15 kv kink and crush resistant adjustable power cable

Abstract

The application discloses a 15kV bending and pressure resistant adjustable power cable and belongs to the technical field of power cables. The power cable comprises a conductor located at the innermost layer, an insulating layer located outside the conductor, a fire-resistant layer located outside the insulating layer, a shielding layer located outside the fire-resistant layer, a filling layer located outside the shielding layer, and a sheath layer located outside the filling layer. A spiral arrangement groove extending from the head end to the tail end is formed on the outer surface of the filling layer, and a spiral bending and pressure resistant structure and a steel wire rope wrapped around the spiral bending and pressure resistant structure are arranged in the spiral arrangement groove. A tension adjusting mechanism is arranged on the outer surface of the sheath layer and is connected to the two ends of the steel wire rope and leads the steel wire rope out of the sheath layer. The tension adjusting mechanism changes the tension degree of the steel wire rope to adjust the bending and pressure resistance of the whole power cable. The power cable can flexibly adjust the mechanical strength and bending stiffness of the whole cable in different periods, is convenient to transport and wind, and can provide high bending and pressure resistance protection after laying.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, specifically a 15kV adjustable power cable with bending and pressure resistance. Background Technology

[0002] 15kV power cables refer to power cables with a rated voltage of 15 kV (AC), belonging to the category of medium-voltage cables, and are mainly used for transmitting and distributing electrical energy in 15kV power distribution networks. The cable's bending and compressive strength are key indicators to ensure its long-term stable operation.

[0003] In existing technologies, to improve the bending and compressive strength of 15kV power cables, the following technical means are commonly used: increasing the thickness of the armor layer, using high-hardness sheath materials, and incorporating a built-in fixed support frame. Although this structure provides a certain degree of support, its mechanical properties are fixed and cannot be adjusted, leading to the following common problems in practical applications: The contradiction between bending and compressive strength and transportation flexibility: 15kV bending and compressive strength adjustable power cables usually need to be wound on cable reels for long-distance transportation after leaving the factory. If the bending and compressive strength of the cable itself is designed to be too strong (i.e., too stiff), the cable is extremely difficult to bend and cannot be wound on a standard cable reel, or irreversible bending damage to the internal conductor and insulation layer may occur during winding. Conversely, if the stiffness is reduced to facilitate transportation, its bending and compressive strength will be insufficient, which will seriously shorten its service life. Lack of dynamic adjustment mechanism: Once the existing cable structure is formed, its mechanical properties are fixed and cannot be dynamically adjusted according to the different stages of the cable (transportation state and working state). Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a 15kV adjustable power cable with bending and compressive strength, which can flexibly adjust the overall mechanical strength and bending stiffness of the cable at different times (such as transportation and laying periods), which is convenient for transportation and winding, and can provide high bending and compressive strength protection after laying, so as to solve the problems of non-adjustable bending and compressive strength and contradictory mechanical performance during transportation and use in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A 15kV adjustable power cable with bending and pressure resistance includes an innermost conductor, an insulation layer on the outside of the conductor, a fire-resistant layer on the outside of the insulation layer, a shielding layer on the outside of the fire-resistant layer, a filling layer on the outside of the shielding layer, and a sheath layer on the outside of the filling layer. Its core improvement lies in the following: a spiral groove extending from the first end to the last end is formed on the outer surface of the filling layer, and a spiral bending and pressure-resistant structure and a steel wire rope wrapped around the spiral bending and pressure-resistant structure are arranged within the spiral groove; a tension adjustment mechanism is provided on the outer surface of the sheath layer, connecting the two ends of the steel wire rope and leading the steel wire rope out of the sheath layer. The tension adjustment mechanism changes the tension of the steel wire rope to adjust the bending and pressure resistance of the entire power cable.

[0006] By adopting the above scheme, during transportation, the tension of the steel wire rope is released through the tension adjustment mechanism, and the spiral anti-bending and anti-compression structure is in a relatively relaxed state. At this time, the cable has good overall flexibility and can be easily wound on the cable reel. After being transported to the site for laying, the steel wire rope is tightened through the tension mechanism, which forces the spiral segment to be taut, and the cable instantly becomes a high-rigidity state, improving its anti-compression and anti-bending capabilities.

