Patent Application
20250020105
The invention relates to a method and a tool for installation, maintenance and/or removal of blades to an offshore wind turbine.
For offshore wind turbines it is generally required to install their blades at the offshore site where the turbine will be operated, because the large size of the turbine and the blades makes it impractical to transport a turbine to the offshore site in a fully assembled state, e.g. from an onshore assembly site. A known blade offshore installation method is based on lifting the blades suspended in a rope into installation position with a crane. The installation position is generally a position where an end of the blade can engage, e.g. mate with, and be coupled with, the nacelle at the top of the tower of the turbine.
With the known method, blades for the wind turbines are lifted in an about horizontal position using a lifting yoke, also known as a spreader bar, suspended in a crane rope. It is understood that horizontal position is here meant to be a lying position and does not refer to exact alignment with a horizon. Similarly, vertical position is understood to be a standing position.
In the known method, the blades are lifted with the yoke and swung into the mating position using a high reaching crane. The procedure with the blade/yoke suspended in a rope is very weather sensitive and the weather conditions, in particular wind and/or waves, put restrictions to the operationability to the existing installation method. As the wind is increasing with height, the known method will become even more weather sensitive, in particular in view of the trend towards increasingly taller offshore wind turbines.
The number of vessels with the needed height capacity will thus become limited and especially in the future this will be critical in order to install all the planned offshore windfarms. When the wind turbines get higher and the blades get longer and heavier the vessel capacity will become critical.
Therefore, improvements are desired in the field of installation, maintenance and/or removal of blades to an offshore wind turbine.
An object of the present invention is to enable easier installation of a wind turbine blade to a nacelle of an offshore wind turbine, in particular for a relatively large wind turbine and/or in relatively poor weather conditions. An object is to at least partly alleviate one or more challenges of known installation methods, such as those identified in the background section above. An object is to at least provide an alternative blade installation method.
Thereto, an aspect of the invention provides a method for installing a wind turbine blade to a nacelle of an offshore wind turbine, comprising the steps of:
The blade may subsequently be coupled to the nacelle, in particular in a final stage of the installation method. The blade handling steps may be repeated to install multiple blades to the same nacelle, with the blade receiving cart moving back down along the boom after installation of each blade to receive a subsequent blade. Once blade installation work at the tower has been completed, the tower gripping device unit may be released, and the blade receiving cart and the boom may be returned, e.g. to initial positions, so that the vessel can depart from the tower, e.g. to a further tower for further blade installations.
In an advantageous embodiment, the boom of the blade installer unit is aligned with the wind turbine tower. Such alignment is preferably performed prior to bringing, in particular upending, the boom towards the tower. Also, such alignment is preferably performed prior to extending the boom. To that end, the blade installer unit and/or the boom of the blade installer unit can be mounted movable with respect to the deck of the vessel. For example, the blade installer unit can be mounted on an XY-skid allowing for longitudinal movement and transverse movement over the deck with respect to the deck. Alternatively, the blade installer unit can be mounted on a Y-skid allowing transverse movement over the deck with respect to the deck. Alternatively and/or additionally, such a skid may also allow for angular movement with respect to the deck. By providing movement with respect to the deck on the deck of the vessel or barge, the position of the boom can be better aligned with the position of the tower, in particular without requiring highly precise positioning of the vessel or barge itself. In a further embodiment, the boom of the blade installer unit and/or the blade installer unit may be provided on a cantilever, which cantilever is movable with respect to the deck of the vessel, for example by the described XY-skid, and can, in extended position, reach beyond the deck. Alternatively or additionally, a skid may be provided between the boom and the cantilever. Apart from the aligning, the skid and/or the cantilever may be used bring the boom towards the tower, e.g. after some or all of the aligning.
The blade can be brought into a blade receiver of the blade receiving cart for example by a small crane, which may be a relatively simple and light crane, that can be mounted on the vessel or barge. The crane may be mounted on the deck, or onto or around legs of e.g. a jack-up vessel. It shall be appreciated that alternatively or additionally one or more other types of manipulators than a crane could be used.
In an embodiment, the method comprises extending the boom of the blade installer unit by moving an extendable boom portion outward with respect to a base boom portion of the boom, preferably prior to the actuating of the tower gripping device unit. It shall be appreciated that such a boom extension raises the level of the upper end of the boom with respect to the lower end of the boom, which lower end may be at a level of a deck of the vessel. Thus, when the blade receiving cart is moved towards, e.g. to, the upper end of the boom, the blade receiving cart may then be moved towards, e.g. to, the upper end of the extendable boom portion.
The boom of the blade installer unit may thus be an extendable boom, and is preferably a truss like boom. On the boom, and on the base boom portion and the extendable boom portion, rails can be provided on which the cart can be transported. Alternatively, the cart could move over chords of the boom portion in an alternative manner, e.g. with rollers or hooks.
