A 300VT hybrid conductor and a stranding method

Abstract

This invention discloses a 300VT hybrid conductor and its stranding method, belonging to the field of conductor fabrication technology. It includes, from the inside out, a central layer, a first circular wire layer, a second circular wire layer, a third circular wire layer, and a shaped wire layer. The central layer consists of a single circular wire, the first circular wire layer consists of six circular wires, the second circular wire layer consists of twelve circular wires, the third circular wire layer consists of eighteen circular wires, and the shaped wire layer consists of twenty V-shaped wires. Each V-shaped wire has a V-shaped protrusion and a V-shaped indentation, and the twenty V-shaped wires are arranged in close contact around the outer side of the third circular wire layer. Through this invention, a hybrid conductor structure with an inner layer of circular wires and an outer layer of V-shaped wires is achieved, compressing the internal voids of the conductor and regularizing the outer perimeter contour. This reduces the internal voids of large-section conductors, improves conductor space utilization, and alleviates the problem of wavy outer perimeter contours after stranding large-section conductors.

Description

Technical Field

[0001] This invention relates to a 300VT hybrid wire conductor and a stranding method, belonging to the field of wire conductor preparation technology. Background Technology

[0002] With the continuous increase in power transmission capacity, medium-voltage and high-voltage cables place higher demands on conductor structures, especially in applications with large cross-section conductors. Conductors not only need to meet specified conductivity requirements but also need to consider cross-sectional utilization, roundness, stranding stability, and adaptability to subsequent insulation extrusion and cable laying processes. The 300VT hybrid conductor and stranding method are applicable to the field of wire and cable conductor manufacturing, primarily used for the forming and stranding of large cross-section copper conductors. In these applications, the tightness of the conductor structure, the interlayer fit, and the outer contour shape directly affect the manufacturing quality and performance of the finished cable.

[0003] Existing large-section conductors are typically manufactured using a method of layered stranding and compaction of circular single wires. The conductor consists of a central layer and multiple layers of stranded circular wires, with the outer layer formed into a near-circular conductor after compaction. However, existing technologies have several problems: after stranding large-section circular wires, significant gaps often remain within the conductor, and the outer contour is prone to wavy undulations, limiting the conductor's roundness and space utilization. While existing irregularly shaped single-wire conductors offer advantages in outer perimeter bonding, their manufacturing process requires high precision in single-wire forming, mold ratios, stranding arrangement, and compaction control. Inconsistent process parameters can lead to unstable single-wire forming, discontinuous outer layer arrangement, and insufficient interlayer bonding. Furthermore, the existing structure suffers from complex single-wire specification control, insufficient stranding stability, and inadequate outer layer shaping during continuous production of large-section conductors, affecting the dimensional consistency of the finished conductor and its adaptability to subsequent processing.

[0004] Therefore, there is an urgent need to provide a 300VT hybrid conductor and stranding method to solve the above problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a 300VT hybrid conductor and a stranding method, which solves the problems of easy gap generation, high process requirements, and complex single-wire specification control in large-area stranding.

[0006] The technical problem to be solved by this invention is achieved by the following technical solution: a 300VT hybrid conductor. It includes a central layer, a first circular line layer, a second circular line layer, a third circular line layer, and a shaped line layer arranged sequentially from the inside out. The central layer is composed of a single circular line, the first circular line layer is composed of six circular lines, the second circular line layer is composed of twelve circular lines, the third circular line layer is composed of eighteen circular lines, and the shaped line layer is composed of twenty V-shaped lines. The V-shaped lines have V-shaped protrusions and V-shaped depressions, and the twenty V-shaped lines are arranged in close contact with each other around the outer side of the third circular line layer.

[0007] Preferably, the two sides of the V-shaped line are arc-shaped edges.

[0008] Preferably, the V-shaped protrusions and V-shaped recesses of adjacent V-shaped lines in the profile layer fit together and conform to each other.

[0009] Preferably, the profile layer is continuously arranged circumferentially, and the outer periphery of the profile layer forms a continuous near-circular outline.

[0010] Preferably, the circular single wire is made of copper, and the V-shaped wire is made of copper.

