PEDERSEN GUNNAR K STORGAARD (DK)
US20040253109A1 | 2004-12-16 | |||
EP2650537A1 | 2013-10-16 | |||
EP3001029A1 | 2016-03-30 | |||
DE102012010019A1 | 2013-11-28 | |||
US20160362180A1 | 2016-12-15 |
CLAIMS 1. A method of handling a wind turbine component for assembly or maintenance, the method comprising: coupling one or more unmanned aerial vehicles (80, 82) to a hub (66) of a wind turbine (60); and controlling the one or more unmanned aerial vehicles (80, 82) to apply torque to the hub (66). 2. The method of claim 1 , wherein the one or more unmanned air vehicles (80, 82) are coupled to the hub (66) by a wind turbine blade (68a). 3. The method of claim 2, wherein the wind turbine blade (68a) is transported from a storage location to an assembly position proximal to the hub (66) in order for that blade (68a) to be attached to the hub (66). 4. The method of claims 2 or 3, including attaching the one or more unmanned air vehicles (80, 82) to the blade (86a) by attachment means. 5. The method of claim 4, wherein the attachment means comprises a tubular member (84) that is received over at least a portion of the blade (86a). 6. The method of any of claims 1 to 5, further including controlling the one or more unmanned aerial vehicles (80, 82) to decouple from the hub (66) and to recouple to the hub (66) in a second position thereon so as to apply a torque to the hub (66) at that second position. 7. The method of claim 6, wherein recoupling the one or more unmanned aerial vehicles (80, 82) includes transporting a wind turbine blade (86b) from a storage location to an assembly location proximal to the hub (66) so that it can be attached thereto. 8. The method of any of claims 1 to 7, including applying a further torque to the hub (66) using a drive mechanism (78) associated therewith. 9. The method of claim 8, wherein the drive mechanism (78) is a turning gear associated with a gearbox of the wind turbine (60). 10. A method of assembling a rotor (64) of a wind turbine (60), the rotor (64) including a hub (66) mounted to a nacelle, and a plurality of wind turbine blades (68), the method comprising: installing at least a first wind turbine blade (68a, 68b)) onto the hub (66), wherein the hub (66) includes a counterweight (92) that at least partially balances the mass of the one or more blades (68a, 68b); rotating the hub (66) about a longitudinal axis thereof so as to move the counterweight (92) into a predetermined angular position with respect to the nacelle; and removing the counterweight (92) from the hub (66) and installing a further wind turbine blade (68c) onto the hub (66). 1 1 . The method of claim 10, including installing the counterweight (92) on the hub (66), before installing the first wind turbine blade (68a) onto the hub (66). 12. The method of claim 1 1 , wherein the counterweight (92) is installed at a blade root socket defined by the hub (66). 13. The method of claims 1 1 or 12, including locking the hub (66) against rotation following installation of the counterweight (92). 14. The method of any of claims 10 to 13, further including locking the hub (66) against rotation once the hub (66) is in the predetermined angular position and before the counterweight (92) is removed from the hub (66). 15. The method of any of claims 10 to 14, including installing a further wind turbine blade (68b) onto the hub (66). 16. The method of claim 15, wherein the further wind turbine blade (68b) is installed onto the hub (66) before rotating the hub (66) about its longitudinal axis to locate the counterweight (92) in the predetermined angular position. 17. The method of any of claims 10 to 16, wherein the counterweight (92) and the wind turbine blades (68a, 68b) are spaced at substantially equal angular positions about the hub (66). 18. A method of assembling a rotor (64) of a wind turbine (60), the rotor including a hub (66) mounted to a nacelle, and three wind turbine blades (68a, 68b, 68c), said hub (66) having three evenly distributed blade root sockets, the method comprising: orienting the hub (66) with its blade root sockets in a 12 o'clock, 4 o'clock and 8 o'clock orientation, respectively; using at least one unmanned air vehicle (80, 82) coupled to a respective wind turbine blade (68a, 68b) to install wind turbine blades (68a, 68b) in the 4 o'clock and 8 o'clock oriented blade root sockets; applying torque to the hub (66) and thereby turning the 12 o'clock positioned blade root socket into a 3 o'clock or 9 o'clock orientation; and using at least one unmanned air vehicle (80, 82) coupled to a wind turbine blade (68c) to install the wind turbine blade (68c) in the 3 o'clock or 9 o'clock oriented blade root sockets. 19. The method according to claim 18, wherein the step of applying torque to the hub (66) is performed with the assistance of at least one unmanned aerial vehicle (80, 82) coupled to the hub (66). 20. The method according to claim 19, wherein said at least one unmanned aerial vehicle (80, 82) is coupled to the hub (66) by a wind turbine blade. 21 . The method according to any of claims 18 to 20, wherein the step of applying torque to the hub (66) is performed with the assistance of a counterweight (92) attached to the hub (66) and acting under the influence of gravity. |
WIND TURBINE COMPONENTS
FIELD OF THE INVENTION
This invention is directed to handling components of a wind turbine, during assembly or maintenance operations, for example.
