Transformer Configuration

Abstract

The present disclosure relates to a transformer arrangement (100) comprising a transformer (10) comprising at least one phase winding (12). The phase winding (12) has a coil winding centered about a coil axis (c). The transformer arrangement (100) further comprises a transformer tank (20) having a wall (22) forming an enclosure in which the transformer (10) is disposed. The enclosure contains an incompressible medium in which the transformer (10) is immersed. A screen (30) is disposed within the transformer tank (20) between the wall (22) of the transformer tank (20) and the at least one phase winding (12) of the transformer (10). The screen (30) has an inner transformer-facing surface and an outer wall-facing surface. The screen (30) is further disposed away from the at least one phase winding (12) of the transformer (10). The transformer tank (20) has a first wall (22') extending transversely to a first axis (z) adjacent a first end of the transformer (10) and an opposing second wall (22") extending transversely to the first axis (z) adjacent a second end of the transformer (10). The screen (30) has at least one first portion (32') and at least one second portion (32") each extending transversely to the first axis (z), the at least one first portion (32') being disposed 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") being disposed between the second end of the transformer (10) and the second wall (22") of the transformer tank (20).

Description

[Technical field]

[0001] Technical Field The present disclosure relates to a transformer configuration for load noise reduction. [Background technology]

[0002] background Transformers must comply with various requirements regarding noise levels. Transformers, immersed in electrically insulating oil in a transformer tank, vibrate during operation. The vibrations are transmitted from the transformer windings through the oil to the tank walls and can lead to significant vibration displacements of the tank walls, resulting in noise generation. Three main noise sources can be identified in transformers: no-load or core noise generated by magnetostriction, load noise generated by electromagnetic forces in the windings, and noise due to auxiliary equipment such as fans and pumps used in the cooling system. Of these three, load noise contributes significantly to the total noise, especially for larger units.

[0003] Today's solutions to reduce noise are inefficient, costly, and applied far away from the source and primary transmission path of the load noise. Traditional solutions are also often bulky and impractical, such as sound panels and damping layers attached to the outside of the tank wall. Filling the tank structural elements with sand is another low-noise solution, but mainly for core noise and with limited impact on load noise. Traditional solutions are difficult to optimize and standardize for off-the-shelf, routine design work, due to the complex vibration / radiation characteristics of the transformer tank in which the transformer is enclosed. There can also be large unit-to-unit variations.

[0004] According to its abstract, WO 0101425 relates to a sound absorbing device for a stationary induction machine having an active part, an insulating fluid surrounding the active part and a tank in which the insulating fluid is enclosed. The sound absorbing device comprises a gas-filled cavity and an elastic membrane surrounding the gas-filled cavity, thus obtaining a highly compressible sound absorbing device. In the induction machine, the device is arranged between the active part of the induction machine and the tank and is spaced from the inside of the tank. The sound absorbing device preferably has an extent in one plane, whereby the device has a membrane part facing the active part and a membrane part facing the tank. Preferably, at least one of the membrane parts has at least one corrugated region and a spacer membrane is arranged in the cavity in contact with the membrane part at least at two points.

[0005] According to its abstract, JP 10106854 A relates to a fixed induction electric device capable of reducing noise even if the device configuration is made compact. A resonance type silencer having an internal cavity with partial openings is provided on the inner surface of the tank. The silencer is set to a frequency that resonates with the frequency of noise generated within the tank, so that the noise generated within the tank can be reduced by resonating with the frequency of the noise. Therefore, the noise radiated from the tank to the outside can be reduced.

[0006] According to its abstract, China Patent Application Publication No. 201732653 relates to a soundproof oil tank structure for a transformer with an oil tank body, in which the inner wall of the oil tank body is provided with a composite damping steel plate, and when the inner wall of the oil tank body is provided with a magnetic shield, the inner and outer sides of the magnetic shield are respectively provided with two layers of composite damping steel plates sandwiched by the clamping plates of the magnetic shield, and when the inner wall of the oil tank body is not provided with a magnetic shield, the composite damping steel plate is fixed by a mounting seat on the inner wall of the oil tank body. By disposing the composite damping steel plate on the inner wall of the transformer oil tank body, the noise of the transformer body is effectively reduced. The soundproof oil tank structure for a transformer has a simple structure and is convenient to manufacture and install.

