A wind turbine blade lightning cable and method of manufacturing the same

Abstract

The application discloses a wind power blade lightning protection cable and a manufacturing method thereof, and relates to the lightning protection technology field of wind power generation equipment. The wind power blade lightning protection cable comprises a central support, a plurality of conductor cores and a plurality of insulating layers. The central support is arranged at the axial center of the cable. The plurality of conductor cores are distributed along the circumference of the central support and are twisted outside the central support in a first twisting direction. Each conductor core is formed by twisting a plurality of copper conductor filaments in a second opposite twisting direction. Each insulating layer covers a corresponding conductor core. The inner surface of the insulating layer is provided with a spiral guide groove, which cooperates with the twisting lines on the outer surface of the conductor core. The wind power blade lightning protection cable can reduce the risk of conductor fatigue damage, insulating layer loosening and cracking during repeated bending and twisting, and improve the structural stability, fatigue resistance and long-term reliability of the cable.

Description

Technical Field

[0001] This invention relates to the field of lightning protection technology for wind power generation equipment, and in particular to a lightning protection cable for wind turbine blades and its manufacturing method. Background Technology

[0002] With the development of wind power generation technology, wind turbines are gradually becoming larger, with increased blade length and flexibility. Wind turbine blades are typically equipped with lightning protection systems to guide the lightning current received by the lightning arrester to the grounding terminal, reducing the damage caused by lightning strikes to the blades and wind turbines. Lightning protection cables, as current-conducting components in the lightning protection system of wind turbine blades, usually extend along the inside of the blade. During blade operation, continuous oscillation and deformation subject the lightning protection cables to repeated bending and torsional loads over long periods, placing high demands on the structural stability of the cables.

[0003] Under repeated bending and twisting conditions of long and flexible blades, existing lightning protection cables are prone to uneven stress inside the cable core, causing local stress concentration and fatigue damage to the conductor, which affects the long-term reliability of the lightning protection cable. Summary of the Invention

[0004] The purpose of this invention is to provide a lightning protection cable for wind turbine blades and its manufacturing method, in order to solve the technical problem that existing lightning protection cables are prone to uneven stress inside the cable core under repeated bending and torsion conditions of long and flexible blades, which causes local stress concentration and fatigue damage to the conductor and affects the long-term reliability of the lightning protection cable.

[0005] To achieve the above objectives, the present invention provides a wind turbine blade lightning protection cable, comprising a central support member, multiple conductor cores, and multiple insulation layers; the central support member is disposed at the axial center of the wind turbine blade lightning protection cable, the multiple conductor cores are distributed circumferentially along the central support member and are stranded on the outside of the central support member in a first stranding direction; each conductor core is formed by stranding multiple copper conductor wires in a second stranding direction, the first stranding direction being opposite to the second stranding direction; the multiple insulation layers correspond one-to-one with the multiple conductor cores, each insulation layer covering the outside of the corresponding conductor core, and the inner surface of each insulation layer is provided with a spiral guide groove extending spirally along the axial direction of the corresponding conductor core, the spiral guide groove cooperating with the stranding pattern on the outer surface of the corresponding conductor core.

[0006] Preferably, the central support member is a solid structure and is made of elastic polypropylene material.

[0007] Preferably, the conductor core is provided with five strands, and the five strands of the conductor core are evenly distributed along the circumference of the central support member.

[0008] Preferably, the copper conductor wire is a circular tin-plated copper conductor wire, and the multiple copper conductor wires in each conductor core are divided into a first layer, a second layer, a third layer and a fourth layer from the inside out. The first layer includes one copper conductor wire located at the center of the conductor core, the second layer includes six copper conductor wires, the third layer includes twelve copper conductor wires, and the fourth layer includes twelve copper conductor wires.

[0009] Preferably, the pitch of the spiral guide groove matches the stranding pitch of the corresponding conductor core, the helix angle of the spiral guide groove is consistent with the stranding helix angle of the corresponding conductor core, and the bottom cross-section of the spiral guide groove is circular or trapezoidal.

[0010] Preferably, the device further includes a filler layer disposed between and outside the plurality of insulating layers, the filler layer being made of polypropylene elastomer in which conductive filler is dispersed.

