High-distortion-resistant and high-temperature-resistant cable for wind power generation

Abstract

The invention relates to the technical field of cable manufacturing, in particular to a high-distortion-resistance and high-temperature-resistance cable for wind power generation, which comprises a multi-layer anti-torsion conductor core, a dynamic compensation insulating layer, a three-dimensional braided shielding layer, a spiral heat dissipation channel layer and a sheath which are sequentially arranged from inside to outside, the multi-level anti-torsion conductor core adopts a tinned copper alloy conductor with a five-level stranded structure, the dynamic compensation insulating layer adopts a ceramic silicone rubber and polyolefin nano composite material, and the spiral heat dissipation channel layer is formed by spirally winding hollow metal wires. The defects in the prior art are overcome, the five-stage heterogeneous material twisting design is adopted, the internal stress counteracting effect is generated through the elasticity modulus difference of the materials, the ceramic silicone rubber forms a porous ceramic framework at the temperature of 300 DEG C, meanwhile, pores are filled with polyolefin melt, and the insulation resistance retention rate is larger than 95% after 200 times of thermal shock circulation; and a Venturi effect is formed between the hollow metal wire layers, so that the heat dissipation efficiency can be improved by utilizing external wind.

Description

Technical Field

[0001] The present invention relates to the technical field of cable manufacturing, and specifically to a highly twist-resistant and high-temperature-resistant cable for wind power generation. Background Art

[0002] Traditional wind power generation cables mostly adopt a concentric stranded structure with a homogeneous copper conductor. Its stranding pitch is single, and the stranding directions of each layer are the same. Such a structure is prone to stress concentration under long-term dynamic torsion conditions of ±720° / m, resulting in a conductor wire breakage rate exceeding 5% per 10,000 cycles, and it is difficult to meet the 20-year design life requirement of offshore wind power.

[0003] However, existing insulating layers mostly use single silicone rubber or cross-linked polyethylene. Although silicone rubber is heat-resistant, its tear strength is low, and microcracks are easily generated after dynamic bending; while cross-linked polyethylene is prone to plastic deformation at high temperatures, resulting in a 30%-50% decrease in insulation resistance.

[0004] To solve the problems existing in the above technologies, for this reason, a highly twist-resistant and high-temperature-resistant cable for wind power generation is proposed. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a highly twist-resistant and high-temperature-resistant cable for wind power generation, which overcomes the deficiencies of the prior art and solves the problems mentioned in the above background art.

[0006] To achieve the above object, the present invention provides the following technical solution: A highly twist-resistant and high-temperature-resistant cable for wind power generation, comprising a multi-level anti-torsion conductor core, a dynamic compensation insulating layer, a three-dimensional braided shielding layer, a spiral heat dissipation channel layer and a sheath, which are arranged in sequence from inside to outside;

[0007] The multi-level anti-torsion conductor core adopts a tinned copper alloy conductor with a five-level stranding structure;

[0008] The dynamic compensation insulating layer adopts a ceramicized silicone rubber and a polyolefin nanocomposite material;

[0009] The spiral heat dissipation channel layer is composed of hollow metal wires spirally wound.

[0010] Through a five-level heterogeneous material stranding design, an internal stress cancellation effect is generated by using the difference in the elastic modulus of the materials. The ceramicized silicone rubber forms a porous ceramic skeleton at 300°C, and at the same time, the polyolefin melt fills the pores. After 200 thermal shock cycles, the insulation resistance retention rate > 95%. A Venturi effect is formed between the hollow metal wire layers, which can utilize the external wind to improve the heat dissipation efficiency.

[0011] As a preferred technical solution of the present invention, the five-level stranding structure includes:

[0012] The first level: 7 tinned copper-magnesium alloy wires with a diameter of 0.15 mm are stranded in the positive direction;

[0013] The second level: 12 first copper-nickel-silicon alloy wires with a diameter of 0.2 mm are stranded in the reverse direction;

[0014] The third level: 16 second copper-nickel-silicon alloy wires with a diameter of 0.18 mm are stranded in the positive direction;

[0015] The fourth level: 22 copper-magnesium alloy wires with a diameter of 0.15 mm are stranded in the reverse direction;

[0016] The fifth level: 25 tinned copper alloy wires with a diameter of 0.12 mm are stranded in the positive direction.

