Methods for installing wind turbines and methods for installing blades on wind turbines and wind turbines
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-01-30
- Publication Date
- 2026-08-13
Smart Images
Figure DK2026060005_13082026_PF_FP_ABST
Abstract
Description
[0001] METHODS FOR INSTALLING WIND TURBINES AND METHODS FOR INSTALLING BLADES ON WIND TURBINES AND WIND TURBINES
[0002] Technical Field
[0003] The invention relates generally to wind turbine installation, and more particularly to methods of installing rotors and blades on wind turbines.
[0004]
[0005] Wind turbines are used to produce electrical energy using a renewable resource and without combusting fossil fuels. A wind turbine converts kinetic wind energy into mechanical energy and then subsequently converts the mechanical energy into electrical energy. A common type of wind turbine is the single rotor upwind horizontal-axis wind turbine (HAWT). An exemplary single-rotor HAWT includes a tower, a nacelle located at the apex of the tower, and a single rotor having a central hub and one or more blades (e.g., three blades) mounted to the hub and extending radially therefrom. The rotor is supported by the nacelle and positioned at the front of the nacelle so that the rotor faces into the wind upstream of its supporting tower. The rotor may be coupled either directly or indirectly with a generator housed inside the nacelle and configured to convert the mechanical rotation of the rotor to electrical energy.
[0006] Wind turbine manufacturers continually strive to design and manufacture wind turbines with improved power production. The design of the wind turbine plays a significant role in the generated power output from wind. For example, energy obtained from the wind is proportional to the sweep area of the wind turbine blades. For single-rotor HAWTs, the sweep area may be increased by using longer wind turbine blades. The longer the blades, the larger the area that is traced by the blade tips. This translates to more energy extraction from the wind. However, the length, maximum chord length and root diameter of a wind turbine blade for a particular wind turbine is limited by several design factors.
[0007] As an exemplary limit, blade mass and root diameter increase with blade length. Each of these physical characteristics pose significant design challenges. For one, reliably supporting an increasingly heavier wind turbine blade at its attachment pointat the rotor becomes a limiting factor. The increased loading at the root magnifies fatigue at this location during rotation of the rotor and during yaw motion of the rotor when the wind turbine is operational. Transportation of the blades from a manufacturing location to site installation is also a challenge as increasing blade length, root diameter, and weight make transportation more challenging.
[0008] One design solution that permits increased blade length is to support the wind turbine blades during wind turbine operation with cables. Cable supported blades may be relatively longer than a blade without cable support. Wind turbines utilizing rotors that are supported by cabling may be referred to as a “cable-supported rotor” or “cable-stayed rotor.” Specifically, a webbing of cables extends to and between adjacent blades. With the aid of cables, the blades are capable of being proportionally longer while addressing the design problems identified above. In this way, cable supported rotors may be utilized to increase the sweep area of the blades to produce more energy from the wind. Longer blades may be assemblies of multiple parts or lengthwise sections. Where a blade is constructed of two lengthwise sections, the blade is often referred to as a “two-part blade” or “split blade.” The overall length of a split blade may include the sum of lengths of a main or inner blade section and a tip or outer blade section.
[0009] During installation of a wind turbine having a cable-supported rotor, the wind turbine blades are installed on the central hub and following installation of each blade, the cables are installed. Technicians first assemble the split blades and then use a crane to lift each assembled blade to the central hub. Often, the installation position for each blade is with a point of blade attachment on the central hub positioned at a three o’clock position. The assembled wind turbine blade is lifted in a horizontal orientation and attached to the central hub at the three o’clock position.
[0010] After the first blade is coupled to the central hub, the central hub and the single, installed blade are rotated counterclockwise. By this rotation, the technicians position the central hub to receive the next assembled blade at the three o’clock position. The process of rotation and attachment is repeated for each wind turbineblade. This technique may be referred to as horizontal single-blade installation (SBI).
[0011] The cables for supporting the individual blades are then installed. In that regard, individual cables that are to be used to support the blades may be released from a temporarily secured position on the blades and / or central rotor. Once released, technicians may complete all cable connections between the blades and, optionally, the central hub and then tension the cables whereby the wind turbine blades are supported by the cables.
[0012] While SBI and cable installation techniques are generally successful, wind turbine manufacturers seek improved installation techniques while overcoming current design limitations including solutions for installing blades at minimal cost.
[0013]
[0014] To further these goals, a method for installing a wind turbine is disclosed. The wind turbine is preferably a single-rotor HAWT. In one embodiment, there is a method for installing a wind turbine having a plurality of wind turbine blades coupled to a rotor hub. Each of the plurality of wind turbine blades is a split blade. An inner blade section is coupled to the rotor hub, and an outer blade section is coupled to the inner blade section at an interface bracket. The plurality of wind turbine blades is supported by a cable system which includes a plurality of cable assemblies. The method includes assembling an inner rotor subassembly including coupling a first inner blade section to a rotor hub, coupling a second inner blade section to the rotor hub, and coupling a third inner blade section to the rotor hub. The method further includes assembling at least a portion of the cable system on the inner rotor subassembly including coupling a first cable assembly of the plurality of cable assemblies to each of the first inner blade section and the second inner blade section and coupling a second cable assembly of the plurality of cable assemblies to each of the second inner blade section and to the third inner blade section. The method further includes rotating the inner rotor assembly on a main shaft coupled to the rotor hub. After rotating the inner rotor assembly, the method includes coupling a first outer blade section to the first inner blade section, coupling a second outer bladesection to the second inner blade section, and coupling a third outer blade section to the third inner blade section.
