Stator winding arrangement for wind turbine generator, wind turbine generator, wind turbine and method for manufacturing stator winding arrangement

Abstract

A stator winding arrangement (1) for a wind turbine generator (25) comprises at least one electrical conductor (3) forming turns of at least one coil extending in a geometry with at least one bend (6, 14), where the minimum bend radius of each bend (6, 14) is in the range of from 25 to 35 mm, and an inter-turn insulator (7) extending around the conductor (3), the turn-to-turn insulator (7) comprises at least one layer (11, 12, 13) of mica insulating tape (8) wound around the conductor (3) at least at the at least one bend (6, 14).

Description

Technical Field

[0001] The present invention relates to a stator winding arrangement for a generator of a wind turbine, comprising at least one electrical conductor forming turns of at least one coil and an inter-turn insulation extending around the conductor, wherein the coil extends in a geometry having at least one bend. The invention also relates to a wind turbine generator, a wind turbine, and a method for producing a stator winding. Background Art

[0002] In a wind turbine, a large, heavy generator is used to convert the mechanical energy from the wind into electrical energy, which can be fed into a power grid and / or used to operate one or more devices in the wind turbine. A wind turbine generator typically includes a rotor coupled to a rotor hub to which a plurality of wind turbine blades are attached. Wind impinging on the blades causes the rotor to rotate relative to the stator of the wind turbine. The stator includes stator windings, in which the magnets of the rotor induce currents. Power electronics (e.g., converters) are provided to convert the electrical energy generated in the stator windings into electrical energy that can be further used, for example, to be fed into a power grid. The rotor can be an inner rotor (with an outer stator surrounding it) or, in a direct-drive wind turbine, an outer rotor rotating around an inner stator, which is a preferred variant.

[0003] Regarding wind turbine generator stators, it has been proposed to construct the stator from multiple stator segments, each of which can have a separate stator winding. The stator winding can form coils, in particular, at least one coil per phase. In most cases, a three-phase generator is used. The coils can be connected in series and / or in parallel. The conductors of the stator windings typically run around the stator teeth in multiple turns to form the coils, resulting in a specific conductor geometry. This geometry is dictated by spatial and functional constraints. These constraints can be particularly narrow in single-layer windings.

[0004] Geometric limitations in the prior art lead to the use of insulating materials that ensure good mechanical properties. A distinction is made here between interturn insulation, which directly surrounds the conductor and insulates adjacent conductor segments of the other turns of the coil, and coil insulation ("main wall insulation"), which surrounds the group of conductor segments that form all the turns of the coil. Conventional insulating materials used for interturn insulation of the coil's conductors are polyimide materials, such as those commonly referred to commercially as "Kapton." Polyimide materials have good mechanical properties, preventing cracks from forming in the interturn insulation during the bending and / or coiling steps in manufacturing and / or when subjected to stress in use. However, the thermal properties and dielectric strength of polyimide materials may be acceptable, but not outstanding.

[0005] Polyimide materials offer a good option for simplifying the manufacture of stator winding arrangements for wind turbine generators, as precise control of coil manufacturing is not required. The mechanical strength against unwanted cracking allows for easy handling of the stator windings and coils, in particular allowing the use of a wide range of handling operations and tools.

[0006] Modern wind turbines deliver increasing amounts of electrical power. This power increase translates directly to wind turbine generators, which must be designed for the resulting operating conditions. In particular, higher temperatures, higher voltages, and higher currents can occur in these high-power applications. Consequently, improvements must also be made to the electrical and thermal performance of insulation components.

[0007] It is therefore an object of the present invention to provide an interturn insulation in a stator winding that is improved with respect to electrical and thermal performance, while still being able to handle the geometrical constraints and mechanical loads that occur during manufacture and use. Summary of the Invention

[0008] This object is achieved by providing a stator winding arrangement, a wind turbine generator, a wind turbine and a method for manufacturing a stator winding according to the independent claims.The dependent claims describe advantageous embodiments.

[0009] In the stator winding as initially described, according to the invention, the minimum bending radius of each bend is in the range from 25 to 35 mm, and the interturn insulation comprises at least one layer of mica insulating tape wound around the conductor at least at at least one bend.