[0017] After each level of stranding, nano-silicone grease is coated to reduce the friction coefficient between layers, and the mechanical properties and conductivity are synergistically optimized through multi-level heterogeneous stranding.

[0018] As a preferred technical solution of the present invention, the stranding structures of the third to fifth levels adopt a geometric progression decreasing, the pitch ratio of the third level is 10 - 12 times, the pitch ratio of the fourth level is 8 - 10 times, and the pitch ratio of the third level is 6 - 8 times.

[0019] The third level: Bears the main mechanical load, the longer pitch (10 - 12 times) improves flexibility, and the copper-nickel-silicon alloy provides basic strength; The fourth level: The pitch is shortened to 8 - 10 times, and the copper-magnesium alloy offsets the residual stress of the third level through reverse stranding; The fifth level: Tightly stranded (6 - 8 times), the tinned copper layer fills the gaps to form a dense conductive surface.

[0020] As a preferred technical solution of the present invention, the polyolefin nanocomposite is maleic anhydride grafted polyolefin, and the dynamic compensation insulating layer adopts a mass ratio of 3:7 of ceramicized silicone rubber and polyolefin nanocomposite, and is formed by twin-screw co-extrusion.

[0021] The ceramicized silicone rubber forms a porous ceramic skeleton at 300 °C. At the same time, the polyolefin melt fills the pores, which can form a protective layer at high temperature while maintaining flexibility, and establish a gradient phase change protection mechanism for insulating materials.

[0022] As a preferred technical solution of the present invention, the three-dimensional braided shielding layer adopts a 45° cross-braided structure of semi-conductive nylon filaments and silver-plated copper wires.

[0023] The three-dimensional braided shielding layer adopts a double-layer design, braided with semi-conductive nylon and metal wires, taking into account flexibility and electromagnetic shielding.

[0024] As a preferred technical solution of the present invention, the hollow metal wire is filled with paraffin, and the phase change temperature is 80 - 120 °C.

[0025] The phase change material paraffin absorbs 15.8 J / g of latent heat at the temperature peak, reducing the temperature rise of the conductor. When the temperature > 80 °C, the volume expansion rate of the paraffin object is 18%, which promotes the acceleration of the airflow in the spiral channel formed by the hollow metal wires.

[0026] As a preferred technical solution of the present invention, the pitch of the inlet section of the hollow metal wire is 8 mm, the middle section is 6 mm, and the outlet section is 10 mm.

[0027] The airflow enters the continuously variable cross-section channel formed by adjacent hollow metal wires. When the flow area shrinks, the airflow velocity increases. The high-speed airflow is constrained by the spiral wall surface, generating a centrifugal force along the radial direction, forming a vortex, enhancing the heat exchange between the airflow and the hollow metal wires. The pitch of 8 mm in the inlet section can accelerate the airflow, 6 mm in the middle section can maintain the pressure difference, and 10 mm in the outlet section can prevent backflow.

[0028] As a preferred technical solution of the present invention, the sheath is composed of a polyurethane elastomer containing carbon nanotubes. Shallow grooves in the same direction as the helix are prefabricated on the inner surface of the sheath. Laser perforations with a diameter of 50 μm are provided on the outer layer of the sheath, and the perforation density is 200 - 300 holes / m 2 。

