A BLADE FOR A ROTOR OF A WIND TURBINE COMPRISING INTERNALLY A CONTINOUS CABLE ARRANGEMENT INTENDED TO MEASURE CONDUCTIVITY

OBJECT OF THE INVENTION

The present subject matter is encompassed within the field of wind turbines blades and, more particularly, relates to a blade for a rotor of a wind turbine intended to measure con ductivity for blade lightning protection thereof. The object of the present invention is a wind turbine blade which ease reparation and conductivity level measurement during preven tive and/or corrective maintenance by means of an inwardly continuous cable arrangement extending therebetween the blade root and the blade tip closing an electrical loop so that conductivity can be measured.

BACKGROUND OF THE INVENTION

Blade Lightning Protection System (LPS) and check of conduc tivity along lifetime is a very expensive issue to be taken into account for both the preventive and corrective actions related to LPS incident. It is also a requirement from IEC standard and Certification approval as well as liabilities for blade lightning incidents.

Some wind turbines blades intended for blade lightning pro tections are known in the state of the art. However, all of said known blades require external blade connections through wires from blade root to blade tip receptor to proof that the conductivity levels are within the allowable tolerances. This require a very costly operation in term of lack of production while the measurement is taking place as well as high level qualified technicians to perform blade external rope inspec tion just to place the wire in the right location. Even the on-going development of drone assisted inspection requires a highly specific equipment to close the loop and measure conductivity level.

DESCRIPTION OF THE INVENTION

A wind turbine blade is disclosed herein with which it has been found that at least the above disadvantages relating to the prior art solutions are mitigated.

More in particular, there is provided A blade for a rotor of a wind turbine comprising inwardly a continuous cable ar rangement intended to measure conductivity for blade light ning protection, wherein said blade comprises a blade root, a blade tip, a leading edge and a trailing edge with a chord extending therebetween, characterized in that the cable ar rangement comprises an upper portion and a lower portion ex tending there between the blade root and the blade tip, said lower portion electrically in contact with the upper portion closing an electrical loop thereof, and wherein the blade further comprises an electrical connector element located at the blade root and electrically in contact with the upper portion and the lower portion, said electrical connector el ement protruding exteriorly on the blade root so that conduc tivity of the blade can be measured.

The lower portion of the cable arrangement may comprise a plurality of nodes near the blade tip extending near the blade tip in the region towards the trailing edge, so that conductivity can be more accurately measured the trailing edge region on the blade tip.

According to any of the previous embodiments, the upper por tion of the cable arrangement may also comprise a plurality of nodes near the blade tip, extending towards the leading edge so that conductivity can be more accurately measured the leading edge region on the blade tip. Alternatively, the upper portion of the cable arrangement may comprise a concave configuration near the blade tip, extend ing towards the leading edge.

Similarly, the lower portion of the cable arrangement may comprise a convex configuration near the blade tip, extending towards the trailing edge.

DESCRIPTION OF THE DRAWINGS

To complement the description being made and in order to aid towards a better understanding of the characteristics of the invention, in accordance with a preferred example of practical embodiment thereof, a set of drawings is attached as an integral part of said description wherein, with illustrative and non-limiting character, the following has been represented:

Figure 1.- Shows a front view of a blade cable arrangement to measure conductivity according to an embodiment known in the prior art.

Figure 2.- Shows a front view of a preferred embodiment of the blade according to the invention where it is shown the cable arrangement comprising a upper portion and a lower portion electrically in contact with each other closing an electrical loop, and both connected to an electrical element protruding at the root.

PREFERRED EMBODIMENT OF THE INVENTION

What follows is a detailed description, with the help of the attached figures 1-3 referenced above, a preferred embodiment of the invention and prior art solutions.

In Figure 1, it is shown a solution known in the prior art, wherein the blade inwardly comprises a cable arrangement (2) intended to measure conductivity for blade lightning protec- tion, wherein the cable arrangement (2) comprises a upper portion (4) extending therebetween the blade root (8) and the blade tip (9) and electrically in contact with an electrical connector element (7).

Figure 2 illustrates a preferred embodiment of the present invention, wherein it is shown a blade for a rotor of a wind turbine comprising inwardly a continuous cable arrangement (2) intended to measure conductivity for blade lightning pro- tection, wherein said blade (1) comprises a blade root (8), a blade tip (9), a leading edge (10) and a trailing edge (11) with a chord extending therebetween.

Furthermore, Figure 2 illustrates a cable arrangement (2) comprising an upper portion (4) and a lower portion (3) ex tending there between the blade root (8) and the blade tip (9), said lower portion (3) electrically in contact with the upper portion (2) closing an electrical loop thereof. Figure 2 further illustrates an electrical connector element (7) located at the blade root (8) and electrically in contact with the upper portion (3) and the lower portion (3) wherein said electrical connector element (7) protrudes exteriorly on the blade root (8) so that conductivity of the blade (1) can be measured.

In a preferred embodiment shown in Figure 2 both the upper portion (4) and the lower portion (3) of the cable arrange ment (2) comprise nodes (5,6).