[0015] In one embodiment, the plurality of wind turbine blades consists of three wind turbine blades.
[0016] In one embodiment, during assembling the inner rotor subassembly, the inner rotor subassembly is proximate a level of a foundation of a wind turbine tower of the wind turbine.
[0017] In one embodiment, during assembling the inner rotor subassembly, the inner rotor subassembly is assembled on a support fixture resting on the ground.
[0018] In one embodiment, assembling the at least a portion of the cable system includes temporarily securing one or more cables of a third cable assembly of the plurality of cable assemblies to one or both the third inner blade section and the rotor hub. In one embodiment, after rotating the inner rotor subassembly, the method further includes releasing the temporarily secured one or more cables of the third cable assembly and coupling the released one or more cables together to form the third cable assembly.
[0019] In one embodiment, during assembling at least a portion of the cable system, a space between adjacent inner blade sections lacks a cable assembly of the cable system. In a related embodiment, before rotating the inner rotor subassembly, the method further includes coupling a hoist line and a main hook block of a crane to the rotor hub in the space between adjacent inner blade sections. In one embodiment, rotating the inner rotor subassembly includes orienting the inner rotor subassembly with the space between adjacent inner blade sections at the six o’clock position.
[0020] In one embodiment, before rotating the inner rotor subassembly, the method further includes lifting the inner rotor subassembly to an apex of a wind turbine tower and installing the inner rotor subassembly on the main shaft.In one embodiment, assembling the inner rotor subassembly includes lifting one or more of the inner blade sections to the rotor hub mounted on the main shaft.
[0021] In one embodiment, after coupling one or more of the outer blade sections, the method further includes rotating the inner rotor subassembly.
[0022] In one embodiment, after coupling the first outer blade section, the second outer blade section, and the third outer blade section, a specific power of the wind turbine is 250 W / m2or less.
[0023] In one embodiment, after coupling the first outer blade section, the second outer blade section, and the third outer blade section, the rotor has a rotor diameter of at least 150 m.
[0024] In one embodiment, during assembling at least a portion of the cable system, coupling the first cable assembly includes coupling the first cable assembly to the rotor hub and / or coupling the second cable assembly includes coupling the second cable assembly to the rotor hub.
[0025] According to another aspect of the invention, in an exemplary embodiment, there is a wind turbine including a wind turbine tower. An energy generating unit is atop the wind turbine tower. The energy generating unit has a plurality of wind turbine blades coupled to a rotor hub. Each of the plurality of wind turbine blades is a split blade defining an inner blade section coupled to the rotor hub and an outer blade section coupled to the inner blade section. The plurality of wind turbine blades is supported by a cable system. The cable system includes a plurality of cable assemblies including (i) a first cable assembly of the plurality of cable assemblies coupled to each of the first inner blade section and the second inner blade section; (ii) a second cable assembly of the plurality of cable assemblies coupled to each of the second inner blade section and to the third inner blade section; and (iii) a third cable assembly of the plurality of cable assemblies coupled to each of the third inner blade section and to the first inner blade section. A specific power of the wind turbine (10) is 250 W / m2or less.In one embodiment of the wind turbine, the plurality of wind turbine blades defines a rotor diameter of at least 150 m.
[0026] In one embodiment of the wind turbine, each of the cable assemblies is coupled to the rotor hub.
[0027] Brief Description of the Drawings
[0028] 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.
[0029] Fig. 1 is an elevation view of a cable-supported rotor wind turbine with a plurality of blades, each blade being a split-blade.
[0030] Fig. 1 A is an enlarged view of a rotor hub of the wind turbine shown in Fig. 1.
[0031] Fig. 2 is a partial perspective view of a wind turbine during installation with a portion of the rotor partially assembled.
[0032] Fig. 3 is an elevation view of the wind turbine shown in Fig. 2 during lifting of a portion of the rotor.
[0033] Fig. 3A is an enlarged view of Fig. 3.
[0034] Fig. 4 is an elevation view of installation of a rotor to a main shaft at a top of a wind turbine tower.
[0035] Fig. 5 is an elevation view of the wind turbine following installation of the portion of the rotor to the main shaft shown in Fig. 4 and counterclockwise rotation of the rotor.Fig. 6 is an elevation view of the wind turbine during installation of cables to the portion of the rotor of Fig. 5.
[0036] Fig. 7 is an elevation view of the portion of the rotor of Fig. 6 during installation of an outer blade section.
[0037] Detailed Description
[0038] With reference to figures generally, embodiments of the invention include wind turbines and methods for installing wind turbines, particularly installing wind turbine blades on a rotor of a wind turbine. Embodiments of the invention are advantageous in that wind turbine blade installation is economically addressed while also permitting construction of wind turbine designs not before possible. More specifically, Applicant identified a problem with installation of wind turbines having a rotor with cable-supported blades, such as the exemplary wind turbine 10 shown in Fig. 1. Broadly, the identified problem is with the installation of longer wind turbine blades on wind turbines with low specific power. Specific power is the wind turbine’s rated power output divided by the rotor area. Thus, for a given energy generating unit, specific power decreases as the blade length increases. As referenced herein, low specific power means 250 W / m2or less.
