Environment-friendly high-water-resistance impact-resistant medium-voltage power cable

Abstract

The utility model discloses an environmental protection type high water resistance impact resistance medium voltage power cable, including cable core and by the aluminium -plastic composite tape and sheath layer of setting outside cable core from inside to outside, the cable core is twisted and is formed by a plurality of insulated wire core, and the gap between insulated wire core fills water resistance filling rope, the insulated wire core includes conductor and by the conductor shield layer, insulating layer, insulating shield layer and metal composite shield layer of setting outside conductor from inside to outside, be equipped with water resistance expansion layer between insulating shield layer and metal composite shield layer, water resistance expansion layer is composed of superabsorbent fiber felt and water resistance powder, water resistance powder is through electrostatic spraying on polyester base superabsorbent fiber felt surface, superabsorbent fiber felt is polyester base superabsorbent fiber felt, be equipped with superabsorbent fiber felt layer between cable core and aluminium -plastic composite tape. The utility model has the advantages of good water resistance effect, good impact resistance.

Description

Technical Field

[0001] This utility model relates to power cables, specifically an environmentally friendly, high water-resistant, and impact-resistant medium-voltage power cable. Background Technology

[0002] Power cables are cables used for transmitting and distributing electrical energy. They are commonly used in urban underground power grids, power plant lead-out lines, internal power supply in industrial and mining enterprises, and underwater transmission lines across rivers and seas. The proportion of cables in power lines is gradually increasing. Power cables are cable products used in the main lines of power systems to transmit and distribute high-power electrical energy, including various voltage levels from 1-500KV and above. According to voltage level, they can be divided into medium and low voltage power cables (35 kV and below), high voltage cables (110 kV and above), ultra-high voltage cables (275-800 kV), and extra-high voltage cables (1000 kV and above). They can also be divided into AC cables and DC cables, and various types of insulated power cables. Medium voltage power cables refer to those that withstand electrical pressure of 35KV and below. Currently, most medium voltage power cables adopt a structure of conductor, insulation layer, shielding layer, and outer protective layer.

[0003] With economic development, the application of power cables has become more widespread, leading to stricter and more diverse requirements for their performance indicators. These include stringent requirements for tensile strength, impact toughness, operating temperature, aging resistance, and weather resistance. Continuously improving the overall performance of power cables is an urgent need for economic and social development. In high-humidity environments, water-blocking strips are sometimes used to improve the water-blocking effect of power cables. However, these cables often suffer from poor water-blocking performance, low strength, and inadequate impact toughness, causing inconvenience in practical use and even threatening people's lives and property. Therefore, improvements are needed to adapt to the diverse needs of the power cable market. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing an environmentally friendly, high water-blocking, impact-resistant medium-voltage power cable with good water-blocking and impact-resistant properties.

[0005] The technical objective of this utility model is achieved through the following technical solution:

[0006] An environmentally friendly, high water-resistant and impact-resistant medium-voltage power cable includes a cable core and an aluminum-plastic composite tape and a sheath layer arranged from the inside to the outside of the cable core; the cable core is made of multiple insulated wire cores twisted together, and the gaps between the insulated wire cores are filled with water-resistant filler rope;

[0007] The insulated core includes a conductor and, from the inside out, a conductor shielding layer, an insulation layer, an insulation shielding layer, and a metal composite shielding layer disposed outside the conductor; a water-blocking expansion layer is provided between the insulation shielding layer and the metal composite shielding layer; the water-blocking expansion layer is composed of superabsorbent fiber felt and water-blocking powder, the water-blocking powder being electrostatically sprayed onto the surface of polyester-based superabsorbent fiber felt; the superabsorbent fiber felt is polyester-based superabsorbent fiber felt; a superabsorbent fiber felt layer is provided between the cable core and the aluminum-plastic composite tape.

[0008] Preferably, the water-blocking powder is sodium acrylate-acrylamide copolymer powder.

