Methods for removing and installing wind turbine blades

Abstract

A method of replacing or installing a wind turbine blade 30 comprises operating a winch (31, Fig 3A-H) to drive a support tool 1 along a tower 3 of the wind turbine (38, Fig 3A). A receptacle 20 throu

Description

The present invention relates to methods for removing and installing wind turbine blades at a wind turbine generator by use of a support tool. 5 BACKGROUND Energy production from wind power has increased substantially over the recent years, and there is continued high investments into wind energy power plants in order to meet future demands for energy security and emissions reductions. Land-based wind turbine technology is well-developed and contributes a notable part of io electric power generation capacity in many countries, and over the recent years there has been increasing interest both from academic research groups and industrial players into offshore wind technology, both bottom-fixed and floating systems. Publications which may be useful to understand the field of technology include WO 15 2020 / 167137. In all such plants, there is a need for systems and methods for safe and efficient installation, removal, replacement and / or servicing of components of a wind turbine generator or a wind turbine generator plant. The present disclosure has the objective to provide technology which provides advantages, or at least useful 20 alternatives, to the state of the art. SUMMARY In an embodiment, there is provided a method of removing a wind turbine blade, the method comprising: operating a winch to drive a support tool having a holder along 25 a tower of a wind turbine, the support tool having a receptacle through which the tower extends, positioning the blade in a vertical orientation proximate the tower, engaging the blade with the holder and holding the blade with the support tool, releasing the blade from a nacelle of the wind turbine while the blade is in the vertical orientation, lowering the support tool along the tower while holding the 13 1224 blade, operating the support tool to rotate the blade to a horizontal orientation subsequent to releasing the blade from the nacelle, and removing the blade from the support tool. In an embodiment, there is provided a method of installing a wind turbine blade on a 5 wind turbine using a support tool having a receptacle through which a tower of the wind turbine extends, the method comprising: positioning the blade in a horizontal orientation proximate the tower, mounting the blade in a holder of the support tool and holding the blade with the support tool, operating a winch to drive the support tool up the tower while holding the blade, operating the support tool to rotate the io blade to a vertical orientation, attaching the blade to a nacelle of the wind turbine while the blade is in the vertical orientation, releasing the blade from the holder, and driving the support tool down the tower. The receptacle is formed by two arm parts, each arm part having first and second longitudinally extendible and retractable arm members, and the method comprises is extending or retracting the arm members whilst lowering or driving the support tool. The step of operating the support tool to rotate the blade to the horizontal or vertical orientation may comprise operating a motor to rotate the holder via a pivotable or rotatable coupling on the support tool. The method may comprise rotating the blade while lowering the support tool or while 20 driving the support tool up the tower. The winch may be arranged on the tower, on a base adjacent the tower, or on the tool. The step of operating the winch to drive the support tool may comprise lifting the support tool by means of lifting member extending from the winch to a sheave or a 25 fixation at a top of the tower or at the nacelle. The detailed description below outlines further examples and embodiments. 13 1224 BRIEF DESCRIPTION OF THE DRAWINGS The above and other characteristics will become clear from the following description of illustrative, non-restrictive examples, with reference to the attached drawings, in which: 5 Figures 1 and 2 illustrate a support tool according to an example. Figures 3A-3H illustrate the use of a support tool in a wind turbine operation. DETAILED DESCRIPTION Figure 1 shows a support tool 1 for a wind turbine according to one example. The io support tool 1 comprises a guide part 2 having receptacle 20 for positioning a tower 3 of the wind turbine therein. The guide part 2 comprises a plurality of support members 21a-d facing the receptacle 20 and operable to engage the tower 3 when the support tool 1 is positioned relative to the tower 3 such that the tower 