EP-4741653-A2 - WIND TURBINE BLADE WITH A LIGHTNING PROTECTION SYSTEM

EP4741653A2EP 4741653 A2EP4741653 A2EP 4741653A2EP-4741653-A2

Abstract

Wind turbine blade comprising a lightning protection system, said lightning protection system comprising a first lightning receptor mounted near the tip of the blade and an electrical conductor electrically connecting the first lightning receptor and the base of the wind turbine blade. The lightning protection system further comprises a second lightning receptor which is integrated into the blade and where the electrical conductor comprises a first portion which is arranged between the second lightning receptor and the base of the blade, and where the first lightning receptor is surface mounted on the surface of the blade and in that the electrical conductor comprises a second portion which is surface mounted on the blade and is arranged between the first lightning receptor and the second lightning receptor. In this way, the first lightning receptor can be an aftermarket receptor which is surface mounted to the blade in a simple and inexpensive manner while the second lightning receptor is a legacy lightning receptor which was integrated with the blade during original manufacturing.

Inventors

HALL, ADAM
HALL, ALLEN
GAUDERN, Nicholas

Assignees

Pinnacle Lightning Protection,LLC
Power Curve ApS

Dates

Publication Date: 20260513
Application Date: 20230517

Claims (14)

Wind turbine blade comprising a lightning protection system, said lightning protection system comprising: a. a first lightning receptor mounted near the tip of the blade and b. an electrical conductor electrically connecting the first lightning receptor and the base of the wind turbine blade, characterized in that said lightning protection system further comprises a second lightning receptor which is integrated into the blade and where the electrical conductor comprises a first portion which is arranged between the second lightning receptor and the base of the blade, and where the first lightning receptor is surface mounted on the surface of the blade and in that the electrical conductor comprises a second portion which is surface mounted on the blade and is arranged between the first lightning receptor and the second lightning receptor.
Wind turbine blade according to claim 1, characterized in that the first portion of the electrical conductor is arranged on the inside of the blade.
Wind turbine blade according to claim 1 or 2, characterized in that the first portion of the electrical conductor is a wire running inside the blade and the second portion of the electrical conductor is conductive tape arranged on the surface of the blade.
Wind turbine blade according to any one of claims 1 to 3, characterized in that said wind turbine blade further comprises a first aerodynamic fence attached to the wind turbine blade between the first lightning receptor and the tip of the blade.
Wind turbine blade according to claim 4, characterized in that said first aerodynamic fence comprises a metal insert passing through a body portion of the first aerodynamic fence from a first side of the aerodynamic fence which faces the tip of the blade to a second side of the aerodynamic fence which faces the base of the blade, and wherein the second portion of the electrical conductor comprises a first part arranged between the first lightning receptor and the metal insert and a second part arranged between the metal insert and the second lightning receptor.
Wind turbine blade according to claim 4, characterized in that the second portion of the electrical conductor is arranged to pass around the first aerodynamic fence.
Wind turbine blade according to any one of claims 1 to 6, characterized in that the second portion of the electrical conductor comprises one or more segmented lightning diverter strips.
Wind turbine blade according to any one of claims 1 to 7, characterized in that said second portion of the electrical conductor and/or the first lightning receptor are attached to the blade via an adhesive.
Wind turbine blade according to any one of claims 1 to 8, characterized in that the wind turbine blade further comprises an aftermarket leading edge protection product to reduce surface abnormalities on the leading edge of the wind turbine blade.
Wind turbine blade according to claim 9, characterized in that the aftermarket leading edge protection product extends at least 30cm, at least 40cm or at least 50cm towards the base of the blade from the first lightning receptor.
Wind turbine blade according to claim 9 or 10, characterized in that the aftermarket leading edge protection product extends at least 30cm, at least 40cm or at least 50cm towards the tip of the blade from the aerodynamic fence.
Wind turbine blade according to any one of claims 9 to 11, characterized in that said leading edge protection product being arranged at least between the radial position of the first lightning receptor and the aerodynamic fence.
Wind turbine blade according to any one of claims 1 to 12, characterized in that said wind turbine blade further comprises a second aerodynamic fence located between the first lightning receptor and the base of the blade.
Wind turbine blade according to any one of claims 1 to 13, characterized in that a flow disturbance element is added to the surface of the blade inwardly of the first lightning receptor.

