Cable guiding in wind turbine towers

Abstract

To provide cable arrangements and methods for guiding cables in large wind turbines with relatively high power ratings.SOLUTION: The present disclosure relates to towers for wind turbines, the towers comprising a top section supporting a nacelle of the wind turbines about a yaw axis, where the nacelle comprises an electric power component and a power cable for electrically connecting the electric power component to an electrical connection point in a lower section of the tower. The power cable extends downwards from the nacelle to a first height along a substantially central area of the tower, and at the first height, the power cable comprises a power cable loop. The power cable loop includes an upward curve, and a downward curve. The power cable loop comprises a movable cable part and a fixed cable part, and the fixed cable part comprises at least a portion of the downward curve. The present disclosure further relates to wind turbines and to methods for arranging cables in the wind turbine towers.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to wind turbines, and more particularly to a system for guiding a power cable down a wind turbine tower. The present disclosure further relates to a wind turbine tower. [Background technology]

[0002] Modern wind turbines are commonly used to supply electricity to the power grid. This type of wind turbine generally comprises a tower and a rotor disposed on the tower. The rotor, which typically comprises a hub and a number of blades, rotates under the influence of wind on the blades. The rotation typically generates torque that is transmitted via the rotor shaft to a generator, either directly or via a gearbox. In this way, the generator produces electricity that can be supplied to the power grid.

[0003] The wind turbine hub may be rotatably coupled to the front of the nacelle. The wind turbine hub may be connected to a rotor shaft, which may then be rotatably mounted within the nacelle using one or more rotor shaft bearings located within a frame inside the nacelle. The nacelle is a housing located at the top of the wind turbine tower that houses and protects, for example, the gearbox (if present) and generator, and, depending on the wind turbine, further components such as power converters and auxiliary systems.

[0004]

[0003] Power cables carry electrical energy from the generator in the nacelle, down the wind turbine tower, and to the power grid. Power cables typically include bundles of metal wires, e.g., copper wires, surrounded by a protective and flexible covering, e.g., a rubber covering. Power cables in wind turbines are expected to withstand vibration, bending, twisting, abrasion, a wide range of temperatures, and electromagnetic interference. In offshore wind turbines, they must also be resistant to salt water and tidal air.

[0005] The power cable must allow the nacelle to yaw while still reliably transporting electrical energy. When the wind direction changes, the nacelle turns to match the wind direction. The nacelle may make three or more complete revolutions before rewinding in the opposite direction. The power cable must be able to withstand the corresponding twist. Twisting also leads to shortening of the power cable. The power cable must also have an additional extra length to be able to compensate. This additional length is usually provided through a cable saddle, i.e., a portion of the cable is guided beyond the curved structure. The curved structure may be formed as a semi-cylinder. The power cable may be guided beyond the upper surface of the semi-cylinder. The radius of the semi-cylinder may be determined depending on the cable used. The minimum bending radius of the cable must be respected.

[0006] The minimum bend radius of a cable may depend, among other things, on the power and voltage ratings of the cable. The amount of electrical insulation and the diameter of the wire bundle within the cable may depend, among other things, on the voltage rating. Similarly, the twisting ability of a cable may depend on the cable configuration.

[0007] It is an object of the present disclosure to provide a cable arrangement and method for guiding cables in large wind turbines having relatively high power ratings. It is a further object of the present disclosure to provide a method and system for guiding medium or high voltage power cables within a wind turbine. Summary of the Invention

[0008] In one aspect of the disclosure, a tower for a wind turbine is provided. The tower includes a top portion supporting a nacelle of the wind turbine about a yaw axis, the nacelle including power components and a power cable for electrically connecting the power components to an electrical connection point at a bottom of the tower. The power cable extends downward from the nacelle along a substantially central region of the tower, and at a first height, the power cable includes a power cable loop. The power cable loop includes an upward curve and a downward curve. The power cable loop includes a movable cable portion and a fixed cable portion, the fixed cable portion including at least a portion of the downward curve.

[0009] A loop, as used throughout this disclosure, can be understood as a segment of cable that includes a subsequent portion that extends longitudinally in the opposite direction. In other words, a loop is formed by a cable that extends in a first direction and includes a portion that extends substantially in the opposite direction and a portion that continues back in the first direction. In particular, in this disclosure, a loop includes a downward portion (from the nacelle down to the tower), a subsequent upward portion, and a further subsequent downward portion (or, considered in the opposite direction, an upward portion, a subsequent downward portion, and a further upward portion). A cable loop can provide slack to accommodate nacelle movement. The subsequent cable portion where the cable changes direction may be curved. The upward portion may form an upward curve, and the downward portions before and after the upward portion may both form downward curves.

[0010] These subsequent cable portions may form a full 360° curve. The cable portions may form substantially circular segments, but need not form a complete circle, and the segments need not be circular.

