High-strength XLPE insulating temperature-resistant flame-retardant low-voltage power cable

Abstract

The utility model relates to the technical field of wires and cables, in particular to a high-strength XLPE (cross linked polyethylene) insulated temperature-resistant flame-retardant low-voltage power cable, which comprises a support structure, a plurality of cable cores and a plurality of cross linked polyethylene cable cores, the plurality of wire cores are arranged in the recesses of the supporting structure; the mica tape wraps the outer sides of the plurality of wire cores and the supporting structure and is fixed to form a cable core with a circular cross section; and the inner sheath is extruded on the outer side of the mica tape. According to the utility model, the supporting structures are arranged among the wire cores, each wire core is supported and separated through the supporting structures, the whole supporting structure adopts a cross-linked polyethylene foaming structure, and the surface of the supporting structure is provided with a flame-retardant coating, so that two adjacent wire cores can be effectively separated, and the cable is light in overall weight and good in flame retardance; the supporting structure can form a carbonized shell during combustion, so that transmission of open fire among the wire cores is prevented, and the risk of short-circuit current generated among the wire cores due to insulation aging of the wire cores is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of wire and cable, in particular to a high-strength XLPE insulated, temperature-resistant, flame-retardant low-voltage power cable. Background Art

[0002] According to different voltage levels, power cables are usually divided into extra-high voltage and ultra-high voltage cables (above 110 kV), high-voltage cables (35 - 110 kV), medium-voltage cables (3 - 35 kV), and low-voltage cables (0.6 / 1 kV). Extra-high voltage and ultra-high voltage cables are respectively used for main transmission lines (such as extra-high voltage and ultra-high voltage power grids), especially overhead transmission lines. High-voltage cables (35 - 110 kV) are suitable for high-voltage and ultra-high voltage power transmission and distribution lines and can be laid in tunnels or pipelines. Medium-voltage cables (3 - 35 kV) are usually suitable for scenarios such as urban distribution systems, underground utility tunnels, and industrial electricity use. Low-voltage cables (0.6 / 1 kV) are the most widely used power cables and can be laid indoors, outdoors, in pipelines, and cable trenches. They are used as a medium for power transmission and distribution in the fields of construction, industry, transportation, and municipal administration. For example, they are used for electrical power distribution in buildings to achieve lighting, equipment power supply, sockets, switches, safety control equipment, etc. in homes, apartments, hospitals, hotels, and shopping malls; in the industrial field, they are used for direct power supply to motors and machines; in the public transportation field, they are used for power supply to urban rail transit and tram stations, such as electrical facilities in subway stations, tram tracks, and bus stations.

[0003] In public places, fires caused by the ignition of gas lines are usually due to various factors. Especially for cables that have been used for a long time, the reasons for cable ignition include sheath aging, insulation aging, high-temperature aging, waterproof penetration layer, etc., which lead to damage, cracking, or insulation failure of the insulation layer, as well as overload of the cable, resulting in short circuit or discharge between cable cores, and finally causing a fire. Currently, the flame-retardant structure of low-voltage cables usually fills flame-retardant ropes (PP, polyurethane, glass fiber, etc.) between cables, and wraps flame-retardant tapes outside the cable cores, which can effectively prevent the continuous combustion of the cable and inhibit the spread of open flames. However, the cable structure is dense, heavy, and costly. Summary of the Invention

[0004] In view of the technical problems existing in low-voltage cables in the prior art, the first aspect of the utility model provides a high-strength and lightweight XLPE insulated, temperature-resistant, flame-retardant low-voltage power cable, comprising:

[0005] A support structure provided with a plurality of cavities for accommodating wire cores;

[0006] A plurality of wire cores arranged in the cavities of the support structure;

[0007] Mica tape wrapped around the plurality of wire cores and the outside of the support structure and solidified into a cable core with a circular cross-section;

[0008] An inner sheath, extruded on the outer side of the mica tape;

[0009] A flame-retardant wrapping layer, wrapped on the outer side of the inner sheath;

[0010] An outer sheath, extruded on the outer side of the flame-retardant wrapping layer;

[0011] Wherein, the support structure is a cross-linked polyethylene foam structure, the support structure is configured as a strip extending along the length direction of the cable, and each two of the cores are separated by the support structure, and a separate enclosed space is formed between the recess and the mica tape, and a single core is located in the enclosed space.

