Method of erecting a wind turbine

Abstract

The present invention provides a method of erecting a wind turbine on a wind turbine site. The wind turbine comprises a turbine tower and a nacelle. The method comprises the following steps: providing a plurality of tower sections being arrangeable upon each other in a vertical orientation in a tower structure to form the turbine tower, providing at least two damper units configured to dampen oscillations of the turbine tower, attaching one of the at least two damper units to one of the plurality of the tower sections on an outside thereof, and subsequently arranging said tower section in the tower structure, attaching a subsequent one of the at least two damper units to another one of the plurality of the tower sections on an outside thereof, and subsequently arranging said tower section in the tower structure, while the previous one of the at least two damper units is still attached to the previous one of the plurality of tower sections.

Claims

1. A method of erecting a wind turbine on a wind turbine site, the wind turbine comprising a turbine tower and a nacelle, the method comprising the following steps: providing a plurality of tower sections being arrangeable upon each other in a vertical orientation in a tower structure to form the turbine tower, providing at least two damper units configured to dampen oscillations of the turbine tower, attaching one of the at least two damper units to one of the plurality of the tower sections on an outside thereof, and subsequently arranging said tower section in the tower structure, attaching a subsequent one of the at least two damper units to another one of the plurality of the tower sections on an outside thereof, and subsequently arranging said tower section in the tower structure, while the previous one of the at least two damper units is still attached to the previous one of the plurality of tower sections.

2. The method according to claim 1, wherein the nacelle is arranged on top of the tower structure while at least one of the two damper units is attached to a tower section in the tower structure.

3. The method according to claim 1, further comprising a step of attaching a hoisting system to one of the at least two damper units and releasing said damper unit from the tower section to which it is attached in the tower structure and lowering said damper unit to the site.

4. The method according to claim 3, wherein the step of arranging one of the tower section in the tower structure comprises a step lifting the hoisting system and said tower section, arranging the tower section in the tower structure, detaching the tower section from the hoisting system, attaching the hoisting system to one of the damper units attached to another tower section in the tower structure, and lowering the hoisting system and said damper unit.

5. The method according to claim 4, wherein the step of attaching the hoisting system to one of the damper units in the tower structure is carried out before the step of detaching the tower section from the hoisting system.

6. The method according to claim 5, wherein the hoisting system comprising a tower section lifting sling and a damper unit lifting sling, the damper unit lifting sling have a length exceeding a height of said tower section, and wherein the step of attaching the hoisting system to said damper unit is carried out while the hoisting system is attached to an upper end of said tower section.

7. The method according to claim 1, wherein the step of attaching one of the at least two damper units to one of the plurality of the tower sections on an outside thereof, and subsequently arranging said tower section in the tower structure is carried out when a predetermined number of tower sections has been arranged in the tower structure.

8. The method according to claim 3, wherein the step of releasing one of the damper units from a tower section in the tower structure comprises a step of determining tension in the hoisting system, and based on the determined tension, to select a state where said damper unit can be released from said tower section.

9. The method according to claim 3, wherein the step of lowering a damper unit to the site further comprising a step of rotating said damper unit approximately 90 degrees before attaching said damper unit to a subsequent one of the plurality of tower sections.

10. The method according to claim 3, wherein the step of lowering a damper unit to the site further comprising a step of parking said damper unit on the site before attaching said damper unit to a subsequent one of the plurality of tower sections.

11. The method according to claim 1, wherein the step of attaching one of the at least two damper units to one of the plurality of the tower sections on an outside thereof comprises a step of providing at least one through hole in a wall of the tower section and fixing said damper unit to said tower section by a locking structure extending through the through hole.

12. The method according to claim 1, wherein the step of attaching one of the at least two damper units to one of the plurality of the tower sections on an outside thereof comprises a step of providing at least one shelf support on an outer surface of said tower section and fixing said damper unit to said tower section by engagement between the shelf support and a part of said damper unit.

13. The method according to claim 1, wherein the step of attaching one of the at least two damper units to one of the plurality of the tower sections on an outside thereof comprises a step of providing at least one pivoting structure between said damper unit and said tower section and aligning said damper by reorienting the pivoting structure relative to said tower section.

14. The method according to claim 1, wherein a damping frequency of at least one of the damper units is variable, and the method comprises a step of varying the damping frequency in dependency of the natural frequency of the tower structure.

