Transformer shielding with resonance-damping ground connection

Abstract

The invention relates to a transformer assembly (11). The transformer assembly (11) comprises a transformer (2) and a transformer shielding (16) for shielding the potential of a component (12, 13, 14, 15) of the transformer (2). Part of the transformer assembly (11) is also an electric connection (17) between the transformer shielding (16) and a reference potential (GND). The electric connection (17) has an impedance with a significant resonance-damping impedance value. The invention also relates to a rail vehicle (1) and to a method for installing a transformer assembly (11) in a rail vehicle (1).

Description

[0001] Description

[0002] Transformer shielding with resonance-damping earth connection

[0003] The invention relates to a transformer arrangement. Furthermore, the invention relates to a rail vehicle. Furthermore, the invention also relates to a method for installing a transformer arrangement in a rail vehicle.

[0004] Rail vehicles are equipped with transformers to convert electrical voltages. For example, a main transformer is used to step down the traction current supplied via an overhead line.

[0005] Transformers in rail vehicles may have additional shield windings or shield cylinders of various designs for various reasons. FIG. 1 shows a conventional transformer shield. The shield systems serve to deflect voltage potentials, improve or prevent transient, higher-frequency voltage transmission, or direct them into specifically designated paths. "Deflecting voltage potentials" means influencing the spatial distribution of a voltage potential in such a way that partial discharges, particularly at interfaces between different materials, are prevented or minimized, and the associated damage is also minimized.

[0006] At the same time, these measures can also have a positive or negative impact on the transformers' transmission behavior for higher-frequency interference currents. These higher-frequency interference currents can lead to limit violations both internally and externally in the infrastructure, and even cause malfunctions in signaling, communication, and safety systems in railway technology.

[0007] The reason for this is that the inductance of neighboring windings and their capacitance to these shield windings or shield cylinders can cause pronounced resonances. These resonances are caused, on the one hand, by the relatively low-impedance power windings and, on the other, by the usually intentionally low-impedance grounding of the shield winding of the shield cylinder to the transformer ground. If corresponding interference sources in these frequency ranges are also present at the same time, this can lead to significant interference levels inside and outside the rail vehicle.

[0008] The aforementioned interference signals can lead to signal disturbances in track circuits or detection circuits, which are used to monitor track sections to determine whether a rail vehicle is present in a track section or whether the track section is clear of rail vehicles and therefore a rail vehicle may enter the monitored track section. Such a scenario is illustrated in FIGS. 2 to 4.

[0009] Interference signals due to resonance effects of the shielding can also affect detection systems that operate based on the measurement of magnetic fields. Such a magnetic field is used, for example, to count the number of axles of a rail vehicle traveling through a section of track. Rail return currents also cause magnetic fields. If the frequencies of the magnetic fields are within the measuring range of the detection systems, incorrect counts can occur.

[0010] The return currents mentioned can also affect train protection systems which work together with beacons which communicate via a specific reception frequency, for example 4 MHz. One such train protection system is the ETCS (European Train Control System). A rail vehicle transmits a signal towards the track bed. Balises are arranged at predetermined intervals in the track bed which receive the signal and are activated by it. The information stored in them is then radioed back to the vehicle on a different frequency. If such communication is falsely simulated by an interference signal or if real ongoing communication is interrupted by such an interference signal, the correct monitoring of rail traffic is impaired and operations are disrupted.

[0011] One possible measure to mitigate the described difficulties is to redesign the shielding to shift resonances to non-critical frequency ranges. However, such effects are usually only discovered during an inspection of the entire rail vehicle system. Subsequent modifications are often complex and can usually only be implemented by trial and error, making the effort required to eliminate interference caused by the shielding very high.

[0012] The task is therefore to develop a transformer arrangement with a transformer shielding which immediately has a favorable resonance behavior and contributes to the reduction of interference signals and interference effects on the safety devices described above.

[0013] This object is achieved by a transformer arrangement according to patent claim 1, a rail vehicle according to patent claim 12 and a method for setting up a transformer arrangement in a rail vehicle according to patent claim 13.

[0014] The transformer arrangement according to the invention, preferably for a rail vehicle, comprises a transformer and a transformer shield for potential shielding a component of the transformer. The transformer is designed to transform an electrical alternating voltage present in the rail vehicle with a first voltage value into an electrical alternating voltage with a second voltage value. The transformer shield is designed to shield an electrical field generated by the transformer or a component of the transformer from other technical components or to define its course in such a way that interference effects based on partial discharges are reduced or minimized and associated wear is likewise reduced or minimized. Part of the transformer arrangement is also an electrical connection between the transformer shield and a reference potential.

