Energy-saving emission-reducing modified polypropylene insulating environment-friendly medium-voltage power cable

Abstract

The invention discloses an energy-saving emission-reducing modified polypropylene insulating environment-friendly medium-voltage power cable, which comprises a conductor, and a conductor shielding layer, an insulating layer, an insulating shielding layer, a metal shielding layer, a belting layer and a sheath layer which are sequentially arranged on the conductor from inside to outside, wherein the conductor adopts a second type of round compact structure soft copper conductor specified by GB / T3956-2008, and the sectional area of the conductor is 35-400mm < 2 >; and the insulating layer is formed by extruding a beta crystal form modified polypropylene composite material, and the extruding thickness of the insulating layer is 4.5-10.5 mm. According to the power cable, the modified polypropylene is adopted as the insulating layer, the conductor shielding layer, the insulation shielding layer, the metal shielding layer, the belting layer and the sheath layer are matched, energy consumption reduction in the power transmission process and pollution emission reduction in the whole life cycle are achieved by optimizing the cable structure, and the power cable has the advantages of being simple in overall structure, stable in performance and reasonable in design.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, specifically to an energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable. Background Technology

[0002] Power cables are cable products used to transmit and distribute high-power electrical energy in the main lines of power systems. Medium-voltage power cables serve as the "blood vessels" of the power system. For applications in 10-35kV medium-voltage distribution networks, especially suitable for urban power grid upgrades, new energy grid-connected power plants, and industrial parks, there are not only extremely high requirements for energy consumption control and environmental performance, but also a very large demand for medium-voltage power cables.

[0003] Currently, cross-linked polyethylene (XLPE) is commonly used as the insulation material for medium-voltage power cables (typically referring to voltage levels from 6kV to 35kV). While XLPE possesses excellent electrical properties and meets basic insulation requirements, it has significant shortcomings in terms of energy conservation and emission reduction. First, it has poor environmental performance: XLPE production requires the addition of peroxide crosslinking agents, which produce harmful volatile substances during high-temperature crosslinking. Furthermore, waste cables are difficult to degrade during recycling, and incineration or landfilling can easily cause environmental pollution, which does not meet environmental protection policy requirements. Secondly, there are limitations in temperature resistance: the upper limit of the long-term working temperature of XLPE is 90℃. When the cable is overloaded or in a high-temperature environment, the insulation layer is prone to aging and cracking, which leads to a decrease in insulation performance and a shortening of the cable's service life. Third, the processing is complex: XLPE requires a high-temperature cross-linking process, which has a long production cycle, high energy consumption, and difficulty in controlling the uniformity of cross-linking, which can easily lead to local insulation defects and increase the risk of cable breakdown.

[0004] Polypropylene (PP), as a thermoplastic, theoretically possesses advantages such as recyclability and low production energy consumption. Although some studies have explored using PP to replace XLPE to reduce energy consumption, pure PP material suffers from problems such as high dielectric loss, poor weather resistance, embrittlement at low temperatures, poor resistance to environmental stress cracking, large shrinkage, and insufficient corona resistance. Consequently, its direct application in cable insulation fails to meet the requirements for mechanical properties and long-term operational reliability.

[0005] Therefore, in order to meet the usage requirements of medium-voltage power cables, it is necessary to modify polypropylene and design a matching cable structure to fully leverage its environmental advantages while ensuring the overall performance of the cable. This makes it essential to provide an energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the problems existing in the background art. In order to overcome the defects of high energy consumption in the production of existing medium-voltage power cables, large transmission loss, and high recycling costs, the present invention provides a medium-voltage power cable with a simple structure and convenient use to meet the usage requirements of medium-voltage power cables. Specifically, it is an energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: an energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable, comprising a conductor, and a conductor shielding layer, an insulation layer, an insulation shielding layer, a metal shielding layer, a wrapping layer, and a sheath layer sequentially disposed on the conductor from the inside out; wherein, the conductor adopts a Class 2 circular compacted soft copper conductor as specified in GB / T3956-2008, with a cross-sectional area of ​​35-400 mm². 2 The insulating layer is made of β-crystal modified polypropylene composite material and extruded, with an extrusion thickness of 4.5 to 10.5 mm.