[0011] A stranding method for a 300VT hybrid conductor, preferably comprising: S1. Circular wire drawing: The copper billet wire is drawn into a circular single wire through nine round dies; the diameters of the round dies are 6.587mm, 5.496mm, 4.627mm, 3.943mm, 3.391mm, 2.951mm, 2.682mm, 2.448mm, and 2.25mm respectively. S2, V-shaped wire drawing: The copper billet wire is drawn into a V-shaped wire through 6 passes of special-shaped dies. The apertures of the 6 passes of special-shaped dies are 7.32mm, 6.01mm, 5.01mm, 4.20mm, 3.57mm and 3.16mm respectively. S3. Layered twisting: The circular single wires are twisted in layers according to the structure of 1, 6, 12, 18 to form the central layer, the first circular wire layer, the second circular wire layer, and the third circular wire layer. After the twisting is completed, 20 V-shaped wires are twisted on the outside to form the shaped wire layer.

[0012] Preferably, in S1, the annealing voltage during round wire drawing is set to 43.15V, the drawing speed is not greater than 22m / s, and the take-up air pressure is 0.2MPa~0.3MPa.

[0013] Preferably, in S2, the annealing voltage during V-shaped wire drawing is set to 35.33V, the drawing speed is not greater than 13m / s, and the take-up air pressure is 0.2MPa~0.4MPa.

[0014] Preferably, in S2, the corners of the six irregular molds are kept consistent in the feed direction.

[0015] Preferably, In S3, the twisting directions of the first circular wire layer, the second circular wire layer, the third circular wire layer, and the shaped wire layer are right, left, right, and left respectively, and the center layer is set in parallel.

[0016] Preferably, in S3, the pitches of the first circular line layer, the second circular line layer, the third circular line layer, and the profile layer are 140mm, 250mm, 310mm, and 330mm, respectively.

[0017] Preferably, in S3, a clamping mold is provided between each layer, and the aperture of the clamping mold is 6.60mm±0.10mm, 11.00mm±0.10mm, 15.10mm±0.10mm, and 20.40mm±0.10mm respectively.

[0018] The beneficial effects of this invention are: This invention employs a hybrid conductor structure consisting of a central layer, a first circular wire layer, a second circular wire layer, a third circular wire layer, and a V-shaped wire layer arranged sequentially from the inside out. The inner layer is configured as a single circular wire, while the outer layer is configured as a V-shaped wire. This structure achieves compression of the internal voids and regularization of the outer perimeter profile. The central and inner circular wires provide stable support for the outer layer, while the outer V-shaped wires, through their close fit, fill the surrounding space, thereby reducing the internal voids of large-section conductors, improving conductor space utilization, and mitigating the problem of wavy outer perimeter profiles after large-section stranding.

[0019] This invention, through the design of V-shaped lines with V-shaped protrusions and concave depressions, and arc-shaped edges on both sides, ensures that adjacent V-shaped lines fit together seamlessly within the profile layer, achieving a continuous closed arrangement of outer layer single lines. This structure creates a stable circumferential fit within the profile layer, resulting in tighter fit between outer layer single lines, reducing discontinuities in outer layer arrangement, localized warping, and insufficient interlayer bonding, thereby improving the outer layer shaping effect and the roundness of the conductor's outer circumference.

[0020] This invention employs a layered stranding structure consisting of a center layer, a first round wire layer, a second round wire layer, a third round wire layer, and a profiled wire layer. By sequentially alternating right-hand, left-hand, right-hand, and left-hand stranding directions for the first, second, third, and profiled wire layers, reverse constraints and structural locking between layers are achieved. This structure ensures a more stable circumferential positional relationship between layers during continuous stranding, reducing loosening, misalignment, and structural fluctuations during continuous production of large-section conductors, and improving the dimensional consistency and stranding stability of the finished conductor.

[0021] This invention achieves sequential stranding, compaction, and shaping by setting the pitch of the first, second, third, and profiled wire layers in ascending order, and by setting corresponding compaction dies at the stranding exit of each layer. This structure ensures that each single wire completes contour shaping and gap compaction before entering the next stranding layer, reducing interlayer void accumulation, preventing insufficient outer layer shaping, and maintaining a continuous near-circular contour on the conductor's outer perimeter in the finished product state. This improves the stability and processing adaptability of subsequent insulation extrusion.

