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Patent Issued for Method Of Testing Wind-Turbine Receptor (USPTO 10,401,414)

Source: 
Defense & Aerospace Daily

2019 SEP 17 (NewsRx) -- By a News Reporter-Staff News Editor at Defense & Aerospace Daily -- According to news reporting originating from Alexandria, Virginia, by NewsRx journalists, a patent by the inventors Matsushita, Takatoshi (Tokyo, Japan); Ota, Keisuke (Tokyo, Japan); Hasegawa, Osamu (Tokyo, Japan); Imaoka, Kengo (Tokyo, Japan); Fukami, Koji (Tokyo, Japan), filed on February 8, 2017, was published online on September 16, 2019.

The assignee for this patent, patent number 10,401,414, is Mitsubishi Heavy Industries Ltd. (Tokyo, Japan).

Reporters obtained the following quote from the background information supplied by the inventors: “To protect a wind turbine blade from lightning strikes, normally, a receptor (metal lightning-receiving part) is mounted to a blade surface to receive lightning strikes. A receptor is, for instance, connected to an earth wire via a down-conductor so as to guide lightning current received by the receptor to the earth wire.

“For instance, Patent Document 1 discloses a wind turbine power generating apparatus including a plurality of receptors disposed on the surface of a blade body so as to be exposed, and a down-conductor disposed inside the blade body and connected electrically to the receptors.”

In addition to obtaining background information on this patent, NewsRx editors also obtained the inventors’ summary information for this patent: “Meanwhile, if electric connection between a receptor disposed on the surface of a wind turbine blade and an earth wire is not secure, there is a risk of occurrence of sparks upon receipt of lightning by the receptor, which may cause damage to the wind turbine blade. In view of this, one may consider performing an electrical continuity test on a receptor of a wind turbine blade, but it is not easy to perform an electric continuity test on a receptor while a wind turbine blade is mounted to a hub.

“An object of at least some embodiments of the present invention is to provide a method of testing a wind-turbine receptor whereby it is possible to perform an electric continuity test simply on a receptor of a wind turbine blade.

“(1) A method of testing a receptor of a wind turbine, according to at least some embodiments of the present invention, comprises: a step of moving an unmanned aerial vehicle (UAV) close to the receptor of a wind turbine blade mounted to a hub of the wind turbine, and performing an electric continuity test on the receptor.

“According to the above method (1), using a UAV makes it easier to approach the receptor of the wind turbine blade mounted to the hub, and to perform an electrical continuity test on the receptor simply. Thus, it is possible to shorten the testing time, as well as to reduce the testing costs, as compared to an electric continuity test using a vehicle for work at height

“(2) In some embodiments, the above method (1) further comprises a step of forming an electric continuity test circuit including the receptor by using the UAV. The step of performing the electric continuity test includes applying a voltage to the electric continuity test circuit.

“According to the above method (2), the electric continuity test circuit including the receptor can be readily formed by using the UAV, and thereby it is possible to improve the efficiency of continuity test works for the receptor.

“(3) In some embodiments, in the above method (2), the receptor is disposed on a tip portion of the wind turbine blade, and the method further comprises a step of engaging the tip portion of the wind turbine blade with a position-determining portion disposed on the UAV to retain a relative position of the UAV with respect to the receptor.

“According to the above method (3), the tip portion of the wind turbine blade is in engagement with the position-determining portion of the UAV to retain the relative position of the UAV with respect to the receptor. Accordingly, it is possible to perform works for forming the electric continuity test circuit including the receptor efficiently by using the UAV.

“(4) In some embodiments, in the above method (3), the position-determining portion includes at least one of: a cap engageable with the tip portion of the wind turbine blade; a clamp configured to nip the tip portion of the wind turbine blade in response to operation of a link mechanism by being pressed against the tip portion of the wind turbine blade; or a shaping portion which is deformable so as to follow an outer shape of the tip portion by being pressed against the tip portion of the wind turbine blade.