[0008] Furthermore, the energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable of the present invention is adopted, wherein the insulation layer is made of β-crystal modified polypropylene composite material through mixing, twin-screw extrusion granulation, and finally extrusion through an extrusion equipment; the β-crystal modified polypropylene composite material comprises the following raw material composition in parts by weight: 70-90 parts of homopolymer polypropylene, 5-15 parts of elastomer toughening agent, 0.1-1.0 parts of β-crystal nucleating agent and 0.3-1.0 parts of antioxidant.

[0009] Furthermore, the energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable of the present invention is adopted, wherein the β-crystal modified polypropylene composite material comprises the following raw material components by weight: 80-90 parts of homopolymer polypropylene, 8-12 parts of elastomer toughening agent, 0.3-0.7 parts of β-crystal nucleating agent and 0.3-0.6 parts of antioxidant.

[0010] Furthermore, the energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable of the present invention comprises the following raw material composition in parts by weight: 85 parts homopolymer polypropylene, 10 parts elastomer toughening agent, 0.5 parts β-crystal nucleating agent, and 0.5 parts antioxidant.

[0011] Furthermore, in the energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable of the present invention, the elastomer toughening agent is one or a mixture of two of ethylene-octene copolymer and styrene-ethylene-butadiene-styrene block copolymer.

[0012] Furthermore, in the energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable of the present invention, the β-crystal nucleating agent is a rare earth nucleating agent or an amide nucleating agent.

[0013] Furthermore, in the energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable of the present invention, both the conductor shielding layer and the insulation shielding layer are extruded semi-conductive shielding layers, which are obtained by extrusion of semi-conductive polyethylene or semi-conductive polyolefin elastomer materials, wherein the extrusion thickness of both the conductor shielding layer and the insulation shielding layer is 0.5 to 1.5 mm.

[0014] Furthermore, in the energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable of the present invention, the metal shielding layer is a shielding layer formed by overlapping and wrapping copper strips or aluminum alloy strips, and its wrapping thickness is 0.1 to 0.3 mm.

[0015] Furthermore, in the energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable of the present invention, the wrapping layer is made of overlapping glass fiber tape with a thickness of 0.2mm.

[0016] Furthermore, the energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable of the present invention is used, wherein the sheath layer is made of halogen-free, low-smoke, flame-retardant polyolefin material, and its extrusion thickness is 2.0-3.0 mm.

[0017] The energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable of this invention has the following advantages compared with the prior art: by modifying polypropylene, the cable structure design is optimized, achieving energy saving and emission reduction in all stages of cable production, operation, and recycling, while ensuring insulation reliability and mechanical properties, and realizing energy consumption reduction in the power transmission process and pollution reduction throughout the entire life cycle. Specifically, this is reflected in the following aspects: First, it achieves the goal of energy conservation and emission reduction: the insulation layer uses thermoplastic modified polypropylene material, which does not require the traditional high-energy-consuming crosslinking process. Energy savings of 30-50% can be achieved during the production process, and there is no pollution from crosslinking by-products, truly realizing low-carbon and environmentally friendly production.

[0018] Secondly, it achieves environmental friendliness and recyclability: After the cable is scrapped, the insulation layer and most of the structural materials (sheath, etc.) are thermoplastic plastics, which can be 100% recycled through melting and granulation, completely solving the problem of traditional cross-linked cables being difficult to recycle, and meeting the requirements of the circular economy.

