Assembly method and assembly system for a vibration damper of a wind power plant tower

Abstract

The invention relates to an assembly method for a vibration damper of a tower of a wind power plant, in which the vibration damper is switched into a transport state from a state of use. The vibration damper is connected to a structural component of the tower such that a damper mass of the vibration damper can be set in motion, during which movement the distance between the damper mass and a central axis of the tower varies. The vibration damper is switched into the transport state by tilting the vibration damper compared to the state of use. The invention also relates to an associated assembly system.

Claims

1. A dis-assembly method for a vibration damper of a tower of a wind turbine comprising: moving the vibration damper from an in-use state to a transport state; and subsequently removing the vibration damper from the tower wherein, the vibration damper comprises a damper mass mounted to a frame, the frame is connected to a structural component of the tower and in the in-use state the vibration damper projects into an interior of the tower, in the in-use state, the damper mass can be set in motion relative to the frame by a drive such that a distance between the damper mass and a center axis of the tower changes, and the step of moving the vibration damper includes tilting the vibration damper relative to the in-use state.

2. The dis-assembly method of claim 1, wherein a distance between the damper mass and an axis of rotation can be adjusted.

3. The dis-assembly method of claim 1, wherein a mass of the damper mass can be adjusted.

4. The dis-assembly method of claim 1, wherein the vibration damper comprises a housing part and a frame part which can pivot relative to the housing part and the step of moving the vibration damper comprises: pivoting the housing part relative to the frame part while the frame part is still connected to the structural component of the tower; supporting the housing part such that a weight of the vibration damper is at least partially transmitted via the housing part; and detaching the frame part from the structural component of the tower.

5. The dis-assembly method of claim 1, wherein the vibration damper is provided with rollers.

6. The dis-assembly method of claim 1, wherein the vibration damper is moved in the transport state by a service elevator of the tower to a foot of the tower.

7. The dis-assembly method of claim 1, wherein the vibration damper is connected to a tower segment while the tower segment is in a lying state.

8. The dis-assembly method of claim 7, wherein the tower segment comprises an assembly element for the vibration damper and a retaining point, opposite the assembly element, for a cable/chain hoist.

9. A dis-assembly method for a vibration damper of a tower of a wind turbine comprising: moving the vibration damper from an in-use state to a transport state; and subsequently removing the vibration damper from the tower wherein, the vibration damper comprises a first damper mass and a second damper mass mounted to a frame, the frame is connected to a structural component of the tower, in the in-use state, the first damper mass and the second damper mass can be set in motion along opposite circular paths relative to the frame by a drive such that a distance between the first and second damper masses and a center axis of the tower change, and the step of moving the vibration damper includes tilting the vibration damper relative to the in-use state.

10. The dis-assembly method of claim 9, wherein a distance between the first and second damper masses and an axis of rotation can be adjusted.

11. The dis-assembly method of claim 9, wherein a mass of the first and second damper masses can be adjusted.

12. The dis-assembly method of claim 9, wherein the vibration damper comprises a housing part and a frame part which can pivot relative to the housing part.

13. The dis-assembly method of claim 9, wherein the vibration damper is provided with rollers.

14. The dis-assembly method of claim 9, wherein the vibration damper is moved in the transport state by a service elevator of the tower to a foot of the tower.

15. The dis-assembly method of claim 9, wherein the vibration damper is connected to a tower segment while the tower segment is in a lying state.

16. The dis-assembly method of claim 15, wherein the tower segment comprises an assembly element for the vibration damper and a retaining point, opposite the assembly element, for a cable/chain hoist.

17. A dis-assembly method for a vibration damper of a tower of a wind turbine comprising: moving the vibration damper from an in-use state to a transport state; and subsequently removing the vibration damper from the tower wherein, the vibration damper comprises a damper mass mounted to a frame, the frame is connected to a structural component of the tower, in the in-use state, the damper mass can be set in motion relative to the frame by a drive such that a distance between the damper mass and a center axis of the tower changes, and the step of moving the vibration damper includes tilting the vibration damper relative to the in-use state over an angle of greater than 45°.

