Metal net series downlead lightning protection system based on gradual change technology

Abstract

The invention discloses a metal net series connection downlead lightning protection system based on a gradual change technology, relates to the technical field of wind turbine blade design, is applied to wind turbine blades, and comprises a series connection metal net system comprising a main metal net, a blade root metal net grounding piece, a blade tip metal net grounding piece and a downlead assembly, the down lead assembly and the metal net system are connected in series; the lightning receiving system is arranged on the surface of the blade; the mass per unit area of the metal net system is distributed in a gradient mode in the spanwise direction of the blade, a low-gram-weight area, a transition area and a high-gram-weight area are formed, the high-gram-weight area covers a blade tip area, and the cost is greatly reduced while the thunder and lightning conduction performance is basically not changed. Meanwhile, metal nets with different gram weight specifications are integrally formed through the metal net gradual change technology, the breadth of the metal nets in the blade tip area is reduced through the large gram weight metal nets, and the problem that the metal nets in the blade tip area cannot conduct protection and the differential protection problem of different thunder and lightning zones of the blade are solved.

Description

Technical Field

[0001] The invention relates to the technical field of wind turbine blade design, in particular to a metal mesh series downconductor lightning protection system based on gradient technology. Background Art

[0002] Conventional lightning protection systems for carbon fiber blades consist of a dual-circuit system consisting of a downconductor and a metal mesh in parallel. Research results show that this dual-circuit downconductor lightning protection system conducts less than 20% of the lightning current, leading to redundant design and excessive costs.

[0003] Patent publication number CN116917618A, "Lightning Protection System," provides a downconductor lightning protection system for carbon fiber blades. While this patent uses metal mesh or metal foil as the central downconductor lightning current conductor within the system, it only provides a lightning protection solution for carbon fiber blades. Furthermore, this patent fails to achieve metal mesh coverage within a 5-meter radius of the blade tip. This issue has become a pressing issue for researchers in this field. Summary of the Invention

[0004] The object of the present invention is to provide a metal mesh series down conductor lightning protection system based on gradient technology to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution: a metal mesh series downconductor lightning protection system based on gradient technology, applied to wind turbine blades, comprising: A metal mesh system connected in series and laid along the span direction of the blade, the metal mesh system comprising a main metal mesh, a blade root metal mesh grounding piece, and a blade tip metal mesh grounding piece; a down conductor assembly, the down conductor assembly being connected in series with the metal mesh system; The lightning termination system includes a blade body lightning termination and a blade tip lightning termination and is arranged on the blade surface; The mass per unit area of ​​the main metal mesh is distributed in a gradient along the span direction of the blade, forming a low-gram weight area, a transition area and a high-gram weight area, wherein the high-gram weight area covers the tip area of ​​the blade, and the mass per unit area of ​​the metal mesh system is distributed in a gradient along the span direction of the blade, including at least one group of transition areas.

[0006] According to the above technical solution, the metal mesh series down conductor system is distributed on at least one surface of the blade. The metal mesh series down conductor system distributed on two surfaces is connected by overlapping metal sheets in a conductive stitching structure to form a continuous conductive path.

[0007] According to the above technical solution, the low grammage area is arranged from the blade root to the blade middle section, the transition zone is arranged in the blade middle section, and the high grammage area is arranged in the blade tip section.

[0008] According to the above technical solution, the high-weight area extends to cover the range of 5m from the blade tip and is directly connected to the blade tip lightning receptor or the blade body lightning receptor through a metal sheet or a conductive adhesive layer.

[0009] According to the above technical solution, the mass per unit area of ​​the metal mesh system is distributed in a gradient along the span direction of the wind turbine blade.

[0010] According to the above technical solution, the high-weight area extends to cover the blade tip and is directly connected to the blade tip lightning receptor or the blade body lightning receptor via a metal sheet or a conductive adhesive layer.