[0011] Preferably, the conductive filler is a conductive microfiber or a conductive nanofiller; the conductive microfiber is one of carbon fiber microfiber or nickel-plated carbon fiber microfiber, and the conductive nanofiller is one or more of carbon nanotubes, graphene nanosheets, conductive carbon black, or carbon nanofibers.

[0012] Preferably, it further includes a wrapping layer and an outer sheath layer. The wrapping layer includes multiple layers of polyester fiber tape, which are spirally wrapped around the outside of multiple insulating layers and filling layers, with the wrapping directions of adjacent layers of polyester fiber tape being opposite. The outer sheath layer covers the outside of the wrapping layer and is made of silicone rubber.

[0013] Accordingly, the technical solution of the present invention also provides a method for manufacturing a lightning protection cable for wind turbine blades, comprising: stranding multiple sets of copper conductor monofilaments in a second stranding direction to form multiple conductor cores; covering the outer side of each conductor core with an insulation layer, wherein the inner surface of the insulation layer is provided with a spiral guide groove extending in a spiral shape along the axial direction of the corresponding conductor core, and the spiral guide groove is matched with the stranding pattern on the outer surface of the corresponding conductor core; arranging the multiple conductor cores covered with the insulation layer at circumferential intervals along a central support member, and stranding them on the outer side of the central support member in a first stranding direction, wherein the first stranding direction is opposite to the second stranding direction.

[0014] Preferably, after the multiple strands of the conductor core are twisted together on the outside of the central support, a polypropylene elastomer with conductive filler dispersed inside is filled between the multiple insulating layers and on the outside of the multiple insulating layers to form a filling layer; multiple layers of polyester fiber tape are spirally wrapped in layers on the outside of the multiple insulating layers and the filling layer to form a wrapping layer, and the wrapping directions of adjacent two layers of polyester fiber tape are opposite; silicone rubber is covered on the outside of the wrapping layer to form an outer sheath layer.

[0015] Compared to the aforementioned background technology, the wind turbine blade lightning protection cable provided by this invention has the following beneficial effects: In this invention, each conductor core is formed by stranding multiple copper conductor wires in a second stranding direction. Each conductor core is then stranded on the outside of the central support member in a first stranding direction opposite to the second stranding direction. This creates a reverse twisting relationship between the internal stranding structure of the conductor core and the overall stranding structure of the multi-strand conductor core, which helps reduce axial cumulative deformation during cable torsion and lowers the risk of conductor structure loosening and fatigue damage to the copper conductor wires. Furthermore, an insulation layer is provided on the outside of each conductor core, and the spiral guide groove on the inner surface of the insulation layer matches the stranding pattern on the outer surface of the conductor core. This restricts circumferential relative slippage between the insulation layer and the conductor core, reducing the risk of the insulation layer loosening or wrinkling during repeated torsion. Through the interaction of the central support member, the reverse twisting structure, and the spiral fit between the insulation layer and the conductor core, the structural stability and fatigue resistance of the wind turbine blade lightning protection cable under long-term repeated bending and torsional loads can be improved, enhancing the long-term reliability of the lightning protection cable. The lightning protection cable for wind turbine blades manufactured using the manufacturing method provided by this invention has the aforementioned beneficial effects. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the cross-sectional structure of the lightning protection cable for wind turbine blades provided in an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached drawings: 1-Central support; 2-Conductor core; 3-Filling layer; 4-Wrapping layer; 5-Outer sheath layer; 6-Insulation layer; 7-Spiral guide groove. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1 As shown, this invention provides a wind turbine blade lightning protection cable, including a central support 1, multiple conductor cores 2, and multiple insulation layers 6. The central support 1 is located at the axial center of the wind turbine blade lightning protection cable. The multiple conductor cores 2 are distributed circumferentially along the central support 1 and are stranded on the outside of the central support 1 in a first stranding direction. Each conductor core 2 is formed by stranding multiple copper conductor wires in a second stranding direction, with the first stranding direction being opposite to the second stranding direction. The multiple insulation layers 6 correspond one-to-one with the multiple conductor cores 2, and each insulation layer 6 covers the outside of the corresponding conductor core 2. The inner surface of the insulation layer 6 is provided with a spiral guide groove 7 extending spirally along the axial direction of the corresponding conductor core 2, and the spiral guide groove 7 cooperates with the stranding pattern on the outer surface of the corresponding conductor core 2. Specifically, the central support 1 is located in the central region of the wind turbine blade lightning protection cable, and the multiple conductor cores 2 are arranged around the central support 1. The central support 1 is used to support the outer conductor cores 2 and maintain the stability of the cable core cross-section. The conductor core 2 adopts a flexible structure of multiple copper conductor wires twisted together. The overall twisting direction of the multi-strand conductor core 2 is opposite to the twisting direction of the copper conductor wires inside the single-strand conductor core 2, so that the internal twisting structure of the conductor core and the overall twisting structure of the multi-strand conductor core form a reverse twisting relationship. The insulation layer 6 covers each conductor core 2. The insulation layer 6 is made of ethylene propylene rubber with a wall thickness of 1mm-2mm. The spiral guide groove 7 on the inner surface of the insulation layer 6 extends continuously along the axial direction of the conductor core 2 and matches the twisting pattern on the surface of the conductor core 2. The central support 1 can provide support for the outer conductor core 2, reducing the mutual compression and local stress concentration between the conductor cores 2 during repeated bending and twisting of the cable. Moreover, the reverse twisting relationship helps to reduce the axial cumulative deformation generated during twisting, reducing the risk of conductor structure loosening and copper conductor wire fatigue damage; the cooperation between the spiral guide groove 7 and the twisting pattern can limit the circumferential relative slippage between the insulation layer 6 and the conductor core 2, reducing the risk of the insulation layer 6 loosening or wrinkling during repeated twisting. In addition, the combination of the central support, the reverse twisted structure, and the spiral fit between the insulation layer and the conductor core helps to improve the structural stability and fatigue resistance of the wind turbine blade lightning protection cable under long-term repeated bending and torsional loads, and improves its long-term reliability.

