Transformer enclosure and transformer

Abstract

A transformer enclosure (1) for a transformer compr ises: - a wall structure (6) with one or more lateral si de walls configured to laterally surround the transfor mer with respect to an upright longitudinal axis (L) of the transformer enclosure (1), - top structure (3) coupled to the wall structure (6) and configured to cover a top of the transformer wi th respect to the longitudinal axis (L), and - a cover structure (2) forming a cover above the top structure (3) on a side opposite the wall structure (6) with respect to the longitudinal axis (L), wherein the c over structure (2) is coupled to and spaced apart from t he top structure (3) with a predetermined distance in betw een such that the cover structure (2) and the top structure (3) form a double panel structure with an air channel (12) in between for air ventilation.

Description

[0001] P2024, 1126 WO N / P240142WO01 January 23, 2026

[0002] Description

[0003] TRANSFORMER ENCLOSURE AND TRANSFORMER

[0004] The present disclosure is related to a transformer enclosure and a corresponding transformer.

[0005] 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.

[0006] Embodiments of the present disclosure relate to a transformer enclosure and a transformer that enable reliable operation and contribute to an improved efficiency.

[0007] According to an embodiment, a transformer enclosure for a transformer comprises a wall structure, a top structure, and a cover structure. The wall structure includes one or more lateral side walls configured to laterally surround the transformer with respect to an upright longitudinal axis of the transformer enclosure. The top structure is coupled to the wall structure and is configured to cover a top of the transformer with respect to the longitudinal axis. The cover structure forms a cover above the top structure on a side opposite the wall structure with respect to the longitudinal axis. The cover structure is coupled to and spaced apart from the top structure with a predetermined distance in between such that the cover structure and the top structure form a double panel structure with an air channel in between for air ventilation. The cover structure is coupled to the topP2024, 1126 WO N / P240142WO01 January 23, 2026

[0008] 2

[0009] structure such that the predetermined distance has a value in a range of 2 cm to 10 cm.

[0010] Due to the described configuration with the double panel structure a transformer is feasible that enables reliable operation and an enhancement in efficiency due to an improved heat dissipation. The interaction of the top structure and the cover structure above allows for an air- ventilated double- skin roof for a dry- type transformer enclosure. The cover structure is arranged above the top structure which in turn is arranged above the one or more side walls of the transformer enclosure along upright longitudinal axis. With regard to an operational state of the transformer, the upright longitudinal axis substantially represents a vertical axis which is perpendicular to lateral directions which can follow respective horizontal axis.

[0011] It is a finding of the present disclosure that conventional designs of a transformer and its housing have a big exposition to the sun and require oversized transformer designs and general dimensions or complex cooling concepts to reduce temperature inside the housing. For example, this applies to conventional photovoltaic solar plants and its dry- type transformers.

[0012] By use of the described configuration with the double panel structure a beneficial air ventilation can flow through the the cover structure and the top structure and can dissipate heat generated during operation of the transformer. 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 concept can also be retrofitted to existing transformers with little effort and at low cost.P2024, 1126 WO N / P240142WO01 January 23, 2026

[0013] Alternatively or additionally to the double panel structure at the top, the transformer enclosure can comprise a double panel structure with an air channel in between for air ventilation at the side wall structure. Accordingly, the side wall structure can be covered by a cover structure which forms a cover next to the side wall structure on a side opposite the wall structure with respect to a lateral direction perpendicular to the upright longitudinal axis. Such an alternative or additional cover structure is coupled to and spaced apart from the side structure with a predetermined distance to form an air channel.

[0014] According to an embodiment of the transformer enclosure, the cover structure is formed in coordination with the top structure and covers the top structure completely with respect to lateral directions perpendicular to the upright longitudinal axis. Consequently, the cover structure can cover the top structure partly or in sections or completely. Moreover, cover structure can be configured to cover the top structure completely and to extend laterally beyond the top structure at one or more sides.