[0022] This invention establishes separate forming processes for round wire drawing and V-shaped wire drawing, allowing for independent shaping of round and V-shaped wires. Round wires are drawn using nine passes of circular dies, while V-shaped wires are drawn using six passes of shaped dies, achieving stable control over different wire specifications. This structure enables round and V-shaped wires to be formed within their respective suitable die paths, reducing problems such as unstable wire forming, cross-sectional offset, flipping, twisting, and surface damage. It also improves the consistency of wire specifications, providing a stable raw material foundation for subsequent stranding. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention.

[0024] Figure 2 This is a schematic diagram of the twisting process of the present invention.

[0025] In the diagram: 1-Central layer, 2-First circular layer, 3-Second circular layer, 4-Third circular layer, 5-Shaped layer. Detailed Implementation

[0026] To facilitate a clear understanding of the technical means, creative features, objectives, and effects of this invention, the invention will be further described below in conjunction with specific embodiments. Example 1

[0027] like Figures 1-2 As shown, a 300VT hybrid conductor and stranding method include, from the inside out, a center layer 1, a first round wire layer 2, a second round wire layer 3, a third round wire layer 4, and a shaped wire layer 5. The center layer 1 is composed of a single round wire, the first round wire layer 2 is composed of six round wires, the second round wire layer 3 is composed of twelve round wires, the third round wire layer 4 is composed of eighteen round wires, and the shaped wire layer 5 is composed of twenty V-shaped wires. The V-shaped wires have V-shaped protrusions and V-shaped indentations, and the twenty V-shaped wires are arranged in close contact with each other around the outer side of the third round wire layer 4.

[0028] The central layer 1 consists of a single circular wire located at the center of the cross-section, serving as the conductor's framework for positioning. The first circular layer 2 comprises six circular wires evenly arranged around the central layer 1, forming a tightly enclosing structure. The second circular layer 3 consists of twelve circular wires evenly distributed around the outer edge of the first circular layer 2, creating a stable interlayer support relationship. The third circular layer 4 consists of eighteen circular wires arranged around the outer edge of the second circular layer 3, further expanding the conductor cross-section and providing a supporting foundation for the outermost wire layer 5. Because the circular wires share similar or identical materials and processing conditions, the first, second, and third circular layers 2, 3, and 4 maintain good concentricity and support after stranding, ensuring a stable fit of the outer wire layer to the periphery.

[0029] The profile layer 5 consists of 20 V-shaped lines. Each V-shaped line has a V-shaped protrusion and a V-shaped recess, and both sides of the V-shaped line are arc-shaped, resulting in an overall V-shaped profile. The 20 V-shaped lines are arranged continuously circumferentially around the outer side of the third circular line layer 4. The V-shaped protrusions and recesses between adjacent V-shaped lines fit together, forming a continuous and closed circumferential fit in the outer layer. This fit allows the profile layer 5 to be further tightened into a circle after being placed around the outer side of the third circular line layer 4, forming a continuous near-circular structure on the outer perimeter. Because each V-shaped line has arc-shaped edges on both sides, the V-shaped lines have a good fit and transition when they come into contact with each other, reducing local sharp corner interference between layers, making the outer layer arrangement smoother, and also facilitating the maintenance of overall profile stability in subsequent pressing processes.

[0030] Each V-shaped wire in the shaping layer 5 is a single, irregularly shaped copper wire with an overall cross-section resembling a V-shape. When the 20 V-shaped wires are arranged continuously circumferentially around the outer side of the third circular wire layer 4, the V-shaped protrusions and concave areas between adjacent V-shaped wires interlock, forming a continuous circumferential fit. The arc-shaped edge of each V-shaped wire, in its adjacent arrangement, together with the arc-shaped edges of the surrounding V-shaped wires, defines the outer perimeter of the shaping layer 5, ensuring a stable arrangement after the shaping layer 5 is placed around the third circular wire layer 4, and creating a continuous near-circular structure on the outer perimeter. The third circular wire layer 4 consists of 18 circular single wires forming an outer support ring, providing circumferential support to the shaping layer 5, ensuring the V-shaped wires close stably along the outer perimeter during twisting, and preventing significant misalignment, warping, or excessively large gaps in the outer layer. In terms of materials, both the round single wires and the V-shaped wires are made of copper. The round single wires can be obtained by drawing oxygen-free copper rods, while the V-shaped wires can be obtained by drawing copper billets of the same material into irregular shapes, ensuring that each layer maintains consistency in conductivity. Because the inner layer is a round single wire and the outer layer is a V-shaped wire, the conductor forms a hybrid structure of "inner circle, outer irregular shape" in cross-section. The inner round wires are responsible for forming the basic supporting framework of the conductor, while the outer V-shaped wires are responsible for shaping and forming the outer perimeter contour. This structure facilitates stable layer-by-layer arrangement during stranding and also helps to further regularize the outer contour during compression.

