achieve the above purpose, the technical solution of the present invention is as follows: A method for repairing broken filaments of a conductor of a copper-aluminum flexible transition submarine cable, characterized by successively including: removing tension and straightening the conductor, taking filaments, fixing the broken filaments on both sides of the body, taking repair single filaments, crimping the repair single filaments, grinding the cold-welded crimping points of the repair, filling filaments, fixing the filled filament part, welding the copper-aluminum repair single filaments to the body, grinding the hot-welded joints, cleaning the repaired part of the conductor, measuring the outer diameter, and repairing the tape, to complete the repair of the broken filaments of the copper-aluminum flexible transition conductor.

[0007] The above method for repairing broken filaments of a conductor of a copper-aluminum flexible transition submarine cable specifically includes the following steps: 1) Removing tension and straightening the conductor: Remove the tension on the conductor before repair and perform straightening operations.

[0008] During the production and operation process, copper-aluminum flexible transition conductors are often subjected to external forces. Before repairing the broken wires of the copper-aluminum flexible transition conductors, the tension on the conductors needs to be removed. Removing the tension is a pretreatment based on the characteristics of the copper-aluminum flexible transition conductors because this conductor is prone to deformation when subjected to external forces during the production and operation process, and the existence of residual stress will affect the subsequent repair effect. By removing the tension, problems such as the conductor deforming or breaking again after repair due to residual stress can be avoided.

[0009] At the same time, use mechanical straightening methods such as the three-point straightening method to straighten the conductor to ensure that the repaired area is flat, and require the position of the break point to be horizontal, providing good basic conditions for subsequent precise repair.

[0010] 2) Wire extraction: Starting from the break point of the copper-aluminum single wire, shear the aluminum single wire and the copper single wire respectively to both axial sides, and the shearing point and the single wires on both its radial sides (adjacent) are of the same material, ensuring that the surrounding of the welding area for subsequent thermal welding is all of the same material.

[0011] ① Determine the shearing point: After determining the break point of the copper-aluminum single wire of the conductor, shear the copper single wire at the break point to the threshold range where the same material (aluminum single wire) appears on both radial sides of this shearing point, and shear the aluminum single wire at the break point to the threshold range where the same material (copper single wire) appears on both radial sides of this shearing point.

[0012] That is: It is required that the copper single wire or aluminum single wire after being sheared on the conductor body is also the same material of copper single wire or aluminum single wire on both radial sides. This is to ensure that during the subsequent thermal welding process, the welding area and the surrounding of the welding area are all of the same material, and a stable metallurgical bond can be achieved at the welding interface, avoiding welding quality problems caused by material differences; ② Marking: After confirming the shearing point, make marks on the surface of the single wire; ③ Cutting: Spin out the broken copper single wire and aluminum single wire to both sides of the conductor respectively. Here, it is necessary to spin out 2 pitch distances to prevent excessive stress on the single wire from affecting its pitch. Use a hand-held cutting saw to cut horizontally at the marked position to ensure that the cross-section is flat without protrusions. At this time, two broken wires are obtained in the area to be repaired on the conductor body. Subsequently, wind the sheared single wires (i.e., the two broken wires) back onto the conductor body.

[0013] 3) Fix the broken wires on both sides of the body: Use a fixing band to fix the shearing points of the two broken wires on the conductor body.

[0014] Use a fixing band to fix the shearing point and expose the shearing point to prevent the broken wires from moving and loosening during subsequent operations. The fixing band should have a certain elasticity and viscosity, which can firmly fix the single wire without causing excessive damage to it.

[0015] 4) Select repair monofilaments: Select one copper monofilament and one aluminum monofilament from the deformed monofilaments after stranding of the same batch of conductors as repair monofilaments.

[0016] Select a section from the deformed copper monofilaments and deformed aluminum monofilaments after stranding of the same batch of conductors as repair monofilaments. After these deformed monofilaments go through the stranding process, their microscopic lattice structures have a high degree of consistency with that of the original conductor, and the grain size deviation is <5%; at the same time, due to a certain amount of deformation, they can better adapt to the repair site and avoid local stress concentration problems caused by material property differences.

[0017] 5) Crimp the repair monofilaments: Place the copper monofilament and aluminum monofilament used as repair monofilaments into the fixture of the welding machine for cold welding and crimping to obtain copper-aluminum repair monofilaments.

[0018] During cold welding and crimping, perform precise crimping operations, keep the pitch the same, and ensure the tight combination between the repair monofilaments and form a stable connection structure by controlling crimping parameters such as pressure, time, and temperature.