18. A dis-assembly method for a vibration damper of a tower of a wind turbine comprising: moving the vibration damper from an in-use state to a transport state; and subsequently removing the vibration damper from the tower wherein, the vibration damper comprises a damper mass mounted to a frame, the frame is connected to a structural component of the tower, in the in-use state, the damper mass can be set in motion relative to the frame by a drive such that a distance between the damper mass and a center axis of the tower changes, and the step of moving the vibration damper includes tilting the vibration damper relative to the in-use state and a tilt axis to which the vibration damper is tilted between the in-use state and the transport state encloses an angle of at least 45° with an axis of rotation of the damper mass.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described by way of example below with the aid of advantageous embodiments with reference to the attached drawings, in which:

(2) FIG. 1 shows a side view of a wind turbine;

(3) FIG. 2 shows a first intermediate state in the erection of the tower of the wind turbine from FIG. 1;

(4) FIG. 3 shows a second intermediate state in the erection of the tower of the wind turbine from FIG. 1;

(5) FIG. 4 shows a vibration damper according to the invention in the in-use state;

(6) FIG. 5 shows a schematic representation of the functioning of the vibration damper from FIG. 4;

(7) FIG. 6 shows the vibration damper from FIG. 4 in the transport state;

(8) FIG. 7 shows the vibration damper according to FIG. 6 from a different perspective;

(9) FIG. 8 shows a different embodiment of a vibration damper according to the invention in the transport state;

(10) FIGS. 9-12 show multiple steps in the transition between the in-use state and the transport state of the vibration damper according to the invention.

DETAILED DESCRIPTION

(11) In a wind turbine shown in FIG. 1, a nacelle 14 is arranged rotatably on a tower 15. The nacelle carries a rotor 16 which is set in rotation by the wind. The rotor 16 drives a generator via a rotor shaft in order to produce electrical energy. The electrical energy is conveyed via a converter and a transformer into a grid that is internal to the wind farm and is fed from there into an electrical transmission grid.

(12) When such a wind turbine is erected, the tower 15 is first constructed by a plurality of tower segments 17 being arranged one on top of the other. The tower 15 is designed such that it stands stably without excessive vibration when the weight of the nacelle 14 bears on the upper end of the tower 15. In the intermediate state in which the tower stands without the upper end bearing a great weight, there is a risk that the tower 15 is caused to vibrate. According to the invention, a vibration damper 19 is arranged in the topmost tower segment 18 of the tower 15 and is designed to damp the vibration of the tower 15 such that the tower 15 is protected from excessive vibration even when the nacelle 14 is not present.

(13) The fundamental principle of the vibration damper 19 is shown in FIG. 4. The vibration damper 19 is an active system and consists of two excentrically mounted revolving and counter-revolving damper masses 20 (unbalanced masses) which are each driven by a motor (or a motor and a gearbox) and are maintained at a constant distance from a common axis of rotation 22 via a guide arm 21. The planes in which the two damper masses 20 move lie parallel to each other. The forces caused by the movement of the damper masses 20 are used to damp the vortex-induced tower vibration. Given a constant rotational speed w of the damper masses 20, a harmonic damping force F.sub.c results with the amplitude
F.sub.c=2.Math.m.sub.c.Math.Γ.sub.c.Math.ω.sup.2.
m.sub.c here designates the mass of a damper mass 20 and Γ.sub.c the radial distance between the damper mass 20 and the axis of rotation 22.

(14) According to FIG. 4, the tower vibration is measured by sensors 23 and the direction and frequency of the vibration are identified in a control unit 24. Based on this, the control unit 24 calculates control variables for the electromotors 25 by means of which the rotational movement of the damper masses 20 is driven. The motor speed ω is in particular part of the control variables of the electromotors. The system works automatically once it has been put into operation. The distance between the damper masses 20 and the axis of rotation 22 can lie, for example, between 0.5 m and 1 m, and the damper masses can, for example, have a mass between 50 kg and 150 kg.

(15) In the in-use state, the vibration damper 19 is, as shown in FIG. 3, connected to the tower wall and projects into the interior of the tower 15. The vibration damper 19 is assembled in the topmost tower segment 18 according to FIG. 2 whilst the topmost tower segment 18 is still lying on the ground. The topmost tower segment 18 is in a lying position in which the center axis 26 of the tower segment 18 is oriented essentially horizontally. The wall section to which the vibration damper 19 is connected points downward in the view in FIG. 2. A different angular position of the tower segment can also be expedient in practice.

(16) The vibration damper 19 is moved into the interior of the tower segment 18 by means of a ladder-guided roller carriage. The vibration damper 19 is lifted and brought into an upright position by means of a hoist which is fastened to a retaining point 27 such that it can be connected to the assembly elements 28 formed in the tower wall.