[0031] In this embodiment, the circular single wire is prepared using a circular wire drawing process. Specifically, the copper billet wire is drawn sequentially through nine circular dies to form a circular single wire. The diameters of the nine circular dies are 6.587mm, 5.496mm, 4.627mm, 3.943mm, 3.391mm, 2.951mm, 2.682mm, 2.448mm, and 2.25mm, respectively. During the drawing process, the copper billet wire is drawn from the previous die and enters the next die, gradually reducing its diameter to obtain a circular single wire that meets the specifications. The annealing voltage is set to 43.15V, the drawing speed is no more than 22m / s, and the take-up air pressure is 0.2MPa~0.3MPa to ensure the circular single wire maintains a suitable processing state after drawing, facilitating subsequent stranding. In this embodiment, the circular single wire can be welded, with a welding distance of no less than 500mm, and the welding direction must be consistent.

[0032] The V-shaped wire is prepared using a V-shaped wire drawing process. Specifically, the copper billet wire is drawn sequentially through six shaped dies to form a V-shaped wire. The diameters of the six shaped dies are 7.32mm, 6.01mm, 5.01mm, 4.20mm, 3.57mm, and 3.16mm, respectively. The edges and corners of each shaped die are kept consistent in the wire feeding direction, ensuring that the copper billet wire maintains a uniform stress direction throughout the continuous drawing process, gradually reducing its surface area and forming its shape. This prevents the wire from flipping, twisting, or suffering surface damage during the forming process. During V-shaped wire drawing, the annealing voltage is set to 35.33V, the drawing speed is no more than 13m / s, and the take-up air pressure is 0.2MPa~0.4MPa, ensuring that the V-shaped wire remains in a suitable stranded state after the shaped wire is formed.

[0033] In this embodiment, the round wire drawing is completed using an LDD-450 / 11-2 type copper drawing machine. The copper billet enters the equipment from the inlet and is drawn sequentially through nine round dies to form a single round wire. The nine round dies are arranged in the diameter reduction sequence along the drawing path. After the copper billet undergoes initial reduction in cross-section at the previous die, it enters the next die for further shaping, gradually transitioning from a Φ8.00mm copper billet to a finished round single wire. During the drawing process, the round wire passes through each die sequentially, forming a continuous and uniform circular cross-section on the outer circumference of the wire, avoiding surface scratches and dimensional fluctuations caused by large-scale diameter reduction in a single step. After the round wire is formed, it undergoes annealing and winding control to maintain suitable flexibility and surface condition, facilitating subsequent stranding processes. The finished diameter of the round wire is controlled within the range of 2.20mm to 2.23mm, meeting the requirements of the central layer and each round wire layer.

[0034] In this embodiment, the V-shaped wire drawing is completed using a specialized shaped wire drawing die. The copper billet wire passes through six shaped dies sequentially from the inlet end, gradually transitioning from a circular cross-section to a V-shaped cross-section. The corners of the six shaped dies remain consistent in the inlet direction, and the guide edges, transition edges, and sizing edges of each die are arranged in the same direction, ensuring that the copper billet wire completes surface reduction and cross-section shaping under the same stress posture in each pass. When the copper billet wire enters the first shaped die, it undergoes preliminary shaping. Subsequently, the side contours, outer arc surfaces, and inner concave positions are gradually corrected in subsequent dies, ultimately forming the finished V-shaped wire. Due to the step-by-step forming method, the V-shaped wire maintains a continuous and stable deformation path during the drawing process, avoiding abnormalities such as flipping, twisting, corner cracking, surface scratches, or cross-section displacement. After the V-shaped wire is drawn, it undergoes annealing and winding control to ensure that the wire maintains the stability of its irregular cross-section while achieving a suitable stranding state. The equivalent wire diameter of the finished V-shaped wire is controlled within the range of 3.11mm to 3.12mm.