[0019] 6) Grind the cold welding and crimping points of the repair monofilaments: Grind the crimping points and the two sides of the welding area successively with sandpapers of 200 mesh, 400 mesh, and 600 mesh.

[0020] First, use a file to preliminarily grind the crimping points to remove surface burrs and protrusions, and then successively use sandpapers of 200 mesh, 400 mesh, and 600 mesh to finely grind the crimping points and the two sides of the welding area. The 200-mesh sandpaper is mainly used for cutting to remove the heat-affected zone of welding; the 400-mesh sandpaper further smooths the surface; the 600-mesh sandpaper can effectively inhibit the initiation of fatigue cracks, prevent cracking when the monofilaments are bent after repair to the greatest extent, make the solder joint surface smooth and flat, and meet the requirements of a high surface quality.

[0021] 7) Fill the filaments: Carefully fill the copper-aluminum repair monofilaments into the wire-deficient part according to the stranding pitch, and ensure that the two endpoints of the copper-aluminum repair monofilaments have the same material as the shearing points of the two broken wires on the conductor body.

[0022] If the distance of the wire-deficient part is too long, that is, the length of the copper-aluminum repair monofilament is long, such as when the length of the wire-deficient part ≥ 1000 mm, to ensure the pitch maintenance and operation convenience, the copper-aluminum repair monofilament can be divided into multiple short segments and filled into the wire-deficient part. Ensure that there is at least one short segment of copper monofilament and one short segment of aluminum monofilament (facilitating crimping to form copper-aluminum monofilaments). It is recommended that the length of each short segment does not exceed 500 mm. Then crimp all the short segments respectively, and then fill them into the wire-deficient part together. Such a design is for two reasons. One is that the short segments are more convenient to store, and the other is that the short segments are convenient to maintain the pitch during crimping.

[0023] Taking the length of the wire break part as 1500 mm as an example, the copper-aluminum repair single wire can be divided into three sections. Select a 500-mm short section of copper single wire, a 500-mm short section of aluminum single wire, and then select another 500-mm short section of copper or aluminum single wire. Then, cold-weld and press-connect all the short sections, and finally fill them into the wire break part of the conductor together.

[0024] During the wire filling process, it is necessary to ensure that the distance between the filled single wire and the body single wire is less than 1 mm to facilitate subsequent welding operations and ensure that the overall structure and performance of the conductor are not affected.

[0025] 8) Fix the wire filling part: Fix the wire filling repair section at certain intervals with fixing bands.

[0026] Fix the wire filling repair section (i.e., the area on the conductor where the copper-aluminum repair single wire is filled) every 100 mm with fixing bands to ensure that the filled copper-aluminum repair single wire has no protruding arching phenomenon. The tightening force of the fixing bands should be moderate, neither too loose to cause the single wire to loosen nor too tight to damage the single wire.

[0027] 9) Weld the copper-aluminum repair single wire to the body.

[0028] Use hot welding for welding. When using an argon arc welding machine, when welding the copper side, adjust the equipment to the DC gear and use a silver electrode. When welding the aluminum side, adjust the equipment to the AC gear and use an aluminum electrode, and adjust the power of the welding machine respectively. Finally, make the electrode fuse to form a firm metallurgical bond to ensure the welding quality and connect the copper-aluminum repair single wire with the two broken wires into one body.

[0029] 10) Grind the hot welding solder joints.

[0030] Use a file and sandpaper to grind the solder joints, repeating the previous cold welding and press-fitting grinding steps, that is: use a file to initially grind the hot welding solder joints to remove surface burrs and protrusions, and then use 200-mesh, 400-mesh, and 600-mesh sandpaper to grind the solder joints and the welded areas on both sides of them in turn to make their surfaces smoother and flatter, further improving the quality of the solder joints and the performance of the conductor.

[0031] 11) Clean the repaired part of the conductor.

[0032] Clean the repaired position with alcohol, wipe the aluminum (copper) powder clean, and avoid the adverse effects of residual metal powder on subsequent processes. The cleaning process should be thorough to ensure that there is no impurity residue on the surface of the conductor.

[0033] 12) Measure the outer diameter: Measure whether the outer diameter of the repaired conductor meets the process requirements.

[0034] Use a high-precision outer diameter measuring instrument to measure whether the outer diameter of the repaired conductor meets the process requirements. The measurement accuracy should reach ±0.01 mm to ensure that the dimensional accuracy of the conductor meets the requirements of power transmission.

[0035] 13) Repair tape wrapping: Rewrap the binding tape and polyester tape according to the conductor structure.