[0011] According to this aspect, a tower for a wind turbine includes a power cable arrangement that can accommodate cables with an increased minimum bend radius. Because the cable loop is partially movable and partially fixed, with a portion of the cable loop formed by a fixed cable section, the movable section is configured to provide slack and can accommodate movement without having to make a complete loop from downward, upward, and again downward. Thus, the radius of the power cable loop can be increased. Thus, a cable arrangement with sufficient power and voltage rating (and associated torsion capacity) can be provided within a section of the tower with an acceptable diameter.

[0012] In a further aspect, a method for guiding a power cable within a wind turbine is provided. The method includes connecting the power cable to a power component within a nacelle of the wind turbine and positioning the power cable through a central region of a bottom of the nacelle such that the power cable extends substantially vertically downward from the nacelle along the central region of the tower to a first height. The method further includes guiding the power cable from the central region of the tower to an inner wall of the tower near the first height and attaching the power cable to the inner wall of the tower to form a substantially vertical loop.

[0013] In a further aspect, a wind turbine includes a wind turbine rotor including a plurality of rotor blades, a generator operably coupled to the wind turbine rotor to generate electrical power, a power electronic converter for converting the electrical power generated by the generator into converted AC power of a predetermined frequency and voltage, and a wind turbine main transformer having a low-voltage side and a high-voltage side for converting the converted AC power to a higher voltage. The wind turbine further includes a nacelle including the generator, the power electronic converter, and the main transformer, and a tower for rotatably supporting the nacelle. The wind turbine further includes a power cable for electrically connecting the high-voltage side of the main wind turbine transformer to an electrical connection point on a lower portion of the tower. The power cable is disposed downwardly from the nacelle along a central region of the tower, and the power cable includes a vertical power cable loop disposed at least partially along an inner surface of the tower. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram illustrating a perspective view of an example wind turbine. [Figure 2] FIG. 2 is a simplified internal view of an example nacelle of the wind turbine of FIG. 1. [Figure 3A] FIG. 1 is a schematic diagram illustrating an example of power cable placement on a wind turbine tower. [Figure 3B] FIG. 1 is a schematic diagram illustrating an example of power cable placement on a wind turbine tower. [Figure 3C] FIG. 1 is a schematic diagram illustrating an example of power cable placement on a wind turbine tower. [Figure 4] 10A and 10B show schematic diagrams of further examples of cable arrangements on wind turbine towers; DETAILED DESCRIPTION OF THE INVENTION

[0015] Reference will now be made in detail to the embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is presented by way of explanation of the invention, not as a limitation of the invention. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield yet a further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0016] FIG. 1 is a perspective view of an example wind turbine 10. In this example, wind turbine 10 is a horizontal axis wind turbine. Alternatively, wind turbine 10 may be a vertical axis wind turbine. In this example, wind turbine 10 includes a tower 100 extending from a support system 14 on ground 12, a nacelle 16 mounted to tower 100, and a rotor 18 coupled to nacelle 16. Rotor 18 includes a rotatable hub 20 and at least one rotor blade 22 coupled to and extending outward from hub 20. In this example, rotor 18 has three rotor blades 22. In alternative embodiments, rotor 18 includes more or fewer than three rotor blades 22. Tower 100 may be fabricated from tubular steel to define a cavity (not shown in FIG. 1 ) between support system 14 and nacelle 16. In alternative embodiments, tower 100 is any suitable type of tower having any suitable height. According to alternatives, the tower may be a hybrid tower comprising a concrete section and a tubular steel section, or the tower may be a partial or full lattice tower.

[0017] The rotor blades 22 may be spaced about the hub 20 to facilitate rotation of the rotor 18 so that kinetic energy can be transferred from the wind to usable mechanical energy and subsequently to electrical energy. The rotor blades 22 are mated to the hub 20 by coupling blade root portions 24 to the hub 20 at a plurality of load transfer regions 26. The load transfer regions 26 may include hub load transfer regions and blade load transfer regions (both not shown in FIG. 1 ). Loads induced in the rotor blades 22 are transferred to the hub 20 through the load transfer regions 26.

[0018] In examples, rotor blades 22 may have lengths ranging from about 15 meters (m) to about 90 m or more. Rotor blades 22 may have any suitable length that enables wind turbine 10 to function as described herein. For example, non-limiting examples of blade lengths include lengths of 20 m or less, or lengths of 37 m, 48.7 m, 50.2 m, 52.2 m, or greater than 91 m. When wind strikes rotor blades 22 from wind direction 28, rotor 18 rotates about rotor axis 30. As rotor blades 22 rotate and experience centrifugal forces, rotor blades 22 also experience various forces and moments. Thus, rotor blades 22 may deflect and / or rotate from a neutral or unbiased position to a biased position.

[0019] Additionally, the pitch angles of the rotor blades 22, i.e., the angles that determine the orientation of the rotor blades 22 relative to the wind direction, may be varied by a pitch system 32 to control the load and power generated by the wind turbine 10 by adjusting the angular position of at least one rotor blade 22 relative to the wind vector. A pitch axis 34 of the rotor blade 22 is also shown. During operation of the wind turbine 10, the pitch system 32 may particularly vary the pitch angles of the rotor blades 22 such that the angle of attack of (a portion of) the rotor blades is reduced, thereby facilitating a reduction in rotational speed and / or facilitating stalling of the rotor 18.

