Polypropylene insulating fireproof flame-retardant environment-friendly medium-voltage power cable

Abstract

The utility model discloses a polypropylene insulating fireproof flame-retardant environment-friendly medium-voltage power cable, which comprises an insulating wire core and an insulating layer, and is characterized in that the insulating layer is wound on the outer side of the insulating wire core; the insulating layer comprises a semi-conductive nylon tape wrapping layer, a metal shielding layer, a glass fiber tape wrapping layer, a heat insulation layer, a fireproof tape wrapping layer, an oxygen isolation layer, a first flame-retardant tape wrapping layer, a fireproof layer, an armor layer, a second flame-retardant tape wrapping layer and an outer sheath layer from inside to outside in sequence. According to the utility model, through the double-structure design of the double fireproof layers, the heat insulation layer and the oxygen isolation layer, the fireproof performance and the flame-retardant B1-level combustion performance of the aluminum alloy core medium-voltage cable are realized, the bunched A-type combustion performance is satisfied, and the high-performance development trend of the cable is met; and the conductor material and the metal shielding material are made of aluminum alloy materials, so that the influence of overhigh price of the copper rod on the cost of the cable is reduced, and the comprehensive competitiveness of the cable market is enhanced.

Description

Technical Field

[0001] This utility model belongs to the technical field of medium-voltage fire-resistant cables, specifically relating to a polypropylene insulated fire-resistant, flame-retardant, and environmentally friendly medium-voltage power cable. Background Technology

[0002] The statements herein provide only background information related to this invention and do not necessarily constitute prior art.

[0003] Currently, cross-linked polyethylene (XLPE) is widely used as the insulation material for medium-voltage cables in the power industry. During the production of XLPE cables, the decomposition of the cross-linking agent dicumyl peroxide produces a large number of polar low-molecular-weight byproducts that remain in the insulation, increasing the dielectric constant of the insulation and affecting the performance and service life of the cable. On the other hand, polyethylene (PE) material becomes a thermosetting material after cross-linking, which is difficult to recycle and can only be disposed of by incineration, landfill, and other methods, resulting in resource waste and environmental pollution. With the continuous improvement of society's requirements for low-carbon, environmentally friendly, energy-saving and emission-reduction, energy conservation and environmental protection in the cable industry have become the future development direction.

[0004] With the continuous improvement of cable standards, the requirements for high-performance cables are becoming increasingly stringent. Therefore, designing a cable product that meets the basic electrical performance requirements, as well as the fire resistance and bundled combustion performance requirements, while also closely approximating indicators such as low heat release, smoke generation characteristics, and low toxicity during a fire, and ensuring the safety of people and property during normal building use and fire incidents, has become a key focus of product development.

[0005] With dwindling copper resources and soaring copper prices, cable costs have risen sharply. Aluminum alloy conductors, with their excellent electrical conductivity, thermal conductivity, and corrosion resistance, have become a popular cost-saving measure for most cable companies, replacing copper conductors with high-conductivity aluminum alloy conductors. However, aluminum alloy conductors have a melting point of 650℃, while fire-resistant cables are typically tested at temperatures between 950℃ and 1000℃, and actual fire temperatures can reach around 1000℃. Therefore, in high-temperature environments, if the required fire resistance and insulation performance cannot be met, the aluminum conductor can easily melt, causing the cable to lose its conductivity. Thus, the fire-resistant structural design of cables is crucial. Utility Model Content

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a polypropylene insulated fire-resistant, flame-retardant, and environmentally friendly medium-voltage power cable. Through a dual-structure design of double fire-resistant layer, heat insulation layer, and oxygen barrier layer, it achieves fire resistance and flame-retardant B1-level combustion performance of aluminum alloy core medium-voltage cable, while also meeting the Class A combustion performance requirements for bundled cables, which is in line with the trend of high-performance cable development. The conductor material and metal shielding material are made of aluminum alloy, which reduces the impact of excessively high copper rod prices on cable costs and enhances the overall competitiveness of the cable market.

[0007] To achieve the above objectives, this utility model is implemented through the following technical solution:

[0008] The present invention provides a polypropylene insulated fire-resistant and flame-retardant environmentally friendly medium-voltage power cable, comprising: an insulated core and an insulation layer, wherein the insulation layer is wrapped around the outside of the insulated core; the insulation layer, from the inside to the outside, consists of a semi-conductive nylon tape wrapping layer, a metal shielding layer, a fiberglass tape wrapping layer, a heat insulation layer, a fire-resistant tape wrapping layer, an oxygen barrier layer, a first flame-retardant tape wrapping layer, a fireproof layer, an armor layer, a second flame-retardant tape wrapping layer, and an outer sheath layer.

