Molded wire composite stranded copper conductor and medium-voltage power cable comprising same

Abstract

The utility model belongs to the technical field of cables, and particularly relates to a molded wire composite stranded copper conductor and a molded wire copper core composite stranded medium-voltage power cable. The molded line composite stranded copper conductor comprises an inner-layer copper conductor which is formed by pressing and stranding circular annealed copper single wires in a layered manner and an outer-layer copper conductor which is formed by pressing and stranding special-shaped annealed copper single wires in a layered manner. The molded wire copper core composite stranded medium-voltage power cable sequentially comprises molded wire composite stranded copper conductors, a semi-conductive conductor shielding layer, a crosslinked polyethylene insulating layer, an extruded semi-conductive insulating shielding layer, a metal shielding layer, a wrapping tape and an outer sheath from inside to outside. The twisting gap of the outer layer copper conductor is extremely small, so that the shielding embedding risk of the conductor is reduced; by using a slight pressing structure of the inner-layer conductor, the problem that a gap is formed between the outer-layer molded line and the inner-layer conductor due to the fact that the twisting outer diameter of the inner conductor is reduced is solved, and the stability of the twisting structure is kept; the diameter of a single line is adjustable, and cost reduction is facilitated; and the cross section of the conductor can be reduced by 1-2% under the condition of reaching the same direct-current resistance of the conductor.

Description

Technical Field

[0001] The utility model belongs to the technical field of cables, and in particular relates to a wire copper core composite stranded medium-voltage power cable. Background Art

[0002] The copper core medium voltage power cable conductor currently uses the compressed round second type copper conductor. The conductor is made of round single wires that are twisted and layered and compressed. However, after the metal is cold deformed, the DC resistance of the conductor will increase due to work hardening.

[0003] In order to save energy and reduce emissions, some cable factories try to apply shaped copper conductors to medium voltage power cables. Figure 1 (As shown) During the production process of compression deformation is small, the increase in the DC resistance of the conductor due to work hardening is small. Under the condition of achieving the same DC resistance of the conductor, the conductor cross-section can be reduced by about 1% to 2%, achieving the purpose of energy conservation and emission reduction. However, according to the provisions of "Table C.2 Maximum and minimum diameters of compressed stranded circular conductors of copper, aluminum and aluminum alloys" in GB / T3956-2008, 400mm is used. 2 For example, the minimum outer diameter of the conductor is 22.3mm, but the actual outer diameter of the stranded round copper conductor is 22.0mm, which does not meet the national standard. In addition, because the outer diameter is smaller than the national standard, it cannot be used with cable accessories or hardware, which brings great inconvenience and safety hazards to construction. Therefore, the stranded round copper conductor is rarely used.

[0004] Chinese patent (application number CN202220425611.0) proposes a composite stranded structure (such as Figure 2 As shown), 400mm 2For example, its inner conductor is made of round copper single wire with a nominal diameter of 2.79mm, twisted into 2 layers of 1+6+12. The diameter of the inner conductor is 2.79*5=13.95mm, and the outer layer is made of 2 layers of single wire twisted together. The final conductor outer diameter is 23.1mm. At this time, the outer diameter of the composite stranded copper conductor of the wire is consistent with the outer diameter of the second type of compact circular copper conductor, both of which are 23.1mm, meeting the requirements of "Table C.2 Maximum and minimum diameters of compacted stranded circular conductors of copper, aluminum and aluminum alloys" in GB / T3956-2008, so that the cable accessories and hardware used for cable installation can be fully matched with it. While achieving the same DC resistance of the conductor, the conductor cross-section can be reduced by about 1% to 2%, achieving the purpose of saving and reducing costs. However, the above patents also have the following technical problems: (1) In addition to the conductor, the materials that make up the cable also include conductor shielding, insulation, insulation shielding, copper tape, filling, armor, sheath, etc. The consumption of other materials will increase due to the large outer diameter of the conductor, thereby increasing the cost of the cable. In order to reduce the consumption of conductors while reducing the consumption of other materials, how to reduce the outer diameter of the conductor within the standard requirements has become a technical key.

[0005] (2) When the diameter of the round single wire of the inner conductor is reduced due to the drawing and stranding process, the inner conductor is a completely non-compact structure, which leads to a smaller final stranded outer diameter of the inner conductor, resulting in a gap between the outer wire and the inner conductor, causing the conductor stranded structure to be unstable and loose, resulting in the conductor being scrapped. Utility Model Content

[0006] The medium voltage power cable described in this application is a power cable with a rated voltage of 6kV to 35kV.

[0007] Taking into account the material cost and conductor stability issues, the utility model provides a copper core composite stranded medium voltage power cable with a profile. The technical solution is as follows:

[0008] A composite stranded copper conductor comprises an inner copper conductor and an outer copper conductor. The inner copper conductor is formed by compactly twisting 1 to 4 layers of round annealed copper wires of equal outer diameter; the outer copper conductor is formed by compactly twisting 1 to 4 layers of special-shaped annealed copper wires, each of which has a sector ring cross-section.

