A high voltage short degassed xlpe insulated power cable and a method of manufacturing the same

Abstract

The application belongs to the technical field of cross-linked polyethylene cable production, and provides a high-voltage short-degassing XLPE insulated power cable and a manufacturing method thereof, which comprises a cable core, a transition buffer layer and a metal shielding layer arranged from inside to outside; the cable core comprises a conductor and a semi-conductive low-byproduct XLPE conductor shielding layer extruded on the outer surface of the conductor by using three-layer co-extrusion production, a low-byproduct XLPE insulation layer extruded on the outer surface of the semi-conductive low-byproduct XLPE conductor shielding layer by using low-byproduct XLPE insulation material, and a semi-conductive low-byproduct XLPE insulation shielding layer extruded on the outer surface of the low-byproduct XLPE insulation layer by using semi-conductive low-byproduct XLPE shielding material; the metal shielding layer is circumferentially provided with a gas sensing optical fiber.

Description

Technical Field

[0001] The present invention belongs to the technical field of cross-linked polyethylene cable production, and particularly relates to a high-voltage short-degassing XLPE-insulated power cable and a manufacturing method thereof. Background Art

[0002] The statements in this part merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] High-voltage power cables are an important part of the power system's transmission and distribution network. The insulating layer of high-voltage power cables is generally extruded using cross-linked polyethylene (XLPE) as the raw material. However, XLPE needs to be cross-linked during the extrusion production process, and the cross-linking pipeline of high-voltage XLPE cables is long and the cross-linking temperature is high, which requires a certain time and temperature for degassing, resulting in high energy consumption costs for XLPE cable production. By-products during production (such as waste and waste gases like cumyl alcohol, acetophenone, alpha-methylstyrene or methane) pollute the environment.

[0004] Currently, the cross-linking efficiency of high-voltage XLPE cables is relatively low. How to shorten the degassing time of high-voltage XLPE-insulated cables while reducing the concentration of cross-linking by-products has become a research direction in the cable industry. Summary of the Invention

[0005] To solve the above problems, the present invention proposes a high-voltage short-degassing XLPE-insulated power cable and a manufacturing method thereof. A low-by-product XLPE insulating material is used, and a transition buffer layer is provided on the outer layer of the cable core to adsorb the cross-linking by-product methane during cable operation, reducing the concentration of cross-linking by-products; the cable core adopts a three-layer co-extrusion process, and the pipeline for gravity feeding of the insulating material is heated and modified to improve the cross-linking efficiency of high-voltage power cables.

[0006] According to some embodiments, the first aspect of the present invention provides a high-voltage short-degassing XLPE-insulated power cable, adopting the following technical solution:

[0007] A high-voltage short-degassing XLPE-insulated power cable includes a cable core, a transition buffer layer, and a metal shielding layer arranged from the inside out; wherein, the cable core includes a conductor arranged from the inside out, and a semi-conductive low-by-product XLPE conductor shielding layer, a low-by-product XLPE insulating layer, and a semi-conductive low-by-product XLPE insulation shielding layer which are extruded and wrapped on the outer surface of the conductor, the semi-conductive low-by-product XLPE conductor shielding layer, and the low-by-product XLPE insulating layer respectively by using a three-layer co-extrusion production; a gas sensing optical fiber is circumferentially arranged on the metal shielding layer.

[0008] In an alternative implementation, the metal shielding layer includes spaced-apart metal wire shields and a sensing optical fiber unit. The sensing optical fiber unit uses a gas-sensing optical fiber, and the gas-sensing optical fiber is disposed along the length direction of the high-voltage short-degassing XLPE insulated power cable.

[0009] In an alternative implementation, the diameters of the extruder screws used in the three-layer co-extrusion production are 75 mm, 175 mm, and 90 mm respectively, the mesh numbers of the filter screens are 20 / 40 / 80 / 40 / 20, 40 / 80 / 150 / 300 / 150 / 80 / 40 / 20, 20 / 40 / 80 / 40 / 20 respectively, and the partition temperature settings are 80 o C / 100 o C / 110 o C / 110 o C, 115 o C / 118 o C / 115 o )7]]C / 115 o C / 115 o C / 115 o C, 80 o C / 100 o C / 110 o C / 110 o C; in the three-layer co-extrusion production, the pipeline for the gravity feeding of the insulating material is retrofitted by heating with an energized coil.

[0010] In an alternative implementation, the transition buffer layer is wound around the cable core by a wrapping machine.