Description

FIELD OF THE INVENTION The current invention relates to a wind turbine blade comprising a lightning protection system, said lightning protection system comprising a first lightning receptor mounted near the tip of the blade and an electrical conductor electrically connecting the first lightning receptor and the base of the wind turbine blade. BACKGROUND OF THE INVENTION It is well known in the art of wind turbine blades, that a lightning strike to a blade can have serious consequences for the blade. In a worst case the entire blade can be destroyed which effectively renders the entire wind turbine useless and the entire blade needs to be replaced before the wind turbine can run again. In a less severe case, the wind turbine blade could survive, but be structurally damaged which can both make the blade perform poorly and also lead to reduced lifetime and higher risk of catastrophic failure of the blade. As such, many lightning protection systems have been proposed in the literature and many different systems have been implemented in practice. Most systems provide one or more lightning receptors in the form of one or more metal plates which are bolted to or embedded in the wind turbine blade itself. Typically the lightning receptors are mounted near the tip of the blade. Lightning receptors can be mounted to the suction side, to the pressure side or to both sides. Lightning receptors are then electrically connected to the base of the wind turbine blade via one or more electrical conductors running along the inside of the blade. The base of the blade is electrically connected to an electrical conductor running down the wind turbine tower to conduct lightning electrical energy to the ground. When lightning hits the blade, the concept is that the lighting is attracted to the lightning receptor on the blade and thereby hits the lightning receptor which allows the energy of the lightning strike to be absorbed by the lightning receptor and be conducted to the ground. In certain cases, multiple lightning receptors are attached in an array of lightning receptors around the tip area of the blade. Each of the lightning receptors is electrically connected to the base of the blade via an electrical conductor. In other cases, instead of embedding lightning receptors in the blade itself, the entire tip of the blade could be made of metal and form one big lightning receptor at the tip of the blade. In certain cases, the blade can have a metal mesh embedded within the laminate for the outer few metres of blade. In this case, multiple separate receptors could be linked to the mesh, and then the down conductor could be attached to the inboard end of the mesh. However, even though the concept of the lightning receptors seems to be clear, it is an observed fact in the industry that even with multiple lightning receptors mounted on the blade, lightning can still strike unprotected areas of the blade, causing serious structural damage or even catastrophic failures. SUMMARY OF THE INVENTION It is therefore a first aspect of the current invention to provide a lightning protection system for a wind turbine blade which is better at capturing the lightning strike at a lightning receptor. A second aspect of the current invention is to provide an improved lightning protection system which can be easily mounted on an existing wind turbine blade. A third aspect of the current invention is to provide an improved lightning protection system which does not incur significant costs. At least some of these aspects are provided at least in part by a wind turbine blade with a lightning protection system as mentioned in the introductory paragraph and further comprising a first aerodynamic fence attached to the wind turbine blade between the lightning receptor and the tip of the blade. In this way, the flow around the lighting receptor can be made smoother. While not being bound by this theory, it has been observed that wind turbine blades can have significant turbulent flows around the tip of the turbine blade. This is especially true for blades which have been active in the field for a while. During normal use and exposure to the weather and dirt/dust/bugs/etc., the leading edge of the blade becomes worn and more turbulent flow is created. In the prior art systems, the lightning receptors are mounted in this area of turbulent air. According to the current invention, by providing an aerodynamic fence outward of the lightning receptor to reduce the cross flow in the area of the lightning receptor, the air flow around the lightning receptor is made smoother and a lightning strike is thereby more likely to find the receptor. According to this specification, an aerodynamic fence is defined as an elongated fin, extending essentially vertically from the surface of the wind turbine blade, said fin being arranged essentially along a plane which is parallel to the chord of the blade at the location of the fin. In some embodiments, the phrase "essentially ve