[0012] Preferably, the support structure includes a main body structure and a partition structure connected to the main body structure. In any cross-section of the cable, the partition structure is distributed in a circumferential array around the main body structure.

[0013] Preferably, the main body structure and two adjacent partition structures together form the recess.

[0014] Preferably, the main body structure is configured to have an arcuate concave surface on its surface, the concave surface fits the surface of the core, and the partition structure extends outward along the tangent direction of the core.

[0015] Preferably, the surfaces of the main body structure and the partition structure are provided with a flame-retardant coating, and the flame-retardant coating includes an organic flame retardant coating or an inorganic flame retardant coating.

[0016] It is usually used with a thickness of 0.07 - 0.20 mm.

[0017] Preferably, the core includes a stranded conductor, an inner wrapping tape layer, and an insulating layer. The inner wrapping tape layer is wrapped on the outer layer of the stranded conductor, and the insulating layer is extruded on the outer layer of the inner wrapping tape layer.

[0018] Preferably, the insulating layer includes a cross-linked polyethylene insulating layer.

[0019] Preferably, the inner sheath includes a cross-linked polyethylene insulating layer, the flame-retardant wrapping layer includes a glass fiber tape wrapping layer, and the outer sheath includes a low-smoke and halogen-free polyolefin sheath structure.

[0020] Preferably, a flame-retardant strip is filled in the gap between the core and the mica tape. The flame-retardant strip includes a cross-linked polyethylene foam strip, and a flame-retardant coating is provided on the surface of the cross-linked polyethylene foam strip.

[0021] Compared with the prior art, the remarkable advantages of the high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable of the present utility model are as follows:

[0022] In the design of the high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable proposed by the present utility model, a support structure is provided between each core. Each core is supported and separated by the support structure. The overall support structure uses a cross-linked polyethylene foam structure, and a flame-retardant coating is provided on the surface, which can effectively separate two adjacent cores. The overall quality of the cable is light and the flame retardancy is good. When the core heats up and burns, the support structure can form a carbonized shell during combustion to prevent the spread of open flames between the cores and reduce the risk of short-circuit current generated between the cores due to the insulation aging of the cores. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings are not intended to be drawn to scale. In the drawings, each identical or approximately identical component shown in each figure may be denoted by the same reference numeral.

[0024] Figure 1 is a schematic structural diagram of the high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable shown by the present utility model.

[0025] Figure 2 is a schematic cross-sectional structural diagram of the high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable shown by the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] In order to better understand the technical content of the present utility model, specific embodiments are hereby given and described in conjunction with the accompanying drawings as follows.

[0027] As Figure 1 and Figure 2 shown, the high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable proposed in the first aspect of the present utility model includes a cable core, a flame-retardant structure, and a sheath. The cable core is composed of a support structure 1, multiple cores 2, and mica tape 3.

[0028] The support structure 1 is provided with a plurality of cavities for accommodating the cores 2. The multiple cores 2 are arranged in the cavities of the support structure 1. The mica tape 3 is wound around the multiple cores 2 and the outer side of the support structure 1 and is shaped into a cable core with a circular cross-section.

[0029] Since each adjacent core 2 is isolated by the support structure 1, the risk of short-circuit current generated between the cores 2 due to the insulation aging of the cores 2 can be reduced.

[0030] Furthermore, the support structure 1 is a cross-linked polyethylene foam structure. The support structure 1 is configured as a strip extending along the length direction of the cable. Each two cores 2 are separated by the support structure 1. A separate enclosed space is formed between the cavity and the mica tape 3, and a single core 2 is located in the enclosed space.