[0009] Preferably, the superabsorbent fiber felt is a polyester-based superabsorbent fiber felt with a basis weight of 60-80 g / m².

[0010] Preferably, the metal composite shielding layer includes a copper wire layer and a copper strip layer; the copper wires of the copper wire layer are loosely wound on the water-blocking expansion layer, and the copper strip of the copper strip layer is wrapped around the copper wire layer, with the loose winding direction of the copper wires opposite to the wrapping direction of the copper strip.

[0011] Preferably, the sheath layer is a high-density polyethylene sheath layer.

[0012] Preferably, the conductor shielding layer of the insulated wire core is a semi-conductive conductor shielding layer.

[0013] Preferably, the insulation layer of the insulated wire core is a cross-linked polyethylene insulation layer.

[0014] Preferably, the insulating shielding layer of the insulating wire core is a semi-conductive insulating shielding layer.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] 1. This utility model features a multi-layered, effective water-blocking structure, including a water-blocking filling rope between the insulated cores, a water-blocking expansion layer between the insulating shielding layer and the metal composite shielding layer, and a super-absorbent fiber felt layer between the cable core and the aluminum-plastic composite tape. These water-blocking structures work together to form a comprehensive water-blocking barrier, effectively preventing moisture from penetrating the cable through various pathways. The water-blocking expansion layer is composed of super-absorbent fiber felt and water-blocking powder. The super-absorbent fiber felt is polyester-based, possessing excellent water absorption properties, rapidly absorbing and expanding upon penetration, blocking potential seepage channels. The water-blocking powder is electrostatically sprayed onto the surface of the super-absorbent fiber felt, further enhancing its water-blocking ability, allowing the water-blocking expansion layer to quickly form a robust water-blocking barrier upon encountering moisture. The super-absorbent fiber felt layer between the cable core and the aluminum-plastic composite tape absorbs any small amount of moisture that may seep in from the outer sheath, preventing further diffusion into the cable core, enhancing the overall synergistic effect of the cable's water-blocking system, and significantly improving the cable's waterproof performance.

[0017] Meanwhile, the aluminum-plastic composite tape provides excellent cushioning against impact. The water-blocking expansion layer and the superabsorbent fiber felt layer, both made of polyester-based superabsorbent fiber felt, possess superior cushioning performance. Due to their flexibility and elasticity, they act as a buffer when impacted, effectively reducing the impact force on the cable and protecting its internal structure. This structure disperses the impact force upon impact, preventing it from concentrating at a single point and causing fiber breakage, further enhancing the cable's overall impact resistance.

[0018] This invention has the advantages of good water-blocking effect and good impact resistance.

[0019] 2. The sheath layer is a high-density polyethylene (HDPE) sheath layer. HDPE has high impact strength, which can effectively resist external impacts and prevent the sheath from cracking or being damaged when the cable is subjected to impacts, compression, or other external forces, thereby protecting the internal structure of the cable from being affected. The use of a HDPE sheath layer further improves the impact resistance of this invention. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model;

[0021] Figure 2 yes Figure 1 A schematic diagram of the structure of the insulated wire core;

[0022] Reference numerals: 1-Conductor; 2-Conductor shielding layer; 3-Insulation layer; 4-Insulation shielding layer; 5-Water-blocking expansion layer; 6-Copper wire layer; 7-Copper tape layer; 8-Water-blocking filling rope; 9-Super absorbent fiber felt layer; 10-Aluminum-plastic composite tape; 11-Sheath layer. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] Example 1