[0015] The electrical connection has a damping function. This damping function is achieved by an impedance included in the electrical connection. The impedance has an impedance value that achieves a resonance-dampening effect, but at the same time maintains the potential shielding effect of the transformer shield. Impedance is understood to be an electrical resistance to a current, be it direct current or alternating current. "Resonance-dampening" is understood to be an impedance value that is sufficiently high to achieve sufficient resonance damping to prevent interference, and "maintaining the potential shielding effect of the transformer shield" is understood to be an impedance value that is not too high, so that the shielding retains its protective effect and no resonance occurs elsewhere.A reference potential or reference potential is a potential with a predetermined, preferably fixed value, to which all other potentials are related. Advantageously, by connecting the transformer shield to the reference potential by means of a suitably dimensioned impedance, on the one hand the desired effect of shielding, namely defining a potential in the area of ​​the shielding, is achieved and, on the other hand the undesirable occurrence of resonant oscillations in frequency ranges in which signal transmissions could be disrupted, which is observed in a conventional arrangement, is suppressed or avoided. In particular, an earth potential or a mass potential can be used as the reference potential. The rail vehicle according to the invention has the transformer arrangement according to the invention. The rail vehicle according to the invention shares the advantages of the transformer arrangement according to the invention.

[0016] In the method according to the invention for setting up a transformer arrangement in a rail vehicle, a transformer is installed in the rail vehicle. Furthermore, a transformer shield is set up for potential shielding a component of the transformer. Finally, an electrical connection is formed between the transformer shield and a reference potential. The electrical connection is formed with an impedance with a resonance-dampening impedance value that maintains the effect of the potential shielding of the transformer shield. An embodiment of the method according to the invention enables the production of a transformer arrangement with the advantages of the transformer arrangement according to the invention.

[0017] The dependent claims and the following description each contain particularly advantageous embodiments and developments of the invention. In particular, the claims of one claim category can also be developed analogously to the dependent claims of another claim category and their description parts. Furthermore, within the scope of the invention, the various features of different embodiments and claims can also be combined to form new embodiments.

[0018] The electrical connection of the transformer arrangement according to the invention preferably comprises a complex impedance. A complex impedance allows alternating currents and the resulting magnetic or electromagnetic fields to be attenuated.

[0019] Most preferably, the electrical connection of the transformer arrangement according to the invention comprises an impedance formed by an impedance unit comprising at least one damping element with a frequency-dependent damping behavior, preferably a plurality of parallel-arranged damping elements with different frequency-dependent damping behavior. Advantageously, individual, particularly critical frequency ranges can be specifically subjected to damping. A particularly "critical" frequency range is understood to mean one in which currents and / or signals with a relevant function for rail traffic, in particular a safety function, occur.

[0020] Thus, the impedance unit of the transformer arrangement according to the invention preferably comprises at least one damping element, preferably a plurality of damping elements, each of which is designed to dampen interference currents in the aforementioned critical frequency ranges.

[0021] The critical frequency ranges mentioned preferably include at least one of the following frequency ranges:

[0022] - a low frequency range which is susceptible to track circuit interference,

[0023] - a medium frequency range that is susceptible to axle counter interference, and

[0024] - a high frequency range which is susceptible to balise device interference.

[0025] Attenuation in the low-frequency range is required to prevent interference with railway signaling equipment. Attenuation in the medium-frequency range is required to prevent interference with vehicle detection equipment. Furthermore, attenuation in the high-frequency range is required to prevent interference with the exchange of information between a rail vehicle and the infrastructure via balises.

[0026] Alternatively, the electrical connection of the transformer arrangement according to the invention comprises an impedance that includes only one damping element with a frequency-dependent damping behavior. Advantageously, a single, particularly critical frequency range can be specifically subjected to damping. As already mentioned, a frequency range in which currents and / or signals with a relevant function for rail traffic, in particular a safety function, occur can be understood as particularly "critical."

[0027] Therefore, the impedance unit of the transformer arrangement according to the invention preferably comprises a damping element designed to dampen interference currents in the aforementioned critical frequency range. As already mentioned, such a critical frequency range can comprise a low-frequency range, a medium-frequency range, or a high-frequency range.