[0009] Preferably, the composite stranded copper conductor is 400 mm 2 The composite stranded copper conductor comprises an inner copper conductor and an outer copper conductor, wherein the inner copper conductor is formed by compactly twisting three layers of round annealed copper wires of equal outer diameter; and the outer copper conductor is formed by compactly twisting two layers of special-shaped annealed copper wires, wherein the cross-section of the special-shaped annealed copper wires is a sector ring.

[0010] The inner copper conductor is made of 19 round single wires with a diameter of 2.93mm, twisted and compressed in three layers according to the standard 1+6+12 method. Specifically, the first layer has one round single wire laid straight; the second layer has six round single wires twisted to the right with a twist pitch of 240mm-260mm, and then compressed using a twisting die with an inner diameter of 8.2mm; the third layer has 12 round single wires twisted to the left with a twist pitch of 370mm-390mm, and compressed again using a twisting die with an inner diameter of 13.4mm.

[0011] The outer copper conductor is formed by twisting 42 single wires in two layers in 18+24 degrees and pressing them tightly; 18 single wires are twisted in the right direction to form the secondary outer layer (1021) of the composite stranded copper conductor; the single wire fan length of the secondary outer layer (1021) is 3.05 mm, the height is 2.46 mm, the center angle is 20 degrees, and the minimum cross-section is 6.55 mm 2 The stranding pitch is 350mm-370mm, and the stranding die with an inner diameter of 17.9mm is used for compacting; 24 single wires are twisted in the left direction to form the outermost layer of the composite stranded copper conductor, and the fan length of the outermost layer (1022) of the single wire is 2.92mm, the height is 2.5mm, the central angle is 15°, and the minimum cross-section is 6.53mm 2 The stranding pitch is 320mm-340mm, and it is compacted using a compact stranding die with an inner diameter of 22.5mm.

[0012] Preferably, the composite stranded copper conductor is 400 mm 2 The composite stranded copper conductor comprises an inner copper conductor and an outer copper conductor, wherein the inner copper conductor is formed by compactly twisting three layers of round annealed copper wires of equal outer diameter; and the outer copper conductor is formed by compactly twisting two layers of special-shaped annealed copper wires, wherein the cross-section of the special-shaped annealed copper wires is a sector ring.

[0013] The inner copper conductor is made of 19 round single wires with a diameter of 3.00 mm, twisted in three layers according to a regular 1+6+12 stranding method. Specifically, the first layer has one round single wire laid straight; the second layer has six round single wires twisted to the right with a twist pitch of 240 mm to 260 mm, and then compressed using a twisting die with an inner diameter of 8.4 mm; the third layer has 12 round single wires twisted to the left with a twist pitch of 370 mm to 390 mm, and then compressed again using a twisting die with an inner diameter of 13.7 mm.

[0014] The outer copper conductor is formed by twisting 42 single wires in two layers in 18+24 degrees and pressing them tightly; 18 single wires are twisted in the right direction to form the secondary outer layer (1021) of the composite stranded copper conductor; the dimensions of the single wires in the secondary outer layer (1021) are as follows: the fan length is 3.15 mm, the height is 2.50 mm, the center angle is 20 degrees, and the minimum cross section is 6.92 mm 2 The stranding pitch is 360mm-380mm, and the stranding die with an inner diameter of 18.4mm is used for compaction. 24 single wires are twisted in the left direction to form the outermost layer of the composite stranded copper conductor. The outermost layer of single wires has a fan length of 3.00mm, a height of 2.55mm, a central angle of 15°, and a minimum cross-section of 6.90mm. 2 The stranding pitch is 320mm-340mm, and it is compacted using a compact stranding die with an inner diameter of 23.0mm.

[0015] A profiled copper core composite stranded medium voltage power cable comprises, from inside to outside, a profiled composite stranded copper conductor, a semi-conductive conductor shielding layer, a cross-linked polyethylene insulation layer, an extruded semi-conductive insulation shielding layer, a metal shielding layer, a wrapping tape, and an outer sheath.

[0016] Preferably, the metal shielding layer is obtained by wrapping a metal tape or a metal wire.

[0017] Preferably, when the profiled copper core composite stranded medium voltage power cable contains three profiled composite stranded copper conductors, each profiled composite stranded copper conductor and the semi-conductive conductor shielding layer, the cross-linked polyethylene (XLPE) insulation layer, and the extruded semi-conductive insulation shielding layer form an insulated core from the inside to the outside; a metal shielding layer is wrapped around the outside of the insulated core to form a metal shielded core; three identical metal shielded cores are twisted in the right direction to form a cable, the gaps in the twisted metal shielding cores are filled with filling material to make them round, and the twisted metal shielding cores are tightened by wrapping tape; and a layer of outer sheath is extruded outside the wrapping tape layer.

[0018] Further preferably, an isolation sleeve and an armor layer are sequentially arranged between the wrapping tape and the outer sheath from the inside to the outside.

[0019] More preferably, the armor layer is metal tape gap armor or metal wire armor.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The outer copper conductor is composed of 1 to 4 layers of an appropriate number of special-shaped annealed copper single wires slightly compressed and twisted. There is basically no twisting gap on the outer surface of the conductor, which reduces the risk of conductor shield embedding.