[0027] like Figure 1 — Figure 2 As shown, an environmentally friendly, high water-blocking, and impact-resistant medium-voltage power cable includes a cable core, an aluminum-plastic composite tape 10 arranged from the inside out outside the cable core, and a sheath layer 11. The cable core is composed of multiple insulated wire cores twisted together, with water-blocking filler rope 8 filling the gaps between the insulated wire cores. The insulated wire core includes a conductor 1 and a conductor shielding layer 2, an insulation layer 3, an insulation shielding layer 4, and a metal composite shielding layer arranged from the inside out outside the conductor 1. A water-blocking expansion layer 5 is provided between the insulation shielding layer 4 and the metal composite shielding layer. The water-blocking expansion layer 5 is composed of superabsorbent fiber felt and water-blocking powder, with the water-blocking powder being electrostatically sprayed onto the surface of the superabsorbent fiber felt. The superabsorbent fiber felt is polyester-based superabsorbent fiber felt. A superabsorbent fiber felt layer 9 is provided between the cable core and the aluminum-plastic composite tape 10. This technical measure can effectively improve water-blocking performance and impact resistance. Specifically, the cable incorporates a multi-layered, effective water-blocking structure, including a water-blocking filler rope 8 between the insulated cores, a water-blocking expansion layer 5 between the insulating shielding layer 4 and the metal composite shielding layer, and a super-absorbent fiber felt layer 9 between the cable core and the aluminum-plastic composite tape 10. These water-blocking structures work together to form a comprehensive water-blocking barrier, effectively preventing moisture from penetrating the cable from different paths.

[0028] The water-blocking expansion layer 5 is composed of superabsorbent fiber felt and water-blocking powder. The superabsorbent fiber felt is made of polyester and has excellent water absorption properties, enabling it to quickly absorb intruding moisture and expand, blocking possible seepage channels. The water-blocking powder is electrostatically sprayed onto the surface of the superabsorbent fiber felt, further enhancing its water-blocking ability, allowing the water-blocking expansion layer 5 to quickly form a robust water-blocking barrier when exposed to moisture. The superabsorbent fiber felt layer 9, located between the cable core and the aluminum-plastic composite tape 10, can absorb small amounts of moisture that may seep in from the outer sheath, preventing moisture from continuing to diffuse into the cable core. This enhances the overall synergistic effect of the cable's water-blocking system, significantly improving the cable's waterproof performance and making it suitable for various humid environments, such as underground pipelines and locations near water sources.

[0029] The aluminum-plastic composite tape 10 has a good buffering effect against impact. When the cable is subjected to external impact, such as being hit by tools during construction or being hit by falling objects during operation, the aluminum-plastic composite tape 10 can absorb and disperse some of the impact energy, prevent sharp objects from directly piercing the cable, and reduce the direct damage of impact force to the internal structure of the cable.

[0030] Meanwhile, the water-blocking expansion layer 5 and the superabsorbent fiber felt layer 9, both made of polyester-based superabsorbent fiber felt, possess excellent buffering performance. Due to their flexibility and elasticity, they act as a buffer pad when impact forces act on the cable, effectively reducing the impact force on the cable and protecting the internal structure. When subjected to impact, this structure can disperse the impact force, preventing the impact force from concentrating at a single point and causing fiber breakage, further enhancing the overall impact resistance of the cable.

[0031] In practice, the cable core is made up of three insulated wires twisted together.

[0032] The insulated core includes a conductor 1 and a conductor shielding layer 2, an insulation layer 3, an insulation shielding layer 4, and a metal composite shielding layer disposed from the inside out outside the conductor 1.

[0033] In practical implementation, the conductor shielding layer 2 is a semi-conductive conductor shielding layer. The semi-conductive conductor shielding layer has a conductivity similar to that of the conductor 1, which can closely adhere to the surface of the conductor 1, effectively uniformly distribute the electric field around the conductor 1, avoid electric field concentration, and reduce the risk of partial discharge.

[0034] In practical implementation, insulation layer 3 is a cross-linked polyethylene (XLPE) insulation layer. XLPE insulation layer has high breakdown strength and good electrical insulation properties, effectively isolating conductor 1 from external electrical contact and ensuring the stability and safety of power transmission. XLPE has high heat resistance, enabling long-term stable operation at higher temperatures, thus improving the cable's operating temperature range. XLPE has good mechanical properties, including high tensile strength and elongation at break, enabling it to withstand the mechanical stresses that the cable may encounter during laying and use.

