How to install a service lift on a multipart wind turbine tower

Abstract

A method is provided for installing a service lift (22) inside a wind turbine tower (12). The wind turbine tower (12) includes an upper tower section (32) configured to be connected to a lower tower section (30) to form the wind turbine tower (12). The method includes providing an upper tower stand (36) at a tower pre-assembly site (34) and installing a service lift (22) on the upper tower stand (36). The method includes connecting the upper tower section (30) of the wind turbine tower (12) to the upper tower stand (36) so that the upper tower section (30) is supported on the upper tower stand (36), and connecting the service lift (22) inside the upper tower stand (36) to the upper tower section (30) of the wind turbine tower (12) so that the service lift (22) can operate within the upper tower section (30).

Description

Technical Field

[0001] This application generally relates to wind turbines, and more specifically to the installation of service lifts in wind turbine towers assembled from one or more pre-assembled tower sections.

Background Art

[0002] Wind turbines are used to generate electrical energy using renewable resources without burning fossil fuels. Generally, wind turbines convert the kinetic energy from the wind into electricity. A horizontal-axis wind turbine includes a tower, a nacelle disposed at the top of the tower, and a rotor having a plurality of blades and supported within the nacelle by a shaft. The shaft directly or indirectly couples the rotor to a generator housed within the nacelle. As a result, when the wind rotates the blades, electrical energy is generated by the generator. For this purpose, wind turbines can be placed either on land (onshore) or in water (offshore).

[0003] In recent years, as the demand for electrical energy has increased, wind turbines have been developed in larger sizes to generate more electricity. In that regard, offshore wind turbines have gained popularity because they can utilize stronger and more consistent wind speeds than onshore turbines and can generate more electricity. However, the construction and installation of offshore wind turbines have several challenges, particularly including the transportation and assembly of large and heavy wind turbine components to the wind turbine site.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Offshore wind turbines are complex structures, and one of their key components is the tower, which can sometimes exceed 100 meters in height and weigh hundreds of tons. Due to their large size and weight, these towers present challenges in terms of pre-assembly, transportation, and installation. Typically, towers are fully assembled at the pre-assembly site and transported to the offshore site using seaplanes. However, limitations such as the weight-bearing capacity of temporary tower stands at the pre-assembly site make it impractical to assemble the largest wind turbine towers there. Assembling towers outside of the pre-assembly site presents several challenges. Specifically, the installation of certain tower components, such as service lifts, becomes more complex. In addition, the overall cost of labor and transportation for wind turbine installation increases. For example, one of the most labor-intensive installation tasks when installing a wind turbine tower is the installation of tower service lifts, which are used to transport personnel and parts within the tower during wind turbine installation, maintenance, and maintenance. For this purpose, in the largest wind turbine towers mentioned above, a significant portion of the service lift installation work may need to be carried out at locations other than the pre-assembly site, such as the sea, which further increases installation costs.

[0005] To address the challenge of assembling wind turbine towers at locations other than the pre-assembly site, there is a need for systems and methods that utilize pre-assembled tower sections to reduce the labor and installation time associated with assembling wind turbine towers at other locations. In this regard, there is a need for pre-assembled tower sections that can significantly reduce the labor and installation time required to install service lifts within the wind turbine tower at the wind turbine site. By pre-assembling the tower sections at the pre-assembly site, the installation of service lifts can be carried out more efficiently at another location, thereby reducing the overall labor and installation time required to assemble the tower for operation. This can lead to cost reductions and improved efficiency in the installation and maintenance of wind turbines. [Means for solving the problem]

[0006] According to a first aspect of the present invention, a method for installing a service lift within a wind turbine tower is disclosed. The wind turbine tower includes an upper tower section configured to be connected to a lower tower section to form a wind turbine tower. The method includes providing an upper tower stand at a tower pre-assembly site, providing a service lift on the upper tower stand, positioning the upper tower section of the wind turbine tower on the upper tower stand so that the upper tower section is supported on the upper tower stand, and connecting the service lift within the upper tower stand to the upper tower section of the wind turbine tower so that the service lift can operate within the upper tower section. The method further includes operating the service lift within the upper tower section of the wind turbine tower and fixing the service lift to the upper tower section at a position vertically separated from the upper tower stand for subsequent assembly of the wind turbine tower. For example, operating the service lift within the upper tower section of the wind turbine tower may include performing one or more operational tests (e.g., certification tests) to verify the proper operation of the service lift.

[0007] According to one embodiment of the present invention, the upper tower portion includes a lift wire assembly having a first fixed end and a second free end attached to the upper tower portion adjacent to its upper end. In this regard, operably connecting the service lift to the upper tower portion may include connecting the free end of the lift wire assembly to the upper tower stand and connecting the lift wire assembly to the service lift so that the service lift is movable along the lift wire assembly.

[0008] In one embodiment, the upper tower stand may include a temporary power supply. In this regard, the method may further include connecting the service lift to a temporary power supply in the upper tower stand so that the service lift can operate within the upper tower section. For example, connecting the service lift to a temporary power supply may include providing a temporary power cable and connecting the temporary power cable between the temporary power supply and the service lift.

[0009] According to another embodiment of the present invention, the upper tower portion of a wind turbine tower includes an upper power cable connected to the upper tower portion. The upper power cable may include a fixed cable portion and a movable cable portion connected by a cable interface to form the upper power cable. In this regard, the fixed cable portion may include a free end adjacent to the lower end of the upper tower portion. The movable cable portion may include a free end adjacent to the lower end of the upper tower portion. In this embodiment, the method may further include connecting the free end of the fixed cable portion to a temporary power source and connecting the free end of the movable cable portion to a service lift.

[0010] In a further embodiment, the upper tower portion may further include a pulley guide wire having a fixed end connected to the upper tower portion and a free end connected to the upper tower stand, and a pulley movably attached to the pulley guide wire. Thus, connecting the free end of the movable cable portion to the service lift may further include connecting the free end of the movable cable portion to the service lift so as to engage the movable pulley with the pulley guide wire.

[0011] According to one embodiment of the present invention, after fixing the service lift to the upper tower section, the method may include detaching the service lift within the upper tower section from the upper tower stand so that the service lift becomes inoperable within the upper tower section. For example, detaching the service lift from the upper tower stand may include detaching the free end of the lift wire assembly from the upper tower stand.

[0012] In one embodiment, disconnecting the service lift from the upper tower stand may further include disconnecting the service lift from the temporary power supply.

[0013] In another embodiment, disconnecting the service lift from the upper tower stand may include disconnecting the free end of the fixed cable portion of the upper power cable from the temporary power supply.

[0014] In yet another embodiment, disconnecting the service lift from the upper tower stand may include disconnecting the free end of the pulley guide wire from the upper tower stand.

[0015] According to one embodiment, the upper tower portion may include a plurality of tower sections, and securing the service lift to the upper tower portion may include securing the service lift to the upper tower portion at the joint between two adjacent tower sections of the plurality of tower sections.

[0016] According to another embodiment of the present invention, a lower tower stand can be provided at the tower pre-assembly site. The method may further include positioning the lower tower portion of a wind turbine tower on the lower tower stand so that the lower tower portion is supported on the lower tower stand. The lower tower portion may include a lower power cable having a fixed end adjacent to the lower end of the lower tower portion for connecting to a power box attached to the lower tower portion and a free end adjacent to the upper end of the lower tower portion for connecting to an upper power cable. The tower pre-assembly site may be on land, preferably on the shore.

