Transformer device

Abstract

The present disclosure relates to a transformer device (100), which includes a transformer (10) including at least one phase winding (12). The phase winding (12) has coil turns around a coil axis (c). The transformer device (100) also includes a transformer box (20) having a wall (22) forming a housing, in which the transformer (10) is arranged. The housing contains an incompressible medium, in which the transformer (10) is immersed. A partition (30) is arranged in the transformer box (20), between the wall (22) of the transformer box (20) and the at least one phase winding (12) of the transformer (10). The partition (30) has an inner surface facing the transformer and an outer surface facing the wall. The partition (30) is also arranged spaced apart from the at least one phase winding (12) of the transformer (10). The transformer tank (20) has a first wall (22') adjacent to a first end of the transformer (10) and extending transversely to a first axis (z), and an opposite second wall (22") adjacent to a second end of the transformer (10) and extending transversely to the first axis (z). The partition (30) has at least one first portion (32') and at least one second portion (32") both extending transversely to the first axis (z), wherein the at least one first portion (32') is arranged between the first end of the transformer (10) and the first wall (22') of the transformer tank (22), and the at least one second portion (32") is arranged between the second end of the transformer (10) and the second wall (22") of the transformer tank (20).

Description

Technical Field

[0001] The present disclosure relates to a transformer device for reducing load noise. Background Art

[0002] Transformers must comply with various noise level requirements. Transformers immersed in electrical insulating oil in the transformer tank vibrate during operation. The vibrations are transferred from the transformer windings to the tank walls via the oil, which causes significant vibration displacements of the tank walls and thus noise. Three main noise sources can be identified in transformers: no-load noise or core noise due to magnetostriction, load noise due to electromagnetic forces in the windings, and noise from auxiliary equipment such as fans and pumps used in the cooling system. Of the three, load noise contributes significantly to the total noise, especially for large units.

[0003] Today’s noise reduction solutions are inefficient, costly, and are applied far from the source and main transmission path of the load noise. Traditional solutions are often bulky and impractical, such as sound panels and damping layers attached to the outside of the box wall. Sand-filled box structural elements are another low-noise solution, but are mainly used for core noise and have limited impact on load noise. Due to the complex vibration / radiation characteristics of the transformer box of the enclosed transformer, traditional solutions are difficult to optimize and standardize for off-the-shelf daily design work. Sometimes, there are also significant differences between units.

[0004] According to its abstract, WO0101425 relates to a sound insulation device for a fixed induction motor, the fixed induction motor having an active part, an insulating fluid surrounding the active part, and a box enclosing the insulating fluid. The sound absorbing device comprises a gas-filled cavity and an elastic membrane surrounding the gas-filled cavity, thereby obtaining a highly compressible sound insulation device. In the induction motor, the device is arranged between the active part and the box of the induction motor and is spaced apart from the interior of the box. The sound insulation device preferably has an extension in one plane, whereby the device has a membrane part facing the active part and a membrane part facing the box. Preferably, at least one membrane part has at least one corrugated area, and the spacing membrane is arranged in the cavity, contacting the membrane part at at least two points.

[0005] According to its abstract, JPH10106854 relates to a fixed induction electrical equipment capable of reducing noise even when the equipment is compactly constructed. A resonance type muffler having a partially formed internal cavity opening is provided on the inner surface of a box. Since the muffler is set at a frequency that resonates with the frequency of noise generated in the box, the muffler can reduce the noise in the box by resonating with the noise frequency. Therefore, the noise radiated from the box to the outside can be reduced.

[0006] According to its abstract, CN201732653 relates to a soundproof oil tank structure of a transformer, including an oil tank body, wherein the inner wall of the oil tank body is provided with a composite damping steel plate; when the inner wall of the oil tank body is provided with a magnetic shield, two layers of composite damping steel plates are provided on the inner and outer sides of the magnetic shield, respectively, and are pressed by the clamping plates of the magnetic shield; when the inner wall of the oil tank body is not provided with a magnetic shield, the composite damping steel plate is fixed to the inner wall of the oil tank body through a mounting seat. By arranging the composite damping steel plate on the inner wall of the oil tank body of the transformer, the noise of the transformer body is effectively reduced. The soundproof oil tank of the transformer has a simple structure and is easy to manufacture and install.