[0007] According to its abstract, China Patent Publication No. 105810419 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, the noise reduction plate includes at least two paperboard layers and a metal plate layer disposed between adjacent paperboard layers, and the top layer and the bottom 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, and furthermore, the noise reduction device can be arranged in the free space in the transformer oil tank, so that the line avoidance and volume expansion of the transformer are not required, while the inner wall of the transformer is flat and linear, so that the structure of the noise reduction device can be simplified, so that it is easy to process and easy to realize industrial production.

[0008] According to its abstract, EP 0 073 401 A relates to a shielding wall which is supported on a tank side wall via a large-area compressible intermediate layer and which at the same time represents an insulating wall for reducing noise radiation, since in each case the natural frequency of the vibration system consisting of the part of the shielding wall located between the attachment point and the relevant part of the intermediate layer is less than 0.7 times the main frequency. The use of this configuration is particularly economically applicable to high-power transformers.

[0009] According to its abstract, JP2017011140A relates to a transformer capable of reducing noise by improving the fixing method of a magnetic shield disposed in a transformer tank. The transformer is composed of an iron core having an iron core leg and an iron core yoke, a winding wound around the iron core leg, a tank having the iron core and the winding inside, and a magnetic shield disposed inside the tank facing the winding. After a sheet is fixed to the inner surface of the tank, a buffer member is placed on the sheet, and the magnetic shield is fixed to the buffer member.

[0010] U.S. Patent Application Publication No. 3,175,173 relates to means for reducing audible noise generated by electrical equipment during normal operation, and more particularly to a noise reduction device for electrical induction devices of the type having flux-producing members housed within a metallic enclosure.

[0011] According to its abstract, U.S. Patent Application Publication No. 4,373,608 relates to a tuned noise barrier for machines that radiate sound primarily at several fixed discrete frequencies, and includes an array of mechanical resonators distributed over the surface of the barrier. Each resonator in the array is tuned to present a high mechanical impedance to the transmission of mechanical vibrations at one of the discrete frequencies radiated by the source machine. The tuned noise barrier may be either a free-standing noise barrier or an attachment to the housing of the machine.

[0012] According to its abstract, WO2008080820 relates to an oil-immersed power transformer / reactor comprising a transformer / reactor core, a winding housed within a tank comprising a tank bottom plate and tank walls, and a foundation supporting the tank. An elongated continuous band forming a closed frame is disposed between the bottom plate and the foundation, the outer periphery of the bottom plate extending outside the inner periphery of the frame, thereby enclosing an air volume within the frame, bottom plate, and foundation. The tank, support, reduces sound radiated from the transformer / reactor.

[0013] According to its abstract, Swedish patent application 1651719 concerns a solution for low frequency sound attenuation around electric machines. The common solution is to surround the machine with a wall that is not high cost and has a sufficiently high mass. The first aspect of the invention with sand-filled panels is to reduce noise with high efficiency at low frequencies, especially at 100Hz and 120Hz. This corresponds to the load noise of the main AC transformer and the sound generated by the Maxwell forces of the shunt reactor. Summary of the Invention [Problem to be solved by the invention]

[0014] overview It is therefore an object of the present disclosure to provide an improved transformer configuration that exhibits reduced noise emissions. More specifically, it is an object of the present disclosure to provide a transformer configuration that can reduce load noise. [Means for solving the problem]

[0015] According to a main aspect of the disclosure, this object is achieved by a transformer arrangement comprising a transformer comprising at least one phase winding. The phase winding has a coil winding centered on a coil axis. The transformer arrangement further comprises a transformer tank having a wall forming an enclosure in which the transformer is disposed. The enclosure contains a non-compressible medium in which the transformer is immersed. A screen is disposed within the transformer tank between the wall of the transformer tank and the at least one phase winding of the transformer. The screen has a surface facing the inner transformer and a surface facing the outer wall. The screen is further disposed away from the 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 a second axis, and a third extension along a third axis. The first, second and third axes are perpendicular to each other. The transformer has a side parallel to the coil axis, a first end along the first axis, and an opposite second end along the first axis. The transformer tank has a first wall extending transversely to the first axis adjacent the first end of the transformer and an opposite second wall extending transversely to the first axis adjacent the second end of the transformer. The screen has at least one first portion and at least one second portion each extending transversely to the first axis, the at least one first portion being disposed between the first end of the transformer and the first wall of the transformer tank, and the at least one second portion being disposed between the second end of the transformer and the second wall of the transformer tank.