[0017] A second aspect of the present invention discloses a method for assembling a wind turbine tower. This method includes installing a service lift on the wind turbine tower according to the first aspect described above at a tower pre-assembly site. This method further includes moving the lower tower portion from the tower pre-assembly site to a tower assembly site, moving the upper tower portion from the tower pre-assembly site to a tower assembly site, and connecting the upper tower portion to the lower tower portion to form a wind turbine tower.

[0018] For this purpose, in one embodiment, the tower assembly site may be mounted on a transport vessel such as an offshore installation ship.

[0019] A third aspect of the present invention discloses a method for installing a wind turbine tower at an offshore wind turbine installation site. This method includes assembling the wind turbine tower according to the second aspect described above. This method further includes connecting the wind turbine tower to an offshore foundation, connecting the first fixed end of the lower power cable to the power box of the lower tower portion of the wind turbine tower, which can be performed at the tower pre-assembly site, connecting the second free end of the lower power cable to the free end of the fixed cable portion of the upper power cable, connecting the free end of the lift wire assembly to the offshore foundation or the lower portion of the tower, connecting the free end of the pulley guide wire to the offshore foundation, and optionally connecting the free end of the movable cable running portion to a service lift.

[0020] According to one embodiment, the method may further include releasing a service lift from the upper tower portion of the wind turbine tower so that it can be operated within the wind turbine tower.

[0021] A fourth aspect of the present invention discloses a storage system for a wind turbine tower, including an upper tower section, a lower tower section, and a service lift. The storage system includes an upper tower stand supporting the upper tower section of the wind turbine tower and a lower tower stand supporting the lower tower section of the wind turbine tower. The upper tower section further includes an upper power cable connected to the upper tower section. The upper power cable includes a fixed cable section and a movable cable section connected by a cable interface to form the upper power cable. The fixed cable section includes a free end adjacent to the upper tower stand. The upper tower section further includes a lift wire assembly having a fixed end connected to the upper tower section adjacent to its upper end and a free end adjacent to the upper tower stand, and a pulley guide wire having a first end connected to the upper tower section and a free end adjacent to the upper tower stand. The service lift is connected to the upper tower section at a position vertically spaced away from the upper tower stand.

[0022] According to one embodiment of the present invention, the lower tower portion can include a lower power cable having a fixed end adjacent to the lower tower stand and a free end adjacent to the upper end of the lower tower portion. The fixed end of the lower power cable can be connected to or configured to be connected to a power box attached to the lower tower portion.

[0023] According to another embodiment, the upper tower stand can include a temporary power supply.

[0024] In yet another embodiment, the moving cable portion of the upper power cable can include a free end connected to a service lift.

[0025] In one embodiment, the pulley guide wire can include a pulley movably connected thereto, and the moving cable portion can be connected to the service lift so as to engage with the pulley.

[0026] In another embodiment, the upper tower portion can include a plurality of tower sections, and the service lift can be fixed to the upper tower portion at a joint between two adjacent tower sections among the plurality of tower sections.

Brief Description of the Drawings

[0027] The accompanying drawings, which are incorporated herein and constitute a part of this specification, illustrate one or more embodiments of the present invention and, together with the general description of the present invention given above and the detailed description given below, serve to explain the present invention.

[0028] [Figure 1] It is a perspective view of a windmill according to one embodiment of the present invention. [Figure 2] It is a side view of the lower tower portion and the upper tower portion of the tower of the wind turbine of FIG. 1 arranged at the pre-assembly site. [Figure 3] It is a view similar to FIG. 2 and shows a service lift operable within the upper tower portion. [Figure 4]This diagram is similar to Figures 2 and 3, showing a service lift that has been moved to a storage position within the upper tower section and detached for transport of the upper tower section. [Figure 5] This is a side view of the upper and lower tower sections, which are connected to each other at the tower assembly site to form an intermediate assembly tower. [Figure 6] This is a side view of the tower attached to the offshore foundation at the wind turbine site, with the service lift assembled and ready for operation. [Figure 7] This is a side view of the lower and upper tower portions of the wind turbine tower shown in Figure 1, arranged at a pre-assembly site, according to another embodiment of the present invention. [Figure 8] This diagram is similar to Figure 7 and shows a service lift that can operate within the upper tower section. [Figure 9] This diagram is similar to Figures 7 and 8, showing a service lift that has been moved to a storage position within the upper tower section and detached for transport of the upper tower section. [Figure 10] This is a side view of the upper and lower tower sections, which are connected to each other at the tower assembly site to form an intermediate assembly tower. [Figure 11] This diagram is similar to Figure 10, showing the tower assembly site with the upper and lower sections connected to each other, and the service lift installed and operating inside the tower. [Figure 12] This is a side view of a tower attached to an offshore foundation at a wind turbine site, showing the service lift assembled and operational. [Modes for carrying out the invention]

[0029] Referring to Figures 1 to 12, embodiments of a wind turbine tower with a service lift are shown. In particular, the tower is a multipart tower, and a method for installing and operating a service lift within a multipart wind turbine tower is described in detail. In this regard, the wind turbine tower may be pre-assembled into two separate tower sections at one location, such as a pre-assembly site, and then assembled together at another location, such as a tower assembly site. The service lift is used to transport personnel and parts within the tower during the installation, maintenance, and servicing of the wind turbine. In this regard, once the tower is fully assembled, the service lift is configured to traverse the height of the tower, including both tower sections. To simplify the installation of the service lift at the tower assembly site or wind turbine site, the tower sections are pre-assembled or stepped at the pre-assembly site with all the necessary components required to operate the service lift at both the pre-assembly site and the assembly site or wind turbine site. In this way, the service lift can be load-tested, for example, at the pre-assembly site. Furthermore, this reduces the need for large-scale assembly of the service lift at the assembly site or wind turbine site. According to an aspect of the present invention, the service lift is installed in one tower section at the pre-assembly site. Specifically, the service lift is operable inside one of the tower sections, and, for example, one or more operational tests can be performed at the pre-assembly site to verify the proper operation of the service lift. These and other advantages of the present invention are fully described below.

[0030] Referring to Figure 1, a wind turbine 10 is shown, which includes a multipart tower 12 assembled with a service lift 22 (e.g., Figure 6) that can operate inside the tower 12 according to an embodiment of the present invention. The wind turbine 10 further includes a nacelle 14 located at the top of the tower 12, a rotor 16 operably coupled to a generator (not shown) housed inside the nacelle 14, and a gearbox (not shown) also housed inside the nacelle 14. In addition to the generator and gearbox, the nacelle 14 can house various components necessary to convert wind energy into electrical energy and operate the wind turbine 10 to optimize its performance. The tower 12 supports the loads applied by the nacelle 14, the rotor 16, and other wind turbine components housed inside or outside the nacelle 14, and operates to raise the nacelle 14 and rotor 16 to a height above the ground or sea level, where airflow with lower turbulence and higher velocity is typically found.

[0031] The rotor 16 may include a central hub 18 and a plurality of blades 20 mounted on the central hub 18 at positions distributed around the central hub 18. In a typical embodiment, the rotor 16 includes three blades 20, but the number can be varied. The blades 20 projecting radially outward from the central hub 18 are configured to interact with the airflow passing through them to generate a rotational force that rotates the central hub 18 around its longitudinal axis. The design, structure, and operation of the blades 20 are well known to those skilled in the art of wind turbine design and may include additional functional embodiments to optimize performance.