3 is positioned in the receptacle. In this example, the support members 21a-d comprises is rollers or wheels, however the support members 21a-d may in other examples be made up of belt drives, skid members, or the like. The receptacle 20 is defined by two arm parts 22a,b, each arm part 22a,b having first and second longitudinally extendible arm members 23a,b, 24a,b. The arm members 23a,b, 24a,b may, for example, be telescopic arms. In this example, as 20 indicated in the figures, the longitudinal extension or retraction of the arms 23a,b, 24a,b is effectuated by hydraulic cylinders, however any suitable actuator may be employed for this purpose. As illustrated in Fig. 1, the first arm members 23a,b are extendible in a first direction, illustrated by axis 25 and arrow 25’. By extending the first arm members 23a,b, the 25 width of the receptacle 20 can thus be adjusted. The second arm members 24a,b are extendible in a second direction, illustrated by axis 26 and arrow 26’. The second direction is perpendicular to the first direction 25. By extending the second arm members 24a,b, the depth of the receptacle 20 can thus be adjusted. The receptacle 20 is thereby adjustable to accommodate for various diameters of a wind 30 turbine tower 3. 13 1224 A tool part 4, described in further detail below, is fixed to the guide part 2 via a coupling 40. In this example, each of the arm members 23a,b, 24a,b is provided with one support member 21a-d which are arranged within the receptacle 20. Each of the support 5 members 21a-d is thereby movable with the respective arm member 23a,b, 24a,b. Alternatively, a different arrangement of the support members 21a-d can be used, for example providing one support member adjacent the coupling 40 together with support members 21b and 21d. In such an arrangement, the support tool 1 is supported against the tower 3 at three points and the extension of the arm members io 23a, 23b, 24a, 24b allows for adjustment capability to account for different diameters of the tower 3 whilst maintaining contact between the support members 21b, 21 d and the tower 3. Illustrated in Fig. 2, the support tool 1 may further comprise third and fourth arm parts which are longitudinally spaced from and generally parallel to arm members is 23a,b and 24a,b. The fourth arm part 27 is visible in Figure 2. Each of the third and fourth arm parts has first and second arm members which are each parallel to one of the first and second arm members 23a, 23b, 24a, 24b, and which are longitudinally extendible in the same way as arm members 23a,b and 24a,b. This may provide a more secure and stable connection to the tower 3. 20 In this example, the tool part 4 comprises a holder 42 for a wind turbine blade 30. The holder 42 can, for example, comprise one or more clamps operable to clamp and hold the blade 30, a receiver part, such as a frustoconical receiver, into which the blade 30 can be inserted such that the blade 30 is held by the holder 42, or another type of holding mechanism. 25 The tool part 4 may be connected to the guide part 2 via a pivotable or rotatable coupling 40, such that the pivotable or rotatable coupling 40 can permit or actively effectuate relative rotation between the guide part 2 and the tool part 4 about an axis 41 which is generally parallel to the second arm members 24a, 24b. The coupling 40 may be a swivel or the like, optionally having a brake or locking 30 mechanism, and the pivoting or rotation can be effected by external means. Alternatively, the coupling 40 may include or be directly connected to a motor which is able to rotate the tool part 4 relative to the guide part 2. 13 1224 Figures 3A-3H illustrate one example of the use of a tool 1 in a method of replacing a wind turbine blade 30. The wind turbine 38 comprises a tower 3 arranged on a base 32 and having a nacelle 39 at its upper end, with a plurality of blades 30 fixed thereto. As part of normal operations of the wind turbine 38, one or more of the 5 blades 30 may need to be replaced. As illustrated in Fig. 3A, the tool 1 described in relation to Figs. 1 and 2 may be placed on the tower 3 such that the tower 3 is positioned in the receptacle 20. The tool 1 may then be lifted up the tower 3 to an upper part thereof (Figs 3B and 3C). In this example, the tool 1 is lifted by means of a winch 31 having a lifting member (such as a rope or a wire) extending to a sheave io at the top of the tower 3 or at the nacelle 39. The winch 31 can be placed on the base 32. Optionally, the winch 31 can be placed on the tower 3, or on the tool 1 itself (in which case a sheave may not be needed, but the rope or wire can be fixed at the top part of the tower 3 or at the nacelle 39). Wind