[0011] According to the above technical solution, one end of the tip down conductor is connected to the blade tip lightning rod and the blade body lightning rod arranged at the tip of the wind turbine blade, and the other end of the tip down conductor includes a grounding base - a high-weight area connected in series to the metal mesh system.

[0012] According to the above technical solution, one end of the root down conductor is connected to the low-weight area of ​​the metal mesh system, and the other end of the root down conductor includes a grounding base 2 connected to the blade root grounding piece.

[0013] According to the above technical solution, a first metal mesh grounding piece is provided on the first main metal mesh, and a second metal mesh grounding piece is provided on the second main metal mesh.

[0014] According to the above technical solution, the metal mesh system is connected to the grounding base 1 and the grounding base 2 through the metal mesh grounding piece 1 and the metal mesh grounding piece 2 to form a single-loop lightning current conduction path.

[0015] Compared with existing technologies, the present invention achieves the following beneficial effects: it is applicable not only to carbon fiber blades, but also to glass fiber blades for lightning protection. Compared with a dual-circuit system with parallel metal mesh, it substantially reduces costs while maintaining lightning conductivity. Furthermore, it utilizes metal mesh gradient technology to achieve the integrated molding of metal meshes of varying weights. Using high-weight metal mesh reduces the width of the metal mesh in the blade tip area, addressing the problem of metal mesh failure in the blade tip area and the differentiated protection of different lightning zones on the blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 This is a connection principle diagram of the metal mesh series down conductor lightning protection system based on the gradient technology of the present invention (single shell); Figure 2This is a layout diagram of wind turbine blades in a metal mesh series down conductor lightning protection system based on gradient technology of the present invention; Figure 3 This is a schematic diagram showing the connection principle of the metal mesh series down conductor lightning protection system in the blade thickness direction based on the gradient technology of the present invention; Figure 4 This is a schematic diagram of the connection between the metal mesh system and the tip down conductor system of the present invention; Figure 5 This is the low-weight and high-weight distribution diagram of the metal mesh series down conductor lightning protection system based on the gradient technology of the present invention (single shell); Figure 6 It is a schematic diagram of the gradient technology of the main metal mesh of the present invention; Figure 7 Schematic diagram of the arrangement of the tip down conductor system of the present invention (single housing); Figure 8 It is a schematic diagram of the gradual change structure of the metal mesh of the present invention.

[0017] In the figure: 1. Wind turbine blade; 2. Root grounding piece; 3. Root down conductor; 4. Blade root grounding metal mesh 1; 5. Main metal mesh 1; 6. Main metal mesh 2; 7. Grounding base 2; 8. Blade body lightning rod; 9. Tip down conductor; 10. Blade tip lightning rod; 11. Metal mesh grounding piece 1; 12. Metal mesh grounding piece 2; 13. Metal sheet; 14. Grounding base 1; 15. Grounding metal mesh 1; 16. Grounding metal mesh 2; 17. Main metal mesh; 18. Lightning termination system module; 19. Blade shell 1; 20. Blade shell 2; 21. Metal mesh system; 22. Low-weight area; 23. Transition zone; 24. High-weight area; 25. Blade root metal mesh grounding piece 2; 26. Blade tip metal mesh grounding piece 2; 27. Blade tip metal mesh grounding piece 1. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] See also Figure 1-8 The present invention provides a technical solution: a metal mesh series down conductor lightning protection system based on gradient technology, comprising a wind turbine blade 1, wherein the wind turbine blade 1 is provided with a metal mesh series down conductor system, comprising: A metal mesh system 21 is laid along the span direction of the wind turbine blade 1 and is arranged in series. The metal mesh system 21 includes a main metal mesh 17, a blade root metal mesh grounding piece, and a blade tip metal mesh grounding piece. The down conductor assembly includes a root down conductor 3 and a tip down conductor 9, and the down conductor assembly is connected in series with the metal mesh system 21; The lightning termination system includes a blade body lightning termination device 8 and a blade tip lightning termination device 10. The blade body lightning termination device 8 and the blade tip lightning termination device 10 are arranged on the surface of the wind turbine blade 1; The mass per unit area of ​​the main metal mesh 17 is distributed in a gradient along the span direction of the blade, forming a low-grammage area 22, a transition area 23 and a high-grammage area 24, wherein the high-grammage area 24 covers the tip area, and the mass per unit area of ​​the metal mesh system 21 is distributed in a gradient along the span direction of the wind turbine blade 1, including at least one group of transition areas 23.