[0022] (2) The use of a slightly compressed structure for the inner conductor can keep the outer diameter of the inner conductor constant when the diameter of the round single wire is reduced within a reasonable range. This solves the problem of a gap between the outer wire and the inner conductor caused by the reduction of the twisted outer diameter of the inner conductor, and maintains the stability of the conductor twisting structure.

[0023] (3) The use of a slightly compressed structure for the inner conductor provides adjustable space for increasing or decreasing the diameter of the single wire. While ensuring that the outer diameter of the conductor remains unchanged, the conductor cross-section can be finely controlled based on the actual measurement of the DC resistance of the copper conductor, which is more conducive to the implementation of cost reduction.

[0024] (4) Composite stranded copper conductor, such as Figure 3 As shown in the figure, the inner layer is slightly compressed and twisted to achieve the purpose of diameter expansion, so that the outer diameter of the conductor meets the requirements of "Table C.2 Maximum and minimum diameters of compressed and stranded circular conductors of copper, aluminum and aluminum alloys" in GB / T 3956-2008, which solves the problem that the outer diameter of the wire conductor is small and cannot be used with cable accessories or hardware. The outer diameter of the conductor is smaller than the outer diameter of the conductor proposed in CN 202220425611.0 patent. In addition to reducing the cost of the conductor, the materials such as conductor shielding, insulation, insulation shielding, copper tape, filling, armoring, and sheath are also reduced due to the reduction in conductor diameter.

[0025] (5) The work hardening of the composite stranded copper conductor during the stranding process is minimal. While achieving the same conductor DC resistance, the conductor cross-section can be reduced by about 1% to 2%, which is in line with the national policy of energy conservation, environmental protection, and low carbon emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of a stranded circular copper conductor;

[0027] Figure 2 This is a schematic diagram of a composite twisted wire structure in the prior art;

[0028] Figure 3 This is a schematic structural diagram of the composite stranded copper conductor described in the present invention;

[0029] Figure 4 Schematic diagram of the structure of the composite stranded copper conductor described in Example 1;

[0030] Figure 5 Schematic diagram of the structure of the composite stranded copper conductor described in Example 2;

[0031] Figure 6 This is a structural schematic diagram of the copper core composite stranded medium voltage power cable described in Example 3.

[0032] Figure 7This is a schematic structural diagram of the copper core composite stranded medium voltage power cable described in Example 4.

[0033] Figure 8 This is a structural schematic diagram of the copper core composite stranded medium voltage power cable described in Example 5.

[0034] Figure 9 This is a structural schematic diagram of the copper core composite stranded medium voltage power cable described in Example 6.

[0035] Among them, 1. Type-wire composite stranded copper conductor; 101. Inner copper conductor; 102. Outer copper conductor; 1011. First layer; 1012. Second layer; 1013. Third layer; 1021. Second outer layer; 1022. Outermost layer; 2. Semi-conductive conductor shielding layer; 3. Cross-linked polyethylene insulation layer; 4. Extruded semi-conductive insulation shielding layer; 5. Metal shielding layer; 6. Filling material; 7. Tape; 8. Isolation sleeve; 9. Armor layer; 10. Outer sheath. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to specific embodiments. The advantages and features of the present invention will become clearer as the description proceeds. However, the embodiments are merely exemplary and do not limit the scope of the present invention in any way. It should be understood by those skilled in the art that the details and forms of the technical solutions of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, and such modifications and replacements shall fall within the scope of protection of the present invention.

[0037] Example 1

[0038] The DC resistance at 20℃ meets the requirements of GB / T 3956-2008, 400mm 2 The structural diagram of the composite stranded copper conductor 1 is as follows: Figure 4 As shown in , the technical solutions adopted are as follows:

[0039] (1) 400mm 2The composite stranded copper conductor 1 comprises an inner copper conductor 101 and an outer copper conductor 102. The inner copper conductor 101 is formed by twisting 19 round single wires with a diameter of 2.93 mm in three layers in a regular 1+6+12 pattern. The first layer 1011 comprises a single round wire laid straight; the second layer 1012 comprises six 2.93 mm round wires twisted in the right direction with a twist pitch of 240 mm to 260 mm. If the outer diameter of the innermost conductor strand is calculated as completely uncompressed, it is 2.93*3=8.79 mm. The stranding die selected is 8.2 mm, and the innermost copper conductor 101 has a slightly compressed structure. The third layer 1013 comprises twelve 2.93 mm round wires twisted in the left direction with a twist pitch of 370 mm to 390 mm. If the outer diameter of the twelve strands is calculated as completely uncompressed, it is 8.2+2.93*2=14.06 mm. The stranding die selected is 13.4 mm, and the inner copper conductor 101 has a slightly compressed structure. The advantages of using a slightly compressed structure are as follows:

[0040] (1.1) The use of a slightly compressed structure will not increase the work hardening of the conductor, and will not cause the problem of increased DC resistance of the conductor due to work hardening of the conductor.

[0041] (1.2) The slightly compressed structure makes the conductors tighter and prevents them from becoming loose.