[0028] The reference potential preferably comprises a ground potential or earth potential. Advantageously, the reference potential can be generated and maintained passively.

[0029] Particularly preferably, the electrical connection comprises an electrical connection which is formed to an internal, conductive component. An "internal, conductive component" is to be understood as a component which implements an electrical connection of the transformer shield to a component within a housing, preferably a transformer tank or transformer vessel. The transformer arrangement according to the invention preferably comprises such a housing, particularly preferably a transformer tank or transformer vessel.

[0030] A solution with an internal conductive component has the advantage that any power loss from this component occurs in the cooling area of ​​the transformer. A transformer usually has its own cooling system or cooling unit, preferably an oil cooling unit, which can be used by the internal conductive component. Furthermore, because of this external cooling, the component does not need such a large surface area to cool itself. The transformer arrangement according to the invention therefore preferably comprises such a cooling unit within the housing, with which both the transformer windings and the described electrical connection can advantageously be cooled, so that temperature-related failure or wear of the aforementioned technical components does not occur.

[0031] In one embodiment of the transformer arrangement according to the invention, the internal conductive component comprises one of the following elements:

[0032] - the inside of a transformer tank or transformer vessel in which the transformer assembly is located,

[0033] - a core sheet of the transformer assembly

[0034] - an adjacent winding of the transformer assembly.

[0035] A transformer tank, also called a tank, is a steel structure that encloses the active part, in particular the transformer core and the windings of a transformer, and is closed by a cover. The magnetic fields of the windings and conductors cause eddy current losses in the steel parts of the transformer tank. In order to limit these losses and reduce the heating of the steel parts, the steel parts can be partially shielded against higher-frequency magnetic fields using the transformer shielding mentioned above. There are also numerous add-on parts, such as the piping of an expansion tank or domes of bushings. Furthermore, the transformer tank is filled with oil under vacuum. The transformer tank itself has a particularly pronounced shielding effect.

[0036] A core sheet is used to form a transformer core. Using such a core sheet instead of a solid material enables the suppression or reduction of eddy currents, which would otherwise increase with increasing frequency and contribute to significant heating of the transformer core and thus to high power loss. Therefore, transformer cores are constructed from laminated and insulated sheets in stack form or as wound cut-core cores.

[0037] Alternatively or additionally, the electrical connection of the transformer arrangement according to the invention comprises an electrical connection to an external component. An "external component" is understood to mean a component outside the housing of the transformer arrangement, preferably outside the transformer tank or the transformer vessel. Advantageously, an external component is easily accessible and can therefore be easily maintained or modified.

[0038] The external component of the electrical connection of the transformer arrangement according to the invention preferably comprises an externally mounted earthing terminal or ground connection for providing the reference potential, which is arranged outside the transformer or outside the transformer tank. Advantageously, a direct electrical connection of the shielding to the earthing terminal or ground connection is achieved via the impedance.

[0039] The invention is explained in more detail below with reference to the accompanying figures using exemplary embodiments. They show:

[0040] FIG 1 is a schematic diagram of a transformer with a conventional transformer shield,

[0041] FIG 2 a schematic representation of a track current measurement between a generator and a motor relay,

[0042] FIG 3 is a schematic representation of a detection of a rail vehicle in a track section, FIG 4 is a schematic representation of a scenario in which an interference current is generated by a rail vehicle,

[0043] FIG 5 is a schematic representation of a transformer arrangement according to an embodiment of the invention,

[0044] FIG 6 is a schematic representation of a transformer arrangement according to an alternative embodiment of the invention,

[0045] FIG 7 is a flowchart illustrating a method for setting up a transformer arrangement in a rail vehicle according to an embodiment of the invention,

[0046] FIG 8 shows a rail vehicle with a transformer arrangement according to an embodiment of the invention,

[0047] FIG 9 an impedance unit with a plurality of damping components with different damping properties,

[0048] FIG 10 is a diagram illustrating a frequency-dependent transmission ratio of a transformer.