[0029] The sheath made of a polyurethane elastomer with carbon nanotubes can improve high-temperature resistance and environmental stress resistance. The external wind enters through the laser perforations (with a diameter of 50 μm) on the outer layer of the sheath. Since the aperture is smaller than the boundary layer thickness, a laminar jet is formed. The shallow grooves on the inner wall of the sheath guide the airflow to the starting end of the spiral channel, reducing the inlet turbulence loss. The airflow velocity increases when the airflow enters the continuously variable cross-section channel formed by adjacent hollow metal wires. The high-speed airflow is constrained by the spiral wall surface, generating a centrifugal force along the radial direction, enhancing the heat exchange between the airflow and the hollow metal wires. At the end of the spiral channel (outlet section), due to the pitch expanding to 10 mm, the flow cross-section increases and the velocity decreases, and the static pressure recovers to 92% of the ambient pressure. Dense laser perforations (with a density of 300 holes / m 2 , with an aperture of 80 μm) are provided on the leeward side (opposite to the wind direction) of the outer layer of the sheath, and unidirectional exhaust is achieved using the wind pressure difference.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1. Through the five-stage heterogeneous material stranding design, the internal stress cancellation effect is generated by using the difference in the elastic modulus of the materials. The ceramicized silicone rubber forms a porous ceramic skeleton at 300 °C, and at the same time, the polyolefin melt fills the pores. After 200 thermal shock cycles, the insulation resistance retention rate > 95%. The Venturi effect is formed between the layers of the hollow metal wires, which can improve the heat dissipation efficiency by using the external wind.

[0032] 2. The ceramized silicone rubber forms a porous ceramic skeleton at 300 °C. At the same time, the polyolefin melt fills the pores, which can form a protective layer at high temperatures while maintaining flexibility, and establish a gradient phase change protection mechanism for the insulating material.

[0033] 3. Utilize the external wind force to enter through the laser perforations (with a diameter of 50 μm) on the outer layer of the sheath. The shallow grooves on the inner wall of the sheath guide the air flow to the starting end of the spiral channel, reducing the inlet turbulence loss. As the air flow enters the continuously variable cross-section channel formed by adjacent hollow metal wires, the air flow velocity increases. The high-speed air flow is constrained by the spiral wall, generating a centrifugal force along the radial direction, enhancing the heat exchange between the air flow and the hollow metal wires, helping to dissipate heat, and preventing high-temperature accumulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the internal structure distribution of the present invention;

[0035] Figure 2 It is a schematic cross-sectional structure diagram of the present invention;

[0036] Figure 3 It is a schematic diagram of the hollow metal wire structure of the present invention;

[0037] Figure 4 It is a schematic diagram of the assembly of the hollow metal wire and the sheath of the present invention;

[0038] Figure 5 For the present invention Figure 4 Schematic side view;

[0039] Figure 6 For the present invention Figure 1 Partial enlarged schematic diagram at position A.

[0040] In the figure: 1. Tinned copper-magnesium alloy wire; 2. First copper-nickel-silicon alloy wire; 3. Second copper-nickel-silicon alloy wire; 4. Copper-magnesium alloy wire; 5. Tinned copper alloy wire; 6. Dynamic compensation insulating layer; 7. Three-dimensional braided shielding layer; 8. Hollow metal wire; 9. Laser perforation; 10. Sheath; 11. Shallow groove. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0042] Please refer to Figure 1-6, A highly torsion-resistant and high-temperature-resistant cable for wind power generation, comprising a multi-level anti-torsion conductor core, a dynamic compensation insulation layer 6, a three-dimensional braided shielding layer 7, a spiral heat dissipation channel layer, and a sheath 10 arranged in sequence from the inside to the outside;

[0043] The multi-level anti-torsion conductor core uses a tinned copper alloy conductor with a five-level stranded structure;

[0044] The dynamic compensation insulation layer 6 uses a ceramized silicone rubber and polyolefin nanocomposite material;

[0045] The spiral heat dissipation channel layer is composed of hollow metal wires 8 spirally wound. Through a five-level heterogeneous material stranded design, an internal stress cancellation effect is generated using the difference in the elastic modulus of the materials. The ceramized silicone rubber forms a porous ceramic skeleton at 300 °C, and at the same time, the polyolefin melt fills the pores to achieve "self-healing of damage". After 200 thermal shock cycles, the insulation resistance retention rate > 95%. A Venturi effect is formed between the layers of the hollow metal wires 8, which can utilize the external wind to improve the heat dissipation efficiency.

