WO2021136569A1

WO2021136569A1 - Method for assembling a wind turbine blade

Info

Publication number: WO2021136569A1
Application number: PCT/DK2020/050398
Authority: WO
Inventors: Payam JAVADIAN
Original assignee: Vestas Wind Systems A/S
Priority date: 2019-12-30
Filing date: 2020-12-21
Publication date: 2021-07-08

Abstract

A method of assembling a split wind turbine blade (26) by connecting a tip section (26a) to a root section (26b) to form the wind turbine blade (26) is disclosed. The method includes supporting the root section (26a) on a root bed (62), the root section (26a) having a root section interface (44); supporting the tip section (26b) on a tip bed (68), the tip section (26b) having a tip section interface (46) spaced apart from and facing the root section interface (44), and the tip bed (68) having an adjustable first tip support (70) with a first height and an adjustable second tip support (72) with a second height; providing a rail (96) extending in a longitudinal direction of the blade (26) between the tip section interface (46) and the root section interface (44); providing a trolley (102) associated with said rail (96); coupling said tip section (26b) to said trolley (102) and moving the tip section (26b) towards the root section (26a) by moving the trolley (102) along said rail (96) until the tip section interface (46) is a predetermined distance (D) from the root section interface (44); adjusting at least one of the first and second heights of the first and second tip supports (70, 72), respectively, to align the tip section interface (46) with the root section interface (44); and connecting the tip section (26b) to the root section (26a) to form a connection joint (28). A trolley (102) and rail (96) system may be provided to pull the tip section (26b) toward the root section (26a).

Description

METHOD FOR ASSEMBLING A WIND TURBINE BLADE

Technical Field

The invention relates generally to wind turbines, and more particularly to systems and methods for assembling wind turbine blades, and especially split wind turbine blades.

Background

Wind turbines are used to produce electrical energy using a renewable resource and without combusting a fossil fuel. Generally, a wind turbine converts kinetic energy from the wind into electrical power. A horizontal-axis wind turbine includes a tower and an energy generating unit positioned atop of the tower. The energy generating unit typically includes a nacelle to house mechanical and electrical components, such as a generator, and a rotor operatively coupled to the components in the nacelle through a main shaft extending from the nacelle. The rotor, in turn, includes a central hub and a plurality of blades extending radially therefrom and configured to interact with the wind to cause rotation of the rotor. The rotor is supported on the main shaft, which is either directly or indirectly operatively coupled with the generator which is housed inside the nacelle. Consequently, as wind forces the blades to rotate, electrical energy is produced by the generator.

Wind turbines are typically assembled on the site where the wind turbine will operate. To that end, the various components of the wind turbine are transported to the site and are assembled. As wind turbines have grown in size to extract more energy from the wind, the components have also grown in size. For example, wind turbine blades have increased in length (extending between 50 to 80 meters in length) and will likely continue to get longer in the future. The increased length of the wind turbine blades has introduced a number of interesting design considerations for wind turbine designers and manufacturers. For example, production facilities, including the physical space as well as the equipment for manufacturing the blades (e.g., moulds, cranes and other handling equipment) must accommodate the increased size of the blades. Additionally, the logistics and transportation of such large blades becomes increasingly difficult as the length of the blades continues to increase. In the end, the production, handling and transportation of large-scale wind turbine blades is associated with significant challenges and high costs that may present a practical limit as to the length of wind turbine blades which may be manufactured.

One approach for addressing these issues is to provide a wind turbine blade having two or more sections which are subsequently coupled together to form the complete wind turbine blade at the work site. These multi-section blades are sometimes referred to as split blades or sectional wind turbine blades. Assembling the sections of a split blade presents its own challenges as the sections of the wind turbine blade must be accurately aligned as they are being joined to one another. Sometimes a crane is used to maneuver a split blade section adjacent to another split blade section so the two sections may be joined. Using a crane, however, may not provide sufficient accuracy in aligning the two sections to be joined. In addition, the terrain at the work site may not permit the use of a crane to assist with joining two split blade sections.

Wind turbine manufactures need a system and method to accurately move and align the blade sections during the joining process.