[0035] After the circular single wires and V-shaped wires are prepared, they enter the layer stranding process. During layer stranding, a central layer 1 is first formed with one circular single wire. Then, six circular single wires are stranded sequentially to form the first circular wire layer 2. Twelve circular single wires are stranded to form the second circular wire layer 3. Eighteen circular single wires are stranded to form the third circular wire layer 4. Finally, 20 V-shaped wires are stranded on the outside of the third circular wire layer 4 to form the shaped wire layer 5. During stranding, the stranding directions of the first circular wire layer 2, the second circular wire layer 3, the third circular wire layer 4, and the shaped wire layer 5 are right-handed, left-handed, right-handed, and left-handed, respectively. The central layer 1 is arranged in parallel, so that the layers form a relatively stable reverse constraint relationship after stranding. The pitches of the first round wire layer 2, the second round wire layer 3, the third round wire layer 4, and the profile layer 5 are 140mm, 250mm, 310mm, and 330mm respectively. The pitch gradually increases from the inside to the outside, so that each layer maintains a reasonable spiral propulsion relationship during the winding process and avoids the inner and outer layers from being squeezed too tightly or too loosely.

[0036] In this embodiment, the layered stranding is performed in a step-by-step manner. First, a single circular wire is formed into a central layer 1. Then, six circular wires are evenly stranded to form a first circular layer 2. Subsequently, twelve circular wires are evenly stranded to form a second circular layer 3. Then, eighteen circular wires are evenly stranded to form a third circular layer 4. Finally, twenty V-shaped wires are stranded around the third circular layer 4 to form a shaped wire layer 5. During the stranding process, the single wires of each layer are supplied by the corresponding wire feeder, guided into the stranding equipment by the guide device, and continuously advance along the axial direction. The central layer 1 remains parallel, and the outer layers unfold circumferentially around the inner layer. The stranding directions of the first circular layer 2, the second circular layer 3, the third circular layer 4, and the shaped wire layer 5 are right-handed, left-handed, right-handed, and left-handed, respectively. The directions of each layer are alternated to form a reverse constraint relationship between adjacent layers, reducing the tendency of the conductor to loosen during axial movement. The pitches of the first circular wire layer 2, the second circular wire layer 3, the third circular wire layer 4, and the profile layer 5 are 140mm, 250mm, 310mm, and 330mm respectively. The pitch gradually increases from the inside to the outside, so that each layer forms a stable spiral propulsion relationship during winding. This avoids excessive compression of the inner layer due to too small a pitch, and also avoids loosening and increased circumferential gaps in the outer layer due to too large a pitch.

[0037] During the layered stranding process, compaction dies are installed between each layer. These dies are located at the stranding exits of the first round wire layer 2, the second round wire layer 3, the third round wire layer 4, and the profiled wire layer 5, respectively. The diameter of the compaction die for the first round wire layer 2 is 6.60 mm ± 0.10 mm, for the second round wire layer 3 it is 11.00 mm ± 0.10 mm, for the third round wire layer 4 it is 15.10 mm ± 0.10 mm, and for the profiled wire layer 5 it is 20.40 mm ± 0.10 mm. As the stranded conductors pass through each compaction die, the outer periphery of each individual wire is radially constrained, the circumferential position between the individual wires is corrected, and the interlayer gaps are gradually compacted. The six circular lines in the first circular line layer 2 form a relatively stable ring arrangement after passing through the first pressing mold. The twelve circular lines in the second circular line layer 3 are further bonded after passing through the second pressing mold. The eighteen circular lines in the third circular line layer 4 form a continuous supporting outer contour after passing through the third pressing mold. The twenty V-shaped lines in the profile layer 5 are finally shaped after passing through the last pressing mold. The V-shaped protrusions and V-shaped depressions between adjacent V-shaped lines are further fitted together, and a continuous near-circular contour is formed on the outer periphery of the profile layer 5.

