Spar cap, wind turbine blade, wind turbine and method for manufacturing a spar cap

Abstract

A spar cap for a wind turbine blade of a wind turbine, the spar cap including at least one elongated beam is provided. The spar cap includes at least one electrically isolating material cover and at least one electrically conductive material cover, wherein an entire circumference of the beam is enclosed by at least one electrically isolating material cover and the entire circumference of the at least one electrically isolating material cover is enclosed by at least one electrically conductive material cover, whereby the electrically conductive material cover has at least one electrical interface for electrically connecting it to a down conductor of the wind turbine blade.

Claims

1. A spar cap for a wind turbine blade of a wind turbine, the spar cap comprising at least one elongated beam, wherein, the spar cap includes at least one electrically isolating material cover and at least one electrically conductive material cover, wherein an entire circumference of the beam is enclosed by at least one electrically isolating material cover and the entire circumference of the at least one electrically isolating material cover is enclosed by at least one electrically conductive material cover, whereby the electrically conductive material cover has at least one electrical interface for electrically connecting it to a down conductor of the wind turbine blade.

2. The spar cap according to claim 1, wherein the electrically isolating material cover and/or the electrically conductive material cover are arranged along at least 80% of a length of the beam, at least along the entire length of the beam and beyond the entire length of the beam, so that the electrically conductive material cover extends beyond at least one longitudinal end of the beam.

3. The spar cap according to claim 1, wherein, the electrically isolating material cover comprises glass fibers.

4. The spar cap according to claim 1, wherein, the electrically conductive material cover is a metal mesh.

5. The spar cap according to claim 1, wherein, the at least one beam comprises carbon fiber-reinforced plastic.

6. The spar cap according to claim 1, wherein, the at least one beam is precasted together with at least one of the isolating material cover and the electrically conductive material cover.

7. A wind turbine blade for a wind turbine, the wind turbine blade having a shell, a down conductor and a spar attached to the shell, wherein the spar comprises two spar caps and a spar web connecting the two spar caps with one another, whereby at least one of the spar caps is according to claim 1.

8. The wind turbine blade according to claim 7, wherein, the at least one electrical interface of the electrically conductive material cover of the at least one spar cap is connected to the down conductor by at least one metal conductor.

9. The wind turbine blade according to claim 8, wherein, at least one of the at least one metal conductor is a flexible metal cable.

10. The wind turbine blade according to claim 8, wherein, at least one of the at least one metal conductor is provided at or within a distance of 5% of the length of the beam from a root of the wind turbine blade and/or at least one of the at least one metal conductor is provided at or within a distance of 5% of the length of the beam from a tip of the wind turbine blade.

11. The wind turbine blade according to claim 7, wherein, the down conductor is attached to the spar web, along at least 80% of the length of the spar web.

12. The wind turbine comprising at least one wind turbine blade according to claim 7.

13. A method of manufacturing a spar cap for a wind turbine blade of a wind turbine, the spar cap comprising at least one elongated beam, the method comprises the steps of: (a) enclosing an entire circumference of the beam by at least one electrically isolating material cover, (b) enclosing an entire circumference of the at least one electrically isolating material cover by at least one electrically conductive material cover, and (c) providing the electrically conductive material cover with at least one electrical interface for electrically connecting it to a down conductor of the wind turbine blade.

Description

BRIEF DESCRIPTION

(1) Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

(2) FIG. 1 a side view on an embodiment of a wind turbine according to embodiments of the invention;

(3) FIG. 2 a side sectional view along a transversal plane of a wind turbine blade of the wind turbine of FIG. 1;

(4) FIG. 3 a side perspective view on a beam of the wind turbine blade of FIG. 2; and

(5) FIG. 4 a side perspective view on an arrangement of a middle portion of the beam of FIG. 3 in the wind turbine blade of FIG. 2.

DETAILED DESCRIPTION

(6) FIG. 1 is a side view on an embodiment of a wind turbine 1 according to embodiments of the invention. The wind turbine 1 is provided with three wind turbine blades 10.1, 10.2, 10.3 attached to a hub 4 of the wind turbine 1, which is connected to a nacelle 3 of the wind turbine 1, the nacelle 3 being supported on a mast 2 of the wind turbine 1. Each of the wind turbine blades 10.1, 10.2, 10.3 has a root and a tip, wherein root 13.1 and tip 14.1 of the wind turbine blade 10 are denominated in FIG. 1.