The method may further comprise adjusting the boom angle, in particular when the boom is in extended position, i.e. when the extendable boom portion has been moved outward with respect to the base boom portion. The angle of the boom can for example be adjusted by moving the boom over the optional XY-skid or Y-skid or angular skid or by adjusting the position of the optional cantilever and/or by adjusting the position of the tower gripping device unit and/or by extending or retracting the optional extendable boom portion. For example, the boom angle may then be set more vertical to reduce the horizontal loads on the wind turbine tower. A more vertical boom angle may also be beneficial for allowing a more vertical blade position. Alternatively and/or additionally, by adjusting the angle of the boom, the blade may be brought more in position to mate with the nacelle.
By rotating the blade receiver with respect to the cart, more precisely with respect to a part, e.g. base, of the cart which is engaged with the boom, with the blade from a horizontal position to a vertical position, the blade can be brought in a position that can be aligned with the nacelle receiving opening, in particular at a downward facing side of the nacelle, in which the blade is to be received. The cart, in particular the blade receiver, can be further adjustable in horizontal and/or vertical and/or angular direction to more precisely align with the nacelle's receiving interface, such as a blade receiving opening. Such an alignment structure may be helpful for aligning the blade with the nacelle receiving opening to optimally mate the blade with the nacelle.
Then, the blade can be moved upwardly to be received in the nacelle's blade receiving opening and to be coupled with the nacelle. For example, the cart may be provided with a transport mechanism to bring the blade further upwards until it engages with the nacelle. The cart may be provided with blade receiving elements, in particular flexible blade receiving elements providing a soft but firm grip, holding the blade in all positions.
In an embodiment, the optional base boom portion of the boom can be provided with a tower strut that is extendable from the base boom portion and supports on the tower. Alternatively and/or additionally, the tower gripping device unit, e.g. at the upper end of the boom, can be connected to the tower, and can, upon extending of the extendable boom portion outward with respect to the base boom portion, move upwardly along the tower. The tower gripping device unit may be foldable connected to e.g. the upper end of the boom, such that during extending of the boom, the tower gripping device unit is folded inwardly towards the boom. When the boom is in extended position, the tower gripping device unit may be folded out to engage with the wind turbine tower. It shall be appreciated that in the present context, folding and foldability may involve one or more of various possible movements, including upward and rotation and e.g. translational extension, with respect to the boom. Alternatively, the tower gripping device could be substantially fixed with respect to the boom, i.e. not being adjustable, possibly apart from the gripping of the tower itself. The tower gripping device unit may have various embodiments allowing to make contact with the wind turbine tower to provide for sufficient support for the boom to lean onto the tower.
The vessel or barge can be any type of vessel used in offshore installation, such as a vessel using dynamic positioning, or a jack-up vessel, or a self-propelled or towed barge, etc.
The blade installer unit may be a telescopic structure fixed to a vessel or barge and extendable towards the top of the wind turbine tower.
The blade installer unit may comprise a telescopic boom, a blade receiving cart or trolley and a tower guide or tower gripping device unit.
The upper end of the boom may during use be connected to the top of the tower, and/or to another part of the tower, and move synchronised with the tower, at least with a part of the tower to which the upper end of the boom is connected. This means that the relative motion between the blade mating face, i.e. a face of the blade configured to mate with the nacelle, and the hub interface, i.e. an interface of the nacelle or hub configured to mate with the blade mating face, becomes very much less. The boom can also be denoted as chute.
The blade installer unit may thus be a tool that can install the blades from a reasonable sized vessel without needing a large crane, and by using the crane or other manipulator that may be available on the vessel.
The blade is preferably upended to almost vertical before mating with the nacelle of the wind turbine, resulting in a lower gripping height of the blade and thus reducing the motions imposed by wind and wave actions.
The blade can be fed into the cart, also denoted as chute trolley, at lowest possible level and raised by the guided chute trolley (cart) upwardly along the boom of the blade installer unit. Alternatively, the blade can be fed to the cart, in particular to the blade receiver of the cart, when the cart is already in a more upward position along the boom. On the vessel, the blades are preferably stored and seafastened in a storage position, From the storage position of the blades on the vessel, the blades can then be brought to the feeding position, i.e. a position in which the blade is received on the cart, by the crane or other manipulator by bringing the blade from the storage or seafastened position into the blade receiver of the cart. During this feeding, the blade may be fully guided by a yoke suspended in a crane structure, or in another type of manipulator.
The blade installer unit can thus be flexible in positioning and can be placed aft/forward or port/starboard on the vessel or barge. The size of the unit may enable the unit to be retrofit to existing vessels and the unit can also be used as a cost effective solution for blade and other maintenance service.
In the following, the invention will be explained further by means of a description of non-limiting examples shown in the figures, along with descriptions of examples of possible variations. The figures are schematic and merely show examples.
Although the invention has been explained further herein using examples and figures, these do not limit the scope of the invention as defined by the claims. Many variations, combinations and extensions are possible, as will be appreciated by the skilled person having the benefit of the present disclosure. All such variants are included within the scope of the invention as defined by the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2029292 | Sep 2021 | NL | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/NL2022/050539 | 9/26/2022 | WO |
