Halogen-free low-smoke flame-retardant single-core fireproof medium-voltage cable

Abstract

The utility model discloses a halogen-free low-smoke flame-retardant single-core fire-resistant medium-voltage cable, which belongs to the field of power cables and comprises an insulation shielding wire core, and the insulation shielding wire core comprises a conductor, a fire-resistant layer, a conductor shielding layer, an insulation layer, an insulation shielding layer, a heat insulation layer and a metal shielding layer which are sequentially arranged from inside to outside. A fire retardant layer, an inner protection flame retardant layer, a metal armor layer, a fire blocking layer and an outer protection layer are sequentially arranged on the outer side of the insulation shielding wire core from inside to outside. According to the utility model, by adopting the structural design of the fire-resistant layer, the fire-retardant layer and the fire-blocking layer, the fire-resistant temperature is obviously improved, the cable has the characteristics of flame retardance, fire resistance, no halogen, low smoke, low toxicity, low heat release and the like, the heat dissipation of the conductor can be promoted in an optimized scheme, and the cable is particularly suitable for civil facilities and industrial device power transmission and distribution grids with rated voltage of 3.6 / 6kV-26 / 35kV to realize electric energy transmission.

Description

Technical Field

[0001] The utility model mainly relates to the field of power cables, in particular to a halogen-free, low-smoke, flame-retardant, single-core, fire-resistant medium-voltage cable. Background Art

[0002] Since power cables need to pass through buildings and relatively densely populated areas, and power cables in these areas are more prone to power accidents due to the influence of complex natural factors, in order to prevent power accidents from causing fires, or to prevent power cables from causing secondary accidents when damaged by fire, power cables are required to have reliable fire resistance and environmental protection performance.

[0003] Currently, low-voltage (1kV) fire-resistant power cables have corresponding national standards, which are relatively mature. However, medium-voltage fire-resistant power cables, with their high voltage ratings and safety requirements, have less mature application standards and no unified national standards. Patent publication number CN 212934207 U discloses a medium-voltage single-core DC fire-resistant cable, comprising a conductor, which is then protected by an inner shield, an insulation layer, an outer shield, a semi-conductive buffer water-blocking tape, a halogen-free, low-smoke, high-flame-retardant tape, an inner sheath, a ceramic silicone rubber tape, a glass fiber tape, an oxygen barrier layer, and an outer sheath. This solution utilizes halogen-free, low-smoke, flame-retardant polyolefin for the inner and outer sheaths and oxygen barrier layers, which are halogen-free and environmentally friendly. Furthermore, the cable's fire-resistant properties are ensured by the use of multiple layers of fire-resistant materials. This multi-layered fire-resistant structure prevents flame spread and dripping in the event of a fire, while also forming a hard ceramic armor, ensuring the cable's fire resistance. However, single-core medium-voltage cables, including the aforementioned single-core DC fire-resistant cables, primarily only achieve fire resistance and flame resistance on the outer core. Their fire-resistant and flame-retardant structures and performance need to be improved. Furthermore, single-core cables have a larger conductor cross-section, requiring optimized heat dissipation. Utility Model Content

[0004] The technical solution of the utility model is aimed at the technical problem that the existing technical solution is too single, and provides a solution that is significantly different from the existing technology. It mainly provides a halogen-free low-smoke flame-retardant single-core fire-resistant medium-voltage cable to solve the technical problems raised in the above background technology that the fire-resistant and flame-retardant structure of the existing single-core medium-voltage cable needs to be improved, and the fire-resistant and flame-retardant performance needs to be improved.

[0005] The technical solution adopted by the utility model to solve the above technical problems is:

[0006] A halogen-free, low-smoke, flame-retardant, single-core, fire-resistant medium-voltage cable comprises an insulated shielded wire core, which comprises a conductor, a fire-resistant layer, a conductor shielding layer, an insulating layer, an insulating shielding layer, a thermal insulation layer, and a metal shielding layer, which are sequentially arranged from the inside to the outside; and a fire-blocking layer, an inner flame-retardant layer, a metal armor layer, a fire-blocking layer, and an outer protective layer, which are sequentially arranged on the outside of the insulated shielded wire core from the inside to the outside.

