Patent Application
20150027068
The subject matter disclosed herein relates generally to wind turbines, and more particularly to a tower base assembly for a wind turbine.
Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
As the sizes of wind turbines generally increase, the towers of the wind turbines may be modified to accommodate these increases. Such increases in tower size may require constructing the tower in segments and assembling the tower on-site. For example, an 80-meter tower may include three tower sections of varying diameter and thickness. Conventional base tower sections typically have a 4.3-meter maximum diameter and are about 10 to 20 meters long. The space envelope for transport by truck is about 4.3 meters (e.g. to comply with the maximum headroom of bridges), thus allowing a tubular section of approximately that diameter to fit within the space envelope. The space envelope for transport by rail is up to about 3.4 meters to about 4 meters on a side, thus allowing a tubular section of up to that approximate that diameter to fit within the space envelope. Present base sections, therefore, typically exceed the rail envelope and are shipped by truck. As such, the diameter of the base section has to be sized to fit within the space envelope and is transported in a horizontal position (i.e. the longitudinal length of the base section is parallel with the truck bed).
Further, down-tower electrical components, platforms, and other internal fixtures must be installed on-site to avoid disassembly during horizontal transportation of the tower base assembly, further increasing installation and maintenance costs. As such, conventional installation methods employ installing down-tower electrical components on a tower foundation and then using a large crane to lift and lower the base section around the down-tower electrical components.
Accordingly, an improved tower base assembly for a wind turbine would be desired. For example, a tower base assembly for a wind turbine that decreases transportation costs, while also decreasing installation and maintenance costs and time would be advantageous.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one aspect, a pre-assembled tower base assembly for a wind turbine configured for transportation to a wind turbine site is disclosed. The pre-assembled tower base assembly includes a tubular side wall defining an internal volume, a first flange portion at a first end of the tubular side wall; and a second flange portion at a second end of the tubular side wall opposite to the first end. The first flange portion is configured to couple to a tower foundation. The second flange portion is configured to couple to an adjacent tower section. The first and second flanges define a maximum longitudinal extension therebetween, the maximum longitudinal extension being a maximum height permitted for rail or truck transport. A down-tower electrical assembly is installed within the internal volume of the tubular side wall. Accordingly, the pre-assembled tower base assembly is delivered to a wind turbine site with the down-tower electrical assembly already installed and does not require large, costly cranes for installation.
In a further aspect, another embodiment of a pre-assembled tower base assembly for a wind turbine configured for transportation to a wind turbine site is disclosed. The pre-assembled tower base assembly includes a tubular side wall including a plurality of annular segments, at least one platform assembly, and a down-tower electrical assembly. Each annular segment is coupled to another annular segment at a seam, wherein the coupled annular segments define a maximum longitudinal extension, a maximum lateral extension, and an internal volume. The maximum longitudinal extension corresponds to a maximum height permitted for rail or truck transport. The at least one platform assembly is installed within the internal volume of the tubular side wall. Additionally, the down-tower electrical assembly is installed atop the platform assembly and within the internal volume.
In yet another aspect, a method for transporting a pre-assembled tower base assembly of a wind turbine to a wind turbine site is disclosed. The method includes a step of providing a tower base assembly defining a maximum longitudinal extension, a maximum lateral extension, and an internal volume. The maximum longitudinal extension corresponds to a maximum height permitted for rail or truck transport. The method further includes installing a down-tower electrical assembly within the internal volume of the tower base assembly. After installing the down-tower electrical assembly, the method also includes transporting the tower base assembly to a wind turbine site.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
Generally, the present disclosure is directed to a pre-assembled tower base assembly for a wind turbine, wherein the tower base assembly and an installed down-tower electrical assembly may be shipped together as one unit. For example, the tower base assembly may be shipped in a vertical or upright position with the down-tower electrical assembly pre-assembled within the tower base assembly before the tower base assembly arrives at a wind turbine site. More specifically, all necessary fixtures, appurtenances, and platforms may be included inside the tower base assembly to properly secure the down-tower electrical assembly during transportation. As such, the tower base assembly is delivered to a wind turbine site in a ready-to-use or operational configuration. Such a configuration reduces transportation costs and eliminates the need for large, costly cranes once the tower base assembly arrives on site.
