Insulated power cable and braiding process thereof

Abstract

This invention relates to the field of power cable technology and provides an insulated power cable including a conductor layer; the outer side of the conductor layer is provided with a buffer shielding layer, an insulation layer, an insulation shielding layer, a braided reinforcement layer, a buffer repair layer, and a sheath layer in succession; the conductor layer includes a reinforcing core and an outer conductor one and an outermost conductor two, the cross-section of the conductor two being trapezoidal; the braided reinforcement layer includes an inner braided composite layer and an outer braided layer, with anchoring units fixed at the intersection of the inner braided composite layer and the outer braided layer; the buffer repair layer includes a metal corrugated skeleton and an inner flexible coating. The trapezoidal structure of the conductor two increases the contact surface, forming a heat dissipation channel in conjunction with the anchoring units. The composite braiding of the inner and outer braided layers and the anchoring at the intersections quickly disperse external impact forces. Simultaneously, the buffer repair layer enhances resistance to external forces, and repair microcapsules automatically fill defect gaps.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, and more specifically, to an insulated power cable and its braiding process. Background Technology

[0002] Insulated power cables are cables composed of conductors, insulation layers, and protective layers. They are mainly used to transmit and distribute electrical energy. Their insulation layers can effectively isolate the conductors, prevent leakage and short circuits, and ensure safe and stable power transmission. Common insulation materials include cross-linked polyethylene and other materials, which have heat resistance and voltage resistance characteristics. They are widely used in urban power grids, industrial and mining enterprises, and power transmission inside buildings, with voltage levels covering low and medium voltage to ultra-high voltage.

[0003] Currently, the shielding braid of traditional cables is directly braided layer by layer with copper wire or other wires. It has low mechanical strength and is easily affected by working conditions such as cable bending, resulting in gaps. It cannot have both good shielding and mechanical protection performance.

[0004] To address the aforementioned problems, this application proposes an insulated power cable and its braiding process. Summary of the Invention

[0005] The purpose of this invention is to provide an insulated power cable and its braiding process, which solves the problem that the existing cable braiding structure is simple and cannot simultaneously provide shielding and mechanical protection.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0007] An insulated power cable, comprising a conductor layer;

[0008] The outer side of the conductor layer is provided with a buffer shielding layer, an insulation layer, an insulation shielding layer, a braided reinforcement layer, a buffer repair layer, and a sheath layer, layer by layer.

[0009] The conductor layer includes a reinforcing core and an outer conductor one, as well as an outermost conductor two, the cross-section of which is trapezoidal;

[0010] The braided reinforcement layer includes an inner braided composite layer and an outer braided layer, and an anchoring unit is fixed at the intersection of the inner braided composite layer and the outer braided layer.

[0011] The buffer repair layer includes a metal corrugated skeleton and a flexible coating on its inner side.

[0012] A braiding process for insulated power cables, characterized by comprising a braiding system, wherein the specific braiding steps of the braiding system for the braided reinforcing layer are as follows:

[0013] S1. On the cable braiding production line, the first braiding unit and the second braiding unit are arranged in series to braid the inner braided composite layer and the outer braided layer, respectively.

[0014] S2. On the cable braiding production line, a vision control unit is set up to identify the braiding intersection of the inner braided composite layer and the outer braided layer.

[0015] S3. On the cable braiding production line, a wire feeding unit, a heat melting unit, and a cooling unit are arranged.

[0016] The vision control unit controls the wire feeding unit to insert the hot melt wire into the intersection area, and then controls the hot melt unit to move towards the hot melt wire. Subsequently, the cooling unit implements low-temperature cooling to solidify the anchoring structure.

[0017] S4. Traction units are also arranged on the cable braiding production line, distributed at the inlet and outlet of the braiding system.

[0018] The beneficial effects of this invention are:

[0019] 1. By weaving an inner braided composite layer and an outer braided composite layer structure on the inner side of the sheath layer, and anchoring at the braiding intersections by anchoring units, bidirectional transmission in both circumferential and axial directions can be formed after the cable is subjected to external impact, thereby avoiding stress concentration in local areas and causing damage to the cable structure. The metal material of the inner braided composite layer can also accelerate the rapid dissipation of heat inside the cable.

[0020] 2. By twisting the reinforcing core with a circular cross-section in the inner ring and the outermost trapezoidal cross-section conductor two, the contact surface between the conductor layer and the buffer shielding layer can be increased. This can reduce the gap to equalize the electric field and promote the outward dissipation of heat through the increased contact surface, forming a rapid radial heat dissipation path in conjunction with the inner braided composite layer.