[0007] Furthermore, a fire-resistant protective layer is provided between the fire-resistant layer and the conductor shielding layer.

[0008] Preferably, the conductor is made of aluminum alloy monofilaments or copper monofilaments twisted in a regular manner, and the diameter of the aluminum alloy monofilaments or copper monofilaments is 2.53-2.54 mm; the fire-resistant layer is made of double-layer synthetic mica tape wrapped, and the wrapping coverage rate is 20%-25%.

[0009] Preferably, the fire-resistant protective layer is formed by wrapping a single layer of overlapping mesh glass fiber tape, with an overlap rate of 15%-20%.

[0010] Preferably, the thermal insulation layer is formed by wrapping a single layer of overlapping mesh glass fiber tape, with an overlap rate of 15%-20%.

[0011] Preferably, the fire barrier layer is formed by wrapping a double layer of overlapping alkali-free glass fiber tape, with an overlap rate of 15%-20%.

[0012] Preferably, the inner flame-retardant layer is made of a PTFE sheath material with high fire resistance.

[0013] Preferably, the fire barrier layer is formed by wrapping double-layer overlapping synthetic mica tape with a wrapping coverage rate of 15%-20%; the outer protective layer is made of low-smoke halogen-free flame-retardant polyolefin sheath material with an oxygen index of 35%.

[0014] Furthermore, the conductor includes a split conductor, which includes a plurality of conductor strand blocks arranged along the circumferential direction, and each adjacent two conductor strand blocks are separated by an insulating component, and the insulating component includes two insulating layers respectively contacting the two adjacent conductor strand blocks and a heat-conducting layer located between the two insulating layers.

[0015] Furthermore, the heat-conducting layer includes at least two parts sequentially arranged along a direction extending outward from the center of the conductor, and the thermal conductivity of the materials thereof increases in sequence according to the aforementioned order.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] This cable utilizes a fire-resistant structure combining a fire-resistant layer, a fire-blocking layer, and a fire-retardant layer. The fire-resistant layer contacts the conductor surface for specialized protection, the fire-blocking layer contacts the core surface for specialized protection, and the fire-blocking layer contacts the inner side of the outer sheath for fire-resistant protection of the cable body, forming a multi-layer fire-resistant and flame-retardant structure. The cable's fire-resistant protective layer, thermal insulation layer, inner flame-retardant layer, and outer sheath (sheathed in a low-smoke, halogen-free, flame-retardant polyolefin material) further enhance its fire resistance and flame-retardant properties. The cable boasts a long-term fire resistance temperature of 1200°C to 1300°C, preventing and isolating flames from propagating internally, ensuring long-term power operation in the event of a fire. Its flame-retardant, fire-resistant, halogen-free, low-smoke, low-toxicity, and low-heat release properties significantly reduce casualties from smoke emissions during fires. It is particularly suitable for power transmission in distribution networks for residential and industrial installations with rated voltages of 3.6 / 6kV to 26 / 35kV.

[0018] In the optimized solution of the present invention, the conductor adopts a split conductor, and a heat-conducting layer is introduced into the insulating member between two adjacent conductor strands, so as to facilitate the heat dissipation of the conductor center to the outside, thereby promoting the heat dissipation of the conductor.

[0019] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the cross-sectional structure of the utility model in Example 1;

[0021] Figure 2 This is a schematic diagram of the cross-sectional structure of the conductor in the second embodiment of the present utility model;

[0022] Figure 3 for Figure 2 Schematic diagram of the enlarged structure of area A in the middle.

[0023] Figure numerals: 1. conductor; 101. conductor strand block; 102. thermal conductive layer; 103. insulating barrier; 2. fire-resistant layer; 3. fire-resistant protective layer; 4. conductor shielding layer; 5. insulating layer; 6. insulating shielding layer; 7. thermal insulation layer; 8. metal shielding layer; 9. fire barrier layer; 10. inner flame retardant layer; 11. metal armor layer; 12. fire barrier layer; 13. outer protective layer. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings, but the present invention can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the content disclosed in the present invention more thorough and comprehensive.

