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EP-4741651-A1 - A WIND TURBINE ROTOR BLADE WITH AN ELECTRICAL HEATING SYSTEM

EP4741651A1EP 4741651 A1EP4741651 A1EP 4741651A1EP-4741651-A1

Abstract

A wind turbine rotor blade comprising a blade root, a blade tip, a leading edge, a trailing edge, a suction side, a pressure side (22) and a heatable surface area including at least one electrical heating element, wherein the heatable surface area covers a section of the leading edge and has a first edge facing the blade tip, a second edge facing the blade root, a third edge arranged on the suction side and a fourth edge arranged on the pressure side (22), characterized in that the wind turbine rotor blade comprises a first layer of an electrically insulating material, wherein the first layer is smaller than the heatable surface area and is arranged on top of the at least one electrical heating element along the leading edge and such that it extends beyond the first edge.

Inventors

  • KREMER, JOCHEN
  • LIPKA, THOMAS

Assignees

  • Nordex Energy SE & Co. KG

Dates

Publication Date
20260513
Application Date
20241107

Claims (15)

  1. A wind turbine rotor blade (10) comprising a blade root (12), a blade tip (14 a leading edge (16), a trailing edge (18), a suction side (20), a pressure side (22) and a heatable surface area (26) including at least one electrical heating element (24), wherein the heatable surface area (26) covers a section of the leading edge (16) and has a first edge (26a) facing the blade tip (14), a second edge (26b) facing the blade root (12), a third edge (26c) arranged on the suction side (20) and a fourth edge (26d) arranged on the pressure side (22), characterized in that the wind turbine rotor blade (10) comprises a first layer (48) of an electrically insulating material, wherein the first layer (48) is smaller than the heatable surface area (26) and is arranged on top of the at least one electrical heating element (24) along the leading edge (16) and such that the first layer (48) extends beyond the first edge (26a) of the heatable surface area (26).
  2. The wind turbine rotor blade (10) of claim 1, wherein the first layer (48) has a second edge (48b) facing the blade root (12), wherein at least a section of the second edge (48b) of the first layer (48) is arranged on top of the heatable surface area (26) in a distance from the second edge (26b) of the heatable surface area (26).
  3. The wind turbine rotor blade (10) of claim 1 or 2, wherein the first layer (48) has a third edge (48c) on the suction side (20), wherein at least a section of the third edge (48c) of the first layer (48) is arranged on top of the heatable surface area (26) in a distance from the third edge (26c) of the heatable surface area (26), and/or wherein the first layer (48) has a fourth edge (48d) on the pressure side (22), wherein at least a section of the fourth edge (48d) of the first layer (48) is arranged on top of the heatable surface area (26) in a distance from the fourth edge (26d) of the heatable surface area (26).
  4. The wind turbine rotor blade (10) of any of the claims 1 to 3, wherein the wind turbine rotor blade (10) comprises a second layer (50) of an electrically insulating material, wherein the second layer (50) is smaller than the heatable surface area (26) and is arranged on top of the at least one electrical heating element (24) along the leading edge (16) and such that it extends beyond the first edge (26a) of the heatable surface area (26).
  5. The wind turbine rotor blade (10) of claim 4, wherein the first edge (50a) of the second layer (50) in a longitudinal direction is arranged between the first edge (26a) of the heatable surface area (26) and the first edge (48a) of the first layer (48).
  6. The wind turbine rotor blade (10) of claim 4 or 5, wherein the second layer (50) has a second edge (50b) facing the blade root (12), wherein at least a section of the second edge (50b) of the second layer (50) is arranged within a surface covered by the first layer (48) and in a distance from the second edge (48b) of the first layer (48).
  7. The wind turbine rotor blade (10) of any of the claims 4 to 6, wherein the second layer (50) has a third edge (50c) on the suction side (20), wherein at least a section of the third edge (50c) of the second layer (50) is arranged within a surface covered by the first layer (48) and in a predetermined distance from the third edge (48c) of the first layer (48), and/or wherein the second layer (50) has a fourth edge (50d) on the pressure side (22), wherein at least a section of the fourth edge (50d) of the second layer (50) is arranged within a surface covered by the first layer (48) and in a distance from the fourth edge (48d) of the first layer (48).
  8. The wind turbine rotor blade (10) of any of the claims 4 to 7, wherein the wind turbine rotor blade (10) comprises a third layer (52) of an electrically insulating material, wherein the third layer (52) is smaller than the heatable surface area (26) and is arranged on top of the at least one electrical heating element (24) along the leading edge (16) and such that it extends beyond the first edge (26a) of the heatable surface area (26), wherein the third layer (52) is arranged with reference to the second layer (50) in the same manner as is defined in any of the claims 4 to 7 for the second layer (50) with reference to the first layer (48).
  9. The wind turbine rotor blade (10) of any of the claims 1 to 8, wherein the at least one electrical heating element (24) comprises a plurality of electrical heating elements (24) arranged in a row along the leading edge (16), wherein each of the heating elements (24) has a first edge facing the blade tip (14) and a second edge facing the blade root (12), wherein the wind turbine rotor blade (10) comprises at least one strip (46) of an electrically insulating material arranged on top of a first edge of one of the heating elements (24) and on top of a second edge of an adjacent one of the heating element (24)s.
  10. The wind turbine rotor blade (10) of any of the claims 1 to 9, wherein the at least one electrical heating element (24) comprises a plurality of electrical heating elements (24) arranged in a row along the leading edge (16), wherein each of the heating elements (24) has a first connecting section (40) connected to a first electrical supply line on the suction side (20) and a second connecting section (40) connected to a second electrical supply line (38) on the suction side (20), wherein the wind turbine rotor blade (10) comprises at least one strip (44) of an electrically insulating material arranged on top of the first connecting section (40) and/or on top of the second connecting section (40).
  11. The wind turbine rotor blade (10) of claim 10, wherein the first electrical supply line is arranged between the trailing edge (18) and the third edge (26c) of the heatable surface area (26), wherein the at least one strip (44) of an electrically insulating material arranged on top of the first connecting section (40) extends from the third edge (26c) of the heatable surface area (26) to the first electrical supply line or beyond and/or wherein the second electrical supply line (38) is arranged between the trailing edge (18) and the fourth edge (26d) of the heatable surface area (26), wherein the at least one strip (44) of an electrically insulating material arranged on top of the second connecting section (40) extends from the fourth edge (26d) of the heatable surface area (26) to the second electrical supply (38) line or beyond.
  12. The wind turbine rotor blade (10) of any of the claims 1 to 11, wherein the wind turbine rotor blade (10) comprises a lightning receptor arranged at the blade tip (14), wherein the first edge (26a) of the heatable surface area (26) is arranged in a distance in the range of 1 m to 4 m from the blade tip (14).
  13. The wind turbine rotor blade (10) of any of the claims 1 to 12, wherein the wind turbine rotor blade (10) comprises at least one additional lightning receptor arranged between the trailing edge (18) and the third edge (26c) of the heatable surface area (26) and/or between the trailing edge (18) and the fourth edge (26d) of the heatable surface area (26).
  14. The wind turbine rotor blade (10) of any of the claims 1 to 13, wherein the insulating material comprises glass fibers.
  15. The wind turbine rotor blade (10) of any of the claims 1 to 14, wherein the at least one electrical heating element (24) comprises a heating conductor fastened to a carrier layerwind turbine rotor blade (10), wherein in particular the heating conductor comprises a metal heating wire or a bundle of carbon fibers.