BACKGROUND OF THE INVENTION
Wind turbines are large structures which comprise many heavy components such as generating equipment, tower segments, wind turbine blades and so on. As such, the assembly and maintenance of wind turbines presents a significant technical challenge due to the size and mass of the components involved.
A particular challenge is the task of assembling the wind turbine blades onto the hub. Typically this is achieved by installing the blades one-at-a-time onto a preinstalled hub that is mounted to a respective nacelle at the top of a wind turbine tower. A crane is used to support each blade and move it into position adjacent to the hub so it can be attached by specially trained assembly workers. Once the blade is attached to the hub, the hub must be rotated in order to move it into the correct position for a second blade to be attached.
Rotation of the hub is typically achieved using a turning gear. As is known, the turning gear commonly includes one or more electric motor(s) that cooperates with the main shaft of the wind turbine via the gear box in order to rotate the hub during installation and maintenance operations. One drawback with a hub turning system based on a turning gear is that it puts a very high load on the components of the gearbox. Each blade may weigh in excess of 15 tonnes, so in order to rotate the hub the turning gear must apply a high torque to the gearbox. In practice, the torque applied to the gearbox during an assembly procedure may be higher than typical torque levels experienced by the gearbox during operation. The gear box must therefore be designed to accommodate such torque levels, which increases the mass, size and cost of the gearbox.
It is against this background that the embodiments of the invention have been devised to provide an improved, more efficient, and cost effective approach for carrying out the installation of blades onto a hub during assembly and
maintenance operations.
STATEMENT OF INVENTION
In a first aspect of the invention, a method of handling a wind turbine component for assembly or maintenance comprises coupling one or more unmanned aerial vehicles to a hub of a wind turbine and controlling the one or more unmanned aerial vehicles to apply torque to the hub.
In some embodiments, the one or more unmanned air vehicles are coupled to the hub by a wind turbine blade.
The wind turbine blade may be transported from a storage location to an assembly position proximal to the hub in order for that blade to be attached to the hub. The method may further include attaching the one or more unmanned air vehicles to the blade by attachment means. The attachment means may comprise a tubular member that is received over at least a portion of the blade.
The method may further include controlling the one or more unmanned aerial vehicles to decouple from the hub and to recouple to the hub in a second position thereon so as to apply a torque to the hub at that second position. The recoupling the one or more unmanned aerial vehicles may includes transporting a wind turbine blade from a storage location to an assembly location proximal to the hub so that it can be attached thereto. In any of the embodiments above, the method may include applying a further torque to the hub using a drive mechanism associated therewith. The drive mechanism may be a turning gear associated with a gearbox of the wind turbine, for example. In a further aspect of the invention, there is provided a method of assembling a rotor of a wind turbine, the rotor including a hub mounted to a nacelle, and a plurality of wind turbine blades. The method comprises installing at least a first wind turbine blade onto the hub, wherein the hub includes a counterweight that at least partially balances the mass of the one or more blades, rotating the hub about a longitudinal axis thereof so as to move the counterweight into a predetermined angular position with respect to the nacelle and removing the counterweight from the hub and installing a further wind turbine blade onto the hub. In some embodiments, the further wind turbine blade is installed in the position from which the counterweight was removed from the hub.