[0015] According to a further embodiment, the transformer enclosure comprises a support structure coupled to the cover structure and the top structure configured to set the predetermined distance between the cover structure and the top structure. For example, the support structure comprises one or more spacer elements arranged between the cover structure and the top structure. Alternatively or additionally, the support structure can comprise an external retaining structure to hold the cover structure in its predetermined position.P2024, 1126 WO N / P240142WO01 January 23, 2026

[0016] According to a further embodiment of the transformer enclosure, the support structure comprises one or more openings which are formed in the cover structure and / or the top structure configured in coordination with the one or more spacer elements and / or the external retaining structure. Such openings can form recesses to insert a bolt, a screw and / or a pin element. For example, the spacer elements are formed as posts or columns and comprise one or more threaded recesses, e.g. at opposite sides, such that it can be fixed to a cover element of the cover structure on one side and to a top element of the top structure on the opposite side by means of respective screws extending through the cover element or the top element into the spacer element, respectively.

[0017] The cover structure is coupled to the top structure such that the predetermined distance has a value in a range of 2 cm to 10 cm. Preferably, the distance has a value in a range of 4 cm to 8 cm, e.g. a predetermined distance with a value of 6 cm, to enable a beneficially guided streaming conditions of the air flow inside the air channel.

[0018] According to a further embodiment of the transformer enclosure, the cover structure is coupled to the top structure such that the predetermined distance is set predominantly equidistantly. Alternatively, the distance between the cover structure and the top structure can follow a predefined course to affect the air flow in the air channel.

[0019] The air channel of the transformer enclosure can be formed to provide one or more strip- or rod- shaped ventilation passages. For example, such located and relatively narrow channels can be directed above specific points of interestsP2024, 1126 WO N / P240142WO01 January 23, 2026

[0020] 5

[0021] for dissipating heat. Alternatively, the air channel of the transformer enclosure is formed to provide plate- shaped ventilation area to enable relatively large- scale cooling and heat dissipation. The aforementioned distance can be set to affect the flow characteristics inside the one or more air channels, e.g. to have a wider entrance and a narrower exit and thus accelerating the cooling air flowing inside the air channel.

[0022] According to a further embodiment of the transformer enclosure, the cover structure and the top structure are formed in coordination with each other and both comprise one or more plate shaped elements. The plate shaped elements of the cover structure are coupled to predominantly reproduce a shape of the coupled plate shaped elements of the top structure. Such a configuration for example allows for a substantially equidistant air channel. Alternatively, the cover structure can be made from one piece.

[0023] According to a further embodiment of the transformer enclosure, the cover structure and / or the top structure are configured to form a tilted air channel with respect to a lateral direction perpendicular to the upright longitudinal axis. Such a configuration can provide beneficial air flow conditions and additionally allows to withstand environmental influences such as rain or snow which can run off along the slope.

[0024] According to a further embodiment of the transformer enclosure, the cover structure extends beyond the top structure laterally on one side at least which is configured to form an inlet and / or outlet for air ventilation. Such a configuration can also provide beneficial air flow conditionsP2024, 1126 WO N / P240142WO01 January 23, 2026

[0025] 6

[0026] due to the entrance or inlet and the exit or outlet. For example, a corresponding transformer is placed at a position which has a preferred direction or orientation with regard to air flows. Such a preferred direction or orientation can be affected by a neighboured wood or fence or wall, for example. Accordingly, it might be beneficial to implement an inlet in the direction which is not blocked by structures arranged close to the transformer.

[0027] Alternatively, the cover structure can be configured so that it is arranged at the same distance above the top structure, so that an inlet and outlet for air flow are formed all around it. Accordingly, the inlet and outlet can be exchanged and may represent the same free space between the cover structure and the top structure.

[0028] According to a further embodiment, the transformer enclosure comprises a wall cover structure with one or more lateral cover walls surrounding the one or more lateral sidewalls of the wall structure with respect to the upright longitudinal axis. The wall cover structure is coupled to and spaced apart from the wall structure with a predetermined distance in between such that the wall structure and the cover wall structure form a double panel structure with an air channel in between for air ventilation.