[0010] Within the present invention, two factors are relevant to providing improved interturn insulation for stator windings in wind turbines: the insulating material and the winding geometry with respect to the conductor bends. These factors are interrelated and should work together to provide an improved solution. According to the present invention, it was surprisingly discovered that, despite mechanical performance limitations, mica-based materials can be used even in particularly restricted environments requiring specific geometries, as long as the radius of the main bends is within the range of 25 to 35 mm. This combination of material and geometry results in a reduced risk of failures, particularly due to mechanical damage, during coiling and / or bending operations, as well as in the final turns. Since all insulating materials used in the present invention are mica-based and therefore compatible, the solution improves electrical insulation and thermal performance.

[0011] Furthermore, the invention allows for an improved continuous manufacturing, thereby allowing for a high reproducibility in terms of quality and correct dimensions of the coils. Advantageously, mica-based materials are also available at reduced costs compared to polyimide materials.

[0012] In a particularly advantageous embodiment, the mica insulating tape may include a mica sublayer backed on one side by a thinner PET sublayer. Such mica insulating tapes are already known in the art and include a so-called PET backing to provide strength and improve handling. Furthermore, a pure PET layer can be used directly on the conductor as a base. Preferably, the PET layer is solid, i.e., it does not have any textile structure or otherwise include cavities or openings. Therefore, it cannot be saturated, for example, during VPI (vacuum pressure impregnation) or other impregnation processes of the entire coil (such processes are generally not applied to bends).

[0013] From an electrical perspective, the interturn insulation must be strong enough, and in particular, thick enough, to provide sufficient dielectric strength to withstand the voltage differences that occur between the different turns of the coil. Therefore, more than one layer of mica tape may be required. Typically, the thickness of the mica tape can be 0.1 to 0.5 mm. Depending on the specific configuration and characteristic parameters of the wind turbine generator, it has generally been found that two to four layers of mica tape provide the necessary dielectric strength and significantly improve insulation conditions and thermal behavior compared to known solutions.

[0014] Typically, to manufacture coils, an already insulated conductor is bent to form the corresponding turns (loops) of the coil. This process is also known as "coiling." In-depth analysis has shown that friction between turns and between different layers is a highly correlated stress phenomenon that can lead to cracks and wrinkles in the interturn insulation.

[0015] Therefore, in a preferred embodiment, the insulation can include an inner layer of pure PET tape and multiple layers, particularly two to four layers, of mica tape, with the different layers stacked so that each mica sublayer is positioned between PET materials. Thus, for example, pure PET tape, which does not include mica, can be applied directly to a conductor (e.g., copper strands) to serve as a foundation. A first layer of PET-mica tape is added to the pure PET tape, such that the mica sublayer contacts the pure PET tape. The PET sublayer delimits the layer on the outside, such that the mica sublayer is positioned between the PET materials. Here, a second layer of PET-backed mica tape is added in the same configuration as the first layer, such that the outer PET sublayer of the first layer and the inner mica sublayer of the second layer abut at the boundary. This configuration is repeated for all other layers, such that each mica sublayer is positioned between PET sublayers. This configuration ensures that the frictional properties of each pair of layers are identical, reducing the occurrence of wrinkles and cracks during bending operations, particularly looping operations. With respect to the adjoining inter-turn insulation, since the outermost sub-layer material is always PET for each turn of the coil (i.e., each conductor segment forming a turn), mechanical protection of the inter-turn insulation is improved. Furthermore, the intersection of the same material gives each inter-turn insulation a similar roughness, thereby facilitating movement during bending (e.g., coil winding). In particular, the identical material at the boundaries of the inter-turn insulation, which may move relative to each other, achieves conditions comparable to material continuity, thereby reducing the risk of mechanical damage during the manufacture of the stator winding arrangement and later during its use, when the coils may be subjected to vibrations and / or other movements, such as those occurring during operation of a wind turbine generator. Here, too, all PET layers may preferably be solid, i.e., non-impregnable.

[0016] In this context, if the interturn insulation comprises multiple layers, in particular two to four layers, of mica tape, the boundaries between adjacent segments of mica tape within a layer are staggered along the conductor. In particular, the mica tape can be wrapped around a conductor of a certain width, resulting in multiple adjacent segments of mica tape along the conductor. If the boundaries are staggered along the stacking direction of the layers, this provides additional mechanical stability and robustness against cracks and wrinkles.