The counterweight may be installed on the hub before installing the first wind turbine blade onto the hub.
The counterweight may be installed at a blade root socket defined by the hub.
The method may include locking the hub against rotation following installation of the counterweight. Additionally or alternatively, the method may include locking the hub against rotation once the hub is in the predetermined angular position and before the counterweight is removed from the hub. ln some embodiments, the method also includes installing a further wind turbine blade onto the hub. The further wind turbine blade may be installed onto the hub before rotating the hub about its longitudinal axis to locate the counterweight in the predetermined angular position.
In any of the embodiments described above, the counterweight and the wind turbine blades are spaced at substantially equal angular positions about the hub. In a further aspect of the invention, there is provided a method of assembling a rotor of a wind turbine, the rotor including a hub mounted to a nacelle, and three wind turbine blades, said hub having three evenly distributed blade root sockets. The method comprises: a first step of orienting the hub 66 with its blade root sockets in a 12 o'clock, 4 o'clock and 8 o'clock orientation, respectively, using at least one unmanned air vehicle coupled to a respective wind turbine blade to install wind turbine blades in the 4 o'clock and 8 o'clock oriented blade root sockets, applying torque to the hub 66 and thereby turning the 12 o'clock positioned blade root socket into a 3 o'clock or 9 o'clock orientation. using at least one unmanned air vehicle coupled to a wind turbine blade to install the wind turbine blade in the 3 o'clock or 9 o'clock oriented blade root sockets,
The step of applying torque to the hub may be performed with the assistance of at least one unmanned aerial vehicle coupled to the hub. For example, said at least one unmanned aerial vehicle may be coupled to the hub by a wind turbine blade.
In some embodiments, the step of applying torque to the hub may be performed with the assistance of a counter weight attached to the hub and acting under the influence of gravity.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described by way of example with reference to the accompanying drawings, in which:
Figure 1 is a schematic diagram of an exemplary unmanned air vehicle system for use in the embodiments of the invention;
Figure 2 is a schematic diagram of a ground station for use with the drone system of Figure 1 ; Figures 3 to 9 show a wind turbine at various stages of installation of the blades according to an embodiment of the invention;
Figure 10 illustrates an exemplary process for installing blades on a wind turbine;
Figures 1 1 to 15 show a wind turbine at various stages of installation of its blades according to a further embodiment of the invention; and
Figure 16 illustrates a further exemplary process for installing blades on a wind turbine. DETAILED DESCRIPTION OF EMBODIMENTS
Embodiments of the invention provide unmanned aircraft systems (UAS) and unmanned air vehicles (UAV), also referred to as drones, in order to provide an efficient approach to handle wind turbine components to aid wind turbine assembly and maintenance. For brevity, this discussion will refer to a 'drone' as any type of unmanned air vehicle, be it a relatively small-scale rotorcraft such as a multirotor, for example a tricopter, quadcopter, pentacopter, hexacopter, octocopter or a larger-scale unmanned helicopter.