[0036] According to the structure and usage environment requirements of the conductor, rewrap the binding tape and polyester tape to increase the strength and stability of the repaired part. The binding tape should have high strength and corrosion resistance, while the polyester tape should have good insulation and protection properties. The combined use of the two can effectively protect the repaired part and extend the service life of the conductor.

[0037] Compared with the prior art, the present invention has the following advantages: 1. Effectively solve the fracture problem: The present invention can specifically solve the problem of single wire fracture (i.e., fracture at the copper-aluminum welding joint) that occurs during the production and operation of copper-aluminum flexible transition conductors. Through a series of operation steps and process technologies, effective repair of the fractured part is achieved, greatly improving the reliability and stability of the conductor, reducing power accidents and economic losses caused by conductor fracture, and enhancing the performance and service life of the conductor.

[0038] 2. Improve mechanical strength and stability 2.1 Innovation in pretreatment process: Through the pretreatment steps of relieving tension and straightening the conductor, using a hydraulic release device to relieve tension and a three-point straightening method to straighten the conductor, the influence of residual stress generated by the deformation of the flexible conductor on the welding quality can be effectively eliminated. Verified by experiments, the geometric accuracy error of the repaired area ≤ 0.1 mm, avoiding the problem of secondary fracture caused by stress concentration in subsequent welding, providing a stable base for subsequent welding, and significantly improving the mechanical strength and stability of the repaired conductor.

[0039] 2.2 Precise selection of repair materials and optimization of process thresholds: In the wire taking step, it is strictly required to shear the single wire at the fracture point so that both the shear point and its radial sides are of the same material, and use the same batch of deformed single wires as the repair material. This selection can ensure the stability of the metallurgical bonding at the welding interface. The same material can avoid the risk of adjacent single wire fracture caused by different melting points, and the repaired copper-aluminum single wires are taken from the deformed material after the same batch of conductor stranding, and their microcrystalline lattice structure is highly consistent with the original conductor (grain size deviation < 5%), effectively avoiding local stress concentration caused by material property differences and further enhancing the mechanical strength and stability of the conductor.

[0040] 2.3 Application of dynamic filling and pitch synchronization technology: In the wire filling step, copper-aluminum repair single wires are filled according to the stranding pitch, and a segmented crimping compensation process is introduced. Through reasonable cutting and pre-crimping treatment of the copper-aluminum repair single wires, the pitch of the copper-aluminum repair single wires is made the same as that of the body, avoiding stress concentration and dimensional deformation problems caused by different pitches.

[0041] For long-distance wire break areas, the method of dividing the copper-aluminum repair single wires into multiple short segments and filling them into the wire break parts is adopted, which further ensures the pitch stability and the accuracy of the conductor size. Through actual testing, the outer diameter error of the repaired section of the conductor after filling is ≤0.2mm, effectively improving the overall quality and performance stability of the conductor.

[0042] 2.4 Grinding repair technology to improve surface quality: The solder joints and the solder areas on both sides are successively polished with 200-400-600 mesh sandpaper. The 200-400 mesh sandpaper removes the heat-affected zone of welding through cutting, and the 600 mesh sandpaper effectively inhibits the initiation of fatigue cracks, preventing cracking to the greatest extent when the single wire bends after repair, making the surface of the solder joint smooth and flat, meeting the requirements of high surface quality. This fine grinding repair technology not only improves the quality and reliability of the solder joint, but also enhances the wear resistance and corrosion resistance of the entire conductor, thus improving the mechanical strength and stability of the conductor. Brief description of the drawings

[0043] Figure 1 is the process flow block diagram of the present invention; Figure 2 is the partial enlarged view of the conductor after wire break repair of the present invention; In the figure: 1 conductor, 2 copper-aluminum repair single wire, 3 thermo-welded solder joint, 4 aluminum single wire, 5 copper single wire, 6 copper single wire, 7 copper wire break. Specific embodiments

[0044] A method for repairing wire breaks in a conductor of a copper-aluminum flexible transition submarine cable, as Figure 1 shown, includes the following steps: 1) Remove the tension and straighten the conductor During the production and operation process, the copper-aluminum flexible transition conductor is often subjected to external forces. Before repairing the wire breaks in the copper-aluminum flexible transition conductor, the tension on the conductor needs to be removed. In an embodiment of the present invention, a three-point straightening method is used to straighten the conductor, ensuring that the repair area is flat and providing good basic conditions for subsequent precise repair.