(7) FIG. 2 is a side sectional view along the transversal plane of line X-X depicted in FIG. 1 of the wind turbine blade 10.1 of the wind turbine 1 of FIG. 1. The wind turbine blade 10 has a longitudinal extension in a longitudinal direction L, a width extension in a width direction W and a height extension in a height direction H. The wind turbine blade 10 further has a trailing edge 11 and a leading edge 12. The wind turbine blade 10 comprises a shell 20 and a spar 30 attached to the shell 20. The spar 30 comprises two spar caps 40.1, 40.2, each of which has a beam 41.1, 41.2. The two spar caps 40.1, 40.2 face each other and are connected to one another by means of a spar web 50, in this particular embodiment. However, other arrangements of the spar 30, such as an H-beam or X-beam type spar 30 are possible.

(8) FIG. 3 is a side perspective view on the beam 41.2 of the wind turbine blade 10 of FIG. 2. The beam 41.2 is elongated in the longitudinal direction L. The beam 41.2 is tapered towards its longitudinal ends, in particular root and tip of the beam 41.2, which however, is not shown in FIG. 3. The beam 41.2 is made from carbon fiber-reinforced plastic. In particular, the beam comprises multiple pultruded strips 43 made from carbon fiber-reinforced plastic, of which the strips 43.1, 43.2, 43.3, 43.4, 43.5 are depicted. The multiple stacks 42 are arranged as three adjacent stacks 42.1, 42.2, 42.3, each of which comprises five strips 43 stacked on top of one another. An electrically isolating material cover 44 is wrapped around an entire circumference of the beam 41.2, the circumference running transverse to a longitudinal direction L of the beam 41.2. An electrically conductive material cover 45 is wrapped around the entire circumference of the electrically isolating material cover 44 wrapped around the at least one beam 41.2. Ends of the electrically isolating material cover 44 are overlapping one another and in particular connected to one another. Ends of the electrically conductive material cover 45 are also overlapping one another and in particular connected to one another. The electrically isolating material cover 44 and the electrically conductive material cover 45 are arranged along an entire length L41 of the beam 41.2, the length L41 of the beam 41.2 being measured in the longitudinal direction L. Preferably the electrically isolating material cover 44 and/or the electrically conductive material cover 45 extend beyond opposite longitudinal ends of the beam 41.2.

(9) A first metal conductor 46.1 is provided at the root 13 of the beam 41.2, i.e. the wind turbine blade 10, and a second metal conductor 46.2 is provided at the tip 14 of the beam 41.2, i.e. the wind turbine blade 10. The first and second metal conductors 46.1, 46.2 are arranged transverse to the longitudinal direction L.

(10) FIG. 4 is a side perspective view on an arrangement of a middle portion of the beam 41.2 of FIG. 3 in the wind turbine blade 10 of FIG. 2. Therein, an inner part of the shell 20 is connected to the beam 41.2 and the spar web 50. The electrically conductive material cover 45 is connected to a down conductor 51 by means of a third metal conductor 46.3, with the first metal conductor 46.1 and second metal conductor 46.2 not being shown as FIG. 4 only shows a middle portion of the beam 41.2. The third metal conductor 46.3 is an equipotential connection to equipotentialize the voltage built up between the down conductor 51 and the electrically conductive material cover 45. The metal conductor 46.3 is designed as a flexible metal cable in this particular embodiment. The metal conductor 46.3 is further made from copper in this particular embodiment.

(11) A down conductor 51 of the wind turbine blade 10 is attached along 80% to 100% of the entire length of the spar web 50. The down conductor 51 is electrically connected to the electrically conductive material cover 45 by means of the third metal conductor 46.3. The third metal conductor 46.3 is led through an opening in the shell 20, in particular the inner part of the shell 20.

(12) Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

(13) For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements. The mention of a “unit” or a “module” does not preclude the use of more than one unit or module.