[0031] Thus, the support structure 1 adopts a cross-linked polyethylene foam structure, which has good insulation performance, buffering performance, heat insulation and heat preservation performance, as well as weather resistance and aging resistance, and can play a good role in separating the adjacent cores 2 in the recesses.

[0032] As Figure 1 shown, the support structure 1 includes a main body structure 11 and a partition structure 12 connected to the main body structure 11. In any cross-section of the cable, the partition structure 12 is arranged in a circumferential array around the main body structure 11.

[0033] Among them, the main body structure 11 is constructed as a strip with a polyhedron cross-section, each face corresponding to a core 2, and each face is preferably an arc-shaped concave surface, which is beneficial to the fitting of the concave surface with the surface of the core 2. Further, the partition structure 12 extends outward along the tangent direction of the core 2. Thus, each core 2 in the recess is separated by the partition structure 12.

[0034] It should be understood that the main body structure 11 and two adjacent partition structures 12 together form a recess.

[0035] Further, the surfaces of the main body structure 11 and the partition structure 12 are provided with a flame retardant coating 13, and the flame retardant coating 13 includes an organic flame retardant coating or an inorganic flame retardant coating.

[0036] Thus, the flame retardant performance of the support structure 1 can be further improved by the provided flame retardant coating 13. The organic flame retardant coating or the inorganic flame retardant coating can be adhered to the surfaces of the main body structure 11 and the partition structure 12 by mixing adhesives. The organic flame retardant can be selected as red phosphorus flame retardant, and the inorganic flame retardant can be selected as aluminum hydroxide flame retardant. A glue adhesive of a mixed flame retardant is formed by mixing with epoxy resin, curing agent and additives.

[0037] Once the core 2 catches fire and burns, the flame retardant can quickly absorb heat when heated, and form a carbonized layer relying on the partition structure 12 at high temperature, playing a role in separating and flame retarding the adjacent core 2, and preventing the cable from continuous burning after catching fire.

[0038] Preferably, the thickness of the partition structure 12 is 0.7 - 2.0 mm, and the thickness of the flame retardant coating 13 on the surface of the partition structure 12 is 0.07 - 0.20 mm.

[0039] Furthermore, a flame retardant strip is filled in the gap between the core 2 and the mica tape 3. The flame retardant strip includes a cross-linked polyethylene foam strip, and the above-mentioned flame retardant coating is provided on the surface of the cross-linked polyethylene foam strip.

[0040] Further, the core 2 includes a stranded conductor 21, an inner wrapped tape layer 22 and an insulating layer 23. The inner wrapped tape layer 22 is coated on the outer layer of the stranded conductor 21, and the insulating layer 23 is extruded on the outer layer of the inner wrapped tape layer 22.

[0041] Among them, the inner wrapping tape layer 22 is wrapped with mica tape, and the wrapping overlapping rate is controlled to be 20% - 30%. The insulating layer 23 includes a cross-linked polyethylene insulating layer.

[0042] Furthermore, the inner sheath 4 is extruded on the outer side of the mica tape 3, the flame-retardant wrapping layer 5 is wrapped on the outer side of the inner sheath 4, and the outer sheath 6 is extruded on the outer side of the flame-retardant wrapping layer 5.

[0043] Among them, the inner sheath 4 can be selected as a cross-linked polyethylene insulating layer, the flame-retardant wrapping layer 5 can be selected as a glass fiber tape wrapping layer, the number of layers of the glass fiber tape wrapping layer is 2 - 3 layers, the wrapping overlapping rate is 40% - 50%, and the outer sheath 6 includes a low-smoke and halogen-free polyolefin sheath structure.

[0044] In this way, by using the cross-linked polyethylene insulating layer, the weight of the cable can be reduced as a whole. At the same time, through the separation effect on the wire cores, the potential safety hazard of short circuit between cables can be reduced.