In general the embodiments of the invention provide a novel approach for handling wind turbine blades, for example when installing blades on a wind turbine, in which drones are used to lift, orient and position the blades. In principle a single drone may be used for this purpose, which may be a single heavy-lift drone, such as a remote controlled helicopter, or even a drone such as a multirotor having a lower lift capacity, for smaller lighter blades. However, the concept extends to a plurality of drones, working together in cooperation to lift a heavy load to the required position and in the correct orientation. To put the invention into context, Figure 1 illustrates a system diagram of a typical drone architecture 20 which may be used in the implementation of the embodiments of the invention. In overview, the drone 20 includes: a control system 22, one or more propulsion units 24, a power system 26, a
communication system 27, a sensor suite 28, mission planning system 29 and a navigation system 30. The drone system 20 may be operated in conjunction with a ground-or base-station computer system 31 , hereinafter referred to as the 'ground-station', which will be described in more detail later with reference to Figure 2. The control system 22 is the main computing unit that controls the flight of the drone 20 by controlling the propulsion units 24 based on inputs from the sensor suite 28 and navigation system 30. The control system 22 may implement remote control flight based on received control inputs from a ground based controller, autonomous flight, based on its internal mission planning algorithms, or semi- autonomous flight, in which a blend of on-board mission planning and ground based direction are used. The main responsibility of the control system 22 is as a lower layer controller which is responsible for positional control of the drone (altitude and lateral position), attitude control (pitch, roll and yaw), and velocity control (horizontal and vertical speed) based on remote control actions or based on self-generated flight directions. The control system 22 comprises a suitable processing environment having a processor 32 and a memory 34 with associated on-board communications functionality, such as a data bus, so it is able to communicate with other on-board systems.
To directly control the flight profile the control system 22 communicates with the one or more propulsion units 24. Four propulsion units 24 are shown here, as would be consistent with the drone system 20 being a multirotor. However, more or fewer propulsion units are also appropriate. For example an autonomous helicopter may have a single propulsion unit. The propulsion units may be any suitable units for providing controllable flight for the drone, and may be electric motors driving suitable rotor blades, as are typical with multirotor of varying size and lift capacities. However, the propulsion units 24 may also be gas turbines or internal combustion engines, for example.
The on-board power system 26 is selected to be suitable for the propulsion units 24. For example, for electric motors the on-board power system 26 may be a battery pack, a fuel cell, or even an external power plug so as to receive electrical power from an external source. Conversely, the power system 26 could be an onboard fuel tank in the event that the propulsion units are gas-turbines or ICEs. The communication system 27 provides the means to send and receive data to and from systems that are external to the drone 20. For example, the drone 20 may send telemetry data to the base station 31 , and may send positional, attitude and velocity data to other drones operating in the area, either as part of a drone swarm or operated independently. The communication system 27 may also receive data from external systems, and in this context it may receive remote control commands from the base station if the drone 20 is operated in remote control flight mode. Alternatively it may upload mission data from the base station. The communication system 27 also permits incoming and outgoing communication with other drones so that flight paths and mission objectives can be coordinated with them to achieve a collective goal. The communication system may direct signals by any means known in the art including, but not limited to, cellular or other phone-based networks, over remote control radio frequency links, UHF or L-band frequency links, microwave frequency links, or other appropriate datalinks, networks, or communication paths. The sensor suite 28 is operably connected to the control system 22 and provides appropriate sensor data to assist with the operation of the drone. For example, the sensor suite may comprise proximity detectors, a global navigation satellite system/global positioning system (GNSS/GPS) unit for positioning control, optical still and video cameras for carrying out inspection and guidance tasks, inertial navigation systems to name a few examples. Typically such a sensor suite 28 would be adaptable to carry more or fewer sensors as required for a particular task. Note that in this context the GPS unit may receive signals directly from satellites in order to fix the position of the drone, although another option would be to implement a differential GPS system (known in the art) which receives signals from a ground-based differential GPS beacon in order to provide a higher positional accuracy compared to direct GPS. Note that a GPS unit 36 is shown here as integral with the navigation system 30.
Mission planning system 29 provides a link to the base station to store missions that have been generated thereon and to which the drone follows in use. The mission planning system 29 may include suitable memory storage and algorithms to store, provide and generate on the fly appropriate mission objectives, waypoints, operational envelopes and so on.
Navigation system 30 provides control inputs to the flight control system 22 regarding path following based on input from GPS data from the sensor suite 28.
In addition to the operational systems described above, the drone 20 also includes a cargo connection 38 to provide a releasable connection to a cargo so that the drone may be connected to and released from a cargo either by an operator or by an electronically controlled hook, for example. The sensor suite 28 may include a suitable load sensor to detect properties of the cargo such as its mass and load bias/centre of gravity.