[0022] In some embodiments of the present invention, the central support 1 is a solid structure and is made of elastic polypropylene material. Specifically, the central support 1 is made of elastic PP polypropylene, and the solid structure can form a stable support at the center of the cable core. When the wind turbine blades swing and cause the cable to bend or twist, the elastic polypropylene material can produce adaptive elastic deformation, while maintaining the support function of the central area. This prevents the outer conductor cores 2 from being excessively squeezed towards the central area, which helps to maintain a more uniform stress state for each conductor core 2 and reduces friction and compression wear between adjacent conductor cores 2.

[0023] In this embodiment, the conductor core 2 has five strands, which are evenly distributed around the circumference of the central support member 1. Specifically, the five conductor cores 2 form a circumferentially uniform arrangement around the central support member 1, which makes the conductor distribution around the central support member 1 more balanced. In this embodiment, the total cross-sectional area of ​​the five conductor cores 2 is not less than 70 mm², which forms a large lightning current conduction cross section while maintaining a multi-strand flexible structure, so as to meet the high current conduction requirements of the wind turbine blade lightning protection system.

[0024] It should be noted that the copper conductor wires are round, tin-plated copper conductor wires. Each conductor core 2 consists of multiple copper conductor wires arranged from the inside out as a first layer, a second layer, a third layer, and a fourth layer. The first layer includes one copper conductor wire at the center of the conductor core 2; the second layer includes six copper conductor wires; the third layer includes twelve copper conductor wires; and the fourth layer includes twelve copper conductor wires. Specifically, each conductor core 2 comprises 31 round, tin-plated copper conductor wires with a diameter of 0.8 mm. These 31 copper conductor wires are arranged in four layers: one copper conductor wire at the center, six wires around the center in the second layer, twelve wires in the third layer, and twelve wires in the fourth layer. All layers of copper conductor wires are twisted together in the second twisting direction to form a single conductor core 2. The 0.8 mm wire diameter improves the flexibility of the conductor core 2. Combined with the total conductor cross-sectional area of ​​not less than 70 mm² formed by multiple conductor cores 2, it balances bending adaptability and large cross-sectional current carrying capacity, and helps reduce the DC resistance of the conductor.