Summary

To these and other ends, a method of assembling a split wind turbine blade is provided. More particularly, a method for connecting a tip section to a root section to form a wind turbine blade includes supporting the root section on a root bed, the root section having a root section interface; supporting the tip section on a tip bed, the tip section having a tip section interface spaced apart from and facing the root section interface, and the tip bed having an adjustable first tip support with a first height and an adjustable second tip support with a second height; moving the tip section towards the root section until the tip section interface is a predetermined distance from the root section interface; adjusting at least one of the first and second heights of the first and second tip supports, respectively, to align the tip section interface with the root section interface; and once aligned, connecting the tip section to the root section to form a connection joint.

In one embodiment, adjusting the first height and/or the second height of the first and second tip supports, respectively, includes causing the tip section interface to be generally parallel to the root section interface. By way of example and without limitation, adjusting at least one of the first and second heights of the first and second tip supports, respectively, may include adjusting both the first and second heights; adjusting at least one of the first and second heights of the first and second tip supports, respectively, may include raising or lowering the tip section as a whole; adjusting at least one of the first and second heights of the first and second tip supports, respectively, may include rotating the tip section about an axis perpendicular to a longitudinal axis of the tip section; and adjusting at least one of the first and second heights of the first and second tip supports, respectively, may include rotating the tip section about a longitudinal axis of the tip section.

In one embodiment, the first tip support and the second tip support may be independently adjustable. For example, the first tip support may have two independently vertically adjustable tip supports and the second tip support may have two independently vertically adjustable tip supports. The independent adjustability of the first and second tip supports provides multiple of degrees of freedom of the movement of the tip section.

In an exemplary embodiment, moving the tip section towards the root section may include coupling the tip section to a trolley and moving the trolley along a rail to move the tip section towards the root section. By way of example, a winch may be used to move the trolley along the rail and pull the tip section towards the root section. Alternatively, the trolley may include a motor such that the trolley is self-powered to move along the rail. In one embodiment, a stop block may be positioned on the rail to stop the movement of the trolley along the rail such that the tip section interface is at the predetermined distance from the root section interface. In one embodiment, the predetermined distance may be zero and moving the tip section towards the root section includes moving the tip section until the tip section interface abuts the root section interface.

In one embodiment, the tip section interface and the root section interface may each include a plurality of threaded openings, and wherein connecting the tip section to the root section may include inserting a first end of a threaded rod into the threaded openings of the root section and inserting a second end of the threaded rod into corresponding threaded openings of the tip section. The method may further include securing a fairing to the connection joint to provide a smooth transition between the root section and the tip section.

Brief Description of the Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.

Fig. 1 is a perspective view of a wind turbine having a tower and an energy generating unit;

Fig. 2 is a perspective view of a two-section wind turbine blade joined at a connection joint;

Fig. 3 is a partial perspective view of the root section and the tip section separated at the connection joint;

Fig. 4 is an elevational view of a split blade rail assembly system according to an embodiment of the invention; and

Fig. 5 is an elevational view of the split bade rail assembly system of Fig. 4 with the tip section moved closer towards the root section.

Detailed Description of the Invention

With reference to Fig. 1 , a wind turbine 10 includes a modular tower 12 and an energy generating unit 14 disposed at the apex of the tower 12. As is conventional, the modular tower 12 may be coupled to a foundation 16 at a lower end thereof. The foundation 16 may be a relatively large mass, e.g., concrete, steel, etc., embedded in the ground and through which forces on the wind turbine 10 may be ultimately transferred. Although not shown, in an alternative embodiment, the foundation 16 may include an offshore platform or the like used in offshore wind turbine applications. The energy generating unit 14 includes the part of the wind turbine which transforms the energy of the wind into electrical energy. In this regard, the energy generating unit 14 typically includes a housing or nacelle 20, a rotor 22 having a central hub 24 and one or more blades 26 (e.g., three blades) mounted to the central hub 24 and extending radially therefrom, and a generator (not shown) for converting mechanical energy into electrical energy. In one embodiment, the energy generating unit 14 may further include a drive train (not shown), including a gear arrangement, interconnecting the rotor 22 and the generator. The generator and a substantial portion of the drive train may be positioned inside of the nacelle 20 of the wind turbine 10. In addition to the generator, the nacelle 20 typically houses miscellaneous components required for converting wind energy into electrical energy and various components needed to operate, control, and optimize the performance of the wind turbine 10. The wind turbine blades 26 are configured to interact with a free stream air flow to produce lift that causes the rotor 22 to spin or rotate generally within a plane defined by the wind turbine blades 26. Thus, the energy generating unit 14 is able to generate power from the airflow that passes through the swept area of the rotor 22. The tower 12 supports the load presented by the energy generating unit 14 and operates to elevate the energy generating unit 14, and especially the rotor 22, to a height above ground level or sea level at which faster moving air currents of lower turbulence are typically found.