[0020] refer to Figure 3 and Figure 4 The metal mesh system 21 extends from the blade root to the blade tip along the span direction of the wind turbine blade 1. The main metal mesh is divided into a main metal mesh 1 5 and a main metal mesh 2 6. The two are connected in series through a metal sheet 13 ( Figure 4 The blade tip lightning receptor 10 is set at the front end of the blade, and the blade body lightning receptor 8 is distributed on the pressure surface and suction surface of the middle and rear part of the blade ( Figure 3 ), the main metal mesh 17 in the figure is one between the main metal mesh 1 5 and the main metal mesh 2 6, which is convenient for observation and understanding.

[0021] The blade root metal mesh grounding piece includes a blade root metal mesh 1 4 and a blade root metal mesh grounding piece 25; The blade tip metal mesh grounding piece includes a blade tip metal mesh grounding piece 1 27 and a blade tip metal mesh grounding piece 26; The material of the main metal mesh 1 5 and the main metal mesh 2 6 is copper, aluminum, nickel or other metals, preferably copper; The mass per unit area of ​​the metal mesh system 21 is distributed in a gradient along the blade span and satisfies: The low-weight region 22 has a mass per unit area of ​​50-500 g / m². In one embodiment, the low-weight region 22 has a mass per unit area of ​​50 g / m²; in one embodiment, the low-weight region 22 has a mass per unit area of ​​500 g / m²; in one embodiment, the low-weight region 22 has a mass per unit area of ​​250 g / m²; The mass per unit area of ​​the transition zone 23 increases linearly to 400-600 g / m². In one embodiment, the mass per unit area of ​​the transition zone 23 increases linearly to 400 g / m²; in one embodiment, the mass per unit area of ​​the transition zone 23 increases linearly to 600 g / m²; in one embodiment, the mass per unit area of ​​the transition zone 23 increases linearly to 500 g / m²; The high-weight region 24 has a mass per unit area of ​​500-1000 g / m². In one embodiment, the high-weight region 24 has a mass per unit area of ​​500 g / m²; in one embodiment, the high-weight region 24 has a mass per unit area of ​​1000 g / m²; and in one embodiment, the high-weight region 24 has a mass per unit area of ​​800 g / m².

[0022] refer to Figure 5 、 Figure 6 、 Figure 7 and Figure 8 , low gram weight area 22: from the root of the leaf to 70% of the leaf length, a woven copper mesh is used to ensure its conductivity; Transition zone 23: 70%–75% leaf length region, where the weight is linearly increased to 200–500 g / m² by gradually increasing the metal wire density. In one embodiment, the weight is linearly increased to 200 g / m² by gradually increasing the metal wire density in the 70% leaf length region; in one embodiment, the weight is linearly increased to 500 g / m² by gradually increasing the metal wire density in the 75% leaf length region; and in one embodiment, the weight is linearly increased to 300 g / m² by gradually increasing the metal wire density in the 72% leaf length region.

[0023] High-weight area 24: 75% to the blade tip range uses copper mesh to completely cover the area around the blade tip lightning receptor 10 ( Figure 7 ).

[0024] The low-weight region 22 is arranged from the blade root to the blade midsection, the transition region 23 is arranged in the blade midsection, and the high-weight region 24 is arranged within the blade tip range.