[0039] Further, the lower the specific power of the wind turbine, the greater the capacity factor of the wind turbine. Capacity factor is the average power generated divided by the rated peak power. Higher capacity factor wind turbines produce more electrical power at low wind speeds and produce electrical power over longer periods of time. For at least these benefits, higher capacity factor wind turbines are desirable. However, lower specific power also leads to a gearbox of relatively lower torque capacity and since the gearbox is used to turn the rotor during installation, this limits the imbalance of the rotor that can be turned using the gearbox. For full blade installation it may be impossible to safely turn a rotor with only one full blade installed. The installation method according to the invention may overcome this limitation in low specific power wind turbines by having a more balanced turbine during rotation of the rotor during installation.Cable-supported rotor wind turbines are advantageous in these markets, because they are generally characterized by having blades that are capable of being relatively longer than unsupported blades. Longer blades are possible because the rotors are cable supported. Cable supported rotor wind turbines may then be more adaptable to increasing the sweep area and thus lowering the specific power for a selected turbine. As an example, as referenced herein, lower specific power wind turbines have rotor diameters of at least 150 m or blade lengths of at least 75 m. Blade length is only one factor in specifying the design of a low specific power wind turbine.
[0040] Integral to low specific power wind turbine design is selection of an appropriate generator. Typically, the generator is coupled to the rotor via a drive train. The generator and drive train are selected based on a desired electrical production efficiency at a predetermined wind speed. For cost-effective electrical production efficiency at low wind speeds, wind turbine designers generally specify generators and drivetrains that have lower rated powers. However, generators / drive trains having lower rated power are characterized by being lighter duty, meaning that they are lighter in mass so that they rotate and maintain rotation at lower wind speeds. These components include lighter duty gear boxes and turner gears. Less mass in the generator and linked gear box enables low specific power.
[0041] While installation of longer blades presents significant installation challenges, Applicant identified that the blade installation problem is exacerbated by a combination of longer blades being installed on lower rated power generators and gear boxes, including turner gears. In view of the above, the identified problem is more specifically one of rotating an unbalanced rotor during blade installation on a rotor hub coupled to a generator and gear box, including turner gear, designed for low specific power generation.
[0042] Further in that regard, during blade installation, there is a period of time in which the rotor has one or two blades. That is, there is a time in which all blades have not been installed. With one or even two blades of three or more total blades installed on the central hub, the rotor is unbalanced. The unbalanced rotor is due to the massof the wind turbine blade extending from the rotor hub on only one side of the rotor hub.
[0043] Rotating a rotor during blade installation is accomplished with a turner gear. The turner gear may be coupled to a generator, or the turner gear may be directly connected to the generator without an intervening gear box. In either case, according to SBI (described above), the technicians operate the turner gear to properly position the installed blade so that the rotor hub is positioned to receive the next wind turbine blade. To rotate the unbalanced mass of the installed wind turbine blade coupled to the rotor hub, the turner gear must be able to withstand a predetermined amount of torque from the unbalanced mass of the installed blade(s) on the rotor hub. For comparison, the torque required to rotate the unbalance rotor exceeds the torque required to rotate a fully assembled rotor. Wind loading during installation on the installed blade may add to the torque load from the mass of the installed blade(s).
[0044] A problem occurs when the amount of torque needed for rotation of an unbalanced rotor exceeds a design torque limit of the turner gear and / or gear box of the specified lower rated power generator. SBI therefore is limiting and / or problematic, because the turner gear and / or gear box of a drive train for an energy generating unit specified for a lower rated power may not be capable of bearing the torque required to rotate a partially assembled rotor having blades longer (i.e., greater mass) than a predetermined length installed. That is, there is some blade length (i.e., mass) and wind load threshold at which SBI is not usable for low specific power wind turbines. In contrast to SBI, embodiments of the invention enable relatively longer and / or more massive blades to be installed on a wind turbine designed for a specific power, for example, of 250 W / m2or less and by way of further example, of 200 W / m2or less. Stated another way, according to embodiments of the invention, it is not necessary to redesign the generator, gear box, or turner gear to withstand torque from the unbalanced loading on a partially assembled rotor that occurs during installation. While embodiments of the invention are described with respect to an initial blade installation, embodiments may also be applicable to a blade retrofit when windturbine blades are removed from the rotor hub and replaced with new or refurbished blades, which may be longer than previously used for the wind turbine.
[0045] To that and other ends, an exemplary wind turbine 10 is shown in Fig. 1. The wind turbine 10 includes a tower 12 and an energy generating unit 14 (including a nacelle) disposed at the apex of the tower 12. The 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, anchor cage, 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 tower 12 supports the weight of the energy generating unit 14 and operates to elevate the energy generating unit 14 to a height above ground level or sea level at which faster moving air currents of lower turbulence are typically found.