The wind turbine blades 26 depicted in Fig. 1 are split blades or sectional wind turbine blades with at least two separable sections, a root section 26a and a tip section 26b. While Fig. 1 illustrates the wind turbine blade with two sections 26a, 26b, a split blade or sectional wind turbine blade may include additional sections to accommodate longer wind turbine blades 26.

Fig. 2 illustrates the split blade 26 of Fig. 1 with the root section 26a and the tip section 26b joined at connection joint 28. In an exemplary embodiment, the connection joint 28 may be located at approximately the mid-span of the split blade 26; however, other positions for a connection joint along the span of the split blade 26 are also possible. The blade 26 extends in a longitudinal - so-called spanwise - direction from a root end 30 to a tip end 36. The root section 26a includes a root end 30, a leading edge 32a, and a trailing edge 34a. Similarly, and using similar reference numbers, the tip section 26b includes a tip end 36, a leading edge 32b, and a trailing edge 34b. The connection joint 28 is covered by a fairing 38 that has a profile like that of the split blade so that there is a smooth transition between the root section 26a and the tip section 26b.

Fig. 3 illustrates the root section 26a separated from the tip section 26b at the connection joint 28. The root section 26b includes a root section interface 44 which is opposite to the root end 30. Similarly, the tip section 26b includes a tip section interface 46 which is opposite the tip end 36. One or more coupling devices may be used to connect the root section 26a to the tip section 26b. For example, a first coupling device may be associated with the tip section interface 46 and a second complimentary coupling device may be associated with the root section interface 44. The first coupling device may cooperate with the second coupling device to connect the tip section 26b to the root section 26a. One type of coupling device is the Nabrajoint developed by Nabrawind Technologies of Navarra, Spain. Fig. 3 illustrates a schematic version of a Nabrajoint coupling device, although not all structural components of the Nabrajoint are illustrated. To that end, the root section interface 44 and the tip section interface 46 have threaded openings 48 to receive threaded rods 50, with each thread rod having first and second threaded ends. The threaded ends of the rods 50 threadingly engage the threaded openings 48 and along with additional structural components (not shown) secure the root section 26a to the tip section 26b such that the root section interface 44 is spaced apart from the tip section interface 46 at a predetermined distance to accommodate the connecting hardware. When the root section 26a is fully secured to the tip section 26b, the fairing 38 may be placed over and secured to the connection joint 28 to provide a smooth transition between the root section 26a and the tip section 26b. While Fig. 3 illustrates one exemplary coupling device and methodology for joining the root section 26a to the tip section 26b, other coupling devices and methodologies may be used. These remain within the scope of the present disclosure.

To thread the threaded rods 50 into the threaded openings 48 in the tip section interface 46, the threaded openings 48 in the tip section interface 46 should be precisely aligned with the opposing threaded openings 48 in the root section interface 44. If the opposing threaded openings 48 are not aligned, it may be difficult if not impossible to turn the threaded rods 50 into the threaded openings 48 in the tip section interface 46. As illustrated and described, the threaded rods 50 are first threaded into the threaded openings 48 in the root section interface 44. It will be appreciated, however, that the threaded rods 50 may be threaded first into the threaded openings 50 in the tip section interface 46 first and then threaded into the threaded openings 48 in the root section interface 44.

