Transformer arrangement
The disclosure relates to a transformer arrangement comprising a transformer which comprises at least one phase winding. The phase winding has coil turns around a coil axis. The transformer arrangement further comprises a transformer tank having walls forming an enclosure in which the transformer is arranged. The enclosure contains an incompressible medium in which the transformer is immersed. A screen is arranged in the transformer tank, between the walls of the transformer tank and the at least one phase winding of the transformer. The screen has an inner, transformer-facing, surface and an outer, wall-facing, surface. The screen is further arranged distanced from the at least one phase winding. The transformer has lateral sides parallel with the coil axis. The screen has at least one lateral part aligned with the lateral sides of the transformer, and wherein the at least one lateral part of the screen circumscribes the transformer.
1 . A transformer arrangement comprising
a transformer comprising at least one phase winding, said phase winding having coil turns around a coil axis, the transformer having a first extension along a first axis parallel with the coil axis, a second extension along a second axis and a third extension along a third axis, said first, second and third axes being perpendicular to each other, and wherein the transformer has lateral sides parallel with the coil axis,
a transformer tank having walls forming an enclosure in which said transformer is arranged, said enclosure containing an incompressible medium in which the transformer is immersed,
a screen arranged in said transformer tank, between the walls of the transformer tank and the at least one phase winding of the transformer, said screen having an inner, transformer-facing, surface and an outer, wall-facing, surface, and
wherein the screen is arranged distanced from the at least one phase winding of the transformer, in that the screen has at least two lateral parts aligned with the lateral sides of the transformer, and wherein each of the at least two lateral parts of the screen comprises a continuous band that circumscribes the transformer and the at least two lateral parts have a height along the first axis, a sum of the individual heights being equal to, or less, than a height of the at least one phase winding.
2 . The transformer arrangement according to claim 1 , wherein the screen is configured to be free from structural resonances at twice a network frequency by being rigid, by comprising a volumetrically compressible lining, or by comprising a granular material.
3 . The transformer arrangement according to claim 1 , wherein the inner surface of the screen comprises a volumetrically compressible lining.
4 . The transformer arrangement according to claim 3 , wherein the lining has a bulk modulus ≤1.7 GPa.
5 . The transformer arrangement according to claim 1 , wherein the screen comprises a granular material.
6 . The transformer arrangement according to claim 5 , wherein the granular material has a density of more than 870 kg/m 3 , or more preferably a density of more than 1600 kg/m 3 .
7 . The transformer arrangement according to claim 5 , wherein the screen is arranged on the walls of said transformer tank.
8 . The transformer arrangement according to claim 1 , wherein the screen is arranged distanced from the walls of the transformer tank.
9 . The transformer arrangement according to claim 8 , wherein, in any point of the screen, a distance between said point of the screen and a closest part of the at least one phase winding of the transformer is less than a distance between said point of the screen and a closest part of the walls of the transformer tank.
10 . The transformer arrangement according to claim 1 , wherein the transformer has a first end along the first axis and an opposite second end along the first axis, and wherein the transformer tank has a first wall extending transversely to the first axis adjacent to the first end of the transformer and an opposite second wall extending transversely to the first axis, adjacent to the second end of the transformer, and wherein the screen has at least one first part and at least one second part, each extending transversely to the first axis and wherein the at least one first part is arranged between the first end of the transformer and the first wall of the transformer tank and the at least one second part is arranged between the second end of the transformer and the second wall of the transformer tank.