[0019] Third, the product has excellent performance: not only is its electrical performance reliable, but the β-crystal modification improves the crystallinity and uniformity of polypropylene, giving it high volume resistivity and high breakdown field strength, fully meeting the requirements for medium-voltage insulation; it also has outstanding heat resistance, with the long-term allowable operating temperature of modified polypropylene insulation reaching 105-120℃, higher than the operating temperature of traditional XLPE (90℃) materials, and its current carrying capacity and overload capacity are stronger; in addition, its mechanical properties are greatly improved, through elastomer toughening and β-crystal nucleation modification, the low-temperature brittleness and easy cracking of ordinary polypropylene are effectively overcome, and its flexibility and impact resistance are significantly improved, making it easier to lay and install.

[0020] Fourth, it is highly safe: equipped with a halogen-free, low-smoke, flame-retardant sheath, it does not release toxic and corrosive halogen acid gases in the event of a fire, and has a low smoke output, which can improve the safety of personnel evacuation and fire rescue.

[0021] In summary, the power cable described in this invention uses modified polypropylene as the insulation layer, and is combined with a conductor shielding layer, an insulating shielding layer, a metal shielding layer, a wrapping tape layer, and a sheathing layer. By optimizing the cable structure, it achieves energy consumption reduction during power transmission and pollution reduction throughout the entire life cycle. It has a simple overall structure, stable performance, and reasonable design, and is worthy of widespread use. Attached Figure Description

[0022] The present invention will now be described in further detail with reference to the accompanying drawings.

[0023] Figure 1 This is a schematic diagram of the structure of the present invention.

[0024] As shown in the figure: 1-Conductor, 2-Conductor shielding layer, 3-Insulation layer, 4-Insulation shielding layer, 5-Metallic shielding layer, 6-Wrapping layer, 7-Sheath layer. Detailed Implementation

[0025] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0026] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness or purpose of the invention, should still fall within the scope of the disclosed technical content. Furthermore, the terms "upper," "lower," "left," and "right" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection" and "provided with" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] It should be noted that the term "comprising" or any other variation is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0029] like Figure 1 As shown, this invention provides an energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable, comprising a conductor 1, and, from the inside out, a conductor shielding layer 2, an insulation layer 3, an insulation shielding layer 4, a metal shielding layer 5, a wrapping tape layer 6, and a sheath layer 7, sequentially disposed on the conductor 1; wherein, the conductor 1 adopts a Class 2 circular compacted soft copper conductor as specified in GB / T3956-2008, with a cross-sectional area of ​​35-400 mm². 2 The insulation layer 3 is made of β-crystal modified polypropylene composite material and extruded, with an extrusion thickness of 4.5 to 10.5 mm, which corresponds to the rated voltage of the cable from 6 kV to 35 kV.

[0030] Furthermore, in the energy-saving and emission-reducing modified polypropylene insulated environmentally friendly medium-voltage power cable provided by this invention, both the conductor shielding layer 2 and the insulation shielding layer 4 are extruded semi-conductive shielding layers, obtained by extrusion of semi-conductive polyethylene or semi-conductive polyolefin elastomer material, wherein the extrusion thickness of both the conductor shielding layer 2 and the insulation shielding layer 4 is 0.5–1.5 mm. The metal shielding layer 5 is a shielding layer formed by overlapping and wrapping copper or aluminum alloy strips, with a wrapping thickness of 0.1–0.3 mm. The wrapping layer 6 is formed by overlapping and wrapping 0.2 mm thick fiberglass tape. The sheath layer 7 is made of halogen-free, low-smoke, flame-retardant polyolefin material, with an extrusion thickness of 2.0–3.0 mm. In the specific manufacturing process, the wrapping thickness of the metal shielding layer 5, and the extrusion thickness of the insulation layer 3 and the sheath layer 7, can be determined according to the rated voltage of the cable. Example

[0031] This embodiment provides a 26 / 35kV power cable. To illustrate the advantages of using the power cable described in this embodiment, its manufacturing process meets the goals of energy conservation and emission reduction, and the manufactured cable can meet its usage requirements. The power cable provided in this embodiment includes, from the inside out, a conductor 1, a conductor shielding layer 2, an insulation layer 3, an insulation shielding layer 4, a metallic shielding layer 5, a wrapping layer 6, and a sheath layer 7; wherein, Conductor 1: A Class 2 round, compacted soft copper conductor as specified in GB / T3956-2008, with a cross-sectional area of ​​300 mm². 2 This allows the manufactured power cables to have good conductivity and flexibility.