Referring to the drawings,
As further shown in
In various embodiments, the tower base assembly 30 and the tower sections 14 may be formed from a suitable metal or metal alloy, such as carbon steel. Alternatively, however, the tower base assembly 30 and the tower sections 14 may be formed from any suitable materials, such as, for example, various suitable composite materials. Additionally, the tower base assembly 30 and the tower sections 14 generally have a cylindrical shape. However, it should be understood that the tower base assembly 30 and the tower sections 14 may have any other desired shape and that the outer shape of the tower base assembly 30 is adjusted to the cross-section of the tower 12. For example, the tower base assembly 30 may have a square or rectangular shape.
Referring now to
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In one embodiment, as illustrated in
Referring now to
In further embodiments, the first flange portion 24 may include first through-holes 50, 52 spaced generally circumferentially about the first flange 24. The first through-holes 50, 52 are grouped into outer through-holes 50 located within the outer portion 44 of the first flange portion 24 and inner through-holes 52 located within the inner portion 32 of the first flange portion 24. Second through-holes 54 are similarly formed within the second flange portion 26 and spaced generally circumferentially about the second flange portion 26.
Referring to
Referring back to
In other words, the tower base assembly 30 is about as wide as it is high. For example, in one embodiment, the width D1 of the tower base assembly 30 may be in the range of about 4000 millimeters (mm) to 5000 mm and the height H may be in the range of about 3500 mm to about 4500 resulting in an aspect ratio, i.e. height-to-diameter ratio, of about 0.8 to about 1.0. In one embodiment, the height H of the tower base assembly 30 is smaller than or equal to 4.3 meters (m) (i.e. corresponding to standard transportation limits), more specifically from about 3300 mm to 4300 mm, even more specifically, 3800 mm to 4300 mm. As such, the tower base assembly 30 may be transported in an upright or vertical configuration without restriction since it does not exceed the maximum headroom of bridges (i.e. the transportation height limit).
Though the height H is designed such that it may be transported in an upright position, the height H is also tall enough to house the down-tower electrical assembly 38 in an operational configuration. As used herein, the term “operational configuration” is defined generally as a ready-to-use configuration. Accordingly, once the pre-assembled tower base assembly 30 is delivered at the wind turbine site, the only remaining installation step is to secure the tower base assembly 30 to the foundation 15. Furthermore, the weight of the tower base assembly 30 is typically smaller than or equal to 20,000 kg, more specifically 10,000 kg, even more specifically, 5000 kg. Such a configuration eliminates the need for a large, costly crane to lift the tower base assembly 30 around the down-tower electrical assembly 38 when the pre-assembled tower base assembly 30 arrives on site. Accordingly, the tower base assembly 30 is relatively small and can be handled even by a single small mobile crane. Since the tower base assembly 30 can be handled by a single small crane, the costs are considerably reduced compared to conventional construction necessitating two larger cranes.
Referring still to
The down-tower electrical assembly 38 may include a variety of electrical components associated with wind turbine operation. For example, in one embodiment, the down-tower electrical assembly 38 may include any one of or combination of the following components: one or more electrical cabinets 39, electrical equipment, such as a transformer, a plurality of circuits, fixtures, appurtenances, or a control system. In a further embodiment, the electrical cabinets 39, for example, may be the distribution cabinets for auxiliaries of the entire wind turbine 10 and may provide access for operation and maintenance work. Additionally, the electrical assembly 38 may allow for full control and operation of the wind turbine 10, as well as a means for providing information on all operated and measured signals.
As mentioned, the electrical assembly 38 may be mounted on a platform assembly 37 as shown in
It should be understood that the platform assembly 37 may be designed with any suitable dimensions so as to fit within the tower base assembly 30. For example, as shown in
Referring now to
Additionally, any number of annular segments 40 may be utilized to achieve the desired longitudinal extension H. In one embodiment, as shown in
Still referring to
Referring now to
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The method 100 may further include the step 104 of installing a down-tower electrical assembly 38 within the internal volume 36 of the tower base assembly 30. In another embodiment, the step 104 of installing the down-tower electrical assembly 38 may further include securing one or more components associated with the down-tower electrical assembly 38 within the internal volume 36 of the tower base assembly 30. As mentioned, the one or more components associated with the down-tower electrical assembly 38 may include any one of or combination of the following components: one or more electrical cabinets 39 and/or electrical equipment, such as a transformer, a plurality of circuits, fixtures, appurtenances, platforms, or a control system. Additionally, the method 100 may further include the step 106 of, after installing the down-tower electrical assembly, transporting the tower base assembly 30 to a wind turbine site.
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 include 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.