[0025] Furthermore, each conductor core 2 is covered by an insulation layer 6 and isolated from each other. This dispersed conductor structure, formed by multiple conductor cores 2 and fine-diameter copper conductor filaments, helps improve the current distribution when higher frequency components of the lightning current pass through, reducing the risk of local current concentration and local temperature rise. Each conductor core 2 is formed by twisting multiple small-diameter copper conductor filaments together. The multiple conductor cores 2 are dispersed circumferentially along the central support 1 and are each covered by a corresponding insulation layer 6. Compared to using a single large-section solid conductor, the aforementioned multi-strand, multi-filament conductor structure can improve the conductor's flexibility while ensuring the required total conductor cross-sectional area, and relatively disperse the conductive path within the cross-sectional area of ​​the wind turbine blade lightning protection cable. When the lightning current contains higher frequency components, the current distribution in the conductor may be affected by factors such as the skin effect. The dispersed conductor structure formed by multiple conductor cores 2 and multiple copper conductor filaments can provide multiple parallel conductive regions for the current, which helps improve the current distribution within the conductor cross-section, reduces the possibility of excessive current concentration in local areas, and thus helps reduce local temperature rise. It should be noted that the degree of improvement in current distribution by the above structure is related to factors such as the frequency components of the lightning current, the size and arrangement of the conductor core 2. This embodiment mainly uses multi-strand conductor core 2 and thin-diameter copper conductor single wire to meet the requirements of lightning current conduction while taking into account the bending adaptability of the cable.

[0026] In some embodiments of the present invention, the pitch of the spiral guide groove 7 matches the stranding pitch of the corresponding conductor core 2, the helix angle of the spiral guide groove 7 is consistent with the stranding helix angle of the corresponding conductor core 2, and the bottom cross-section of the spiral guide groove 7 is arc-shaped or trapezoidal. Specifically, the spiral guide groove 7 is disposed on the side of the insulating layer 6 that is in contact with the conductor core 2, its pitch corresponds to the stranding pitch of the conductor core 2, and its helix angle is consistent with the stranding helix angle of the conductor core 2, so that the spiral guide groove 7 extends along the stranding pattern on the surface of the conductor core 2. The wall thickness of the insulating layer 6 is 1mm-2mm, the groove depth of the spiral guide groove 7 is 20% of the total wall thickness of the insulating layer 6, the groove width is 0.6-1.0mm, and the bottom cross-section of the groove is arc-shaped or trapezoidal. When the spiral guide groove 7 is combined with the stranded pattern, it can limit the relative slippage between the insulation layer 6 and the conductor core 2 in the circumferential direction, reducing the possibility of the insulation layer 6 loosening or wrinkling during repeated torsion; the spiral guide groove 7 can also form a continuous bending stress release area, reducing the risk of local cracking of the inner wall of the insulation layer 6 due to repeated bending.

[0027] In some embodiments, a filler layer 3 is further included, which is disposed between and on the outer side of the plurality of insulating layers 6. The filler layer 3 is made of polypropylene elastomer, and conductive filler is dispersed within the polypropylene elastomer. Specifically, the filler layer 3 fills the gaps between the insulating layers 6 and surrounds the outer side of the plurality of insulating layers 6, making the outer contour of the cable core more rounded, while providing flexible support for adjacent insulating layers 6 and the conductor core 2 inside them. The polypropylene elastomer is specifically a low-smoke flame-retardant PP polypropylene elastomer, which, while maintaining the low-smoke flame-retardant properties and mechanical properties of the substrate, imparts appropriate conductivity to the filler layer 3 by dispersing conductive filler therein.

[0028] In some embodiments of the present invention, the conductive filler is a conductive microfiber or a conductive nanofiller; the conductive microfiber is one of carbon fiber microfiber or nickel-plated carbon fiber microfiber, and the conductive nanofiller is one or more of carbon nanotubes, graphene nanosheets, conductive carbon black, or carbon nanofibers. Specifically, when the conductive filler is a conductive microfiber, the conductive microfiber is specifically a carbon fiber microfiber or a nickel-plated carbon fiber microfiber, and the conductive microfiber accounts for 1%-2% of the mass fraction of the filler layer; when the conductive filler is a conductive nanofiller, the conductive nanofiller can be one or more of carbon nanotubes, graphene nanosheets, conductive carbon black, or carbon nanofibers. The conductive filler is dispersed in the polypropylene elastomer to form a conductive path, thereby controlling the volume resistivity of the filler layer 3 at 10 Ω·cm. 6 -10 9 Within the Ω·cm range, this allows the filling layer 3 to have moderate conductivity.