“According to the above method (4), making use of the position determining portion including at least one of: the cap to be in engagement with the tip portion of the wind turbine blade; the clamp configured to nip the tip portion of the wind turbine blade; or the shaping portion being deformable so as to follow the outer shape of the tip portion, makes it possible to retain the relative position of the UAV with respect to the receptor reliably. Accordingly, it is possible to perform works for forming the electric continuity test circuit including the receptor efficiently by using the UAV.

“(5) In some embodiments, in any one of the above methods (2) to (4), at least a part of the receptor, or at least a part of a portion of the wind turbine blade around the receptor is formed by a magnetic element. The step of forming an electric continuity test circuit includes connecting a wire to the receptor while applying a magnetic force generated by a magnetic-force generating part disposed on the UAV to the magnetic element.

“According to the above method (5), at least a part of the receptor or a portion of the wind turbine blade around the receptor is formed by a magnetic element, and a magnetic force generated by the magnetic-force generating part is applied to the magnetic element, which makes it possible to improve the efficiency of works for connecting wire to the receptor by using the UAV (works for forming an electric continuity test circuit).

“(6) In some embodiments, in the above method (5), the magnetic-force generating part is configured to be rotatable relative to a body of the UAV, about two axes orthogonal to an upward-and-downward direction of the UAV.

“According to the above method (6), the magnetic-force generating part is configured to be rotatable with respect to the body of the UAV, and thus it is possible to attract the magnetic-force generating part toward the magnetic element reliably regardless of the relative attitude of the UAV with respect to the magnetic element (receptor or a peripheral portion thereof), which makes it possible to further improve the efficiency of works for connecting wire to the receptor by the UAV.

“(7) In some embodiments, in any one of the above methods (2) to (6), the UAV includes a shock absorbing member including a conductive portion at least on a surface side of the shock absorbing member. The step of forming the electric continuity test circuit includes forming the electric continuity test circuit by moving the UAV to press the shock absorbing member against the wind turbine blade and connect a wire to the receptor via the conductive portion of the shock absorbing member.

“According to the above method (7), it is possible to connect wire to the receptor via the conductive portion of the shock absorbing member while mitigating shock due to contact between the UAV and the wind turbine blade with the shock absorbing member.

“(8) In some embodiments, in any one of the above methods (2) to (7), the UAV includes a container storing a conductive element in a liquid form, a gel form or a powder form. The step of forming the electric continuity test circuit includes forming the electric continuity test circuit by moving the UAV to cause a portion of the wind turbine blade including the receptor to enter the container and connect a wire to the receptor via the conductive element.

“According to the above method (8), it is possible to connect wire to the receptor via the conductive element efficiently, by operating the UAV so that a tip of the wind turbine blade enters the container storing the conductive element.

“(9) In some embodiments, in any one of the above methods (2) to (8), the UAV includes a reel provided with a wire wound around the reel. The step of forming the electric continuity test circuit includes moving the UAV close to the wind turbine blade to connect the wire to the receptor, and unwinding the wire from the reel.

“According to the above method (9), it is possible to move the UAV close to the wind turbine blade while the wire is wound around the reel, and thus it is possible to prevent a decrease in the attitude stability of the UAV due to a drag that the wire receives if the wire is suspended from the UAV while the UAV moves upward.

“(10) In some embodiments, in the above method (9), the step of forming the electric continuity test circuit includes attaching the wire of the reel to the receptor by using the UAV, detaching the UAV from the reel, and allowing the reel to unreel and move downward.

“According to the above method (10), if the reel is detached from the UAV to unreel and move down after an end of the wire is attached to the receptor, it is possible to form the electric continuity test circuit readily by a worker below the wind turbine blade recovering the other end of the wire and connecting the wire to an earth terminal.

“(11) In some embodiments, in any one of the above methods (2) to (9), the step of forming the electric continuity test circuit includes connecting the receptor to an earth wire via a wire suspended from the UAV. The method further comprises a step of detaching the wire from the UAV, after performing the electric continuity test on the receptor.

“According to the above method (11), it is possible to form the electric continuity test circuit readily by connecting the receptor to the earth wire via the wire suspended from the UAV. Furthermore, by detaching the wire from the UAV after completion of an electric continuity test, it is possible to improve the attitude stability of the UAV during downward movement of the UAV upon recovery of the UAV.