[0045] Combined with the above embodiments, for the high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable of the present invention, by arranging a support structure between each wire core, each wire core is supported and separated by the support structure. The support structure as a whole uses a cross-linked polyethylene foam structure and is provided with a flame-retardant coating on the surface, which can effectively separate two adjacent wire cores. The overall quality of the cable is light and the flame retardancy is good. When the wire core catches fire and burns, the support structure can form a carbonized shell during combustion, preventing the open fire from spreading between the wire cores and reducing the risk of short-circuit current generated between the wire cores due to the insulation aging of the wire cores, thereby improving the reliability and safety of cable laying and long-term use.

[0046] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to what is defined by the claims.

Claims

1. A high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable, characterized in that, Comprising: A support structure (1) provided with a plurality of cavities for accommodating the wire cores (2); A plurality of wire cores (2) arranged in the cavities of the support structure (1); A mica tape (3) wound around the outside of the plurality of wire cores (2) and the support structure (1) and solidified into a cable core with a circular cross-section; An inner sheath (4) extruded on the outside of the mica tape (3); A flame-retardant wrapping layer (5) covering the outside of the inner sheath (4); An outer sheath (6) extruded on the outside of the flame-retardant wrapping layer (5); Wherein, the support structure (1) is a cross-linked polyethylene foamed structure, the support structure (1) is constructed as a strip extending along the cable length direction, each two wire cores (2) are separated by the support structure (1), a separate closed space is formed between the cavity and the mica tape (3), and a single wire core (2) is located in the closed space.

2. The high-strength XLPE insulated temperature-resistant and flame-retardant low-voltage power cable according to claim 1, wherein The support structure (1) includes a main body structure (11) and a partition structure (12) connected to the main body structure (11), and in any cross-section of the cable, the partition structure (12) is distributed in a circumferential array around the main body structure (11).

3. The high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable according to claim 2, wherein The main body structure (11) and two adjacent partition structures (12) together form the cavity.

4. The high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable according to claim 2, wherein The main body structure (11) is constructed to have an arcuate concave surface on its surface, the concave surface fits the surface of the wire core (2), and the partition structure (12) extends outward along the tangent direction of the wire core (2).

5. The high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable according to claim 2 or 3 or 4, characterized in that, The surfaces of the main body structure (11) and the partition structure (12) are provided with a flame-retardant coating (13), and the flame-retardant coating (13) includes an organic flame-retardant coating or an inorganic flame-retardant coating.

6. The high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable according to claim 5, characterized in that, The thickness of the partition structure (12) is 0.7 - 2.0 mm, and the thickness of the flame-retardant coating (13) on the surface of the partition structure (12) is 0.07 - 0.20 mm.

7. The high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable according to claim 1, characterized in that, The wire core (2) includes a stranded conductor (21), an inner wrapping tape layer (22), and an insulating layer (23), the inner wrapping tape layer (22) covers the outer layer of the stranded conductor (21), and the insulating layer (23) is extruded on the outer layer of the inner wrapping tape layer (22).

8. The high-strength XLPE insulated temperature-resistant and flame-retardant low-voltage power cable according to claim 7, wherein The insulating layer (23) includes a cross-linked polyethylene insulating layer.

9. The high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable according to claim 1, wherein, The inner sheath (4) includes a cross-linked polyethylene insulating layer, the flame-retardant wrapping layer (5) includes a glass fiber tape wrapping layer, and the outer sheath (6) includes a low-smoke and halogen-free polyolefin sheath structure.

10. The high-strength XLPE-insulated temperature-resistant and flame-retardant low-voltage power cable according to claim 1, characterized in that, A flame-retardant strip is filled in the gap between the wire core (2) and the mica tape (3), the flame-retardant strip includes a cross-linked polyethylene foamed strip, and a flame-retardant coating is provided on the surface of the cross-linked polyethylene foamed strip.

Images