[0021] 3. By setting a composite structure buffer and repair layer between the sheath layer and the braided reinforcement layer, the undulating structure composed of convex and concave corrugations buffers the impact on the outside of the cable, reducing the impact on the braided reinforcement layer. At the same time, the repair capsules in the flexible coating promptly fill the damaged gaps, thus achieving the dual effect of protection and self-repair, which helps to protect the integrity of the cable structure in the long term. Attached Figure Description

[0022] 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, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1This is a schematic diagram of the overall appearance structure of the cable of the present invention;

[0024] Figure 2 This is a schematic diagram of the radial cross-sectional structure of the cable according to the present invention;

[0025] Figure 3 This is a schematic diagram of the axial planar structure of the cable of the present invention;

[0026] Figure 4 This is a schematic diagram of the radial cross-sectional structure of the conductor layer and buffer shielding layer combination of the present invention;

[0027] Figure 5 This is a schematic diagram of the conductor's two radial cross-section structure according to the present invention;

[0028] Figure 6 This is a schematic diagram of the combined structure of the buffer repair layer and the sheath layer of the present invention;

[0029] Figure 7 This is a schematic diagram of the three-dimensional structure of the braided reinforcement layer of the present invention;

[0030] Figure 8 This is a schematic diagram of the combined structure of the anchoring unit, the inner braided composite layer, and the outer braided layer of the present invention;

[0031] Figure 9 This is a schematic diagram of the weaving process of the present invention;

[0032] The attached diagram lists the components represented by each number as follows:

[0033] In the diagram: 1. Conductor layer; 2. Buffer shielding layer; 3. Insulating layer; 4. Insulating shielding layer; 5. Braided reinforcement layer; 6. Buffer repair layer; 7. Sheath layer;

[0034] 11. Reinforcing core; 12. Conductor 1; 13. Conductor 2; 131. Outer arc surface; 132. Inner arc surface; 133. Side arc surface;

[0035] 51. Anchoring unit; 511. Hot melt wire; 52. Inner braided composite layer; 521. Flat filament; 522. Round filament; 53. Outer braided layer; 531. Round filament braid;

[0036] 61. Outwardly convex corrugated joint; 62. Inwardly concave corrugated joint; 63. Flexible coating; 631. Filler portion; 6301. Repair microcapsule;

[0037] 71. Inner convex part. Detailed Implementation

[0038] 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.

[0039] An insulated power cable and its braiding process are designed to improve the stability and integrity of the cable structure. The trapezoidal structure of conductor 13 increases the contact surface with the outer structure, and together with the anchoring unit 51, it forms a heat dissipation channel. In addition, the inner and outer braided composite layer 52 and the outer braided layer 53 are combined with the cross-point anchoring structure to quickly disperse external impact forces along the circumferential and axial directions to prevent stress concentration from causing direct damage. At the same time, the buffer repair layer 6 further enhances the resistance to external forces, and the repair microcapsules 6301 in the flexible coating 63 can automatically fill defect gaps, which helps to maintain the structural stability and integrity of the cable during long-term use.

[0040] In some embodiments, the specific structure of the insulated power cable is as follows: Figure 1-3 As shown, it includes a conductor layer 1 and a sheath layer 7;

[0041] Between the conductor layer 1 and the sheath layer 7, from the inside out, there are a buffer shield layer 2, an insulation layer 3, an insulation shield layer 4, a braided reinforcement layer 5, and a buffer repair layer 6.

[0042] It should be noted that the buffer shielding layer 2 is the shielding structure of the conductor layer 1, and can also be called a filler layer, which is extruded from a highly thermally conductive flexible semiconductor.

[0043] Insulation layer 3, which provides the main insulation function for the cable, is made of cross-linked polyethylene extrusion;

[0044] Insulating shielding layer 4, which provides a homogenized electric field on the insulation surface of the cable, is extruded from carbon black blended semi-conductive polyethylene.

[0045] It should also be noted that the buffer shielding layer 2, the insulating layer 3, and the insulating shielding layer 4 are conventional technical means in this field, and will not be described in detail here.