[0029] Furthermore, the conductive filler is dispersed in the polypropylene elastomer. Multiple conductive filler particles or fibers can form dispersed conductive paths through mutual contact or close proximity, giving the filler layer 3 a certain charge conduction capability. Since the filler layer 3 is continuously arranged along the length of the wind turbine blade lightning protection cable, the conductive filler dispersed in the filler layer 3 can form charge transfer paths distributed along the cable length within the filler layer 3. When the cable generates local static charge during bending, twisting, and contact with surrounding structures, the static charge can migrate and diffuse within the filler layer 3 through the conductive paths formed between adjacent conductive fillers. This helps reduce the concentration of static charge in local areas of the filler layer 3 and improves the potential balance between different areas of the filler layer 3. It should be noted that the conductive filler in the filler layer 3 mainly improves the electrostatic dissipation performance of the filler layer 3 itself and does not replace the lightning current conduction function undertaken by the conductor core 2. The conductor core 2 constitutes the main lightning current transmission path of the wind turbine blade lightning protection cable, while the filler layer 3, while maintaining flexible support and filling for the insulation layer 6 and conductor core 2, also helps reduce the risk of localized electrostatic accumulation within the cable.

[0030] In this embodiment, the system also includes a wrapping layer 4 and an outer sheath layer 5. The wrapping layer 4 comprises multiple layers of polyester fiber tape, which are spirally wrapped around the outside of multiple insulation layers 6 and filling layers 3, with adjacent layers of polyester fiber tape having opposite wrapping directions. The outer sheath layer 5 covers the outside of the wrapping layer 4 and is made of silicone rubber. Specifically, the polyester fiber tape is made of PET polyester nonwoven fabric. The wrapping layer 4 consists of 2-3 layers of PET polyester nonwoven fabric tape, with each layer spirally wrapped at a wrapping angle of 30°-60°. Adjacent layers of tape have opposite spiral directions; when one layer is an S-axis spiral, the adjacent layer is a Z-axis spiral, forming an SZ alternating arrangement. The opposite direction of the tape can provide stress compensation, reduce axial cumulative expansion and contraction under torsional loads, and tighten the cable core. The outer sheath layer 5 uses VMQ silicone rubber, with a Shore hardness of A30-A50 and an operating temperature range of -60℃ to +200℃. This allows it to withstand repeated bending and torsional loads inside the wind turbine blade, reducing the risk of fatigue cracks or permanent deformation in the outer sheath layer 5. The spiral pattern formed by the wrapping layer 4 coordinates with the twisted pattern of the inner conductor core 2, which helps reduce interlayer interference and wear.

[0031] Combination Figure 1 The present invention also provides a method for manufacturing a wind turbine blade lightning protection cable, in addition to the structure of the wind turbine blade lightning protection cable shown. In this embodiment, the manufacturing method includes: stranding multiple sets of copper conductor wires in a second stranding direction to form multiple conductor cores 2; covering each conductor core 2 with an insulation layer 6, the inner surface of the insulation layer 6 having a spiral guide groove 7 extending spirally along the axial direction of the corresponding conductor core 2, and the spiral guide groove 7 matching the stranding pattern on the outer surface of the corresponding conductor core 2; arranging the multiple conductor cores 2 covered with the insulation layer 6 at circumferential intervals along the central support member 1, and stranding them on the outside of the central support member 1 in a first stranding direction, the first stranding direction being opposite to the second stranding direction. Specifically, during manufacturing, multiple sets of copper conductor wires are first stranded in the second stranding direction to form each conductor core 2; in this embodiment, each conductor core 2 uses 31 circular tin-plated copper conductor wires with a diameter of 0.8 mm, stranded in a four-layer arrangement. Subsequently, an ethylene propylene rubber (EPR) insulation layer 6 is wrapped around the outside of each conductor core 2, and the spiral guide groove 7 on the inner surface of the insulation layer 6 extends along the stranding pattern on the surface of the conductor core 2. The pitch of the spiral guide groove 7 matches the stranding pitch, and the helix angle matches the stranding helix angle, so that the two are matched. Then, the multiple conductor cores 2 wrapped with the insulation layer 6 are arranged circumferentially around the central support member 1 at intervals, and re-stranded in the first stranding direction opposite to the second stranding direction. In specific implementation, five conductor cores 2 can be evenly distributed circumferentially along the central support member 1, and the central support member 1 is made of solid elastic polypropylene material.