[0020] In this example, the blade pitch of each rotor blade 22 is individually controlled by the wind turbine controller 36 or pitch control system 80. Alternatively, the blade pitch for all rotor blades 22 may be controlled simultaneously by the control system.

[0021] Additionally, in this example, as wind direction 28 changes, the yaw direction of nacelle 16 may be rotated about yaw axis 38 to position rotor blades 22 relative to wind direction 28 .

[0022] In this example, wind turbine controller 36 is shown as being centralized within nacelle 16, but wind turbine controller 36 may be a distributed system throughout wind turbine 10, on support system 14, within a wind farm, and / or at a remote control center. Wind turbine controller 36 includes a processor 40 configured to perform the methods and / or steps described herein. Additionally, many of the other components described herein include a processor.

[0023] As used herein, the term "processor" is not limited to integrated circuits referred to in the art as computers, but refers broadly to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application specific integrated circuits, and other programmable circuits, and these terms are used interchangeably herein. It should be understood that a processor and / or control system may also include memory, input channels, and / or output channels.

[0024] 2 is an enlarged cross-sectional view of a portion of wind turbine 10. In this example, wind turbine 10 includes a nacelle 16 and a rotor 18 rotatably coupled to nacelle 16. More specifically, a hub 20 of rotor 18 is rotatably coupled to an electric generator 42 positioned within nacelle 16 by a main shaft 44, a gearbox 46, a high-speed shaft 48, and a coupling 50. In this example, main shaft 44 is disposed at least partially coaxially with a longitudinal axis (not shown) of nacelle 16. Rotation of main shaft 44 drives gearbox 46, which in turn drives high-speed shaft 48 by converting the relatively slow rotational motion of rotor 18 and main shaft 44 into relatively faster rotational motion of high-speed shaft 48. The latter is connected to generator 42 for producing electrical energy with the aid of coupling 50. Additionally, a transformer 90 and / or appropriate electronics, switches, and / or inverters may be disposed within the nacelle 16 to convert the electrical energy generated by the generator 42 having a voltage of 400V to 1000V into electrical energy having a medium voltage (e.g., 10 to 35 kV) or a higher voltage, e.g., 66 kV. The electrical energy is conducted from the nacelle 16 to the tower 100 via a power cable 160.

[0025] The gearbox 46 within the transformer 90, the generator 42, may be supported by the main support structure frame of the nacelle 16, which may optionally be embodied as the main frame 52. The gearbox 46 may include a gearbox housing connected to the main frame 52 by one or more torque arms 103. In this example, the nacelle 16 also includes a main forward support bearing 60 and a main aft support bearing 62. Additionally, the generator 42 may be mounted to the main frame 52 by an isolation support means 54, particularly to prevent vibrations of the generator 42 from being introduced into the main frame 52 and thereby creating a source of noise emissions.

[0026] Optionally, the main frame 52 is configured to carry the weight of the rotor 18 and nacelle 16 components, as well as the overall loads caused by wind and rotational loads, and to introduce these loads into the tower 100 of the wind turbine 10. The rotor shaft 44, the generator 42, the gearbox 46, the high-speed shaft 48, the coupling 50, and any associated fastening, supporting, and / or securing devices, including, but not limited to, the supports 52, the forward support bearing 60, and the aft support bearing 62, may be referred to as a drive train 64.

[0027] The nacelle 16 may also include a yaw drive mechanism 56 that can be used to rotate the nacelle 16, and thus the rotor 18, about the yaw axis 38 to control the balance of the rotor blades 22 relative to the wind direction 28.

[0028] To properly position the nacelle 16 relative to the wind direction 28, the nacelle 16 may also include at least one meteorological measurement system, which may include a wind vane and an anemometer. The meteorological measurement system 58 may provide information, which may include the wind direction 28 and / or wind speed, to the wind turbine controller 36. In this example, the pitch system 32 is at least partially disposed within the hub 20 as a pitch assembly 66. The pitch assembly 66 includes one or more pitch drive systems 68 and at least one sensor 70. Each pitch drive system 68 is coupled to a respective rotor blade 22 (shown in FIG. 1 ) to modulate the pitch angle of the rotor blade 22 along the pitch axis 34. Only one of the three pitch drive systems 68 is shown in FIG. 2 .

[0029] In this example, pitch assembly 66 includes at least one pitch bearing 72 coupled to hub 20 and each rotor blade 22 (shown in FIG. 1 ) to rotate each rotor blade 22 about pitch axis 34. Pitch drive system 68 includes a pitch drive motor 74, a pitch drive gearbox 76, and a pitch drive pinion 78. Pitch drive motor 74 is coupled to pitch drive gearbox 76 such that pitch drive motor 74 imparts mechanical power to pitch drive gearbox 76. Pitch drive gearbox 76 is coupled to pitch drive pinion 78 such that pitch drive pinion 78 is rotated by pitch drive gearbox 76. Pitch bearing 72 is coupled to pitch drive pinion 78 such that rotation of pitch drive pinion 78 causes rotation of pitch bearing 72.

