Double-layer insulated overhead insulated cable

Abstract

The utility model relates to the technical field of overhead cables, in particular to a double-layer insulating overhead insulated cable, which comprises a stranded conductor, a plurality of insulating layers, a plurality of insulating layers and a plurality of insulating layers, and is characterized in that the stranded conductor is of a steel-cored aluminum stranded wire structure; the shielding layer is coated on the outer wall of the stranded conductor; the first insulating layer is extruded on the outer wall of the shielding layer; the reinforcing layer is arranged on the outer wall of the first insulating layer; and the second insulating layer is extruded on the outer wall of the reinforcing layer. According to the utility model, the three groups of aramid fiber tows in strip-shaped distribution are arranged between the two insulating layers and are distributed in a central symmetry manner, after the processing cable is laid, no matter which angle the cable is laid at, the part which is bent downwards due to gravity is mainly pulled by the aramid fiber tows, and the usage amount of the aramid fiber tows is originally smaller than that of the aramid fiber tows in a weaving and covering manner; the tensile effect is higher than that of a weaving covering mode, and the processing cost can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of overhead cables, in particular to a double-layer insulated overhead insulated cable. Background Art

[0002] Overhead power lines generally use multiple strands of bare wires, but in recent years, 10kV overhead power distribution lines in urban areas have gradually switched to overhead insulated wires. Operation has proven that it has many advantages, significantly reducing line faults, solving the conflict between lines and trees to a certain extent, reducing maintenance workload, and improving the safety and reliability of line status monitoring.

[0003] As shown in Patent Document 1, current overhead insulated cables use a double-layer structure of an aramid braided layer and an insulating layer to improve the weather resistance of insulation. However, aramid fibers are easily affected by ultraviolet rays and age, and the outer aramid braided layer must reach a certain thickness to prevent it from becoming loose due to damage. Therefore, its manufacturing cost is high.

[0004] Prior art literature:

[0005] Patent document 1CN106856113A A 10kV overhead insulated cable Utility Model Content

[0006] In view of the technical problems existing in the overhead cables in the prior art, the first aspect of the utility model proposes a double-layer insulated overhead insulated cable, comprising:

[0007] A stranded conductor, the stranded conductor comprising a conductor layer and an inner reinforcement layer;

[0008] A shielding layer, the shielding layer is coated on the outer wall of the twisted conductor;

[0009] A first insulating layer, extruded and wrapped around the outer wall of the shielding layer;

[0010] An outer reinforcement layer, arranged on an outer wall of the first insulating layer;

[0011] A second insulating layer, extruded and wrapped around the outer wall of the outer reinforcement layer;

[0012] Among them, the outer reinforcement layer includes a first reinforcement layer and a second reinforcement layer, the first reinforcement layer includes three aramid ribbons distributed parallel to the cable axis, and the three aramid ribbons are distributed symmetrically around the axis of the cable, and the second reinforcement layer includes an aramid wire braided layer, and the aramid wire braided layer is coated on the outside of the three aramid ribbons.

[0013] Preferably, the width of each of the aramid ribbons is less than 1 / 6 of the circumference of the outer periphery of the first insulating layer.

[0014] Preferably, the aramid ribbon comprises a plurality of aramid filament bundles extending in a direction parallel to the cable axis.

[0015] Preferably, the outer wall of the first insulating layer is provided with grooves, the grooves are distributed along the axial direction of the cable, and the aramid filament bundles are arranged in the grooves.

[0016] Preferably, the braiding density of the aramid fiber braided layer is less than 50%.

[0017] Preferably, the conductor layer includes an inner conductor and an outer conductor, the inner conductor includes a bundle of 1+6 first twisted conductor structures, the outer conductor includes six bundles of 1+6 second twisted conductor structures, the first twisted conductor structures and the second twisted conductor structures constitute a 1+6 complex twisted structure; a plurality of steel wires are provided between the inner conductor and the outer conductor to form an inner reinforcement layer.

[0018] Preferably, a filling strip is provided between the outer conductor and the shielding layer.

[0019] Preferably, the shielding layer is a braided shielding layer or a wrapped shielding layer.

[0020] Preferably, the shielding layer comprises a wrapped copper-plastic composite tape, and the wrapping overlap rate of the copper-plastic composite tape is 30-40%.

[0021] Preferably, the first insulating layer comprises a radiation cross-linked polyethylene insulating layer, and the second insulating layer comprises a polyvinyl chloride insulating layer.