[0032] In some embodiments of the present invention, after the multi-strand conductor core 2 is twisted to the outside of the central support member 1, a polypropylene elastomer with conductive filler dispersed inside is filled between and on the outside of the multiple insulating layers 6 to form a filling layer 3; multiple layers of polyester fiber wrapping tape are spirally wrapped in layers on the outside of the multiple insulating layers 6 and the filling layer 3 to form a wrapping layer 4, and the wrapping directions of adjacent two layers of polyester fiber wrapping tape are opposite; silicone rubber is covered on the outside of the wrapping layer 4 to form an outer sheath layer 5. Specifically, after the multi-strand conductor core 2 is twisted around the central support 1, low-smoke flame-retardant PP polypropylene elastomer with internally dispersed conductive filler is filled into the gaps between multiple insulating layers 6 and the outer regions of multiple insulating layers 6 to form a filling layer 3. Subsequently, 2-3 layers of PET polyester nonwoven fabric are spirally wrapped around the outer sides of the insulating layers 6 and the filling layer 3, with each layer having a wrapping angle of 30°-60° and the wrapping directions of adjacent layers being opposite to form an SZ alternating wrapping structure. Finally, VMQ silicone rubber is coated on the outer side of the wrapping layer 4 to form an outer sheath layer 5, with a Shore hardness of A30-A50. When conductive microfibers are used as conductive fillers, their mass fraction is preferably 1%-2%; when conductive nanofillers are used, one or more of carbon nanotubes, graphene nanosheets, conductive carbon black, or carbon nanofibers can be selected.

[0033] The working principle of this invention is as follows: When the wind turbine blade is running, the lightning protection cable repeatedly bends and twists with the blade's sway. The central support member 1 provides support for the outer conductor core 2 at the center of the cable core, reducing the collapse of the central area of ​​the cable core and the mutual compression of the conductor cores 2. The twisting direction of the copper conductor single wires inside the conductor core 2 is opposite to the twisting direction of the multiple conductor cores 2 around the central support member 1, so that the two-stage twisting structure forms a reverse twisting relationship, reducing the axial cumulative deformation caused by torsion. The spiral guide groove 7 on the inner surface of the insulation layer 6 cooperates with the twisting pattern on the surface of the conductor core 2 to form a circumferential limit for the insulation layer 6. The conductive filler in the filling layer 3 gives the filling layer 3 appropriate conductivity. The wrapping layer 4 forms stress compensation through the reverse wrapping of adjacent wrapping tapes. The outer sheath layer 5 provides external protection for the inner cable core, enabling the wind turbine blade lightning protection cable to adapt to long-term dynamic operating conditions.

[0034] In summary, this invention, through the coordinated structure of central support, reverse twisting, spiral fit, conductive filling, reverse wrapping, and flexible outer sheath, improves the stability and fatigue resistance of the cable core structure while ensuring lightning current conduction and long-term reliability.

[0035] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0036] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A lightning protection cable for wind turbine blades, characterized in that, It includes a central support (1), a multi-strand conductor core (2), and multiple insulating layers (6); The central support member (1) is located at the axial center of the wind turbine blade lightning protection cable. Multiple conductor cores (2) are distributed circumferentially along the central support member (1) and twisted together on the outside of the central support member (1) in the first twisting direction. Each conductor core (2) is formed by twisting multiple copper conductor monofilaments together in a second twisting direction, wherein the first twisting direction is opposite to the second twisting direction; Multiple insulating layers (6) correspond one-to-one with multiple conductor cores (2). Each insulating layer (6) covers the outer side of the corresponding conductor core (2). The inner surface of the insulating layer (6) is provided with a spiral guide groove (7) extending spirally along the axial direction of the corresponding conductor core (2). The spiral guide groove (7) matches the twisted pattern on the outer surface of the corresponding conductor core (2).