[0025] The high-weight area 24 extends to cover the range of 5m from the blade tip. The metal mesh distributed on the two surfaces is connected in series with the down conductor system and is directly connected to the blade tip lightning receptor 10 or the blade tip lightning receptor 8 through the metal sheet 13 or the conductive adhesive layer.

[0026] refer to Figure 8 As shown, the blank areas on both sides of the high-weight area 24 are cutting areas.

[0027] One end of the tip down conductor 9 is connected to the blade tip lightning rod 10 and the blade body lightning rod 8 arranged at the tip of the wind turbine blade 1, and the other end of the tip down conductor 9 includes a grounding base 14 connected in series to the high-weight area 24 of the metal mesh system 21.

[0028] Tip reinforcement connection: The metal mesh in the high-weight area 24 is fixed with soldering by metal sheets 13 and extends to the bottom of the blade body lightning receptor base or the blade tip lightning receptor 10 in the tip area, ensuring that the lightning current is directly introduced into the metal mesh.

[0029] The electrical connection between the metal mesh and the lightning receptor is achieved through the lightning receptor 21 .

[0030] Grounding path: One end of the root down conductor 3 is bolted to the copper mesh in the low-weight area 22, and the other end is connected to the blade root grounding piece 2 embedded in the carbon beam; The metal mesh system 21 is connected to the grounding base 14 and the grounding base 2 7 through the metal mesh grounding piece 11 and the metal mesh grounding piece 2 12 to form a single-loop discharge channel ( Figure 2 ).

[0031] One end of the tip down conductor 9 is connected to the blade tip lightning receptor 10 , and the other end of the tip down conductor 9 is connected in series to the high-weight area 24 of the metal mesh system 21 .

[0032] One end of the root down conductor 3 is connected to the low-weight area 22 of the metal mesh system 21 , and the other end of the root down conductor 3 is connected to the blade root grounding piece 2 .

[0033] refer to Figure 2 As shown, the main metal mesh 1-5 is provided with a blade root grounding metal mesh 1-4, a main metal mesh 17, and a blade tip metal mesh grounding piece 1-27, and the main metal mesh 2-6 is provided with a blade root metal mesh grounding piece 2-25 and a blade tip metal mesh grounding piece 2-26. The blade tip metal mesh grounding piece 1-27 and the blade tip metal mesh grounding piece 2-26 have the same function as the blade root metal mesh grounding piece 1-11 and the blade root metal mesh grounding piece 2-12, but are located at different positions on the wind turbine blade 1, and will not be described in detail in this application.

[0034] It should be noted that the blade root grounding metal mesh 1 4 and the blade root metal mesh grounding piece 2 25 are arranged on the blade root, and the blade tip metal mesh grounding piece 1 27 and the blade tip metal mesh grounding piece 2 26 are arranged on the blade tip.

[0035] The metal mesh system 21 is composed of a metal mesh grounding member 11, a metal mesh grounding member 2 12 and a main metal mesh 17, and is connected to a grounding base 14 and a grounding base 2 7 to form a single-loop lightning current conduction path.

[0036] It should be noted that the metal mesh substrate is made of metals such as copper, aluminum, and nickel, with copper being preferred.

[0037] Working principle: When lightning strikes the blade tip lightning receptor 10 or the blade body lightning receptor 8: Lightning current induction: The blade tip lightning current is directly introduced into the copper mesh of the high-weight area 24 through the tip down conductor 9; The blade lightning current is introduced into the metal mesh system 21 nearby by the blade lightning receptor 8.

[0038] Gradient conduction process: The high-weight area 24 uses high conductivity (copper mesh) and dense structure to carry the initial high-amplitude lightning current (200kA level); During the current conduction to the blade root, the linear weight increasing structure of the transition zone 23 suppresses the current mutation and avoids local arcing; The current attenuated to a low amplitude (<50 kA) reaches the low-weight area 22 and is conducted to the root down conductor 3 by the copper mesh.

[0039] Ground discharge: The current is finally discharged to the wind turbine tower grounding system through the blade root grounding piece 2, completing the single-loop conduction ( Figure 2 ).