[0046] In that regard, the energy generating unit 14 transforms the energy of the wind into electrical energy. The energy generating unit 14 typically includes a housing or nacelle 20, a rotor 22 having a rotor hub 24, and wind turbine blades 26a, 26b, 26c (e.g., three blades) mounted to the rotor hub 24 and extending radially therefrom. The energy generating unit 14 includes a drive train with a generator (not shown) for converting mechanical energy into electrical energy, optionally via a gear arrangement (not shown). The drive train (not shown) includes a main shaft, a gear box, including a turner gear, by which the rotor hub 24 is connected to the generator. A substantial portion of the drive train may be positioned inside of the nacelle 20 of the wind turbine 10. In addition to the energy generating unit 14, the nacelle 20 typically houses miscellaneous components required for converting wind energy into electrical energy and various components needed to maintain, operate, control, and optimize the performance of the wind turbine 10.
[0047] The wind turbine blades 26a, 26b, 26c are configured to interact with the wind. During operation, the wind produces lift and causes the rotor 22 to rotate. Rotation defines a sweep area of the wind turbine blades 26a, 26b, 26c. The energy generating unit 14 generates power from the wind that passes through the sweptarea of the rotor 22. Prior to operation, each of the wind blades 26a, 26b, 26c are installed as is described below.
[0048] With continued reference to Fig. 1, during operation, wind turbine blades 26a, 26b, 26c are supported by a cable system 30, which carries some of the static and dynamic loads on the rotor 22. In essence, the cable system 30 causes the wind turbine blades 26a, 26b, 26c to mutually support each other. For example, edgewise loads and / or flapwise loads are shared among the wind turbine blades 26a, 26b, 26c via the cable system 30.
[0049] In Figs. 1 and 1A, the exemplary cable system 30 includes three cable assemblies 32a, 32b, 32c, one cable assembly 32a, 32b, 32c, is shared between any two adjacent wind turbine blades 26a, 26b, 26c. As a result, each cable assembly 32a, 32b, 32c is coupled to the rotor 22 at three connections. One connection of each cable assembly 32a, 32b, 32c is at the rotor hub 24 and one connection of each cable assembly 32a, 32b, 32c is at each of two adjacent wind turbine blades 26a, 26b, 26c, for example, at a respective interface bracket 34a, 34b, 34c. That is, individual ones of the cable assemblies 32a, 32b, 32c are coupled to and between adjacent wind turbine blades 26a, 26b, 26c and to the rotor hub 24. As shown, each individual cable assembly 32a, 32b, 32c forms a Y-shaped cable configuration between adjacent wind turbine blades 26a, 26b, 26c and rotor hub 24. While a connection between each of the cable assemblies 32a, 32b, 32c and the rotor hub 24 is shown, embodiments of the invention are not limited to this configuration. Specifically, the connection between each of the cable assemblies 32a, 32b, 32c and the rotor hub 24 is optional. Alternatively, the cable assembly 30 may be formed by a cable of one or more parts arranged directly between two adjacent blades without a direct cable to the rotor hub.
[0050] Although not shown, tension in the cable system 30 may be adjustable via a tensioning system contained in the rotor hub 24. For example, one or more of the cable assemblies 32a, 32b, 32c may be operably coupled to hydraulic cylinders 46a, 46b, 46c (see Fig. 1A) fluidically coupled to the hydraulic system. Hydraulic cylinders 46a, 46b 46c extend from the rotor hub 24. Movement of any single one ofthe hydraulic cylinders 46a, 46b, 46c increases or decreases tension in the corresponding cable assembly 32a, 32b, and / or 32c. Tension in each of the cable assemblies 32a, 32b, 32c may be adjusted by operation of a tensioning system as is described in one or both of PCT Application Nos. PCT / DK2021 / 050374 and PCT / DK2022 / 050051. Tensioning the cable assemblies 32a, 32b, and / or 32c may be independently achieved during installation of the blades 26a, 26b, 26c.
[0051] In the exemplary embodiment, each of the plurality of wind turbine blades 26a, 26b, 26c is a split blade. Each of wind turbine blades 26a, 26b, and 26c may have two or more lengthwise blade sections that are assembled end-to-end. Each blade section has a length that is less than a total length of the assembled blade. The blade sections may be manufactured separately and transported separately to the installation site of the wind turbine 10. When assembled end-to-end, the sections form the wind turbine blades 26a, 26b, 26c. As an example, and with reference to Fig. 1 , each blade 26a, 26b, 26c may include an inner blade section and an outer blade section coupled together via the interface bracket 34a, 34b, 34c.
[0052] With reference to blade 26a, for example, an inner blade section 36a is coupled to the rotor hub 24 at one end. The inner blade section 36a defines a root end 42a of the blade 26a. The interface bracket 34a is coupled to the end of the inner blade section 36a opposite the rotor hub 24 at a first split position 28a. An outer blade section 38a is coupled to the interface bracket 34a at a second split position 40a. The outer blade section 38a defines a tip 44a of the blade 26a.
[0053] Similarly, with reference to blade 26b, an inner blade section 36b is coupled to the rotor hub 24 at one end. The inner blade section 36b defines a root end 42b of the blade 26b. The interface bracket 34b is coupled to the end of the inner blade section 36b opposite the rotor hub 24 at a first split position 28b. An outer blade section 38b is coupled to the interface bracket 34b at a second split position 40b. The outer blade section 38b defines a tip 44b of the blade 26b. And, with reference to blade 26c, an inner blade section 36c is coupled to the rotor hub 24 at one end. The inner blade section 36c defines a root end 42c of the blade 26b. The interface bracket 34c is coupled to the end of the inner blade section 36c opposite the rotor hub 24 at afirst split position 28c. An outer blade section 38c is coupled to the interface bracket 34c at a second split position 40c. The outer blade section 38c defines a tip 44c of the blade 26c.