[0007] According to its abstract, CN105810419 relates to a noise reduction device for a transformer, a transformer oil tank and a transformer. The noise reduction device includes a noise reduction plate and an insulating layer for covering the surface of the noise reduction plate, wherein the noise reduction plate includes at least two paperboard layers and a metal plate layer arranged between adjacent paperboard layers; in addition, the topmost layer and the bottommost layer of the noise reduction plate are both paperboard layers. The noise reduction device has the advantages of low cost and good noise reduction effect; in addition, the noise reduction device can be arranged in the free space in the transformer oil tank, so that there is no need to avoid the line and the volume of the transformer does not need to be expanded; at the same time, the inner wall of the transformer is straight, so the structure of the noise reduction device is simplified; therefore, the noise reduction device is easy to process and easy to realize industrial production.

[0008] According to its abstract, EP0073401 relates to shielding walls supported on the tank side walls by means of a large-area compressible intermediate layer, which at the same time represents a thermal insulation wall for reducing noise emissions, since the natural frequency of the vibration system is less than 0.7 times the power frequency, the vibration system being in each case composed of the portion of the shielding wall located between the attachment point and the relevant portion of the intermediate layer. The use of such a device is particularly economical and applicable in high-power transformers.

[0009] According to its abstract, JP2017011140 relates to a transformer capable of reducing noise by improving a fixing method of a magnetic shield provided in a transformer box. The transformer is composed of: an iron core having an iron core leg and an iron core yoke; a winding wound on the iron core leg; a box having an iron core and a winding therein; and a magnetic shield provided in the box opposite to the winding. After a seat is fixed on an inner surface of the box, a buffer member is provided on the seat, and the magnetic shield is fixed to the buffer member.

[0010] US 3,175,173 relates to a device for reducing audible noise generated by an electrical device during normal operation, and more particularly to a noise reduction device for an electrical induction device of the type having a magnetic flux producing member contained in a metal housing.

[0011] According to its abstract, US4373608 relates to a tuned sound barrier for a machine radiating sound primarily at a few constant discrete frequencies, comprising an array of mechanical resonators distributed on the surface of the sound barrier. Each resonator of the array is tuned to present a high mechanical impedance to the transmission of mechanical vibrations at one of the discrete frequencies emitted by the source machine. The tuned sound barrier can be a freestanding sound barrier or an attachment to the machine housing.

[0012] According to its abstract, WO2008080820 relates to an electric transformer / reactor immersed in oil, which comprises a transformer / reactor core and a winding housed in a box, the box comprising a box bottom plate and a box wall, and a foundation supporting the box. An elongated continuous strip forming a closed frame is arranged between the base plate and the foundation, and the outer periphery of the base plate extends beyond the inner periphery of the frame, thereby enclosing an air volume within the frame, the base plate, and the foundation. The box and the support can reduce the sound emitted by the transformer / reactor.

[0013] According to its abstract, SE1651719 relates to a scheme for attenuation of low frequency sounds around electric machines. The general scheme is to enclose the machine with walls of sufficiently high quality without increasing costs. The first aspect of the invention using sand-filled panels is a high efficiency reduction of noise at low frequencies, in particular at 100 Hz and 120 Hz. This corresponds to the load noise of the mainstream AC transformer and the sound generated by the Maxwell forces of the shunt reactor. Summary of the invention

[0014] Therefore, it is an object of the present disclosure to provide an improved transformer arrangement which exhibits reduced noise radiation. More specifically, it is an object of the present disclosure to provide a transformer arrangement which is capable of reducing load noise.