[0046] Specifically, such as Figure 4 and Figure 5 As shown, conductor layer 1 includes a reinforcing core 11, conductor one 12, and conductor two 13;

[0047] Among them, the reinforcing core 11 is located at the center, and the conductor 12 is stranded in layers on the outer ring of the reinforcing core 11;

[0048] Furthermore, the outermost conductor 13 has a trapezoidal structure;

[0049] Conductor 2 13 includes an outer arc surface 131 and an inner arc surface 132, which are located on the outer and inner sides of the radial direction, respectively;

[0050] Conductor 2 13 also includes a side arc surface 133, which connects the outer arc surface 131 and the inner arc surface 132;

[0051] Both the outer arc surface 131 and the inner arc surface 132 are arc surface structures, which are used to increase the contact surface with the outer buffer shield layer 2 and the contact surface with the stranded coil of conductor-12, respectively.

[0052] It is understandable that the trapezoidal structure of conductor 213 can make the outer surface of the stranded coil more rounded, which can eliminate the large area gaps formed by the traditional circular structure braiding and achieve the effect of homogenizing the electric field.

[0053] The arc surfaces of the outer arc surface 131 and the side arc surface 133 can increase the contact area with the buffer shielding layer 2, thereby accelerating the radial conduction of heat when heat is generated, which helps to maintain the stability of the internal temperature of the conductor layer 1.

[0054] It should be noted that the reinforcing core 11 is a solid round rod structure made of high-temperature epoxy resin or high-performance polyimide resin.

[0055] Conductor 12 and conductor 23 are made of conventional round annealed copper wire;

[0056] The selection of materials for reinforcing core 11, conductor one 12 and conductor two 13 is a conventional technique in this field and will not be described in detail here.

[0057] Specifically, please refer to Figure 3 and Figure 5 as well as Figure 8 The braided reinforcement layer 5 includes an inner braided composite layer 52 and an outer braided layer 53, and also includes an anchoring unit 51 located at the intersection.

[0058] The inner braided composite layer 52 includes flat filaments 521 and round filaments 522. The flat filaments 521 are made of high-conductivity aluminum alloy, and the round filaments 522 are made of annealed copper. The two are arranged side by side and braided together to form a dense grid structure with a braiding angle of 30°±5°.

[0059] Furthermore, the outer braided layer 53 comprises yarns made by mixing and twisting multiple high-performance polyethylene fibers with a circular cross-section and nickel-titanium alloy, which are braided on the outside of the inner braided composite layer 52 to form a relatively loose mesh structure, with a braiding angle of 50°±5°.

[0060] Furthermore, the anchoring unit 51 includes a hot melt wire 511, which is made of a low melting point material with a melting point of 120℃-180℃. Multiple hot melt wires 511 form a group. The braiding of the inner braided composite layer 52 and the braiding of the outer braided layer 53 will form an intersection point. The anchoring unit 51 is inserted in the intersection point area. After hot melting, the anchoring unit 51 connects the inner braided composite layer 52 and the outer braided layer 53 to form an anchor.

[0061] It is understandable that the interlocking between the polymer fibers of the outer braided layer 53 and the anchoring unit 51 can quickly transmit the external impacts on the cable along the circumferential and axial directions, thereby dispersing stress to prevent it from concentrating in local areas. This not only enhances the resistance of the cable, but also improves the durability of the braided structure.

[0062] The thermal conductivity of the inner braided composite layer 52 enables rapid heat conduction when heat is generated in the central region of the cable and discharged radially outward, which can both promote radial discharge and form axial dispersion.

[0063] At the same time, when the discharged heat is conducted to the outer braided layer 53, it will cause the outer braided layer 53 to shrink and deform slightly, thereby increasing the gaps to promote the radial discharge of heat.

[0064] In addition, the anchoring unit 51 anchors the inner braided composite layer 52 and the outer braided layer 53, and can also maintain the interface connection between the inner and outer layers and maintain the integrity of the structure under different working conditions of the cable.

[0065] Specifically, please refer to Figure 3 and Figure 6 The buffer repair layer 6 includes a metal corrugated skeleton and a flexible coating 63;

[0066] The metal corrugated skeleton includes an outwardly convex corrugated section 61 and an inwardly concave corrugated section 62, both of which are annular aluminum alloy strips with circular arc cross sections. The outwardly convex corrugated section 61 and the inwardly concave corrugated section 62 are connected end to end in the axial direction to form a continuous undulating corrugated structure.

[0067] Furthermore, the flexible coating 63 is uniformly coated on the inner side of the metal corrugated skeleton, forming a filling part 631 in the annular space inside the convex corrugated section 61. The flexible coating 63 and the metal corrugated skeleton are connected and fixed by a primer.