[0016] Studies have shown that the main mechanism behind the oil mechanically exciting the tank walls is related to the incompressibility of the oil on the one hand and to its inertia on the other hand. Oil being acoustically incompressible means that any volume change brought about by the vibration of the windings is necessarily transformed into an equal volume change of the tank. The net tank volume change is realized by the structural modes of the tank which configure themselves so that a net volume change is established. At low frequencies, such a net volume change can be considered as the result of a so-called monopole tank velocity distribution, this global distribution is known to have such a high radiation efficiency that it can mask noise contributions from 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 in that the volume is nothing but a large acoustically reactive near-field, which means that the oil excites the tank by its inertial forces and not by pressure due to compressibility. An incompressible medium is one whose volume or density does not change with pressure. True incompressibility exists only in theory. However, the meaning of the term "incompressible" as used in this disclosure is a term that indicates a medium that is nearly incompressible in the frequency range of interest for this disclosure. The medium may be an electrically insulating medium, such as mineral oil, in this disclosure.

[0018] Generally, one method of mitigating the noise radiation mechanism of the transformer tank wall is to insert a barrier between the winding and the tank wall to shield the tank wall from the inertial forces of the incompressible media. With the disclosed transformer configuration, a noise reduction screen is placed between the transformer and the transformer tank wall, away from at least one phase winding. The screen is thereby configured to block the inertia of the incompressible media emanating from the phase winding, such that the vibrations are isolated from the source, i.e., direct structural vibrations of the transformer / phase winding, and are reduced at the tank wall.

[0019] For purposes of this disclosure, a transformer is defined as having a height equal to the height of the at least one phase winding. The height of the at least one phase winding is also defined to include the thickness of the backing plates at each end of the at least one phase winding. The term "height" is not limited to the vertical extension; rather, it refers to the extension generally along the coil axis.

[0020] To cover most of the transmission path of the vibration from the source, the screen may have a first portion and a second portion in addition to the side portion. The first portion and the second portion may be configured to block the inertial forces of the incompressible medium at the first end and the second end of the transformer. In some transformer applications, space is limited along the sides of the transformer. In such cases, the first and second portions of the screen may still be located at the ends of the transformer.

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

[0022] The network frequency is the frequency at which the transformer operates, resulting in mechanical vibrations at twice the network frequency. The network frequency is typically 50 Hz or 60 Hz. Thus, by way of example, the screen is configured to be free of structural resonance at 100 Hz and / or 120 Hz. Preferably, the screen is configured to be free of structural resonance within a range of up to six times the network frequency.

[0023] Hereby a stiff, ideally rigid, screen is placed as a barrier between the windings and the tank. By rigid, we mean that the screen is constructed such that it exhibits structural resonances well above twice the network frequency, such that the remaining average static deflection of the screen due to the vibratory inertial forces of the surrounding incompressible medium is much smaller than the average particle displacement of the medium. This ensures that the inertial forces of the incompressible medium are not transmitted across the screen, or are at least significantly reduced across the screen.

[0024] Optionally, the inner surface of the screen comprises a volume compressible lining. Under the action of electromagnetic forces acting on the transformer structural components, they undergo both a change in shape and a change in volume. The latter is imposed on the incompressible medium to the extent that the same volume change is forced on the tank vibrations, resulting in a net volume change of the air surrounding the tank, resulting in a much higher noise level compared to the case where the net volume change of the tank is zero. This zero net volume change of the tank is proposed here to be brought about by a volumetric compressible lining, which accounts for the volume change of the transformer structural components instead of the tank. The remaining inertial forces are blocked and reduced by the rigid part of the screen.

[0025] The bulk modulus of the lining must be significantly less than the bulk modulus of the surrounding incompressible medium. Bulk modulus describes the elastic properties of a solid or fluid when it is under pressure on all surfaces. Bulk modulus, sometimes called incompressibility, is a measure of a material's ability to withstand a change in volume when it is compressed on all sides. As an example, the bulk modulus of electrical insulating transformer oil is about 1.7 GPa. In that case, the bulk modulus of the lining is preferably smaller, such as about 0.1-0.2 GPa, or even less.

[0026] Optionally, the screen comprises a granular material. The propagation of energy in an acoustic medium can generally be attenuated and redirected by introducing a change in impedance experienced by particle motion within the medium, and the present disclosure provides this change in impedance by introducing mass in the form of a granular compound, providing an inelastic and highly damped barrier with no inherent resonance.