[0042] (1.3) The slightly compressed structure makes the contact area between the inner round single wire layer and the outer profile layer larger, and the structure more stable.

[0043] (1.4) When the measured resistance margin is large, the single wire diameter can be reduced. When the measured resistance margin is small or unqualified, the single wire diameter can be increased. The use of a slightly compressed structure provides adjustable space for increasing or decreasing the single wire diameter without affecting the conductor stranding quality. If a completely non-compressed structure is used, the calculated outer diameter of 12 strands = 2.93*5 = 14.65mm. If the resistance margin is large at this time, the single wire diameter cannot be reduced because reducing the single wire diameter will cause the inner conductor diameter to decrease, resulting in a gap between the outer wire and the inner conductor, making the conductor stranding structure unstable and thus affecting the conductor stranding quality.

[0044] (2) The sub-outer layer 1021 of the composite stranded copper conductor is made of 18 right-hand stranded single wires with a stranding pitch of 350mm-370mm. Due to the twisting and the upper tolerance of the single wires, the gap between the single wires will become smaller, which will lead to the squeezing between the sub-outer layer 1021 single wires and the appearance of a gap between the inner conductor and the sub-outer layer 1021, resulting in poor twisting. Therefore, a gap needs to be left between each single wire. Since the twisting coefficient is 1.01, the positive tolerance of the single wire is controlled to be 1%d, so the comprehensive coefficient needs to be ≥1.01*1.01=1.02. Considering that the single wire may have a negative tolerance in actual production, the sub-outer layer 1021 needs to be slightly pressed when twisting to ensure the tightness of the twisted layer. After repeated tests, the dimensions of the single wire are as follows: the fan length is 3.05mm, the height is 2.46mm, the central angle is 20°, and the minimum cross-section is 6.55mm 2 Assuming no compression, the outer diameter of the 18 strands is calculated as 13.4 + 2.46 * 2 = 18.32 mm. The stranding die used in this case is 17.9 mm. The sub-outer layer of 1021 copper conductor is lightly compressed, allowing for tighter stranding and a more stable structure. The sector length of each strand is 3.05 mm. The circumference of the 18 strands along their 18.32 mm outer diameter is 18 * 3.05 = 54.9 mm. Before light compression, the outer circumference of the conductors is 18.32 * 3.14 = 57.5248 mm. The average gap ratio between each strand is 57.5248 / 54.9 = 1.0478, which is greater than 1.02, fully meeting actual production requirements. The remaining gaps are then tightened with light compression.

[0045] (3) The outermost layer 1022 is made of 24 shaped wires twisted in the left direction, with a twisting pitch of 320mm-340mm. Because the sub-outer layer 1021 is twisted with shaped single wires, the outer diameter is stable and the surface is flat. The shaped single wires of the outermost layer 1022 are twisted on the sub-outer layer 1021 and are relatively stable. In order to make the shaped wires of the outermost layer 1022 twisted without twisting gaps, thereby solving the problem of embedded conductor shielding, it is necessary to comprehensively consider the influence of the upper tolerance, lower tolerance and twisting coefficient of the shaped single wire on the twisting coefficient. At this time, the gap ratio between the shaped wires should be slightly less than or equal to the comprehensive gap ratio of the shaped single wire caused by twisting and the upper and lower tolerances of the shaped single wire, and after slight compression, the twisted layer is made tight and seamless.

[0046] Since the stranding coefficient is 1.023 and the positive tolerance of the single wire is 1%d, the comprehensive coefficient needs to be = 1.023*1.01=1.033. After repeated tests, the fan length is 2.92mm, the height is 2.5mm, the central angle is 15°, and the minimum cross-section is 6.53mm. 2, the outer diameter of the 24 strands is calculated as 17.9 + 2.5 * 2 = 22.9mm if it is not compressed at all. The stranding die selected at this time is 22.5mm. At this time, the outermost layer of 1022 copper conductor is a slightly compressed structure, which makes the conductor twisted more tightly. The fan length along the circumference of each wire is 2.92mm. The circumference of the 24 wires along the outer diameter of 22.9mm = 24 * 2.92 = 70.08mm. The 24 wires are twisted and slightly compressed before the conductor The outer circumference = 22.9*3.14 = 71.906mm, the average gap ratio between each wire = 71.906 / 70.08 = 1.026. At this time, if the tolerance problem of the single wire is considered, the average gap ratio between each wire = 1.026*1.01 = 1.03626, which is very close to the comprehensive coefficient of 1.033. At this time, after slight compression, a tightly twisted layer can be obtained, thereby solving the problem of embedded conductor shielding.

[0047] (4) The cross section of the composite stranded copper conductor 1 is 370 mm 2 ~374mm 2 , the conductor cross-section is reduced by about 1% to 2%, achieving the goal of energy saving and emission reduction.

[0048] (5) The outer diameter of the conductor of the composite stranded copper conductor 1 is 22.5 mm, which meets the requirements of "Table C.2 Maximum and minimum diameters of compressed stranded circular conductors of copper, aluminum and aluminum alloys" in GB / T3956-2008, and solves the problem that the outer diameter of the shaped wire conductor is small and cannot be used with cable accessories or hardware. In addition, the outer diameter of the conductor is smaller than the outer diameter of the conductor proposed in the patent "CN202220425611.0", which realizes that in addition to reducing the cost of the conductor, the materials such as conductor shielding, insulation, insulation shielding, copper tape, filling, armoring, and sheath are also reduced due to the reduction of the conductor diameter.

