A thin-walled extruded insulated cellular filled low voltage power cable for light weight fans

Abstract

The application relates to a thin-wall extruded insulation honeycomb-filled light-weight low-voltage power cable for a fan, belonging to the field of cables, which comprises a cable core, a third wrapping layer arranged outside the cable core and an outer sheath arranged outside the third wrapping layer, and the cable-forming section diameter ratio of the cable core is 12-26 times; the cable core comprises a wire core and a filling strip, the wire core and the filling strip are twisted and abutted, the filling strip is honeycomb-shaped, the honeycomb unit size is 0.5-10 mm, and the unit volume mass is 0.1-0.3 g / cm 3 ; the wire core comprises a conductor, an insulation layer and a second wrapping layer arranged in sequence from inside to outside, the conductor is a five-type circular structure, the cross-sectional area is 0.34-16 mm 2 . The low-voltage power cable for a fan has a thin insulation layer, light weight, good mechanical strength, can improve the tensile, compressive and bending resistance of the cable, optimizes temperature distribution and reduces the risk of thermal aging.

Description

Technical Field

[0001] This application relates to the technical field of cables, and in particular to a thin-walled extruded insulated honeycomb-filled lightweight low-voltage power cable for wind turbines. Background Technology

[0002] Power cables, like the winding steel veins beneath a city, crisscross to form the lifeline of the power system, tirelessly delivering surging energy to modern civilization day and night. Currently, most cables use polypropylene filler rope as the filler material. As a crucial material in cable assembly, polypropylene filler rope is primarily used to fill the gaps between conductors to improve the cable's roundness, mechanical cushioning performance, and impact resistance. With the increasing demand for lightweight, corrosion-resistant, and electrical insulation properties in the cable industry, polypropylene, due to its excellent chemical stability, low density, and good processing performance, is gradually replacing traditional materials such as polyethylene filler strips, hemp rope, and cotton yarn. However, existing technologies have significant shortcomings in practical applications, particularly in terms of insufficient water-blocking and environmental performance, which urgently require patented innovation to address. Polypropylene filler rope typically adds inorganic fillers such as calcium carbonate and talc to reduce costs and improve rigidity, but these fillers themselves are hygroscopic, especially in high-temperature and high-humidity environments, where they absorb moisture, leading to the formation of microchannels within the material and reducing water-blocking performance.

[0003] An announcement (No. 202694942U) discloses a watertight cross-linked polyethylene insulated polyurethane sheathed shielded power cable. This cable comprises a tinned copper conductor, a cross-linked polyethylene insulation layer, water-blocking yarn filler, a water-blocking tape, a tinned copper wire leakage conductor, an aluminum-plastic composite tape shielding layer, a water-blocking wrapping tape, and a polyether-type polyurethane sheath. The tinned copper conductor and its outer cross-linked polyethylene insulation layer form the insulated core. Water-blocking yarn filler is located between the insulated core and the water-blocking tape. A tinned copper wire leakage conductor is located within the water-blocking tape. Outside the water-blocking tape is the aluminum-plastic composite tape shielding layer, outside the aluminum-plastic composite tape shielding layer is the water-blocking wrapping tape, and outside the water-blocking wrapping tape is the polyether-type polyurethane sheath. However, this cable has a tinned copper wire leakage conductor within the water-blocking tape. During use, if water enters the cable, the tinned copper wire leakage conductor is easily oxidized and damaged. Using an aluminum-plastic composite tape as the waterproof layer, with both the inner and outer layers being water-blocking tapes, lacks an adhesive layer, and its strength cannot be guaranteed. Therefore, its structural stability and waterproof performance cannot be guaranteed during use.

[0004] A lightweight, waterproof, and corrosion-resistant overhead cable disclosed in announcement number 203573715U includes several aluminum alloy conductors. These conductors are successively covered with a fiberglass braided layer and a polyester rubber insulation layer to form an insulated core. The insulated core is centered on an elastic post extruded from polyurethane rubber material, with a phosphated steel wire at its center. The cable core is subsequently covered with an aluminum-plastic composite tape wrapping layer, a polyester rubber outer sheath layer, and an epoxy resin layer and a polyurethane waterproof coating forming a waterproof membrane on the outer wall of the polyester rubber outer sheath layer. However, the polyurethane waterproof coating on the outer sheath surface is easily damaged and detached during transportation and installation, resulting in a loss of water-blocking performance. Utility Model Content

[0005] To address the aforementioned issues, this application provides a thin-walled extruded insulated honeycomb-filled lightweight low-voltage power cable for wind turbines.