[0007] As a preferred embodiment of a 15kV adjustable power cable with bending and pressure resistance, the spiral bending and pressure resistance structure is composed of multiple spiral bending and pressure resistance segments spliced ​​end to end, with splicing gaps between each spiral bending and pressure resistance segment; it adopts a split segment splicing rather than an integrated structure, which facilitates manufacturing and installation; when a local segment is damaged, it can be replaced individually, reducing maintenance costs, while the gaps between segments allow the cable to have better bending flexibility in a relaxed state.

[0008] As a preferred embodiment of a 15kV adjustable power cable with bending and pressure resistance, the spiral angle of the spiral bending and pressure resistance segment is 60°-180°. This spiral angle range ensures that the segment has a certain support length in the axial direction, which can provide sufficient radial pressure resistance area, and will not cause excessive axial stiffness due to too small a spiral angle (too steep), thus achieving a balance between support force and flexibility.

[0009] As a preferred embodiment of a 15kV adjustable power cable with bending and pressure resistance, the spiral bending and pressure resistance segment is made of high-rigidity metal material, such as steel. The high elastic modulus and yield strength of the metal provide core rigid support for the cable. When the wire rope is tensioned, the metal segments squeeze or press against each other to form a mechanical structure similar to a "rigid tube", which greatly improves the overall rigidity.

[0010] As a preferred embodiment of a 15kV adjustable power cable with bending and pressure resistance, a spiral limiting groove is provided on the outer surface of the spiral bending and pressure resistance section. The steel wire rope is located in the spiral limiting groove and is used to connect all the spiral bending and pressure resistance sections end to end. The spiral limiting groove prevents the steel wire rope from radially slipping or shifting during tensioning or slack-off, ensuring the effective transmission of tension force. The series structure allows the stiffness of the entire cable to be controlled by a single steel wire rope, greatly simplifying the installation of the spiral bending and pressure resistance structure.

[0011] As a preferred embodiment of a 15kV adjustable power cable with bending and pressure resistance, the diameter of the wire rope is equal to the width of the spiral limiting groove. Through the design of interference fit or tight fit, the swaying space of the wire rope in the groove is eliminated, so that the wire rope can directly convert the tension into the radial constraint force on the segment, improve the adjustment response speed and accuracy, and avoid local bending caused by gaps.

[0012] As a preferred embodiment of a 15kV bending and pressure resistant adjustable power cable, the tension adjustment mechanism includes a fixed tensioning nozzle fixedly connected to the sheath layer, an adjustable tensioning nozzle threadedly fitted inside the fixed tensioning nozzle, and a tensioning ball fixedly connected to the end of the wire rope at the outer end of the adjustable tensioning nozzle. The tension of the wire rope can be adjusted by changing the relative position of the fixed tensioning nozzle and the adjustable tensioning nozzle. The threaded adjustment mechanism can convert rotational motion into precise axial displacement, realizing fine adjustment of the tension. Furthermore, the self-locking characteristic of the thread ensures the stability of the tension during cable operation and prevents it from loosening due to vibration.

[0013] As a preferred embodiment of a 15kV bending and pressure resistant adjustable power cable, the distance between the two sets of tension adjustment mechanisms extending from both ends of the wire rope to outside the sheath layer does not exceed 3M. By limiting the distance between the adjustment mechanisms, uneven tension of the wire rope in the middle section caused by excessive span is avoided. The shorter distance allows the tension force to be distributed more evenly throughout the cable section, ensuring the consistency of the adjustment effect.

[0014] As a preferred embodiment of a 15kV bend- and pressure-resistant adjustable power cable, two symmetrically distributed rotary handles are connected to the outer end of the adjustable tensioning nozzle, providing a convenient manual operation interface. Construction personnel can perform tensioning operations without special tools, improving the efficiency and convenience of on-site construction.

[0015] As a preferred embodiment of a 15kV bending and pressure resistant adjustable power cable, the surface of the tensioning ball is polished. Polishing reduces surface roughness and decreases the coefficient of friction between the adjustable tensioning nozzle and the tensioning ball, making the adjustment process smoother and less labor-intensive. It also reduces wear on the contact surface and extends the service life of the adjustment mechanism.

