Transformer and railbound vehicle

Abstract

The invention relates to an independently ventilating transformer (1). The invention also relates to a railbound vehicle (19) having a transformer (1) of this type.

Description

[0001] Description

[0002] Transformer and rail-bound vehicle

[0003] The invention relates to a transformer comprising a transformer active part, a vessel receiving the transformer active part and completely filled with transformer oil, a lid closing the vessel, an expansion vessel partially filled with transformer oil and partially filled with air, which is arranged laterally next to the vessel and whose lower, transformer oil-filled area is fluidically connected to the vessel in such a way that flow in both directions is possible, and a vent with integrated air dehumidifier, which is fluidically connected to the upper, air-filled area of ​​the expansion vessel.

[0004] Transformers of the type mentioned above are generally known in the prior art. They comprise a transformer active part arranged in a tank, which is normally a composite of core, windings, pressed parts, leads, and possibly other components. A transformer oil, with which the tank is completely filled, is used for electrical insulation and cooling of the active part. During operation, the transformer oil in transformers used, for example, in rail vehicles, is exposed to temperature amplitudes of up to 100 K. Since the volume of the transformer oil changes with temperature, the transformers are designed such that, in the event of expansion, excess medium is collected in an expansion vessel, which is filled with transformer oil in the lower section and with air in the upper section.The upper, air-filled section of the expansion vessel is connected to the atmosphere via a vent with an integrated dehumidifier. This allows the transformer oil flowing into the expansion vessel to displace the air contained within. The dehumidifier protects the transformer oil and prevents harmful moisture absorption from the ambient air. This prevents a reduction in dielectric strength and the formation of condensation within the expansion vessel.

[0005] Expansion vessels are typically positioned above the lid that seals the boiler. The fluid connection between the boiler and the expansion vessel is ideally located at the highest point of the boiler. This design has the advantage that any gases, such as air, that collect inside the boiler during transformer operation and rise due to buoyancy can escape and be drained via the expansion vessel.

[0006] However, due to the resulting increased height, positioning the expansion vessel above the boiler is not possible or at least undesirable in some applications. Therefore, expansion vessels are also positioned to the side of the boiler. In this case, gases accumulating in the boiler can no longer be completely vented into the expansion vessel. An increasing gas content in the boiler leads to a drop in the transformer oil level. If this level falls below a critical point, the necessary voltage clearances between electrical components of the active part can no longer be guaranteed. Consequently, the boiler must be manually vented at regular intervals. The success of the venting depends particularly on the position of the transformer during the process and on the expertise of the maintenance personnel.If the system is not properly vented, the transformer must be switched off before reaching the critical point to prevent lasting damage. This may, in some cases, lead to the complete shutdown of the train. The consequence is that the train must be towed to the nearest depot.

[0007] Starting from this state of the art, it is an object of the present invention to create a transformer of the type mentioned at the outset with an improved design.

[0008] To solve this problem, the present invention provides a transformer comprising a transformer active part, a vessel receiving the transformer active part and completely filled with transformer oil, a lid closing the vessel, an expansion vessel partially filled with transformer oil and partially filled with air, which is arranged laterally next to the vessel and whose lower, transformer oil-filled section is fluidically connected to the vessel in such a way that flow in both directions is possible, and a vent with integrated air dehumidifier, which is fluidically connected to the upper, air-filled section of the expansion vessel, characterized in that a first line equipped with a first check valve is provided, which fluidically connects the vessel to a transformer oil-filled section of the expansion vessel.wherein the first check valve allows flow exclusively through the first line towards the boiler, and that an air trap is provided arranged above the cover, the lower part of which is fluidically connected via a second line to an upper part of the boiler, in particular to a highest upper part of the boiler, and the upper part of which is fluidically connected via a third line equipped with a second check valve to the expansion vessel, in particular to a lower part of the expansion vessel filled with transformer oil, wherein the second check valve allows flow exclusively through the third line towards the expansion vessel.

[0009] The air trap serves to collect any gases that rise within the boiler. For this purpose, it is located above the lid and its lower section is fluidically connected to the upper section of the boiler via the second line, specifically to the highest point of the upper boiler section. To prevent manual venting of the air trap, its upper section is additionally connected to the expansion vessel via the third line, specifically to a lower section of the expansion vessel filled with transformer oil. To prevent air from being drawn back in during compression, the third line is equipped with the second check valve. This ensures that, during cooling, only transformer oil from the fluid section of the expansion vessel is drawn in through the first line.If the transformer heats up during operation, the air is purged from the air trap. In this operating state, the connection to the fluid section of the expansion vessel is prevented by the first check valve located in the first line.

[0010] A significant advantage of the transformer according to the invention is that, despite the expansion vessel being located laterally next to the boiler, manual venting of the boiler is no longer necessary. The boiler vents itself several times a day due to heating and cooling phases, preventing the accumulation of large quantities of gas in the boiler. This eliminates downtime and maintenance costs.

[0011] According to one embodiment of the present invention, the expansion vessel has chambers, the lower sections of which, filled with transformer oil, are each connected to one another via an oil connection line, and the upper sections of which, filled with air, are each connected to one another via an air connection line. Such chambers make it possible to divide the total volume of the expansion vessel into several smaller volumes, thereby achieving a great deal of design freedom.

[0012] Preferably, the chambers are positioned on opposite sides of the transformer, resulting in a uniform structure and thus a uniform weight distribution.

[0013] Furthermore, the present invention provides a rail-bound vehicle with a transformer according to the invention. Transformers according to the invention can be built flat, which is why they are particularly suitable for use in rail vehicles.