[0049] (6) The maximum DC resistance of the composite stranded copper conductor 1 at 20°C is 0.0470Ω / km.

[0050] Example 2

[0051] At 20℃, the DC resistance is better than 5% of that specified in GB / T 3956-2008, 400mm 2 The structural diagram of the composite stranded copper conductor 1 is as follows: Figure 5 As shown in , the technical solutions adopted are as follows:

[0052] (1) 400mm 2The composite stranded copper conductor 1 comprises an inner copper conductor 101 and an outer copper conductor 102. The inner copper conductor 101 is formed by twisting 19 round single wires with a diameter of 3.00 mm in three layers in a regular 1+6+12 pattern. The first layer 1011 comprises a single round wire laid straight. The second layer 1012 comprises six 3.00 mm round wires twisted in the right direction with a twist pitch of 240 mm to 260 mm. If the outer diameter of the innermost conductor strand is calculated as completely uncompressed, it is 3.00 x 3 = 9.0 mm. The stranding die selected is 8.4 mm. The innermost copper conductor 101 is now slightly compressed. The third layer 1013 comprises twelve 3.00 mm round wires twisted in the left direction with a twist pitch of 370 mm to 390 mm. If the outer diameter of the twelve strands is calculated as completely uncompressed, it is 8.4 + 3.00 x 2 = 14.4 mm. The stranding die selected is 13.7 mm. The inner copper conductor 101 is now slightly compressed. The advantages of using a slightly compressed structure are as follows:

[0053] (1.1) The use of a slightly compressed structure will not increase the work hardening of the conductor, and will not cause the problem of increased DC resistance of the conductor due to work hardening of the conductor.

[0054] (1.2) The slightly compressed structure makes the conductors tighter and prevents them from becoming loose.

[0055] (1.3) The slightly compressed structure makes the contact area between the inner round single wire layer and the outer profile layer larger, and the structure more stable.

[0056] (1.4) When the measured resistance margin is large, the single wire diameter can be reduced. When the measured resistance margin is small or unqualified, the single wire diameter can be increased. The use of a slightly compressed structure provides adjustable space for increasing or decreasing the single wire diameter without affecting the conductor stranding quality. If a completely non-compressed structure is used, the calculated outer diameter of 12 strands = 3.00*5 = 15.0mm. If the resistance margin is large at this time, the single wire diameter cannot be reduced because reducing the single wire diameter will cause the inner conductor diameter to decrease, resulting in a gap between the outer wire and the inner conductor, making the conductor stranding structure unstable and thus affecting the conductor stranding quality.

[0057] (2) The sub-outer layer 1021 of the composite stranded copper conductor is made of 18 molded wires twisted in the right direction, with a twisting pitch of 360mm-380mm. Due to the twisting and the upper tolerance of the molded wire, the gap between the molded wires will become smaller, which will lead to the squeezing between the sub-outer layer 1021 molded wires and the appearance of a gap between the inner conductor and the sub-outer layer 1021, resulting in poor twisting. Therefore, a gap needs to be left between each molded wire. Since the twisting coefficient is 1.01, the positive tolerance of the molded wire is controlled to be 1%d, so the comprehensive coefficient needs to be ≥1.01*1.01=1.02. Considering that the molded wire may have negative tolerance in actual production, the sub-outer layer 1021 needs to be slightly pressed when twisting to ensure the tightness of the twisted layer. After repeated tests, the dimensions of the molded wire are as follows: the fan length is 3.15mm, the height is 2.50mm, the central angle is 20°, and the minimum cross-section is 6.92mm 2 Assuming no compression, the outer diameter of the 18 strands is calculated as 13.7 mm + 2.50 mm * 2 = 18.7 mm. The stranding die used in this case is 18.4 mm. The sub-outer layer of 1021 copper conductor is lightly compressed, allowing for tighter stranding and a more stable structure. The sector length of each strand is 3.15 mm. The circumference of the 18 strands along their 18.7 mm outer diameter is 18 x 3.15 = 56.7 mm. Before light compression, the outer circumference of the conductors is 18.7 x 3.14 = 58.718 mm. The average gap ratio between each strand is 58.718 / 56.7 mm = 1.036, which is greater than 1.02. This fully meets actual production requirements. The remaining gaps are tightened with light compression.

[0058] (3) The outermost layer 1022 of the composite stranded copper conductor is formed by twisting 24 shaped wires in the left direction, with a twisting pitch of 320mm-340mm. Since the sub-outer layer 1021 is twisted with shaped single wires, the outer diameter is stable and the surface is flat. The shaped single wires of the outermost layer 1022 are twisted on the sub-outer layer 1021 and are relatively stable. In order to make the shaped wires of the outermost layer 1022 twisted without twisting gaps, thereby solving the problem of embedded conductor shielding, it is necessary to comprehensively consider the influence of the upper tolerance, lower tolerance and twisting coefficient of the shaped single wire on the conductor quality. At this time, the gap ratio between the shaped wires should be slightly less than or equal to the comprehensive gap ratio of the shaped single wire caused by the twisting and the upper and lower tolerances of the shaped single wire, and after slight compression, the twisted layer is made tight and seamless.

