Wind turbine blade comprising a lightning protection system equipped with radar absorbing material

Patent metadata

Field	Value
Publication number	US-10330075-B2
Application number	US-201615337838-A
Country	US
Kind code	B2
Filing date	Oct 28, 2016
Priority date	Nov 24, 2015
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

The invention provides a wind turbine blade having a Radar Absorbing Material (RAM) and a lightning protection system arranged for guaranteeing the performance of the lightning protection system and the integrity of the RAM. The lightning protection system has lightning receptors located at a tip region and one or two down-conductors disposed inside of the wind turbine blade for driving lightning current to ground. The RAM covers the entire wind turbine blade except the tip region and has at least a functional layer and a reflector layer connected to the one or two down conductors by means of auxiliary cables.

First claim

The invention claimed is:

1. A wind turbine blade ( 10 ) comprising a lightning protection system and shells ( 13 , 15 ) made of a composite material including Radar Absorbing Material; the lightning protection system comprising one or more lightning receptors ( 21 , 21 ′, 21 ″) and one or two down-conductors ( 23 , 23 ′) disposed inside of the wind turbine blade ( 10 ) for driving lightning current to ground; the Radar Absorbing Material comprising at least a functional layer ( 31 ) and a reflector layer ( 33 ) in a laminate of the shells ( 13 , 15 ); characterized in that:
the Radar Absorbing Material covers the entire wind turbine blade ( 10 ) except a tip region ( 12 ) located between an end of the blade and a cross section at a radius R having a length ranging from 80-90% of a length of the wind turbine blade;
the lightning receptors ( 21 , 21 ′, 21 ″) are located at the tip region ( 12 );
the reflector layer ( 33 ) of each of the shell ( 13 , 15 ) is connected to the one or two down conductors ( 23 , 23 ′) in at least two cross sections at radiuses R 1 , R 2 having a length ranging, respectively, from 0-20% and 80-90% of the length of the blade by means of auxiliary cables ( 29 , 29 ′).

2. The wind turbine blade ( 10 ) according to claim 1 , wherein the reflector layer ( 33 ) of each of the shell ( 13 , 15 ) is connected by two pairs of the auxiliary cables ( 29 , 29 ′) to two sections ( 24 ′, 24 ″) of one of said one or two down conductor ( 23 ), a first section ( 24 ′) of the two sections being arranged in the tip region of the wind turbine blade up to a connection between the first section ( 24 ′) and A first pair of the two pairs of the auxiliary cables ( 29 , 29 ′) and a second section ( 24 ″) of the two sections being arranged from a connection between the second section ( 24 ″) and a second pair of the two pairs of the auxiliary cables ( 29 , 29 ′) up to a ground connection.

3. The wind turbine blade ( 10 ) according to claim 1 , further comprising caps ( 19 ) made of carbon fiber composite material that are also connected to the auxiliary cables ( 29 , 29 ′).

4. The wind turbine blade ( 10 ) according to claim 3 , wherein the caps ( 19 ) are arranged in inner areas of the shells ( 13 , 15 ).

5. The wind turbine blade ( 10 ) according to claim 3 , wherein the caps ( 19 ) are arranged in blade beams.

6. The wind turbine blade according to claim 1 , wherein the reflector layer ( 33 ) of each of the shells ( 13 , 15 ) comprises a metallic mesh made of one of the following materials: copper, brass, aluminum, steel, and stainless steel.

7. The wind turbine blade according to claim 1 , wherein the reflector layer ( 33 ) of each of the shells ( 13 , 15 ) is a layer of carbon fiber composite material.

8. The wind turbine blade ( 10 ) according to claim 1 , wherein the reflector layer ( 33 ) of each of the shells ( 13 , 15 ) comprises first terminals ( 37 ) for a connection between the reflector layer ( 33 ) of each of the shells ( 13 , 15 ) and the auxiliary cables ( 29 , 29 ′).

9. The wind turbine blade ( 10 ) according to claim 8 , wherein the first terminals ( 37 ) are metallic brackets.

10. The wind turbine blade ( 10 ) according to claim 3 , wherein the caps ( 19 ) comprise second terminals ( 39 ) for a connection between the caps ( 19 ) and the auxiliary cables ( 29 , 29 ′).

11. The wind turbine blade ( 10 ) according to claim 10 , wherein the second terminals ( 39 ) are metallic brackets.

12. The wind turbine blade ( 10 ) according to claim 1 , wherein an external layer of the laminate of the shells ( 13 , 15 ) is the functional layer ( 31 ).

13. The wind turbine blade ( 10 ) according to claim 1 , wherein the functional layer ( 31 ) and the reflector layer ( 33 ) are embedded into layers ( 30 ) of glass fiber composite material.

14. The wind turbine blade ( 10 ) according to claim 13 , wherein the laminate of shells ( 13 , 15 ) comprises an additional functional layer ( 31 ′) embedded into the layers ( 30 ) of glass fiber composite material.

15. The wind turbine blade ( 10 ) according to claim 12 , wherein the distance between the functional layer ( 31 ) and the reflector layer ( 33 ) is in each of the shells ( 13 , 15 ) between 0.3-40 mm.

16. The wind turbine blade ( 10 ) according to claim 1 wherein the laminate of shells ( 13 , 15 ) further comprises a protective coating.

17. The wind turbine blade according to claim 1 , wherein the reflector layer ( 33 ) of each of the shells ( 13 , 15 ) comprises a metallic mesh made of one of the following materials: copper, brass, steel, and stainless steel.

Assignees

• Gamesa Innovation & Tech Sl
• Siemens Gamesa Renewable Energy Innovation & Technology SL

Inventors

• March Nomen Victor
• Madoz Zabalegui Juan

Classifications

• F05B2260/99

  Radar absorption · CPC title

• F03D1/0675 Primary

  of the blades · CPC title

• F03D80/30 Primary

  Lightning protection · CPC title

• F03D80/10

  Arrangements for warning air traffic · CPC title

• B32B2262/101

  Glass fibres · CPC title