Fig. 4 illustrates a blade assembly apparatus 60 in accordance with an embodiment of the invention. As will be explained, the blade assembly apparatus 60 helps to align the opposing threaded openings 48 in the root section interface 44 and the tip section interface 46. The blade assembly apparatus 60 includes a fixed root bed 62 with first and second root supports 64, 66 and a fixed tip bed 68 with first and second tip supports 70, 72. A support platform 74 extends between the first and second tip supports 70, 72 to further support the tip section 26b. The blade assembly apparatus 60 further includes a trolley system 76 positioned between the fixed root bed 62 and the fixed tip bed 68.

At the work site, a crane 80 lifts the root section 26a from a transport vehicle, such as a truck or train (not shown), and then places the root section 26a onto the fixed root bed 62. The root end 30 of the root section 26a is coupled to a root end coupler 82 such that the leading edge 32a is facing downwards. The root end couple 82 also prevents the root section 26a from moving longitudinally relative to the fixed root bed 62. The other end of the root section 26a rests in a root section saddle 84 that has a profile similar to the leading edge 32a. With the root section 26a secured to the fixed root bed 62, the threaded rods 50 may be threaded into the threaded openings 48 in the root section interface 44.

Similarly, the crane 80 lifts the tip section 26b from the transport device and places it onto the fixed tip bed 68 with the leading edge 32b facing downwards. The first and second tip supports 70, 72 each include a tip section saddle 86, 88 with a profile similar to the leading edge 32b to help support the tip section 26b. The support platform 74 may also support the leading edge 32b. The tip section 26b is not affixed to the first and second tip saddles 86, 88 so that the tip section 26b may move longitudinally relative to the fixed tip bed 68. In that regard, the tip section 26b slides along the support platform 74 and the first and second tip saddles 86, 88. To facilitate the tip section 26 sliding along the support platform 74 and the first and second tip saddles 86, 88, the support platform 74 and the first and second tip saddles 86, 88 may include low-friction surfaces, such as coatings, pads, or rollers, for example. In alternative embodiments, the root section 26a and the tip section 26b may be connected together while held in a horizontal orientation, i.e. with the leading and trailing edges 32a 32b of the blade defining a generally horizontal plane. This is sometimes described as a recumbent orientation of a blade. Accordingly, the root end saddle 84 and the tip end saddle 86, 88 may be configured to have the shape of a respective windward or leeward surface of the blade.

The trolley system 76 includes a rail 96 extending between the tip section interface 46 and the root section interface 44. Preferably, the rail 96 extends between the tip section interface 46 and the root section interface 44 at a height below said blade tip section 26b and said root section 26a. Preferably, said rail 96 extends between first and second rail supports 98, 100. As shown in Fig. 4 the rail 96 forms a bridge extending from beneath the root section interface 44 to beneath the tip section interface 46. In embodiments, a first end of the rail 96 may be positioned under a portion of the root section 26a while a second end of the rail 96 may be positioned under a tip section 26b. The first end of the rail 96 may in particular be underneath the root end 26a near said root section interface 44. The first end of the rail 96 may in particular be near said root section interface 44 on a side thereof, seen in a longitudinal direction of the blade 26, towards its root 30. The second end of the rail 96 may in particular be underneath the tip end 26b near said root section interface 46. The second end of the rail 96 may in particular be near said tip section interface 46 on a side thereof, seen in a longitudinal direction of the blade 26, towards its tip 36. The rail 96 may be arranged in fixed relation to the tip bed 68. The trolley system 76 also includes a movable trolley 102. The trolley 102 is movable in relation to the rail 96. The trolley 102 is also movable in relation to the tip bed 68. The trolley 102 has a set of wheels 104 which may be coupled to orcouplable to the rail 96. An adjustable stop block 106 is coupled to the rail 96. The trolley system 76 further includes a winch 108 and a cable 110 extending therefrom to the trolley 102. The trolley 102 may be coupled to an end of the tip section 26b with a strap 112 or other suitable device so the trolley 102 may pull the tip section 26b relative to the fixed tip bed 68. As the winch 108 pulls the trolley 102 along the rail 96 toward the tip section 26b (to the left in Fig. 4), the wheels 104 will contact the stop block 106 to prevent the trolley 102 from moving any further towards the tip section 26b. While rail 96 is illustrated as extending between the first and second rail supports 98, 100, it will be appreciated that the rail 96 could extend between second root support 66 and first tip support 70 and first and second rail supports 98, 100 could be eliminated. In this arrangement, the winch 108 would have to be relocated. While trolley system 76 includes the winch 108 coupled to first rail support 98, it will be appreciated that the trolley system 76 may eliminate the winch 108 and cable 110 and instead the trolley 102 itself may include a motor (e.g., electric or internal combustion) that is configured to move the trolley 102 along the rail 96. Other means for moving the trolley 102 along the rail 96 may also be possible.