[0030] Pitch drive system 68 is coupled to wind turbine controller 36 to adjust the pitch angle of rotor blades 22 upon receiving one or more signals from wind turbine controller 36. In this example, pitch drive motor 74 is any suitable motor driven by an electrical and / or hydraulic system that enables pitch assembly 66 to function as described herein. Alternatively, pitch assembly 66 may include any suitable structure, configuration, arrangement, and / or components, such as, but not limited to, hydraulic cylinders, springs, and / or servo mechanisms. In certain embodiments, pitch drive motor 74 is driven by the rotational inertia of hub 20 and / or energy extracted from a stored energy source (not shown) that provides energy to components of wind turbine 10.

[0031] Pitch assembly 66 may also include one or more pitch control systems 80 for controlling pitch drive systems 68 according to control signals from wind turbine controller 36 for certain priority conditions and / or during overspeed of rotor 18. In this example, pitch assembly 66 includes at least one pitch control system 80 communicatively coupled to each pitch drive system 68 for controlling pitch drive systems 68 independently from wind turbine controller 36. In this example, pitch control system 80 is coupled to pitch drive systems 68 and sensors 70. During normal operation of wind turbine 10, wind turbine controller 36 may control pitch drive systems 68 to adjust the pitch angle of rotor blades 22.

[0032] According to one embodiment, power supply 84, comprising, for example, a battery, an electrical capacitor, or an electrical generator powered by rotation of hub 20, is disposed on or within hub 20 and is coupled to sensor 70, pitch control system 80, and pitch drive system 68 to provide a source of electrical power to these components. In this example, power supply 84 provides a continuous source of electrical power to pitch assembly 66 during operation of wind turbine 10. In an alternative embodiment, power supply 84 provides electrical power to pitch assembly 66 only during a power loss event of wind turbine 10. A power loss event may include a loss or degradation of the electrical grid, a malfunction of the electrical system of wind turbine 10, and / or a failure of wind turbine controller 36. During a power loss event, power supply 84 operates to provide electrical power to pitch assembly 66 so that pitch assembly 66 can operate during the power loss event.

[0033] In this example, pitch drive system 68, sensor 70, pitch control system 80, cables, and power supply 84 are each positioned within a cavity 86 defined by an inner surface 88 of hub 20. In alternative embodiments, the components may be positioned relative to and directly or indirectly coupled to the outer surface of hub 20.

[0034] 3A-3C schematically illustrate an example of a power cable arrangement on a wind turbine tower. In one aspect of the present disclosure, a tower 100 for a wind turbine includes a top portion 102 that supports a nacelle 16 of the wind turbine about a yaw axis 38. The nacelle 16 includes power components and a power cable 200 for electrically connecting the power components to electrical connection points on a lower portion of the tower. The power cable 200 extends downward from the nacelle along at least a substantially central region of the tower 100 to a first height H1. At substantially the first height H1, the power cable 200 includes a power cable loop, the power cable loop including an upward curve and a downward curve. The power cable loop includes a movable cable portion 235 and a fixed cable loop 230. The fixed cable portion 235 includes at least a portion 220 of the downward loop.

[0035] In this example, the movable cable part 235 comprises a movable downward section 233 and a (trailing) movable upward section 237. The fixed cable part 230 is attached to the end of the movable upward section 237.

[0036] In this example, the fixed cable portion 230 comprises at least an upward portion 210 and a downward portion 220. The upward portion 210 of the power cable loop 230 is disposed along the inner surface of the tower 100 herein.

[0037] In this example, the movable upward portion 237 and the fixed upward portion 210 together form an upward curve. The power cable loop is completed by the movable downward portion 223, which together with the fixed downward portion 220 forms a downward curve.

[0038] A movable cable section, as used throughout this disclosure, can be considered to be a portion of a cable loop that is not fixed in a fixed position, but instead is movably arranged so as to be able to accommodate movement of the power cables, in particular shortening of the power cables and / or twisting of the power cables caused by yaw of the nacelle. A fixed cable loop, as used throughout this disclosure, can be considered to be a portion of a cable loop that is fixed in a fixed position and therefore not specifically configured to accommodate twisting and / or shortening of the cables by changing its position or orientation.

[0039] Herein, the power component located in the nacelle 16 may be the generator or power electronic converter of the wind turbine. The tip 201 of the power cable 200 may be connected to the generator or power electronic converter. The electrical connection point on the lower part of the tower (i.e., below the power cable loop) may be at or near the bottom of the tower and may be the power electronic converter or the main wind turbine transformer.