[0011] In an alternative implementation, the conductor uses a compact round conductor or a stranded block split conductor; both the compact round conductor and the stranded block split conductor are stranded by single wires made of copper, aluminum or aluminum alloy materials.

[0012] In an alternative implementation, the high-voltage short-degassing XLPE insulated power cable further includes a first semiconductive buffer layer disposed between the transition buffer layer and the metal shielding layer, and a second semiconductive buffer layer, a metal sheath, an anticorrosion layer, an outer sheath and an outer electrode disposed in sequence outside the metal shielding layer.

[0013] Furthermore, the metal sheath uses a smooth aluminum sheath or a corrugated aluminum sheath; the thickness of the smooth aluminum sheath is set to 1.8 mm and others, and the thickness of the corrugated aluminum sheath is set to 2.0 mm - 2.3 mm.

[0014] Furthermore, the anticorrosion layer uses a hot-melt adhesive material for bonding the metal sheath and the outer sheath; the outer sheath uses a polyethylene-based material, a polypropylene-based material or a polyvinyl chloride material, and the thickness of the outer sheath is set to 4 mm - 5 mm.

[0015] According to some embodiments, the second solution of the present invention provides a manufacturing method for a high-voltage short degassing XLPE insulated power cable, which is used to manufacture the high-voltage short degassing XLPE insulated power cable provided in the first solution, and adopts the following technical solutions:

[0016] A manufacturing method for a high-voltage short degassing XLPE insulated power cable includes: sequentially arranging a transition buffer layer, a first semiconductive buffer layer, a metal shielding layer, a second semiconductive buffer layer, a metal sheath, an anticorrosion layer, an outer sheath, and an outer electrode on a cable core; absorbing methane gas in the cable crosslinking by-products through the transition buffer layer, and monitoring the operating state of the cable through a gas sensing optical fiber arranged in the metal shielding layer; adopting three-layer coextrusion production in the cable core, and simultaneously reforming the pipeline for gravity feeding of the insulating material by heating treatment with an energized coil.

[0017] In an optional implementation manner, the preparation process of the above cable core is as follows:

[0018] Strand multiple single wires to form a conductor;

[0019] Wind a conductor tape around the conductor;

[0020] Pass through an XLPE three-layer coextrusion suspension production line, and simultaneously extrude a semiconductive low by-product XLPE conductor shielding layer, a low by-product XLPE insulating layer, and a semiconductive low by-product XLPE insulation shielding layer.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The present invention adds a transition buffer layer with the function of absorbing methane gas, which can effectively prevent methane gas in the cable crosslinking by-products from escaping between the metal sheath and the cable core, and adds a gas sensing optical fiber for monitoring the operating stability of the cable between the metal shielding layers; selects raw materials for the semiconductive low by-product XLPE conductor shielding layer, the low by-product XLPE insulating layer, and the semiconductive low by-product XLPE insulation shielding layer, enabling the power cable to innovatively possess the characteristics of environmental protection, directly reducing the concentration of cable crosslinking by-products at the source, and simultaneously adopting a three-layer coextrusion process, and innovatively reforming the pipeline for gravity feeding of the insulating material by heating treatment to effectively improve the crosslinking efficiency of the high-voltage power cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The schematic diagrams in the specification forming a part of this embodiment are used to provide a further understanding of this embodiment. The illustrative embodiments and descriptions thereof are used to explain this embodiment and do not constitute an improper limitation to this embodiment.

[0024] Figure 1 It is a schematic structural diagram of the high-voltage short degassing XLPE insulated power cable in Embodiment 1 of the present invention;

[0025] Figure 2 Schematic diagram of the gravity feeding pipeline heating coil in the first embodiment of the present invention;

[0026] Among them, 1. Conductor; 2. Semi-conductive low by-product XLPE conductor shielding layer; 3. Low by-product XLPE insulation layer; 4. Semi-conductive low by-product XLPE insulation shielding layer; 5. Transition buffer layer; 6. First semi-conductive buffer layer; 7. Metal shielding layer; 8. Second semi-conductive buffer layer; 9. Metal sheath; 10. Anti-corrosion layer; 11. Outer sheath; 12. Outer electrode. Specific embodiments

[0027] The present invention will be further described below in conjunction with the drawings and embodiments.

[0028] It should be noted that the following detailed description is exemplary and intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0029] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments of the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] In the present invention, terms such as "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "side", "bottom", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only relationship terms determined for the convenience of describing the structural relationship of each component or element of the present invention and do not specifically refer to any component or element of the present invention. It should not be construed as a limitation of the present invention.