“(12) In some embodiments, in the above method (2), the step of forming the electric continuity test circuit includes suspending a conductive cloth member which constitutes a part of the electric continuity test circuit from at least one of the UAV, moving the at least one UAV toward the wind turbine blade from an upwind side, and pressing the conductive cloth member against a portion of the wind turbine blade including the receptor by making use of wind.

“According to the above method (12), it is possible to form the electric continuity test circuit readily by moving the UAV suspending the conductive cloth member to the wind turbine blade from the upwind side, and pressing the conductive cloth member against the receptor by making use of wind.

“(13) In some embodiments, the above method (2) further comprises a step of injecting a conductive liquid to the receptor from the UAV. The step of forming the electric continuity test circuit includes connecting the receptor to the wire via a liquid flow of the conductive liquid.

“According to the above method (13), it is possible to form the electric continuity test circuit readily by electrically connecting the receptor to the wire via a liquid flow of the conductive liquid.

“(14) In some embodiments, in any one of the above methods (1) to (13), the method further comprises a step of surrounding the UAV with a wind shield member mounted to at least one auxiliary UAV.

“According to the above method (14), the UAV is covered with the windshield member mounted to the at least one auxiliary UAV, and thus it is possible to maintain the attitude stability of the UAV without being affected by wind, while the UAV approaches the receptor, or while the UAV is in a standby state near the receptor.

“(15) In some embodiments, in the above method (1), the step of performing the electric continuity test includes changing a magnetic field applied to the receptor by using the UAV and detecting an induction current generated in a circuit from the receptor to an earth wire.

“According to the above method (15), changing a magnetic field applied to the receptor makes it possible to generate an induction current in a circuit (e.g. the down-conductor) from the receptor to the earth wire. Thus, it is possible to confirm electrical connection between the receptor and the earth wire with a simplified method of detecting an induction current generated in a circuit from the receptor to the earth wire.

“According to some embodiments of the present invention, using the UAV to test the receptor of the wind turbine makes it easier to approach the receptor of the wind turbine blade mounted to the hub, and to perform an electric continuity test on the receptor simply. Thus, it is possible to shorten the testing time, as well as to reduce the testing costs, as compared to an electric continuity test using a vehicle for work at height.”

The claims supplied by the inventors are:

“The invention claimed is:

“1. A method of testing a receptor of a wind turbine, the method comprising: a step of moving an unmanned aerial vehicle (UAV) close to the receptor of a wind turbine blade mounted to a hub of the wind turbine, and performing an electric continuity test on the receptor; and a step of forming an electric continuity test circuit including the receptor by using the UAV, wherein the step of performing the electric continuity test includes applying a voltage to the electric continuity test circuit, wherein the UAV includes a reel provided with a wire wound around the reel, and wherein the step of forming the electric continuity test circuit includes moving the UAV close to the wind turbine blade to connect the wire to the receptor, and unwinding the wire from the reel to form the electric continuity test a part of which is formed by the unwound wire.

“2. The method of testing a receptor of a wind turbine according to claim 1, wherein the receptor is disposed on a tip portion of the wind turbine blade, and wherein the method further comprises a step of engaging the tip portion of the wind turbine blade with a position-determining portion disposed on the UAV to retain a relative position of the UAV with respect to the receptor.

“3. The method of testing a receptor of a wind turbine according to claim 1, wherein at least a part of the receptor, or at least a part of a portion of the wind turbine blade around the receptor is formed by a magnetic element, and wherein the step of forming the electric continuity test circuit includes connecting the wire to the receptor while applying a magnetic force generated by a magnetic-force generating part disposed on the UAV to the magnetic element.

“4. The method of testing a receptor of a wind turbine according to claim 3, wherein the magnetic-force generating part is configured to be rotatable relative to a body of the UAV, about two axes orthogonal to an upward-and-downward direction of the UAV.

“5. The method of testing a receptor of a wind turbine according to claim 1, wherein the UAV includes a container storing a conductive element in a liquid form, a gel form or a powder form, and wherein the step of forming the electric continuity test circuit includes forming the electric continuity test circuit by moving the UAV to cause a portion of the wind turbine blade including the receptor to enter the container and connect a wire to the receptor via the conductive element.