[0032] The rotor 16 can be directly or indirectly coupled to a gearbox by a drive shaft (not shown) to form a rotor assembly. In either case, the gearbox transmits the rotation of the rotor 16 to the generator via a coupling (not shown). Wind exceeding a minimum speed can actuate the rotor 16, causing it to rotate substantially perpendicular to the wind and apply torque to the generator's input shaft. The power generated by the generator can be supplied to a power grid (not shown) or an energy storage system (not shown) for later release to the grid, as will be understood by those skilled in the art. In this way, the kinetic energy of the wind can be utilized by the wind turbine 10 for power generation.

[0033] As briefly described above, aspects of the present invention relate to the assembly and installation of a wind turbine service lift 22 within a wind turbine tower 12. The service lift 22 can be a temporary or permanent fixture within the wind turbine tower 12. As will be described in more detail below, this involves assembling the service lift 22 within a portion or section of the wind turbine tower 12 at a pre-assembly site. The portion of the tower 12 can then be further assembled at another location, for example, the tower assembly site or the wind turbine 10 installation site. In this regard, the tower 12 may be for an offshore wind turbine (to the left of the wind turbine 10 in Figure 1) or an onshore wind turbine (to the right of the wind turbine 10 in Figure 1). Specifically, the tower 12 can be mounted on an offshore foundation 24 or an onshore foundation 26, as shown in the figure. To install the tower 12 on the offshore foundation 24 at the offshore wind turbine site, the tower 12 can be transported to the offshore foundation 24 for installation using an offshore installation vessel 28 or other type of vessel. Although not shown, the offshore installation vessel 28 may feature an onboard crane. The crane can serve a dual purpose: enabling the assembly of the tower 12 on the offshore installation vessel 28 and lowering the assembled tower 12 from the offshore installation vessel 28 onto an offshore foundation 24 on which the tower 12 can be properly mounted. To install the tower 12 onto an onshore foundation 26 at an offshore wind turbine site, the tower 12 can be transported to the onshore foundation 26 for installation using land vehicles. For example, the tower 12 can be lifted onto the foundation 26 using a crane. Embodiments of the tower 12 and the service lift 22 within the tower 12 are shown and described in relation to a tower for use at an offshore wind turbine site, but the methods for installing the tower 12 and the service lift 22 within the tower 12 are not limited to this particular application. For this purpose, the drawings are not intended to be limiting.

[0034] Here, with reference to Figures 2 to 6, a method for assembling a service lift 22 and a wind turbine tower 12 according to a first embodiment of the present invention will be described. As shown in Figure 2, the wind turbine tower 12 includes an upper tower section 30 and a lower tower section 32 located at a pre-assembly site 34. Thus, the tower 12 can be considered a two-part tower. The pre-assembly site 34 includes an upper tower stand 36 configured to receive and support the upper tower section 30, and a lower tower stand 38 configured to receive and support the lower tower section 32, particularly for specific pre-assembly or pre-installation work, as will be described in more detail below. The pre-assembly site 34 defines a storage system 40 for the parts of the wind turbine tower 12. Specifically, the pre-assembly site 34 can function as a storage site where multiple tower sections 30, 32 and other tower components can be staged until they are ready to be assembled elsewhere. The pre-assembly site 34 can be located on the shore, for example, to minimize transportation requirements and facilitate loading of the tower sections 30, 32 onto the service offshore installation vessel 28. Therefore, the tower sections 30 and 32 only need to be transported over short distances and can be quickly loaded onto the offshore installation vessel 28 for shipment to, for example, an offshore wind turbine site.

[0035] Continuing to refer to Figure 2, the upper tower stand 36 is configured to support an upper tower section 30, which includes a first upper tower section 42 and a second upper tower section 44 joined to each other at a joint 46 (interface). The first upper tower section 42 and the second upper tower section 44 are elongated tubular structures that extend longitudinally between opposing open ends where flanges 48 are located. The flanges 48 can be used, for example, to join the tower sections 42, 44 to each other at the joint 46 or to join them to the tower stand 36. As shown, the upper tower section 30 includes two tower sections 42, 44, which may be of similar or different sizes. However, in alternative embodiments, the upper tower section 30 may include fewer or more tower sections 42, 44, such as three. The upper tower section 30 can arrive at the pre-assembly site 34 as an assembly unit that can be mounted or connected to the upper tower stand 36. Alternatively, the upper tower section 30 can be assembled at a pre-assembly site 34 by stacking one of the tower sections 42, 44 on top of the other on an upper tower stand 36. As shown in the figure, each tower section 42, 44 may have one or more intermediate service platforms 50 positioned at different points along its length. The service platforms 50 serve as safe working areas for maintenance workers and can be accessed, for example, via a service lift 22 or ladder (not shown) within the upper tower section 30.

[0036] Continuing to refer to Figure 2, the upper tower section 30 extends between an upper end 52 and a lower end 54, defining an interior 56 that houses, for example, components of a service lift 22. As shown, a first upper tower section 42 can define the upper end 52 of the upper tower section 30, and a second upper tower section 44 can define the lower end 54 of the upper tower section 30. As shown, the lower end 54 is configured to be positioned on the upper tower stand 36 so that the upper tower section 30 is supported by the upper tower stand 36. The lower end 54 of the upper tower section 30 can then be attached to the upper tower stand 36. The upper tower stand 36 can be fixed to the ground or other surface at a pre-assembly site 34 to support the upper tower section 30 on it. The upper tower stand 36 extends from a base 58 to an open end 60 that opens into the interior 62 of the upper tower stand 36. As shown in the figure, the open end 60 of the upper tower stand 36 is dimensioned to accommodate the lower end 54 of the upper tower section 30. For example, the open end 60 of the upper tower stand 36 may include a flange configured to receive a flange 48 at the lower end 54 of the upper tower section 30 for mounting. Once the upper tower section 30 is positioned and fixed on the open end 60 of the upper tower stand 36, the interior 56 of the upper tower section 30 is positioned to communicate with the interior 62 of the upper tower stand 36.

[0037] As shown in Figure 2, the upper tower stand 36 includes a base 64 inside 62 configured to receive the service lift 22 when the service lift 22 is not connected to the upper tower section 30 and requires support. In this regard, the base 64 is configured to support the service lift 22 and may further provide a work area for maintenance personnel to access the service lift 22 for installation and maintenance work and to perform operational tests on the service lift 22. The upper tower stand 36 also includes a temporary power supply 66 configured to supply power to at least the service lift 22, as will be described in more detail below. The temporary power supply 66 may be located on the base 64 as shown, or elsewhere within the upper tower stand 36.

[0038] The service lift 22 can be initially positioned on the base 64 before the upper tower section 30 is attached to the upper tower stand 36 at the pre-assembly site 34. When the service lift 22 is in place on the base 64 within the upper tower stand 36, the upper tower section 30 can be attached to the upper tower stand 36, as shown in Figure 2. This avoids the need for a large crane to lower the service lift 22 through the upper tower section 30 to the base 64, for example. For this purpose, the service lift 22 is accessible from the interior 56 of the upper tower section 30 once the upper tower section 30 is attached to the upper tower stand 36. It should be noted that the size of the service lift 22 is exaggerated to better illustrate aspects of the invention. Therefore, when positioned on the base 64, the service lift 22 can be positioned entirely within the interior 62 of the upper tower stand 36 or partially within the interiors 56, 62 of both the upper tower section 30 and the upper tower stand 36.

