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Patent Issued for Wind turbine rotor blade lightning receptor arrangement (USPTO 11346328)

  • Jun 23, 2022
  • 45 views
Source: 
Energy Business Daily

2022 JUN 22 (NewsRx) -- By a News Reporter-Staff News Editor at Energy Business Daily -- Vestas Wind Systems A/S (Aarhus N, Denmark) has been issued patent number 11346328, according to news reporting originating out of Alexandria, Virginia, by NewsRx editors.

The patent’s inventors are Brilliant, Nathan A. (Arvada, CO, US), Sutton, Chris (Romsey, GB).

This patent was filed on August 21, 2018 and was published online on May 31, 2022.

From the background information supplied by the inventors, news correspondents obtained the following quote: “Wind turbines are vulnerable to being struck by lightning; sometimes on the tower, nacelle and the rotor hub, but most commonly on the rotor blades of the turbine. A lightning strike event has the potential to cause physical damage to the turbine blades and also electrical damage to the internal control systems of the wind turbine. Wind turbines are often installed in wide open spaces which makes lightning strikes a common occurrence. Accordingly, in recent years much effort has been made by wind turbine manufacturers to design wind turbines that are able to manage effectively the energy imparted to them during a lightning strike in order to avoid damage to the blade and the cost associated with turbine down-time during blade replacement.

“In general, lightning protection systems for wind turbine rotor blades are known. In one example, an electrically conductive lightning receptor element is arranged on an outer surface of the blade to receive a lighting strike. Since the receptor element is electrically conductive, lightning is more likely to attach to the receptor element in preference to the relatively non-conductive material of the blade. The receptor element is connected to a cable or ‘down conductor’ that extends inside the blade to the root and from there connects via an armature arrangement to a charge transfer route in or past the hub, nacelle and tower towards a ground potential. Such a lightning protection system therefore allows lightning to be channelled from the blade to a ground potential safely, thereby minimising the risk of damage. However, the discrete receptors are relatively complex to install during fabrication of the blade and they leave a significant portion of blade area exposed to a risk of lightning strike. In some lightning protection systems, the outer surface of the rotor blade may be supplied with a foil or mesh of an electrically conductive material to increase the likely area for the lightning to strike the rotor blade surface. The same or similar receptor elements as described above are electrically coupled to the electrically conductive material at the rotor blade surface and enable discharging to the ground.

“In WO 2015/055214 A1, a wind turbine rotor blade having a tip receptor arrangement is described. The receptor arrangement includes individual receptor bases that are connected to a down conductor within the wind turbine rotor blade and connected to an external surface of the blade by receptor elements that extend through the wind turbine rotor blade shell. When lightning strikes the rotor blade surface, the charge is transferred to the down conductor via the receptor elements and receptor bases.

“According to WO 2015/055214 A1, the receptor elements must be installed after the blade has been manufactured with the receptor arrangement in place. One of the problems associated with this method of fabricating the blade is that the exact positioning of each receptor base relative to the receptor element is very critical. To facilitate installation of the receptor elements, a plurality of holes are drilled through each blade shell and through the receptor bases. Receptor elements are then inserted into each hole to form an electrical connection between the surface of the blade and one of the receptor bases. If these holes do not properly align with the receptor bases, no or an unsatisfactory electrical connection between the receptor elements and the receptor bases will be established. Furthermore, if the down conductor is damaged during drilling, arcing or sparking may occur or a lightning strike may not be correctly conducted.

“It is an object of the invention to provide an improved lightning receptor arrangement for a wind turbine rotor blade that facilitates the desired connection between receptor elements and bases.”

Supplementing the background information on this patent, NewsRx reporters also obtained the inventors’ summary information for this patent: “According to the invention, this object is achieved by providing a wind turbine rotor blade lightning receptor arrangement, the receptor arrangement comprising an electrically conductive block and a shielding component. In use, the electrically conductive block forms an electrical bridge between a receptor element of a lightning protection system and a down conductor of the lightning protection system. The electrically conductive block comprises a first engagement surface for, in use, receiving the receptor element. The shielding component overlays a portion of the first engagement surface of the electrically conductive block, while leaving open an area for receiving the receptor element.

“The shielding component is particularly beneficial in installation of receptor elements into the blade. The receptor elements require holes drilled through a shell of the blade and the electrically conductive block at the conductive block. However, there are one or more areas of the electrically conductive block that should not be drilled through if a satisfactory connection between the receptor element and the electrically conductive block are to be formed. Thus, by covering the engagement surface of the electrically conductive block using the shielding component, the drill is unable to penetrate the electrically conductive block in these undesirable regions.