[0032] Conductor shielding layer 2: It is made of semi-conductive polyethylene material by extrusion, with an extrusion thickness of about 0.8 mm. It is in smooth contact with the surface of conductor 1, so that the electric field can be uniform.

[0033] Insulation layer 3: This layer is extruded from β-crystalline modified polypropylene composite material, with an extrusion thickness of 10.2 mm (corresponding to a 26 / 35kV voltage rating). This polypropylene composite material is composed of 85 parts by weight of homopolymer polypropylene (PPH-T022), 10 parts by weight of POE elastomer (Engage 8150), 0.5 parts by weight of amide-based β-crystal nucleating agent (TMB-5), and 0.5 parts by weight of antioxidant (1010), mixed at high speed and granulated by twin-screw extrusion. This insulation layer is directly water-cooled and shaped after extrusion, eliminating the need for a crosslinking process. This reduces the significant heat energy consumed in the crosslinking process.

[0034] Insulating shielding layer 4: It is made of semi-conductive polyethylene material by extrusion, with an extrusion thickness of about 0.8 mm, forming a smooth interface with the outer surface of the insulating layer.

[0035] Metal shielding layer 5: It is made of overlapping soft copper strips with a thickness of 0.12mm, serving as a channel for current protection and electromagnetic shielding.

[0036] Layer 6: It is made of overlapping and wrapping fiberglass tape with a thickness of 0.2mm.

[0037] Sheath layer 7: Made of halogen-free, low-smoke, flame-retardant polyolefin material by extrusion, with an extrusion thickness of approximately 2.5 mm, thus providing mechanical protection and flame-retardant fireproof functions.

[0038] Because insulation layer 3 is extruded from β-crystal modified polypropylene composite material, which is composed of homopolymer polypropylene (PPH-T022), POE elastomer (Engage 8150), amide β-crystal nucleating agent (TMB-5), and antioxidant (1010), it is produced by high-speed mixing and twin-screw extrusion granulation, and finally extruded according to existing methods. β-crystal modification improves the crystallinity and uniformity of polypropylene, giving it high volume resistivity and high breakdown field strength, fully meeting the requirements of medium-voltage insulation. At the same time, it also has excellent heat resistance. The long-term allowable operating temperature of modified polypropylene insulation can reach 105-120℃, which is higher than the operating temperature of traditional XLPE (90℃) material, and its current carrying capacity and overload capacity are stronger. In addition, its mechanical properties can be greatly improved: through elastomer toughening and β-crystal nucleation modification, the low-temperature brittleness and easy cracking of ordinary polypropylene are effectively overcome, and the flexibility and impact resistance are significantly improved, making it easier to lay and install.

[0039] The cable production process is as follows: conductor drawing → conductor shielding layer extrusion → modified polypropylene insulation layer extrusion (and cooling) → insulation shielding layer extrusion → metal shielding layer wrapping → tape wrapping → sheathing. Existing cable manufacturing methods can be used for the specific preparation, thus eliminating the need for cross-linking pipes, resulting in faster production line speeds and significantly reduced energy consumption.

[0040] In summary, the power cable described in this invention uses modified polypropylene as the insulation layer 3, and is combined with a conductor shielding layer 2, an insulating shielding layer 4, a metal shielding layer 5, a wrapping layer 6, and a sheath layer 7. By optimizing the cable structure, it achieves energy consumption reduction during power transmission and pollution reduction throughout the entire life cycle. It has a simple overall structure, stable performance, and reasonable design, and is worthy of widespread use.