[0039] As briefly described above, the service lift 22 is configured to be installed within the upper tower section 30 at the pre-assembly site 34 so that it can be operated. That is, the service lift 22 is operable within the upper tower section 30, and one or more operational tests can be performed at the pre-assembly site 34 to verify the proper operation of the service lift 22. After one or more operational tests have been performed, the service lift 22 may be removed and fixed in place, for example, so that the upper tower section 30 can be transported to the tower assembly site. In this regard, the first upper tower section 42 and the second upper tower section 44 of the upper tower section 30 each contain components necessary to operate the service lift 12 within the upper tower section 30 and within the tower 12 fully assembled elsewhere. Specifically, the upper tower section 30 includes a lift wire assembly 68, an upper power cable 70, and a pulley guide wire 72, as shown in Figure 2. These components form part of a service lift system 74 (for example, Figure 6), which enables the vertical movement (i.e., up and down) of the service lift 22 within the upper tower section 30 at the pre-assembly site 34, as well as vertical movement within the assembled tower 12.

[0040] As will be understood by those skilled in the art, the service lift system 74 includes a service lift 22 that moves vertically (e.g., up and down) along a path of service lift 22 which can extend along the entire length of the tower 12. In particular, the service lift 22 is movable along at least one traction wire of a lift wire assembly 68. The lift wire assembly 68 may further include, for example, one or more safety wires. An upper power cable 70, also called a moving power cable, supplies energy to the service lift 22. The upper power cable 70 may be guided by pulleys as the service lift 22 moves along its path. These and other components of the lift system 74 are described in further detail below where appropriate.

[0041] In another embodiment, the service lift 22 may be guided by rails, ladders, or any other rigid guide elements, rather than by a lift wire assembly 68 (e.g., a tensioned line or cable). The rails or ladders may extend, for example, from the top to the bottom of the wind turbine tower 12.

[0042] Continuing to refer to Figure 2, the first upper tower section 42 includes a lift wire assembly 68 that can be suspended from a support member 76 positioned adjacent to the upper end 52 of the upper tower section 30. The support member 76 may be a crossbeam configured to support the lift wire assembly 68 of the service lift 22, especially when under tension, and to withstand forces associated with the movement of the service lift 22 within the tower 12. As shown, the lift wire assembly 68 includes a first fixed end 78 attached to or fixed to the support member 76 and a second free end 80 suspended within the first upper tower section 42. As will be described in more detail below, the service lift 22 is configured to move vertically along the lift wire assembly 68, and the lift wire assembly 68 keeps the service lift 22 stable and properly positioned during its movement within the assembled tower 12. To accommodate the movement of the service lift 22 within the assembled tower 12, the length of the lift wire assembly 68 may be longer than the length of the first upper tower section 42. The excess length of the lift wire assembly 68 is managed by arranging the free end 80 of the lift wire assembly 68 in a coil shape, as shown in the figure. The coiled free end 80 of the lift wire assembly 68 may be suspended within the first upper tower section 42, for example, or fixed to the first upper tower section 42. In either case, the first upper tower section 42 can be transported to the pre-assembly site with the lift wire assembly 68 already installed and the free end 80 coiled, as shown in the figure. As will be understood by those skilled in the art, the lift wire assembly 68 may comprise several wires and cables, such as a towing wire or cable, a safety wire or cable, and one or more guide wires.

[0043] Continuing to refer to Figure 2, the second upper tower section 44 includes an upper power cable 70 connected to and supported by the flange 48 at the joint 46 between the first tower section 42 and the second tower section 44. The upper power cable 70 is configured to supply power to the movement of the service lift 22 and includes a fixed cable portion 82 and a movable cable portion 84 that are electrically connected at a cable interface 86 to form the upper power cable 70. The cable interface 86 can be located adjacent to the joint 46 between the tower sections 42, 44. As shown, the portion of the power cable 70 that houses the cable interface 86 extends along the length of the flange 48, with the fixed cable portion 82 separated from the movable cable portion 84 by a certain distance around the circumference of the flange 48. The fixed cable portion 82 is attached to the flange 48 and extends to a free end 88 adjacent to the lower end 54 of the upper tower section 30 and the upper tower stand 36. For example, the fixed cable section 82 can be routed within a cable tray along the main access ladder in the tower 12. The movable cable section 84 is suspended from the flange 48 and extends to a free end 90 adjacent to the lower end 54 of the upper tower section 30 and the upper tower stand 36. To accommodate the movement of the service lift 22 within the assembled tower 12, the lengths of the fixed cable section 82 and the movable cable section 84 are at least longer than the length of the second upper tower section 44. The excess length of the cables is managed by coiling the free ends 88, 90 of the fixed cable section 82 and the movable cable section 84, respectively. The coiled free ends 88, 90 of the fixed cable section 82 and the movable cable section 90 can be suspended within the second upper tower section 44 or fixed to the second upper tower section 44, for example. In either case, the second upper tower section 44 can be transported to the pre-assembly site 34 with the upper power cable 70 already installed and the free ends 88 and 90 of the fixed cable section 82 and the movable cable section 84, respectively, coiled as shown in the figure.

[0044] As briefly described above, the second upper tower section 44 includes a pulley guide wire 72 connected to and supported from a flange 48 adjacent to the joint 46. The pulley guide wire 72 is configured to receive a pulley 92 (e.g., Figure 6) used to manage the movement of the mobile power cable section 84. Specifically, the pulley 92 is movably attached to the pulley guide wire 72 to receive the mobile power cable section 84 in order to guide its movement as the service lift 22 moves the lift wire assembly 68. The pulley guide wire 72 includes a fixed end 94 attached to and suspended from one or both of the flanges 48 at the joint 46 between the first upper tower section 42 and the second upper tower section 44. For example, the fixed end 94 may be connected to the upper flange 48 of the second upper tower section 44. The pulley guide wire 72 extends from the fixed end 94 to a free end 96 adjacent to the lower end 54 of the upper tower section 30 and the upper tower stand 36. To accommodate the movement of the service lift 22 within the assembled tower 12, the length of the pulley guide wire 72 is at least longer than the length of the second upper tower section 44. The excess length of the cable is managed by coiling the free end 96 of the pulley guide wire 72, as shown. The coiled free end 96 of the pulley guide wire 72 may be suspended within the second upper tower section 44, for example, or it may be fixed to the second upper tower section 44. In either case, the second upper tower section 44 may be transported to the pre-assembly site with the pulley guide wire 72 already installed and the free end 96 coiled, as shown.

[0045] Referring again to Figure 2, the details of the lower tower section 32 will now be described. As shown in the figure, the lower tower section 32 extends between the upper end 100 and the lower end 102, defining an interior 104 that houses, for example, components of a service lift 22. As shown in the figure, the lower end 104 is positioned on the lower tower stand 38, so that the lower tower section 32 is supported by the lower tower stand 38. The lower end 104 of the lower tower section 32 can then be attached to the lower tower stand 38. The lower tower section 32 further includes a first lower tower section 106 and a second lower tower section 108 that are attached to each other at a joint 110. The first lower tower section 106 and the second lower tower section 108 are elongated tubular structures that extend longitudinally between open ends on which flanges 112 are located. The flanges 112 can be used, for example, to connect the tower sections 106 and 108 to each other at the joint 110, or to connect to the lower tower stand 38. As shown in the figure, the lower tower section 32 includes two tower sections 106, 108 which may be of similar or different sizes. In another embodiment, the lower tower section 32 may include fewer or more tower sections 106, 108, such as three. The lower tower section 32 can arrive at the pre-assembly site 34 as an assembled unit mounted on the lower tower stand 38. Alternatively, the lower tower section 32 can be assembled at the pre-assembly site 34, for example, by stacking the tower sections 106, 109 on top of each other on the lower tower stand 38. Each tower section 106, 108 may have one or more intermediate service platforms 50 installed at different points along its length, as required by the tower design.