[0040] Alternatively, the power component located in the nacelle 16 may be a main wind turbine transformer, and the tip 201 of the power cable 200 may be connected to the main wind turbine transformer, in particular to the high voltage side of the main wind turbine transformer. An electrical connection point on a lower part of the tower, for example at or near the bottom of a section of the tower, may be an electrical connection to the wind park power grid. The electrical connection may be via, for example, a switchgear.

[0041] 3A, the downwardly directed portion 220 of the fixed cable section is disposed along the inner surface of the tower 100. The movable cable section 235 of the power cable 200 extends from the central region of the tower towards the inner wall of the tower and can be considered to form part of the same power cable loop.

[0042] The inner surface of tower 100 may be formed by the inner wall surface of the turbine tower. Fixed power cable section 230 may be positioned near the inner wall of the wind turbine tower, thus maximizing the space available for movable cable loop 235. Fixed power cable section 230 may extend along the inner wall of the tower while maintaining a substantially constant distance from the inner wall. Fixed power cable section 230 may also be attached to at least one other fixed structure attached to the inner wall. Such fixed structure may include a portion of a ladder.

[0043] The upwardly directed and downwardly directed portions 210, 220 of the fixed power cable section 230 may be positioned along the interior surface of the tower using, for example, a plurality of cable cleats 280. A cable cleat may be considered herein to be any mechanical assembly suitable for securing, clamping, and / or supporting a cable.

[0044] In an example, as shown in FIGS. 3A-3C, a fixed vertical power cable loop may be secured to the inside of a wind turbine tower using four to eight cable cleats 280.

[0045] 3A-3C, one or more of the cable cleats 280 may be connected to a mounting bracket 290 attached to the interior surface of the tower. The bracket 290 may be configured to allow for the mounting of the cable cleats 280 at multiple heights along the bracket using any suitable fasteners, such as nuts and bolts. Such a bracket may be attached to a boss on the interior surface of the tower.

[0046] In other examples, other cleats, cable clamps or assemblies for securing cables may be used, such as cable ladders or cable trays.

[0047] The first height H1 at which the fixed power cable loop 230 is positioned may be determined such that the power cable 200 positioned between the first height H1 and the nacelle 16 is configured to absorb the maximum amount of yaw of the nacelle in a single direction.

[0048] The electric cable may have a certain twisting capacity. For example, the power cable 200 may have a twisting capacity of, for example, 70 to 100 degrees per meter, approximately 80 degrees per meter in this example. The maximum twist that the power cable 200 may have to withstand may be 1080 degrees (three full rotations of the nacelle) or 1440 degrees (four full rotations of the nacelle). The first height H1 at which the power cable loop is located may be determined so that the length of the power cable between the nacelle and the first height is sufficient to absorb the maximum allowable twist. The determination of the first height may further take into account a safety factor. The first height may be, for example, 14 meters or lower below the nacelle, specifically at least 17 meters below the nacelle. Because the power cable loop 230 itself may not be able to absorb any twist, any twist may have to be absorbed upward by the power cable loop 230.

[0049] Wind turbine tower 100 may further include a platform 268 at or near the first elevation. Platform 268 may be configured to support personnel and allow personnel access for maintenance and installation purposes. Multiple platforms 248, 258 may be located at different elevations to allow personnel to perform installation, inspection, and / or maintenance tasks.

[0050] Platform 268 may include a cylindrical portion 270 that allows cables to pass through the platform. The geometric center of cylindrical portion 270 may substantially coincide with the geometric portion of the wind turbine tower at the elevation of platform 268.

[0051] Also, as shown in the example of Figures 3A-3C, an elevator shaft 250 (in which a ladder may also be located, as seen in Figure 3B) may be formed next to the platform 268 so that personnel can reach the platform 268 using a ladder 250 or elevator (not shown).

[0052] In the example of Figure 3A, the platform 268 may include recesses 272, 277 near the inner surface of the wind turbine tower for placing the power cable 200. In the example of Figure 3A, a first substantially rectangular cutout 272 is provided near a corner of the platform 268. The upwardly facing portion 210 of the fixed cable portion 230 is placed through this cutout 272. Apart from the power cable 200, further auxiliary cables (shown particularly with reference to Figure 4) may be placed through the same cutout 272.

[0053] The downwardly facing portion 220 of the fixed cable portion 230 may be guided through a smaller substantially rectangular cutout 277 .

[0054] In the example of Figure 3, the moving cable section extends substantially in the vertical longitudinal plane of the tower. In other examples, the moving cable loop may also extend partially in the azimuth direction (about the yaw or longitudinal axis of the tower). In these cases, the entire moving cable section of the power cable loop is not located substantially in the same longitudinal plane. Combining vertical and azimuth extensions can increase the extensibility of the moving cable configured to accommodate cable movement, or reduce the vertical extension of the moving cable section.

[0055] In the examples disclosed herein, fixed cable section 230 is shown as being primarily vertical, including upward and downward portions. However, in other examples, fixed cable section 230 may extend primarily along an azimuthal plane rather than vertically. Fixed cable section 230 may be disposed on the interior wall of the tower at a substantially constant height.