[0059] Since the stranding coefficient is 1.023 and the positive tolerance of the single wire is controlled at 1% d, the comprehensive coefficient needs to be = 1.023*1.01=1.033. After repeated tests, the fan length is 3.00mm, the height is 2.55mm, the central angle is 15°, and the minimum cross-section is 6.90mm. 2, the outer diameter of 24 strands is calculated as 18.4+2.55*2=23.5mm if it is not compressed at all. The stranding die selected at this time is 23.0mm. At this time, the outermost layer of 1022 copper conductor is a slightly compressed structure, which makes the conductor twisted more tightly. The fan length along the circumference of each wire is 3.00mm. The circumference of 24 wires along the outer diameter of 23.5mm = 24*3.00=72.0mm. The outer circumference of the conductor = 23.5*3.14=73.79mm, the average gap ratio between each wire = 73.79 / 72.0=1.025. At this time, if the tolerance problem of the single wire is considered, the average gap ratio between each wire = 1.025*1.01=1.035, which is very close to the comprehensive coefficient 1.033. At this time, after slight compression, a tightly twisted layer can be obtained, thereby solving the problem of embedded conductor shielding.

[0060] (4) The cross section of the composite stranded copper conductor 1 is 388.5 mm 2 ~392.7mm 2 The conductor cross-section is reduced by about 1% to 2%, achieving the goal of energy conservation and emission reduction.

[0061] (5) The outer diameter of the conductor of the composite stranded copper conductor 1 is 23.0 mm, which meets the requirements of "Table C.2 Maximum and minimum diameters of compressed stranded circular conductors of copper, aluminum and aluminum alloys" in GB / T3956-2008, and solves the problem that the outer diameter of the composite stranded copper conductor is small and cannot be used with cable accessories or hardware. In addition, the outer diameter of the conductor is smaller than the outer diameter of the conductor proposed in patent "ZL202220425611.0", which realizes that in addition to reducing the cost of the conductor, the materials such as conductor shielding, insulation, insulation shielding, copper tape, filling, armoring, and sheath are also reduced due to the reduction of the conductor diameter.

[0062] (6) The maximum DC resistance of the composite stranded high-quality copper conductor at 20°C is 0.0446Ω / km.

[0063] Example 3

[0064] The copper core composite stranded medium voltage power cable is a medium voltage power cable whose conductor adopts the composite stranded copper conductor 1 as mentioned above and is manufactured according to the relevant standards of medium voltage cables. Figure 6 The figure shows a single-core non-armored medium-voltage power cable, the structure and processing method of which are as follows:

[0065] An inner copper conductor 101 and an outer copper conductor 102 are formed into a composite stranded copper conductor 1 according to the method of Example 1 or Example 2; a semi-conductive conductor shielding layer 2, a cross-linked polyethylene (XLPE) insulation layer 3, and an extruded semi-conductive insulation shielding layer 4 are extruded and formed by a three-layer co-extrusion process, and the inner copper conductor 101, the outer copper conductor 102, the semi-conductive conductor shielding layer 2, the cross-linked polyethylene insulation layer 3, and the extruded semi-conductive insulation shielding layer 4 form an insulated wire core from the inside out; a metal shielding layer 5 is provided outside the extruded semi-conductive insulation shielding layer 4, and the metal shielding layer 5 can be wrapped with a metal tape or a sparsely wound metal wire; the metal shielding layer 5 is wrapped with seven layers of wrapping tape to facilitate the next production process; and an outer sheath 10 is extruded outside the wrapping tape 7.

[0066] The above-mentioned profiled copper core composite stranded medium voltage power cable is an example, not a limitation thereof. All medium voltage power cables using the profiled copper core composite stranded conductor 1 described in this technology are applicable to this technology.

[0067] Example 4

[0068] The copper core composite stranded medium voltage power cable is a medium voltage power cable whose conductor adopts the composite stranded copper conductor 1 as mentioned above and is manufactured according to the relevant standards of medium voltage cables. Figure 7 The figure shows a single-core armored medium-voltage power cable, the structure and processing method of which are as follows:

[0069] An inner copper conductor 101 and an outer copper conductor 102 are formed into a composite stranded copper conductor 1 according to the method of Example 1 or Example 2; a semiconductive conductor shielding layer 2, a cross-linked polyethylene insulation layer 3, and an extruded semiconductive insulation shielding layer 4 are extruded and formed by a three-layer co-extrusion technique, and the inner copper conductor 101, the outer copper conductor 102, the semiconductive conductor shielding layer 2, the cross-linked polyethylene insulation layer 3, and the extruded semiconductive insulation shielding layer 4 form an insulated wire core from the inside out; a metal shielding layer 5 is provided outside the extruded semiconductive insulation shielding layer 4, and the metal shielding layer 5 can be wrapped with a metal tape or a sparsely wound metal wire; the metal shielding layer 5 is wrapped with 7 layers of wrapping tape to facilitate the next production process; an isolation sleeve 8 is extruded outside the wrapping tape 7; an armor layer 9 is provided outside the isolation sleeve 8, and the armor layer 9 can be non-magnetic metal tape interstitial armor or non-magnetic metal wire armor; and an outer sheath 10 is extruded outside the armor layer 9.