[0014] Further features and advantages of the present invention will become clear from the following description with reference to the accompanying drawing. Therein is

[0015] Figure 1 shows a schematic view of a transformer according to one embodiment of the present invention and

[0016] Figure 2 shows a schematic view of a rail-bound vehicle according to one embodiment of the present invention. The transformer 1 comprises as main components a transformer active part 2, a tank 3, a lid 4 closing the tank 3, an expansion vessel 5, a vent 6 with integrated dehumidifier and an air trap 7.

[0017] The transformer active part 2, which is in particular a composite of core, windings, pressed parts, conductor, and possibly other components, is positioned inside the tank 3, which is otherwise completely filled with transformer oil 8 for protection and cooling of the transformer active part. The expansion vessel 5, which is partially filled with transformer oil 8 and partially with air 9, is arranged laterally next to the tank 3. More precisely, the expansion vessel 5 is divided into two chambers 5a, 5b positioned on opposite sides of the tank 3, the lower sections of which, filled with transformer oil 8, are connected to each other via an oil connection line 10, and the upper sections of which, filled with air 9, are connected to each other via an air connection line 11.The vent 6, which communicates with the environment and has an integrated dehumidifier, is fluidically connected via an air outlet line 12 to the upper, air-filled section 9 of the expansion vessel 5. The lower section of the expansion vessel 5, filled with transformer oil 8, is fluidically connected via a first line 14, equipped with a first check valve 13, to the boiler 3, specifically to a section of the boiler 3 just below the cover 4, whereby the first check valve 13 allows flow exclusively through the first line 14 towards the boiler 3.In the embodiment shown here, a sub-chamber 5c, completely filled with transformer oil 8, is partitioned off from the chamber 5a, which is fluidically connected to the boiler 3 via the first line 14. The first line 14 opens into the lower part of sub-chamber 5c, and a further connecting line 15 is provided, which connects the upper part of sub-chamber 5c with the lower part of chamber 5a of the expansion vessel 5, which is also filled with transformer oil 8. The air trap 7 is arranged above the cover 4. A lower part of the air trap 7 is fluidically connected via a second line 16 to an upper part of the boiler 3, in particular to the highest point of the boiler 3.An upper area of ​​the air trap container 7 is fluidically connected to the expansion vessel 5 via a third line 18 equipped with a second check valve 17, in particular to a lower area of ​​the expansion vessel 5 filled with transformer oil 8, wherein the second check valve 17 allows only a flow through the third line 18 in the direction of the expansion vessel 5.

[0018] When the transformer oil 8 present in boiler 3 is heated during the operation of transformer 1, it expands and rises through the second line 16 into the air trap 7. Any gases, especially air 9, that have collected in boiler 3 below the cover 4 are also conveyed into the air trap 7 along with the transformer oil 8, thus automatically venting boiler 3. In this operating state, the connection to the fluid section of the expansion vessel 5 is prevented by the first check valve 13 located in the first line 14. From the air trap 7, the transformer oil 8 and air 9 are then conveyed through the third line 18 into the expansion vessel 5. The second check valve 17 prevents air 9 from being drawn back in. The transformer oil level in the expansion vessel 5 rises accordingly.Excess air 9 is discharged from the expansion vessel 5 into the environment via the air outlet line 12 and the vent 6 with integrated dehumidifier. When the transformer oil contained in the boiler 3 cools down again, transformer oil 8 is automatically pumped back from the expansion vessel 5 into the boiler 3 via the connecting line 15 and the first line 14, and ambient air is drawn from the environment into the expansion vessel 5 via the vent 6 with integrated dehumidifier.

[0019] Figure 2 shows a rail-bound vehicle 19 according to an embodiment of the present invention, in this case a railcar of an express train, which has a transformer 1 according to the invention.

[0020] Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples and other variations can be derived from them by a person skilled in the art without leaving the scope of protection of the invention.

[0021] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included.

Claims

Patent claims 1. Transformer (1) comprising a transformer active part (2), a tank (3) receiving the transformer active part (2) and completely filled with transformer oil (8), a cover (4) closing the tank (3), an expansion vessel (5) partially filled with transformer oil (8) and partially filled with air (9), which is arranged laterally next to the tank (3) and whose lower section, filled with transformer oil (8), is fluidically connected to the tank (3) in such a way that flow in both directions is possible, and a vent (6) with an integrated air dehumidifier, which is fluidically connected to the upper section of the expansion vessel (5), filled with air (9), characterized in that a first line (14) equipped with a first check valve (13) is provided, which fluidically connects the tank (3) to a section of the expansion vessel (5) filled with transformer oil (8),wherein the first check valve (13) allows flow exclusively through the first line (14) towards the boiler (3), and that an air trap (7) is provided above the cover (4), the lower part of which is fluidically connected to an upper part of the boiler (3) via a second line (16), and the upper part of which is fluidically connected to the expansion vessel (5) via a third line (18) equipped with a second check valve (17), in particular to a lower part of the expansion vessel (5) filled with transformer oil (8), wherein the second check valve (17) allows flow exclusively through the third line (18) towards the expansion vessel (5).

2. Transformer (1) according to claim 1, characterized in that the expansion vessel (5) has chambers (5a, 5b) has the lower areas, which are filled with transformer oil (8), each connected to each other via an oil connecting line (10), and the upper areas, which are filled with air (9), each connected to each other via an air connecting line (11).

3. Transformer (1) according to claim 2, characterized in that the chambers (5a, 5b) are positioned on opposite sides of the transformer (1).

4. Rail-bound vehicle (19) comprising a transformer (1) according to any of the preceding claims.

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