[0015] According to the main aspect of the present disclosure, the object is achieved by a transformer device, which includes a transformer, which includes at least one phase winding. The phase winding has a coil turn around a coil axis. The transformer device also includes a transformer box, which has a wall forming a housing, and the transformer is arranged in the housing. The housing contains an incompressible medium, and the transformer is immersed in it. A partition is arranged in the transformer box, and the partition is located between the wall of the transformer box and at least one phase winding of the transformer. The partition has an inner surface facing the transformer and an outer surface facing the wall. The partition is also arranged spaced apart from at least one phase winding of the transformer. The transformer has a first extension along a first axis parallel to the coil axis, a second extension along the second axis, and a third extension along the third axis. The first axis, the second axis, and the third axis are perpendicular to each other. The transformer has a lateral side parallel to the coil axis, a first end along the first axis, and an opposite second end along the first axis. The transformer box has a first wall adjacent to the first end of the transformer and extending transversely to the first axis, and an opposite second wall adjacent to the second end of the transformer and extending transversely to the first axis. The partition has at least one first portion and at least one second portion, each extending transversely to the first axis, wherein the at least one first portion is arranged between the first end of the transformer and the first wall of the transformer tank, and the at least one second portion is arranged between the second end of the transformer and the second wall of the transformer tank.

[0016] It has been shown that the main mechanism for mechanical excitation of the tank walls by the oil is related to the incompressibility of the oil on the one hand and the inertia of the oil on the other hand. The fact that the oil is acoustically incompressible means that any volume change caused by the winding vibrations will inevitably translate into an equal volume change of the tank. The net volume change of the tank is in turn achieved via the structural modes of the tank, which are organized in such a way that a net volume change is established. At low frequencies, this net volume change can be considered as the result of a so-called monopole tank velocity distribution, and it is known that this global distribution has such a high radiation efficiency that it may mask the noise contribution of other local tank modal noise contributions. The latter is sometimes called a volume-preserving local dipole distribution, which has a much lower radiation efficiency than the global monopole distribution.

[0017] The fact that the entire oil volume can be considered acoustically incompressible also means that its inertia plays an important role, since the volume is nothing more than a large acoustically reactive near field, which means that the oil excites the tank by its inertial forces rather than by pressure induced by compressibility. An incompressible medium is a medium whose volume or density does not change with pressure. True incompressibility exists only in theory. However, the term "incompressible" as used in this disclosure is meant to refer to a nearly incompressible medium within the frequency range of interest to this disclosure. In the present disclosure, the medium may be an electrically insulating medium, such as mineral oil.

[0018] Generally, one method to mitigate the noise radiation mechanism of the transformer tank wall is to insert a barrier between the winding and the tank wall to protect the tank wall from the inertial force of the incompressible medium. With the disclosed transformer device, a noise reduction partition is arranged between the transformer and the transformer tank wall, separated from at least one phase winding. Therefore, the partition is separated from the direct structural vibration of the source (i.e., the transformer / phase winding) and is configured to block the inertia of the incompressible medium emanating from the phase winding, thereby reducing the vibration at the tank wall.

[0019] For the purposes of this disclosure, a transformer is defined as having a height equal to the height of at least one phase winding. Furthermore, the height of at least one phase winding is defined as including the thickness of the platen at each end of the at least one phase winding. The term "height" is not limited to a vertical extension. It more precisely refers to an extension generally along the coil axis.

[0020] In order to cover a larger portion of the transmission path of the vibration from the source, the partition may have a first portion and a second portion in addition to the lateral portion. The first portion and the second portion may be configured to block the inertial force of the incompressible medium at the first end and the second end of the transformer. In some transformer applications, the space along the lateral side of the transformer is limited. In this case, the first portion and the second portion of the partition may still be arranged at the ends of the transformer.

[0021] Optionally, the baffle is configured to have no structural resonance at twice the network frequency.

[0022] The network frequency is the frequency at which the transformer operates, which results in mechanical vibrations at twice the network frequency. The network frequency is typically 50 Hz or 60 Hz. For example, the partition is thus configured to have no structural resonance at 100 Hz and / or 120 Hz. Preferably, the partition is configured to have no structural resonance in a range of up to six times the network frequency.