[0016] The beneficial effects of this invention are: 1. Resolves the contradiction between transportation and use: During transportation, the tension of the steel wire rope is released through the tension adjustment mechanism, and the spiral anti-bending and anti-compression structure is in a relaxed state, with good overall cable flexibility, which can be easily wound on the cable reel; after being transported to the site for laying, the steel wire rope is tightened through the tension mechanism, forcing the spiral segment to tighten, and the cable instantly becomes a high-rigidity state, improving its compressive and bending resistance. 2. Convenient and precise adjustment: The tensioning nozzle structure with threaded engagement provides high adjustment precision and stepless adjustment to meet the different requirements of cable stiffness under different geological conditions. 3. Strong structural stability: The tight fit between the spiral limiting groove and the steel wire rope, as well as the high rigidity of the metal segments, ensure that the cable can resist external pressure like a rigid pipe under tension, protecting the internal conductor from damage. 4. Easy maintenance: The modular design of the segmented structure and the exposed adjustment mechanism make local maintenance and tension re-tightening simple. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A three-dimensional structural diagram of a 15kV adjustable power cable with bending and pressure resistance; Figure 2 for Figure 1 Partial three-dimensional structural diagram; Figure 3 for Figure 2 Front view structure diagram; Figure 4 for Figure 2 Internal three-dimensional structure diagram; Figure 5 To hide Figure 2 Three-dimensional structural diagram of the layer behind the middle sheath; Figure 6 This is a 3D structural diagram of the filling layer; Figure 7 A three-dimensional structural diagram of a spiral bending and compressive duct. Figure 8 A three-dimensional structural diagram of the spiral bending and compressive resistance structure connected by steel wire ropes; Figure 9 for Figure 4 A magnified view of a portion of point A in the middle.

[0019] The markings in the diagram are: 1-Conductor; 2-Insulation layer; 3-Fire-resistant layer; 4-Shielding layer; 5-Filling layer; 6-Sheath layer; 7-Spiral arrangement groove; 8-Spiral bending and compressive strength structure; 81-Spiral bending and compressive strength segment; 82-Spiral limiting groove; 9-Wire rope; 10-Tension adjustment mechanism; 101-Fixed tensioning nozzle; 102-Adjustable tensioning nozzle; 103-Tensioning ball; 104-Rotating handle. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figures 1 to 6 As shown, a 15kV adjustable power cable with bending and pressure resistance is provided, suitable for urban power distribution networks, internal power supply of industrial enterprises, and collection lines of new energy power plants, etc., specifically including: Conductor 1: Located in the innermost layer, it is a fan-shaped segmented conductor 1, made of copper or aluminum. The fan-shaped segmented structure is formed by a molding process, and gaps are retained between adjacent fan-shaped blocks to reduce the skin effect. Insulation layer 2: Located on the outside of conductor 1, made of cross-linked polyethylene (XLPE) or polyvinyl chloride (PVC), used to isolate conductor 1 from the external structure and to carry the rated voltage; Fire-resistant layer 3: Located outside the insulation layer 2, the material is a mica tape (such as phlogopite or synthetic mica) wrapping layer, with a temperature resistance of ≥1000℃, used to maintain insulation performance in case of fire; Shielding layer 4: Located on the outside of the fire-resistant layer 3, the material is copper wire braided shielding layer 4 or copper strip wrapped shielding layer 4, used to suppress electromagnetic interference and provide grounding protection; Filler layer 5: Located outside the shielding layer 4, the material is flame-retardant polypropylene (PP) or silicone rubber foam, used to maintain the round structure of the cable and assist in flame retardancy; Sheath layer 6: Located outside the filler layer 5, the material is low smoke halogen-free flame retardant polyolefin (LSZH) or thermoplastic polyurethane elastomer (TPU), providing mechanical protection and environmental resistance. The cable features a spiral groove 7 extending from one end to the other on the outer surface of the filler layer 5. A spiral bending and compressive strength structure 8 and a steel wire rope 9 wrapped around the spiral bending and compressive strength structure 8 are arranged within the spiral groove 7. A tension adjustment mechanism 10 connects the two ends of the steel wire rope 9 and leads it out of the sheath layer 6. The tension adjustment mechanism 10 changes the tension of the steel wire rope 9 to adjust the bending and compressive strength of the entire power cable. During transport, the tension of the steel wire rope 9 is released by the tension adjustment mechanism 10, leaving the spiral bending and compressive strength structure 8 in a relatively relaxed state. At this time, the cable has good overall flexibility and can be easily wound onto a cable reel. After being transported to the site for installation, the tension mechanism tightens the steel wire rope 9, forcing the spiral segment to taut, instantly transforming the cable into a high-rigidity state and improving its compressive and bending resistance.