[0049] FIG. 1 shows a schematic representation of a transformer 2 with conventional shielding. The transformer 2 comprises a transformer core 12 at its center. A first low-voltage winding 13 is located around the transformer core 12. High-voltage windings 14 in several layers are arranged around the first low-voltage winding 13. Three layers are shown in FIG. 1 as an example. A second low-voltage winding 15 is arranged around the high-voltage windings 14. Optional protective windings or protective shields 16, also referred to as transformer shields, are arranged between the individual windings 13, 14, 15. The protective shields mentioned are conventionally without exception connected to the tank ground or hard-grounded without additional impedance. FIG. 2 shows a schematic representation, i.e.a plan view of an unoccupied section of track 10 with track monitoring with a track current measurement between a generator 6 and a motor relay 8. The track current measurement is used to determine whether the section of track 10 is free of a rail vehicle 1 (therefore only shown in FIG 3) or occupied. This is intended to avoid a collision between two rail vehicles traveling on the same track or the same rails 7a, 7b. The generator 6 shown in FIG 2 on the bottom left generates two electrical voltages that are 90° out of phase, one of which is conducted between the rails, i.e. the insulated rail 7a and the earth rail 7b of the section of track 10, and the other is conducted via a power line 6a to the motor relay 8, which is shown in FIG 2 on the bottom right. The motor relay 8 is held in a rest position by spring force.The two electrical voltages generate a rotating field and thus a torque. Therefore, when a track section 10 is unoccupied, the motor relay 8 rotates to the operating position, and the track section 10 is recognized as unoccupied.

[0050] FIG. 3 shows the track section 10 already shown in FIG. 2 in a situation in which a rail vehicle 1 is located on the monitored track section 10. The rail vehicle 1 short-circuits the track voltage present between the rails 7a, 7b with its chassis, so that the rotating field in the motor relay 8 disappears. The spring pulls the motor relay 8 into the rest position, and the track section 10 is thus detected and reported as occupied.

[0051] However, the return current of an electric rail vehicle 1 can interfere with the track clearance signal, i.e., act as a disturbance current, if this current at the measuring point, i.e., at the position of the motor relay 8, exactly corresponds to the fed-in current, i.e., the current measured in the case of the clear track section. For this to happen, a response threshold must be exceeded at the operating frequency of the motor relay 8, and this exceedance must persist long enough for the motor relay 8 to respond, and the response to be registered in the interlocking system.

[0052] FIG. 4 shows a schematic representation of a scenario in which such an interference current is generated by a rail vehicle 1. A current flows from an overhead line OL via an interference current monitoring unit DSU to the electrical components (not shown) of the rail vehicle 1. Furthermore, the two rails 7a, 7b are short-circuited via the chassis of the rail vehicle 1, and a reverse current flows to the motor relay 8.

[0053] In this case, the return current must not exceed a predetermined limit value of a current intensity for a time which is longer than a predetermined period of time in a predetermined frequency range in which the frequency of the electrical voltage generated by the generator 6 lies, for example 42 Hz. Typical values ​​are 42 Hz + / - 2 Hz for the frequency range, 2.8 amperes for the limit value of the current intensity and 0.5 s for the predetermined period of time. The frequencies of such a return current are determined by the power converters in the vehicle. Their amplitudes, however, are significantly influenced by, among other things, resonance effects which are generated by shielding and shield connections.

[0054] FIG. 5 shows a transformer arrangement 11 with a protective shield 16 with internal connection according to an exemplary embodiment of the invention. For the sake of simplicity, FIG. 5 only shows a section of a transformer arrangement 1 with only one protective shield 16. The transformer arrangement can have the shape shown in FIG. 1. In addition, the transformer arrangement 11 shown in FIG. 5 comprises an internal connection of the protective shield 16 to a protective earth GND. With such an internal connection, the protective shield 16 is electrically connected to a transformer tank 18 via an impedance 17 instead of a direct hard earthing. The transformer tank 18 itself is electrically connected to the protective earth GND. The impedance can optionally be designed as a real-valued electrical resistance, which is symbolized by "R" in FIG. 5, or as a complex electrical resistance, which is symbolized by "Z" in FIG. 5.

[0055] 6 shows a transformer arrangement 1 with a protective shield 16 with external connection according to an exemplary embodiment of the invention. For the sake of simplicity, FIG. 6 again shows only a section of a transformer arrangement 11 with only one protective shield 16. The transformer arrangement 11 can have the shape shown in FIG. 1. In addition, the transformer arrangement 11 shown in FIG. 6 comprises an external connection of the protective shield 16 to a protective earth GND. The protective shield 16 is led out of the transformer tank 18 via an insulated electrical line 17a. The transformer tank 18 is directly electrically connected to earth GND. The insulated line 17a is electrically connected to earth GND via an optional impedance 17 which lies outside the transformer tank 18.This impedance 17 can optionally be designed as a real-valued electrical resistance, which is symbolized by “R” in FIG. 6, or as a complex electrical resistance, which is symbolized by “Z” in FIG. 6.