[0006] This application provides a thin-walled extruded insulated honeycomb-filled lightweight low-voltage power cable for fans, which adopts the following technical solution:

[0007] A thin-walled extruded insulated honeycomb-filled lightweight low-voltage power cable for wind turbines includes a cable core, a third wrapping layer disposed outside the cable core, and an outer sheath disposed outside the third wrapping layer. The cable core has a pitch ratio of 12-26. The cable core includes conductors and filler strips, which are twisted and abutted together. The filler strips are honeycomb-shaped, with a honeycomb unit size of 0.5-10 mm and a unit volume mass of 0.1-0.3 g / cm³. 3 The wire core comprises, from the inside out, a conductor, an insulation layer, and a second wrapping layer. The conductor is a stranded circular structure of five types with a cross-sectional area of ​​0.34-16 mm². 2 .

[0008] Optionally, the thickness of the insulating layer is 0.2-1.2 mm.

[0009] Optionally, the nominal thickness of the outer sheath is not less than 0.8-1.2 mm, and the thickness of the thinnest point is not less than 85%-0.1 mm of the nominal thickness.

[0010] By adopting the above technical solution, the filler strip of this application is honeycomb-shaped, prepared by a two-stage extrusion process plus a foaming process. The honeycomb structure is formed by arranging hexagonal or polygonal units to form a mechanically optimal topological configuration. Its specific stiffness (strength / density ratio) is significantly higher than that of traditional solid structures, and its shear strength is excellent, making it suitable for dynamic load scenarios. This structure can precisely control the unit size to 0.5-10mm by arranging it like alternating pins, achieving local reinforcement design. The honeycomb filler strip generated by the foaming process can balance the strength distribution of the X / Y / Z axes, avoiding the anisotropy problem caused by traditional processes. It exhibits uniform stress dispersion ability in compression tests, and the compressive strength attenuation rate is less than 30% (10). 4 (After one cycle); the porosity of the honeycomb structure reduces the weight of the filler strip by more than 50% while maintaining more than 90% of the effective support area. In this application, the filler material is honeycomb polypropylene, and its unit volume mass after foaming is only 0.1-0.3 g / cm³. 3 Compared to existing conventional filler materials, this reduces costs by more than 70%. Furthermore, testing has shown that the honeycomb structure of this application can increase the cable's tensile strength (Rm) by more than 30%, compressive strength by more than 50%, and bending resistance by more than double. In addition, the cavities of the honeycomb structure can optimize the cable's temperature distribution, reducing the temperature gradient by more than 20%, thereby delaying aging.

[0011] In summary, the low-voltage power cable for wind turbines proposed in this application enhances its mechanical strength, improves its tensile, compressive, and bending resistance by utilizing a honeycomb structure, optimizes temperature distribution, delays aging, and exhibits good safety and stability in use.

[0012] Optionally, a first wrapping layer is further provided between the conductor and the insulating layer.

[0013] Optionally, the first wrapping layer is formed by wrapping a polyamide-imide composite tape with a nominal thickness of 0.13 mm and a wrapping overlap rate of not less than 25%.

[0014] By adopting the above technical solution, the addition of the first wrapping layer enhances the mechanical bonding strength between the conductor and the insulation layer, effectively preventing the insulation layer from shifting or falling off during use. This structural design improves the electrical insulation reliability of the cable, provides an additional protective barrier for the insulation layer, and reduces the impact of external factors on the insulation performance. The presence of the first wrapping layer can also improve the bending performance of the cable, enabling it to maintain stable electrical and mechanical properties under frequent bending or stress conditions.

[0015] Optionally, the conductor is one of five types of circular structures obtained by twisting tin-plated copper monofilaments, with a twisting pitch ratio of 21-32 times.

[0016] By adopting the above technical solution, the cable conductor uses a five-type circular structure formed by single stranding of tin-plated copper monofilaments, with a stranding pitch ratio ranging from 21 to 32 times. This structure effectively improves the conductor's flexibility while maintaining good electrical performance and mechanical strength. Tin plating not only enhances the conductor's oxidation resistance and extends its service life but also improves its solderability and conductivity. The stranding design makes the stress distribution more uniform during bending and stretching, reducing the risk of breakage caused by localized stress concentration. This makes it particularly suitable for scenarios requiring frequent movement or bearing dynamic loads, such as internal wiring of wind turbines.

[0017] Optionally, when the cross-sectional area of ​​the conductor is 0.34-6 mm² 2 At that time, the cable core's cable section diameter ratio was 12-21 times.

[0018] By adopting the above technical solutions, the structural compactness of the cable can be effectively optimized. A smaller cabling section diameter ratio helps reduce the overall diameter and weight of the cable while maintaining good mechanical and electrical properties. This design is particularly suitable for scenarios requiring miniaturization and lightweighting, such as internal wiring in wind turbines, reducing material costs and installation difficulty while ensuring cable performance.

[0019] Optionally, when the cross-sectional area of ​​the conductor is 6-16 mm² 2 At that time, the cable core's cable section diameter ratio was 21-26 times.

