Patent Application
20120136630
The invention described herein relates generally to a method and system for inspecting a wind turbine. More specifically, the invention relates to a method and system employing a remotely operated aerial platform for inspecting a wind turbine.
Wind turbines need to be inspected on a regular basis to keep them operating reliably and effectively. However, damage invariably occurs to the wind turbine either from external effects (e.g., lightning, wind, rain, hail, etc.) or from general wear and tear leading to fatigue of various components.
The outside of the tower is difficult to inspect, and large cranes are often needed to provide access for close inspection of the various components, such as the blades. A technician can manually climb the tower and rappel down, but this is a time consuming, labor intensive and hazardous activity. The inside of the wind turbine also needs to be inspected, and a technician must climb the tower and enter the nacelle. This is also a time consuming and labor intensive activity. In addition, there are often limits placed on the number of climbs any one technician can perform per day. This can be particularly problematic when a wind farm has a large number of wind turbines, and each wind turbine needs to be inspected. Further, wind turbines typically must be shut down when personnel are inside the wind turbine, and this reduces the production capability of the wind turbine currently undergoing an inspection.
Inspection of offshore wind turbines is also challenging mainly due to accessibility of the turbine. Offshore wind turbines can be subjected to a harsher operation environment and regular inspection is important for maintaining the availability and health of the wind turbine.
In an aspect of the present invention, a method is provided for inspecting a wind turbine. The method includes the steps of providing at least one remotely operated aerial platform (ROAP), providing at least one non-destructive evaluation (NDE) device attached to the remotely operated aerial platform, and providing at least one distance measuring system attached to the remotely operated aerial platform. The distance measuring system is used for determining the distance between the remotely operated aerial platform and at least a portion of the wind turbine. The method also includes positioning the at least one remotely operated aerial platform so that the non-destructive evaluation device captures data used for inspecting the wind turbine.
In another aspect of the present invention, a system is provided for inspecting a wind turbine. The system includes at least one remotely operated aerial platform (ROAP), at least one non-destructive evaluation (NDE) device attached to the remotely operated aerial platform, and at least one distance measuring system attached to the remotely operated aerial platform. The distance measuring system is used for determining the distance between the remotely operated aerial platform and at least a portion of the wind turbine. The remotely operated aerial platform is positioned so that the non-destructive evaluation device captures data used for inspecting the wind turbine.
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The drive train of the wind turbine includes a main rotor shaft 116 (also referred to as a “low speed shaft”) connected to hub 110 via main bearing 130 and (in some configurations), at an opposite end of shaft 116 to a gear box 118. Gearbox 118 drives a high-speed shaft of generator 120. In other configurations, main rotor shaft 116 is coupled directly to generator 120. The high-speed shaft (not identified in
The ROAP 310 can take the form of a helicopter or blimp, or any other device capable of flight or sufficient maneuverability. A helicopter may have one or more main rotors, and may also include one or more tail rotors as well. Main rotors are typically oriented in one or more substantially horizontal planes and the tail rotor is typically oriented in a substantially vertical plane. However, helicopters with one or more main rotors may or may not have a tail rotor, as the main rotors can be used to change the direction of flight and/or spatial orientation. Additionally, the ROAP can be equipped with a Global Positioning System (global as well as local GPS) and flight control system to control the ROAP manually or autonomously, and/or to program the ROAP to follow a predefined flight trajectory while performing inspection or repair tasks. The ROAP can transmit the inspection data to a ground station or remote operator wirelessly. The ROAP can carry other accessories like a light source to enhance image retrieval, a laser pointer to create a bright contrast spot on the blade surface so that the lens of the camera can focus with this spot as a reference.
The non-destructive evaluation (NDE) device 320 can comprise a visual camera, an infrared camera, an acoustic transmitter, an acoustic receiver, a radiation source, and a radiation detector, or any other suitable evaluation device as desired in the specific application. Additional NDE devices can also be of the ultrasonic, radiographic, thermographic, and electromagnetic types. A camera can be used to acquire images of possible defects or damage, such as cracks, delaminations, discolorations, oil spillages or hot-spots. Acoustic receivers can be used to detect undesirable noises or vibrations. Radiation devices can be used to detect other damage.
The distance measuring system or device 330 can comprise contact type collision detectors, electromagnetic transceivers, acoustic transceivers, laser transceivers, radar transceivers, visually based receivers, and RFID tag transceivers. RFID tags can be located at various positions on and within the wind turbine 100. These RFID tags can be used to help determine the specific location of the remotely operated aerial platform 310.