[0029] According to a further embodiment of the transformer enclosure, the cover structure and the top structure are formed predominantly full-surface or recess-free. Recesses may affect the air flow conditions and consequently, a full -surface or recess - free plate- shaped cover structure and top structure may provide beneficial air flow conditions.P2024, 1126 WO N / P240142WO01 January 23, 2026

[0030] 7

[0031] According to an embodiment, a transformer comprises electric components for transforming voltage, and an embodiment of the described transformer enclosure that houses the electric components. Due to the fact that the transformer comprises an embodiment of the transformer enclosure, the described features and characteristics of the transformer enclosure are also disclosed for the transformer and vice versa. For example, the transformer may have a height, a length and a width of 2 m or more each.

[0032] The concept of a double skin panel can be attached to the roofs and / or the walls in outdoor transformers enclosures. This allows to improve significantly the thermal behaviour of the transformer enclosure reducing solar radiation with an air ventilated gap between sloped panels and reducing a temperature inside the enclosure between 2 and 6 degrees with a clear and cheap structure. This can further contribute to a significant improvement in efficiency of the transformer.

[0033] The cover structure above the top structure merely requires less than 0.7% of total costs of the transformer. There is no need for an expensive solution such as oversizing the transformer to absorb the thermal contribution of the sun radiation or an insulate roof or increasing the housing height or providing complex cooling concepts. Preferably, the cover structure has a small thickness and is designed with low weight and allows ambient air to move freely between the panels of the cover structure and the top structure. The cover structure can be made of the same material as the further enclosure components, e.g. galvanized steel. The improved thermal dissipation by means of convection and avoiding heat panel radiator effect enables to reduce theP2024, 1126 WO N / P240142WO01 January 23, 2026

[0034] losses and the average temperature at least. A temperature drop inside the enclosure between 2 °C and 6 °C is feasible.

[0035] The described double panel structure concept can be adopted to all the ranges of enclosures manufactured for transformers. The described concept allows to design customized dimensions of double- skin roof panels for each enclosure that should be protected. The cover structure is designed to shade a main roof or top of the transformer and create an air gap that facilitates natural convection at the same time that mitigates the radiant barrier effect with the shadow. This allows for efficient dissipation of heat generated between the two roofs, realized by the top structure and the cover structure. The described concept is not limited to sunniest or hottest locations because the convection factor depends on the Reynolds an Nusselt number that changes with air speed, which is not stationary and more relevant with the temperature. The effectiveness of the described concept may be more obvious during hot days due to the direct influence of temperature in Reynolds and Nusselt numbers, less viscosity. The higher the temperature, the higher the convection coefficient and better performance of the transformer can expected using the described double panel concept. A significant effect in natural cooling can be expected and due to air forced cooling, the effect will be directly related with reduce working hours in non continuous cooling systems, reducing thermal fatigue in epoxy cast coils due to softer changes of temperature and allowing optimize the size / cost of the dry type transformer.

[0036] Exemplary embodiments are explained in the following with the aid of schematic drawings and reference numbers. The figures show:P2024, 1126 WO N / P240142WO01 January 23, 2026

[0037] Figures 1 - 4 embodiments of a transformer with a transformer enclosure in different views.

[0038] 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 f igures. For the sake of clarity elements might not appear with corresponding reference symbols in all figures, possibly.

[0039] Figure 1 illustrates an embodiment of a transformer in a perspective view. The transformer comprises electric components for transforming voltage and a transformer enclosure 1 that houses the electric components. The transformer enclosure 1 comprises a wall structure 6 with six lateral side walls which laterally surround the transformer with respect to an upright longitudinal axis L. According to the figures, the upright longitudinal axis L can also be referred to as vertical.

[0040] The transformer enclosure 1 further comprises a top structure 3 that is coupled to the wall structure 6 and that covers a top of the transformer with respect to the longitudinal axis L.

[0041] The transformer enclosure 1 further comprises a cover structure 2 that forms a cover above the top structure 3 on a side opposite the wall structure 6 with respect to theP2024, 1126 WO N / P240142WO01 January 23, 2026

[0042] 10

[0043] longitudinal axis L. The cover structure 2 is coupled to and spaced apart from the top structure 3 with a predetermined distance in between such that the cover structure 2 and the top structure 3 form a double panel structure with an air channel 12 in between for air ventilation (see also Fig. 4).