[0027] As an alternative to a rigid screen, and as an alternative to a rigid screen that includes a volume compressible lining, the screen can include a granular material. The screen may be configured as a plurality of pockets, the pockets containing the granular material, such as sand. The granular material must be heavier than the incompressible medium. As an example, electrical insulating transformer oil has a mass of approximately 870 kg / m 3 If the granular material has a density of 870 kg / m 3 More than 1600 kg / m 3 The density of the powder may be 0.01 to 0.01.

[0028] Optionally, a screen may be placed in the wall of said transformer tank. Thus, the screen containing the granular material may be placed inside the wall of the transformer tank. In this way, the pockets or bags containing the granular material may be attached to the wall by conventional fastening means, preferably covering the wall.

[0029] Optionally, the screen is located away from the wall of the transformer tank. Any of the described rigid screens, composite screens, or heavy / soft screens may be located in the transformer tank away from both the at least one phase winding of the transformer and the tank wall. In this way, the screen is not in direct mechanical contact with either the phase winding or the tank wall. This avoids the transmission of mechanical vibrations directly from the at least one phase winding to the screen and directly from the screen to the tank wall.

[0030] Optionally, at any point on the screen, the distance between said point on the screen and the nearest portion of at least one phase winding of the transformer is less than the distance between said point on the screen and the nearest portion of a wall of the transformer tank.

[0031] Acoustically, it is advantageous for the screen to be located as close as possible to the vibration source in order to effectively block most of the inertial forces emanating from the transformer during operation.

[0032] Optionally, the transformer has sides parallel to the coil axis, and the screen has at least one side portion aligned with a side of the transformer, and the at least one side portion of the screen circumscribes the transformer along a plane transverse to the coil axis.

[0033] The side portions of the screen are not limited to being aligned parallel to the sides of the transformer: the side portions may be angled relative to the coil axis.

[0034] From the standpoint of load noise reduction, it is preferred that the screen completely surround the transformer with no openings in the screen. In practice, however, design considerations require that the incompressible medium be able to flow relatively freely around at least one phase winding for cooling purposes. Additionally, the screen needs to allow for a number of electrical connections between the transformer and the outside of the transformer tank. Thus, a side portion of the screen surrounding or circumscribing the side of the transformer, or at least one phase winding, is considered the preferred configuration of the screen.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS Further objects and advantages as well as features of the present disclosure will become apparent from the following description of one or more embodiments which proceeds with reference to the accompanying drawings. [Brief description of the drawings]

[0036] [Figure 1] FIG. 1 is a perspective view of an exemplary embodiment of the present disclosure. [Diagram 2] FIG. 1 is a perspective view of an exemplary embodiment of the present disclosure. [Diagram 3] FIG. 1 is a perspective view of an exemplary embodiment of the present disclosure. [Figure 4] FIG. 1 is a perspective view of a screen according to an exemplary embodiment of the present disclosure. [Diagram 5] FIG. 1 is a perspective view of an exemplary embodiment of the present disclosure. [Figure 6] FIG. 2 is a top view of a screen according to an exemplary embodiment of the present disclosure. [Figure 7]FIG. 2 is a perspective detail view of a screen according to an exemplary embodiment of the present disclosure. [Figure 8] FIG. 1 illustrates simulation results of an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THEINVENTION The present disclosure will be developed in more detail below with reference to the attached drawings, which show example embodiments. The present disclosure should not be considered limited to the example embodiments described. Like numbers refer to like elements throughout the description.

[0038] FIG. 1 shows a transformer arrangement 100 comprising a transformer 10 comprising at least one phase winding 12. The illustrated transformer 10 comprises three phase windings 12. The phase winding 12 comprises a coil winding centered on a coil axis c. The transformer arrangement 100 further comprises a transformer tank 20 having a wall 22 forming an enclosure in which said transformer 10 is arranged. In the illustrated example, the transformer tank 20 is shown open to the observer to expose the transformer 10 inside. In reality, the transformer tank is obviously closed on all sides. The enclosure comprises an incompressible medium in which the transformer 10 is immersed. A screen 30 is arranged in the transformer tank 20 between the wall 22 of the transformer tank 20 and the at least one phase winding 12 of the transformer 10. The screen 30 has a surface facing the inner transformer and a surface facing the outer wall. The screen 30 is located away from at least one phase winding 12 of the transformer 10. In other words, the screen is not in direct mechanical contact with any of the phase windings 12 of the transformer 10. This isolates the screen from direct structural vibrations of the at least one phase winding that occur during the operation of the transformer. The screen 30 is configured to block the inertial forces of the incompressible medium emanating from the phase winding 12 so that the vibrations of the incompressible medium are reduced at the tank wall 22. As a result, the displacement of the tank wall 22 due to the movement of the incompressible medium is also reduced, which in turn leads to a reduction in the load noise radiated by the tank wall 22.