“6. The method of testing a receptor of a wind turbine according to claim 1, wherein the step of forming the electric continuity test circuit includes attaching the wire of the reel to the receptor by using the UAV, detaching the UAV from the reel, and allowing the reel to unreel and move downward.

“7. The method of testing a receptor of a wind turbine according to claim 1, wherein the step of forming the electric continuity test circuit includes connecting the receptor to an earth wire via a wire suspended from the UAV, and wherein the method further comprises a step of detaching the wire from the UAV, after performing the electric continuity test on the receptor.

“8. The method of testing a receptor of a wind turbine according to claim 1, further comprising a step of injecting a conductive liquid to the receptor from the UAV, wherein the step of forming the electric continuity test circuit includes connecting the receptor to the wire via a liquid flow of the conductive liquid.

“9. The method of testing a receptor of a wind turbine according to claim 1, further comprising a step of surrounding the UAV with a wind shield member mounted to at least one auxiliary UAV.

“10. The method of testing a receptor of a wind turbine according to claim 1, wherein the step of performing the electric continuity test includes changing a magnetic field applied to the receptor by using the UAV and detecting an induction current generated in a circuit from the receptor to an earth wire.

“11. A method of testing a receptor of a wind turbine, comprising: a step of moving an unmanned aerial vehicle (UAV) close to the receptor of a wind turbine blade mounted to a hub of the wind turbine, and performing an electric continuity test on the receptor; and a step of forming an electric continuity test circuit including the receptor by using the UAV, wherein the step of performing the electric continuity test includes applying a voltage to the electric continuity test circuit, wherein the receptor is disposed on a tip portion of the wind turbine blade, wherein the method further comprises a step of engaging the tip portion of the wind turbine blade with a position-determining portion disposed on the UAV to retain a relative position of the UAV with respect to the receptor, and wherein the position-determining portion includes at least one of: a cap engageable with the tip portion of the wind turbine blade; a clamp configured to nip the tip portion of the wind turbine blade in response to operation of a link mechanism by being pressed against the tip portion of the wind turbine blade; or a shaping portion which is deformable so as to follow an outer shape of the tip portion by being pressed against the tip portion of the wind turbine blade.

“12. A method of testing a receptor of a wind turbine, comprising: a step of moving an unmanned aerial vehicle (UAV) close to the receptor of a wind turbine blade mounted to a hub of the wind turbine, and performing an electric continuity test on the receptor; and a step of forming an electric continuity test circuit including the receptor by using the UAV, wherein the step of performing the electric continuity test includes applying a voltage to the electric continuity test circuit, wherein the UAV includes a shock absorbing member including a conductive portion at least on a surface side of the shock absorbing member, and wherein the step of forming the electric continuity test circuit includes forming the electric continuity test circuit by moving the UAV to press the shock absorbing member against the wind turbine blade and connect a wire to the receptor via the conductive portion of the shock absorbing member.

“13. A method of testing a receptor of a wind turbine, comprising: a step of moving an unmanned aerial vehicle (UAV) close to the receptor of a wind turbine blade mounted to a hub of the wind turbine, and performing an electric continuity test on the receptor; and a step of forming an electric continuity test circuit including the receptor by using the UAV, wherein the step of performing the electric continuity test includes applying a voltage to the electric continuity test circuit, and wherein the step of forming the electric continuity test circuit includes suspending a conductive cloth member which constitutes a part of the electric continuity test circuit from at least one of the UAV, moving the at least one UAV toward the wind turbine blade from an upwind side, and pressing the conductive cloth member against a portion of the wind turbine blade including the receptor by making use of wind.”

For more information, see this patent: Matsushita, Takatoshi; Ota, Keisuke; Hasegawa, Osamu; Imaoka, Kengo; Fukami, Koji. Method Of Testing Wind-Turbine Receptor. U.S. Patent Number 10,401,414, filed February 8, 2017, and published online on September 16, 2019. 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=10,401,414.PN.&OS=PN/10,401,414RS=PN/10,401,414

 

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