[0023] Therefore, a stiff (ideally, rigid) partition is arranged as a barrier between the winding and the tank. Rigid means that the partition is configured to exhibit a structural resonance far exceeding twice the network frequency and the residual average static deflection of the partition due to the oscillating inertial forces of the surrounding incompressible medium is much smaller than the average particle displacement of the medium. Therefore, the inertial forces of the incompressible medium are not transmitted beyond the partition, or at least are significantly reduced beyond the partition.

[0024] Optionally, the inner surface of the partition includes a volume compressible lining.

[0025] Under the influence of electromagnetic forces acting on the structural components of the transformer, these components undergo changes in both shape and volume. The latter, exerted on an incompressible medium, causes the box to vibrate with the same volume change, resulting in a net volume change of the air surrounding the box, which in turn leads to a higher noise level compared to the case where the net volume change of the box is zero. It is proposed here that this zero net volume change of the box is caused by a volume compressible liner, which (rather than the box) absorbs the volume change of the transformer structural components. The remaining inertial forces are blocked and reduced by the rigid part of the partition.

[0026] The bulk modulus of the lining should be significantly smaller than the bulk modulus of the surrounding incompressible medium. The bulk modulus describes the elastic properties of a solid or fluid when pressure is applied to all surfaces. The bulk modulus is sometimes referred to as incompressibility and is a measure of the ability of a substance to undergo a change in volume when compressed on all sides. For example, the bulk modulus of electrical insulating transformer oil is about 1.7 GPa. However, preferably, the bulk modulus of the lining is smaller, such as about 0.1-0.2 GPa, or even smaller.

[0027] Optionally, the separator comprises a particulate material.

[0028] Energy propagation in an acoustic medium can generally be attenuated and redirected by introducing changes in impedance experienced by particle motion in the medium, and the present disclosure achieves this change in impedance by introducing a bulk substance in the form of a granular compound, thereby providing an inelastic and highly damped barrier without inherent resonance.

[0029] As an alternative to rigid partitions and rigid partitions including a volume compressible liner, the partitions may include granular material. The partitions may be configured as a plurality of pockets that include granular material, such as sand. The granular material should be heavier than the incompressible medium. For example, the density of electrical insulating transformer oil is about 870 kg / m 3 In this case, the density of the granular material can exceed 870kg / m 3 , preferably at least 1600 kg / m 3 .

[0030] Alternatively, the partition may be arranged on a wall of the transformer tank. Thus, the partition comprising the granular material may be arranged on the inner side of the wall of the transformer tank. Thus, the bag or sack containing the granular material may be attached to the wall by conventional fixing means, preferably covering the wall.

[0031] Optionally, the partition is spaced from the wall of the transformer box. Any of the rigid partition, composite partition, or heavy / soft partition can be arranged in the transformer box, keeping a certain distance from at least one phase winding of the transformer and the box wall. In this way, the partition is neither in direct mechanical contact with the phase winding nor in direct mechanical contact with the box wall. Thus, mechanical vibration is avoided from being directly transmitted from at least one phase winding to the partition, and directly from the partition to the box wall.

[0032] Optionally, at any point of the partition, the distance between said point of the partition and the nearest part of at least one phase winding of the transformer is smaller than the distance between said point of the partition and the nearest part of the wall of the transformer tank.

[0033] Acoustically, it is advantageous for the diaphragm to be arranged as close as possible to the vibration source in order to efficiently block most of the inertial forces generated by the transformer during operation.

[0034] Optionally, the transformer has lateral sides parallel to the coil axis, and the partition has at least one lateral portion aligned with the lateral sides of the transformer, and wherein the at least one lateral portion of the partition surrounds the transformer along a plane transverse to the coil axis.

[0035] The lateral portion of the partition is not limited to parallel alignment with the lateral sides of the transformer. The lateral portion may be inclined relative to the coil axis.