turbine towers 3 are typically tapered, their diameter decreasing from the is bottom of the tower 3 to the top. Therefore, in order to prevent significant horizontal movement of the receptacle 20 relative to the tower 3 as the tool 1 is lifted by means of a winch arrangement as described above, the actuators which are operable to adjust the length and width of the receptacle 20 may be operated to retract, i.e. decrease the length of each of the arm members 23a, 23b, 24a, 24b so that contact 20 between all the support members 21a-21d and the tower 3 is maintained at all time. This may be achieved by providing springs which apply a generally constant force to each arm member 23a, 23b, 24a, 24b to urge it to retract, thus ensuring that the support members 21a - 21 d are urged into contact with the tower 3 with a generally constant force as the tool 1 moves up or down the tower 3. The springs would be 25 configured to apply a force which is strong enough to retract the arm members 23a, 23b, 24a, 24b as the tool 1 is raised up the tower 3, but which is low enough, that the arm members 23a, 23b, 24a, 24b can extend as the tool 1 is lowered down the tower 3. The spring force could be provided by a pneumatic spring or a mechanical spring. 30 Alternatively, the extension and retraction of the arm members 23a, 23b, 24a, 24b could be driven by an actuator, operation of which is controlled by a controller which is operable to coordinate automatically the operation of the drive system for lifting 13 1224 the tool 1 up the tower 3, e.g. a drive motor for the winch 31. This coordination may be achieved by providing each of the support members 21a-21d with a pressure sensor which provides a pressure signal indicating the pressure on the support member 21a - 21 d, the sensors being connected to the controller so that the 5 controller can receive pressure signals from each pressure sensor. The controller may be configured to monitor the pressure signals received, and if any of the pressure signals indicate that the pressure on one or more of the pressure sensors has fallen below, to operate one or more of the actuators to retract one or more of the arm members 23a, 23b, 24a, 24b a predetermined level until the pressure io signals received from the pressure sensors indicate that the pressure on all the support members 21a-21d is substantially equal. Alternatively, if the angle of taper of the tower 3 is known, the controller could be programmed to automatically retract the first and second arm members 23a, 23b, 24a, 24b at a rate calculated based on the angle of taper and speed of lifting of the is tool 1. For example, if the tower 3 tapers such that its sides lie at an angle of a degrees to the vertical equally all the way around its diameter and along its length, and the tool 1 is lifted at a rate of X m / s, the rate of retraction of the arm members 23a, 23b, 24a, 24b would be set to 2X.tana m / s. Conversely, when the tool 1 is lowered, the actuators will be operated to extend the 20 arm members 23a, 23b, 24a, 24b to increase the depth and width of the receptacle 20. Where pressure sensors are used, the controller would be configured to extend the arm members 23a, 23b, 24a, 24b when the pressure signals received from the pressure sensors indicate that the pressure exerted on one or more of the support members 21a-21d exceeds a pre-determined level. 25 As illustrated in Fig. 3C, when the tool 1 is lifted to a position adjacent the blade 30, the tool 1 may engage the blade via the holder 42. The blade 30 may then be held by the tool 1, supported by the tower 3, and the blade 30 can be released from the nacelle 39, as illustrated in Fig. 3D. The tool 1 can then be lowered towards the base 32 to be removed from the tool 1. 30 The removal can be done by other equipment, such as a crane or other type of suitable machine therefor. For an offshore wind turbine 38, this may be a ship or a barge having such a crane or other equipment thereon. A new blade can be placed in the tool 1 and the new blade installed by a reversed operation equivalent to that described above, where the tool 1 is lifted with the new blade until in position adjacent the nacelle 39, whereupon the new blade can be fixed to the nacelle 39 and the tool 1 be lowered empty. 5 The blade 30 is advantageously engaged by the tool 1 and released from the nacelle 39 while in a substantially vertical orientation. The blade 30 may then be rotated by the tool 1, by means of the coupling 40, such that the blade 30 is provided in a horizontal orientation at or adjacent the base 32. The invention is not limited by the embodiments described above; reference should io be had to the appended claims. CM 13 1224