[0009] In at least one embodiment, the center of the insulated core is a cable conductor, and the outside of the cable conductor is sequentially wrapped with a semi-conductive conductor shielding layer, a polypropylene insulation layer, and a semi-conductive insulation shielding layer; the number of the insulated cores is 1 or 3.

[0010] In at least one embodiment, the cable conductor is a type 2 compacted round aluminum alloy conductor.

[0011] In at least one embodiment, the semiconductive conductor shielding layer, the polypropylene insulation layer, and the semiconductive insulation shielding layer are extruded together by three-layer co-extrusion, and the insulation eccentricity is less than 8%.

[0012] In at least one embodiment, the metal shielding layer is specifically an aluminum alloy wire shielding and an aluminum alloy strip loosely wound structure.

[0013] In at least one embodiment, the fiberglass tape wrapping layer is an alkali-free fiberglass tape overlapping wrapping structure.

[0014] In at least one embodiment, the heat insulation layer is made of a high flame-retardant polyolefin sheath material with an oxygen index ≥45%; the oxygen barrier layer is made of a high flame-retardant polyolefin sheath material with an oxygen index ≥45%.

[0015] In at least one embodiment, the first flame-retardant wrapping layer is specifically a low-smoke halogen-free flame-retardant wrapping layer; the second flame-retardant wrapping layer is specifically a low-smoke halogen-free flame-retardant wrapping layer; and the outer sheath layer is made of B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material.

[0016] In at least one embodiment, the fire-resistant tape wrapping layer is an overlapping wrapping structure of ceramicized silicone rubber composite tape; the fireproof layer is specifically a ceramicized polyolefin fireproof layer.

[0017] In at least one embodiment, the armor layer is specifically a metal strip armor layer.

[0018] The beneficial effects of the above-described technical solution of this utility model are as follows:

[0019] 1) The polypropylene insulated fire-resistant, flame-retardant and environmentally friendly medium-voltage power cable of this utility model achieves fire resistance and flame-retardant B1-level combustion performance of aluminum alloy core medium-voltage cable through a dual-structure design of double fire-resistant layer, heat insulation layer and oxygen barrier layer, while meeting the Class A combustion performance of bundled cables, which is in line with the development trend of high-performance cables.

[0020] 2) The conductor material and metal shielding material of the polypropylene insulated fire-resistant and flame-retardant environmentally friendly medium-voltage power cable of this utility model are made of aluminum alloy, which reduces the impact of the high price of copper rod on the cable cost and enhances the overall competitiveness of the cable market.

[0021] 3) The insulating material of the polypropylene insulated fire-resistant and flame-retardant environmentally friendly medium-voltage power cable of this utility model is polypropylene insulating material. Compared with traditional cross-linked polyethylene material, polypropylene does not require cross-linking and does not introduce cross-linking byproducts. It can be recycled through melting or degradation, has low production energy consumption, and is environmentally friendly and economical. Attached Figure Description

[0022] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0023] Figure 1 This is a schematic diagram of the internal cross-section of a polypropylene insulated fire-resistant, flame-retardant, and environmentally friendly medium-voltage power cable according to this utility model.

[0024] In the diagram: 1. Cable conductor; 2. Semi-conductive conductor shielding layer; 3. Polypropylene insulation layer; 4. Semi-conductive insulation shielding layer; 5. Semi-conductive nylon tape wrapping layer; 6. Metal shielding layer; 7. Fiberglass tape wrapping layer; 8. Heat insulation layer; 9. Fire-resistant tape wrapping layer; 10. Oxygen barrier layer; 11. First flame-retardant tape wrapping layer; 12. Fireproof layer; 13. Armoring layer; 14. Second flame-retardant tape wrapping layer; 15. Outer sheath layer.

[0025] The distances or dimensions between parts have been exaggerated to show their positions; the diagram is for illustrative purposes only. Detailed Implementation

[0026] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0027] As described in the background section, the purpose of this utility model is to overcome the shortcomings of the existing technology and provide a polypropylene insulated fire-resistant, flame-retardant, and environmentally friendly medium-voltage power cable. Through a dual-structure design of double fire-resistant layers, heat insulation layers, and oxygen-barrier layers, it achieves fire resistance and flame-retardant B1-level combustion performance of the aluminum alloy core medium-voltage cable, while also meeting the Class A combustion performance requirements for bundled cables, which aligns with the trend of high-performance cable development. The use of aluminum alloy for both the conductor and metal shielding materials reduces the impact of excessively high copper rod prices on cable costs and enhances the overall competitiveness of the cable in the market.