15. The method according to claim 1, wherein each of the at least two damper units comprises: a damper unit structure adapted for attachment to the tower structure, a pendulum structure, a suspension arrangement for suspending the pendulum structure from the damper unit structure such that the pendulum structure is allowed to displace from a neutral position for the pendulum structure, the suspension arrangement comprising one or more wires for suspending the pendulum structure, a sensor adapted for measuring movements of the tower structure, and tuning means configured for adjusting the natural frequency of the suspended pendulum structure in response to measured movements of the tower structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be further described with reference to the drawings, in which:

(2) FIGS. 1A and 1B illustrate attachment of a damper unit to a tower section,

(3) FIG. 2 illustrates lifting of a tower section with a damper unit attached on the outside of thereof,

(4) FIG. 3 illustrates lowering of the hoisting system,

(5) FIGS. 4A and 4B illustrate lifting of a tower section, and subsequent lowering of a damper unit,

(6) FIG. 5 illustrates positioning of a tower section, and subsequent lowering of a damper unit,

(7) FIG. 6 illustrates lifting and positioning of a nacelle,

(8) FIG. 7 illustrates lowering of a damper unit,

(9) FIGS. 8A and 8B illustrate attachment of a damper unit to a tower section on ground,

(10) FIG. 9 illustrates different embodiments of attachment of a damper unit to a tower section,

(11) FIG. 10 illustrates a shelf support for a damper unit,

(12) FIG. 11 illustrates pivoting structures for alignment of a damper unit, and

(13) FIG. 12 illustrates rotation of a damper unit on ground.

DETAILED DESCRIPTION OF THE DRAWINGS

(14) It should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

(15) FIG. 1 illustrates steps of a method of erecting a wind turbine on a wind turbine site. The wind turbine comprising a turbine tower 1 (see FIG. 3) and a nacelle 2 (see FIG. 6). By the method a plurality of tower sections 3 is provided on the site. The tower sections 3 are arrangeable upon each other in a vertical orientation in a tower structure to form the turbine tower 1, where the “tower structure” is the part of the turbine tower 1 which has been erected at any time during the erection of the wind turbine.

(16) Furthermore, the method provides at least two damper units 4 configured to dampen oscillations of the turbine tower 1. FIGS. 1A and 1B illustrate attachment of one of the at least two damper units 4 to one of the plurality of the tower sections 3 on an outside thereof. In FIG. 1A, a damper unit 4 is attached to the tower section 3 on an outside thereof in a 12 o'clock position, a damper unit 4 in FIG. 1B is attached to a tower section 3 on an outside thereof in a 9 o'clock position as viewed from the right hand side of FIG. 1B.

(17) The damper unit 4 is attached to the tower section 3 by lowering (indicated by the arrow) the damper unit 4 towards the tower section 3 by use of a hoisting system 5.

(18) The tower section 3 while on the ground 6 is arranged on a support structure 7.

(19) FIG. 2 illustrates lifting of a tower section 3 with a damper unit 4 attached to an outside thereof. The tower section 3 is lifted by a hoisting system 5 and subsequently arranged on top of the tower structure on the uppermost tower section in the tower structure.

(20) FIG. 3 illustrates lowering of the hoisting system 5 after arranging a tower section 3 in the tower structure comprising three tower sections 3 forming the turbine tower 1. A damper unit 4 is attached to the tower section 3 which has being arranged before lowing the hoisting structure 5.

(21) FIGS. 4A and 4B illustrate lifting of a tower section 3′ (see FIG. 4A), and subsequent attachment of the hoisting system 5 to the damper unit 4 (see FIG. 4B) on the tower section 3 already in the tower structure. In the illustrated embodiment, the hoisting system 5 comprises a tower section lifting sling 5A and a damper unit lifting sling 5B. The damper unit lifting sling 5B has a length exceeding the height of the lifted tower section 3′. Consequently, the step of attaching the hoisting system 5 to a damper unit 4 can be carried out while the hoisting system 5 is attached to an upper end 3A of the lifted tower section 3′. Personnel who are assisting in the attachment of the lifted tower section 3′ to another tower section 3 already in the tower structure and to which tower section 3, the damper unit 4 is attached, are located on a platform (not shown) just below the top of the tower section 3 already in the tower structure. The damper unit 4 is accessible to the personnel that can reach the damper unit lifting sling 5B and attach it to the damper unit 4 safely before the lifted tower section 3′ is aligned with the tower structure.

(22) FIG. 5 illustrates the steps following attachment of the damper unit lifting sling 5B in to the damper unit 4 in FIG. 4B after positioning of a tower section 3′ with a damper unit 4′, and subsequent lowering of a damper unit 4. In the left part of FIG. 5, a tower section 3′ with a subsequent damper unit 4′ has just been arranged on top of another tower section 3 with a damper unit 4. The tower section lifting sling 5A is attached to the upper one of the tower sections 3′, whereas the damper unit lifting sling 5B is attached to the lower one of the damper units 4.

(23) In the centre of FIG. 5, the tower section lifting sling 5A has been released from the upper tower section 3′. The hoisting system 5 is lifted as indicated by the arrow to facilitate determination of tension in the hoisting system 5. By sensing tension in the hoisting system 5, it may be possible to detect whether the damping unit 4 is attached to the hoisting system 5 and fully supporting the weight of it.