[0031] In the present invention, terms such as "fixed connection", "connected", "connected" should be understood in a broad sense, which may mean a fixed connection, an integral connection or a detachable connection; it may be directly connected or indirectly connected through an intermediate medium. For those related scientific research or technical personnel in the field, the specific meaning of the above terms in the present invention can be determined according to specific circumstances and should not be construed as a limitation of the present invention.

[0032] Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0033] Embodiment 1

[0034] Embodiment 1 of the present invention introduces a high-voltage short degassing XLPE insulated power cable.

[0035] As Figure 1 shown, a high-voltage short degassing XLPE insulated power cable includes a conductor 1, a semiconductive low by-product XLPE conductor shielding layer 2, a low by-product XLPE insulation layer 3, a semiconductive low by-product XLPE insulation shielding layer 4, a transition buffer layer 5, a first semiconductive buffer layer 6, a metal shielding layer 7, a second semiconductive buffer layer 8, a metal sheath 9, an anticorrosion layer 10, an outer sheath 11, and an outer electrode 12, which are arranged in sequence from the inside to the outside.

[0036] The conductor 1, the semiconductive low by-product XLPE conductor shielding layer 2, the low by-product XLPE insulation layer 3, and the semiconductive low by-product XLPE insulation shielding layer 4 form the cable core.

[0037] Optionally, the conductor 1 is a compact round conductor or a sector-stranded and segmented conductor; both the compact round conductor and the sector-stranded and segmented conductor are formed by stranding single wires made of copper, aluminum, or aluminum alloy materials.

[0038] In this embodiment, the conductor 1 is a 1600 mm² tile-shaped five-segmented copper conductor.

[0039] In this embodiment, the semiconductive low by-product XLPE conductor shielding layer 2, the low by-product XLPE insulation layer 3, and the semiconductive low by-product XLPE insulation shielding layer 4 adopt a three-layer co-extrusion production process.

[0040] Among them, the semiconductive low by-product XLPE conductor shielding layer 2 is formed by extruding semiconductive low by-product XLPE shielding material on the outer surface of the conductor 1, the low by-product XLPE insulation layer 3 is formed by extruding low by-product XLPE insulation material on the outer surface of the semiconductive low by-product XLPE conductor shielding layer 2, and the semiconductive low by-product XLPE insulation shielding layer 4 is formed by extruding semiconductive low by-product XLPE shielding material on the outer surface of the low by-product XLPE insulation layer 3.

[0041] In this embodiment, the screw diameters of the extruders used for the three-layer co-extrusion production are 75 mm, 175 mm, and 90 mm respectively, the mesh numbers of the filter screens are 20 / 40 / 80 / 40 / 20, 40 / 80 / 150 / 300 / 150 / 80 / 40 / 20, 20 / 40 / 80 / 40 / 20 respectively, and the set partition temperatures are 80 o °C / 100 o °C / 110 o °C / 110 o °C, 115 o °C / 118 o °C / 115 o °C / 115 o °C / 115o C / 115 o C, 80 o C / 100 o C / 110 o C / 110 o C.

[0042] In the three - layer co - extrusion production, as Figure 2 shown, the pipeline for the gravity feeding of the insulating material is transformed by heating through an energized coil.

[0043] In this embodiment, the semi - conductive low - by - product XLPE conductor shielding layer 2, the low - by - product XLPE insulating layer 3, and the semi - conductive low - by - product XLPE insulating shielding layer 4 respectively adopt 75 / 175 / 90 type screw extruders.

[0044] In this embodiment, the transition buffer layer 5 adopts an activated carbon wrapping tape, which is wound around the outside of the cable core through a wrapping machine to absorb methane gas in the cable cross - linking by - products, effectively preventing the methane gas in the cable cross - linking by - products from escaping between the metal sheath 9 and the cable core.

[0045] In this embodiment, the metal shielding layer 7 is wound around the outside of the first semi - conductive buffer layer 6 by using a 96 - disk cage stranding machine; the metal shielding layer 7 includes a metal wire shield and a sensing optical fiber unit arranged at intervals, and the sensing optical fiber unit adopts a gas - sensing optical fiber, and the gas - sensing optical fiber is arranged along the length direction of the high - voltage short - degassing XLPE insulated power cable.

[0046] In this embodiment, the metal shielding layer 7 is wound in the order of uniformly inserting 8 optical fiber units among 40 aluminum wires. The outer diameter of the aluminum wire is 1.78 mm, and the outer diameter of the optical cable is 2.12 mm.