[0039] 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 screen 30 may be configured to be free of structural resonance at twice the network frequency. Preferably, the screen 30 is configured to be free of structural resonance within a range of up to six times the network frequency. This ensures that the screen 30 is not significantly excited by vibrations transmitted from at least one phase winding 12 through an incompressible medium to the screen 30.

[0040] Optionally, as shown in FIG. 6, the inner surface of the screen 30 may include a volume-compressible lining 34. The bulk modulus of the lining must be significantly less than the bulk modulus of the surrounding incompressible medium. As an example, the bulk modulus of electrical insulating transformer oil is about 1.7 GPa. In that case, it is preferable that the bulk modulus of the lining is less than 1.7 GPa, preferably 0.1-0.2 GPa or even less.

[0041] Alternatively, instead of being rigid, the screen 30 may comprise a granular material such as a heavy mass that has no rigidity but has significant inherent damping. The screen may be configured as a plurality of pockets 38, as shown in FIG. 7, which contain granular material such as sand. The exemplary embodiment of FIG. 7 shows only a portion of the screen 30. As with the other embodiments, the screen 30 is intended to circumscribe the transformer 10. The granular material must be heavy relative to the incompressible medium. As an example, electrical insulating transformer oil has a mass of approximately 870 kg / m 3 The granular material preferably has a density of 870 kg / m 3 Higher, preferably at least 1600 kg / m 3 The density should be 0.01 to 0.01.

[0042] Such a screen 30 containing granular material may be placed in the transformer tank wall 22. Thus, the screen 30 containing granular material may be placed inside the transformer tank wall 22. In this manner, the pockets 38 containing granular material may be attached to the wall 22 by conventional fastening means, preferably completely covering the wall 22.

[0043] In addition to being spaced apart from the at least one phase winding 12 of the transformer 10, the screen 30 may be located away from the wall 22 of the transformer tank 20. Any of the rigid screens, composite screens, or granular screens described above may be located within the transformer tank 20 away from both the at least one phase winding 12 of the transformer 10 and the tank wall 22. The screen 30 containing the granular material may be located away from the tank wall 22 using a support structure (not shown) to suspend the pockets 38 containing the granular material in the incompressible medium.

[0044] 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, second and third axes are perpendicular to each other. The transformer 10 has a side parallel to the coil axis c.

[0045] The screen 30 may have at least one side portion 32 aligned with a side of the transformer 10. The at least one side portion 32 of the screen 30 circumscribes the transformer 10. The at least one side portion may have a height h along the first axis z. The height h of the at least one side portion 32 may be equal to the height H of the at least one phase winding 12. In the case of multiple side portions 32, the sum of the individual heights h may be less than or equal to the height H of the at least one phase winding 12. For purposes of cooling the at least one phase winding 32, the sum of the heights h of the individual side portions is preferably less than the height H of the at least one phase winding 12.

[0046] The transformer 10 may have a first end along a first axis z and an opposing second end along the first axis z. The transformer tank 20 further has a first wall 22' extending transversely to the first axis z and an opposing second wall 22" extending transversely to the first axis z.

[0047] As discussed in the Summary of this disclosure, the transformer 10 is defined as having a height equal to the height H of the at least one phase winding 12, which height also includes the thickness of the pressure plates 14', 14" disposed at the ends of the phase winding 12. Thus, a first end of the transformer 10 is defined herein as including at least one first pressure plate 14' of the at least one phase winding 12, and a second end of the transformer 10 is defined herein as including at least one second pressure plate 14" of the at least one phase winding 12.

[0048] As shown in FIG. 2, the at least one side portion 32 of the screen 30 may include two side portions 32. One side portion 32 is disposed at a first end of the transformer 10, and one side portion 32 is disposed at a second end of the transformer. Such a configuration may be preferred because it is assumed that the sound pressure in the incompressible medium is higher near the ends of the at least one phase winding 12, i.e., the first pressure plate 14′ and the second pressure plate 14″. Thus, disposing the side portions 32 around the first and second ends of the transformer 10 may be an efficient way to resist the inertial forces of the incompressible medium while leaving most of the at least one phase winding 12 unscreened to improve the cooling efficiency of the incompressible medium around the at least one phase winding 12.