Having described the functional components of the drone 20, discussion will now turn to the ground station 31 as shown in Figure 2. Ground station 31 provides a ground-based control hub 66 for the one or more drones 20 and is suitable equipped with a computing platform 40 having an appropriate processing module 42 and memory storage 44. The computing platform implements a suitable ground station software package 46 to provide appropriate ground station facilities for controlling and coordinating the one or more drones. For example, the software package may include telemetry feeds, status information updates, first person visual (FPV) feeds, mission planning interfaces and algorithms and so on. A user interface 48 is provided to enable to a user/operator to view data relating to the drone system and to input control and parameter data into the ground station. The user interface 48 may comprise of a display screen and audio output, and a user input means such as a keyboard, joystick, mouse, onscreen buttons or a combination of these. The ground station also has a communications system 50 in order to send data to and receive data from the one or more drones. It should be appreciated that the above description of a drone system 20 is intended as merely an example of the main components of an autonomous air vehicle and that other components may also be included in a typical system. In general, it should be noted that drones for use in the embodiments of the invention are known and are able to perform in remote control flight modes, semi- and fully-autonomous flights modes, and are able to carry out manoeuvres in a coordinated fashion in fixed positional relationship with other drones.
A suitable type of drone is the Griff series of drones from Griff Aviation.
The above discussion focuses on an example of a drone system which may be used to give the invention context. The discussion will now focus on particular functionality of the drone system. The present invention relates to the handing of wind turbine blades. The described embodiments particularly relate to installation of rotor blades on a wind turbine. It will be appreciated that the present invention may be applied to other situation such as maintenance or disassembly of wind turbines. By way of background, Figure 9 shows a typical wind turbine arrangement in in which the blades have been installed. The wind turbine 60 comprises a tower 62 and a rotor 64 arranged on the tower 62. The rotor 64 comprises a central hub 66 and a plurality of blades 68 mounted on the hub 66 and extending therefrom. In the described embodiments the wind turbine 60 comprises three rotor blades 68, evenly spaced around the hub 66, however it will be appreciated that the invention may also be applied to wind turbines have one, two, four or more blades having any arrangement as known in the art.
Referring now to Figure 3, each blade 68 comprises an airfoil portion 70 for generating lift for energy production and a root portion 72 for attachment to the hub 66. The root portion 72 may be secured in a socket 74 of the hub 66 using a plurality of fasteners (not shown), for example. Various means for securing the blade 68 to the hub 66 are well known in the art and so will not be discussed in detail here. For simplicity, the direction a blade 68 extends from the hub 66 will be referred to in terms of a time on a notional clock in which the rotor hub 66 is at the centre. For example, a blade in a '3 o'clock position' extends from the hub 66 in a horizontal direction on the right hand side thereof when looking at front of the wind turbine, as shown in Figure 3. A blade 68 in a '6 o'clock position' extends downwards from the hub 66 in a vertical direction, and so on.
In the described embodiments, the rotor 64 comprises a locking mechanism for locking the position of the hub 66 and any blades mounted therein such that no rotation of the hub 66 or blades can occur. Such locking mechanisms are also well known in the art and so will not be discussed in detail.
The hub 66 may be rotated using a turning gear 78, shown schematically in Figure 5. The turning gear 78 may comprise one or more motors 79 for providing sufficient torque to turn the hub 66 and any blades 68 attached thereto. The turning gear 78 further comprises an engagement means 81 for engaging and mechanically coupling with the hub 66 for rotation thereof. The exact
configuration of the motor 79 and engagement means 81 will be dependent on the size and configuration of the hub 66 to which it is attached and the torque requirements of the rotor 64. In Figure 5, the turning gear 78 is shown schematically as a separate component arranged to turn the hub 66. However, it would be appreciated that in practice the turning gear 78 would be housed within the wind turbine, for example within a nacelle thereof and may be a part of a main gearbox assembly, for example. During installation of the wind turbine 60 the tower 62 is constructed and the rotor hub 66 mounted thereon according to methods known in the art. Such methods may involve the use of cranes, for example. In accordance with an embodiment of the invention the blades 68 may be installed on the hub 66 in accordance with the method described below with reference to Figures 3 to 9 and shown schematically in Figure 10.
