Search

CN-122014543-A - Lightning protection system

CN122014543ACN 122014543 ACN122014543 ACN 122014543ACN-122014543-A

Abstract

The invention relates to a lightning protection system for a wind turbine blade comprising a root end and a tip end and a longitudinal axis, a pressure side and a suction side, and a structural element extending along the longitudinal axis, the pressure side and the suction side being external surfaces of the wind turbine blade, the structural element being a rod or beam made of a Fibre Reinforced Polymer (FRP), the lightning protection system comprising a first down conductor, a second down conductor and a third down conductor, the second down conductor comprising a first expansion foil or a first net, and the third down conductor comprising a second expansion foil or a second net, the first expansion foil or the first net and the second expansion foil or the second net being made of an electrically conductive material and comprising a plurality of electrically conductive connection points arranged near the top connection block and the root connection block, and being electrically connected with the top connection block and the root connection block, respectively, whereby the wind turbine blade can be protected from structural damage caused by lightning impulse over the entire length.

Inventors

  • Max Kilcko
  • RICHARD BECK
  • Lisa Karoney

Assignees

  • 保利泰克有限公司

Dates

Publication Date
20260512
Application Date
20211223
Priority Date
20201223

Claims (15)

  1. 1. A lightning protection system (1) for a wind turbine blade (101), the wind turbine blade (101) comprising: a root end (102) and a tip end (103) and a longitudinal axis (106); A pressure side (110) and a suction side (111), which are the outer surfaces of the wind turbine blade, and A structural element (112) extending along the longitudinal axis, the structural element being a rod or beam made of a Fiber Reinforced Polymer (FRP), The lightning protection system comprises: -a first down conductor (2) extending from the top end (103) to a top connection block (3) arranged at a predetermined distance from the top end, the first down conductor (2) being electrically connected to the top connection block, -A second down-conductor (4) extending from the top connection block (3) between the structural element (112) and the pressure side (110) along the structural element and the pressure side towards a root connection block (5) arranged at the root end (102), -A third down conductor (7) extending from the top connection block (3) between the structural element (112) and the suction side (111) along the structural element and the suction side towards the root connection block (5), -The second down conductor (4) comprises a first expanded foil or a first mesh and the third down conductor (7) comprises a second expanded foil or a second mesh, the first expanded foil or first mesh and the second expanded foil or second mesh being made of an electrically conductive material, The first expansion foil or first net and the second expansion foil or second net comprise a plurality of electrically conductive connection points (6), which electrically conductive connection points (6) are arranged in the vicinity of the top connection block (3) and the root connection block (5) and are electrically connected with the top connection block (3) and the root connection block (5), respectively.
  2. 2. Lightning protection system (1) according to claim 1, wherein the structural element (112) is a rod or beam made of an electrically conductive Carbon Fiber Reinforced Polymer (CFRP).
  3. 3. Lightning protection system (1) according to claim 1 or 2, wherein the predetermined distance is about 5 to 25 meters from the tip (103).
  4. 4. Lightning protection system (1) according to any of the preceding claims, wherein the first expansion foil or first mesh and the second expansion foil or second mesh are symmetrically arranged on opposite sides with respect to the structural element (112) and are substantially equal in size.
  5. 5. The lightning protection system (1) according to any of the preceding claims, wherein: the conductive connection point (6) is made of metal or other conductive material or a combination thereof, and/or The electrically conductive connection point (6) is directly or indirectly connected to the connection block (3, 5), and/or Each conductive connection point (6) has a geometry exhibiting an external closed curve (8) with a minimum radius of curvature between 3 mm and 200 mm, preferably between 5mm and 100 mm, and/or The conductive connection point (6) has a semi-major axis (9) and a semi-minor axis (10), wherein the semi-major axis (9) and the semi-minor axis (10) are preferably different, providing an oval or elliptical outer perimeter (11), and/or The electrically conductive connection point (6) has a semi-major axis (9) and a semi-minor axis (10), wherein the semi-major axis (9) is oriented at a predetermined angle with respect to a longitudinal axis (106) of the wind turbine blade, wherein the predetermined angle is preferably between 0 and 90 degrees, and/or The electrically conductive connection point (6) has an edge or outer periphery at which the current density is no more than 1500A/mm, and/or The conductive connection point (6) has a thickness which is greater than 0.5mm, preferably greater than 1.0 mm, wherein the thickness of the conductive connection point (6) preferably extends in both directions relative to the thickness of the sheet.
  6. 6. Lightning protection system (1) according to any of the preceding claims, wherein receptor bolts are screwed into the connection block through the electrically conductive connection points (6).
  7. 7. Lightning protection system (1) according to any of the preceding claims, wherein a plurality of intermediate electrically conductive connection points (12) are arranged oppositely with respect to the structural element (112) at a predetermined intermediate distance from the top connection block (3), wherein the intermediate electrically conductive connection points (12) are preferably connected with the structural element (112).
  8. 8. Lightning protection system (1) according to claim 7, wherein the predetermined intermediate distance is less than 1500 mm, preferably between 1500 mm and 500 mm, more preferably between 500 mm and 100 mm, most preferably between 100 mm and 10 mm.
  9. 9. Lightning protection system (1) according to any of the preceding claims, wherein the electrically conductive material of the first expansion foil or first mesh and the second expansion foil or second mesh is a metal, such as aluminium, copper, steel or an associated alloy.
  10. 10. Lightning protection system (1) according to any of the preceding claims, wherein the first expansion foil or first mesh is arranged such that it at least completely covers a first side of the structural element (112) facing the pressure side (110) and the second expansion foil or second mesh is arranged such that it at least completely covers a second side of the structural element (112) facing the suction side (111), Wherein the length of the first expanded foil or first web and the second expanded foil or second web is preferably equal to or longer than the length of the structural element (112).
  11. 11. The lightning protection system (1) according to any of the preceding claims, wherein the top connection block (3): Electrically connecting the first down conductor (2) with the first expansion foil or first mesh and the second expansion foil or second mesh, respectively, via the electrically conductive connection point (6), and/or Comprises at least one first receptacle base and at least one second receptacle base, the first receptacle base being configured to connect the electrically conductive connection points (6) of the first expansion foil or first net to the top connection block (3), and the second receptacle base being configured to connect the electrically conductive connection points (6) of the second expansion foil or second net to the top connection block (3).
  12. 12. Lightning protection system (1) according to any of the preceding claims, wherein the root connection block (5) is configured to electrically connect the first expansion foil or first net and the second expansion foil or second net with a single root down conductor (24).
  13. 13. A wind turbine blade (101), comprising: a root end (102) and a tip end (103) and a longitudinal axis (106), A pressure side (110) and a suction side (111), the pressure side and the suction side being outer surfaces of the wind turbine blade, and -A structural element (112) extending along the longitudinal axis (106), the structural element (112) being a rod or beam made of an electrically conductive Carbon Fiber Reinforced Polymer (CFRP), and Lightning protection system (1) according to any of the preceding claims.
  14. 14. A wind turbine (100) having one or more wind turbine blades (101) with a lightning protection system (1) according to any of claims 1 to 12.
  15. 15. Method for arranging an electrically conductive connection point (6) of a lightning protection system (1) according to any of claims 1 to 12 on an intumescent foil or mesh, comprising a method according to step a) or step B): wherein the method according to step a) comprises: -melting the electrically conductive material, Applying a liquid molten conductive material around the expanded foil or mesh, -Solidifying the molten material to provide a mechanical and electrically conductive connection between the electrically conductive connection point and the expanded foil or mesh; wherein the method according to step B) comprises: providing at least two discs made of electrically conductive material, Two discs are arranged on opposite sides of the expanded foil or mesh, -Fastening the discs to each other with the expanded foil or mesh sandwiched between the discs to form an electrically conductive connection between the expanded foil or mesh and the discs.