[0017] In an embodiment, the geometry can be a longitudinal shape comprising two longitudinal straight sections, wherein at least one first bend in the at least one bend connects the straight sections at at least one longitudinal end. For example, the geometry can be at least substantially racetrack-shaped, and / or at least one first bend can include a conductor bend angle of at least substantially 180°. In a wind turbine generator, the stator winding arrangement, and thus the coils, can be placed with their straight sections in recesses of the stator, particularly extending along the stator teeth. In the coil overhang region, the straight sections can be connected by a 180° first bend. Alternatives include using multiple first bends with straight sections between them, for example, two 90° first bends with an additional straight section perpendicular to the parallel longitudinal straight sections. In this context, the choice of mica insulating tape and a radius in the range of 25 to 35 mm still allows for the provision of first bends, even in tight and confined environments, while providing improvements in interturn insulation and thermal properties. In particular, a bend of 180° is permitted without mechanical damage if the bend radius is at least 25 mm.

[0018] If more than one phase is used in the stator, the coils of the corresponding phases in the same tooth structure are usually placed overlapping, since the straight sections of each phase follow one another in a staggered manner in a direction perpendicular to the extension of the straight sections. In such an embodiment, but also taking into account other geometric constraints, a second bend can be provided in the more than one bend, which bends the longitudinal end portion out of the plane in which the straight sections extend, in particular at a predetermined bend angle. For example, such a second bend can be used to allow the conductor of its multiple turns to pass through the conductor of the coil of another phase. For example, if the first bend in the stator winding arrangement of the first phase is in a plane, the longitudinal end portion of the coil of the second phase can be bent out of the plane in which the staggered straight sections extend using a corresponding second bend, so that the longitudinal end portion of the coil of the second phase is positioned above or below the longitudinal end portion of the coil of the first phase. Generally speaking, if a first bend and a second bend are used, the bend radius requirements (particularly a minimum bend radius of at least 25 mm) apply to both the first bend and the second bend, and preferably, the first bend and the second bend are provided at a distance from one another, i.e., not combined. For example, a second bend can be provided at the end of a straight section, such that the longitudinal ends of the coil are bent out of the plane in which the straight section extends, in particular into an inclined plane, where at least one first bend is provided for each longitudinal end.

[0019] Preferably, the conductor can comprise copper and / or be a stranded wire, in particular a stranded copper wire. The conductor can have an at least substantially rectangular or circular cross-sectional shape. The conductor segments forming the respective turns and thus extending in parallel can be arranged in any desired layout, for example in an array or matrix of turns of the coil. The arrangement of the turns forming the coil can be further stabilized, maintained, and insulated by a coil insulation, which can also be referred to as a main wall insulation, which encloses all the turns of the conductor in a common insulation structure. This common insulation structure must, of course, be distinguished from the inter-turn insulation proposed in the present invention, which insulates between the conductor segments of different turns.

[0020] The present invention also relates to a wind turbine generator comprising a stator and a rotor, wherein the stator has a plurality of stator winding arrangements according to the present invention. All features and descriptions of the stator winding arrangements can be similarly applied to the wind turbine generator according to the present invention, so that the same advantages can be achieved.

[0021] In particular, the coils of the stator winding arrangement can each include straight sections extending parallel to each other in the stator recess and a first bend connecting the straight sections in the coil overhang region. Stator teeth of the stator tooth structure can extend between adjacent straight sections. In particular, the coil overhang region can include the longitudinal ends mentioned above.

[0022] In a preferred embodiment, multiple stator winding arrangements can be provided for different phases at one of a plurality of tooth structures, wherein the straight sections of the stator winding arrangements extend in parallel, particularly in a staggered manner, with at least one of the stator winding arrangements of each tooth structure being bent such that a second bend is formed in the coil overhang region at a bend angle away from the plane in which the straight sections extend, allowing the stator winding arrangement of another phase to pass through. As discussed above, if the straight sections of respective coils associated with different phases are arranged in a staggered manner within a set of stator winding arrangements associated with a tooth structure, the geometry of the coils of one phase can extend entirely within the plane in which the straight sections extend, while the geometry of the coils of at least one other phase can be bent out of this plane in the coil overhang region to allow the conductors of the coils of the one phase to pass through each other. For example, a predetermined bend angle can be assigned to each phase to allow the coil conductors to pass through each other in the coil overhang region, even when the amount of space is limited.