[0056] FIG 7 shows a flow chart 700 which illustrates a method for setting up a transformer arrangement 11 in a rail vehicle 1.

[0057] In step 7 . 1 , a transformer 2 is first installed as part of the power electronics in the rail vehicle 1 .

[0058] In step 7.II, a transformer shield 16 is further set up for potential shielding 16 of a component 12, 13, 14, 15 of the transformer 2. For example, shields 16 are formed between the transformer core 12 and a first low-voltage winding 13, between the first low-voltage winding 13 and high-voltage windings 14 of the transformer 2, and between the individual high-voltage windings 14. Further shields 16 can be arranged between the high-voltage windings 14 and a second outer low-voltage winding 15 and externally around the second low-voltage winding 15 of the transformer 2.

[0059] Finally, in step 7.III, an electrical connection 17 is formed between the transformer shield 16 and a reference potential GND with an impedance having a resonance-damping impedance value that maintains the effect of the potential shielding of the transformer shield 17.

[0060] FIG 8 shows a schematic representation of an electrified rail vehicle 1 with a transformer arrangement 11 according to an embodiment of the invention. The electrified rail vehicle 1, in this case a rail vehicle 1 exclusively for operation with alternating voltage, comprises a pantograph 22 for supplying electrical energy from a traction current network N, in this case an alternating voltage traction current network, which is electrically connected to a primary current transformer PW via a main switch 23. The primary current transformer PW converts the alternating current in the ranges from 100 to 1200 A into smaller currents. A disturbance current monitoring unit DSU is connected downstream of the primary current transformer PW. Such a disturbance current monitoring unit DSU measures disturbance currents in the ranges of a few milliamperes.Connected downstream of the interference current monitoring unit DSU is a transformer arrangement 11 according to the invention, in this exemplary embodiment a transformer arrangement comprising the main transformer, which transforms down the high voltage supplied by the traction power network N. Electrically connected to the main transformer or the transformer arrangement 11 are two converters 26, which convert the alternating current into direct current.

[0061] FIG 9 shows an impedance unit 34 with a plurality of damping components with different damping properties.

[0062] A transformer has transmission ratios that vary depending on the frequency, which can cause problems with various types of signaling and safety equipment inside and outside a rail vehicle.

[0063] The impedance unit 34 has a total of five damping elements 35, 36, 37, 38, 39 connected in parallel for damping different frequency ranges. A first damping element 35, shown on the left in the figure, has a resonant circuit with a first capacitance Gl and a first inductance LI for selecting a first frequency range f1 (see FIG. 10), as well as a first electrical resistance RI for damping. A second damping element 36, shown to the right of the first damping element 35, has a resonant circuit with a second capacitance C2 and a second inductance L2 for selecting a second frequency range f2 (see FIG. 10), as well as a second electrical resistance R2 for damping.A third damping element 37, shown to the right of the second damping element 36, has a resonant circuit with a third capacitance C3 and a third inductance L3 for selecting a third frequency range f3, as well as a third electrical resistor R3 for damping. A fourth damping element 38, shown to the right of the third damping element 37, has a fourth resistor R4 for damping high-frequency currents, which is connected in series with a fourth capacitance C4.

[0064] A fifth damping element 39 shown to the right of the fourth damping element 38 has a fifth resistor R5 for the damping of low-frequency currents, wherein a fourth inductance L4 is connected in series with the fifth resistor R5.

[0065] A diagram of the frequency-dependent transmission ratio of a common transformer is shown as an example in FIG 10.

[0066] It is the ratio, i.e. the transmission ratio T of the secondary voltage of the transformer to the primary short-circuit current on the ordinate in kOhm plotted against the respective frequency f in kHz on the abscissa. The transmission ratio T can be roughly divided into three different frequency ranges, as shown in FIG 10 by the reference numerals fl, f2, f3. The low-frequency range fl is susceptible to track circuit interference, the medium-frequency range f2 is susceptible to axle counter interference, and the high-frequency range f3 is susceptible to balise device interference. Attenuation in the low-frequency range fl is required to prevent interference with railway signaling equipment. Attenuation in the medium-frequency range f2 is required to prevent interference with vehicle detection equipment.Attenuation in the high frequency range f3 is required to avoid interference with the information exchange between a rail vehicle and the infrastructure via balises.