[0022] like Figures 7 to 8 As shown, the spiral bending and pressure-resistant structure 8 is composed of multiple spiral bending and pressure-resistant segments 81 spliced ​​together end to end, and there are splicing gaps between each spiral bending and pressure-resistant segment 81; it adopts a split segment splicing rather than an integrated structure, which facilitates production and installation; when a local segment is damaged, it can be replaced individually, reducing maintenance costs, while the gaps between segments allow the cable to have better bending flexibility in a relaxed state.

[0023] like Figure 7 As shown, the helix angle of the spiral bending and compressive segment 81 is 180°. The helix angle can be within the range of 60°-180°. This range of helix angles ensures that the segment has a certain support length in the axial direction, which can provide sufficient radial compressive area, and will not cause excessive axial stiffness due to the helix angle being too small (too steep), thus achieving a balance between support force and flexibility.

[0024] like Figure 7 As shown, the spiral bending and compressive resistance segment 81 is made of high-rigidity metal material, such as steel. It utilizes the high elastic modulus and yield strength of the metal to provide core rigid support for the cable. When the wire rope 9 is tensioned, the metal segments squeeze or press against each other to form a mechanical structure similar to a "rigid tube", which greatly improves the overall rigidity.

[0025] like Figures 7 to 8 As shown, a spiral limiting groove 82 is provided on the outer surface of the spiral bending and pressure-resistant segment 81. The steel wire rope 9 is located in the spiral limiting groove 82 and is used to connect all the spiral bending and pressure-resistant segments 81 end to end. The spiral limiting groove 82 prevents the steel wire rope 9 from radially slipping or shifting during tensioning or slack-off, ensuring the effective transmission of tension force. The series structure allows a single steel wire rope 9 to control the stiffness of the entire cable, greatly simplifying the installation of the spiral bending and pressure-resistant structure 8.

[0026] like Figure 7 As shown, the diameter of the wire rope 9 is equal to the width of the spiral limiting groove 82. Through the design of interference fit or tight fit, the swaying space of the wire rope 9 in the groove is eliminated, so that the wire rope 9 can directly convert the tension into the radial constraint force on the segment, improve the adjustment response speed and accuracy, and avoid local bending caused by gap.

[0027] like Figure 4 , Figure 9 As shown, the tension adjustment mechanism 10 includes a fixed tensioning nozzle 101 fixedly connected to the sheath layer 6, and an adjustable tensioning nozzle 102 threadedly fitted inside the fixed tensioning nozzle 101. A tensioning ball 103 fixedly connected to the end of the wire rope 9 is abutted at the outer end of the adjustable tensioning nozzle 102. The tension of the wire rope 9 can be adjusted by changing the relative position of the fixed tensioning nozzle 101 and the adjustable tensioning nozzle 102. The threaded adjustment mechanism can convert rotational motion into precise axial displacement, realize fine adjustment of tension, and the self-locking characteristic of the thread ensures the stability of the tension during cable operation and will not loosen due to vibration.

[0028] like Figure 1 As shown, the distance between the two sets of tension adjustment mechanisms 10 leading the two ends of the wire rope 9 out of the sheath layer 6 does not exceed 3M. By limiting the distance between the adjustment mechanisms, uneven tension in the middle section of the wire rope 9 caused by excessive span is avoided. The shorter distance allows the tension force to be distributed more evenly throughout the cable section, ensuring the consistency of the adjustment effect.

[0029] like Figure 9 As shown, two symmetrically distributed rotary handles 104 are connected to the outer end of the adjustable tensioning nozzle 102, providing a convenient manual operation interface. Construction personnel can perform tensioning operations without special tools, which improves the efficiency and convenience of on-site construction.

[0030] like Figure 9 As shown, the surface of the tensioning ball 103 is polished. Polishing reduces the surface roughness and decreases the coefficient of friction between the adjustable tensioning nozzle 102 and the tensioning ball 103, making the adjustment process smoother and less strenuous. It also reduces wear on the contact surface and extends the service life of the adjustment mechanism.