[0068] Furthermore, the flexible coating 63 is made of flexible epoxy resin and has repair microcapsules 6301 densely distributed inside.

[0069] Repair microcapsules 6301 include low-viscosity siloxane repair agent microcapsules and curing agent microcapsules, which are used to fill cracks in adjacent structures to form an elastomer and achieve a self-healing effect.

[0070] In addition, the sheath layer 7 is made of polyurethane or modified PVC extruded on the outside of the metal corrugated skeleton, and the extruded material of the sheath layer 7 fills the annular space outside the concave corrugated section 62 to form an inner convex part 71.

[0071] Understandably, the corrugated metal skeleton is used to provide the main buffer function. Under the influence of working conditions such as frequent bending of the cable, the corrugated metal skeleton and the sheath layer 7 are vulnerable components. The flexible coating 63 distributed on the inner side forms a local filling of the cracks and gaps of the vulnerable components, thereby maintaining the stability of the structure and helping to improve the long-term performance of the cable.

[0072] It should be noted that since the flexible coating 63 and the metal corrugated skeleton are a firmly integrated structure, when the cable is subjected to impact and the convex corrugated section 61 breaks, the breaking force will also destroy the flexible coating 63, thereby releasing the repair microcapsules 6301. The two repair microcapsules 6301 undergo rapid cross-linking and curing at the gap to form an elastomer, achieving the effect of automatically and locally filling the gap, which can block the propagation path of the crack and restore insulation and waterproof properties.

[0073] It should also be noted that the sheath layer 7 is a conventional technical method in this field, and will not be described in detail here.

[0074] In some publicly available information, the braiding process for insulated power cables is specifically applied as follows:

[0075] Specifically, the weaving method for the reinforcing layer 5 is as follows:

[0076] S1. On the cable braiding production line, two braiding machines are arranged in series, which are the first braiding unit and the second braiding unit.

[0077] The first weaving unit weaves the inner weaving composite layer 52 by parallel flat filaments 521 and round filaments 522, and the second weaving unit weaves the outer weaving layer 53 on the outside of the inner weaving composite layer 52 by twisting round filaments 531.

[0078] S2. On the cable braiding production line, a vision control unit containing an encoder and a precision vision positioning system is arranged to identify the intersection point between the inner braided composite layer 52 and the outer braided layer 53 after the outer braiding layer 53 is braided.

[0079] S3. On the cable braiding production line, a wire feeding unit, a heat melting unit, and a cooling unit are arranged.

[0080] After the vision control unit identifies the braiding intersection of the inner braided composite layer 52 and the outer braided layer 53, the hot melt wire 511 is inserted into the intersection area through the wire feeding unit. Then, the hot melt unit sprays high temperature airflow onto the hot melt wire 511 to heat melt it, thereby connecting the intersection area of ​​the inner braided composite layer 52 and the outer braided layer 53 into one. Subsequently, the cooling unit sprays low temperature airflow to implement low temperature cooling to solidify the anchoring structure.

[0081] It should be noted that the melting points of the flat filaments 521 and round filaments 522 contained in the inner braided composite layer 52 are 660℃ and 1083℃, respectively. The melting points of the high-performance polyethylene fiber and nickel-titanium alloy contained in the round filament braid 531 are 144℃-152℃ and 1300℃, respectively. The melting point of the hot melt wire 511 that needs to be hot melted is 120℃-180℃.

[0082] It should also be noted that the temperature of the high-temperature gas flow ejected from the melting unit is 320°C, the jetting time is preferably 50-100ms, and the gas flow is concentrated and directly acts on the hot melt wire 511;

[0083] Understandably, the melting point of the hot melt wire 511 is much lower than that of the flat wire 521, the round wire 522, and the nickel-titanium alloy. The polyethylene fiber only contacts the intersection of the hot melt wire 511. At this time, the heat is quickly dispersed through the heat sink effect by the instantaneous energy output to the hot melt wire 511, thereby achieving precise hot melting of the hot melt wire 511 and maintaining the integrity of the adjacent structure.

[0084] S4. On the cable braiding production line, there are also traction units, distributed at the inlet and outlet of the braiding system, used to drive the cable to be pulled through the braiding system.

[0085] Based on the above method, it can be understood that by combining multiple units within the braiding system, the effect of coordinated preparation of the inner and outer layers of the cable's internal structure is achieved, avoiding the problem that traditional braiding methods can only braid and process layer by layer. This braiding system enables the coordinated operation of the cable's internal structure, effectively improving the stability and durability of the cable structure.