[0054] As shown, the interface brackets 34a, 34b, 34c join the inner blade sections 36a, 36b, 36c with the outer blade sections 38a, 38b, 38c. Each of the blade sections 36a-36c and 38a-38c is coupled by studs (not shown) to a respective interface bracket 34a, 34b, 34c. A joint is therefore formed at the interface brackets 34a, 34b, 34c, which couple the first split position 28a-c of the inner blade sections 36a-36c to the second split position 40a-c of the outer blade sections 38a, 38b, 38c. In the exemplary embodiment, the interface bracket 34a, 34b, 34c provides a lengthwise separation between the inner blade sections 36a, 36b, 36c and the outer blade sections 38a, 38b, 38c although the blades sections 36a-36c and 38a-38c are many times longer than the interface brackets 34a, 34b, 34c. Split blades are described in detail in one or both of commonly owned PCT Application Nos. PCT / DK2021 / 050374 and PCT / DK2022 / 050051 , which are incorporated by reference herein in their entireties. The connection point of the cable system 30 to each wind turbine blade 26a, 26b, 26c may be positioned outside of the blade itself at the interface bracket 34a, 34b, 34c. For example, a cable connection may extend outwardly from the interface bracket 34a, 34b, 34c and be available for connection to the cable system 30. Embodiments of the invention are not limited to specific connection location of the cable system to the blades 26a, 26b, 26c or rotor hub 24.
[0055] In view of the above, in the exemplary embodiment, each blade 26a, 26b, 26c is an assembly of three parts. For example, (i) the wind turbine blade 26a is an assembly of the inner blade section 36a, the interface bracket 34a, and the outer blade section 38a; (ii) the wind turbine blade 26b is an assembly of the inner blade section 36b, the interface bracket 34b, and the outer blade section 38b; and (iii) the wind turbine blade 26c is an assembly of the inner blade section 36c, the interface bracket 34c, and the outer blade section 38c. As shown, the cable system 30 is coupled to each of the interface brackets 34a, 34b, 34c. During operation of the wind turbine 10, the cable system 30 supports the wind turbine blades 26a, 26b, and 26c.Figs. 2-7 depict one exemplary embodiment for installing the cable-supported rotor 22 during construction of the wind turbine 10. With reference to Fig. 2, the wind turbine tower 12 is first constructed. One or more cranes 50, 52 may be utilized during that construction process and assembly of the remaining portions of the wind turbine 10. As examples, a large crane 50 is capable of elevating components to an apex of the tower 12, such as to the nacelle 20 on the tower 12. Another crane 52 may be an auxiliary crane for assembling the wind turbine 10.
[0056] With continued reference to Fig. 2, technicians assemble an inner rotor subassembly 60 on the ground near the foundation 16. In the exemplary embodiment, the inner rotor subassembly 60 is assembled on a support fixture 54, which rests on the ground proximate the tower 12. The exemplary inner rotor subassembly 60 includes inner blade sections 36a, 36b, 36c coupled to the rotor hub 24. Further, the inner rotor subassembly 60 lacks the outer blade sections 38a, 38b, 38c. While three inner blade sections 36a, 36b, 36c are shown, the exemplary process is also applicable to wind turbines having four or more blades with four or more inner blade sections, respectively.
[0057] In the exemplary embodiment in which the inner rotor subassembly 60 is assembled on the support fixture 54 positioned on the ground, a portion of the cable system 30 is secured to the inner blade sections 36a, 36b, 36c and, optionally, the rotor hub 24. The entirety of the cable system 30 is not fully installed while the inner rotor subassembly 60 is on the ground. Specifically, one of the cable assemblies 32a, 32b, 32c is not fully installed and so does not support the corresponding inner blade section 36a, 36b, 36c. In the exemplary embodiment, the cable assembly 32c is not fully installed. The lack of full installation of the cable assembly 32c leaves an open space in the Y-shaped space generally defined between any two adjacent inner blade sections 36a, 36b, 36c. This open space created by the lack of full installation of the cable assembly 32c is labelled 62 in Figs. 2 and 3.
[0058] More specifically, for example, with respect to assembly of the inner rotor subassembly 60, the cable assembly 32a is secured to inner blade sections 36a and 36b and rotor hub 24 at the hydraulic cylinder 46a, and the cable assembly 32b issecured to inner blade sections 36b and 36c and rotor hub 24 at the hydraulic cylinder 46b. Each of the installed cable assemblies 32a and 32b may be pretensioned with the corresponding hydraulic cylinder 46a, 46b sufficiently to reduce any slack in the cables. Pretensioning of the cable assemblies 32a and 32b may be to a level less than that required to support the blades 26a and 26b during operation of the wind turbine 10.