Prior to installation of the blades 68, the rotor hub 66 is locked into a first position using the locking mechanism such that no rotation of the hub 66 can occur. In the first position, a first socket 74 of the hub 66 is positioned such that a first blade 68a can be mounted to the hub 66 in a 3 o'clock position. The first blade 68a is then installed in a 3 o'clock position as shown in Figure 3. The first blade 68a may be installed using a crane. For example, the crane may hold the first blade 68a in a horizontal orientation using a harness and
manoeuvre the first blade 68a towards the hub 66 such that the root 74 of the blade 68a can be attached thereto. Figure 4 shows a further installation stage in which the harness or positioning equipment is removed and a plurality of drones 80, 82 is engaged with the first blade 68a via a sock 84. The illustrated embodiment shows a first drone 80 and a second drone 82 at spaced apart positions along the length of the first blade 68a. However, as described above, any number or configurations of drone may be used.
The sock 84 is a tubular member configured to surround a tip portion of the blade 68a, distal from the hub 66 such that the weight of the blade 68a can be supported by the drones 80, 82 attached to it. The drones 80, 82 may be attached to the sock 84 via any means known in the art, for example clips, clamps bolts, rivets or other fasteners. In the illustrated example, the drones 80, 82 are each attached to the sock 84 via a rope 86 that allows a range of motion of the drones 80, 82 relative to the sock 84 when mounted on the blade 68a.
In alternative embodiments, the first blade 68a may be installed on the hub 66 using drones. For example, drones may be attached to the blade 68a by a sock or other attachment means and lifted into position on the hub 66. The drones may then remain coupled to the blade after installation as shown in Figure 4.
Once the first blade 68a is installed and one or more drones 80, 82 are coupled to the blade 68a, via a sock 84 for example, the hub 66 is unlocked to allow rotation of the hub 66 and first blade 68a. Since the first blade 68a is in the 3 o'clock position, the hub 66 can rotate in a clock-wise direction, indicated by the arrow 88 in Figure 4, under the weight of the first blade 68a until the first blade 68a reaches about a 6 o'clock position. The drones 80, 82 support at least a portion of the weight of the first blade 68a via the sock 84 to control initial rotation of the hub 66, for example to prevent rapid acceleration of the blade 68a when the hub 66 is unlocked.
When the first blade 68a approaches a 6 o'clock position, a turning gear 78 is coupled with the hub 66 and continues to rotate the hub 66 and first blade 68a to a second position, as shown in Figure 5, for installation of a second blade. In the illustrated embodiment the second position of the hub 66 is reached when the first blade 68a is in about a 7 o'clock position.
Once the hub 66 is in the second position the hub 66 is locked and a second blade 68b is then installed at a 3 o'clock position as shown in Figure 6. The second blade 68b is installed in the same manner as described in relation to the first blade 68a above.
The hub 66 is then unlocked and the turning gear 78 then rotates the first and second blades 68a, 68b towards a third position in which a third blade is to be mounted. As the hub 66 is rotated to the third position, a variation in torque will be from the turning gear 78 due to the unbalanced distribution of weight of the first and second blades 68a, 68b around the hub 66.
More specifically, the centre of gravity 90 of the rotor 64 is offset from the hub 66 between the first and second blades 68a, 68b, as shown in Figure 6. When the centre of gravity 90 of the rotor 64 is positioned to the right of the hub 66, as it is immediately after installation of the second blade 68b in Figure 6, this exerts a clock-wise torque on the hub 66 and therefore facilitates clock-wise turning of the hub 66 by reducing the torque required by the turning gear 78. In other words, the force exerted on the hub 66 by the weight of the blades is acting in the direction of motion of the hub 66. As such, the torque required from the turning gear 78 will be relatively low until the first and second blades 68a, 68b reach a balanced position at about 8 o'clock and 4 o'clock respectively when the centre of gravity 90 of the rotor 64 will be directly below the hub 66.
