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The present disclosure is related to a cooling profile for a transformer and a corresponding transformer.
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Transformers are used to transfer an output voltage of an electrical circuit to an input voltage for another electrical circuit. Transformers comprise an active part including windings which are closed in a tank or housing. In general, it is a challenge to increase the efficiency of a transformer.
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Embodiments of the present disclosure relate to a transformer enclosure and a transformer that enable reliable operation and contribute to an improved efficiency.
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According to an embodiment, a cooling profile for a transformer with an elongated shape and a predetermined length along a longitudinal axis comprises a first contact portion and a second contact portion. The first contact portion is configured to be coupled to a first winding, e.g. an inner winding, of the transformer. The second contact portion configured to be coupled to a second winding, e.g. an outer winding, of the transformer. The cooling profile further comprises a middle web connecting the first and the second contact portion along a transverse axis transverse to the longitudinal axis. The cooling profile further comprises a fin structure including at least one protrusion arranged on the middle web between the first contact portion and the second contact portion along the transverse axis such that the fin structure, the first contact portion and the second contact portion form a plurality of colling channels opened along the longitudinal axis.
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Due to the described configuration of the cooling profile with multiple cooling channels opened to the outside, a transformer is feasible that enables reliable operation and an enhancement in efficiency due to an improved heat dissipation. The design of the cooling profile allows for an improved air-ventilation during operation of the corresponding transformer. The at least one fin protrusion partly divides the space between the first and second contact portion and hence contributes to an enlarged surface area and in interaction with the first and the second contact portion partly limits two opened cooling channels on opposite sides of the protrusion.
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The cooling profile is configured to be arranged between two windings and the first winding may have a smaller radius than the second winding with respect to a radial extension direction perpendicular to the longitudinal axis. Therefore, the first winding can also be referred to as inner winding and the second winding may surround the first, inner winding and can also be referred to as outer winding. Between these windings there is a predetermined intermediate space and the cooling profile or preferably a plurality of the cooling profile is arranged in the intermediate space between the inner winding and outer winding.
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The cooling profile is in contact on both sides, on the one hand with the first, inner winding and on the other hand with the second, outer winding, for stability and also for heat dissipation. The heat dissipation through the fin structure is improved significantly. There can also be a third or more windings surrounding the second winding which would then represent a middle or an inner winding. The first winding would then realize the innermost winding. Between two adjacent windings there can be arranged a plurality of the cooling profiles as described. The windings each comprise a wounded conductor and an insulator and are parts of the same low voltage winding, for example. Adjacent windings are connected.
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The longitudinal axis may also represent an upright or vertical axis with regard to an operational state of the transformer. Accordingly, the upright longitudinal axis is substantially perpendicular to lateral or radial directions and the transverse axis which can be assigned to horizontal directions.
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According to an embodiment of the cooling profile and with respect to a cross-section transverse to the longitudinal axis, the first contact portion and/or the second contact portion is plate-shaped predominantly extending transversely to the middle web. In view of the cross section, the cooling profile may comprise an H-shape with one or more fin protrusions inbetween on one side and/or both sides of the H-shape.
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According to a further embodiment of the cooling profile and with respect to a cross-section transverse to the longitudinal axis, the at least one protrusion of the fin structure is rod-shaped or plate-shaped predominantly extending transversely to the middle web. In view of the aforementioned H-shape, the one or more protrusions of the fin structure can nearly have the same extension and/or shape as the first and/or the second contact portion.
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According to a further embodiment of the cooling profile and with respect to a cross-section transverse to the longitudinal axis, the at least one protrusion of the fin structure comprises a wave-shaped surface structure. Such a surface structure can further contribute to an enlarged surface area for cooling and to a partially guided movement of the flowing cooling. Alternatively or additionally, the first contact portion and/or the second contact portion comprises a wave-shaped surface structure with respect to a cross-section transverse to the longitudinal axis.
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According to a further embodiment of the cooling profile, the at least one protrusion of the fin structure is arranged equidistant from the first and the second contact portion forming corresponding cooling channels of approximately the same width. Alternatively, a width of one or more cooling channels can be formed differently to provide a desired streaming condition for cooling air.
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According to a further embodiment of the cooling profile and with respect to a cross-section transverse to the longitudinal axis, the cooling profile comprises a predetermined height and/or width formed in coordination with a predetermined intermediate space between the intended first and second winding of the transformer. The height may represent the extension in radial direction so transverse to the longitudinal axis. Accordingly, the height preferably matches the radial distance between first, inner winding and the second, outer winding so that the cooling profile can be securely and reliably arranged in between contacting both windings. For example, the distance between an outer surface of the inner winding and an inner surface of the outer winding is 4 to 8 mm. Accordingly, the height of the cooling profile can be given with a value of 4 to 8 mm. The width may represent the extension in circumferential direction so also transverse to the longitudinal axis and the radial direction.