[0046] As shown in the figure, the first lower tower section 106 can define the upper end 100 of the lower tower portion 32, and the second lower tower section 108 can define the lower end 102 of the upper tower portion 32. The lower end 102 of the lower tower portion 32 is configured to be attached to the lower tower stand 38, for example, via a flange 112. In this regard, the lower tower stand 38 can be fixed to the ground or other surface at the pre-assembly site 34 to support the lower tower portion 32 on it. Specifically, the lower tower stand 38 extends from the base 114 to an open end 116 that opens to the interior 118 of the lower tower stand 38. As shown in the figure, the open end 116 of the lower tower stand 38 is dimensioned to correspond to receiving the lower end 102 of the lower tower portion 32. For example, the open end 116 of the lower tower stand 38 may include a flange configured to receive the flange 112 at the lower end 102 of the lower tower portion 32 for attachment. Once the lower tower section 32 is fixed to the open end 116 of the lower tower stand 38, the interior 104 of the lower tower section 32 is arranged to communicate with the interior 118 of the lower tower stand 38. For this purpose, the interior 104 of the lower tower section 32 can be accessed from the interior 118 of the lower tower stand 38 to access certain components of the service lift 22, as will be described in more detail below.

[0047] Continuing to refer to Figure 2, the lower tower section 32 includes certain other components of the service lift 22 necessary to operate the service lift 22 within the tower 12 after the tower 12 has been assembled. In this regard, the lower tower section 32 includes a lower power cable 120 connected to a power box 122. Once the tower 12 is fully assembled, the lower power cable 120 is configured to connect to the upper power cable 70 of the upper tower section 30 to supply power to the service lift 22. The power box 122 is mounted on the second lower tower section 108 adjacent to the lower end 102 of the lower tower section 32. The lower power cable 120 includes a fixed end 124 configured to be electrically connected to the power box 122. The lower power cable 120 extends from the fixed end 124 to a free end 126 located adjacent to the upper end 100 of the lower tower section 32. For example, the lower power cable 120 may be located in a cable tray that extends along the tower wall of the lower tower section 32. The length of the lower power cable 120 may need to be longer than the length of the lower tower section 32, for example, to reach the upper tower section 30 for connection to the upper power cable 70. The excess length of the lower power cable 120 is managed by arranging the free end 126 of the lower power cable 120 in a coiled shape. The coiled free end 126 of the lower power cable 120 can be fixed to the lower tower section 32, for example, to a flange 112 at the upper end 100 of the lower tower section 32. The lower tower section 32 can be transported to the pre-assembly site 34 with the lower power cable 120 already installed and the free end 126 coiled, as shown in the figure. The fixed end 124 of the lower power cable 120 may be connected to a power box 122 at the pre-assembly site 34, for example.

[0048] Having described the specific details of the upper tower section 30 and the lower tower section 32 up to this point, the method of assembling the tower 12, including the installation and testing of the service lift 22, will now be described according to one embodiment of the present invention with reference to Figures 1 to 6. In this regard, the upper tower section 30 and the lower tower section 32 are received at the pre-assembly site 34 as described above. Specifically, the upper tower section 30 and the lower tower section 32 are placed on the upper tower stand 36 and the lower tower stand 38, respectively, as shown in Figure 2. With respect to the lower tower section 32, the fixed end 124 of the lower power cable 120 can be connected to the power box 122 if it has not yet been connected. Similarly, the free end 126 of the lower power cable 120 can be placed at the upper end 100 of the lower tower section 32, where it can be coiled and secured. At this point, the lower tower section 32 is pre-assembled and ready to be transported from the pre-assembly site 34 to another location.

[0049] With respect to the upper tower section 30, and particularly the service lift 22, as shown in Figure 2, once the upper tower section 30 is secured to the upper tower stand 36 so as to support it, the service lift 22 can be temporarily assembled to be operable within the upper tower section 30, and one or more operational tests can be performed to verify the proper operation of the service lift 22. In this regard, the free end 80 of the lift wire assembly 68 can be connected to the base 64 of the upper tower stand 36, rather than being coiled, as shown in Figure 3. Furthermore, the service lift 22 can be operably connected to a lift wire assembly 68, which may include traction wires or cables, safety wires or cables, and one or more guide wires, so as to be movable along the lift wire assembly 68. In this regard, the service lift 22 may include a motor configured to drive the movement of the service lift 22 along the lift wire assembly 68. For this purpose, once the lift wire assembly 68 is connected to the service lift 22 and the base 64, the lift wire assembly 68, in particular the traction wire, guide wire, and safety wire, can be appropriately tensioned so that the service lift 22 can be commissioned and load tested, for example, within the upper tower section 30.

[0050] Continuing to refer to Figure 3, the temporary power cable 128 is connected between the temporary power supply 66 and the service lift 22, supplying power to the vertical movement of the service lift 22 along the lift wire assembly 68. Once the lift wire assembly 68 and the temporary power cable 128 are in place, the service lift 22 may be considered operational for, for example, one or more operational tests. After the testing and commissioning work is complete, the service lift 22 can be further operated to move it upward from the base 64 and upper tower stand 36 to the joint 46 between the first upper tower section 42 and the second upper tower section 44, where the service lift 22 can be fixed in place relative to the upper tower section 30. In this regard, Figure 4 shows the service lift 22 in a stowed position where it is fixed to the upper tower section 30 near the joint 46. When in the stowed position, the service lift 22 is positioned vertically away from the upper tower stand 36. In the illustrated embodiment, the service lift 22 is secured to the upper tower section 30 by one or more connectors 130.

[0051] In one embodiment, the service lift 22 is secured to one of the tower flanges 48 at joint 46 using one or more connectors 130 in the form of magnetic brackets that can be attached to one of the tower flanges 48. In another embodiment, the service lift 22 is secured to one of the tower flanges 48 at joint 46 using one or more connectors 130 in the form of bolts. However, other fastening means are possible for securing the service lift 22 to the upper tower section 30 in the stowed position, such as clips, screw clamps, clamp brackets, screw-in brackets, tension brackets, or other suitable fastening hardware.

[0052] Continuing to refer to Figure 4, once the service lift 22 is moved to its storage position and secured to the upper tower section 30 at the joint 46, the components of the service lift 22 can be detached so that the upper tower section 30 can be transported, for example, to a tower assembly site. In this regard, the tension of the lift wire assembly 68 is released, and the free end 80 of the lift wire assembly 68 is detached from the base 64 of the upper tower stand 36. The lift wire assembly 68 may remain connected to the service lift 22, or the free end 80 of the lift wire assembly 68 may be coiled and placed for storage. For this purpose, the coiled free end 80 of the lift wire assembly 68 can be placed or stored adjacent to the lower end 54 of the upper tower section 30. In addition, the temporary power cable 128 is detached from the service lift 22 and stored so as not to obstruct the removal of the upper tower section 30 from the upper tower stand 36.