[0059] As shown in Fig. 2, the remaining cable assembly 32c may not be fully installed. For example, individual ones of the cables for remaining cable assembly 32c may be temporarily secured to the inner blade sections 36a and 36c and to the hydraulic cylinder 46c. The temporary secured, individual cables prevent the cables from swinging freely during lifting and installation of the inner rotor subassembly 60, described below. Technicians are able to free the individual cables from their storage locations and connect them to one another after installation of the inner rotor subassembly 60. In the exemplary embodiment, the temporarily secured individual cables do not form the cable assembly 32c.
[0060] The lack of complete installation of the cable assembly 32c leaves the Y-shaped space 62 between the inner blade sections 36a and 36c open and leaves the inner blade sections 36a and 36c without tension between them. This open Y-shaped space 62 is then utilized to attach the inner rotor subassembly 60 to the crane 50. While a specific order of assembly of the inner blade sections 36a, 36b, 36c and then a portion of the cable system 30 is described, other assembly orders are contemplated. For example, two of the inner blade sections 36a, 36b may be coupled to the rotor hub 24 with a respective cable assembly 32a being installed between the installed inner blade sections 36a, 36b before another inner blade section 36b is installed. Embodiments of the invention are not limited to a specific order of assembly of the inner rotor subassembly 60 and cable system 30. However, assembling a majority of the cable system 30 while the inner rotor subassembly 60 is on the ground is advantageous because it saves a significant amount of installation time where crane assistance is required.Referring to Figs. 2 and 3, the crane 50 is coupled to the inner rotor subassembly 60. In that regard, a hoist line 56 and a main hook 58 of the crane 50 are attached to the rotor hub 24 in the Y-shaped open space 62 between the inner blade section 36a and the inner blade section 36c. Alternatively, although not shown, the hoist line 56 is coupled to slings around the inner blade section 36a and the inner blade section 36c. The crane 50 then lifts the inner rotor subassembly 60 toward the nacelle 20 as is shown in Fig. 3. This is indicated by arrow 66. To that end, the main crane 50 carries the weight of the inner rotor subassembly 60. However, the auxiliary crane 52 may provide some support and may control rotation of the inner rotor subassembly 60 from a generally horizontal orientation during assembly on the support fixture 54 to a generally vertical orientation during lifting. Rotational motion from horizontal to vertical of the inner rotor subassembly 60 during initial lift-off from the support fixture 54 is shown by arrows 70.
[0061] In the exemplary embodiment shown, the crane 52 may include an L-shaped hook 72 removably coupled to the first split position 28b of the inner blade section 36b. As the main crane 52 lifts the inner rotor subassembly 60 from the fixture 54, the crane 52 may be used to control the rotation between horizontal and vertical reorientation of the inner rotor subassembly 60. At some initial lift height, the inner rotor subassembly 60 reaches an equilibrium, generally vertical orientation, at which point the inner rotor subassembly 60 may be lifted off the L-shaped hook 72 of the crane 52. This is shown generally in Fig. 3A. The inner rotor subassembly 60 is then lifted solely by the main crane 50 toward the nacelle 20. In this exemplary embodiment, a single lift of each of the rotor hub 24 and three inner blade sections 36a, 36b, 36c completes installation of the inner rotor subassembly 60 with a portion of the cable system 30 installed.
[0062] Referring to Fig. 4, the inner rotor subassembly 60 is secured to a main shaft (not shown) at the nacelle 20. As shown, the Y-shaped space 62 is open vertically upward. Stated another way, at installation on the main shaft, the inner rotor subassembly 60 is oriented with inner blade section 36a generally pointing to the ten o’clock position, the inner blade section 36c generally pointing to the two o’clock position, and the inner blade section 36b pointing to the six o’clock position. Oncethe inner rotor subassembly 60 is installed on the main shaft, the main hook block 58 of the crane 50 is disconnected from the rotor hub 24 and is removed from the Y-shaped space 62.
[0063] With the Y-shaped space 62 open, the remaining cable assembly 32c is assembled to complete the assembly of the cable system 30. For example, and with reference to Fig. 5, to complete the cable system 30, the inner rotor subassembly 60 is rotated to orient the open Y-shaped space 62 in a six o’clock position. The Y-shaped space 62 faces downward. Stated another way, after rotation, the inner rotor subassembly 60 is oriented with inner blade section 36a generally pointing to the four o’clock position, the inner blade section 36c generally pointing to the eight o’clock position, and the inner blade section 36b pointing to the twelve o’clock position. As an example, rotation may be 180° from the orientation shown in Fig. 4 to the orientation shown in Fig. 5. Advantageously, rotation of the inner rotor subassembly 60 is possible with a turner gear. Because the inner rotor subassembly 60 is balanced, rotation of the inner rotor subassembly 60 creates less stress on the turner gear and gearbox as compared to the stress on the turner gear and gearbox from torque required to rotate a single blade attached to the rotor hub 24. The torque necessary to rotate the inner rotor subassembly 60 is less than the torque required to rotate the rotor 24 shown in Fig. 1.