[0035] In practical implementation, the insulating shielding layer 4 is a semi-conductive insulating shielding layer. The semi-conductive insulating shielding layer has a conductivity similar to that of the insulating layer 3, allowing it to closely adhere to the surface of the insulating layer 3, effectively uniformly distributing the electric field on the surface of the insulating layer 3, and further reducing the risk of partial discharge. It can prevent electrical treeing aging caused by electric field concentration on the surface of the insulating layer 3, improving the insulation performance and service life of the cable.

[0036] In practical implementation, the water-blocking expansion layer 5 consists of superabsorbent fiber felt and water-blocking powder. The water-blocking powder is electrostatically sprayed onto the surface of the polyester-based superabsorbent fiber felt; the superabsorbent fiber felt is polyester-based. In actual use, the water-blocking powder side of the water-blocking expansion layer 5 is the inner layer, and the superabsorbent fiber felt side is the outer layer. The superabsorbent fiber felt is a polyester-based superabsorbent fiber felt with a basis weight of 60-80 g / m².

[0037] Specifically, the water-blocking powder is sodium acrylate-acrylamide copolymer powder. Using sodium acrylate-acrylamide copolymer powder as a water-blocking powder significantly improves the water-blocking performance of the cable. It can quickly absorb moisture and expand, forming a gel-like substance that blocks seepage channels, enhancing the cable's waterproof reliability, and is particularly suitable for humid environments. The gel-like substance formed after the sodium acrylate-acrylamide copolymer powder absorbs water and expands has a certain degree of elasticity and toughness, which can act as a buffer when subjected to impact, absorbing and dispersing impact energy and reducing damage to the internal structure of the cable. When combined with polyester-based superabsorbent fiber felt, the formed water-blocking expansion layer 5 has good impact resistance, effectively resisting external impacts and collisions, protecting the cable's conductor 1 and insulation layer 3.

[0038] Polyester-based superabsorbent fiber felt is a superabsorbent fiber material based on polyester, generally woven from superabsorbent fibers and polyester yarn. It has advantages such as strong water absorption, high tensile strength, moderate elongation, fast water absorption speed, and high expansion rate.

[0039] In practical implementation, the metal composite shielding layer includes a copper wire layer 6 and a copper strip layer 7. The copper wires of the copper wire layer 6 are loosely wound around the water-blocking expansion layer 5, while the copper strip of the copper strip layer 7 is wrapped around the copper wire layer, with the loose winding direction of the copper wires opposite to the wrapping direction of the copper strip. This technical measure enhances the water barrier; the combination of the copper wire layer 6 and the copper strip layer 7 provides a robust physical barrier for the cable, further enhancing its water-blocking capability. The tight wrapping of the copper strip layer 7 effectively prevents moisture from penetrating into the cable's interior, forming a multi-layered water-blocking system together with the water-blocking expansion layer 5. High conductivity and mechanical strength are also provided; both the copper wire layer 6 and the copper strip layer 7 are made of copper, possessing excellent conductivity and high mechanical strength. The loose winding structure of the copper wire layer 6 provides a certain degree of flexibility while also enhancing the cable's tensile strength. The tight wrapping of the copper strip layer 7 further improves the overall strength and rigidity of the cable, enabling it to withstand greater mechanical stress. The copper wire 6 is wound in the opposite direction to the copper tape 7. This reverse wrapping method makes the bond between the copper wire layer 6 and the copper tape layer 7 tighter, enhancing the integrity and stability of the metal composite shielding layer and improving the cable's torsional and bending fatigue resistance. The tight wrapping of the copper tape layer 7 effectively disperses impact force, preventing the impact force from concentrating at a single point and causing cable damage. When the cable is subjected to external impact, the copper tape layer 7 can distribute the impact force over a larger area, reducing damage to the internal structure. Working synergistically with other structural layers such as the water-blocking expansion layer 5 and the aluminum-plastic composite tape 10, it forms an integrated protective system, improving the cable's impact resistance and ensuring that the cable maintains good performance even when subjected to external impact.