[0023] Typically, and particularly when the wind turbine generator is used in a direct-drive wind turbine, the stator can be an inner stator surrounded by an outer rotor. However, in other embodiments, the stator can also be an outer stator surrounding an inner rotor. The rotor includes at least one magnet, particularly a permanent magnet, to define corresponding rotor magnetic poles.

[0024] In a wind turbine according to the present invention, a wind turbine generator according to the present invention is provided. Such a wind turbine may be, for example, an offshore wind turbine and / or a direct drive wind turbine.

[0025] The present invention also provides a method for manufacturing a stator winding arrangement for a wind turbine generator, comprising the steps of: - provide electrical conductors, - at least one layer of mica tape wrapped around the conductor as inter-turn insulation, and - bending the conductor into a coil having a plurality of turns and a geometry having at least one bend, wherein the minimum bend radius of each bend is in the range of from 25 to 35 mm.

[0026] Thus, the interturn insulation and radius are selected so that, after adding the interturn insulation, the conductor bending, in particular the coiling, can be carried out without risk of damage due to mechanical stress. The resulting stator winding arrangement, in particular the interturn insulation, also withstands the mechanical stresses that occur during use. In an additional step, external coil insulation ("main wall insulation") can be added, which also stabilizes and protects the coil turns. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other objects and features of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings. However, these drawings are merely schematic diagrams designed for illustration purposes only and do not limit the present invention. The drawings show: Figure 1 is a schematic perspective view of a stator winding arrangement according to the present invention, Figure 2 for Figure 1 A cross section of an embodiment, Figure 3 is an exemplary layer structure of an inter-turn insulation member, Figure 4 is a detailed view of a second embodiment of a stator winding arrangement according to the invention at a longitudinal end portion, Figure 5 is a detailed view of a third embodiment of a stator winding arrangement according to the invention at a longitudinal end portion, Figure 6 a stator winding comprising a plurality of stator winding arrangements according to the invention, Figure 7 A detailed view of the coil overhang area of ​​the stator winding, and Figure 8 is a schematic cross-sectional view of a wind turbine according to the present invention. DETAILED DESCRIPTION

[0028] Figure 1A schematic perspective view of a stator winding arrangement 1 is shown, providing coils for use in a tooth structure of a stator of a wind turbine generator. Figure 1 In FIG, the outer geometry is illustrated; ie only the outer coil insulation 2 (main wall insulation) is shown. Figure 2 Corresponding cross-sectional views are shown, which are merely schematic and may not be drawn to scale. Figure 2 As can be seen from the cross-sectional view, a conductor 3, which has been bent to form a plurality of turns of a coil, is surrounded by a coil insulation 2. The conductor 3 is a stranded copper wire and, in this case, has an at least substantially rectangular cross-section. In this case, the conductor segments forming the plurality of turns of the coil are arranged in a matrix-like manner, which is merely exemplary, and the number of turns is also exemplary (in this case, eight). Alternatively, other configurations already proposed in the art may be used. Regarding the coil insulation 2, embodiments known in the art, such as a molded configuration and / or the use of strong adhesive tape, may also be employed.

[0029] exist Figure 1 In FIG, a substantially racetrack-like shape is shown as the geometry. The coil geometry comprises two parallel straight sections 4 connected at the longitudinal ends 5 by a first bend 6, which in this case has a constant bend radius and provides a full bend angle of 180°. In other conceivable configurations, at each longitudinal end 5, two first bends 6 with a bend angle of 90° connected by an additional straight section may be employed, and so on. The minimum bend radius of the first bend 6 is 25 to 35 mm, so that the stator winding arrangement 1 can be used in compact environments with strict geometrical constraints and requirements. See FIG. Figure 2 The inter-turn insulation 7 is designed such that, despite these bending radii, no cracks and / or wrinkles occur during the manufacture of the stator winding arrangement 1, in particular during the bending of the conductors 3 to form the turns and thus the coils (coil formation), or during use in the stator. Furthermore, improved thermal and insulating properties are provided compared to known solutions using polyimide materials. In the embodiment shown here, the inter-turn insulation 3 comprises at least one layer of mica insulating tape.

[0030] It should be noted that for simplicity the connections and contacts of the coils are not shown.

[0031] Figure 3 A specific example of a three-mica layer interturn insulation 7 on an electrical conductor 3 is shown. A pure PET tape 29 is applied directly to the conductor 3 and forms the basis. In this case, a PET-mica tape is used as the mica insulation tape 8. The mica insulation tape 8 comprises a mica sublayer 9 backed by a PET sublayer 10. Its thickness can be, for example, 0.1 to 0.5 mm.