Description

The invention relates to a heating system for a wind turbine rotor blade with an electrical heating system. EP 2 667 025 A1 discloses a wind turbine rotor blade with a heating mat having two segments running in parallel along a longitudinal direction of the wind turbine rotor blade. To avoid a short circuit between the two segments, a layer of an insulating material is placed between the adjacent segments, wherein the layer is arranged underneath one of the two segments and on top of the adjacent segment. EP 2 843 228 A1 discloses a wind turbine rotor blade with an electrical heating system including a plurality of electrical heating elements arranged on an outer surface of the wind turbine rotor blade. Each of the heating elements has a carrier layer and a heating conductor arranged on the carrier layer between two opposite edges of the heating element in a meandering pattern. The heating elements are arranged on an outer surface of the wind turbine rotor blade. Free ends of each heating conductor are connected to two electrical supply lines which are running along a length of the blade and also serve as lightning down conductors. In case of lightning, the heating elements shall provide potential equalization between the two lightning down conductors. An outer side of the heating elements is provided with an erosion protection layer. Departing therefrom, it is an object of the invention to provide a wind turbine rotor blade with an electrical heating system that offers improved lightning protection. This object is solved by the wind turbine rotor blade with the features of claim 1. Aspects of the invention are indicated in the dependent claims. The wind turbine rotor blade comprises a blade root, a blade tip, , a leading edge, a trailing edge, a suction side, a pressure side and a heatable surface area including at least one electrical heating element, wherein the heatable surface area covers a section of the leading edge and has a first edge facing the blade tip, a second edge facing the blade root, a third edge arranged on the suction side and a fourth edge arranged on the pressure side, wherein the wind turbine rotor blade comprises a first layer of an electrically insulating material, wherein the first layer is smaller than the heatable surface area and is arranged on top of the at least one electrical heating element along the leading edge and such that it extends beyond the first edge. The wind turbine rotor blade has an outer surface which corresponds to an aerodynamic surface of the wind turbine rotor blade. The wind turbine rotor blade may comprise a shell structure forming the outer surface, for example comprising two wind turbine rotor blade half shells, such as a pressure side half shell and a suction side half shell. The at least one heating element can be connected to first and second electrical supply lines so that a heating current can be guided through the at least one heating element. In this manner, the at least one heating element and the heatable surface area of the wind turbine rotor blade can be heated in order to remove accumulated ice (de-icing) and/or in order to prevent the formation of ice (anti-icing) on this surface area. The at least one heating element may have an essentially rectangular or trapezoidal shape which is folded about the leading edge of the wind turbine rotor blade. The shape of the at least one heating element defines the heatable surface area. Typically, a plurality of heating elements will be arranged on the outer surface of the wind turbine rotor blade, together defining the heatable surface area. The invention is based on the observation that lightning striking a wind turbine rotor blade with a suitable lightning protection system may not only damage any electrically conducting elements within the wind turbine rotor blade which are arranged near a lightning down conductor, caused by flashovers between the lightning down conductor and the electrically conducting element. In addition, the heating elements themselves may get struck by a direct lightning strike when under the influence of a high electric field strength free charge carriers (electrons or ions) are accelerated out of the heating element and contribute to the formation of a current channel. This risk may be reduced by an electrical isolation of the heating elements. However, any isolating material placed on top of the heating elements adds to the total weight of the wind turbine rotor blade and also potentially reduces the efficiency of the heating system. The isolating material may also decrease the aerodynamic performance of the wind turbine rotor blade due to unwanted alterations of the surface geometry and surface structure. Based on these considerations, the inventors found a way to achieve a significant reduction in the risk of direct lightning strikes affecting the at least one heating element using a minimum of additional material and being easy to implement. The first layer of electricall