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According to a further embodiment of the cooling profile, the fin structure comprises four protrusions, two on each of the opposite sides of the middle web, forming in interaction with the first contact portion and the second contact portion six colling channels opened along the longitudinal axis.
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According to a further embodiment of the cooling profile, the first and/or the second contact portion comprises a respective contact surface which is formed in coordination with an associated contact surface of the first or the second winding, respectively. For example, the windings are usually formed with a ring- or hollow-cylindrical shape surrounding the longitudinal axis as their centre axis. Accordingly, the contact surfaces of the windings are curved and it can be beneficial to form the contact surface of the first and/or the second contact portion with a corresponding curved shape. The contact surface can therefore follow the shape of the inner surface of the outer winding and/or the outer surface of the inner winding. Such a matching contact with the same shape can contribute to a secure hold and high stability of the cooling profile in the intermediate space between the windings.
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According to an embodiment, a transformer comprises a first winding and a second winding for transforming voltage, and at least one embodiment of the described cooling profile. The first winding and the second winding are arranged with a predetermined intermediate space in between, and the at least one cooling profile is arranged in the intermediate space and contacts the first and the second winding by means of its first and second contact portion, respectively. Due to the fact that the transformer comprises an embodiment of the cooling profile, the described features and characteristics of the cooling profile are also disclosed for the transformer and vice versa. The transformer can be realized as a dry type transformer.
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It is a finding of the present disclosure that conventional designs of a transformer may include inefficient air cooling. Consequently, air cooling of windings, e.g. in dry type transformers, is an ongoing challenge.
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By use of the described configuration with the cooling profile a beneficial air ventilation can flow through between the windings and the multiple air cooling channels. It is not necessary to provide an oversized transformer design or a complex cooling concept and the manufacturing costs can be kept low. The described cooling profile can also be retrofitted to existing transformers with little effort and at low cost. Accordingly, the described cooling profile enables improvements in cooling and allows for a compact design of a transformer complying with the last standards. The described cooling profile and the corresponding transformer also contribute to reduce a carbon foot print.
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The cooling profile with its air cooling channels comprise a specific shape with one or more fins that increases a surface and improves the heat dissipation due to increased convection. The cooling profile is expected to increase the effect of air forced cooling and maybe also the behaviour of natural cooling too, because of reducing a temperature inside the winding during operation. The desired shape with the finned and optionally waved profile can increase the surface available to contact with air up to 50 or 60%. Due to the increased surface for air contact, the cooling profile can be manufactured relatively thin to reduce material costs.
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The cooling profile can be manufactured relatively cheap by means of extruded bars, a complex shape is not required and extra costs can be kept low. For this purpose, the cooling profile can be formed by means of an aluminium extruder with presetting the desired profile in terms of a matrix. In this context, it is expected to significantly reduce hot spot temperatures and an average temperature inside the transformer or the windings, and to increase an insulation life at the end.
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Exemplary embodiments are explained in the following with the aid of schematic drawings and reference numbers. The figures show:
- Figures 1-14
- embodiments of a cooling profile for a transformer in different views.
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The accompanying figures are included to provide a further understanding. It is to be understood that the embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale. Identical reference numbers designate elements or components with identical functions. In so far as elements or components correspond to one another in terms of their function in different figures, the description thereof is not repeated for each of the following figures. For the sake of clarity elements might not appear with corresponding reference symbols in all figures, possibly.
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The figures 1 to 14 show embodiments of a cooling profile 10 for a transformer in different views. Figure 1 illustrates an embodiment of the cooling profile 10 in a perspective view. The cooling profile 10 comprises an elongated shape with a predetermined length L along a longitudinal axis A (see Fig. 2). The cooling profile 10 comprises a first contact portion that is configured to be coupled to a first winding 1 of the transformer (see also Figs. 7, 8 and 14). The cooling profile 10 further comprises a second contact portion 12 that is configured to be coupled to a second winding 2 of the transformer (see also Figs. 7, 8 and 14). Due to the concentric arrangement of the windings 1 and 2 surrounding the longitudinal axis A, the first winding 1 can also be referred to as the inner winding and the second winding 2 can also be referred to as the outer winding.