[0036] From the perspective of reducing load noise, it is preferred that the partition completely surround the transformer and that there are no openings in the partition. However, in practice, for cooling purposes, design considerations require that the incompressible medium can flow relatively freely around at least one phase winding. In addition, the partition requires a large number of electrical connections between the transformer and the outside of the transformer tank. Therefore, a lateral portion of the partition surrounding or enclosing the lateral side of the transformer or at least one phase winding is considered to be a preferred configuration for the partition. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Other objects, advantages, and features of the present disclosure will become apparent from the following description of one or more embodiments with reference to the accompanying drawings, in which:

[0038] Figure 1 A perspective view of an exemplary embodiment of the present disclosure is shown.

[0039] Figure 2 A perspective view of an exemplary embodiment of the present disclosure is shown.

[0040] Figure 3 A perspective view of an exemplary embodiment of the present disclosure is shown.

[0041] Figure 4 A perspective view of a separator according to an exemplary embodiment of the present disclosure is shown.

[0042] Figure 5 A perspective view of an exemplary embodiment of the present disclosure is shown.

[0043] Figure 6 A top view of a separator according to an exemplary embodiment of the present disclosure is shown.

[0044] Figure 7 A perspective detail of a baffle according to an exemplary embodiment of the present disclosure is shown.

[0045] Figure 8 Simulation results of an exemplary embodiment of the present disclosure are shown. DETAILED DESCRIPTION

[0046] The present disclosure is developed in more detail below with reference to the accompanying drawings showing examples of embodiments. The present disclosure should not be considered as being limited to the examples of embodiments described. Throughout the description, the same numbers represent the same elements.

[0047] Figure 1 A transformer arrangement 100 is shown, comprising a transformer 10, which comprises at least one phase winding 12. The transformer 10 shown has three phase windings 12. The phase winding 12 has coil turns around a coil axis c. The transformer arrangement 100 further comprises a transformer tank 20, which has a wall 22 forming a housing, in which the transformer 10 is arranged. In the example shown, the transformer tank 20 is shown open to the observer to expose the interior of the transformer 10. In practical applications, the transformer tank is obviously closed on all sides. The housing contains an incompressible medium, in which the transformer 10 is immersed. A partition 30 is arranged in the transformer tank 20, between the wall 22 of the transformer tank 20 and at least one phase winding 12 of the transformer 10. The partition 30 has an inner surface facing the transformer and an outer surface facing the wall. The partition 30 is arranged spaced apart from the at least one phase winding 12 of the transformer 10. In other words, the partition is not in direct mechanical contact with any phase winding 12 of the transformer 10. Therefore, the partition is separated from the direct structural vibration of at least one phase winding, which is generated during the operation of the transformer. The partition 30 is configured to block the inertial force of the incompressible medium emanating from the phase winding 12, thereby reducing the vibration of the incompressible medium at the tank wall 22. Therefore, due to the movement of the incompressible medium, the displacement of the tank wall 22 will also be reduced, which in turn leads to a reduction in the load noise radiated by the tank wall 22.

[0048] The transformer operates at a given network frequency. Typically, the network frequency is 50 Hz or 60 Hz, which results in structural vibration of at least one phase winding 12 at twice the network frequency (i.e., 100 Hz or 120 Hz, respectively). The partition 30 can be configured to have no structural resonance at twice the network frequency. Preferably, the partition 30 is configured to have no structural resonance in a range up to six times the network frequency. Therefore, the partition 30 is not significantly excited by the vibration transmitted to the partition 30 from at least one phase winding 12 through the incompressible medium.

[0049] Alternatively, if Figure 6 As shown, the inner surface of the partition 30 may include a volume compressible lining 34. The bulk modulus of the lining should be significantly smaller than the bulk modulus of the surrounding incompressible medium. For example, the bulk modulus of electrical insulating transformer oil is about 1.7 GPa. However, preferably, the bulk modulus of the lining is less than 1.7 GPa, preferably 0.1-0.2 GPa, or even smaller.

[0050] Alternatively, the separator 30 may comprise a granular material (rather than being rigid), such as a heavy mass having no rigidity but significant inherent damping. The separator may be configured as a plurality of pockets 38, such as Figure 7 As shown, these bags 38 include granular material, such as sand. Figure 7 The exemplary embodiment of FIG. 1 shows only a portion of the partition 30. As with the other embodiments, the partition 30 is intended to surround the transformer 10. The granular material should be heavy relative to the incompressible medium. For example, the density of the oil in the electrical insulation transformer is about 870 kg / m 3 In this case, the density of the granular material should preferably be higher than 870 kg / m 3 , preferably at least 1600 kg / m 3 .