[0020] By adopting the above technical solutions, the overall structural layout of the cable can be optimized. This design effectively improves the mechanical properties while ensuring the cable's electrical performance, resulting in better stability and resistance to deformation under external stress. Specifically, a larger cabling pitch ratio helps to evenly distribute the stress generated during stranding, reducing localized stress concentration and thus lowering the risk of fatigue under dynamic operating conditions. Furthermore, this design also considers the cable's flexibility and tensile strength, making it suitable for scenarios requiring frequent movement or subjected to external forces, such as wind turbine cables.

[0021] Optionally, the second wrapping layer is formed by wrapping a polyamide-imide composite tape with a nominal thickness of 0.13 mm and a wrapping overlap rate of not less than 25%.

[0022] By adopting the above technical solutions, the mechanical strength and electrical insulation performance of the cable can be significantly improved. Specific effects include: enhanced tensile strength and improved overall structural stability; effective prevention of insulation layer erosion by external environmental factors, extending cable service life; and the high dielectric strength of the polyamide-imide composite tape ensuring safe operation of the cable under high voltage.

[0023] Optionally, the third wrapping layer is formed by wrapping a polypropylene tape with a nominal thickness of 0.12 mm and a wrapping overlap rate of not less than 5%.

[0024] By adopting the above technical solution, this application utilizes the lightweight properties of polypropylene tape to effectively reduce the overall weight of the cable. Simultaneously, the high transparency and excellent water vapor barrier properties of polypropylene material enhance the cable's protective performance. Furthermore, a wrapping overlap rate of no less than 5% ensures the structural integrity and sealing effect of the wrapping layer, further enhancing the cable's mechanical strength and environmental adaptability.

[0025] In summary, this application includes at least one of the following beneficial technical effects:

[0026] 1. The low-voltage power cable for wind turbines in this application achieves lightweight filling, reduces tower load and improves vibration resistance. The honeycomb structure buffers external impacts, and the flexibility of the thin-wall design can withstand dynamic stresses such as wind turbine blade vibration and wind sway, reducing the risk of cable fatigue fracture.

[0027] 2. The specific structure of the low-voltage power cable for wind turbines authorized under this license ensures the requirements for electrical and mechanical performance of the cable. The concave structure buffers external impacts, and the flexibility of the thin-wall design allows it to withstand dynamic stresses such as wind turbine blade vibration and wind sway, reducing the risk of cable fatigue fracture.

[0028] 3. The chemical inertness of the polypropylene and the airtightness of the honeycomb structure used in the low-voltage power cable for wind turbines of this application enable the cable to maintain stable performance in humid, salt spray or chemically corrosive environments, making it particularly suitable for offshore or industrial wind turbine applications. Attached Figure Description

[0029] Figure 1 This is a cross-sectional view of an embodiment of this application.

[0030] Explanation of reference numerals in the attached diagram: 1. Cable core; 11. Wire core; 111. Conductor; 112. First wrapping layer; 113. Insulation layer; 114. Second wrapping layer; 12. Filler strip; 2. Third wrapping layer; 3. Outer sheath. Detailed Implementation

[0031] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0032] This application discloses a low-voltage power cable for thin-walled extruded insulated honeycomb-filled lightweight fans.

[0033] Reference Figure 1A thin-walled extruded insulated honeycomb-filled lightweight low-voltage power cable for fans is disclosed, comprising a cable core 1, which includes conductors 11 and filler strips 12, formed by twisting and abutting the conductors 11 and filler strips 12. The filler strips 12 are honeycomb-shaped, with a honeycomb unit size of 0.5-10 mm and a unit volume mass of 0.1-0.3 g / cm³. 3 The wire core 11 includes a conductor 111, an insulation layer 113, and a second wrapping layer 114 arranged sequentially from the inside out. The conductor 111 has a stranded circular structure of five types with a cross-sectional area of ​​0.34-16 mm². 2 The stranding pitch ratio is 21-32 times. A first wrapping layer 112 is provided on the outside of conductor 111, consisting of a polyamide-imide composite tape with a nominal thickness of 0.13 mm and a wrapping overlap rate of not less than 25%. An insulation layer 113 is provided outside the first wrapping layer 112, extruded from environmentally friendly water-tree resistant cross-linked polyethylene insulation material. A second wrapping layer 114 is wrapped around the insulation layer 113, consisting of a polyamide-imide composite tape with a nominal thickness of 0.13 mm and a wrapping overlap rate of not less than 25%. When the cross-sectional area of ​​conductor 111 is 0.34-6 mm²... 2 At that time, the cable core 1 has a cable pitch ratio of 12-21 and a cross-sectional area of ​​6-16 mm². 2 At that time, the cable core 1 has a cable section diameter ratio of 21-26 times.