After reaching the balanced position, further clockwise motion of the blades 68a, 68b moves the centre of gravity 90 of the blades to the left of the hub 66 as shown in Figure 7. This results in an anti-clockwise torque exerted on the hub 66 by the weight of the blades 68a, 68b. As such, the torque required from the turning gear 78 to further turn the blades 68a, 68b will increase as the blades move further clockwise. The maximum torque required to turn the rotor 64 occurs when the centre of gravity 90 of the rotor 64 is positioned at a left most point relative to the hub 66. This is when the first and second blades 68a, 68b are at 1 1 o'clock and 7 o'clock positions respectively and is also the required position of the first and second blades 68a, 68b for installation of the third blade i.e. the third position.
In order to reduce the load on the turning gear 78 a plurality of drones 80, 82 are coupled to the first blade 68a, as shown in Figure 7, in order to provide an additional lifting force to the first blade 68a to overcome at least some of the anticlockwise torque caused by the weight of the first and second blades 68a, 68b. ln embodiments, the drones 80, 82 are coupled to the first blade 68a when the rotor 64 reaches a position in which the torque experienced by the turning gear 78 exceeds a predetermined limit. In the illustrated example, the drones are coupled to the first blade 68a when the first blade 68a reaches a 9 o'clock position.
The drones are coupled to the first blade via a sock 84 mounted over a tip of the blade 68a in much the same way as described above. The sock 84 may also be attached to the hub via a cord or rope 85 to ensure that the sock 84 remains attached to the blade 68a as it is being lifted by the drones 80, 82.
The drones 80, 82 then exert a lifting force on the first blade 86a to facilitate turning of the rotor 64 to the third position for installation of a third blade.
Once the hub 66 is in the third position, the rotor 64 is locked and the third blade 86c is installed at a 3 o'clock position as shown in Figure 9.
The method described above is further illustrated in Figure 10. Figure 10 is a flow diagram showing various stages during the installation of blades according to an embodiment of the invention.
More broadly, the process comprises a first step 102 in which a first blade is installed at a 3 o'clock position. A second step 104 in which the first blade is turned such that the rotor is in a position for installation of a second blade. A second blade is then installed at a 3 o'clock positon in a third step 106.
The process further comprises a step 108 of turning the rotor, including the first and second installed blades, with a turning gear until a maximum torque range of the turning gear is reached. After the maximum range is reached, a further step includes attaching at least one drone, also known as a UAV, to the first blade. Subsequently, the first and second blades are turned using with the UAV to a position in which a third blade can be installed. A final step includes installing the third blade at a 3 o'clock position.
In an alternative embodiment the turning gear is dispensed with and the plurality of drones provides the force to turn the rotor between positions.
More specifically in Figure 5 when the first blade 68a approaches a 6 o'clock position, a plurality of drones 80, 82 (not shown) is coupled with the hub 66 and continues to rotate the hub 66 and first blade 68a to a second position, as shown in Figure 5, for installation of a second blade. In the illustrated embodiment the second position of the hub 66 is reached when the first blade 68a is in about a 7 o'clock position.
Once the hub 66 is in the second position the hub 66 is locked and a second blade 68b is then installed at a 3 o'clock position as shown in Figure 6. The second blade 68b is installed in the same manner as described in relation to the first blade 68a above.
The hub 66 is then unlocked and the plurality of drones 80, 82 (not shown) then rotates the first and second blades 68a, 68b though the positions shown in figures 7 and 8 towards a third position in which a third blade is to be mounted.
Once the hub 66 is in the third position, the rotor 64 is locked and the third blade 86c is installed at a 3 o'clock position as shown in Figure 9.
Figures 1 1 to 15 show a wind turbine at various stages of installation of rotor blades according to a further embodiment of the invention.
Prior to installation of the blades the rotor hub 66 is locked into a first position using the locking mechanism such that no rotation of the hub 66 can occur. In the embodiment of Figures 1 1 to 16, the first position of the hub 66 allows first and second blades to be installed at 4 o'clock and 8 o'clock positions
respectively.