[0025] Example 1: A halogen-free low-smoke flame-retardant single-core fire-resistant medium-voltage cable. Please refer to the attached Figure 1 , including an insulated shielded wire core, which is composed of a conductor 1, a fire-resistant layer 2, a fire-resistant protective layer 3, a conductor shielding layer 4, an insulating layer 5, an insulating shielding layer 6, a thermal insulation layer 7, and a metal shielding layer 8, which are arranged in sequence from the inside to the outside. The outside of the insulated shielded wire core is provided with a fire-blocking layer 9, an inner flame-retardant layer 10, a metal armor layer 11, a fire-blocking layer 12, and an outer protective layer 13 in sequence from the inside to the outside.

[0026] Conductor 1 is made of aluminum alloy monofilaments in a regular twisted pattern (using a 1+6+12+18+... structure with adjacent layers twisted in opposite directions and the outermost layer twisted to the left), and the diameter of the aluminum alloy monofilament is 2.53 mm.

[0027] The fire-resistant layer 2 is formed by wrapping double layers of synthetic mica tape, with a wrapping coverage rate of 20%.

[0028] The fire-resistant protective layer 3 is formed by wrapping a single layer of overlapping mesh glass fiber tape, with an overlap rate of 15%.

[0029] The conductor shielding layer 4 is made of semi-conductive high-voltage cross-linked material; the insulating layer 5 is made of cross-linked polyethylene; the insulating shielding layer 6 is made of semi-conductive high-voltage cross-linked material and is extruded through a dry cross-linking three-layer co-extrusion device.

[0030] The heat insulation layer 7 is formed by wrapping a single layer of overlapping mesh glass fiber tape, with an overlap rate of 20%;

[0031] The metal shielding layer 8 is formed by overlapping copper tapes, with an overlap rate of 15%;

[0032] The fire barrier layer 9 is made of double-layer overlapping wrapped alkali-free glass fiber tape, with a wrapping coverage rate of 20%;

[0033] The inner flame retardant layer 10 is made of a PTFE (polytetrafluoroethylene) sheath material with high fire resistance, extruded by an extruder, and has excellent flame retardancy and fire resistance.

[0034] The metal armor layer 11 is formed by wrapping a double-layer gap-wrap stainless steel tape, with a wrapping gap ratio of 45%;

[0035] The fire barrier layer 12 is formed by wrapping double-layer overlapping synthetic mica tape, with a wrapping coverage rate of 20%;

[0036] The outer sheath 13 is made of a low-smoke, halogen-free, flame-retardant polyolefin sheath material with an oxygen index of 35%, extruded by an extruder, and has excellent environmental protection and flame-retardant properties.

[0037] Example 2: This example differs from Example 1 in that:

[0038] Conductor 1 is made of copper monofilaments in a regular twisted pattern (using a 1+6+12+18+... structure with adjacent layers twisted in opposite directions and the outermost layer twisted to the left), and the diameter of the copper monofilament is 2.54 mm.

[0039] The fire-resistant layer 2 is formed by wrapping double layers of synthetic mica tape, with a wrapping coverage rate of 25%.

[0040] The fire-resistant protective layer 3 is formed by wrapping a single layer of overlapping mesh glass fiber tape, with an overlap rate of 20%.

[0041] The conductor shielding layer 4 is made of semi-conductive high-voltage cross-linked material; the insulating layer 5 is made of cross-linked polyethylene; the insulating shielding layer 6 is made of semi-conductive high-voltage cross-linked material and is extruded through a dry cross-linking three-layer co-extrusion device.

[0042] The heat insulation layer 7 is formed by wrapping a single layer of overlapping mesh glass fiber tape, with an overlap rate of 20%;

[0043] The metal shielding layer 8 is formed by overlapping copper tapes, with an overlap rate of 20%;

[0044] The fire barrier layer 9 is made of double-layer overlapping wrapped alkali-free glass fiber tape, with a wrapping coverage rate of 15%;

[0045] The inner flame retardant layer 10 is made of a PTFE (polytetrafluoroethylene) sheath material with high fire resistance, extruded by an extruder, and has excellent flame retardancy and fire resistance.