Description

Lightning protection system The application is a divisional application of a Chinese patent application 'lightning protection system' with the application date of 2021, 12, 23, the priority date of 2020, 12, 23 and the application number of 202180087173. X. Technical Field The present invention relates to a lightning protection system for a wind turbine blade comprising a root end and a tip end and a longitudinal axis, a pressure side and a suction side, which are the outer surfaces of the wind turbine blade, and structural elements extending along the longitudinal axis, which are rods or beams made of Fibre Reinforced Polymer (FRP). Background Most known lightning protection systems for wind turbine blades comprise one or more down conductors arranged internally and a plurality of lightning receptors arranged on the external surface of the blade. A well-known problem with such systems is that lightning strikes are not only attached to the wind turbine blade at the intended location, i.e. at the external attachment point (so-called lightning receptor), but may also strike the internal conductive part of the lightning protection system directly through the structure of the blade. Due to the large amount of energy typically released in connection with lightning impulse, such events may cause serious structural damage to the wind turbine blade. As the size of wind turbines increases, so does the size of the wind turbine blades. Consequently, the structural design of wind turbine blades is becoming increasingly important, as it is always desirable to design wind turbine blades as light as possible without compromising the strength of the wind turbine blade. It is therefore even more important to protect the wind turbine blades over their entire length from structural damage caused by lightning strikes. Disclosure of Invention The present invention aims to wholly or partly overcome the above-mentioned disadvantages and drawbacks of the prior art. More specifically, it is an object to provide an improved lightning protection system for a wind turbine blade having a structural element being a rod or beam made of Fiber Reinforced Polymer (FRP). The above objects, together with numerous other objects, advantages, and features, which will become evident from the below description, are accomplished by a solution in accordance with the present invention by a lightning protection system for a wind turbine blade comprising a root end and a tip end and a longitudinal axis, a pressure side and a suction side, and a structural element extending along the longitudinal axis, the pressure side and the suction side being an outer surface of the wind turbine blade, the structural element being a rod or beam made of a Fiber Reinforced Polymer (FRP), the lightning protection system comprising: A first down conductor extending from the top end to a top connection block, the top connection block being arranged at a predetermined distance from the top end, the first down conductor being electrically connected to the top connection block, A second down conductor extending from the top connection block between the structural element and the pressure side and along the structural element and the pressure side towards a root connection block arranged at the root end, A third down conductor extending from the top connection block between the structural element and the suction side and along the structural element and the suction side towards the root connection block, The second down conductor comprises a first sheet and the third down conductor comprises a second sheet, the first sheet and the second sheet being made entirely or partly of an electrically conductive material, The first sheet and the second sheet include a plurality of conductive connection points disposed near the top connection block and the root connection block and electrically connected to the top connection block and the root connection block, respectively. Thus, the top connection block serves as an interface between a first down conductor extending from the top of the wind turbine blade and two sheets in each blade shell, which serve as down conductors from the tip of the FRP rod cap. In addition, bonding or equipotential between the pressure side down conductor and the suction side down conductor is performed in one unit. At the same time, the second down conductor and the third down conductor may be used as receptor bases for lightning strike attachment to the sheet tip. This portion is carefully designed to handle the full lightning current and avoid interception faults due to its insulating castings. Furthermore, the structural element may be a rod or beam made of an electrically conductive Carbon Fiber Reinforced Polymer (CFRP). Depending on the total length of the wind turbine blade, the predetermined distance may be 5 meters to 25 meters from the tip of the wind turbine blade. Furthermore, the first expanded foil or first web and the second expanded foil or