Claims

1. A method of removing a wind turbine blade (30), the method comprising: operating a winch (31) to drive a support tool (1) having a holder (42) along a tower (3) of a wind turbine (38), the support tool (1) having a5 receptacle (20) through which the tower (3) extends,positioning the blade (30) in a vertical orientation proximate the tower(3), engaging the blade (30) with the holder (42) and holding the blade with the support tool (1),io releasing the blade (30) from a nacelle (39) of the wind turbine (38)while the blade (30) is in the vertical orientation,lowering the support tool (1) along the tower (3) while holding the blade (30),operating the support tool (1) to rotate the blade (30) to a horizontalis orientation subsequent to releasing the blade (30) from the nacelle (39), andremoving the blade (30) from the support tool (1), wherein the receptacle (20) is formed by two arm parts (22a,b), each arm part (22a,b) having first and second longitudinally extendible and retractable arm members (23a,b, 24a,b), and wherein the method comprises20 extending the arm members (23a,b, 24a,b) whilst lowering the support tool(1)-2. The method of claim 1, wherein the step of operating the support tool (1) to rotate the blade (30) to the horizontal orientation comprises operating a25 motor to rotate the holder (42) via a pivotable or rotatable coupling (40) onthe support tool (1).

3. The method of claim 1 or 2, comprising rotating the blade (30) while lowering the support tool (1).

304. The method of any one of claims 1-3, wherein the winch (31) is arranged on the tower (3) or on a base (32) adjacent the tower (3).

5. The method of any one of claims 1-3, wherein the winch (31) is arranged on the support tool (1).

6. The method of claim 4 or 5, wherein the step of operating the winch (31) to5 drive the support tool (1) comprises lifting the support tool (1) by means oflifting member extending from the winch (31) to a sheave or a fixation at a top of the tower (3) or at the nacelle (39).

7. A method of installing a wind turbine blade (30) on a wind turbine (38) using io a support tool (1) having a receptacle (20) through which a tower (3) of thewind turbine (38) extends, the method comprising:positioning the blade (30) in a horizontal orientation proximate the tower (3),mounting the blade (30) in a holder (42) of the support tool (1) and15 holding the blade (30) with the support tool (1),operating a winch (31) to drive the support tool (1) up the tower (3)CM while holding the blade (30),1 operating the support tool (1) to rotate the blade (30) to a verticalCO orientation,1 20 attaching the blade (30) to a nacelle (39) of the wind turbine (38)while the blade (30) is in the vertical orientation,releasing the blade (30) from the holder (42), and driving the support tool (1) down the tower (3), wherein the receptacle (20) is formed by two arm parts (22a,b), each25 arm part (22a,b) having first and second longitudinally extendible andretractable arm members (23a,b, 24a,b), and wherein the method comprises retracting the arm members (23a,b, 24a,b) whilst driving the support tool (1).

8. The method of claim 7, wherein the step of operating the support tool (1) to30 rotate the blade (30) to the vertical orientation comprises operating a motorto rotate the holder (42) via a pivotable or rotatable coupling (40) on the support tool (1).

9. The method of claim 7 or 8, comprising rotating the blade (30) while driving the support tool (1) up the tower (3).

10. The method of any one of claims 7-9, wherein the winch (31) is arranged on 5 the tower (3) or on a base (32) adjacent the tower (3).

11. The method of any one of claims 7-9, wherein the winch (31) is arranged on the support tool (1).io 12. The method of claim 10 or 11, wherein the step of operating the winch (31) to drive the support tool (1) comprises lifting the support tool (1) by means of lifting member extending from the winch (31) to a sheave or a fixation at a top of the tower (3) or at the nacelle (39).CM

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