[0022] Compared with the prior art, the advantages of the utility model are:

[0023] The utility model arranges three groups of aramid bundles distributed in a strip shape between two insulating layers, and the distribution is symmetrical in the center. After the processed cable is laid, no matter at which angle the cable is laid, the portion bent downward due to gravity is mainly supported by the aramid bundles. The amount of aramid bundles used is less than that of the braided covering method, and the tensile effect is also higher than that of the braided covering method, which can reduce the processing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are not intended to be drawn to scale. In the accompanying drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For the sake of clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the utility model will be described by way of example and with reference to the accompanying drawings, in which:

[0025] Figure 1 It is a structural schematic diagram of a double-layer insulated overhead insulated cable shown in the utility model;

[0026] Figure 2It is a schematic diagram of the distribution of aramid ribbons shown in the utility model. DETAILED DESCRIPTION

[0027] In order to better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0028] Combination Figure 1-2 As shown, the first aspect of the utility model proposes a double-layer insulated overhead insulated cable, including a twisted conductor, a shielding layer 4, a first insulating layer 5, an outer reinforcement layer 6 and a second insulating layer 7. In order to increase the tensile strength of the conductor, the twisted conductor is a steel core aluminum stranded wire structure, the shielding layer 4 is coated on the outer wall of the twisted conductor, the first insulating layer 5 is extruded on the outer wall of the shielding layer 4, the outer reinforcement layer 6 is arranged on the outer wall of the first insulating layer 5, and the second insulating layer 7 is extruded on the outer wall of the outer reinforcement layer 6.

[0029] The twisted conductors of the shielding layer 4 provide equipotential, avoid local discharge heating, reduce heat loss due to electrical conduction, and prolong the life of the first insulating layer 5. The first insulating layer 5 is a main insulating layer, which uses a radiation cross-linked polyethylene insulating layer, and the outer reinforcing layer 6 is used as a sheath, which is required to have better wear resistance and weather resistance. Optionally, the second insulating layer 7 uses a polyvinyl chloride insulating layer.

[0030] In an optional embodiment, the shielding layer 4 is a braided shielding layer or a wrapped shielding layer.

[0031] Specifically, the shielding layer 4 includes a wrapped copper-plastic composite tape, and the wrapping overlap rate of the copper-plastic composite tape is 30-40%. The cable core formed in this way is round and has good shielding performance and bending performance.

[0032] Furthermore, the outer reinforcement layer 6 is intended to increase the physical properties of the insulation layer. The outer reinforcement layer 6 includes a first reinforcement layer 61 and a second reinforcement layer 62. The first reinforcement layer 61 includes three aramid ribbons distributed parallel to the cable axis. The three aramid ribbons are distributed symmetrically around the axis of the cable. The second reinforcement layer 62 includes an aramid wire braided layer. The aramid wire braided layer is coated on the outside of the three aramid wires.

[0033] Combination Figure 2 As shown, in the circumferential direction of the cable, the area where the aramid ribbons are distributed is the tensile area 602, and the remaining area is the easily bendable area 601. When the tensile area 602 is deformed, the aramid bundles in the aramid ribbons mainly play a tensile role.

[0034] In this way, after the overhead cable is laid, no matter at what angle the cable is installed, the fall of the cable between the two supporting points is mainly supported by the aramid ribbon, which prevents the twisted conductor from being subjected to excessive tension. Therefore, the conductor can maintain its roundness and electrical properties, and is not easy to deform or break.

[0035] In a preferred embodiment, the width of each aramid ribbon is less than 1 / 6 of the circumference of the outer periphery of the first insulating layer 5. This can reduce the width of the aramid ribbon and avoid excessive use of the aramid ribbon.

[0036] Specifically, the aramid ribbon includes a plurality of aramid bundles parallel to the cable axis. Thus, these aramid bundles mainly play an axial tensile role, thereby preventing the twisted conductor from being subjected to large tensile forces during the laying and overhead operation of the cable.

[0037] In a preferred embodiment, the outer wall of the first insulating layer 5 is provided with grooves, which are distributed along the axial direction of the cable, and the aramid tow is arranged in the grooves. During the processing, the position of the aramid tow is easy to be positioned to ensure that the aramid tow is in a predetermined angle and range in the processed cable, which will affect whether the overhead aramid tow plays a key tensile role in the later stage.

[0038] Furthermore, in order to protect and limit the aramid yarn bundle, an aramid yarn braided layer is provided on the outer layer of the aramid yarn bundle. Optionally, the braiding density of the aramid yarn braided layer is less than 50%.