[0028] Example 1

[0029] In a typical embodiment of this utility model, such as Figure 1 As shown in the figure, this embodiment discloses a polypropylene insulated fire-resistant, flame-retardant, and environmentally friendly medium-voltage power cable, comprising: an insulated core and an insulation layer, the insulation layer being wrapped around the outside of the insulated core; the insulation layer, from the inside out, consists of a semi-conductive nylon tape wrapping layer 5, a metal shielding layer 6, a fiberglass tape wrapping layer 7, a heat insulation layer 8, a fire-resistant tape wrapping layer 9, an oxygen barrier layer 10, a first flame-retardant tape wrapping layer 11, a fireproof layer 12, an armor layer 13, a second flame-retardant tape wrapping layer 14, and an outer sheath layer 15. Through the double-layer structure design of the insulation layer (fire-resistant tape wrapping layer 9 and fireproof layer 12), heat insulation layer, and oxygen barrier layer, the medium-voltage power cable proposed in this embodiment achieves fire resistance and flame-retardant B1-level combustion performance, while also meeting the bundled Class A combustion performance requirements, conforming to the green, environmentally friendly, and low-carbon development trend of the cable industry.

[0030] In this embodiment, the center of the insulated core is the cable conductor 1, and the cable conductor 1 is sequentially wrapped with a semi-conductive conductor shielding layer 2, a polypropylene insulation layer 3, and a semi-conductive insulation shielding layer 4. The number of insulated cores is 1 or 3, and the power transmission requirements of the medium-voltage cable can be met by adjusting the number of insulated cores.

[0031] Furthermore, cable conductor 1 is a Class 2 compacted round aluminum alloy conductor used for power transmission in the cable. It is made by straightening 8030 series aluminum alloy rods and then regularly stranding them into a Class 2 compacted round aluminum alloy conductor. After stranding, it is compacted using a compaction die with a compaction coefficient of not less than 0.90. The maximum DC resistance of the conductor at 20℃ meets the requirements of GB / T 3956-2008. Simultaneously, the semi-conductive conductor shielding layer 2, polypropylene insulation layer 3, and semi-conductive insulation shielding layer 4 are extruded together using a three-layer co-extrusion process, with the insulation eccentricity controlled within less than 8%, ensuring the electrical and mechanical properties of the insulated core. Optionally, the semi-conductive conductor shielding layer 2 can be a peelable semi-conductive shielding material, the insulation layer can be polypropylene insulation material, and the semi-conductive insulation shielding layer 4 can be a peelable semi-conductive shielding material, with the insulation unit being extruded together using a three-layer co-extrusion process.

[0032] In this embodiment, a semi-conductive nylon tape wrapping layer 5 is provided on the innermost layer of the insulation layer, that is, on the outside of the insulated wire core. This structure allows the semi-conductive insulating shielding layer 4 and the metal shielding layer 6 to be at the same potential potential, thus avoiding the generation of a potential difference that could lead to charge discharge.

[0033] The outer side of the semi-conductive nylon tape wrapping layer 5 is a metal shielding layer 6 and a fiberglass tape wrapping layer 7. Specifically, the metal shielding layer 6 is formed by aluminum alloy wire shielding and a loosely wound aluminum alloy tape structure, wrapping the entire insulated core to meet the shielding performance requirements of the insulated core and bear the short-circuit current during faults. The fiberglass tape wrapping layer 7 is made of two layers of alkali-free fiberglass tape overlapping and wrapping. The heat generated by the cable can be dissipated through the gaps between the glass fibers, thereby reducing the heat of the cable core and protecting the internal structure of the cable.

[0034] A heat insulation layer 8 is provided on the outside of the fiberglass tape wrapping layer 7. The heat insulation layer 8 is made of high flame-retardant polyolefin sheath material (oxygen index ≥45%) to reduce the conduction of external heat to the insulated core under fire conditions, so that the insulation maintains its electrical performance throughout the test and does not undergo thermal deformation during the test, thus preventing breakdown.

[0035] The outer side of the insulation layer 8 is set as a fire-resistant tape wrapping layer 9, which is composed of four layers of 0.4mm ceramicized silicone rubber composite tape wrapped together, which can directly resist flames. In the event of a fire, the ceramicized silicone rubber composite tape will be burned into a hard inorganic material, forming a hard protective layer. This protective layer is a loose and porous crust material, which can withstand high temperatures of 950℃~1300℃, effectively preventing heat transfer and playing a role in oxygen isolation and heat insulation, providing good protection for the insulated wire core.

[0036] An oxygen barrier layer 10 is provided on the outside of the fire-resistant tape wrapping layer 9. This layer is made of a high flame-retardant polyolefin sheath material (oxygen index ≥45%). This material releases no halogen acid gas during combustion, and the release of toxic and corrosive gases is extremely low, resulting in low smoke concentration. It meets technical specifications such as low smoke, halogen-free, low toxicity, and high light transmittance. Furthermore, this material has the characteristic of forming a shell that is not easily detached when exposed to fire, effectively isolating flames and heat and maintaining the stability of the cable structure.