[0031] like Figures 1 to 9 As shown, the working principle of this 15kV bend- and pressure-resistant adjustable power cable is as follows: Relaxation adjustment (transportation / rewinding): Adjust the tension adjustment mechanism 10 to the relaxed state. At this time, the wire rope 9 does not apply axial tension to the spiral bending and compressive structure 8. The spiral bending and compressive segment 81 is in a free or slightly contacted state in the spiral arrangement groove 7. Relative movement between segments is allowed. At this time, the cable as a whole mainly relies on the flexibility of the material itself and can be bent and wound at large angles without damaging the internal structure. Tensioning Adjustment (Laying): After the cable is laid in place, the operator uses tools or rotates handle 104 to turn the adjustable tensioning nozzle 102. Since the fixed tensioning nozzle 101 is fixed to the sheath layer 6, the adjustable tensioning nozzle 102 is pushed axially into the cable under the action of the thread, pushing the tensioning ball 103 to further tighten the wire rope 9. After the wire rope 9 is tightened, the axial tension it generates is transmitted to each spiral bending and compressive strength segment 81 through the spiral limiting groove 82, making them fit tightly against each other. Since the spiral bending and compressive strength segments 81 are made of high-rigidity metal material, they form a continuous, rigid support layer similar to a "spring steel ring". The cable as a whole exhibits extremely high bending stiffness and compressive strength, thereby protecting the internal conductor 1 and insulation layer 2 from external damage.

[0032] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A 15kV adjustable power cable with bending and pressure resistance, comprising an innermost conductor, an insulation layer on the outside of the conductor, a fire-resistant layer on the outside of the insulation layer, a shielding layer on the outside of the fire-resistant layer, a filling layer on the outside of the shielding layer, and a sheathing layer on the outside of the filling layer; characterized in that: A spiral groove extending from its head to its tail is formed on the outer surface of the filler layer, and a spiral bending and compressive strength structure and a steel wire rope wrapped around the spiral bending and compressive strength structure are arranged in the spiral groove. A tension adjustment mechanism is provided on the outer surface of the sheath layer to connect the two ends of the steel wire rope and lead the steel wire rope out of the sheath layer. The tension adjustment mechanism changes the tension of the steel wire rope to adjust the bending and compressive strength of the entire power cable.

2. The 15kV bend-resistant and compression-resistant adjustable power cable according to claim 1, characterized in that, The spiral bending and compressive strength structure is composed of multiple spiral bending and compressive strength segments spliced ​​together end to end, and there are splicing gaps between each spiral bending and compressive strength segment.

3. The 15kV bend-resistant and compression-resistant adjustable power cable according to claim 2, characterized in that, The helix angle of the spiral bending and compressive strength segment is 60°-180°.

4. The 15kV bend-resistant and compression-resistant adjustable power cable according to claim 2, characterized in that, The spiral bending and compressive resistant segments are made of high-rigidity metal materials.

5. The 15kV bend-resistant and compression-resistant adjustable power cable according to claim 2, characterized in that, A spiral limiting groove is provided on the outer surface of the spiral bending and compressive resistance segment, in which the steel wire rope is located in the spiral limiting groove and the ends of all the spiral bending and compressive resistance segments are connected in series.

6. The 15kV bend-resistant and compression-resistant adjustable power cable according to claim 5, characterized in that, The diameter of the wire rope is equal to the width of the spiral limiting groove.

7. The 15kV bend-resistant and compression-resistant adjustable power cable according to claim 1, characterized in that, The tension adjustment mechanism includes a fixed tensioning nozzle fixedly connected to the sheath layer, an adjustable tensioning nozzle threadedly fitted inside the fixed tensioning nozzle, and a tensioning ball fixedly connected to the end of the wire rope abutting at the outer end of the adjustable tensioning nozzle. The tension of the wire rope can be adjusted by changing the relative position of the fixed tensioning nozzle and the adjustable tensioning nozzle.

8. The 15kV bend-resistant and compression-resistant adjustable power cable according to claim 7, characterized in that, The distance between the two sets of tensioning adjustment mechanisms that extend the two ends of the wire rope beyond the sheath layer shall not exceed 3 meters.

9. The 15kV bend-resistant and compression-resistant adjustable power cable according to claim 7, characterized in that, Two symmetrically distributed rotating handles are connected to the outer end of the adjustable tensioning nozzle.

10. The 15kV bend-resistant and compression-resistant adjustable power cable according to claim 7, characterized in that, The surface of the tensioning top ball is polished.

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