[0038] During the layered stranding process, compaction dies are installed between each layer. These dies are located at the stranding exits of the first round wire layer 2, the second round wire layer 3, the third round wire layer 4, and the profiled wire layer 5, respectively. The die apertures are 6.60mm±0.10mm, 11.00mm±0.10mm, 15.10mm±0.10mm, and 20.40mm±0.10mm, respectively. Each compaction die constrains the outer periphery of the stranded layers, ensuring that the individual wires in each layer complete contour shaping and gap compaction before entering the next layer of stranding. The first pressing die corresponds to the outer periphery of the first circular line layer 2, and slightly tightens the circumferential arrangement of the 6 circular single lines; the second pressing die corresponds to the outer periphery of the second circular line layer 3, and corrects the relative positions between the 12 circular single lines; the third pressing die corresponds to the outer periphery of the third circular line layer 4, and further refines the outer contour composed of 18 circular single lines; the fourth pressing die corresponds to the outer periphery of the profile layer 5, and finally shapes the mutual adhesion of the 20 V-shaped lines, so that the outer periphery of the profile layer 5 maintains a continuous near-circular contour.

[0039] In the manufacturing process of this embodiment, 20 V-shaped wires on the outer periphery of the V-shaped wire layer 5 are continuously arranged circumferentially. The V-shaped protrusions and concaves of adjacent V-shaped wires fit together to form a continuous closed structure on the outer layer. This closed structure cooperates with the outer periphery support of the third round wire layer 4, so that the conductor maintains a stable round shape after the layering, stranding and compression are completed. Because the wire layer 5 adopts an arc-shaped edge structure, the contact transition between the V-shaped wires is relatively smooth, and the outer periphery is less likely to form a significant stepped contour, which facilitates the subsequent insulation extrusion process.

[0040] After the stranding and compression of the profile layer 5 are completed, the 20 V-shaped wires form a continuous closed structure along the outer periphery of the third circular wire layer 4. The circumferential positioning of adjacent V-shaped wires is achieved through the interaction of V-shaped protrusions and concave depressions, ensuring stable and continuous contact between adjacent wires on the outer periphery. Because the V-shaped wires have curved edges on both sides, adjacent V-shaped wires form a smooth transition upon contact, avoiding sharp corners or protrusions on the outer periphery. Therefore, the outer periphery of the profile layer 5 maintains a continuous, near-circular shape. After the third circular wire layer 4 provides circumferential support to the profile layer 5, the profile layer 5 maintains a stable covering state in the conductor's running direction, reducing the likelihood of localized edge warping, loose outer layers, or fluctuations in the outer periphery, facilitating subsequent insulation extrusion processes.

[0041] In this embodiment, each layer of single wire undergoes surface inspection and specification screening before stranding to ensure that the surface of the single wire is free of obvious indentations, cracks, oxide scale, and burrs. During stranding, each single wire is fed by its corresponding pay-off frame, enters the stranding equipment via guide wheels, and then completes layer forming within the stranding machine. Round single wires and V-shaped wires are evenly distributed within their respective layers, and the conductors advance continuously along the axial direction. After the outermost layer of wires is formed, it is finally shaped by a compaction die. The 300VT hybrid conductor formed by the entire process has a clear hierarchical structure, a coherent manufacturing process, and a well-defined structural relationship, making it suitable for continuous production.

[0042] In this embodiment, each layer of single wire undergoes visual inspection and specification screening before entering the stranding equipment. The inspection includes checking for indentations, cracks, oxide scale, burrs, creases, and localized damage on the wire surface, and verifying that the wire diameter and cross-sectional dimensions meet the requirements of the corresponding process. During stranding, each single wire is independently fed by its corresponding pay-off frame. The pay-off process is controlled by a tension adjustment mechanism to ensure continuous, stable, and vibration-free stranding as each layer enters the stranding area. Guide wheels limit the direction of wire movement to prevent swaying or crossing during the wire feeding process. After stranding, the conductor is continuously conveyed axially, undergoes final shaping by various stages of compression dies, and the finished product undergoes visual and dimensional verification. After confirming the continuity of the layer structure, the regular arrangement, and the stability of the outer contour, it is then wound up.

