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EP-3708828-B1 - A METHOD FOR PROVIDING A WIND TURBINE BLADE WITH LIGHTNING PROTECTION AND A WIND TURBINE BLADE

EP3708828B1EP 3708828 B1EP3708828 B1EP 3708828B1EP-3708828-B1

Inventors

  • Leong, Martin

Dates

Publication Date
20260506
Application Date
20190314

Claims (13)

  1. A method for providing a wind turbine blade (1) with lightning protection, the method comprising the steps of: providing a lightning protection cover (2) comprising a non-conductive medium (3) and a conductive medium (4) embedded in the non-conductive medium (3), and providing a blade body (5), the method being characterized in that it further comprises the step of: attaching the lightning protection cover (2) to the blade body (5) with an adhesive medium (7), wherein the adhesive medium (7) is configured to allow a reversible attachment of the lightning protection cover (2) to the blade body (5).
  2. The method according to claim 1, wherein the adhesive medium (7) is an epoxy-based glue.
  3. The method according to claim 1 or 2, further comprising applying the adhesive medium (7) to the non-conductive medium (3) before attaching the lightning protection cover (2) to the blade body (5).
  4. The method according to one of claims 1 - 3, wherein attaching the lightning protection cover (2) comprises bending the lightning protection cover (2) to follow the shape of the blade body (5).
  5. The method according to one of claims 1 - 4, wherein attaching the lightning protection cover (2) comprises fully surrounding, with the lightning protection cover (2), the blade body (5) when seen in a cross section taken at right angles to the blade body's longitudinal axis (L).
  6. The method according to one of claims 1 - 5, wherein attaching the lightning protection cover (2) comprises encasing, with the lightning protection cover (2), a tip (6) of the blade body (5).
  7. The method according to one of claims 1 - 6, further comprising: identifying a defective area (9) on or within the blade body (5), and attaching the lightning protection cover (2) on top of the defective area (9) to the blade body (5).
  8. The method according to claim 7, wherein the defective area (9) is identified using an X-ray analysis and/or a high-frequency measurement.
  9. The method according to one of claims 1 - 8, further comprising electrically connecting (14, 14') the conductive medium (4) of the lightning protection cover (2) to ground (11), preferably using a lightning protection system (12) of the wind turbine (10).
  10. The method according to one of claims 1 - 9, further comprising attaching a further lightning protection cover (2'), comprising a non-conductive medium (3) and a conductive medium (4) embedded in the non-conductive medium (3), to the blade body (5) of the wind turbine blade (1) and connecting the conductive medium (4) of the lightning protection cover (2) to the conductive medium (4) of the further lightning protection cover (2').
  11. The method according to one of claims 1 - 10, wherein the conductive medium (4) is a metallic mesh or a metallic foil.
  12. The method according to one of claims 1 - 11, wherein the non-conductive medium (3) comprises a polymer.
  13. A wind turbine blade (1), comprising: a blade body (5), and a lightning protection cover (2) reversibly attached to the blade body (5) with an adhesive medium (7), the lightning protection cover (2) comprising: a non-conductive medium (3), and a conductive medium (4) embedded in the non-conductive medium (3).

Description

The present invention relates to a method for providing a wind turbine blade with lightning protection and a corresponding wind turbine blade. Lightning damage is one of the primary drivers of operation and maintenance cost for wind turbine blades during operation since even wind turbine blades with a fully functional lightning protection system can be subjected to damage during a lightning event. Typical damages can range from being superficial to compromising the structural integrity of a wind turbine blade. Such damage may necessitate repair work on the wind turbine blade using a crane which is costly and time-consuming. Moreover, variations in the production of wind turbine blades can potentially increase the risk of a lightning strike damaging the wind turbine blade. Variations may be random or systematic and may be represented by air pockets in the laminate of the wind turbine blade or by casting in foreign objects. Although such variations would otherwise not compromise the integrity or performance of the wind turbine blade and the wind turbine in general, the likelihood of a damage caused by a lightning strike is increased. Conventionally, operators of wind turbines follow a reactive approach which involves waiting until a damage caused by a lightning strike occurs and subsequently repairing the damage by up-tower means or replacement of the wind turbine blade. Moreover, a known proactive remediation of variations in the blade which have been identified comprises grinding of the laminate of the wind turbine blade until a variation has been removed and afterwards restoring the laminate by hand lamination using a lifting platform or a rope access. According to an alternative solution, a wind turbine blade is even lowered to the ground for repair work or replacement. US 2010/0047074 A1 discloses an example of a wind turbine lightning protection system which comprises a blade, wherein a tip portion of the blade may comprise a conductive material like a metal mesh and the remaining part of the blade is optionally covered by paint which may be conductive, semiconductive or non-conductive. Further, US 2010/329881 A1 discloses another example of a lightning protection system for a wind turbine, wherein a metal mesh or a metal foil is incorporated into a skin material of a wind turbine blade. Further, WO 2015/185065 A1 discloses a preformed component of a lightning protection system for a wind turbine blade, the preformed component comprising a sheet of conductive material having an edge that defines a perimeter of the sheet, wherein an edge protection structure is attached to the sheet so as to envelop the edge along at least a portion of the perimeter. The edge protection structure serves to protect surround parts of the blade from sharp parts of the sheet of conductive material. The invention also extends to a method of forming a preformed component, to an edge protection structure and also to a storage solution for such an edge protection structure. Further, EP 2 963 289 A1 discloses a wind turbine blade including: a blade root portion forming a root of the wind turbine blade; a blade tip portion forming a tip of the wind turbine blade; a main mesh extending continuously between the blade tip portion and the blade root portion, the main mesh having conductivity and forming a conductive path for conducting lightning current; a repair mesh disposed on a damaged section of the main mesh which interrupts a flow of the lightning current, the repair mesh including a mesh piece for compensating for the conductive path formed by the main mesh; and an electrical connecting portion for electrically connecting the main mesh and the repair mesh with each other. WO 2018/219511 A1 discloses an insulation of a heating mat of a wind turbine blade. WO 2018/060297 A1 discloses a protective cover system for protecting a leading edge of a wind turbine blade. It is one object of the present invention to provide an improved method for reducing damage to wind turbine blades and a corresponding wind turbine blade. Accordingly, a method for providing a wind turbine blade with lightning protection according to claim 1 is provided. The method is advantageous in that a lightning protection can be proactively provided for a wind turbine blade with low installation effort since cumbersome grinding and hand lamination processes are not required. Moreover, lowering the wind turbine blade may also not be required anymore since the installation of the lightning protection can be conducted faster due to its simplicity. In addition to that, the wind turbine blade itself may be better protected when hit by lightning since the lightning protection cover is attached to the blade body but does not form an integral part of the blade. Hence, by covering a certain area of the blade body, for example where a systematic variation (in particular defect) is expected, it is possible to effectively protect the structure of the wind turbine blade from l