[0053] Figure 4 shows the upper tower section 30 and the lower tower section 32, which have been pre-assembled and are ready to be moved to a tower assembly site where the upper tower section 30 and the lower tower section 32 can be further assembled. In this regard, the upper tower section 30 and the lower tower section 32 can be detached and removed from the upper tower stand 36 and the lower tower stand 38, respectively, using, for example, a crane. The upper tower section 30 and the lower tower section 32 can be transported to the tower assembly site 132 using, for example, a crane, a large truck, a train, or a ship. As shown in Figure 5, at the tower assembly site 132, the upper tower section 30 is positioned vertically on top of the lower tower section 32 to form the intermediate assembled wind turbine tower 12a. The tower assembly site 132 can be on land, such as on a shore on an offshore installation vessel 28 that transports the tower 12a to the offshore foundation 24, or offshore, such as on the offshore foundation 24. In either case, the lower end 54 of the upper tower section 30 is attached to the upper end 100 of the lower tower section 32 at the tower section joint 134 at the tower assembly site 132, as shown in Figure 5, to form the intermediate assembled tower 12a. The upper end 52 of the upper tower section 30 can form the top of the towers 12, 12a, and the lower end 54 of the lower tower section 32 can form the base of the towers 12, 12a, including the entrance platform 136. The lower end 54 of the lower tower section 32 may also include an access door 137, as shown. The tower 12a is considered partially assembled because, while the intermediate assembled tower 12a is at the tower assembly site 132, components of the service lift 22, such as the lift wire assembly 68, power cables 70, 120, and pulley guide wire 72, remain detached. In another embodiment, some or all of the components of the service lift 22 can be assembled at the tower assembly site 132. For example, the free end 126 of the lower power cable 120 may be connected to the free end 88 of the fixed cable portion 82 of the upper power cable 70.

[0054] In embodiments not shown, the foundation 24 includes an extension transition piece, which is known to those skilled in the art. The extension transition piece is a tubular structure similar to a smaller tower section that is attached to the foundation 24 and extends above the foundation 24. The extension transition piece joins the lower end 54 of the lower tower section 32 at its upper end. In this embodiment, the access door 137 is located within the extension transition piece. The lower end 54 of the lower tower section 32 does not have an access door 137.

[0055] Referring here to Figures 5 and 6, the intermediate assembly tower 12a is then transported from the tower assembly site 132 to the wind turbine site 138. In the illustrated embodiment, the tower assembly site 132 is located on the offshore installation vessel 28. In this regard, the offshore installation vessel 28 moves the intermediate assembly tower 12a to the wind turbine site 138 where it will be placed on the offshore foundation 24. As described above, the offshore installation vessel 28 may also be characterized by being equipped with a crane used to lower the intermediate assembly tower 12a from the offshore installation vessel 28 onto the offshore foundation 24, so that the intermediate assembly tower 12a can be properly attached to the offshore foundation 24. In particular, the base of the tower 12a is attached to the offshore foundation 24 to secure the tower 12a so that the tower 12a is supported on the offshore foundation 24, as shown in Figure 6. Once positioned in this manner, the service lift 22 can be assembled within the tower 12a, as will be described in more detail below.

[0056] Continuing to refer to Figure 5, the service lift 22 is assembled within the tower 12a by connecting the free end 80 of the lift wire assembly 68 and the free end 96 of the pulley guide wire 72 to the offshore foundation 24 or inlet platform 136 at the base of the tower 12a. The lift wire assembly 68 and the pulley guide wire 72 can then be properly tensioned. If not already connected, the fixed end 124 of the lower power cable 120 can be connected to the power box 122 in the lower tower section 32 of the wind turbine tower 12a. The free end 126 of the lower power cable 120 may be connected to the free end 88 of the fixed cable section 82 of the upper power cable 70 at the cable interface 140. Once connected, the upper power cable 82 and the lower power cable 120 are configured to supply power to the service lift 22. In this regard, the free end 90 of the movable cable section 84 of the upper power cable 70 may be fed through the pulley 92 of the pulley guide wire 72 and connected to the service lift 22, as shown in the figure. When the service lift 22 is electrically connected to the power box 122 via the upper power cable 70 and the lower power cable 120, the service lift 22 becomes operational.

[0057] Before operating the service lift 22, it is first necessary to release the service lift 22 from the upper tower section 30. This is done by disconnecting or deactivating one or more connectors 130 that allow the service lift 22 to move from its housing position. Once released, the service lift 22 may be operated to traverse the height of the lift wire assembly 68 and thus the height of the tower 12. The height of the tower 12 can be defined by the distance between the upper end 52 of the upper tower section 30 (i.e., the top of the tower 12) and the lower end 54 of the lower tower section 32 (i.e., the base of the tower 12). As shown in the figure, the lift wire assembly 68 extends substantially the entire height of the tower 12. In this way, the service lift 22 is movable along the lift wire assembly 68 over substantially the entire height of the tower 12. For this purpose, the tower 12 shown in Figure 6 can be considered fully assembled to receive other components of the wind turbine 10, such as the nacelle 14.

[0058] A pulley 92 is used to ensure the smooth and organized movement of the moving cable portion 84 of the upper power cable 70 as the service lift 22 moves along the lift wire assembly 68. In this regard, the pulley 92 is configured to receive the moving cable portion 84 and move along the pulley guide wire 72 as the service lift 22 moves. Specifically, as the service lift 22 moves up and down along the lift wire assembly 68, the pulley 92 moves along the pulley guide wire 72 accordingly. For this purpose, the slack in the moving cable portion 84 of the power cable 70 can increase when the service lift 22 is closer to the top 52 of the tower 12 compared to when the service lift 22 is closer to the base 136 of the tower 12. As shown in Figure 6, the pulley guide wire 72 is positioned close to the side walls of the upper tower portion 30 and the lower tower portion 32, rather than at the axial center of the tower 12. Furthermore, by passing the movable cable portion 84 through a movable pulley 92 attached to the pulley guide wire 72, the movable cable portion 84 of the upper power cable 70 is also moved away from the axis of the tower 12. This prevents the movable cable portion 84 from colliding with other wind turbine components that can be positioned or moved through the axial center of the tower 12.

[0059] Here, with reference to Figures 7 to 12, a method for assembling the tower 12, including the installation and testing of the service lift 22, will be described according to another embodiment of the present invention. In this regard, similar reference numerals represent similar features compared to the embodiments described above with reference to Figures 1 to 6. The main difference between the method of this embodiment and the method of the previously described embodiments is that the upper power cable 70, in particular the movable cable portion 84 of the upper power cable 70, is connected to the service lift 22 to supply power to the service lift 22 at the pre-assembly site 34. Thus, the upper power cable 70 is used to supply power to the service lift 22 at the pre-assembly site 34, for example, instead of using the temporary power cable 128 described above.

[0060] Referring to Figure 7, the upper tower section 30 and the lower tower section 32 are received at the pre-assembly site 34 as described above. Specifically, the upper tower section 30 and the lower tower section 32 are placed on the upper tower stand 36 and the lower tower stand 38, respectively, as shown in the figure. With respect to the lower tower section 32, the fixed end 124 of the lower power cable 120 can be connected to the power box 122 if it has not yet been connected. Similarly, the free end 126 of the lower power cable 120 can be placed on the upper end 100 of the lower tower section 32, where it can be coiled and fixed. At this point, the lower tower section 32 is pre-assembled and ready to be transported from the pre-assembly site 34 to the tower assembly site 132.

[0061] Once the upper tower section 30 is fixed to the upper tower stand 36, the service lift 22 is temporarily assembled to be operable within the upper tower section 30, and one or more operational tests can be performed to verify the proper operation of the service lift 22. In this regard, for example, the free end 80 of a lift wire assembly 68, which may include at least a traction wire or cable, a safety wire or cable, and one or more guide wires, can be unwound and connected to the base 64 of the upper tower stand 36, as shown in Figure 8. Furthermore, the service lift 22 is operablely connected to the lift wire assembly 68, such as a traction wire, so that it can move along the lift wire assembly 68 as described above. The free end 96 of the pulley guide wire 72 is also unwound and connected to the base 64 of the upper tower stand 36. The lift wire assembly 68 and the pulley guide wire 72 can be appropriately tensioned so that one or more operational tests can be performed, for example, to operate the service lift 22.