[0051] Such a partition 30 comprising granular material may be arranged on the wall 22 of the transformer tank. Thus, the partition 30 comprising granular material may be arranged on the inner side of the wall 22 of the transformer tank. Thus, the bag 38 comprising granular material may be attached to the wall 22 by conventional fixing means, preferably completely covering the wall 22.

[0052] In addition to being spaced apart from at least one phase winding 12 of the transformer 10, the partition 30 may also be spaced apart from the wall 22 of the transformer tank 20. Any of the rigid partitions, composite partitions, or granular partitions described above may be disposed in the transformer tank 20, spaced apart from at least one phase winding 12 of the transformer 10 and the tank wall 22. The partition 30 comprising granular material may be spaced apart from the tank wall 22 using a support structure (not shown) for suspending a bag 38 comprising granular material in an incompressible medium.

[0053] The transformer 10 may have a first extension along a first axis z parallel to the coil axis c, a second extension along a second axis x, and a third extension along a third axis y. The first axis, the second axis, and the third axis are perpendicular to each other. The transformer 10 has a lateral side parallel to the coil axis c.

[0054] The partition 30 may have at least one transverse portion 32 aligned at a transverse side of the transformer 10. The at least one transverse portion 32 of the partition 30 surrounds the transformer 10. The at least one transverse portion may have a height h along the first axis z. The height h of the at least one transverse portion 32 may be equal to the height H of the at least one phase winding 12. In the case of a plurality of transverse portions 32, the sum of the individual heights h may be equal to or less than the height H of the at least one phase winding 12. In order to cool the at least one phase winding 32, the sum of the heights h of the individual transverse portions is preferably less than the height H of the at least one phase winding 12.

[0055] The transformer 10 may have a first end along a first axis z and an opposite second end along the first axis z. The transformer tank 20 also has a first wall 22' extending transverse to the first axis z and an opposite second wall 22" extending transverse to the first axis z.

[0056] As described in the invention summary section of the present disclosure, the transformer 10 is defined as having a height equal to the height H of at least one phase winding 12, and the height of the phase winding 12 also includes the thickness of the pressure plates 14', 14" arranged at the ends of the phase winding 12. Therefore, the first end of the transformer 10 is defined herein as including at least one first pressure plate 14' of at least one phase winding 12, and the second end of the transformer 10 is defined as including at least one second pressure plate 14" of at least one phase winding 12.

[0057] like Figure 2 As shown, at least one transverse portion 32 of the partition 30 may include two transverse portions. One transverse portion 32 is arranged at the first end of the transformer 10 and one transverse portion 32 is arranged at the second end of the transformer. This configuration may be preferred because it can be imagined that the sound pressure in the incompressible medium is higher at the ends of at least one phase winding 12, that is, near the first pressure plate 14' and the second pressure plate 14". Therefore, arranging the transverse portion 32 around the first and second ends of the transformer 10 can be an effective way to block the inertial force of the incompressible medium, while leaving a major portion of the at least one phase winding 12 without a partition to improve the cooling efficiency of the incompressible medium around the at least one phase winding 12.

[0058] Figure 3 and Figure 4Another configuration is shown, in which the separator 30 has a profile that closely matches at least one phase winding 12. In the depicted example, the separator 30 includes two transverse sections 32, each of which includes three connected tubular sections 32a, 32b, 32c, which conform to the cylindrical shape of the three phase windings 12. In this way, the separator 30 is equidistant but closely spaced from at least one phase winding 12 on the circumference of the coil turns, thereby effectively blocking the inertial force of the incompressible medium.