[0067] Not every one of the mentioned frequency ranges fl, f2, f3 may be affected by disturbing resonances resulting from a particular transformer design, since this depends on the resonance frequency and the natural damping by the transformer itself.

[0068] As already mentioned, FIG 9 shows different variants of damping elements 35, 36, 37, 38, 39 for damping the resonances illustrated in FIG 10. Full broadband damping with a simple resistor R may be possible. However, more complex, frequency-selective substructures may also be necessary. Such an impedance unit 34 with a plurality of damping components is shown in FIG 9. The use of such a complex impedance unit 34 may be necessary because damping in a certain frequency range may amplify problems in other frequency ranges. However, it may also be the case that damping at low frequencies requires a very robust electrical resistor for a high load (high current, high losses), which is not necessary at higher frequency ranges.At the same time, such high-power resistors may generally not be sufficient for higher frequencies because their own parasitic inductive or capacitive behavior is unsuitable.

[0069] Finally, it is pointed out once again that the methods and devices described above are merely preferred embodiments of the invention and that the invention can be varied by a person skilled in the art without departing from the scope of the invention, insofar as it is defined by the claims. For the sake of completeness, it is also pointed out that the use of the indefinite articles "a" or "an" does not exclude the possibility that the features in question may be present in multiple copies. Likewise, the term "unit" does not exclude the possibility that this may consist of several components, which may also be spatially distributed. Regardless of the grammatical gender of a particular term, persons with male, female or other gender identity are included.

Claims

Patent claims 1. Transformer arrangement (11) comprising: - a transformer (2) , - a transformer shield (16) for potential shielding of a component (12, 13, 14, 15) of the transformer (2), - an electrical connection (17) between the transformer shield (16) and a reference potential (GND), wherein the electrical connection (17) has an impedance with a resonance-damping impedance value maintaining the effect of the potential shielding of the transformer shield (16).

2. Transformer arrangement (11) according to claim 1, wherein the electrical connection (17) comprises a real-valued impedance.

3. Transformer arrangement according to claim 1 or 2, wherein the electrical connection (17) comprises a complex-valued impedance.

4. Transformer assembly according to one of the preceding claims, wherein the electrical connection (17) comprises an electrical connection to an internal conductive component (18).

5. Transformer assembly according to claim 4, wherein the internal conductive component (18) comprises one of the following elements: - the inside of a transformer tank or transformer vessel, - a core sheet - an adjacent winding.

6. Transformer arrangement according to one of the preceding claims, comprising a cooling unit for cooling the transformer (2).

7. Transformer arrangement according to one of the preceding claims, wherein the electrical connection (17) comprises an electrical connection to an external component.

8. Transformer arrangement according to claim 7, wherein the external component comprises an externally mounted ground terminal (GND) which is arranged outside the transformer (2).

9. Transformer arrangement according to one of the preceding claims, wherein the impedance comprises an impedance unit (34) which comprises a plurality of parallel-arranged damping elements (35, 36, 37, 38, 39) with different frequency-dependent damping behavior.

10. Transformer arrangement according to claim 9, wherein the frequency-dependent damping behavior of the damping elements (35, 36, 37, 38, 39) is designed such that interference currents with frequencies in particularly interference-critical frequency ranges (f1, f2, f3) are damped.

11. Transformer arrangement according to claim 10, wherein the particularly interference-critical frequency ranges (f1, f2, f3) comprise at least one of the following frequency ranges: - a low frequency range (fl) which is susceptible to track circuit disturbances, - a medium frequency range (f2) which is susceptible to axle counter interference, and - a high frequency range (f3) which is susceptible to balise device interference.

12. Rail vehicle (1) comprising a transformer arrangement (11) according to one of claims 1 to 11.

13. Method for setting up a transformer arrangement (11) in a rail vehicle (1), comprising the steps: - installing a transformer (2) in the rail vehicle (1), - Setting up a transformer shield (16) for potential shielding of a component (12, 13, 14, 15) of the transformer (2), - forming an electrical connection (17) between the transformer shield (16) and a reference potential (GND) with an impedance having a resonance-damping impedance value that maintains the effect of the potential shielding of the transformer shield (16).

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