The present subject matter relates generally to wind turbines, and more particularly to wind turbine rotor blades having a lightning protection system configured therewith.
Large commercial wind turbines are prone to lightning strikes and, in this regard, it is a common practice to provide the turbine blades with lightning receptors spaced along the longitudinal length of the blade so as to capture and conduct the strikes to ground. These receptors are typically connected to one or more cables that run internally within the blade and are in electrical conduction to ground through various components in the hub, nacelle, and tower. The conventional practice is to hand laminate or infuse the lightning protection cables in the suction or pressure side shell members during fabrication of the blade. This is a laborious and time intensive practice that adds significantly to the overall production costs of the blades.
Accordingly, a need exists for an improved method and system configuration for securing the lighting protection cables within the interior of a wind turbine blade.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In a particular embodiment, a wind turbine rotor blade has a root, a tip, and a pressure and suction side shell members that extend between the tip and root and defining an internal cavity. A plurality of any manner of suitable lightning receptors are configured along an exterior surface of either or both of the shell members. At least one lightning protection cable is disposed within the internal cavity of the blade, with the receptors configured in electrical conductive contact with the lightning protection cable. A plurality of cable attachment devices are disposed on and spaced apart along either or both of the shell members, depending on the number and location of the lightning protection cables. In a particular embodiment, the attachment devices have a base that is fixed to a respective shell member and a receiver configured on the base that supports the lighting protection cable. With this configuration, the plurality of attachment devices may support the lightning protection cable within the internal cavity without laminating or otherwise attaching the cables directly to the shell members.
The configuration of the attachment device base may vary. In one embodiment, the base is a post-like member with a flange at one end thereof that is affixed to the shell member, for example with mechanical fasteners, such as bolts. The flange may be bonded to the shell member in an alternative embodiment. In still another embodiment, the base has an end that is molded into the shell member during formation of the shell member.
The configuration of the receiver may also vary widely within the scope and spirit of the invention. For example, the receiver may be a loop member through which the lightning protection cable is disposed. The loop member may be a continuous closed member wherein the lightning protection cable is threaded through the loop member. Multiple loop members may be configured on a single base.
In an alternate embodiment, the loop member may include a hinged section that moves to an open position so that the lighting protection cable can be laid within the receiver prior to closing the hinged section.
The attachment devices are, in a particular embodiment, spaced apart and have the receivers at a sufficient height such that free lengths of the lightning protection cable between adjacent attachment devices are suspended above said shell member. However, in alternate embodiments, the receivers may be spaced just slightly above the shell member such that the free lengths of the lightning protection cable lie against the shell member between the adjacent attachment devices.
The present invention also encompasses various method embodiments for securing a lighting protection cable to a shell member of a wind turbine rotor blade. A plurality of attachment devices are fixed in a spaced-apart configuration to an interior surface of the shell member, with the attachment devices having a receiver at one end thereof. The lighting protection cable is engaged with the receivers such that the cable is intermittently supported by the plurality of receivers within the interior of the rotor blade.
The attachment devices may have a base, wherein the method includes fixing the base to the shell member by any suitable means, such as mechanical fasteners, bonding, molding, and the like. The base may have any desired height relative to the shell member surface.
In a particular embodiment, the attachment devices have a closed loop receiver, and the method includes threading the loop receivers onto the lightning protection cable prior to attaching the base to the shell member. In an alternate embodiment, the base is first affixed to the shell member, and the lightning protection cable is subsequently threaded through the loop receivers.
In still a further embodiment, the attachment devices have a base and a loop receiver with a hinged section that moves to an open position, and the method includes fixing the plurality of bases to the shell member in any desired pattern or spacing, laying the lighting protection cable into the open receivers, and closing the hinged sections of the loop receivers to secure the cable within the receivers.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
Referring to the drawings,
The rotor blades 16 may generally have any suitable length that enables the wind turbine 10 to function according to design criteria. The rotor blades 16 rotate the rotor hub 18 to enable kinetic energy to be transferred from the wind into usable mechanical energy, and subsequently, electrical energy. Specifically, the hub 18 may be rotatably coupled to an electric generator (not illustrated) positioned within the nacelle 14 for production of electrical energy.
Referring to
The lightning receptors 30 may be variously configured within the scope of the invention, and include any metal or metalized component (i.e., a metal screen, a metal rod or tip, and the like) mounted on the pressure or suction side shell members 26, 28 of the blade for the purpose of conducting lightning strikes to ground.
Still referring to
The lightening protection cables 32 are supported by a plurality of cable attachment devices 34 along the pressure or suction side shell members 26, 28. The attachment devices 34 are spaced apart along the length of the cable run so that the cable 32 is intermittently supported by the attachment devices 34 within the interior cavity 20 of the blade 16. Thus, the lightening protection cable 32 need not be laminated to, molded in, or otherwise permanently affixed to the shell members 26, 28.
Various embodiments of the cable attachment devices 34 are illustrated in
In the embodiment of
It should be readily appreciated that any manner of mechanical or adhesive/bonding method may be used to secure the base member 36 of the respective cable attachment devices 34 to the shell members at any desired location within the internal cavity 20 of the blade 16, and that the invention is not limited to any particular type of securement mechanism or method.
The receiver 43 may also vary widely within the scope and spirit of the invention. In the embodiments depicted in
In an alternate embodiment, the attachment devices 34 may be threaded onto the lightening protection cable 32, which is then laid out in the shell member 26, 28 along a desired cable run path. The attachments devices 34 may then be moved along the cable 32 to achieve a desired spacing of the attachment devices 34 prior to fixing the base members 36 to the respective shell member 26, 28. A mechanical fastening embodiment, such as the embodiment in
The embodiment of
Referring to
Referring to
It should be appreciated that the invention also encompasses any manner or configuration of wind turbine 10 having blades 16 utilizing any one of the aspects or embodiments of the invention described herein.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.