[0070] The above-mentioned profiled copper core composite stranded medium voltage power cable is an example, not a limitation thereof. All medium voltage power cables using the profiled copper core composite stranded conductor 1 described in this technology are applicable to this technology.

[0071] Example 5

[0072] The copper core composite stranded medium voltage power cable is a medium voltage power cable whose conductor adopts the composite stranded copper conductor 1 as mentioned above and is manufactured according to the relevant standards of medium voltage cables. Figure 8The following is a 3-core non-armored medium voltage power cable. Its structure and processing method are as follows:

[0073] An inner copper conductor 101 and an outer copper conductor 102 are formed into a composite stranded copper conductor 1 according to the method of Example 1 or Example 2; a semi-conductive conductor shielding layer 2, a cross-linked polyethylene insulation layer 3, and an extruded semi-conductive insulation shielding layer 4 are extruded and formed by a three-layer co-extrusion technology, and the inner copper conductor 101, the outer copper conductor 102, the semi-conductive conductor shielding layer 2, the cross-linked polyethylene insulation layer 3, and the extruded semi-conductive insulation shielding layer 4 form an insulated wire core from the inside out; a metal shielding layer 5 is provided outside the extruded semi-conductive insulation shielding layer 4, and the metal shielding layer 5 can be wrapped with a metal tape or a sparsely wound metal wire, and the insulated wire core and the metal shielding layer 5 form a metal shielding wire core; three identical metal shielding wire cores are twisted in the right direction into a cable, and the gaps between the twisted metal shielding wire cores are filled with a filling material 6 to make them round, and the twisted metal shielding wire cores are tightened by a wrapping tape 7; an outer sheath 10 is extruded outside the wrapping tape 7;

[0074] The above-mentioned profiled copper core composite stranded medium voltage power cable is an example, not a limitation thereof. All medium voltage power cables using the profiled copper core composite stranded conductor 1 described in this technology are applicable to this technology.

[0075] Example 6

[0076] The copper core composite stranded medium voltage power cable is a medium voltage power cable whose conductor adopts the composite stranded copper conductor 1 as mentioned above and is manufactured according to the relevant standards of medium voltage cables. Figure 9 The following is a 3-core armored medium voltage power cable. Its structure and processing method are as follows:

[0077] The inner copper conductor 101 and the outer copper conductor 102 are formed into a composite stranded copper conductor 1 according to the method of Example 1 or Example 2; the semi-conductive conductor shielding layer 2, the cross-linked polyethylene insulation layer 3, and the extruded semi-conductive insulation shielding layer 4 are extruded by a three-layer co-extrusion technology, and the inner copper conductor 101, the outer copper conductor 102, the semi-conductive conductor shielding layer 2, the cross-linked polyethylene insulation layer 3, and the extruded semi-conductive insulation shielding layer 4 form an insulated wire core from the inside out; the extruded semi-conductive insulation shielding layer 4 is provided with a metal shield Layer 5, the metal shielding layer 5 can be wrapped with metal tape or metal wire, and the metal shielding core is composed of the insulated core and the metal shielding layer 5; three identical metal shielding cores are twisted into a cable in the right direction, and the gaps between the twisted metal shielding cores are filled with filling material 6 to make them round, and the twisted metal shielding cores are tightened by wrapping tape 7; an isolation sleeve 8 is extruded outside the wrapping tape 7; outside the isolation sleeve 8 is an armor layer 9, which can be metal tape gap armor or metal wire armor; outside the armor layer 9 is an outer sheath 10;

[0078] The above-mentioned profiled copper core composite stranded medium voltage power cable is an example, not a limitation thereof. All medium voltage power cables using the profiled copper core composite stranded conductor 1 described in this technology are applicable to this technology.

Claims

1. A composite stranded copper conductor, characterized in that: The invention comprises an inner copper conductor (101) and an outer copper conductor (102), wherein the inner copper conductor (101) is formed by compacting and twisting 1 to 4 layers of circular annealed copper single wires of equal outer diameter; and the outer copper conductor (102) is formed by compacting and twisting 1 to 4 layers of special-shaped annealed copper single wires, wherein the cross section of the special-shaped annealed copper single wire is a fan ring.