Figure 1 1 shows a first stage of installation in which the hub 66 has been placed in the first position and locked using a locking mechanism as described above. A counterweight 92 is attached to the hub 66 at a 12 o'clock position. In the illustrated embodiment, the counterweight 92 is attached in a position
substantially corresponding to a desired position of a third blade. The
counterweight 92 may take any form and desirably has a mass greater than or equal to one of the blades. In embodiments, the counterweight 92 is configured such that it exerts a similar torque on the hub 66 as a blade. In preferred embodiments the counterweight 92 is configured to exert a greater torque on the hub 66 than one of the blades when installed. After the counterweight 92 is installed, first and second blades 68a, 68b are installed in the 4 o'clock and 8 o'clock positions respectively.
Figure 1 1 shows the first blade 68a being installed at a 4 o'clock position. The first blade 68a is installed by drones 80, 82. The drones 80, 82 are coupled to the blade by a sock 93 and harness. In alternative embodiments the drones 80, 82 may be coupled to the blade 68a by just a harness or other attachment means as known in the art. The drones 80, 82 are spaced apart from each other along the length of the blade 68a such that vertical movement of the drones 80, 82 relative to one another can control the angle of the blade 68a during installation. The blade 68a is lifted, oriented and positioned in the hub 66 by the drones 80, 82. The drones 80, 82 are then uncoupled from the blade 68a.
A second blade 68b is then installed in the hub 66 at an 8 o'clock position, as shown in Figure 12. The second blade 68b is installed by drones 80, 82 in the same manner as described in relation to the first blade 68a. In variations of the embodiment, the second blade 68b may be installed before the first blade 68a. Once the first and second blades 68a, 68b are installed the hub 66 is unlocked and rotated in a clockwise direction using a turning gear 78. The hub 66, first and second blades 68a, 68b are rotated to a second position that allows installation of a third blade. The second position corresponds to the first and second blades 68a, 68b being in a 7 o'clock and 1 1 o'clock position respectively.
The turning gear 78 could be dispensed with. In an embodiment the turning of the hub 66 is performed by a plurality of drones coupled to the hub 66, preferably the same drones that have been used during installation of the second blade 68b as they are already coupled to the hub 66.
The presence of the counterweight 92 moves the centre of gravity of the rotor 64 to a position closer to the hub 66 thereby reducing or eliminating the anti- clockwise torque exerted on the hub 66 by the first and second blades 68a, 68b.
In some embodiments, the counterweight 92 may be configured such that its centre of gravity of the rotor 64 is above and/or to the right of the hub 66 when the rotor is in the first position as shown in Figure 10. This results in the counterweight 92 exerting a clockwise torque on the rotor 64 when the lock is released to facilitate turning of the hub 66 by the turning gear 78.
When the rotor 64 is in the second position the counterweight 92 is removed. As shown in Figure 14, the counterweight 92 may be removed using drones 80, 82, but a crane may also be used to remove the counterweight. It should be noted at this point that a crane could also be used to install each of the blades, instead of drones. The drones 80, 82 may be configured to disengage the counterweight 92 from the hub 66 and move it to an alternative location away from the hub 66. Once the counterweight 92 is removed, the third blade is then installed in the 3 o'clock position as shown in Figure 15. The method described above is further illustrated in Figure 16. Figure 16 is a flow diagram showing various stages during the installation of blades according to an embodiment of the invention.
More broadly, the process comprises a first step 202 of locking the rotor. A counterweight is then installed at step 204. Further steps 206, 208 include installing a first blade at a 4 o'clock position and installing a second blade at an 8 o'clock position. The rotor is then unlocked at step 210 and subsequently, the first and second blades are turned around the hub with the counterweight balancing the weight of the blades about the hub, as shown in step 212.
A further step 214 includes removing the counterweight such that a third blade can be installed at a 3 o'clock position at step 216.
In variations of the embodiments above, cranes or other lifting equipment may be used in addition to or instead of drones to assist with the turning of the rotor during installation.
Next Patent: SMOKE VALIDATION PROCESS FOR WIND TURBINES