[0044] Due to the described configuration with the double panel structure the transformer enables reliable with enhanced efficiency due to an improved heat dissipation that result from operation of the transformer. The cover structure 2 is arranged above the top structure 3 which in turn is arranged above the side walls of the transformer enclosure 1.

[0045] The figures 2 and 3 each show a perspective view of the top of the transformer. Figure 2 shows a view before assembling the cover structure 2 at the top structure 3. Figure 3 shows an assembled state of the top of the transformer enclosure 1.

[0046] The cover structure 2 is formed in coordination with the top structure 3 and covers the top structure 3 completely with respect to lateral directions perpendicular to the upright longitudinal axis L. The cover structure 2 and the top structure 3 are formed in coordination with each other and both comprise three plate shaped elements 21, 22, 23 or 31, 32, 33, respectively. The plate shaped elements 21, 22, 23 of the cover structure 2 are coupled to predominantly reproduce a shape of the coupled plate shaped elements 31, 32, 33 of the top structure 3. The cover structure 2 is coupled to the top structure 3 such that the predetermined distance is set predominantly equidistantly (see Fig. 4).

[0047] The transformer enclosure 1 comprises a support structure coupled to the top structure 3 that sets the predeterminedP2024, 1126 WO N / P240142WO01 January 23, 2026

[0048] 11

[0049] distance between the cover structure 2 and the top structure 3 by means of a plurality of spacer elements 5 arranged inbetween. The support structure utilizes openings 25 which are formed in the cover structure 2 which are configured in coordination with the spacer elements 5. The openings 25 can form recesses to accommodate a portion of the spacer elements 5 and / or to enable fixing the cover structure 2 to the spacer elements 5 and the top structure 3 by means of screws, for example. The spacer elements 5 can be formed such that the cover structure 2 is coupled to the top structure 3 with the predetermined distance inbetween to have a value in a range of 2 cm to 10 cm, preferably a value in a range of 4 cm to 8 cm, or a value of about 6 cm.

[0050] The support structure further comprises coupling lugs 4 which are arranged at the second top element 32 and which interact with corresponding openings 24 penetrating the second cover element 22. Such coupling lugs 4 can contribute to a reliable and secure hold of the cover structure 2 above the top structure 3.

[0051] Figure 4 shows that the cover structure 2 and the top structure 3 can be formed to provide a tilted air channel 12 along a lateral direction perpendicular to the upright longitudinal axis L. The cover structure 2 extends beyond the top structure 3 laterally configured to form an inlet 8 and an outlet 9 for air ventilation. Illustrated arrows are intended to represent sunlight 10 hitting the cover structure 2. Further illustrated arrows are intended to represent an air flow 11 inside the air channel 12 entering thought the inlet 8 and exiting through the outlet 9 depending on the environmental air flow conditions. Accordingly, with reversedP2024, 1126 WO N / P240142WO01 January 23, 2026

[0052] 12

[0053] air flow conditions in the environment the outlet 9 would form an inlet and the inlet 8 would form an outlet.

[0054] The transformer enclosure 1 further comprises a bottom structure 7 which forms the contact portion to the installation surface or ground.

[0055] The embodiment shown in the figures 1 to 4 as stated represent an exemplary embodiment of the improved transformer with its transformer enclosure 1. Therefore, it does not constitute all embodiments. Actual arrangements may vary from the embodiment shown in the figures.P2024, 1126 WO N / P240142WO01 January 23, 2026