[0047] Outside the second semi - conductive buffer layer 8, a metal sheath 9 is coated. The metal sheath 9 can adopt a smooth aluminum sheath or a corrugated aluminum sheath; the thickness of the smooth aluminum sheath is set to 1.8 mm, and the thickness of the corrugated aluminum sheath is set to 2.0 mm - 2.3 mm.

[0048] In this embodiment, the anticorrosion layer 10 adopts a hot - melt adhesive material for bonding the metal sheath 9 and the outer sheath 11; the outer sheath 11 adopts a polyethylene - based material, a polypropylene - based material or a polyvinyl chloride material, and the thickness of the outer sheath 11 is set to 4 mm - 5 mm.

[0049] In this embodiment, a transition buffer layer with a methane gas absorption function is added, which can effectively prevent methane gas in the cable crosslinking by-products from escaping between the metal sheath and the cable core. A gas sensing optical fiber for monitoring the cable operation stability is added between the metal shielding layers. Raw materials for a semi-conductive low by-product XLPE conductor shielding layer, a low by-product XLPE insulation layer, and a semi-conductive low by-product XLPE insulation shielding layer are selected, enabling the power cable to innovatively possess the characteristics of environmental friendliness, directly reducing the concentration of cable crosslinking by-products at the source. At the same time, a three-layer co-extrusion process is adopted, and the pipeline for the gravity feeding of the insulating material is innovatively modified by heating treatment using an electric heating coil, effectively improving the crosslinking efficiency of the high-voltage power cable.

[0050] Embodiment 2

[0051] Embodiment 2 of the present invention introduces a manufacturing method for a high-voltage short degassing XLPE insulated power cable, which is used to manufacture the high-voltage short degassing XLPE insulated power cable introduced in Embodiment 1.

[0052] A manufacturing method for a high-voltage short degassing XLPE insulated power cable includes: sequentially arranging a transition buffer layer, a first semi-conductive buffer layer, a metal shielding layer, a second semi-conductive buffer layer, a metal sheath, an anti-corrosion layer, an outer sheath, and an outer electrode on the cable core; absorbing methane gas in the cable crosslinking by-products through the transition buffer layer, and monitoring the cable operation status through the gas sensing optical fiber arranged in the metal shielding layer; adopting a three-layer co-extrusion production in the cable core, and at the same time, modifying the pipeline for the gravity feeding of the insulating material by heating treatment using an electric heating coil.

[0053] As one or more implementation manners, the preparation process of the cable core is as follows:

[0054] Strand multiple single wires to form a conductor;

[0055] Wind a conductor tape around the conductor;

[0056] Pass through an XLPE three-layer co-extrusion suspension production line, and simultaneously extrude a semi-conductive low by-product XLPE conductor shielding layer, a low by-product XLPE insulation layer, and a semi-conductive low by-product XLPE insulation shielding layer.

[0057] As one or more implementation manners, for the three-layer co-extrusion production process of the cable core, the screw diameters of the extruders used are 75 mm, 175 mm, and 90 mm respectively, the mesh numbers of the filter screens are 20 / 40 / 80 / 40 / 20, 40 / 80 / 150 / 300 / 150 / 80 / 40 / 20, 20 / 40 / 80 / 40 / 20 respectively, and the set partition temperatures are 80 o °C / 100 o °C / 110 o °C / 110 o °C, 115o C / 118 o C / 115 o C / 115 o C / 115 o C / 115 o C, 80 o C / 100 o C / 110 o C / 110 o C; In the three-layer co-extrusion production, the pipeline for gravity feeding of insulating material is modified by heating it with an energized coil.

[0058] As one or more implementation methods, the transition buffer layer wrapping process is carried out by a wrapping machine.

[0059] As one or more implementation methods, the metal shielding layer is formed by stranding using a cage stranding machine.

[0060] As one or more embodiments, the aluminum sheath can be made by extrusion or welding; when the aluminum sheath uses a smooth aluminum sheath structure, the aluminum sheath is formed on the outside of the semi-conductive buffer water-blocking layer by extrusion or welding, and then the diameter is reduced to form a smooth aluminum sheath; when the aluminum sheath uses a corrugated aluminum sheath structure, the aluminum sheath is formed on the outside of the semi-conductive buffer water-blocking layer by extrusion or welding, and then the corrugated aluminum sheath is formed.

[0061] The above description is merely a preferred embodiment of this practice and is not intended to limit the scope of this practice. Various modifications and variations can be made to this practice by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this practice should be included within the protection scope of this practice.