[0056] 3A, there may be additional auxiliary cables extending between the nacelle 16 and the bottom of the tower, and additional cable guide assemblies 260 for guiding the power cables 200 and the auxiliary cables. The cable guide assemblies 260 may be arranged as cable spacers to ensure an appropriate distance between the different cables.

[0057] Beyond the fixed cable portion 230, further toward the bottom of the tower, the cable arrangement may be fixed. The fixed cable portion 310 of the power cable 200 and / or the auxiliary cable may generally be guided along the inside of the wind turbine tower. The fixed cable portion 310 may include a different cable than the freely hanging portion 350 of the cable. As used throughout this disclosure, the freely hanging or moving portion 350 of the cable may be considered a portion of the cable configured to receive and absorb movement, and for this purpose has a certain slack. That is, in contrast to the fixed cable portion 310, the freely hanging portion is not rigidly fixed in place, but instead can move within the tower, particularly in response to yawing movement of the nacelle. It should be noted that, although the fixed cable portion is denoted herein by reference numeral 310 as extending downward from the platform 268, the moving cable portion 235 of the power cable loop may be disposed at least partially below the platform 268.

[0058] The cable guide assembly may have a variety of different configurations and sizes depending on particular needs. Such a cable guide assembly 260 may have a circular central portion or through-hole with an outwardly facing convex surface and several radially extending fingers.

[0059] Spaces may be disposed between adjacent fingers to receive auxiliary cables. The auxiliary cables may include electrical cables for power supply and / or communication cables for auxiliary systems of the wind turbine. The auxiliary systems of the wind turbine that receive power may include a pitch system, a yaw system, a beacon, an air conditioning system, etc. The communication cables may include fiber optic cables, signal cables, etc.

[0060] To keep such auxiliary cables rigidly within the allocated spaces, clamps may be placed within the spaces. Depending on the type of cable placed in each space, the number and type of clamps may be adapted to hold the cables rigidly in their positions. It is not necessary to clamp all cables. Cable selection may be free within those allocated spaces.

[0061] In the example, the power cable 200 is not constrained by the cable guide assemblies, i.e., the power cable can twist and move vertically relative to one or more of the cable guide assemblies 260, and in particular, relative to all of the cable guide assemblies 260.

[0062] Multiple cable guide assemblies 260 may be positioned above one another. Typically, the cables may extend through the tower from (or to) the nacelle in a substantially central region of the wind turbine tower. The cable guide assemblies 260 may be spaced apart from one another by, for example, 50 to 150 cm, specifically 70 cm to 1 meter.

[0063] Selection of cable guide assemblies 260 above the first distance, i.e., along the free-hanging portion 350 of the cable, may be capable of rotating (to accommodate twisting) and translating along the vertical direction (to accommodate shortening of the cable). Selection of cable guide assemblies 260 may only translate and not rotate. One or more of the cable guide assemblies 260 may be fixed in position or may be arranged to "float" around the cable, i.e., simply guide the cable without significantly constraining the cable.

[0064] For example, a cable guide assembly 260 arranged to move along a cylindrical portion 270 of a platform 268 is only permitted to translate (move vertically).

[0065] In this regard, cable guide assembly 260 configured to be received within and guided by cylindrical portion 270 may differ slightly from other cable guide assemblies disposed thereon. In particular, cable guide assembly 260 may have a plurality of protrusions that are guided by slots in cylindrical portion 270 to prevent rotational movement.

[0066] A wind turbine tower may be formed by multiple tower sections stacked on top of each other. These tower sections may be formed as substantially cylindrical sections or, for example, as frustoconical sections. In some cases, the tower sections may have polygonal peripheries. Cables, including power cable 200, may be positioned near the geometric center of the tower at each cross section between the power cable loop and the nacelle. Such a central positioning is useful for absorbing twisting caused by yaw of the nacelle.

[0067] In one aspect of the present disclosure, a method for guiding a power cable within a wind turbine is provided. The method includes connecting a power cable 200 to power components within a nacelle 16 of the wind turbine (see FIGS. 3A-3C ). Then, the method includes placing the power cable 200 through a central region of a bottom of the nacelle 16 such that the power cable 200 extends substantially vertically downward from the nacelle 16 along the central region of the tower 100 to a first height H1. The method further includes guiding the power cable from the central region of the tower to an inner wall of the tower near the first height H1, and attaching the power cable 200 to the inner wall of the tower to form a substantially vertical loop.

[0068] A portion of the vertical loop may be attached to an interior wall of the tower, and another portion of the vertical loop may be formed by a moving or freely hanging cable section.

[0069] In an example, directing power cable 200 from the central region may include loosely placing power cable 200 through a portion of platform 268 and guiding the power cable toward the interior wall of the tower. Power cable 200 may be guided through a central portion 270 of platform 268 and then guided up to the wall of the tower and through a cutout in the platform.