[0045] 2) Take wire ① Starting from the wire break point of the copper-aluminum single wire, cut the aluminum single wire and the copper single wire respectively towards both axial sides, and the single wires at the cutting point and on both sides (adjacent) in the radial direction are of the same material, ensuring that the surrounding of the welding area for subsequent thermo-welding is of the same material (such as Figure 2As shown, on both radial adjacent sides of the shear point of the copper broken wire 7 are copper single wires 5 and copper single wire 6 of the same material as it); ② After confirming the shear point, make marks on the surface of the single wire; ③ Spin out the broken copper single wire and aluminum single wire to both sides of the conductor respectively (in an embodiment of the present invention, 2 pitches need to be spun out here), and use a hand-held cutting saw to cut horizontally at the marked position to ensure that the cross-section is flat without protrusions. The area to be repaired of the conductor body obtains two broken wires (copper broken wire, aluminum broken wire), and then the two broken wires are wound back to the conductor body.

[0046] 3) Fix the broken wires on both sides of the body Use an elastic and sticky fixing band to fix the shear point and expose the shear point to prevent the broken wires from moving and loosening during subsequent operations.

[0047] 4) Select repair single wires Select one copper single wire and one aluminum single wire from the deformed single wires after stranding of the same batch of conductors as the repair single wires.

[0048] 5) Crimp the repair single wires Put the copper single wire and aluminum single wire used as the repair single wires into the welding machine fixture for cold welding and crimping to obtain copper-aluminum repair single wires. During cold welding and crimping, precise crimping operations are carried out to keep the pitch the same. By controlling the crimping parameters such as pressure, time, and temperature, etc., ensure that the repair single wires are closely combined to form a stable connection structure.

[0049] 6) Grind the cold welding and crimping points of the repair single wires In an embodiment of the present invention, first use a file to preliminarily grind the crimping point to remove the burrs and protrusions on the surface, and then use sandpapers of 200 meshes, 400 meshes, and 600 meshes in sequence to finely grind the crimping point and the welding areas on both sides of it.

[0050] 7) Fill the wires Carefully fill the copper-aluminum repair single wires into the wire-deficient part according to the stranding pitch, and ensure that the two end points of the copper-aluminum repair single wires are of the same material as the shear points of the two broken wires on the conductor body.

[0051] If the distance of the wire-deficient part is too long, that is, the length of the copper-aluminum repair single wire is long, such as when the length of the wire-deficient part ≥ 1000 mm, to ensure the pitch retention and the convenience of operation, the copper-aluminum repair single wire can be divided into multiple short segments and filled into the wire-deficient part. The length of each short segment is not more than 500 mm. After that, all the short segments are crimped respectively, and then filled into the wire-deficient part. In an embodiment of the present invention, taking the length of the wire-deficient part as 1500 mm as an example, select a 500-mm short segment of copper single wire and two 500-mm short segments of aluminum single wire, crimp the three short segments by cold welding, and finally fill them into the wire-deficient part of the conductor together.

[0052] During the wire filling process, ensure that the distance between the filled single wire and the body single wire is less than 1 mm to facilitate subsequent welding operations.

[0053] 8) Fix the wire filling part In an embodiment of the present invention, the area where the copper-aluminum repair single wire is supplemented on the conductor is tied and fixed every 100 mm with a fixing band to ensure that the filled copper-aluminum repair single wire has no protruding arching phenomenon.

[0054] 9) Weld the copper-aluminum repair single wire to the body In an embodiment of the present invention, hot welding is used. With an argon arc welding machine, when welding the copper side, the equipment is adjusted to the DC gear and a silver electrode is used. When welding the aluminum side, the equipment is adjusted to the AC gear and an aluminum electrode is used, and the power of the welding machine is adjusted respectively. Finally, the electrode is fused to connect the copper-aluminum repair single wire and the two broken wires into one body.

[0055] As Figure 2 shown, on both radial adjacent sides of the shear point of the copper broken wire 7 are the copper single wire 5 and the copper single wire 6 of the same material as it. After the copper side of the copper-aluminum repair single wire 2 and the shear point of the copper broken wire 7 are welded by hot welding, a hot welding solder joint 3 is formed.

[0056] 10) Grind the hot welding solder joint Use a file and sandpaper to grind the solder joint, repeating the previous cold welding crimping and grinding steps.

[0057] 11) Clean the conductor repair area Clean the repair position with alcohol, wipe off the aluminum (copper) powder, and ensure that there is no impurity residue on the surface of the conductor.

[0058] 12) Measure the outer diameter Use a high-precision outer diameter measuring instrument to measure whether the outer diameter of the repaired conductor meets the process requirements, and the measurement accuracy should reach ±0.01 mm.