[0041] Other aspects of this invention that are not detailed herein are all conventional techniques known to those skilled in the art.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations can be made by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made using the present invention should be included within the protection scope of the present invention.

Claims

1. An energy saving and emission reduction modified polypropylene insulation environment-friendly medium voltage power cable, characterized in that: The utility model relates to a kind of cable, including conductor (1), and conductor shielding layer (2), insulating layer (3), insulating shielding layer (4), metal shielding layer (5), tape layer (6) and sheath layer (7) sequentially arranged on conductor (1) from inside to outside;Wherein, the conductor (1) adopts the soft copper conductor of the second type circular tight-press structure specified in GB / T3956-2008, and the cross-sectional area is 35~400mm 2 ;And the insulating layer (3) is made of the extrusion of β crystal modification polypropylene composite material, and the extrusion thickness is 4.5~10.5mm.

2. An energy saving and emission reduction modified polypropylene insulation environment-friendly medium voltage power cable according to claim 1, characterized in that: The insulating layer (3) is made of a beta crystal modified polypropylene composite material, which is mixed, extruded by a double screw, granulated, and finally extruded by an extrusion coating device; the beta crystal modified polypropylene composite material comprises the following raw material components by weight: 70-90 parts of homopolymer polypropylene, 5-15 parts of an elastomer toughening agent, 0.1-1.0 parts of a beta crystal nucleating agent, and 0.3-1.0 parts of an antioxidant.

3. An energy saving and emission reduction modified polypropylene insulation environment-friendly medium voltage power cable according to claim 2, characterized in that: The beta crystal modified polypropylene composite material comprises the following raw material components by weight: 80-90 parts of homopolymer polypropylene, 8-12 parts of an elastomer toughening agent, 0.3-0.7 parts of a beta crystal nucleating agent, and 0.3-0.6 parts of an antioxidant.

4. The energy-saving and emission-reducing modified polypropylene insulation environment-friendly medium-voltage power cable according to claim 3, characterized in that: The beta crystal modified polypropylene composite material comprises the following raw material components by weight: 85 parts of homopolymer polypropylene, 10 parts of an elastomer toughening agent, 0.5 parts of a beta crystal nucleating agent, and 0.5 parts of an antioxidant.

5. The energy saving and emission reduction modified polypropylene insulation environment-friendly medium voltage power cable according to claim 4, characterized in that: The elastomer toughening agent is a mixture of one or both of ethylene-octene copolymer and styrene-ethylene-butadiene-styrene block copolymer.

6. An energy saving and emission reduction modified polypropylene insulation environment-friendly medium voltage power cable according to claim 4, characterized in that: The beta crystal nucleating agent is a rare earth nucleating agent or an amide nucleating agent.

7. The energy saving and emission reduction modified polypropylene insulation environment-friendly medium voltage power cable according to claim 1, characterized in that: The conductor shielding layer (2) and the insulating shielding layer (4) are both extruded semi-conductive shielding layers, which are extruded by semi-conductive polyethylene or semi-conductive polyolefin elastomer material, and the extrusion thickness of the conductor shielding layer (2) and the insulating shielding layer (4) is 0.5-1.5 mm.

8. An energy saving and emission reduction modified polypropylene insulation environment-friendly medium voltage power cable according to claim 1, characterized in that: The metal shielding layer (5) is a shielding layer formed by overlapping and wrapping a copper strip or an aluminum alloy strip, and the wrapping thickness is 0.1-0.3 mm.

9. The energy saving and emission reduction modified polypropylene insulation environment-friendly medium voltage power cable according to claim 1, characterized in that: The wrapping tape layer (6) is made of glass fiber tape with a thickness of 0.2 mm, which is overlapped and wrapped.

10. The energy saving and emission reduction modified polypropylene insulation environment-friendly medium voltage power cable according to claim 1, characterized in that: The sheath layer (7) is made of halogen-free low-smoke flame-retardant polyolefin material, and the extrusion thickness is 2.0-3.0 mm.

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