[0046] The metal armor layer 11 is formed by wrapping a double-layer gap-wrap stainless steel tape, with a wrapping gap ratio of 45%;

[0047] The fire barrier layer 12 is formed by wrapping double-layer overlapping synthetic mica tape, with a wrapping coverage rate of 15%;

[0048] The outer sheath 13 is made of a low-smoke, halogen-free, flame-retardant polyolefin sheath material with an oxygen index of 35%, extruded by an extruder, and has excellent environmental protection and flame-retardant properties.

[0049] Other details are the same as those in the first embodiment.

[0050] Example 3: This example differs from Example 1 in that:

[0051] Please refer to the attached Figure 2The conductor 1 includes a split conductor, and the conductor 1 includes a plurality of conductor strand blocks 101 arranged along the circumferential direction, and each adjacent two conductor strand blocks 101 are separated by an insulating member. The split conductor structure can effectively reduce the influence of the skin effect on the AC resistance of the conductor, thereby improving the current carrying capacity of the cable. In addition, this structure can also reduce the loss and heat generation of the cable, and improve the operating efficiency and reliability of the cable. Especially for single-core cables, compared with multi-core cables, the conductor cross-section of single-core cables is larger. The use of a split conductor design can more effectively utilize the surface area of ​​the conductor and improve the overall conductive performance.

[0052] Conductor 1 is made of aluminum alloy monofilaments in a regular twisted pattern (using a 1+6+12+18+... structure with adjacent layers twisted in opposite directions and the outermost layer twisted to the left), and the diameter of the aluminum alloy monofilament is 2.53 mm.

[0053] The fire-resistant layer 2 is formed by wrapping double layers of synthetic mica tape, with a wrapping coverage rate of 20%.

[0054] The fire-resistant protective layer 3 is formed by wrapping a single layer of overlapping mesh glass fiber tape, with an overlap rate of 20%.

[0055] The conductor shielding layer 4 is made of semi-conductive high-voltage cross-linked material; the insulating layer 5 is made of cross-linked polyethylene; the insulating shielding layer 6 is made of semi-conductive high-voltage cross-linked material and is extruded through a dry cross-linking three-layer co-extrusion device.

[0056] The thermal insulation layer 7 is formed by wrapping a single layer of overlapping mesh glass fiber tape, with an overlap rate of 15%;

[0057] The metal shielding layer 8 is formed by wrapping overlapping copper tapes, with an overlap rate of 25%;

[0058] The fire barrier layer 9 is made of double-layer overlapping wrapped alkali-free glass fiber tape, with a wrapping coverage rate of 15%;

[0059] The inner flame retardant layer 10 is made of a PTFE (polytetrafluoroethylene) sheath material with high fire resistance, extruded by an extruder, and has excellent flame retardancy and fire resistance.

[0060] The metal armor layer 11 is formed by wrapping a double-layer gap-wrap stainless steel tape, with a wrapping gap ratio of 50%;

[0061] The fire barrier layer 12 is formed by wrapping double-layer overlapping synthetic mica tape, with a wrapping coverage rate of 15%;

[0062] The outer sheath 13 is made of a low-smoke, halogen-free, flame-retardant polyolefin sheath material with an oxygen index of 35%, extruded by an extruder, and has excellent environmental protection and flame-retardant properties.

[0063] Other details are the same as those in the first embodiment.

[0064] Example 4: This example differs from Example 3 in that:

[0065] Please refer to the attached Figure 2 and attached Figure 3 The insulating member includes two insulating layers 103 (which can be made of insulating crepe paper) that contact two adjacent conductor strands 101, respectively, and a thermally conductive layer 102 located between the two insulating layers 103. The provision of the thermally conductive layer 102 facilitates the outward dissipation of heat from the center of the conductor 1, thereby promoting heat dissipation from the conductor 1. The insulating layers 103 provide insulation and isolation between the two adjacent conductor strands 101. Since materials with good thermal conductivity generally also have good electrical conductivity, the two insulating layers 103 are used to separate the thermally conductive layer 102 and the conductor strands 101 to avoid affecting the effectiveness of the insulating member.

[0066] Other aspects are the same as those of Example 3.