[0032] As can be seen, in the first mica layer 11, the mica sub-layer 9 contacts the pure PET tape 29. The PET sub-layer 10 is the outer layer and is protected between the PET materials 29, 10. In all other layers 12, 13, the mica insulating tape 8 is likewise wrapped around the conductor 3 in the same orientation so that each mica sub-layer 9 contacts the PET sub-layer 10 of the inner layer 11, 12. Thus, the mica is always placed between the PET and the PET sub-layer 10 forms the outermost boundary. This reduces the mechanical stress between the layers 11, 12, 13 and prevents damage during manufacturing and during use. By displacing the mica insulating tape 8 in a staggered manner (e.g., a single strip is displaced by half the width, as shown in FIG. 2 ), the conductor 3 is protected by the PET sub-layer 10. Figure 3 The mica insulating tape 8, wrapped in different layers 11, 12, 13 (shown in FIG), provides further stability and robustness as well as resistance to mechanical stress.

[0033] The pure PET tape 29 and preferably the PET sublayer 10 are preferably solid. They do not include a textile structure or otherwise accept resin or similar materials, such as glue. For example, if VPI is applied later, only the mica sublayer 9 will accept resin.

[0034] Since the inter-turn insulation 7 has the same layer structure along its entire length, the same material (here, PET) is also in contact between adjacent sections of conductor 3 forming a turn, resulting in greater resilience with respect to mechanical stresses. The PET sublayer 10 forming the outer boundary improves mechanical protection. Cracks and wrinkles are reduced.

[0035] When used in generators, Figure 1 The straight section 4 of the coil is placed, for example, in particular adjacent to a stator tooth in a recess of the stator. The longitudinal end 5 forms a coil overhang section. Figure 1 In a first embodiment, the first bend 6 of the longitudinal end portion 5 extends in the same plane as the straight section 4. However, due to certain requirements and geometrical limitations, in particular in the case of stator teeth in which straight sections 4 of different phases are positioned alternately, a modified embodiment comprising a second bend out of the plane of the straight sections 4 may be advantageous.

[0036] Figure 4 A detail of the longitudinal end portion 5 of a modified second embodiment of the stator winding arrangement 1 according to the present invention is shown. In this embodiment, the longitudinal end portion 5 is bent out of a schematically indicated plane 15 in which the straight section 4 extends, via a second bend 14, so that the first bend 6 lies in an inclined plane 16. For both the first bend 6 and the second bend 14, the minimum bend radius lies in the range of 25 mm to 35 mm. Consequently, also with respect to the second bend 14, the interturn insulation 7 can withstand the corresponding mechanical stresses.

[0037] Figure 5The third embodiment shown in the corresponding detailed view in FIG. 1 shows that the second bent portion 14 can also achieve a bending angle of 90°, so that the inclined plane 16 is perpendicular to the plane 15 .

[0038] Bending the longitudinal ends 5 out of the plane 15 in which the straight sections 4 extend allows, for example, the passage of other coil / stator winding arrangements 1 having staggered straight sections 4 . Figure 6 A stator winding 17 is shown consisting of a plurality of groups of stator winding arrangements 1, wherein each such group comprises three stator winding arrangements 1, one for each of the three phases. Each group of three stator winding arrangements 1 mounted to the stator can be associated with a tooth structure, wherein the straight sections 4 of the three coils in the group follow one another in a staggered manner. Figure 7 In the detailed view of , it can be seen that in the coil overhang area 18, the bending angle of the second bend 14 of two stator winding arrangements 1 in a group of three stator winding arrangements 1 has been selected so that it is possible to pass through the corresponding other stator winding arrangements 1 in the group to connect the straight sections 4 positioned in a staggered manner.

[0039] Figure 8 A partial view of a wind turbine 19 according to the invention is shown. The wind turbine 19 comprises blades 20 mounted to a rotor hub 21 which is located at a nacelle 22 which is supported on a tower 23. The wind turbine 19 is a direct drive wind turbine in which a rotor 24 of a wind turbine generator 25 according to the invention is mounted directly to the hub 21. The rotor 24 is rotatably mounted around a stator 26 of the generator 25 by bearings 27. The rotor 24 comprises at least one permanent magnet 28. For simplicity, the stator windings 17 of the respective segments of the stator 26 are only schematically indicated. That is, for each stator segment of the stator 26, a winding 17 is provided as shown. Figure 6 The stator winding is shown in .