[0064] With reference to Fig. 6, in the exemplary embodiment, individual cables of the cable assembly 32c are then released from their storage locations (shown by arrows 80) on the inner blade sections 36a, on the inner blade section 36c, and on the hydraulic cylinder 46c. The individual cables are then assembled. As shown, technicians on a suspended platform 82 may be lowered from the rotor hub 24 to assemble the cable assembly 32c. Alternatively, although not shown, the platform may be a man-basket lifted by a crane or man-lift basket. The cable system 30 is then tensioned sufficiently to support the inner blade sections 36a, 36b, 36c. Advantageously, tensioning the cable system 30 reduces or eliminates movement of the split positions 28a, 28b, 28c, such as deflection from vortex shedding created by interaction of the inner blade sections 36a, 36b, 36c with wind. Tensioning the cable system 30 maybe in addition or as an alternative to existing fishnet solutions that reduce or eliminate vortex shedding during installation.
[0065] As shown, according to embodiments of the invention, none of the wind turbine blades 26a, 26b, 26c is fully assembled and then attached to the rotor hub 24 according to SBI, as explained above. Rather, portions (e.g., inner blade sections 36a, 36b, 36c) of each of the wind turbine blades 26a, 26b, 26c are first attached to the rotor hub 24 and the cable system 30 is assembled to the portions of the assembled wind turbine blades 26a, 26b, 26c. The inner rotor subassembly 60 is then lifted and secured to a main shaft at the nacelle 20. By this order of assembly, rotation of the inner rotor subassembly 60 is then possible. The cable system 30 also stabilizes the inner blade sections 36a, 36b, 36c against movement from wind. The cable system 30 facilitates installation of the outer blade sections 38a, 38b, 38c, described below.
[0066] As an alternative to assembly of the inner rotor subassembly 60 on the ground as shown in Fig. 2, the inner rotor subassembly 60 may be assembled at the height of the nacelle 20. Specifically, the rotor hub 24 without any inner blade sections 36a, 36b, 36c may be attached to the main shaft (not shown) at the nacelle 20. Individual ones of the inner blade sections 36a, 36b, 36c may be lifted and attached to the rotor hub 24. That is, one inner blade section 36a, 36b, 36c at a time is lifted to the rotor hub 24 and is attached.
[0067] Following the attachment of the inner blade section 36a, 36b, 36c, the partially assembled inner rotor subassembly 60 is rotated. It is anticipated that attaching one or two of the inner blade sections 36a, 36b, 36c to the rotor hub 24 does not cause undue torque (e.g., from an unbalanced assembly or from wind) on the turner gear or gear box. In this exemplary embodiment, four lifts (i.e. , one lift for each of the rotor hub 24 and three inner blade sections 36a, 36b, 36c) are required to assemble the inner rotor subassembly 60. Once each inner blade section 36a, 36b, 36c is assembled at the nacelle 20, the cable system 30 is coupled to the inner rotor subassembly 60. Other lifting combinations are possible. For example, the rotor hub 24 and one of the inner blade sections 36a, 36b, 36c attached to the rotor hub24 may be lifted and installed with the remaining inner blade sections being separately lifted and installed.
[0068] With the inner rotor subassembly 60 complete and referring to Fig. 7, the outer blade sections 38a, 38b, and 38c are coupled to their respective inner blade sections 36a, 36b, 36c. As an example, the inner rotor subassembly 60 is rotated from the position shown in Fig. 6 to a position in which the inner blade section 36a is at a three o’clock position. The outer blade section 38a is lifted into position in horizontal alignment with the inner blade section 36a. The second split position 40a of the outer blade section 38a is then engaged with the interface bracket 34a. The outer blade section 38a is bolted to the interface bracket 34a to complete installation of the blade 26a. Although not shown, this installation process including rotating the inner rotor subassembly 60, lifting the outer blade section 38b, 38c, and coupling the outer blade section 38b, 38c to the interface bracket 34b, 34c is repeated for each of the outer blade sections 38b and 38c. Tension in the cable system 30 may also be adjusted. Advantageously, during assembly of the outer blade sections 38a, 38b, and 38c, the cable system 30 reduces or eliminates movement of the first split positions 28a, 28b, 28c.
[0069] Embodiments of the invention are exemplified with a single-rotor HAWT but are similarly useful for a multi-rotor HAWT on which the method may be used for installing or retroffitting the wind turbine blades using the same steps and sequence as described above and thereby achieving the same advantages.
[0070] While the present invention has been illustrated by a description of various preferred embodiments and while these embodiments have been described in some 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. Thus, the various features of the invention may be used alone or in any combination depending on the needs and preferences of the user.
Claims
CLAIMS1. A method of installing a wind turbine (10) having a plurality of wind turbine blades (26a, 26b, 26c) coupled to a rotor hub (24), wherein each of the plurality of wind turbine blades (26a, 26b, 26c) is a split blade defining an inner blade section (36a, 36b, 36c) coupled to the rotor hub (24) and an outer blade section (38a, 38b, 38c) coupled to the inner blade section (36a, 36b, 36c), wherein the plurality of wind turbine blades (26a, 26b, 26c) is supported by a cable system (30), and wherein the cable system (30) includes a plurality of cable assemblies (32a, 32b, 32c), the method comprising:(A) assembling an inner rotor subassembly (60) comprising:(i) coupling a first inner blade section (36a) to a rotor hub (24);(ii) coupling a second inner blade section (36b) to the rotor hub (24); and (iii) coupling a third inner blade section (36c) to the rotor hub (24);(B) assembling at least a portion of the cable system (30) on the inner rotor subassembly (60), wherein assembling comprises:(i) coupling a first cable assembly (32a) of the plurality of cable assemblies (32a, 32b, 32c) to each of the first inner blade section (36a) and the second inner blade section (36b); and(ii) coupling a second cable assembly (32b) of the plurality of cable assemblies (32a, 32b, 32c) to each of the second inner blade section (36b) and to the third inner blade section (36c);after (A) assembling the inner rotor subassembly (60),(C) rotating the inner rotor assembly (60) on a main shaft coupled to the rotor hub (24); andafter (C) rotating the inner rotor subassembly (60),(D) coupling:(i) a first outer blade section (38a) to the first inner blade section (36a); (ii) a second outer blade section (38b) to the second inner blade section (36b); and(iii) a third outer blade section (38c) to the third inner blade section (36c).