[0040] Through differentiated weight design, gradient technology strengthens protection in the high lightning strike risk area at the blade tip, while reducing weight in the blade root area, achieving an optimized balance between lightning protection performance and blade load.

[0041] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0042] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A metal mesh series down conductor lightning protection system based on gradient technology, comprising a wind turbine blade (1) and a root grounding member (2), characterized in that: The wind turbine blade (1) is provided with a metal mesh series down conductor lightning protection system, comprising: A metal mesh system (21), the metal mesh system (21) is laid along the blade span direction and arranged in series, the metal mesh system (21) comprising a main metal mesh (17), a blade root metal mesh grounding piece, and a blade tip metal mesh grounding piece; A down conductor assembly, the down conductor assembly comprising a root down conductor (3) and a tip down conductor (9), the down conductor assembly being connected in series with the metal mesh system (21); A lightning termination system, comprising a blade body lightning termination device (8) and a blade tip lightning termination device (10), wherein the blade body lightning termination device (8) and the blade tip lightning termination device (10) are arranged on the surface of a wind turbine blade (1); The mass per unit area of ​​the main metal mesh (17) is distributed in a gradient along the span direction of the blade, forming a low-weight area (22), a transition area (23) and a high-weight area (24), wherein the high-weight area (24) covers the blade tip area, and the mass per unit area of ​​the metal mesh system (21) is distributed in a gradient along the span direction of the wind turbine blade (1), including at least one group of transition areas (23).

2. The metal mesh series downconductor lightning protection system based on gradient technology according to claim 1 is characterized by: The metal mesh series down conductor lightning protection system is distributed on at least one surface of a wind turbine blade (1), and the metal mesh series down conductor lightning protection systems distributed on two surfaces are connected in a conductive stitching structure through overlapping metal sheets (13) to form a continuous conductive path.

3. The metal mesh series downconductor lightning protection system based on gradient technology according to claim 2 is characterized by: The low gram weight region (22) is arranged from the blade root to the blade midsection, the transition region (23) is arranged at the blade midsection, and the high gram weight region (24) is arranged at the blade tip section.

4. The metal mesh series downconductor lightning protection system based on gradient technology according to claim 3 is characterized by: The mass per unit area of ​​the metal mesh system (21) is distributed in a gradient along the blade span direction.

5. The metal mesh series downconductor lightning protection system based on gradient technology according to claim 4 is characterized in that: The high-weight area (24) extends to cover the blade tip and is directly connected to the blade tip lightning receptor (10) or the blade body lightning receptor (8) via a metal sheet (13) or a conductive adhesive layer.

6. The metal mesh series downconductor lightning protection system based on gradient technology according to claim 5 is characterized by: One end of the tip down conductor (9) is connected to a blade tip lightning receptor (10) and a blade body lightning receptor (8) arranged at the tip of the wind turbine blade (1), and the other end of the tip down conductor (9) comprises a high-weight area (24) connected in series to a grounding base (14) and a metal mesh system (21).

7. The metal mesh series downconductor lightning protection system based on gradient technology according to claim 6 is characterized by: One end of the root down conductor (3) is connected to the low-weight area (22) of the metal mesh system (21), and the other end of the root down conductor (3) includes a second grounding base (7) connected to the blade root grounding piece (2).

8. The metal mesh series downconductor lightning protection system based on gradient technology according to claim 7 is characterized by: The main metal mesh 1 (5) is provided with a metal mesh grounding piece 1 (11), and the main metal mesh 2 (6) is provided with a metal mesh grounding piece 2 (12).

9. The metal mesh series downconductor lightning protection system based on gradient technology according to claim 8 is characterized by: The metal mesh system (21) is connected to the grounding base 1 (14) and the grounding base 2 (7) through the metal mesh grounding piece 1 (11) and the metal mesh grounding piece 2 (12), thereby forming a single-loop lightning current conduction path.

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