[0070] In an example, the method may further include positioning the auxiliary cable substantially parallel to the power cable along a central region of the tower, and guiding the power cable and the auxiliary cable within the same cable guide assembly 260.

[0071] At or near the first height H1, the auxiliary cable may include an auxiliary cable loop 330, which may be positioned separately from the power cable loop. The auxiliary power cable loop 330 may also be vertically positioned and include upward and downward portions, and specifically, these upward and downward portions may be attached to the interior wall of the tower.

[0072] Figure 4 shows a further example of cables arranged on a wind turbine tower, in a schematic way, in which both power and auxiliary cables are shown.

[0073] In a further aspect of the present disclosure, with reference to Figures 1, 2, and 5, a wind turbine is provided. The wind turbine comprises a wind turbine rotor 18 including a plurality of rotor blades 22, and a generator 42 operably coupled to the wind turbine rotor 18 for generating electrical power. The wind turbine further comprises a power electronic converter for converting electrical power generated by the generator 42 into converted AC power of a predetermined frequency and voltage, and a wind turbine main transformer having a low voltage side and a high voltage side for converting the converted AC power to a higher voltage.

[0074] The wind turbine 10 comprises a nacelle 16 which includes or houses a generator 42 , a power electronic converter and a main transformer, and a tower 100 for rotatably supporting the nacelle 16 .

[0075] Wind turbine 10 further includes a power cable 200 for electrically connecting the high voltage side of the main wind turbine transformer to an electrical connection point on the lower portion of tower 100. Power cable 200 is disposed downwardly from nacelle 16 along a central region of tower 100, with power cable 200 comprising a vertical power cable loop disposed at least partially along the inner surface of tower 100.

[0076] In this example, power cable 200 is connected to the high voltage side of the main wind turbine transformer. Power cable 200 may be configured to transmit power at a voltage of 10 kV or greater, specifically 30 kV or greater, and more specifically 60 kV or greater, when delivered to the high voltage side of the main wind turbine transformer.

[0077] The power cable 200 in any of the examples disclosed herein may include a single phase of electrical connection, or in this particular example, the power cable may include multiple phases, for example, three or six phases.

[0078] The minimum bend radius of the power cable 200 in the freely hanging or flexible portion in any of the examples disclosed herein may be at least 0.75 meters, specifically at least 0.9 meters, or even 1 meter or more. Due to the minimum bend radius of the power cable 200, there may not be enough space at height H1 to place a classic cable saddle. The cable power loop 200, which takes into account the minimum bend radius, may be placed along the inner surface of the tower.

[0079] The vertical power cable loop includes upward and downward portions, and one or more of the upward and downward portions of the power cable loop may be attached to the inner surface of the tower using, for example, a cable cleat attached to a bracket. The fixed cable section 230 in this case includes the upward and downward portions of the power cable loop. The bracket may be attached to one or more bosses on the inner surface of the tower. Other fasteners may also be used.

[0080] The auxiliary cable may be positioned generally parallel to the power cable 200 along the free-hanging portion 350 of the cable, specifically above the platform 268 and generally along the central region of the tower. Any twisting and shortening of the cable can be absorbed by the free-hanging portion 350.

[0081] At or near the platform 268, the auxiliary cable on the one hand and the power cable 200 on the other hand may be separated from each other. The auxiliary cable may have a different, in particular a smaller, minimum bend radius than the power cable 200. The auxiliary cable may therefore have a different cable loop, in particular a vertical auxiliary cable loop 330. The downward portion 279 of the auxiliary cable may be guided along the tower, in particular along or near the elevator shaft.

[0082] At the fixed portion 310 of the cable, specifically below the cable loop, the power cable 200 may be positioned parallel to the auxiliary cable. A number of clamps or cleats may be positioned with the wind turbine tower to secure the power cable and auxiliary cable in place.

[0083] At multiple locations along the wind turbine tower and / or at multiple locations along a substantially horizontal direction (particularly between the nacelle and the platform near the cable loop), cable organizers (also known as "cable spacers"), or cable guide assemblies, may be positioned so that the cables are arranged substantially parallel to one another.

[0084] Throughout this disclosure, reference is made to power cables. The dimensions and materials of power cables may vary. For example, copper high and medium voltage power transmission cables (MVhigh cables, 20-35 kV) may be, for example, 60-120 mm long. 2 The minimum bend radius of a power cable may depend, inter alia, on the voltage rating and the insulating material required for a particular power and / or voltage rating. The minimum bend radius may be, for example, 75 cm or more, specifically 90 cm or more, or even 1 meter or more. These minimum bend radii may apply to freely hanging or movable portions of the cable. The minimum bend radius of the same power cable may be smaller for fixed portions of the cable. Such a minimum bend radius may be, for example, 65 cm or more, specifically 75 cm or more, or more specifically 85 cm or more.