[0056] 13

[0057] Reference signs

[0058] 1 transformer enclosure

[0059] 2 cover structure

[0060] 21 first cover element

[0061] 22 second cover element

[0062] 23 third cover element

[0063] 24 opening

[0064] 25 opening

[0065] 3 top structure

[0066] 31 first top element

[0067] 32 second top element

[0068] 33 third top element

[0069] 4 coupling lug

[0070] 5 spacer element

[0071] 6 wall structure

[0072] 7 bottom structure

[0073] 8 inlet of the air channel

[0074] 9 outlet of the air channel10 sunlight

[0075] 11 air flow

[0076] 12 air channel

[0077] L longitudinal / vertical axis

Claims

P2024, 1126 WO N / P240142WO01 January 23, 2026- 14 -Claims1. Transformer enclosure (1) for a transformer, comprising:- a wall structure (6) with one or more lateral side walls configured to laterally surround the transformer with respect to an upright longitudinal axis (L) of the transformer enclosure (1),- top structure (3 ) coupled to the wall structure (6) and configured to cover a top of the transformer with respect to the longitudinal axis (L), and- a cover structure (2) forming a cover above the top structure (3 ) on a side opposite the wall structure (6) with respect to the longitudinal axis (L), wherein the cover structure (2) is coupled to and spaced apart from the top structure (3 ) with a predetermined distance in between such that the cover structure (2) and the top structure (3 ) form a double panel structure with an air channel (12) in between for air ventilation, characterized in thatthe cover structure (2) is coupled to the top structure (3 ) such that the predetermined distance has a value in a range of 2 cm to 10 cm.

2. Transformer enclosure (1) according to claim 1, wherein the cover structure (2) is formed in coordination with the top structure (3 ) and covers the top structure (3 ) completely with respect to lateral directions perpendicular to the upright longitudinal axis (L).

3. Transformer enclosure (1) according to any of the preceding claims, comprising:a support structure coupled to the cover structure (2) and the top structure (3 ) configured to set the predeterminedP2024, 1126 WO N / P240142WO01 January 23, 2026- 15 -distance between the cover structure (2) and the top structure (3 ).

4. Transformer enclosure (1) according to claim 3, wherein the support structure comprises one or more spacer elements (5) arranged between the cover structure (2) and the top structure ( 3 ).

5. Transformer enclosure (1) according to claim 4, wherein the support structure comprises one or more openings (25) which are formed in the cover structure (2) and / or the top structure (3 ) configured in coordination with the one or more spacer elements (5).

6. Transformer enclosure (1) according to any of the preceding claims, wherein the cover structure (2) is coupled to the top structure (3 ) such that the predetermined distance has a value 6 cm.

7. Transformer enclosure (1) according to any of the preceding claims, wherein the cover structure (2) is coupled to the top structure (3 ) such that the predetermined distance is set predominantly equidistantly.

8. Transformer enclosure (1) according to any of the preceding claims, wherein the cover structure (2) and the top structure (3 ) are formed in coordination with each other and both comprise one or more plate shaped elements (21, 22, 23, 31, 32, 33 ), wherein the plate shaped elements (21, 22, 23 ) of the cover structure (2) are coupled to predominantly reproduce a shape of the coupled plate shaped elements (31, 32, 33 ) of the top structure (3 ).P2024, 1126 WO N / P240142WO01 January 23, 2026- 16 -9. Transformer enclosure (1) according to any of the preceding claims, wherein the cover structure (2) and / or the top structure (3 ) are configured to form a tilted air channel (12) with respect to a lateral direction perpendicular to the upright longitudinal axis (L).

10. Transformer enclosure (1) according to any of the preceding claims, wherein the cover structure (2) extends beyond the top structure (3 ) laterally on one side at least which is configured to form an inlet (8) and / or outlet (9 ) for air ventilation.

11. Transformer enclosure (1) according to any of the preceding claims, comprising:a wall cover structure with one or more lateral cover walls surrounding the one or more lateral sidewalls of the wall structure (6) with respect to the upright longitudinal axis (L), wherein the wall cover structure is coupled to and spaced apart from the wall structure (6) with a predetermined distance in between such that the wall structure (6 ) and the cover wall structure form a double panel structure with an air channel in between for air ventilation.

12. Transformer enclosure (1) according to any of the preceding claims, wherein the cover structure (2) and the top structure (3 ) are formed predominantly full-surface or recess-free.

13. Transformer, comprising:- electric components for transforming voltage, and - a transformer enclosure (1) according to any of the preceding claims that houses the electric components.

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