[0040] The sheath layer 11 is a high-density polyethylene (HDPE) sheath layer. HDPE has high impact strength, effectively resisting external impacts and preventing sheath breakage or damage when the cable is subjected to impacts, compression, or other external forces, thus protecting the internal structure of the cable. Its impact strength is typically above 50 kJ / m², capable of withstanding significant impact forces. HDPE also possesses good flexibility and toughness, allowing the sheath to deform to a certain extent upon impact, thereby absorbing and dispersing impact energy and reducing the direct impact force on the internal structure of the cable. The HDPE sheath layer 11 is usually used in conjunction with other structural layers such as a metal composite shielding layer. The metal composite shielding layer provides additional mechanical strength and impact resistance, forming a unified protective system with the HDPE sheath layer 11. The combination of the rigidity of the metal shielding layer and the toughness of the HDPE sheath layer 11 better resists external impacts and collisions, ensuring the cable maintains good performance even under external impact. The inclusion of a high-density polyethylene sheath layer further enhances the impact resistance of this invention.

[0041] A method for manufacturing an environmentally friendly, high water-resistance, and impact-resistant medium-voltage power cable includes the following process steps:

[0042] S1. To make conductor 1, use a wire drawing machine to draw a round single wire, and use a frame stranding machine to make conductor 1 by regular stranding or irregular stranding.

[0043] In this embodiment, a double-head continuous annealing wire drawing machine is used to stretch and shape a φ8 copper rod into 61 single wires with a diameter of 2.9mm through 6-8 passes using dies. These single wires are then stranded into strands using a 60-disc frame stranding machine in a 1+6+12+18+24 layered compaction structure, forming a compacted round copper conductor. Conductor 1 has a diameter of 23.4mm (compaction coefficient ≥0.90) and a DC resistance not exceeding 0.0470Ω / km. In specific implementations, the diameter of the single wires, the number of single wires, and the stranding method are adjusted according to the specifications of the power cable.

[0044] S2. The conductor shielding layer 2, insulation layer 3 and insulation shielding layer 4 are extruded and wrapped on the conductor 1 using a CCV overhead conveyor three-layer co-extrusion cross-linking machine to form a wire core.

[0045] In this embodiment, the extrusion parameters are as follows: temperature: conductor shielding layer 2150℃, insulation layer 3170℃, insulation shielding layer 4155℃; crosslinking: nitrogen pressure 1.0 MPa.

[0046] During extrusion, the conductor shield (ultra-smooth semi-conductive cross-linked polymer) with a nominal thickness of 0.8mm, the cross-linked polyethylene insulation (ultra-clean XLPE, 10kV cable insulation thickness ≥4.5mm), and the insulation shield (peelable semi-conductive layer) with a nominal thickness of 0.8mm are produced on a CCV catenary three-layer co-extrusion cross-linking production line.

[0047] S3. After the wire core exits the machine head, nitrogen pressurization and zone heating are used to gradually reduce the heating temperature so that the conductor shielding layer 2, insulation layer 3 and insulation shielding layer 4 are effectively cross-linked.

[0048] In this embodiment, the nitrogen pressurization and heating crosslinking is divided into 8 sections, a water vapor transition section, and a water-cooling section. The temperatures of each section in the nitrogen pressurization crosslinking area are as follows:

[0049] .

[0050] S4. Wrap a water-blocking expansion layer 5 around the surface in step S3.

[0051] In this embodiment, an acrylic water-blocking expansion layer 5 is prepared by spraying an acrylic water-blocking powder with a particle size ≤50μm onto the inner layer of a polyester-based superabsorbent fiber felt. Further, a sodium acrylate-acrylamide copolymer (particle size 30μm) is electrostatically sprayed (thickness 0.2mm); the overlap rate of the polyester-based superabsorbent fiber felt is ≥30%, and the tension is 15N.