(24) In the right part of FIG. 5, the lower damper unit 4 has been released from the lower tower section 3 and is lifted to the ground by the hoisting system 5 while being attached to the damper unit lifting sling 5B.

(25) FIG. 6 illustrates lifting and positioning of a nacelle 2 on top of the uppermost tower section 3 by use of a hoisting system 5. The above described tower section lifting sling 5A is attached to nacelle 2 to thereby arrange the nacelle 2. In the same lifting step, the damper unit lifting sling 5B is attached to the damper unit 4 attached to the uppermost tower section 3. As indicated by the arrow A, the width of the part of the nacelle 2 that extends outside the tower is smaller than the distance between the tower 3 and the attachment point to the damper 4 of the damper unit lifting sling 5B. Therefore, the damper unit 4 can be lifted without interference between the damper unit lifting sling 5B and the nacelle 2 during lifting of the damper unit 4.

(26) FIG. 7 illustrates lowering of a damper unit 4 after release of the damper unit 4 from the uppermost tower section 3. As illustrated by the arrows, the hoisting system 5 is lifted to facilitate determination of tension in the hoisting system 5 to ensure that the weight of the damper unit 4 is fully supported by the hoisting system 5. Then the damper unit 4 is released from the tower section 3 before it is lowered to the ground.

(27) FIGS. 8A and 8B illustrate attachment of a damper unit 4 to a tower section 3 in a horizontal orientation on the ground. The tower section 3 comprises a plurality of through holes 8 in a wall of the tower section to allow fixing of the damper unit 4 to the tower section 3 by a locking structure 9 extending through the through holes 8. The locking structure 9 forms part of the damper unit 4, whereby it can be inserted into the thought holes 8 when aligning the damper unit 4 with the tower section 3.

(28) FIG. 9 illustrates different embodiments of attachment of a damper unit 4 to a tower section 3. The tower section 3 comprises a plurality of through holes 8 in a wall of the tower section. In the left part of FIG. 9, a locking structure 9 extends through each of the through holes 8 to thereby fix the damper unit 4 to the tower section 3. In the centre par of FIG. 9, a manual guide pin 10 is used to guide the damper unit 4 into position. Subsequently to the positioning, a locking member (not shown) may be inserted into the through hole 8. In the right part of FIG. 9, a guiding line 11 is used to guide the damper unit 4 into position. A worker inside the tower section 3 may pull the guiding line 11 to position the damper unit 4, and subsequently to the positioning, a locking member (not shown) may be inserted into the through hole 8.

(29) The locking structure 9 is configured such that it can be released from the inside of the tower section 3. This makes is possible to release the damper unit 4 upon attachment of a subsequent tower section 3′, see FIG. 5, where the damper unit 4, and in particular any hoisting points or external connections to the tower, can no longer be reached by personnel from inside of the tower section 3.

(30) FIG. 10 illustrates a shelf support 12 for a damper unit 4. The shelf support 12 is attached to a wall of the tower section 3. In the illustrated embodiment, the shelf support 12 extends from the inside to the outside of the tower section 3, and comprises a reinforcement element 13 on the inside. The damper unit (not shown) is attached to the tower section by engagement between the shelf support 12 and a part of the damper unit.

(31) FIG. 11 illustrates pivoting structures 14 for alignment of a damper unit 4 with a tower section (not shown). The pivoting structures 14 are arranged between the damper unit 4 and the tower section. As illustrated, the pivoting structures 14 are provided as feet attached to the damping unit 4. The feet engage the outside surface of the tower section and pivots to automatically assume the best angle of contact. Consequently, the damping unit 4 may be aligned with tower sections of different size and/or different outer geometry.

(32) FIG. 12 illustrates rotation of a damper unit 4 on ground 6. The damper unit 4 is located in a support structure 15. When the damper unit 4 has to be rotated, the damper unit 4 is lifted together with the support structure 15 by the hoisting system 5. The rotational movement of the damper unit 4 may be carried out to prepare the damper unit 4 for attachment to the tower section according to the orientation of said tower section. For example attachment to a 3 o'clock, 9 o'clock or 12 o'clock position on the tower section before lifting the tower section with the damper unit 4 and arranging it in the tower structure.

(33) The support structure 15 has three support parts 16, 16′, 16″ and two attachment points 17′, 17″ for lifting slings 5′, 5″. To rotate the damper unit 4 from the orientation in the left part of FIG. 12 to that on the right part of FIG. 12, the lifting sling 5″ attached to the lifting point 17″ is tensioned until the damper unit 4 begin to rotate about the corner support part 16′. Upon further tensioning of the lifting sling 5′ the damper unit 4 will rotate 90 degrees to assume the position on the right part of FIG. 12. This provides for a safe and easy rotation of the damper unit 4.