2. The method of claim 1 , wherein the plurality of wind turbine blades (26a, 26b, 26b) consists of three wind turbine blades (26a, 26b, 26b).
3. The method of any preceding claim, wherein during (A) assembling the inner rotor subassembly (60), the inner rotor subassembly (60) is proximate a level of a foundation (16) of a wind turbine tower (12).
4. The method of any preceding claim, wherein during (A) assembling the inner rotor subassembly (60), the inner rotor subassembly (60) is assembled on a support fixture (54) resting on the ground.
5. The method of any preceding claim, wherein (B) assembling the at least a portion of the cable system (30) includes temporarily securing one or more cables of a third cable assembly (32c) of the plurality of cable assemblies (32a, 32b, 32c) to one of or both the third inner blade section (36c) and the rotor hub (24).
6. The method of claim 5, wherein after (C) rotating the inner rotor subassembly (60), the method further comprises:releasing the temporarily secured one or more cables of the third cable assembly (32c); andcoupling the released one or more cables together to form the third cable assembly (32c).
7. The method of any preceding claim, wherein during (B) assembling the at least a portion of the cable system (30), a space (62) between adjacent inner blade sections lacks a cable assembly of the cable system (30).
8. The method of claim 7, wherein before (C) rotating the inner rotor subassembly (60), coupling a hoist line (56) and a main hook block (58) of a crane (50) to the rotor hub (24) in the space (62) between adjacent inner blade sections.
9. The method of claim 8, wherein (C) rotating the inner rotor subassembly (60) includes orienting the inner rotor subassembly (60) with the space (62) between adjacent inner blade sections at a six o’clock position.
10. The method of any preceding claim, wherein before (C) rotating the inner rotor subassembly (60), the method further comprises:lifting the inner rotor subassembly (60) to an apex of a wind turbine tower (12); andinstalling the inner rotor subassembly (60) on the main shaft.
11. The method of claim 1 or claim 2, wherein (A) assembling the inner rotor subassembly (60) includes lifting one or more of the inner blade sections (36a, 36b, 36c) to the rotor hub (24) mounted on the main shaft.
12. The method of any preceding claim, wherein during (D) after coupling according to one or more of (D)(i), (D)(ii), and (D)(iii), the method further comprises:rotating the inner rotor subassembly (60).
13. The method of any preceding claim, wherein after (D) coupling the first outer blade section (38a), the second outer blade section (38b), and the third outer blade section (38c), a specific power of the wind turbine (10) is 250 W / m2or less.
14. The method of any preceding claim, wherein after (D) coupling the first outer blade section (38a), the second outer blade section (38b), and the third outer blade section (38c), the rotor (22) has a rotor diameter of at least 150 m.
15. The method of any preceding claim, wherein during (B) assembling, coupling the first cable assembly (32a) includes coupling the first cable assembly (32a) to the rotor hub (24), and / or coupling the second cable assembly (32b) includes coupling the second cable assembly (32b) to the rotor hub (24).
16. A wind turbine comprising:a wind turbine tower (12);an energy generating unit (14) atop the wind turbine tower (12), the energy generating unit (14) having a plurality of wind turbine blades (26a, 26b, 26c) coupled to a rotor hub (24),wherein each of the plurality of wind turbine blades (26a, 26b, 26c) is a split blade defining an inner blade section (36a, 36b, 36c) coupled to the rotor hub (24) and an outer blade section (38a, 38b, 38c) coupled to the inner blade section (36a, 36b, 36c),wherein the plurality of wind turbine blades (26a, 26b, 26c) is supported by a cable system (30), andwherein the cable system (30) includes a plurality of cable assemblies (32a, 32b, 32c) including:(i) a first cable assembly (32a) of the plurality of cable assemblies (32a, 32b, 32c) coupled to each of the first inner blade section (36a) and the second inner blade section (36b);(ii) a second cable assembly (32b) of the plurality of cable assemblies (32a, 32b, 32c) coupled to each of the second inner blade section (36b) and to the third inner blade section (36c); and(iii) a third cable assembly (32c) of the plurality of cable assemblies (32a, 32b, 32c) coupled to each of the third inner blade section (36c) and to the first inner blade section (36a),wherein a specific power of the wind turbine (10) is 250 W / m2or less.
17. The wind turbine of claim 16, wherein the plurality of wind turbine blades (26a, 26b, 26c) define a rotor diameter of at least 150 m.
18. The wind turbine of one of claim 16 or claim 17, wherein each of the cable assemblies (32a, 32b, 32c) is coupled to the rotor hub (24).