[0039] Furthermore, since there are many gaps in the double-twisted structure, the extrusion stress between the conductors can be reduced. In order to reduce the stress changes of the twisted conductors caused by external temperature changes or other factors during the overhead process, the twisted conductors adopt a double-twisted structure. Specifically, the twisted conductor includes a conductor layer 2 and an inner reinforcement layer 1, the conductor layer 2 includes an inner conductor and an outer conductor, the inner conductor includes a bundle of 1+6 first twisted conductor structures, the outer conductor includes six bundles of 1+6 second twisted conductor structures, and the first twisted conductor structure and the second twisted conductor structure constitute a 1+6 double-twisted structure.

[0040] Furthermore, a plurality of steel wires are provided between the inner conductor and the outer conductor to form an inner reinforcement layer 1. In this way, the tensile strength of the cable conductor structure is increased by the steel wires between the inner conductor and the outer conductor.

[0041] Preferably, a filling strip 3 is provided between the outer conductor and the shielding layer 4, so that the shielding layer 4 is wrapped more rounded.

[0042] In combination with the above embodiments, the utility model arranges three groups of aramid bundles with strip distribution between two insulating layers, and is distributed symmetrically in the center. After the processed cable is laid, no matter at which angle the cable is laid, the part that bends downward due to gravity is mainly supported by the aramid bundles, and the amount of aramid bundles used is less than that of the braided covering method, and the tensile effect is also higher than that of the braided covering method, which can reduce the processing cost.

[0043] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A double-layer insulated overhead insulated cable, characterized in that: include: A twisted conductor, comprising a conductor layer (2) and an inner reinforcement layer (1); A shielding layer (4), the shielding layer (4) being coated on the outer wall of the twisted conductor; A first insulating layer (5) is extruded onto the outer wall of the shielding layer (4); An outer reinforcement layer (6) is arranged on the outer wall of the first insulating layer (5); A second insulating layer (7) is extruded onto the outer wall of the outer reinforcement layer (6); The outer reinforcement layer (6) comprises a first reinforcement layer (61) and a second reinforcement layer (62), wherein the first reinforcement layer (61) comprises three aramid ribbons distributed parallel to the cable axis, and the three aramid ribbons are distributed symmetrically around the cable axis, and the second reinforcement layer (62) comprises an aramid wire braided layer, and the aramid wire braided layer is coated on the outside of the three aramid wires.

2. The double-layer insulated overhead insulated cable according to claim 1, characterized in that: The width of each of the aramid ribbons is less than 1 / 6 of the circumference of the outer periphery of the first insulating layer (5).

3. The double-layer insulated overhead insulated cable according to claim 1, characterized in that: The aramid ribbon comprises a plurality of aramid filament bundles extending in a direction parallel to the cable axis.

4. The double-layer insulated overhead insulated cable according to claim 3, characterized in that: The outer wall of the first insulating layer (5) is provided with grooves, the grooves are distributed along the axial direction of the cable, and the aramid fiber bundles are arranged in the grooves.

5. The double-layer insulated overhead insulated cable according to claim 1, characterized in that: The braiding density of the aramid fiber braided layer is less than 50%.

6. The double-layer insulated overhead insulated cable according to claim 1, characterized in that: The conductor layer (2) comprises an inner conductor and an outer conductor, the inner conductor comprising a bundle of 1+6 first twisted conductor structures, the outer conductor comprising six bundles of 1+6 second twisted conductor structures, the first twisted conductor structures and the second twisted conductor structures forming a 1+6 multi-twisted structure; a plurality of steel wires are arranged between the inner conductor and the outer conductor to form an inner reinforcement layer (1).

7. The double-layer insulated overhead insulated cable according to claim 6, characterized in that: A filling strip (3) is provided between the outer conductor and the shielding layer (4).

8. The double-layer insulated overhead insulated cable according to claim 1, characterized in that: The shielding layer (4) is a braided shielding layer or a wrapped shielding layer.

9. The double-layer insulated overhead insulated cable according to claim 8, characterized in that: The shielding layer (4) comprises a wrapped copper-plastic composite tape, and the wrapping overlap rate of the copper-plastic composite tape is 30-40%.

10. The double-layer insulated overhead insulated cable according to claim 1, characterized in that: The first insulating layer (5) comprises a radiation cross-linked polyethylene insulating layer, and the second insulating layer (7) comprises a polyvinyl chloride insulating layer.

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