[0059] 13) Repair the tape According to the conductor structure and usage environment requirements, re-wrap the binding tape and polyester tape to increase the strength and stability of the repair part.

Claims

1. A method for repairing broken wires of a conductor of a copper-aluminum flexible transition submarine cable, characterized in that, It includes the following steps: 1) Remove the tension on the conductor before repair and straighten the conductor; 2) Starting from the break points of the copper and aluminum single wires, cut the aluminum single wire and the copper single wire respectively to both axial sides, and the single wires at the cutting points and on both radial sides thereof are of the same material, and two broken wires are obtained in the area to be repaired of the conductor body; 3) Use a fixing band to fix the cutting points of the two broken wires on the conductor body and fix the two broken wires; 4) Select one copper single wire and one aluminum single wire from the deformed single wires as repair single wires; 5) Cold-weld and press the selected copper single wire and aluminum single wire as repair single wires to obtain a copper-aluminum repair single wire; 6) Grind the cold-welded and pressed joints of the repair single wires; 7) Fill the wire-missing part with the copper-aluminum repair single wire according to the lay length, and ensure that the two end points of the copper-aluminum repair single wire are of the same material as the cutting points of the two broken wires on the conductor body; 8) Fix the wire-filled repair section of the conductor with a fixing band at certain intervals; 9) Weld the copper-aluminum repair single wire and the conductor body by hot welding to restore the continuity at the break; 10) Grind the hot-welded joints; 11) Clean the repaired part of the conductor; 12) Measure whether the outer diameter of the repaired conductor meets the process requirements; 13) Rewind the tape according to the conductor structure to complete the repair of the broken wires of the copper-aluminum flexible transition conductor.

2. The conductor broken wire repair method of a copper-aluminum flexible transition submarine cable according to claim 1, characterized in that, In step 2): After confirming the cutting points, make marks on the surface of the single wires; then screw the broken copper single wire and aluminum single wire out of the conductor to both sides, and here it is necessary to screw out 2 times the lay length; then use a hand-held cutting saw to cut horizontally at the marked position, and then wind the cut single wires back to the conductor.

3. A method for repairing broken wires of a conductor of a copper-aluminum flexible transition submarine cable according to claim 1, characterized in that, In steps 3) and 8), the fixing band is an elastic and adhesive fixing band.

4. A method for repairing broken filaments of a conductor of a copper-aluminum flexible transition submarine cable according to claim 1, characterized in that, In step 4), select a section from the deformed copper single wires and deformed aluminum single wires after stranding of the same batch of conductors as the repair single wires.

5. A method for repairing broken filaments of a conductor of a copper-aluminum flexible transition submarine cable according to claim 1, characterized in that, In steps 6) and 10), after cold-welding and pressing or hot-welding, first use a file to preliminarily grind the welded joints, and then use sandpapers with 200 meshes, 400 meshes, and 600 meshes to grind the welded joints and the welded areas on both sides in sequence.

6. A method for repairing broken filaments of a conductor of a copper-aluminum flexible transition submarine cable according to claim 1, characterized in that, In step 7), when the length of the wire-missing part ≥ 1000 mm, divide the copper-aluminum repair single wire into multiple short sections and fill them into the wire-missing part, ensure that there is at least one short section of copper single wire and one short section of aluminum single wire, the length of each short section is not greater than 500 mm, then press all the short sections respectively, and then fill them into the wire-missing part together.

7. A method for repairing broken wires of a conductor of a copper-aluminum flexible transition submarine cable according to claim 6, characterized in that, In step 7), ensure that the distance between the filled single wires and the body single wires is less than 1 mm for welding operation.

8. A method for repairing broken filaments of a conductor of a copper-aluminum flexible transition submarine cable according to claim 1, characterized in that, In step 8), tie and fix the wire-filled repair section of the conductor with a fixing band every 100 mm.

9. A method for repairing broken wires of a conductor of a copper-aluminum flexible transition submarine cable according to claim 1, characterized in that, In step 9), use a tungsten argon arc welding machine for hot welding. When welding the copper side, adjust the equipment to the DC gear and use a silver electrode. When welding the aluminum side, adjust the equipment to the AC gear and use an aluminum electrode, and adjust the power of the welding machine respectively to finally make the electrode melt.

10. A method for repairing broken filaments of a conductor of a copper-aluminum flexible transition submarine cable according to claim 1, characterized in that, In step 11), wipe the repaired part of the conductor with alcohol.

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