[0062] Continuing to refer to Figure 8, the upper power cable 70 is connected to the temporary power supply 66 and the service lift 22 to supply power to move the service lift 22 vertically along the lift wire assembly 68 within the upper tower section 30. In this regard, the free end 90 of the moving cable section 84 is unwound and fed through the pulley 92 of the pulley guide wire 72 and connected to the service lift 22. To accommodate the movement of the service lift 22 within the assembled tower 12, the length of the moving cable section 84 can be longer than the length required to move the service lift 22 within the upper tower section 30. The excess length of the moving cable section 84 can be managed by arranging sections or lengths of the moving cable section 84 in the coil 142, as shown in the figure. Once the lift wire assembly 68, the upper power cable 70, and the pulley guide wire 72 are installed, the service lift 22 may be considered operational for performing one or more operational tests, for example, at the pre-assembly site 34.

[0063] Referring to Figures 8 and 9, once the testing and commissioning work is complete, the service lift 22 is further operated to move it upward from the base 64 and upper tower stand 36 to the joint 46 between the first tower section 42 and the second upper tower section 44, where the service lift 22 can be secured to the upper tower section 30. Specifically, the service lift 22 is secured to the upper tower section 30 at a position vertically separated from the upper tower stand 36. In this regard, Figure 9 shows the service lift 22 moved to a stowed position where it is secured to the upper tower section 30 at the joint 46. Similar to the embodiments described above, the service lift 22 is secured to the upper tower section 30 by one or more connectors 130. Once the service lift 22 is moved to a stowed position where it is secured to the upper tower section 30, the components of the service lift 22 can be detached so that the upper tower section 30 can be transported to the tower assembly site 132, for example, as will be described in more detail below.

[0064] Figure 9 shows the detached service lift 22, meaning the upper tower section 30 can be moved to the tower assembly site 132. Specifically, the tension on the lift wire assembly 68 is released, and the free end 80 of the lift wire assembly 68 is detached from the base 64 of the upper tower stand 36 and arranged in a coil. Similarly, the tension on the pulley guide wire 72 is released, and the free end 96 of the pulley guide wire 72 is detached from the base 64 of the upper tower stand 36 and arranged in a coil. The free end 88 of the fixed cable section 72 of the upper power cable 70 is detached from the temporary power supply 66 and arranged in a coil. It is important to note that the free end 90 of the movable cable section 84 of the upper power cable 70 remains connected to the service lift 22, and the movable cable section 84 remains connected to the pulley 92 of the pulley guide wire 72. This eliminates the need to establish these connections at, for example, the tower assembly site 132, resulting in time and cost savings during installation.

[0065] Figure 9 shows the upper tower section 30 and lower tower section 32, which have been pre-assembled and are ready to be moved to a tower assembly site 132 where the upper tower section 30 and lower tower section 32 can be assembled to form the wind turbine tower 12. In this regard, Figure 10 shows the upper tower section 30, which is positioned vertically on the lower tower section 32 at the tower assembly site 132 to form the intermediate assembled wind turbine tower 12b. Similar to the embodiments described above, the tower 12b is considered intermediate assembled because, while the intermediate assembled tower 12b is at the tower assembly site 132, components of the service lift 22, such as the lift wire assembly 68, power cables 70, 120, and pulley guide wire 72, remain disconnected or are only partially connected. In the illustrated embodiment, the tower assembly site 132 is on an offshore installation vessel 28, but the tower assembly site 132 may be, for example, a shore.

[0066] Referring to Figures 10 and 11, the service lift 22 can be assembled within the tower 12b at the tower assembly site 132. In this regard, the free end 80 of the lift wire assembly 68 and the free end 96 of the pulley guide wire 72 are connected to the entrance platform 136 at the base of the tower 12b. The lift wire assembly 68 and the pulley guide wire 72 can then be properly tensioned. If not already connected, the fixed end 124 of the lower power cable 120 can be connected to the power box 122 in the lower tower section 32 of the wind turbine tower 12b. The free end 126 of the lower power cable 120 may be connected to the free end 88 of the fixed cable section 82 of the upper power cable 70 at the cable interface 140. Once connected, the upper power cable 70 and the lower power cable 120 are configured to supply power to the service lift 22. At this point, the service lift 22 can be released from the upper tower section 30 and moved to a resting position near the base 136 of the tower, as shown in Figure 11. This is done by disconnecting or stopping one or more connectors 130 so that the service lift 22 can be moved from its hoisted position. Once released, the service lift 22 becomes fully operational and can move downward along the lift wire assembly 68 toward the base 136 of the assembled tower 12. In another embodiment, the service lift 22 can remain in a hoisted position fixed to the upper tower section 30 until the tower 12 is installed on the offshore foundation 24 at the wind turbine site 138.

[0067] Referring here to Figure 12, the assembled tower 12 is then transported to the wind turbine site 138 for installation. In this regard, the offshore installation vessel 28 transports the tower 12 to the wind turbine site 138 where the offshore foundation 24 is to be laid. As described above, the offshore installation vessel 28 may be characterized by being equipped with a crane used to lower the tower 12 from the offshore installation vessel 28 onto the offshore foundation 24, so that the tower 12 can be properly attached to the offshore foundation 24. In particular, the base of the tower 12 is connected to or attached to the offshore foundation 24 to secure the tower 12 to the offshore foundation 24, so that the tower 12 is supported on the offshore foundation 24 as shown in the figure, and the service lift 22 is operable within the tower 12.

[0068] While the present invention has been illustrated by descriptions of various preferred embodiments, and these embodiments have been described in some detail, it is not the applicant's intention to limit the scope of the appended claims in such detail or in any way. Additional advantages and modifications will be readily apparent to those skilled in the art. Thus, the various features of the present invention may be used individually or in any combination, depending on the user's needs and preferences.

Claims

1. A method for installing a service lift (22) inside a wind turbine tower (12), wherein the wind turbine tower (12) is The method includes an upper tower portion (30) and a lower tower portion (32), wherein the upper tower portion (30) is connected to the lower tower portion (32) to form the wind turbine tower (12), and the method is as follows: The upper tower stand (36) will be installed at the tower pre-assembly site (34), The service lift (22) is provided on the upper tower stand (36), Position the upper tower portion (30) of the wind turbine tower (12) on the upper tower stand (36) so that the upper tower portion (30) is supported on the upper tower stand (36), The service lift (22) in the upper tower stand (36) is connected to the upper tower portion (30) of the wind turbine tower (12) so that it can operate within the upper tower portion (30). To operate the service lift (22) within the upper tower portion (30) of the wind turbine tower (12), A method comprising fixing the service lift (22) to the upper tower portion (30) at a position vertically separated from the upper tower stand (36) for the subsequent assembly of the wind turbine tower (12).

2. The upper tower portion (30) includes a lift wire assembly (68) having a first fixed end (78) and a second free end (80) attached to the upper tower portion (30) adjacent to its upper end (52), The method according to claim 1, wherein operably connecting the service lift (22) within the upper tower portion (30) includes connecting the free end (80) of the lift wire assembly (68) to the upper tower stand (36) and connecting the lift wire assembly (68) to the service lift (22) so that the service lift (22) is movable along the lift wire assembly (68).

3. The upper tower stand (36) further includes a temporary power supply (66), and the method is The method according to claim 1 or 2, further comprising connecting the service lift (22) to the temporary power supply (66) in the upper tower stand (36) so that the service lift (22) can operate within the upper tower portion (30).