[0034] Filler strip 12 is made from polypropylene, talc, calcium carbonate, glass fiber, phthalates, ethylene-octene copolymer, melamine polyphosphate, and pentaerythritol ester. The polypropylene used is a copolymer PP with a melt index (MI) of 10-60 g / 10 min to ensure processing fluidity and foaming uniformity. Talc accounts for 10-20 parts by weight, calcium carbonate 5-15 parts by weight, and glass fiber 3-8 parts by weight, and surface treatment with a silane coupling agent enhances the interfacial bonding with PP. The composite foaming agent consists of nitrogen, carbon dioxide, and sodium citrate. The primary extruder completes the plasticization of the raw material, the secondary extruder injects the composite foaming agent and cools it, and the cable core 1 is extruded through the die. The outer side of the cable core 1 is provided with a third wrapping layer 2, which is made of polypropylene tape with a nominal thickness of 0.12mm and a wrapping overlap rate of not less than 5%. The outer side of the third wrapping layer 2 is provided with an outer sheath 3, which is made of low smoke halogen-free flame retardant high-molecular polyurethane resistant to strong acid corrosion, with a nominal thickness of not less than 0.8-1.2mm and a minimum thickness of not less than 85%-0.1mm of the nominal thickness.

[0035] The cable obtained by this application has a thin insulation layer, is lightweight, and has good mechanical strength. It can improve the cable's tensile, compressive, and bending resistance, optimize temperature distribution, and reduce the risk of thermal aging. The product test results are as follows:

[0036]

[0037]

[0038] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A thin-walled extruded insulated honeycomb-filled lightweight low-voltage power cable for fans, characterized in that, The cable core (1) includes a third wrapping layer (2) disposed on the outside of the cable core (1) and an outer sheath (3) disposed on the outside of the third wrapping layer (2). The cable core (1) has a cable pitch ratio of 12-26 times. The cable core (1) includes a wire core (11) and a filler strip (12). The wire core (11) and the filler strip (12) are twisted together and abut against each other. The filler strip (12) is honeycomb-shaped, with a honeycomb unit size of 0.5-10 mm and a unit volume mass of 0.1-0.3 g / cm³. 3 ; The wire core (11) includes a conductor (111), an insulation layer (113), and a second wrapping layer (114) arranged sequentially from the inside to the outside. The conductor (111) has a five-dimensional circular structure with a cross-sectional area of ​​0.34-16 mm². 2 .

2. The low-voltage power cable for thin-walled extruded insulated honeycomb-filled lightweight fans according to claim 1, characterized in that, The thickness of the insulating layer (113) is 0.2-1.2 mm.

3. The thin-walled extruded insulated honeycomb-filled lightweight low-voltage power cable for fans according to claim 1, characterized in that, The nominal thickness of the outer sheath (3) is not less than 0.8-1.2 mm, and the thickness of the thinnest point is not less than 85%-0.1 mm of the nominal thickness.

4. The thin-walled extruded insulated honeycomb-filled lightweight low-voltage power cable for fans according to claim 1, characterized in that, A first wrapping layer (112) is also provided between the conductor (111) and the insulating layer (113).

5. The thin-walled extruded insulated honeycomb-filled lightweight low-voltage power cable for fans according to claim 4, characterized in that, The first wrapping layer (112) is made of a polyamide-imide composite tape with a nominal thickness of 0.13 mm and a wrapping overlap rate of not less than 25%.

6. The low-voltage power cable for thin-walled extruded insulated honeycomb-filled lightweight fan according to claim 1, characterized in that, The conductor (111) is a circular structure of five types obtained by one stranding of tin-plated copper monofilaments, with a stranding diameter range of 21-32 times.

7. The thin-walled extruded insulated honeycomb-filled lightweight low-voltage power cable for fans according to claim 1, characterized in that, When the cross-sectional area of ​​the conductor (111) is 0.34-6 mm 2 At that time, the cable core (1) has a cable section diameter ratio of 12-21 times.

8. The thin-walled extruded insulated honeycomb-filled lightweight low-voltage power cable for fans according to claim 7, characterized in that, When the cross-sectional area of ​​the conductor (111) is 6-16 mm² 2 At that time, the cable core (1) has a cable section diameter ratio of 21-26 times.

9. The low-voltage power cable for thin-walled extruded insulated honeycomb-filled lightweight fan according to claim 1, characterized in that, The second wrapping layer (114) is made of a polyamide-imide composite tape with a nominal thickness of 0.13 mm and a wrapping overlap rate of not less than 25%.

10. The thin-walled extruded insulated honeycomb-filled lightweight low-voltage power cable for fans according to claim 1, characterized in that, The third wrapping layer (2) is made of polypropylene tape with a nominal thickness of 0.12 mm and a wrapping overlap rate of not less than 5%.

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