[0043] A stranding method for a 300VT hybrid conductor, comprising: S1. Circular Wire Drawing. Copper billet wire is drawn into a circular single wire through nine round dies. The diameters of the nine round dies are 6.587mm, 5.496mm, 4.627mm, 3.943mm, 3.391mm, 2.951mm, 2.682mm, 2.448mm, and 2.25mm, respectively. The copper billet wire passes through each round die in the drawing equipment, with the diameter decreasing step by step to form a circular single wire. During circular wire drawing, the annealing voltage is set to 43.15V, the drawing speed is no more than 22m / s, and the take-up air pressure is 0.2MPa~0.3MPa. These process parameters are controlled to maintain the circular single wire in a suitable state for subsequent stranding.

[0044] S2. V-shaped wire drawing. The copper billet wire is drawn into a V-shape using six passes of shaped dies. The apertures of the six dies are 7.32mm, 6.01mm, 5.01mm, 4.20mm, 3.57mm, and 3.16mm, respectively. During the drawing process, the copper billet wire passes through each die sequentially, gradually transitioning from a circular shape to a V-shape. The edges of the six dies remain consistent in the wire-feeding direction, ensuring a uniform stress posture for the copper billet wire during each forming pass. During V-shaped wire drawing, the annealing voltage is set to 35.33V, the drawing speed is no more than 13m / s, and the take-up air pressure is 0.2MPa~0.4MPa. By controlling these process parameters, the V-shaped wire can be stably formed and meet the requirements for subsequent stranding.

[0045] S3. Layered Twisting. The circular single wires obtained in S1 are twisted in layers according to a structure of 1, 6, 12, and 18, first forming a central layer 1, a first circular wire layer 2, a second circular wire layer 3, and a third circular wire layer 4. Then, 20 V-shaped wires are twisted around the outside of the third circular wire layer 4 to form a shaped wire layer 5. During the twisting process, the twisting directions of the first circular wire layer 2, the second circular wire layer 3, the third circular wire layer 4, and the shaped wire layer 5 are right-handed, left-handed, right-handed, and left-handed, respectively, with the central layer 1 arranged in parallel. The pitches of the first circular wire layer 2, the second circular wire layer 3, the third circular wire layer 4, and the shaped wire layer 5 are 140mm, 250mm, 310mm, and 330mm, respectively. A clamping die is set between each layer, with the die apertures being 6.60mm±0.10mm, 11.00mm±0.10mm, 15.10mm±0.10mm, and 20.40mm±0.10mm, respectively. By using layered stranding and a compacting die, the individual wires in each layer maintain a stable interlayer positional relationship after stranding.

[0046] In process S3, 20 V-shaped wires are continuously arranged circumferentially along the outer side of the third circular wire layer 4. The V-shaped protrusions and concaves of adjacent V-shaped wires fit together, and the wire layer 5 surrounds the outer periphery of the third circular wire layer 4 to form a continuous near-circular outline. After stranding, the individual wires in each layer are compacted by a compression mold to ensure that the conductor structure remains coaxial and layered, and the wire layer 5 and the third circular wire layer 4 form a stable fit.

[0047] The manufacturing process in this embodiment adopts a process route of first drawing wire and then stranding. The round single wires and V-shaped wires are formed independently before being combined and stranded, which can ensure the consistency of specifications and forming stability of each layer of single wires. The finished conductor is composed of a center layer 1, a first round wire layer 2, a second round wire layer 3, a third round wire layer 4, and a shaped wire layer 5 in sequence. The product structure and stranding method correspond to each other and are suitable for continuous manufacturing.

[0048] In this embodiment, after the finished conductor is stranded and compressed, it undergoes outer diameter testing, cross-sectional area testing, surface quality testing, and electrical performance testing. For outer diameter testing, an outer diameter measuring device is used to measure at multiple points along the conductor's length to check if the finished outer diameter is stable within a predetermined range. For cross-sectional area testing, a cross-section of the conductor sample is cut to observe the arrangement of the center layer 1, the first round wire layer 2, the second round wire layer 3, the third round wire layer 4, and the V-shaped wire layer 5. It is checked whether the 20 V-shaped wires are continuously and seamlessly aligned circumferentially, and whether the V-shaped protrusions and concave areas of adjacent V-shaped wires maintain a proper fit. For surface quality testing, the outer surface of the conductor is checked for burrs, dents, skipped wires, missing wires, oxidation discoloration, and surface ridges. For electrical performance testing, the conductor's DC resistance at 20°C is measured, and the finished product weight is calculated to confirm that the product meets the corresponding specifications. After passing the tests, the conductor is wound onto a reel to form a 300VT hybrid wire conductor product.