Claims

1. A high-voltage short-circuit degassed XLPE insulated power cable, characterized in that, The cable includes a cable core, a transition buffer layer, and a metal shielding layer arranged from the inside out. The cable core comprises a conductor arranged sequentially from the inside out, and a semi-conductive low-by-product XLPE conductor shielding layer (extruded from a semi-conductive low-by-product XLPE shielding material onto the outer surface of the conductor), a low-by-product XLPE insulation layer (extruded from a low-by-product XLPE insulating material onto the outer surface of the semi-conductive low-by-product XLPE conductor shielding layer), and a semi-conductive low-by-product XLPE insulation shielding layer (extruded from a semi-conductive low-by-product XLPE shielding material onto the outer surface of the low-by-product XLPE insulation layer), all produced by three-layer co-extrusion. The extruder screw diameters used in the three-layer co-extrusion production are 75mm, 175mm, and 90mm, with filter mesh counts of 20 / 40 / 80 / 40 / 20, 40 / 80 / 150 / 300 / 150 / 80 / 40 / 20, and 20 / 40 / 80 / 40 / 20, respectively, and zone temperature settings of 80°C and 80°C, respectively. o C / 100 o C / 110 o C / 110 o C, 115 o C / 118 o C / 115 o C / 115 o C / 115 o C / 115 o C, 80 o C / 100 o C / 110 o C / 110 o C; In the three-layer co-extrusion production, the pipeline for gravity feeding of insulating material is modified by heating through an energized coil; a gas sensing optical fiber is arranged circumferentially in the metal shielding layer; the metal shielding layer includes spaced metal wire shielding and sensing optical fiber units, the sensing optical fiber unit adopts a gas sensing optical fiber, and the gas sensing optical fiber is arranged along the length direction of the high-voltage short degassed XLPE insulated power cable.

2. The high-voltage short-circuit degassed XLPE insulated power cable as described in claim 1, characterized in that, The transition buffer layer is wound around the outside of the cable core using a wrapping machine.

3. The high-voltage short-circuit degassed XLPE insulated power cable as described in claim 1, characterized in that, The conductor is a compacted round conductor or a stranded conductor; both the compacted round conductor and the stranded conductor are made of single wires made of copper, aluminum or aluminum alloy.

4. A high-voltage short-circuit degassed XLPE insulated power cable as described in claim 1, characterized in that, It also includes a first semiconductive buffer layer disposed between the transition buffer layer and the metal shielding layer, and a second semiconductive buffer layer, a metal sheath, an anti-corrosion layer, an outer protective layer and an outer electrode disposed sequentially outside the metal shielding layer.

5. A high-voltage short-circuit degassed XLPE insulated power cable as described in claim 4, characterized in that, The metal sheath is made of smooth aluminum or corrugated aluminum; the thickness of the smooth aluminum sheath is set to 1.8 mm or other thicknesses, and the thickness of the corrugated aluminum sheath is set to 2.0 mm to 2.3 mm.

6. A high-voltage short-circuit degassed XLPE insulated power cable as described in claim 4, characterized in that, The anti-corrosion layer is made of hot melt adhesive material, which is used to bond the metal sheath and the outer protective layer; the outer protective layer is made of polyethylene-based material, polypropylene-based material or polyvinyl chloride material, and the thickness of the outer protective layer is set to 4mm~5mm.

7. A method for manufacturing a high-voltage short-short degassed XLPE insulated power cable, used to manufacture the high-voltage short-short degassed XLPE insulated power cable as described in any one of claims 1-6, characterized in that, include: A transition buffer layer, a first semiconductive buffer layer, a metal shielding layer, a second semiconductive buffer layer, a metal sheath, an anti-corrosion layer, an outer sheath, and an outer electrode are sequentially arranged on the cable core. The transition buffer layer absorbs methane gas from the cross-linking byproducts of the cable, and the operating status of the cable is monitored by a gas sensing optical fiber installed in the metal shielding layer. The cable core is produced by three-layer co-extrusion, and the pipe for gravity feeding of the insulation material is modified by heating it with an energized coil.

8. A method for manufacturing a high-voltage short-circuit degassed XLPE insulated power cable as described in claim 7, characterized in that, The preparation process of the cable core is as follows: Multiple single wires are twisted together to form a conductor; Wrap conductor tape around the outside of the conductor; The XLPE three-layer co-extrusion overhead conveyor production line simultaneously extrudes a semi-conductive low-by-product XLPE conductor shielding layer, a low-by-product XLPE insulation layer, and a semi-conductive low-by-product XLPE insulation shielding layer.

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