4. The method according to claim 3, further comprising connecting the service lift (22) to the temporary power supply (66) to provide a temporary power cable (128), and connecting the temporary power cable (128) between the temporary power supply (66) and the service lift (22).

5. The upper tower portion (30) of the wind turbine tower (12) includes an upper power cable (70) connected to the upper tower portion (30), and the upper power cable (70) includes a fixed cable portion (82) and a movable cable portion (84) connected by a cable interface (86) to form the upper power cable (70). The fixed cable portion (82) includes a free end (88) adjacent to the lower end (54) of the upper tower portion (30), The movable cable portion (84) includes an upper power cable (70) which includes a free end (90) adjacent to the lower end (54) of the upper tower portion (54). The method according to claim 3, further comprising connecting the free end (88) of the fixed cable portion (82) to the temporary power supply (66) and connecting the free end (90) of the movable cable portion (84) to the service lift (22).

6. The upper tower portion (30) has a pulley guide wire (72) having a fixed end (94) connected to the upper tower portion (30) and a free end (96) connected to the upper tower stand (36), The system further comprises a pulley (92) movably attached to the pulley guide wire (72), The method according to claim 5, wherein connecting the free end (90) of the movable cable portion (84) to the service lift (22) further includes connecting the free end (90) of the movable cable portion (84) to the service lift (22) such that the pulley (92) engages with the pulley guide wire (72).

7. The method according to any one of claims 1 to 6, wherein, after fixing the service lift (22) to the upper tower portion (30), the method further comprises detaching the service lift (22) within the upper tower portion (30) from the upper tower stand (36) so that the service lift (22) becomes inoperable within the upper tower portion (30).

8. The method according to claim 7, as dependent on claim 2, wherein detaching the service lift (22) from the upper tower stand (36) includes detaching the free end (80) of the lift wire assembly (68) from the upper tower stand (36).

9. The method according to claim 7 or 8, as dependent on claim 3, wherein disconnecting the service lift (22) from the upper tower stand (36) includes disconnecting the service lift (22) from the temporary power supply (66).

10. The method according to claim 9, as dependent on claim 5, wherein disconnecting the service lift (22) from the upper tower stand (36) includes disconnecting the free end (88) of the fixed cable portion (82) of the upper power cable (70) from the temporary power supply (66).

11. The method according to any one of claims 7 to 10, as dependent on claim 6, wherein disconnecting the service lift (22) from the upper tower stand (36) includes disconnecting the free end (96) of the pulley guide wire (72) from the upper tower stand (36).

12. The method according to any one of claims 1 to 11, wherein operating the service lift (22) within the upper tower portion (30) of the wind turbine tower (12) includes performing one or more operational tests to verify the proper operation of the service lift (12).

13. The aforementioned upper tower portion (30) includes a plurality of tower sections, The method according to any one of claims 1 to 12, wherein fixing the service lift (22) to the upper tower portion (30) includes fixing the service lift (22) to the upper tower portion (30) at a joint (46) between two adjacent tower sections (42, 44) of the plurality of tower sections.

14. The lower tower stand is to be installed at the aforementioned tower pre-assembly site (34), The lower tower portion (32) of the wind turbine tower (12) is positioned on the lower tower stand (38) such that the lower tower portion (32) is supported on the lower tower stand (38), The method according to any one of claims 1 to 13, wherein the lower tower portion (32) includes a lower power cable (120) having a fixed end (124) adjacent to the lower end (102) of the lower tower portion (32) for connecting to a power box (122) attached to the lower tower portion (32), and a free end (126) adjacent to the upper end (100) of the lower tower portion (32) for connecting to the upper power cable (120).

15. The method according to any one of claims 1 to 14, wherein the tower pre-assembly site (34) is on land, preferably on the shore.

16. A method for assembling a wind turbine tower (12), At the tower pre-assembly site (34), a service lift (22) is installed on the wind turbine tower (12) according to claim 14 or 15. Moving the lower tower section (32) from the tower pre-assembly site (34) to the tower assembly site (132), Moving the upper tower section (30) from the tower pre-assembly site (34) to the tower assembly site (132), A method comprising connecting the upper tower portion (30) to the lower tower portion (32) to form the wind turbine tower (12).

17. The method according to claim 16, wherein the tower assembly site (132) is mounted on an offshore installation vessel (28).

18. A method for installing a wind turbine tower (12) at an offshore wind turbine installation site (138), Assembling the wind turbine tower (12) according to claim 16 or 17, The wind turbine tower (12) is connected to the offshore foundation (24), The first fixed end (124) of the lower power cable (120) is connected to the power box (122) of the lower tower portion (32) of the wind turbine tower (12), The second free end (126) of the lower power cable (120) is connected to the free end (88) of the fixed cable portion (82) of the upper power cable (70), The free end (80) of the lift wire assembly (68) is connected to the entrance platform (136) of the wind turbine tower (12), A method comprising connecting the free end (96) of the pulley guide wire (72) to the inlet platform (136) of the wind turbine tower (12), and optionally connecting the free end (90) of the movable cable portion (84) to the service lift (22).

19. The method according to claim 18, further comprising releasing the service lift (22) from the upper tower portion (30) of the wind turbine tower (12) so that it can be operated within the wind turbine tower (12).

20. A storage system (40) for a wind turbine tower (12) having a service lift (22), The wind turbine tower (12) includes an upper tower portion (30) and a lower tower portion (32), and the storage system (40) is The wind turbine tower (12) includes an upper tower stand (36) that supports the upper tower portion (30) and a lower tower stand (38) that supports the lower tower portion (32), The aforementioned upper tower portion (30) is The upper power cable (70) connected to the upper tower section (30), A lift wire assembly (68) having a fixed end (78) connected to the upper tower portion (30) adjacent to its upper end (52), and a free end (80) adjacent to the upper tower stand (36), The pulley guide wire (72) includes a first end (94) connected to the upper tower portion (30) and a free end (96) adjacent to the upper tower stand (36), The service lift (22) is a storage system (40) that includes a pulley guide wire (72) connected to the upper tower portion (30) at a position vertically separated from the upper tower stand (36), The upper power cable (70) includes a fixed cable portion (82) and a movable cable portion (84) connected by a cable interface (86) to form the upper power cable (86), the fixed cable portion (82) having a free end (88) adjacent to the upper tower stand (36), the storage system (40).

21. The lower tower portion (32) is provided with a lower power cable (120) having a fixed end (124) adjacent to the lower tower stand (38) and a free end (126) adjacent to the upper end (100) of the lower tower portion (32). The storage system (40) according to claim 20, wherein the fixed end (124) of the lower power cable (120) is connected to or configured to be connected to a power box (122) attached to the lower tower portion (32).

22. The storage system (40) according to claim 20 or 21, wherein the upper tower stand (36) includes a temporary power supply (66).

23. The storage system (40) according to any one of claims 20 to 22, wherein the movable cable portion (84) of the upper power cable (70) includes a free end (90) connected to the service lift (22).

24. The pulley guide wire (72) includes a pulley (92) movably connected thereto. The storage system (40) according to claim 23, wherein the movable cable portion (84) is connected to the service lift (22) so as to engage with the pulley (92).

25. The aforementioned upper tower portion (30) includes a plurality of tower sections, The storage system (40) according to any one of claims 20 to 24, wherein the service lift (22) is fixed to the upper tower portion (30) at a joint (46) between two adjacent tower sections (42, 44) of the plurality of tower sections.

Images