[0037] The outer side of the oxygen barrier layer 10 is provided with a first flame-retardant wrapping layer 11, which is made of low-smoke halogen-free flame-retardant wrapping tape, which has the function of reducing heat transfer to the cable core and further protecting the insulated core.

[0038] The outer side of the first flame-retardant strip wrapping layer 11 is set as a fireproof layer 12, specifically a ceramicized polyolefin fireproof layer 12. In the event of a fire, the ceramicized polyolefin fireproof layer 12 forms a hard armor shell after ablation, and the residue is pure ceramic inorganic material. The ceramic-like armor can form uniform honeycomb-shaped foam pores during the ablation process. The ceramicized shell after burning can withstand high temperatures up to 1500℃, and can play a very good role in oxygen isolation, heat insulation and fire resistance. At the same time, it is resistant to spraying, and after burning, it produces less smoke, is non-toxic and odorless, and will not cause secondary harm to the human body.

[0039] The outer side of the fireproof layer 12 is set as an armor layer 13, which adopts a metal strip armor layer and has functions such as mechanical protection, bearing radial tensile force and magnetic field shielding.

[0040] The outer side of the armor layer 13 is set as a second flame-retardant wrapping layer 14, which also adopts a low-smoke halogen-free flame-retardant wrapping tape, which has the function of reducing heat transfer to the cable core and further protecting the insulated core.

[0041] The outermost layer of the second flame-retardant wrapping layer 14 is set as the outer sheath layer 15, which is made of B1 grade low smoke halogen-free flame-retardant polyolefin sheath material. When this material burns, its heat release and combustion rate meet the requirements of flame retardant B1 grade, which is in line with the green, environmentally friendly and low-carbon development trend of the cable industry.

[0042] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A polypropylene insulated fire resistant flame retardant environment friendly medium voltage power cable characterized in that, include: The insulating core and the insulating layer are wrapped around the outside of the insulating core. The insulating layer consists of, from the inside to the outside, a semi-conductive nylon tape wrapping layer, a metal shielding layer, a fiberglass tape wrapping layer, a heat insulation layer, a fire-resistant tape wrapping layer, an oxygen barrier layer, a first flame-retardant tape wrapping layer, a fireproof layer, an armor layer, a second flame-retardant tape wrapping layer, and an outer sheath layer.

2. A polypropylene insulated fire resistant flame retardant environment friendly medium voltage power cable as claimed in claim 1, wherein, The center of the insulated wire core is the cable conductor, and the outside of the cable conductor is successively wrapped with a semi-conductive conductor shielding layer, a polypropylene insulation layer, and a semi-conductive insulation shielding layer; the number of the insulated wire cores is 1 or 3.

3. A polypropylene insulated fire resistant flame retardant environment friendly medium voltage power cable as claimed in claim 2, wherein, The cable conductor is a type 2 compacted round aluminum alloy conductor.

4. A polypropylene insulated fire resistant flame retardant environment friendly medium voltage power cable as claimed in claim 2, wherein, The semiconductive conductor shielding layer, polypropylene insulation layer, and semiconductive insulation shielding layer are extruded together through a three-layer co-extrusion process, with an insulation eccentricity of less than 8%.

5. A polypropylene insulated fire resistant flame retardant environment friendly medium voltage power cable as claimed in claim 1, wherein, The metal shielding layer is specifically an aluminum alloy wire shielding and an aluminum alloy strip loosely wound structure.

6. A polypropylene insulated fire resistant flame retardant environment friendly medium voltage power cable as claimed in claim 1, wherein, The fiberglass tape wrapping layer is an alkali-free fiberglass tape overlapping wrapping structure.

7. The polypropylene insulated fire-resistant, flame-retardant, and environmentally friendly medium-voltage power cable as described in claim 1, characterized in that, The heat insulation layer is made of high flame-retardant polyolefin sheath material with an oxygen index ≥45%; the oxygen barrier layer is made of high flame-retardant polyolefin sheath material with an oxygen index ≥45%.

8. A polypropylene insulated fire resistant flame retardant environment friendly medium voltage power cable as claimed in claim 1, wherein, The first flame-retardant wrapping layer is specifically a low-smoke halogen-free flame-retardant wrapping layer; the second flame-retardant wrapping layer is specifically a low-smoke halogen-free flame-retardant wrapping layer; the outer sheath layer is made of B1 grade low-smoke halogen-free flame-retardant polyolefin sheath material.

9. A polypropylene insulated fire resistant flame retardant environment friendly medium voltage power cable as claimed in claim 1, wherein, The fire-resistant tape wrapping layer is a ceramicized silicone rubber composite tape overlapping wrapping structure; the fireproof layer is specifically a ceramicized polyolefin fireproof layer.

10. A polypropylene insulated fire resistant flame retardant environment friendly medium voltage power cable as claimed in claim 1, wherein, The armor layer is specifically a metal strip armor layer.

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