“In the context of this invention, the term “shielding” refers to mechanical shielding, such that the shielding component acts as an armour plate. The armour plate prevents a drill bit from penetrating the electrically conductive block where the armour plate is placed. It should be noted that in the context of this invention the term “shielding” does not refer to electromagnetic shielding.

“Advantageously, the shielding component not only protects the electrically conductive block, but also provides guidance to a drill operator should they strike the shielding component during an attempt to drill a hole. The operator can then adjust the drill position a little bit to ensure that the correct region of the electrically conductive block is drilled through.

“A critical link in the lightning discharge path is the connection between the electrically conductive block and the down connector. In order to avoid any damage to this connection during the drilling, the shielding component may further be arranged to at least partially overlay a connection between the electrically conductive block and the down conductor. For example, the electrically conductive block may comprise an internal bore for receiving the down conductor therein and the shielding component is aligned with the bore. In this way, it is ensured that the drilling will not damage the down conductor (if already connected when drilling) and that the receptor element will not enter the bore and/or damage the down conductor. Also, for a proper electrical connection between the receptor element and the electrically conductive block and to provide an as large as possible contact surface between the two, it is preferred that the full hole is in the electrically conductive block only.”

The claims supplied by the inventors are:

“1. A wind turbine rotor blade lightning receptor arrangement, the receptor arrangement comprising: an electrically conductive block that, in use, forms an electrical bridge between a receptor element of a lightning protection system and a down conductor of the lightning protection system, the electrically conductive block comprising a first engagement surface for, in use, receiving the receptor element, and a shielding component, overlaying a portion of the first engagement surface of the electrically conductive block, while leaving open an area for receiving the receptor element, wherein the shielding component is in the form of an armour plate attached to the first engagement surface and arranged such that, in use, the receptor element does not extend through the armour plate, wherein the shielding component is further arranged to at least partially overlay a connection between the electrically conductive block and the down conductor, and wherein the electrically conductive block comprises an internal bore for receiving the down conductor therein, and the shielding component is aligned with the internal bore.

“2. The wind turbine rotor blade lightning receptor arrangement of claim 1, wherein the electrically conductive block comprises a second engagement surface, opposite the first engagement surface, and wherein the shielding component is further arranged to overlay a portion of the second engagement surface.

“3. The wind turbine rotor blade lightning receptor arrangement of claim 1, wherein the shielding component is configured to overlay an edge region of at least the first engagement surface.

“4. The wind turbine rotor blade lightning receptor arrangement of claim 3, wherein the first engagement surface comprises a central region for receiving the receptor element and a plurality of edge regions surrounding the central region, and wherein the shielding component is disposed in the edge regions only.

“5. The wind turbine rotor blade lightning receptor arrangement of claim 1, wherein the electrically conductive block and the shielding component are together encapsulated in an electrically insulative material.

“6. The wind turbine rotor blade lightning receptor arrangement of claim 1, wherein the shielding component is made of a non-conductive material.

“7. The wind turbine rotor blade lightning receptor arrangement of claim 1, wherein the shielding component is made of a material having a hardness of at least 1200 kgf/mm2.

“8. The wind turbine rotor blade lightning receptor arrangement of claim 1, wherein the shielding component is made of a material having a hardness of at most 2000 kgf/mm2.

“9. The wind turbine rotor blade lightning receptor arrangement of claim 1, wherein the shielding component is made of a ceramic.

“10. The wind turbine rotor blade lightning receptor arrangement of claim 1, wherein the shielding component is made of aluminum silicate.

“11. A wind turbine rotor blade, comprising: a blade shell defining an outer surface and an interior; a lightning protection system including a down conductor extending along the interior of the blade shell and at least one receptor arrangement, the at least one receptor arrangement comprising: a receptor element extending from the outer surface to the interior of the blade shell; an electrically conductive block in the interior of the blade shell and including a first engagement surface that receives the receptor element; and a shielding component, overlaying a portion of the first engagement surface of the electrically conductive block, while leaving open an area for receiving the receptor element, wherein the electrical conductive block forms an electrical bridge between the receptor element and the down conductor, wherein the shielding component is in the form of an armour plate attached to the first engagement surface and arranged such that the receptor element does not extend through the armour plate, wherein the shielding component is further arranged to at least partially overlay a connection between the electrically conductive block and the down conductor, and wherein the electrically conductive block comprises an internal bore for receiving the down conductor therein, and the shielding component is aligned with the internal bore.

“12. A wind turbine comprising the wind turbine rotor blade according to claim 11.”

For the URL and additional information on this patent, see: Brilliant, Nathan A. Wind turbine rotor blade lightning receptor arrangement. U.S. Patent Number 11346328, filed August 21, 2018, and published online on May 31, 2022. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=11346328.PN.&OS=PN/11346328RS=PN/11346328

 

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