[0046] Specifically, the five-level stranded structure includes:

[0047] The first level: 7 tinned copper-magnesium alloy wires 1 with a diameter of 0.15 mm are stranded in the positive direction;

[0048] The second level: 12 first copper-nickel-silicon alloy wires 2 with a diameter of 0.2 mm are stranded in the reverse direction;

[0049] The third level: 16 second copper-nickel-silicon alloy wires 3 with a diameter of 0.18 mm are stranded in the positive direction;

[0050] The fourth level: 22 copper-magnesium alloy wires 4 with a diameter of 0.15 mm are stranded in the reverse direction;

[0051] The fifth level: 25 tinned copper alloy wires 5 with a diameter of 0.12 mm are stranded in the positive direction;

[0052] After each level of stranding, nano-silicone grease is coated to reduce the friction coefficient between layers, and the mechanical properties and conductivity are synergistically optimized through multi-level heterogeneous stranding.

[0053] Specifically, the stranding structures of the third to fifth levels adopt a geometric progression decrease. The pitch ratio of the third level is 10 - 12 times, the pitch ratio of the fourth level is 8 - 10 times, and the pitch ratio of the third level is 6 - 8 times. The third level: bears the main mechanical load, and the longer pitch (10 - 12 times) improves flexibility, and the copper-nickel-silicon alloy provides basic strength; The fourth level: the pitch is shortened to 8 - 10 times, and the copper-magnesium alloy cancels the residual stress of the third level through reverse stranding; The fifth level: tightly stranded (6 - 8 times), and the tinned copper layer fills the gaps to form a dense conductive surface.

[0054] Specifically, the polyolefin nanocomposite is maleic anhydride grafted polyolefin. The dynamic compensation insulating layer 6 is made of a ceramicized silicone rubber and the polyolefin nanocomposite with a mass ratio of 3:7, and is formed by twin-screw co-extrusion. The ceramicized silicone rubber forms a porous ceramic skeleton at 300 °C. At the same time, the polyolefin melt fills the pores, forming a protective layer at high temperature while maintaining flexibility, and establishing a gradient phase change protection mechanism for the insulating material.

[0055] Specifically, the three-dimensional braided shielding layer 7 adopts a cross-braided structure of semi-conductive nylon wires and silver-plated copper wires at 45°. The three-dimensional braided shielding layer 7 adopts a double-layer design, with semi-conductive nylon and metal wires braided, taking into account flexibility and electromagnetic shielding.

[0056] Specifically, the hollow metal wire 8 is filled with paraffin, with a phase change temperature of 80-120 °C. The phase change material paraffin absorbs 15.8 J / g of latent heat at the temperature peak, reducing the temperature rise of the conductor. When the temperature > 80 °C, the volume expansion rate of the paraffin object is 18%, promoting the acceleration of the airflow speed in the spiral channel formed by the hollow metal wire 8.

[0057] Specifically, the pitch of the inlet section of the hollow metal wire 8 is 8 mm, the middle section is 6 mm, and the outlet section is 10 mm. The airflow enters the continuously variable cross-section channel formed by adjacent hollow metal wires 8. When the flow area shrinks, the airflow speed increases. The high-speed airflow is constrained by the spiral wall surface, generating a centrifugal force along the radial direction, forming a vortex, enhancing the heat exchange between the airflow and the hollow metal wire 8. The pitch of 8 mm in the inlet section can accelerate the airflow, the 6 mm in the middle section can maintain the pressure difference, and the 10 mm in the outlet section can prevent backflow.

[0058] Specifically, the sheath 10 is composed of a polyurethane elastomer containing carbon nanotubes. The inner surface of the sheath 10 is prefabricated with shallow grooves 11 in the same direction as the helix. The outer layer of the sheath 10 is provided with laser perforations 9 with a diameter of 50 μm, and the perforation density is 200-300 holes / m 2 The sheath 10 made of a polyurethane elastomer with carbon nanotubes can improve high-temperature resistance and environmental stress resistance. The external wind enters through the laser perforations 9 (with a diameter of 50 μm) on the outer layer of the sheath 10. Since the aperture is smaller than the boundary layer thickness, a laminar jet is formed. The shallow grooves 11 on the inner wall of the sheath 10 guide the airflow to the starting end of the spiral channel, reducing the inlet turbulence loss. The airflow enters the continuously variable cross-section channel formed by adjacent hollow metal wires 8, and the airflow speed increases. The high-speed airflow is constrained by the spiral wall surface, generating a centrifugal force along the radial direction, enhancing the heat exchange between the airflow and the hollow metal wire 8. At the end (outlet section) of the spiral channel, due to the pitch expanding to 10 mm, the flow cross-section increases and the speed decreases, and the static pressure recovers to 92% of the ambient pressure. Dense laser perforations 9 (with a density of 300 holes / m 2 are provided on the leeward side (opposite to the wind direction) of the outer layer of the sheath 10, with an aperture of 80 μm, and one-way exhaust is achieved using the wind pressure difference.