After the tip section 26b is placed in the fixed tip bed 68, the crane 80 may be disconnected from the tip section 26b and the strap 112 is attached to the tip section 26b. The stop block 106 is positioned at a predetermined location so that when the tip section 26b is moved toward the root section 26b and the wheels 104 contact the stop block 106, the tip section interface 46 will be at a desired fixed distance D (Fig. 5) from the root section interface 44.,

As discussed above, the opposing threaded openings 48 need to be aligned so that the threaded rods 50 may be readily inserted into the threaded openings 48. To assist with aligning the opposing threaded openings 48, the first and second tip supports 70, 72 may be individually, vertically adjustable, as illustrated by arrows A and B (Fig. 5). To that end, each of the first and second tip supports 70, 72 may include lifting devices (not shown), such as screw jacks, hydraulic jacks, or electric jacks suitable to increase the overall length of each of the first and second tip supports 70, 72. By increasing the length of the first and second tip supports 70, 72 equally, the overall height of the tip section 26b may be raised or lowered to a desired height. The plane in which the tip section interface 46 lies is preferably generally parallel to the plane in which the root section interface 44 lies to insure the opposing threaded openings 48 are aligned. T o that end, the height of the first tip support 70 and the height of the second tip support 72 may be individually raised and lowered which will cause the tip section 26b to rotate about an axis perpendicular to the longitudinal axis of the wind turbine blade 26 (e.g., an axis coming out of the page from the perspective shown in Fig. 5). A controller (not shown) may be connected to the first and second tip supports 70, 72 with the controller being configured to change the height of each of the first and second tip supports 70, 72 as needed to align tip section interface 46 to the root section interface 44.

In one embodiment, the first tip support 70 may have two independently, vertically adjustable members and the second tip support 72 may also have two independently, vertically adjustable members. By separately controlling each of these four adjustable members, the tip section 26b may be raised or lower, rotated about the axis perpendicular to the longitudinal axis, and rotated about an axis parallel to the longitudinal axis so that the opposing threaded openings 48 may be aligned.

To join the tip section 26b to the root section 26a, the threaded rods 50 are first threaded into the threaded openings 48 in the root section interface 44. More specifically, one end of each threaded rods 50 is threaded into the threaded openings 48 further than required. In this manner, the tip section interface 46 can be moved to the desired distance D from the root section interface 44. With the tip section interface 46 at the desired distance D, the one end of the threaded rods 50 can be rotated outwardly from the threaded openings 48 in the root section interface 44 so that the other end of the thread rods 50 may be threaded into the threaded openings 48 in the tip section interface 46. In the end, both ends of the threaded rods 50 are substantially equally threaded into the threaded openings 48 in both the root section interface 44 and the tip section interface 46. As the tip section 26b is moved towards the root section 26a, the first and second tip supports 70, 72 may be raised or lowered as needed to align the tip section interface 46 to the root section interface 44. The first and second tip supports 70, 72 may be continually adjusted as the trolley 102 pulls the tip section 26b and the wheels 104 approach the stop block 106. Additional adjustments may be made as the threaded rods 50 approach the threaded openings 48 in the tip section interface 46. After the tip section 26b is mechanically joined to the root section 26a, the fairing 38 may be placed over the gap between the tip section 26b and the root section 26a to provide a smooth outer surface to the wind turbine blade 10.

It will be appreciated that different connection methods may be used which differ from the connection method described above. For example, in one embodiment, the tip section interface 46 may directly abut the root section interface 44. In that arrangement, the stop block 106 would be moved so that the wheels 104 of the trolley 102 could move unrestricted along the rail 96. Thus, aspects of the invention are not limited to a particular type of connection at the connection joint.