[0049] In this embodiment, the fill factor is 0.96-0.98, and the weight per meter is 2611 kg / km.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention, all of which fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A 300VT hybrid conductor, characterized in that: It includes a central layer, a first circular line layer, a second circular line layer, a third circular line layer, and a shaped line layer arranged sequentially from the inside out. The central layer is composed of a single circular line, the first circular line layer is composed of six circular lines, the second circular line layer is composed of twelve circular lines, the third circular line layer is composed of eighteen circular lines, and the shaped line layer is composed of twenty V-shaped lines. The V-shaped lines have V-shaped protrusions and V-shaped depressions, and the twenty V-shaped lines are arranged in close contact with each other around the outer side of the third circular line layer.

2. The 300VT hybrid conductor according to claim 1, characterized in that: The V-shaped line has curved edges on both sides.

3. A 300VT hybrid conductor according to claim 2, characterized in that: The V-shaped protrusions and V-shaped recesses of adjacent V-shaped lines in the profile layer fit together and adhere to each other.

4. A 300VT hybrid conductor according to claim 3, characterized in that: The profile layer is continuously arranged circumferentially, and the outer periphery of the profile layer forms a continuous near-circular outline.

5. A 300VT hybrid conductor according to claim 1, characterized in that: The circular single wire is made of copper, and the V-shaped wire is made of copper.

6. A stranding method for a 300VT hybrid conductor, characterized in that: For manufacturing a 300VT hybrid wire conductor as described in any one of claims 1-5, comprising: S1. Circular wire drawing: The copper billet wire is drawn into a circular single wire through nine round dies; the diameters of the round dies are 6.587mm, 5.496mm, 4.627mm, 3.943mm, 3.391mm, 2.951mm, 2.682mm, 2.448mm, and 2.25mm respectively. S2, V-shaped wire drawing: The copper billet wire is drawn into a V-shaped wire through 6 passes of special-shaped dies. The apertures of the 6 passes of special-shaped dies are 7.32mm, 6.01mm, 5.01mm, 4.20mm, 3.57mm and 3.16mm respectively. S3. Layered twisting: The circular single wires are twisted in layers according to the structure of 1, 6, 12, 18 to form the central layer, the first circular wire layer, the second circular wire layer, and the third circular wire layer. After the twisting is completed, 20 V-shaped wires are twisted on the outside to form the shaped wire layer.

7. The stranding method for a 300VT hybrid conductor according to claim 6, characterized in that: In S1, the annealing voltage for drawing round wire is set to 43.15V, the drawing speed is no more than 22m / s, and the take-up air pressure is 0.2MPa~0.3MPa.

8. The stranding method for a 300VT hybrid conductor according to claim 6, characterized in that: In S2, the annealing voltage for drawing V-shaped wire is set to 35.33V, the drawing speed is no more than 13m / s, and the take-up air pressure is 0.2MPa~0.4MPa.

9. The stranding method for a 300VT hybrid conductor according to claim 6, characterized in that: In S2, the corners of the six irregular molds remain consistent in the feed direction.

10. A stranding method for a 300VT hybrid conductor according to claim 6, characterized in that: In S3, the twisting directions of the first circular wire layer, the second circular wire layer, the third circular wire layer, and the shaped wire layer are right, left, right, and left respectively, and the center layer is set in parallel.

11. The stranding method for a 300VT hybrid conductor according to claim 10, characterized in that: In S3, the pitches of the first circular line layer, the second circular line layer, the third circular line layer, and the profile layer are 140mm, 250mm, 310mm, and 330mm, respectively.

12. The stranding method for a 300VT hybrid conductor according to claim 6, characterized in that: In S3, a clamping mold is provided between each layer, and the aperture of the clamping mold is 6.60mm±0.10mm, 11.00mm±0.10mm, 15.10mm±0.10mm, and 20.40mm±0.10mm respectively.

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