[0085] According to additional or alternative embodiments, the electrical energy produced by the generator with a voltage of 400V to 1000V is guided through the tower to power components, switches, and / or transformers to be converted to medium voltage (10 to 35 kV) by said components located lower than the nacelle.

[0086] While only a few examples are disclosed herein, other alternatives, modifications, uses, and / or equivalents thereof are possible. Moreover, all possible combinations of the described examples are also covered. Accordingly, the scope of the present disclosure should not be limited by the specific examples, but should be determined solely by a fair reading of the appended claims. [Explanation of symbols]

[0087] 10. Wind Turbines 12 Ground 14 Support System 16 Nacelle 18 Wind Turbine Rotor 20 Hub 22 rotor blades 24 Blade base 26 Load Transfer Area 28 Wind direction 30 rotor shaft 32 Pitch System 34 Pitch axis 36 Wind Turbine Controller 38 Yaw axis 40 processors 42 Electric Generator 44 Main shaft, rotor shaft 46 Gearbox 48 High Speed ​​Shaft 50 Coupling 52 Main frame, support 54 Separation support means 56 Yaw drive mechanism 58 Weather Measurement System 60 Main forward support bearing 62 Main rear support bearing 64 Drivetrain 66 Pitch Assembly 68 Pitch Drive System 70 sensors 72 Pitch bearing 74 Pitch drive motor 76 Pitch drive gearbox 78 Pitch drive pinion 80 Pitch Control System 84 Power supply 86 Cavity 88 Inner 90 Transformer 100 Wind Turbine Tower 102 Top 103 Torque arm 200 Power Cable, Cable Power Loop 201 Tip 210 Upward part 220 Downward part 230 Fixed power cable section, fixed power cable portion, fixed power cable loop 235 Movable cable section, movable cable loop, fixed cable section 237 Movable upward part 248 Platform 250 Elevator shaft, ladder 258 Platform 260 Cable guide assembly 268 Platform 270 Central part, cylindrical part 272 Notches and recesses 277 Notches and recesses 279 Downward part 280 Cable Cleat 290 Mounting Bracket 310 Fixed cable part 330 Auxiliary Power Cable Loop 350 Freely suspended parts, movable parts

Claims

1. A tower (100) for a wind turbine (10), comprising: a top portion (102) supporting a nacelle (16) of the wind turbine (10) about a yaw axis (38), the nacelle (16) including power components; a power cable (200) for electrically connecting the power components to an electrical connection point at the bottom of the tower (100); Equipped with the power cable (200) extends downwardly along a substantially central region of the tower (100) from the nacelle (16) and includes a power cable loop including an upward curve and a downward curve at a first height (H1) between the nacelle (16) and the electrical connection point; the power cable loop comprises a movable cable portion (235) and a fixed cable portion (230), the fixed cable portion (230) comprising at least a portion of the downward curve; The fixed cable portion (230) comprises at least an upward portion (210) and a downward portion (220); A tower (100) for a wind turbine (10), wherein the upwardly extending portion (210) of the fixing cable portion (230) is disposed along an inner surface of the tower (100).

2. 2. The tower (100) of claim 1, wherein the movable cable loop (235) comprises a movable upward portion (237), and the fixed cable loop (230) is attached to an end of the movable cable loop (235).

3. A tower (100) as described in claim 1, wherein the downward portion (220) of the fixed cable portion (230) is positioned along the inner surface of the tower (100).

4. The tower (100) of claim 1, wherein the movable cable portion (235) extends substantially within a vertical longitudinal plane of the tower (100).

5. The tower (100) of claim 1, wherein the movable cable portion (235) extends at least partially in an azimuth direction.

6. The tower (100) of claim 1, wherein the electrical connection point is at or near a bottom of the tower (100).

7. 2. The tower (100) of claim 1, wherein the first height (H1) is determined such that the power cable (200) disposed between the nacelle (16) and the first height (H1) is configured to absorb a maximum amount of yaw of the nacelle (16) in a single direction.

8. The tower (100) of claim 1, further comprising a platform (268) at or near the first height (H1).

9. The tower (100) of claim 1, wherein the power component is a main transformer of the wind turbine (10).

10. 2. The tower (100) of claim 1, further comprising a plurality of auxiliary cables (263) extending between the nacelle (16) and a lower portion of the tower (100), and further comprising a cable guide assembly (260) that guides the power cable (200) and the auxiliary cables (263).

11. The tower (100) of claim 10, wherein the auxiliary cable (263) comprises an electrical cable for power supply and / or a communication cable for auxiliary systems of the wind turbine (10).

12. The tower (100) of claim 10, wherein the power cable (200) is disposed in a central through hole (262) of the cable guide assembly (260).

13. The tower (100) of claim 1, wherein the power cable (200) is configured to transmit power at a voltage of 20 kV or more, specifically 30 kV or more, more specifically 60 kV or more.

14. The tower (100) of claim 1, wherein the minimum bending radius of the power cable (200) at the movable cable section (235) is at least 0.7 meters, particularly at least 0.9 meters or more.

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