While the invention has been illustrated by a description of various embodiments, and while these embodiments have been described in considerable detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. For example, while the tip section 26b was described and illustrated as being raised/lowered/rotated relative to the fixed root section 26a to align the opposing interfaces 44, 45, it will be appreciated that tip section 26b may be fixed and the root section 26a may be manipulated to align the opposing interfaces 44, 45. In another example, both the tip section 26b and the root section 26a may both be manipulated to align the opposing interfaces 44,45. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the Applicant’s general inventive concept.

Claims

1. A method for connecting a tip section (26a) to a root section (26b) to form a wind turbine blade (26), comprising: supporting the root section (26a) on a root bed (62), the root section (26a) having a root section interface (44); supporting the tip section (26b) on a fixed tip bed (68), the tip section (26b) having a tip section interface (46) spaced apart from and facing the root section interface (44), the tip bed (68) having an adjustable first tip support (70) having a first height and an adjustable second tip support (72) having a second height; providing a rail (96) extending in a longitudinal direction of the blade (26) between the tip section interface (46) and the root section interface (44); providing a movable trolley (102) associated with said rail (96); coupling said tip section (26b) to said trolley (102) and moving the tip section (26b) towards the root section (26a) by moving the trolley (102) along said rail (96) until the tip section interface (46) is a predetermined distance (D) from the root section interface (44); adjusting at least one of the first and second heights of the first and second tip supports (70, 72), respectively, to align the tip section interface (46) with the root section interface (44); and once aligned, connecting the tip section (26b) to the root section (26a) to form a connection joint (28).

2. The method of claim 1 , wherein adjusting the first height or the second height of the first and second tip supports (70, 72), respectively, includes causing the tip section interface (26b) to be generally parallel to the root section interface (26a).

3. The method of any of the preceding claims, wherein adjusting at least one of the first and second heights of the first and second tip supports (70, 72), respectively, includes adjusting both the first and second heights.

4. The method of any of the preceding claims, wherein adjusting at least one of the first and second heights of the first and second tip supports (70, 72), respectively, includes raising or lowering the tip section (26b) as a whole. 5. The method of any of the preceding claims, wherein adjusting at least one of the first and second heights of the first and second tip supports (70, 72), respectively, includes rotating the tip section (26b) about an axis perpendicular to a longitudinal axis of the tip section (26b).

6. The method of any of the preceding claims, wherein adjusting at least one of the first and second heights of the first and second tip supports (70, 72), respectively, includes rotating the tip section (26b) about a longitudinal axis of the tip section (26b).

7. The method of any of the preceding claims, wherein the first tip support (70) and the second tip support (72) are independently adjustable.

8. The method of claim 7, wherein the first tip support (70) has two independently vertically adjustable tip supports and the second tip support (72) has two independently vertically adjustable tip supports.

9. The method of any of the preceding claims, wherein said rail (96) extends between first and second rail supports (98, 100).

10. The method of claim 1 , further comprising using a winch (108) to move the trolley (102) along the rail (96) and pull the tip section (26b) towards the root section (26a).

11. The method of claim 1 or 10, further comprising positioning a stop block (106) on the rail (96) to stop the movement of the trolley (102) along the rail (96) such that the tip section interface (46) is at the predetermined distance from the root section interface (44).

12. The method of claim 1 or 11 , wherein moving the tip section (26b) towards the root section (26a) includes moving the tip section (26b) until the tip section interface (46) abuts the root section interface (44).

13. The method of any of the preceding claims, wherein said rail (96) forms a bridge extending from beneath the root section interface (44) to beneath the tip section interface (46).

14. The method of any of the preceding claims, wherein the tip section interface (46) and the root section interface (44) each include a plurality of threaded openings

(48), and wherein connecting the tip section (26b) to the root section (26a) includes inserting a first end of a threaded rod (50) into the threaded openings (48) of the root section (26a) and inserting a second end of the threaded rod (50) into corresponding threaded openings (48) of the tip section (26b).

15. The method of any of the preceding claims, wherein said rail (96) is in a fixed relation to said tip bed (68) and wherein said trolley (102) is movable in relation to said rail (96) and in relation to said tip bed (68).