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The cooling profile 10 further comprises a middle web 18 that connects the first contact portion 11 and the second contact portion 12 along a transverse axis B transverse to the longitudinal axis A (see, for example, Figs. 3, 4 and 9).
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The cooling profile 10 further comprises a fin structure 20 that comprises one or more protrusion 21 arranged on the middle web 18 between the first contact portion 11 and the second contact portion 12 along the transverse axis B. The fin structure 20, the first contact portion 11 and the second contact portion 12 form or limit a plurality of cooling channels 17 which are opened outwardly along the longitudinal axis A.
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The described and illustrated configurations of the cooling profile 10 with cooling channels 17 opened to the outside allow for a transformer with reliable operation and an enhancement in efficiency due to an improved heat dissipation. The design of the cooling profile 10 enables an improved air-ventilation during operation of the transformer. The fin structure 20 partly divides the space between the first and second contact portion 11, 12 and hence contributes to an enlarged surface area and in interaction with the first and the second contact portion 11, 12 partly limits the opened cooling channels 17.
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The cooling profile 10 is designed to be arranged between the windings 1, 2. The windings 1, 2 are configured for transforming voltage and are arranged with a predetermined intermediate space 4 inbetween (see Figs. 6-8 and 14). A plurality of cooling profiles 10, e.g. 10, 20 or 50 cooling profiles 10, is arranged in the intermediate space 4 such that the first contact portion 11 contacts the first, inner winding 1 and the second contact portion 12 contacts the second, outer winding 2 with a respective contact surface 13, 14, respectively.
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In some embodiments, the contact surfaces 13 and/or 14 of the first and the second contact portion 11, 12 are formed in coordination with an associated contact surface of the first and the second winding 1, 2, respectively. Therefore, the contact surfaces 13, 14 can be formed to follow a shape of the windings 1, 2. According to the cylindrical windings 1, 2, the contact surfaces 13, 14 of the first and the second contact portion 11, 12 can be formed with a curved shape in coordination with a ring- or hollow-cylindrical shape of the first winding 1 and the second winding 2 (see Figs. 11-14). Preferably, the cooling profile 10 comprises a given waveshape at its outer surface that is in contact with air. With respect to a cross-section transverse to the longitudinal axis A (as shown in the Figs. 3 and 6), the one or more protrusion 21 of the fin structure 20 can comprise a wave-shaped surface structure 22. Alternatively or additionally, the first and/or the second contact portion 11, 12 can comprise a wave-shaped surface structure 22 (see also Figs. 1 and 4). Alternatively or additionally, the middle web 18 can comprise a wave-shaped surface structure 22. The wave-shaped surface structure 22 contributes to a further enlarged surface area for cooling and to a partially guided movement of the flowing cooling air.
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The figures 7 and 8 illustrate an embodiment of the windings 1 and 2 with a plurality of cooling profiles 10 arranged in the intermediate space 4. The figure 7 shows a perspective view and the figure 8 shows a corresponding top view. The windings 1 and 2 are coupled to a holding structure 3 to support them and/or to couple them to a tank or housing of the transformer.
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The figures further illustrate that the first contact portion 11, the second contact portion 12 and/or the one or more protrusions 21 of the fin structure 20 can comprise different sizes and/or shapes with respect to the shown cross-sections (see Figs. 9-13). Alternatively, the first contact portion 11, the second contact portion 12 and/or the one or more protrusions 21 of the fin structure 20 can substantially comprise the same size and/or shape as shown in the Figs. 1, 3-5 and 13.
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The embodiment shown in the figures 1 to 14 as stated represent an exemplary embodiment of the improved transformer with cooling profiles 10. Therefore, it does not constitute all embodiments. Actual arrangements may vary from the embodiment shown in the figures.
Reference Signs
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- 1
- first winding / inner winding
- 2
- second winding / outer winding
- 3
- holding structure
- 4
- intermediate space
- 10
- cooling profile
- 11
- first contact portion / inner contact portion
- 12
- second contact portion / outer contact portion
- 13
- contact surface of the first contact portion
- 14
- contact surface of the second contact portion
- 15
- protrusion of the first contact portion
- 16
- protrusion of the second contact portion
- 17
- cooling channel
- 18
- middle web
- 20
- fin structure
- 21
- protrusion of the fin structure
- 22
- wave-shaped surface structure
- A
- longitudinal axis of the cooling profile and the windings
- B
- transverse axis of the cooling profile
- H
- height of the cooling profile
- W
- width of the cooling profile
- L
- length of the cooling profile