[0067] Example 5: This example differs from Example 4 in that:

[0068] The thermally conductive layer 102 comprises at least two portions arranged sequentially along the direction extending outward from the center of the conductor 1, and the thermal conductivity of the materials used for these portions increases in the aforementioned order (for example, at least two of aluminum nitride, copper, and silver are arranged sequentially). This arrangement promotes heat transfer from the center of the conductor 1 outward, reducing reverse heat transfer.

[0069] Other aspects are the same as those of Example 4.

[0070] The above description of the present invention is illustrative in combination with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as such non-substantial improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A halogen-free, low-smoke, flame-retardant, single-core, fire-resistant medium-voltage cable comprising an insulated shielded core, characterized in that: The insulated shielded wire core comprises a conductor (1), a fire-resistant layer (2), a conductor shielding layer (4), an insulating layer (5), an insulating shielding layer (6), a heat-insulating layer (7) and a metal shielding layer (8) which are sequentially arranged from the inside to the outside; and a fire-blocking layer (9), an inner flame-retardant layer (10), a metal armor layer (11), a fire-blocking layer (12) and an outer sheath (13) are sequentially arranged on the outer side of the insulated shielded wire core from the inside to the outside.

2. The halogen-free, low-smoke, flame-retardant, single-core, fire-resistant medium-voltage cable according to claim 1, characterized in that: A fire-resistant protective layer (3) is provided between the fire-resistant layer (2) and the conductor shielding layer (4).

3. The halogen-free, low-smoke, flame-retardant, single-core, fire-resistant medium-voltage cable according to claim 1, characterized in that: The conductor (1) is formed by twisting aluminum alloy monofilaments or copper monofilaments in a regular manner, and the diameter of the aluminum alloy monofilaments or copper monofilaments is 2.53-2.54 mm; the fire-resistant layer (2) is formed by wrapping a double layer of synthetic mica tape, and the wrapping coverage rate is 20%-25%.

4. The halogen-free, low-smoke, flame-retardant, single-core, fire-resistant medium-voltage cable according to claim 2, characterized in that: The fire-resistant protective layer (3) is formed by wrapping a single layer of overlapping mesh glass fiber tape, with an overlap rate of 15%-20%.

5. The halogen-free, low-smoke, flame-retardant, single-core, fire-resistant medium-voltage cable according to claim 1, characterized in that: The thermal insulation layer (7) is formed by wrapping a single layer of overlapping mesh glass fiber tape, with an overlap rate of 15%-20%.

6. The halogen-free, low-smoke, flame-retardant, single-core, fire-resistant medium-voltage cable according to claim 1, characterized in that: The fire barrier layer (9) is formed by wrapping double-layer overlapping alkali-free glass fiber tapes, with a wrapping coverage rate of 15%-20%.

7. The halogen-free, low-smoke, flame-retardant, single-core, fire-resistant medium-voltage cable according to claim 1, characterized in that: The inner flame retardant layer (10) is made of a PTFE sheath material with high fire resistance.

8. The halogen-free, low-smoke, flame-retardant, single-core, fire-resistant medium-voltage cable according to claim 1, characterized in that: The fire barrier layer (12) is formed by wrapping a double layer of overlapping synthetic mica tape, with a wrapping overlap rate of 15%-20%; the outer protective layer (13) is made of a low-smoke halogen-free flame-retardant polyolefin sheath material with an oxygen index of 35%.

9. A halogen-free, low-smoke, flame-retardant, single-core, fire-resistant medium-voltage cable according to any one of claims 1 to 8, characterized in that: The conductor (1) comprises a split conductor, and the conductor (1) comprises a plurality of conductor stock blocks (101) arranged in a circumferential direction, wherein each two adjacent conductor stock blocks (101) are separated by an insulating component, and the insulating component comprises two insulating layers (103) respectively contacting the two adjacent conductor stock blocks (101) and a heat conducting layer (102) located between the two insulating layers (103).

10. The halogen-free, low-smoke, flame-retardant, single-core, fire-resistant medium-voltage cable according to claim 9, characterized in that: The heat-conducting layer (102) comprises at least two parts arranged in sequence along a direction extending outward from the center of the conductor (1), and the heat-conducting properties of the materials thereof increase in sequence in the aforementioned order.

Images