[0049] 3 and 4 show another configuration in which the screen 30 has a close-fitting contour to the at least one phase winding 12. In the example shown, the screen 30 comprises two side portions 32 with three connected tubular portions 32a, 32b, 32c that each fit the cylindrical shape of the three-phase winding 12. In this manner, the screen 30 is equidistantly but closely spaced from the at least one phase winding 12 along the circumference of the coil winding, providing efficient blocking of the inertial forces of the incompressible medium.

[0050] FIG. 5 shows a further configuration of the screen 30, in which the screen 30 has at least one first portion 32′ and at least one second portion 32″ each extending transversely to the first axis z, the at least one first portion 32′ being arranged between a first end of the transformer 10 and a first wall 22′ of the transformer tank 20, and the at least one second portion 32″ being arranged between a second end of the transformer 10 and a second wall 22″ of the transformer tank 20. This configures the screen 30 to cover most of the transmission path of the inertial force resulting from the vibration of the end of the at least one phase winding 12. When the at least one side portion 32 and the first portion 32′ and the second portion 32″ are applied in combination, the first portion 32′ and the second portion 32″ may be mechanically connected, for example welded, to the side portion 32.

[0051] The rigid screen including the volume compressible lining 34 and the screen including the granular material may all be constructed according to the embodiment shown in Figures 1 to 5. However, only the screen including the granular material may advantageously be placed directly on the transformer tank wall 22.

[0052] 8 shows the results of a simulation of how the acoustic forces in the transformer tank vary with frequency. Curve B shows the transformer configuration 100 according to the present disclosure, having a screen 30 with a volumetric compressible lining 34. Curve A shows the transformer configuration without a screen, i.e., the conventional transformer configuration. It can be seen that the screen 30 contributes significantly to the reduction of the load noise.

Claims

1. A transformer arrangement (100), comprising: a transformer (10) comprising at least one phase winding (12), said phase winding (12) having a coil winding centered on a coil axis (c); a transformer tank (20) having walls (22) forming an enclosure in which said transformer (10) is placed, said enclosure containing an incompressible medium in which said transformer (10) is immersed; a screen (30) arranged in the transformer tank (20) between the wall (22) of the transformer tank and the at least one phase winding (12) of the transformer (10), the screen (30) having an inner surface facing the transformer and an outer surface facing the wall, The screen (30) is positioned away from the at least one phase winding (12) of the transformer (10), 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, second, and third axes being perpendicular to one another, the transformer (10) having a side parallel to the coil axis (c), the transformer having a first end along the first axis (z) and an opposite second end along the first axis (z), the transformer tank (20) having a first wall (22) extending transversely to the first axis (z) adjacent the first end of the transformer (10). a first wall (22'') adjacent the second end of the transformer (10) and extending transversely to the first axis (z), the screen (30) having at least one first portion (32') and at least one second portion (32'') each extending transversely to the first axis (z), the at least one first portion (32') being disposed 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'') being disposed between the second end of the transformer (10) and the second wall (22'') of the transformer tank (20).

2. 2. The transformer arrangement (100) of claim 1, wherein the screen (30) is configured to be free of structural resonance at twice the network frequency.

3. 3. The transformer arrangement (100) of claim 1 or 2, wherein the inner surface of the screen (30) comprises a volume compressible lining (34).

4. 4. The transformer arrangement (100) of claim 3, wherein the lining (34) has a bulk modulus of 1.7 GPa or less.

5. The transformer arrangement (100) of claim 1, wherein the screen (30) comprises a granular material.

6. The granular material has a strength of 870 kg / m ３ More preferably, the density is greater than 1600 kg / m ３ The transformer arrangement (100) of claim 5, having a density of greater than

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

8. The transformer arrangement (100) according to any one of the preceding claims, wherein the screen (30) is positioned away from the wall (22) of the transformer tank (20).

9. 9. The transformer configuration (100) of claim 8, wherein at any point on the screen (30), a distance between the point on the screen (30) and a nearest portion of the at least one phase winding (12) of the transformer is less than a distance between the point on the screen (30) and a nearest portion of the wall (22) of the transformer tank (20).

10. 2. The transformer configuration (100) of claim 1, wherein the screen (30) has at least one side portion (32) aligned with the side of the transformer (10), and the at least one side portion (32) of the screen circumscribes the transformer (30).

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