Coupled to the blimp 400 is at least one non-destructive evaluation (NDE) device 450 and one or more distance measuring devices 460, which may be part of a distance measuring system. As described in conjunction with the helicopter-type ROAP, the NDE device 450 can comprise a visual camera, an infrared camera, an acoustic transmitter, an acoustic receiver, a radiation source, a radiation detector, an ultrasonic device, a radiographic device, a thermographic device, and an electromagnetic device or any other suitable evaluation device as desired in the specific application. Additional NDE devices 451 may also be distributed at various locations on chamber 410 or on blimp 400. The distance measuring devices may include contact type collision detectors, electromagnetic transceivers, acoustic transceivers, laser transceivers, radar transceivers, visually based receivers, and RFID tag transceivers.
The ROAP 510 may also be used to inspect the interior of the wind turbine 100. For an internal inspection, the ROAP can either originate from a location 535 within the wind turbine, or the ROAP may start its flight outside the wind turbine and then enter through the door 505 or any number of vents (not shown) or access hatches (not shown) located in various locations in wind turbine 100.
In one example, the ROAP 510 starts its flight at location 535 within the tower 104. The ROAP can fly up the tower 104 and enter the nacelle. In the nacelle, the ROAP 510 can inspect any of a number of components, including but not limited to, the generator, the gearbox, bearings, and high or low speed shafts. The ROAP 510 could also enter the hub 110 either from within the nacelle 102 or from an external hatch (not shown) located on hub 110.
As one example, the multiple ROAP charging dock 700 could be housed within wind turbine 100 and used to charge multiple ROAPs 510. The multiple ROAPs could be pre-programmed to inspect specific locations or components within the wind turbine. For example, a first ROAP could be sent on a path that inspects the tower 104, a second ROAP could be sent on a path to inspect the interior of nacelle 102 or components housed therein, and a third ROAP could be programmed to fly outside the wind turbine and inspect the blades. The multiple ROAPs could also be controlled remotely by a human operator or by a programmable computer.
For remote wind turbines located off-shore or in hard to reach land based environments, the array of ROAPs combined with the multiple ROAP charging dock 700, or a single ROAP with a single ROAP charging dock 600 can greatly facilitate wind turbine inspections. It is difficult for stationary cameras to capture every possible region of interest, so the mobile ROAPs provide a greatly improved mobile vehicle for inspections. Offshore turbines can be inspected when desired and the ROAPs can be recharged during non-inspection time or staggered in use so that while a first group of ROAPs are being used, a second group of ROAPs are charging.
A mobile vehicle (e.g., a van or truck) can also use the multiple ROAP charging dock 700 to charge multiple ROAPs. While one or more ROAPs are out on inspection, other ROAPs can be charging. This will greatly reduce downtime during the inspection process. The ROAP can also be configured to utilize replaceable power sources, such as batteries or fuel cells, and solar panels (not shown) may be incorporated into the ROAP to extend flying time or to assist in recharging.
The ROAPs can also be equipped with wired or wireless transmission capability for receiving commands or programming, and for transmitting captured data. The ROAPs 510 can include USB connections or wireless links such as WIFI, Bluetooth® (a registered trademark of Bluetooth SIG), infrared devices or any other suitable wireless link. Complementary receivers and/or transmitters can be incorporated in the charging docks 600, 700 or in suitable electronics (e.g., computers, laptops, etc.) located within range of the ROAPs.
A repair apparatus 830 may also be attached to the ROAP 810. The repair apparatus 830 may comprise a main tube having a repair head 832. The repair head can include a stationary, rotating or telescoping member that uses an abrasive or grinding material. Abrasive material (e.g., sand, glass bead, baking soda blast media, aluminum oxide, walnut shells, etc.) can be used to knock off or dislodge debris or unwanted material or for preparing surfaces for subsequent repair layers. Grinding material (e.g., sanding disks/heads, cut off wheels, etc.) can also be used to remove unwanted material, as well as, for preparing surfaces for subsequent repair layers. The head 832 can also be used for the application of paint, adhesives and/or sealing material to the desired areas under repair. A motor or supply apparatus 834 can be used to power the head 832 or supply the head 832 with the desired material. In addition, both main tubes in the cleaning and repair apparatus may be comprised of telescoping members that can be used to extend or retract the nozzle 822 and head 832.
A global positioning receiver 840 can be attached to the ROAP 810, and the receiver 840 can be used to determine the relative location of the ROAP 810. The receiver 840 can also be used to navigate and/or maintain position of the ROAP 810 during flight. The global positioning receiver 840 may also be configured to transmit data back to a remote control unit, and this data can be used for navigation, positioning and inspection purposes.
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 have 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.