2. The composite stranded copper conductor according to claim 1, characterized in that: The composite stranded copper conductor is 400 mm 2 A composite stranded copper conductor (1) comprises an inner copper conductor (101) and an outer copper conductor (102), wherein the inner copper conductor (101) is formed by compactly twisting three layers of circular annealed copper wires of equal outer diameter; and the outer copper conductor (102) is formed by compactly twisting two layers of special-shaped annealed copper wires, wherein the cross-section of the special-shaped annealed copper wires is a fan-shaped ring. The inner copper conductor (101) is formed by twisting and pressing 19 round single wires with a diameter of 2.93 mm in three layers according to the regular 1+6+12 method. Specifically, the first layer (1011) has one round single wire which is laid straight; the second layer (1012) has six round single wires which are twisted in the right direction with a twist pitch of 240 mm to 260 mm, and then the second layer (1012) is twisted using a twisting die with an inner diameter of 8.2 mm; the third layer (1013) has twelve round single wires which are twisted in the left direction with a twist pitch of 370 mm to 390 mm, and are again twisted using a twisting die with an inner diameter of 13.4 mm. The outer copper conductor (102) is formed by twisting 42 single wires in two layers in 18+24 degrees and pressing them tightly; 18 single wires are twisted in the right direction to form a secondary outer layer (1021) of the composite stranded copper conductor; the single wire fan length of the secondary outer layer (1021) is 3.05 mm, the height is 2.46 mm, the center angle is 20 degrees, and the minimum cross-section is 6.55 mm 2 The stranding pitch is 350mm-370mm, and the stranding mold with an inner diameter of 17.9mm is used for compacting; 24 single wires are twisted in the left direction to form the outermost layer (1022) of the composite stranded copper conductor, and the fan length of the single wire of the outermost layer (1022) is 2.92mm, the height is 2.5mm, the central angle is 15°, and the minimum cross-section is 6.53mm 2 The stranding pitch is 320mm-340mm, and it is compacted using a compact stranding die with an inner diameter of 22.5mm.

3. The composite stranded copper conductor according to claim 1, characterized in that: The composite stranded copper conductor is 400 mm 2 A composite stranded copper conductor (1) comprises an inner copper conductor (101) and an outer copper conductor (102), wherein the inner copper conductor (101) is formed by compactly twisting three layers of circular annealed copper wires of equal outer diameter; and the outer copper conductor (102) is formed by compactly twisting two layers of special-shaped annealed copper wires, wherein the cross-section of the special-shaped annealed copper wires is a fan-shaped ring. The inner copper conductor (101) is formed by twisting 19 round single wires with a diameter of 3.00 mm in three layers in a regular 1+6+12 pattern. Specifically, the first layer (1011) comprises one round single wire which is laid straight; the second layer (1012) comprises six round single wires which are twisted in the right direction with a twist pitch of 240 mm to 260 mm, and then the second layer (1012) is twisted using a twisting die with an inner diameter of 8.4 mm; the third layer (1013) comprises twelve round single wires which are twisted in the left direction with a twist pitch of 370 mm to 390 mm, and then the twisting die is twisted again using a twisting die with an inner diameter of 13.7 mm. The outer copper conductor (102) is formed by twisting 42 single wires in two layers in 18+24 degrees and pressing them tightly; 18 single wires are twisted in the right direction to form a secondary outer layer (1021) of the composite stranded copper conductor; the dimensions of the single wires in the secondary outer layer (1021) are: a fan length of 3.15 mm, a height of 2.50 mm, a central angle of 20 degrees, and a minimum cross-section of 6.92 mm 2 The stranding pitch is 360mm-380mm, and the stranding mold with an inner diameter of 18.4mm is used for compaction; 24 single wires are twisted in the left direction to form the outermost layer (1022) of the composite stranded copper conductor, and the single wire fan length of the outermost layer (1022) is 3.00mm, the height is 2.55mm, the central angle is 15°, and the minimum cross-section is 6.90mm 2 The stranding pitch is 320mm-340mm, and it is compacted using a compact stranding die with an inner diameter of 23.0mm.

4. A medium voltage power cable, characterized in that: From the inside to the outside, it comprises the composite stranded copper conductor (1) according to any one of claims 1 to 3, a semi-conductive conductor shielding layer (2), a cross-linked polyethylene insulation layer (3), an extruded semi-conductive insulation shielding layer (4), a metal shielding layer (5), a wrapping tape (7), and an outer sheath (10).

5. The medium voltage power cable according to claim 4, characterized in that The metal shielding layer (5) is obtained by wrapping a metal tape or a metal wire.

6. The medium voltage power cable according to claim 4, characterized in that When the shaped copper core composite twisted medium voltage power cable contains three shaped composite twisted copper conductors (1), each shaped composite twisted copper conductor (1) and a semi-conductive conductor shielding layer (2), a cross-linked polyethylene insulation layer (3), and an extruded semi-conductive insulation shielding layer (4) form an insulation core from the inside out; a metal shielding layer (5) is wrapped around the insulation core to form a metal shielding core; three identical metal shielding cores are twisted in the right direction to form a cable, gaps in the twisted metal shielding cores are filled with a filling material (6) to make them round, and the twisted metal shielding cores are tied tightly with a wrapping tape (7); and an outer sheath (10) is extruded outside the wrapping tape (7).

7. The medium voltage power cable according to claim 4 or 6, characterized in that: An isolation sleeve (8) and an armor layer (9) are sequentially arranged between the wrapping tape (7) and the outer sheath (10) from the inside to the outside.

8. The medium voltage power cable according to claim 7, characterized in that: The armor layer (9) is metal tape gap armor or metal wire armor.

Images