[0086] It should be noted that the equipment used in the weaving system and traction unit can be purchased directly from the market by those skilled in the art based on the working conditions, and therefore will not be described in detail here.

[0087] In the description of this specification, references to terms such as "an embodiment," "example," and "specific example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0088] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An insulated power cable, characterized by: Including the conductor layer (1); The outer side of the conductor layer (1) is provided with a buffer shield layer (2), an insulation layer (3), an insulation shield layer (4), a braided reinforcement layer (5), a buffer repair layer (6), and a sheath layer (7) layer by layer. The conductor layer (1) includes a reinforcing core (11) and a conductor one (12) on its outer side and a conductor two (13) on the outermost ring, wherein the cross section of the conductor two (13) is trapezoidal; The braided reinforcement layer (5) includes an inner braided composite layer (52) on the inside and an outer braided layer (53) on the outside, and an anchoring unit (51) is fixed at the intersection of the inner braided composite layer (52) and the outer braided layer (53). The buffer repair layer (6) includes a metal corrugated skeleton and a flexible coating (63) on its inner side.

2. The insulated power cable according to claim 1, characterized in that: The first conductor (12) is stranded on the outside of the reinforcing core (11), and the second conductor (13) is stranded on the outermost ring, including an outer arc surface (131), an inner arc surface (132), and a side arc surface (133).

3. The insulated power cable according to claim 2, characterized in that: The outer arc surface (131) is located on the outer side of the contact buffer shield layer (2), the inner arc surface (132) is located on the inner side of the contact conductor (12), and the side arc surface (133) connects the two sides of the outer arc surface (131) and the inner arc surface (132).

4. The insulated power cable according to claim 1, characterized in that: The inner braided composite layer (52) includes flat filaments (521) and round filaments (522), which are arranged in pairs as a group. The outer braided layer (53) includes round filament braids (531).

5. The insulated power cable according to claim 4, characterized in that: The anchoring unit (51) includes multiple hot melt wires (511) inserted into the intersection area of ​​the inner braided composite layer (52) and the outer braided layer (53).

6. The insulated power cable according to claim 1, characterized in that: The metal corrugated skeleton includes an outwardly convex corrugated section (61) and an inwardly concave corrugated section (62) connected end to end in the axial direction. The flexible coating (63) is applied to the inner side of the metal corrugated skeleton. The flexible coating (63) includes a filling portion (631) that fills the inner area of ​​the outwardly convex corrugated section (61).

7. The insulated power cable according to claim 6, characterized in that: The interior of the filling part (631) is densely distributed with repair microcapsules (6301).

8. The insulated power cable according to claim 6, characterized in that: The inner side of the sheath layer (7) is filled into the outer region of the concave corrugated section (62) to form an inner convex part (71).

9. A braiding process for insulated power cables, applied to the insulated power cables as described in any one of claims 1-8, characterized in that: The system includes a weaving system, and the specific weaving steps of the weaving system for the weaving reinforcement layer (5) are as follows: S1. On the cable braiding production line, the first braiding unit and the second braiding unit are arranged in series to braid the inner braided composite layer (52) and the outer braided layer (53) respectively. S2. On the cable braiding production line, a vision control unit is set up to identify the braiding intersection of the inner braided composite layer (52) and the outer braided layer (53); S3. On the cable braiding production line, a wire feeding unit, a heat melting unit, and a cooling unit are arranged. The visual control unit controls the wire feeding unit to insert the hot melt wire (511) into the intersection area, and then controls the hot melt unit to fuse the hot melt wire (511). Subsequently, the cooling unit implements low-temperature cooling to solidify the anchoring structure. S4. Traction units are also arranged on the cable braiding production line, distributed at the inlet and outlet of the braiding system.

10. The braiding process of the insulated power cable according to claim 9, characterized in that: The inner braided composite layer (52) contains flat filaments (521) and round filaments (522) with melting points of 660°C and 1083°C, respectively. The outer braided layer (53) contains round filament braids (531) with melting points of high-performance polyethylene fiber and nickel-titanium alloy of 144°C-152°C and 1300°C, respectively. The hot melt wire (511) has a melting point of 120°C-180°C. The hot melt unit sprays out a high-temperature gas flow at a temperature of 320°C. The spraying time is preferably 50-100ms. The gas flow is concentrated and directly acts on the hot melt wire (511).

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