[0059] Working principle: Through a five-stage heterogeneous material stranding design, the internal stress cancellation effect is generated by utilizing the difference in the elastic modulus of materials. The ceramized silicone rubber forms a porous ceramic skeleton at 300 °C, and at the same time, the polyolefin melt fills the pores. After 200 thermal shock cycles, the insulation resistance retention rate is > 95%. The Venturi effect is formed between the 8 layers of hollow metal wires, which can utilize the external wind to improve the heat dissipation efficiency.

[0060] Finally, it should be noted that in the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "vertical", "upper", "lower", "horizontal", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0061] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-twisting and high-temperature resistant cable for wind power generation, characterized in that: It comprises a multi-level torsion-resistant conductor core, a dynamic compensation insulation layer (6), a three-dimensional braided shielding layer (7), a spiral heat dissipation channel layer and a sheath (10) which are arranged in sequence from the inside to the outside; The multi-level torsion-resistant conductor core adopts a tinned copper alloy conductor with a five-level twisted structure; The dynamic compensation insulating layer (6) is made of ceramic silicone rubber and polyolefin nanocomposite material; The spiral heat dissipation channel layer is formed by spirally winding hollow metal wires (8).

2. A high-twisting-resistant and high-temperature-resistant wind power generation cable according to claim 1, characterized in that: The five-level twisted structure comprises: First stage: 7 0.15 mm diameter tinned copper-magnesium alloy wires (1) twisted in the positive direction; Second stage: 12 first copper-nickel-silicon alloy wires (2) with a diameter of 0.2 mm are twisted in opposite directions; The third stage: 16 second copper-nickel-silicon alloy wires (3) with a diameter of 0.18 mm are twisted in the positive direction; Level 4: 22 copper-magnesium alloy wires (4) with a diameter of 0.15 mm twisted in opposite directions; Fifth level: 25 0.12 mm diameter tinned copper alloy wires (5) twisted in the forward direction.

3. A high-twisting-resistant and high-temperature-resistant wind power cable according to claim 2, characterized in that: The third to fifth level twisted structures decrease in geometric progression, with the third level pitch ratio being 10-12 times, the fourth level pitch ratio being 8-10 times, and the third level pitch ratio being 6-8 times.

4. A high-twisting-resistant and high-temperature-resistant wind power generation cable according to claim 1, characterized in that: The polyolefin nanocomposite material is maleic anhydride grafted polyolefin, and the dynamic compensation insulating layer (6) is made of ceramic silicone rubber and polyolefin nanocomposite material in a mass ratio of 3:7, and is formed by twin-screw co-extrusion.

5. The high-twisting-resistant and high-temperature-resistant wind power cable according to claim 1, characterized in that: The three-dimensional braided shielding layer (7) adopts a 45° cross-braiding structure of semi-conductive nylon wires and silver-plated copper wires.

6. A high-twisting-resistant and high-temperature-resistant wind power cable according to claim 1, characterized in that: The hollow metal wire (8) is filled with paraffin wax, and the phase change temperature is 80-120°C.

7. A high-twisting-resistant and high-temperature-resistant wind power cable according to claim 1, characterized in that: The pitch of the hollow metal wire (8) is 8 mm at the inlet section, 6 mm in the middle section, and 10 mm at the outlet section.

8. The high-twisting-resistant and high-temperature-resistant wind power cable according to claim 1, characterized in that: The sheath (10) is made of polyurethane elastomer containing carbon nanotubes. The inner surface of the sheath (10) is prefabricated with shallow grooves (11) in the same direction as the spiral. The outer layer of the sheath (10) is provided with laser perforations (9) with a diameter of 50 μm, and the perforation density is 200-300 holes / m. 2 .

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