[0059] Figure 5 Another configuration of the partition 30 is shown, wherein the partition 30 has at least one first portion 32' and at least one second portion 32", both extending transversely to the first axis z, and wherein the at least one first portion 32' is arranged between the first end of the transformer 10 and the first wall 22' of the transformer tank 20, and the at least one second portion 32" is arranged between the second end of the transformer 10 and the second wall 22" of the transformer tank 20. Thereby, the partition 30 is configured to cover a larger part of the transmission path of the inertial force caused by the vibration of the end of at least one phase winding 12. If at least one transverse portion 32 is used in combination with the first portion 32' and the second portion 32", the first portion 32' and the second portion 32" can be mechanically connected, for example welded to the transverse portion 32.

[0060] Rigid partitions, partitions including a volume compressible liner 34, and partitions including granular material can all be used according to Figure 1-5 However, only the partitions comprising granular material can advantageously be arranged directly on the transformer tank wall 22 .

[0061] Figure 8 Graph B shows the simulation results of the acoustic power of the transformer tank as a function of frequency. Graph B shows the transformer device 100 according to the present disclosure, which has a partition 30 including a volume compressible liner 34. Graph A shows the transformer arrangement without a partition, i.e., a conventional transformer arrangement. It can be seen that the partition 30 contributes significantly to reducing the load noise.

Claims

1. A transformer device (100), comprising: - a transformer (10), comprising at least one phase winding (12), the phase winding (12) having coil turns around a coil axis (c), the transformer having a first extension along a first axis (z) parallel to the coil axis (c), a second extension along a second axis (x) and a third extension along a third axis (y), the first axis, the second axis and the third axis being perpendicular to each other, and wherein the transformer (10) has lateral sides parallel to the coil axis (c); - a transformer tank (20) having walls (22) forming a housing in which the transformer (10) is arranged, the housing containing an incompressible medium in which the transformer is immersed; a partition (30) arranged in the transformer box (20), the partition being located between the wall (22) of the transformer box and the at least one phase winding (12) of the transformer (10), the partition (30) having an inner surface facing the transformer and an outer surface facing the wall, the partition (30) being arranged spaced apart from the at least one phase winding (12) of the transformer (10), and Characterized in that the transformer has a first end along the first axis (z) and an opposite second end along the first axis (z), and wherein the transformer box (20) has a first wall (22') adjacent to the first end of the transformer (10) and extending transversely to the first axis (z) and an opposite second wall (22") adjacent to the second end of the transformer (10) and extending transversely to the first axis (z), wherein the partition (30) has at least one first portion (32') and at least one second portion (32") both extending transversely to the first axis (z), and wherein wherein the at least one first portion (32') is arranged between the first end of the transformer (10) and the first wall (22') of the transformer tank (22), and the at least one second portion (32") is arranged between the second end of the transformer (10) and the second wall (22") of the transformer tank (20), and wherein the partition (30) has at least one lateral portion (32) aligned with the lateral side of the transformer (10), and wherein the at least one lateral portion (32) of the partition (30) surrounds the transformer (30).

2. The transformer device (100) according to claim 1, wherein: The baffle (30) is configured to have no structural resonance at twice the network frequency.

3. The transformer device (100) according to claim 1 or 2, wherein: The inner surface of the partition (30) includes a volume compressible liner (34).

4. The transformer device (100) according to claim 3, wherein: The bulk modulus of the lining (34) is ≤1.7 GPa.

5. The transformer device (100) according to claim 1, wherein: The separator (30) comprises a granular material.

6. The transformer device (100) according to claim 5, wherein: The density of the granular material is greater than 870 kg / m 3 , or more preferably, greater than 1600 kg / m 3 .

7. The transformer device (100) according to claim 5 or 6, wherein: The partition plate (30) is arranged on the wall (22) of the transformer tank (20).

8. The transformer device (100) according to any one of claims 1 to 6, wherein: The partition plate (30) is arranged to be spaced apart from the wall (22) of the transformer tank (20).

9. The transformer device (100) according to claim 8, wherein: At any point of the partition (30), the distance between the point of the partition (30) and the nearest part of the at least one phase winding (12) of the transformer is smaller than the distance between the point of the partition (30) and the nearest part of the wall (22) of the transformer tank (20).

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