(17) After the vibration damper 19 is connected to the tower segment 19, the tower segment 18 is brought into an upright position by a large crane, lifted to the upper end of the tower 15, and placed on the already erected tower segments 17. When the tower segment 18 has been rigidly connected, the vibration damper 19 is connected to a power supply and hence brought into an active state. As soon as vibration occurs in the tower 15, the damper masses 20 are set in motion in order to damp the vibration.

(18) The tower 15 comprises a service elevator 29 with an elevator car 30 which travels between the foot of the tower and a platform 31 at the upper end of the tower 15. The vibration damper 19 is arranged and dimensioned such that it is possible to exit safely onto the platform 31 even when the vibration damper 19 is in operation and the damper masses 20 are moving. In particular, the circle 12 described by the movement of the damper masses 20 does not intersect the center axis 32 of the tower 15. The vibration damper 19 can optionally be provided with a protective cover by means of which unintended contact with the damper masses 20 is prevented.

(19) As soon as the head of the wind turbine is assembled with the nacelle 14 and the rotor 16, the vibration damper 19 is no longer required in order to maintain the tower 15 in a stable state without excessive vibration. The vibration damper 19 can be taken out of operation and disassembled.

(20) The steps in disassembling the vibration damper 19 are explained with the aid of FIGS. 9 to 12. FIG. 9 shows a state in which the vibration damper 19 is suspended from the assembly elements 28 of the tower segment 18 and in which the damper masses 20 and the guide arms 21 are disassembled. The aim is to place the vibration damper 19 on the platform 31 of the topmost tower segment 18 without the assistance of an external crane.

(21) As shown in FIG. 10, the vibration damper 19 comprises a housing part 34 and a frame part 33 which are mounted so that they can pivot about a pivot axis 35 relative to each other over an angle of tilt 11. The housing part 34 forms a housing inside which the technical components of the vibration damper 19, such as for example the motors 25 and the control unit 24, are accommodated. In FIG. 9, the pivot part 33 surrounds the housing part 34 on two sides and encloses the housing part 34 between them.

(22) By means of a pivoting movement, the housing part 34 can be pivoted into an upright position according to FIG. 10, whilst the frame part 33 is furthermore connected to the tower segment 18. The housing part 34 is provided at its lower end with rollers 36 which stand on the platform 31 when the housing part 34 has been brought into an upright position.

(23) When the housing part 34 stands stably on the platform 31, the connection between the frame part 33 and the assembly elements 28 of the tower segment 18 can be disconnected. A part of the housing part 33 adjacent to the assembly elements 28 is folded in such that the horizontal extent of the frame part 33 is less than the height of the housing part 34 (see FIG. 11). By means of a pivoting maneuver, the frame part 33 is tilted downward such that the housing part 34 is accommodated again inside the frame part 33. FIG. 12 shows the vibration damper 19 in the transport state. The vibration damper 19 can be pushed on the platform 31 into the elevator car 30 of the service elevator 29 and moved to the foot of the tower 15. The vibration damper 19 is then ready to be used when erecting another wind turbine.

(24) An embodiment is shown in FIGS. 6 and 7 in which the damper masses 20 and the guide arms 21 are detached from the frame of the vibration damper 19 only after the tilting maneuver. In the alternative embodiment according to FIG. 8, the guide arms 21 are equipped with a telescopic mechanism 37. The distance between the damper masses 20 and the axis of rotation 22 of the vibration damper 19 can be adjusted appropriately via the telescopic mechanism 37 depending on the use case.

(25) In the exemplary embodiment shown, the vibration damper 19 is configured such that in the transport state the height 38 is no greater than 180 cm, the width 39 is no greater than 80 cm, and the depth 40 is no greater than 45 cm. With these dimensions, the vibration damper 19 is suitable for transport in the elevator car 30 of the service elevator 29.

(26) As an alternative to transport in the service elevator 29, it is also possible to use an onboard crane arranged in the nacelle 14 in order to lower the vibration damper 19 down inside the tower 15. To do this, the onboard crane is positioned above the vibration damper 19, the vibration damper 19 is lifted slightly, a hatch in the platform 31 is opened, and the vibration damper 19 is lowered.

(27) According to a further alternative, the vibration damper 19 can be lifted into the interior of the nacelle 14 by the onboard crane and lowered through an opening in the floor of the nacelle 14, to the ground outside the tower 15.