2. The lightning protection cable for wind turbine blades according to claim 1, characterized in that, The central support (1) is a solid structure and is made of elastic polypropylene material.

3. The wind turbine blade lightning protection cable according to claim 1, characterized in that, The conductor core (2) is provided with five strands, and the five strands of the conductor core (2) are evenly distributed along the circumference of the central support member (1).

4. The wind turbine blade lightning protection cable according to claim 1, characterized in that, The copper conductor wire is a round tin-plated copper conductor wire. Each conductor core (2) has multiple copper conductor wires divided into a first layer, a second layer, a third layer and a fourth layer from the inside out. The first layer includes one copper conductor wire located in the center of the conductor core (2), the second layer includes six copper conductor wires, the third layer includes twelve copper conductor wires, and the fourth layer includes twelve copper conductor wires.

5. The wind turbine blade lightning protection cable according to claim 1, characterized in that, The pitch of the spiral guide groove (7) matches the stranding pitch of the corresponding conductor core (2), the helix angle of the spiral guide groove (7) is consistent with the stranding helix angle of the corresponding conductor core (2), and the bottom cross section of the spiral guide groove (7) is circular or trapezoidal.

6. The wind turbine blade lightning protection cable according to claim 1, characterized in that, It also includes a filler layer (3) disposed between and outside the plurality of insulating layers (6), the filler layer (3) being made of polypropylene elastomer, wherein conductive filler is dispersed within the polypropylene elastomer.

7. The wind turbine blade lightning protection cable according to claim 6, characterized in that, The conductive filler is a conductive microfiber or a conductive nanofiller; the conductive microfiber is one of carbon fiber microfiber or nickel-plated carbon fiber microfiber, and the conductive nanofiller is one or more of carbon nanotubes, graphene nanosheets, conductive carbon black or carbon nanofibers.

8. The wind turbine blade lightning protection cable according to claim 6, characterized in that, It also includes a wrapping layer (4) and an outer sheath layer (5). The wrapping layer (4) includes multiple layers of polyester fiber wrapping tape, which are spirally wrapped around the outside of multiple insulating layers (6) and filling layers (3) in layers, and the wrapping directions of adjacent layers of polyester fiber wrapping tape are opposite. The outer sheath layer (5) covers the outside of the wrapping layer (4) and is made of silicone rubber.

9. A method for manufacturing a lightning protection cable for wind turbine blades, characterized in that, include: Multiple sets of copper conductor single wires are twisted together in the second twisting direction to form a multi-strand conductor core (2). An insulating layer (6) is wrapped around the outside of each conductor core (2). The inner surface of the insulating layer (6) is provided with a spiral guide groove (7) extending in a spiral shape along the axial direction of the corresponding conductor core (2), and the spiral guide groove (7) is matched with the twisted pattern on the outer surface of the corresponding conductor core (2). The conductor cores (2) covered with the insulating layer (6) are arranged at circumferential intervals along the central support member (1) and twisted on the outside of the central support member (1) in a first twisting direction, which is opposite to the second twisting direction.

10. The method for manufacturing a lightning protection cable for wind turbine blades according to claim 9, characterized in that, After the multiple conductor cores (2) are twisted together on the outside of the central support (1), a polypropylene elastomer with conductive filler dispersed inside is filled between the multiple insulating layers (6) and on the outside of the multiple insulating layers (6) to form a filling layer (3); a multilayer polyester fiber wrapping tape is spirally wrapped in layers on the outside of the multiple insulating layers (6) and the filling layer (3) to form a wrapping layer (4), and the wrapping directions of two adjacent layers of polyester fiber wrapping tape are opposite; silicone rubber is covered on the outside of the wrapping layer (4) to form an outer sheath layer (5).

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