[0052] S5. On the copper wire shielding machine, 0.3mm copper wire is loosely wound onto the water-blocking expansion layer 5 to form a copper wire layer 6; then, copper tape is wrapped around the outside of the copper wire layer 6 to form a copper tape layer 7, and the wrapping direction of the copper tape is opposite to the loose winding direction of the copper wire to form a metal composite shielding layer; thus, an insulated wire core is obtained.

[0053] S6: Prepare the cable core by using a disc stranding machine to strand the insulated wire cores into a cable; during the stranding process, water-blocking filling rope 8 is installed in the gaps formed between the insulated wire cores.

[0054] S7: Wrap the super absorbent fiber felt layer 9 and aluminum-plastic composite tape 10 around the outside of the cable core in sequence;

[0055] S8. An outer sheath layer 11 is extruded onto the aluminum-plastic composite belt 10.

[0056] This medium-voltage power cable is manufactured using green technology, with halogen-free production throughout the entire process, and the waste sheath can be recycled (recycling rate ≥90%).

[0057] The technical solutions provided by the embodiments of this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of this utility model. The description of the above embodiments is only for helping to understand the principles of the embodiments of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. An environmentally friendly, high water-resistance, and impact-resistant medium-voltage power cable, characterized in that: This includes the cable core, as well as the aluminum-plastic composite tape and sheath layer arranged from the inside out on the outside of the cable core; The cable core is made of multiple insulated wire cores twisted together, and the gaps between the insulated wire cores are filled with water-blocking filler rope; The insulated core includes a conductor and, from the inside out, a conductor shielding layer, an insulation layer, an insulation shielding layer, and a metal composite shielding layer disposed outside the conductor; a water-blocking expansion layer is provided between the insulation shielding layer and the metal composite shielding layer; The water-blocking expansion layer is composed of superabsorbent fiber felt and water-blocking powder. The water-blocking powder is electrostatically sprayed onto the surface of polyester-based superabsorbent fiber felt. The superabsorbent fiber felt is polyester-based superabsorbent fiber felt. A superabsorbent fiber felt layer is provided between the cable core and the aluminum-plastic composite tape.

2. The environmentally friendly high water resistance and impact-resistant medium-voltage power cable according to claim 1, characterized in that, The water-blocking powder is sodium acrylate-acrylamide copolymer powder.

3. The environmentally friendly high water resistance and impact-resistant medium-voltage power cable according to claim 1, characterized in that, The superabsorbent fiber felt is a polyester-based superabsorbent fiber felt with a basis weight of 60-80 g / m².

4. The environmentally friendly high water resistance and impact-resistant medium-voltage power cable according to claim 1, characterized in that, The metal composite shielding layer includes a copper wire layer and a copper strip layer; the copper wires of the copper wire layer are loosely wound on the water-blocking expansion layer, and the copper strip of the copper strip layer is wrapped around the copper wire layer, with the loose winding direction of the copper wires opposite to the wrapping direction of the copper strip.

5. The environmentally friendly high water resistance and impact-resistant medium-voltage power cable according to claim 1, characterized in that, The sheath layer is a high-density polyethylene sheath layer.

6. The environmentally friendly high water resistance and impact-resistant medium-voltage power cable according to claim 1, characterized in that, The conductor shielding layer of the insulated wire core is a semi-conductive conductor shielding layer.

7. The environmentally friendly high water resistance and impact-resistant medium-voltage power cable according to claim 1, characterized in that, The insulation layer of the insulated wire core is a cross-linked polyethylene insulation layer.

8. The environmentally friendly high water resistance and impact-resistant medium-voltage power cable according to claim 1, characterized in that, The insulating shielding layer of the insulated wire core is a semi-conductive insulating shielding layer.

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