[0040] While the present invention has been described in detail with reference to the preferred embodiments, the present invention is not limited to the disclosed examples, and those skilled in the art will be able to devise other variations based on the disclosed examples without departing from the scope of the present invention.

[0041] Regardless of grammatical usage of the term, individuals with masculine, feminine, or other gender identities are included within the term.

Claims

1. A stator winding arrangement (1) for a wind turbine generator (25), comprising at least one electrical conductor (3) forming turns of at least one coil and an inter-turn insulation (7) extending around the conductor (3), the coil extending in a geometric shape with at least one bend (6, 14), characterized in that The minimum bending radius of each bend (6, 14) is in the range of 25 to 35 mm, and the inter-turn insulation (7) comprises at least one layer (11, 12, 13) of mica insulation tape (8) wound around the conductor (3) at least at the at least one bend (6, 14).

2. The stator winding arrangement according to claim 1, characterized in that The mica insulating tape (8) comprises a mica sublayer (9) which is backed on one side by a thinner PET sublayer (10).

3. The stator winding arrangement according to claim 2, characterized in that The inter-turn insulation (7) comprises an inner pure PET tape (29) and multiple layers, in particular two to four layers (11, 12, 13) of the mica insulation tape (8), wherein the different layers (11, 12, 13) are stacked so that each mica sub-layer (9) is positioned between the PET material.

4. The stator winding arrangement according to claim 2 or 3, characterized in that The PET material has a solid nonwoven structure.

5. Stator winding arrangement according to one of the preceding claims, characterized in that The inter-turn insulation (7) comprises multiple layers, in particular two to four layers (11, 12, 13) of the mica insulating tape (8), wherein along the conductor (3), the boundaries between different adjacent sections of the mica insulating tape (8) in the layers (11, 12, 13) are staggered.

6. Stator winding arrangement according to one of the preceding claims, characterized in that The thickness of the mica insulating tape (8) is 0.1 to 0.5 mm.

7. Stator winding arrangement according to one of the preceding claims, characterized in that The geometric shape is a longitudinal shape comprising two longitudinal straight sections (4), wherein at least one first bend (6) of the at least one bend connects the straight sections (4) at at least one longitudinal end (5).

8. The stator winding arrangement according to claim 6, characterized in that The geometric shape is at least substantially a racetrack shape, and / or at least one first bend (6) comprises a bend angle of the conductor (3) of at least substantially 180°.

9. The stator winding arrangement according to claim 6 or 7, characterized in that The second bend (14) of the more than one bends (6, 14) bends the longitudinal end (5) out of the plane (15) in which the straight section (4) extends, in particular at a predetermined bend angle.

10. Stator winding arrangement according to one of the preceding claims, characterized in that The conductor (3) comprises copper and / or is a stranded wire and / or has an at least substantially rectangular or circular cross-sectional shape.

11. Wind turbine generator (25) comprising a stator (26) and a rotor (24), the stator (26) having a plurality of stator winding arrangements (1) according to one of the preceding claims.

12. The wind turbine generator according to claim 10, wherein: The coils of the stator winding arrangement (1) each comprise a straight section (4) extending in parallel in a recess of the stator (26) and a first bend (6) in the coil overhang region (18).

13. The wind turbine generator according to claim 11, wherein: A plurality of stator winding arrangements (1) are provided at one of a plurality of tooth structures for different phases, wherein the straight sections (4) of the stator winding arrangements (1) extend in parallel, wherein at least one of the stator winding arrangements (1) of each tooth structure is bent, thereby forming a second bend (14) in the coil overhang region (18) at a bending angle away from a plane (15) extending from the straight section (4) to pass through the stator winding arrangement (1) of another phase.

14. A wind turbine (19) comprising a wind turbine generator (25) according to any one of claims 10 to 12.

15. A method for producing a stator winding arrangement (1) for a wind turbine generator (25), comprising the steps of: - provide electrical conductors (3), - wrapping at least one layer (11, 12, 13) of mica insulating tape (8) around the conductor (3) as an inter-turn insulation (7), and - bending the conductor (3) into a coil having a plurality of turns and a geometric shape with at least one bend (6, 14), wherein the minimum bend radius of each bend (6, 14) is in the range of 25 to 35 mm.

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