Choke and testing equipment for performing high voltage tests

Abstract

A choke (D) for performing a high voltage test, the choke comprising: a housing (G); a coil (S) arranged inside the housing (G); at least one conductive member; and a magnetic conductive device (FF), the magnetic conductive device guiding a magnetic flux that can be generated by means of the coil (S). The conductive member is arranged between the coil (S) and the housing (G). The magnetic conductive device (FF) comprises a ferromagnetic material and is arranged between the coil (S) and the at least one conductive member, so that the magnetic flux that can be generated by means of the coil (S) is guided to pass by the conductive member or is substantially guided to pass by the conductive member.

Description

Technical Field

[0001] The invention relates to a choke for carrying out high-voltage tests on a test object and to a testing device having at least one such choke. Background Art

[0002] High-voltage installations and high-voltage components are capacitive test objects. These capacitive test objects are connected to one or more chokes for high-voltage testing to form a resonant circuit, which is supplied with a variable frequency, for example, by feeding. Here, for example, chokes with air-core coils are used, which are arranged in a metal container. In such chokes, an uncontrolled distribution of the magnetic flux occurs, which leads to increased eddy current losses not only in the metal container but also in the conductive components of the choke inside the metal container. Due to these eddy current losses, the performance of the resonant circuit is reduced. Summary of the invention

[0003] It is therefore an object of the present invention to specify an improved concept for a choke for carrying out high-voltage tests, by which eddy current losses are reduced.

[0004] The improved concept is based on the idea of ​​providing a ferromagnetic material as a magnetic conductor within the choke, via which the magnetic flux is guided past the electrically conductive components which could otherwise be a source of increased turbine losses.

[0005] According to the improved solution, a choke for performing a high voltage test is provided, the choke having: a housing; a coil arranged inside the housing; at least one conductive component; and a magnetic conductive device for guiding a magnetic flux that can be generated by means of the coil. The conductive component is arranged between the coil and the housing. The magnetic conductive device includes a ferromagnetic material and is arranged between the coil and the at least one conductive component, so that the magnetic flux that can be generated by means of the coil is guided to pass by the conductive component or is guided to pass substantially by the conductive component.

[0006] Here, the magnetic flux being guided past the conductive component or being guided substantially past the conductive component should be understood as: eliminating or reducing the magnetic flux passing through the conductive component. This is achieved in particular by arranging the magnetic conductive device between the coil and the conductive component. As a result, eddy currents and corresponding eddy current losses in the conductive component are prevented or reduced. If the choke is used as a component of a resonant circuit in a test device, this ultimately leads to improved performance of the resonant circuit. As a result, the power supplied to the test device can be reduced. At the same time, by using ferromagnetic materials, the inductance of the choke is increased, so that the structural size of the choke can be reduced at the same inductance or the working capacity of the choke can be increased at the same structural size.

[0007] According to at least one embodiment, the ferromagnetic material of the magnetic conductive device or individual components of the magnetic conductive device include a magnetic steel sheet or a stack of magnetic steel sheets or a magnetic steel strip material or an amorphous ferromagnetic material.

[0008] According to at least one embodiment, the housing at least partially comprises an electrically conductive material, for example metal. The magnetic conductor is arranged such that it shields the electrically conductive material of the housing from a magnetic flux that can be generated by means of the coil.

[0009] According to at least one embodiment, the housing at least partially comprises steel. For example, a housing wall of the housing can be composed entirely of steel.

[0010] By shielding the housing from the magnetic flux, eddy current losses in the housing are reduced. This makes it possible to dispense with costly materials with particularly high electrical conductivity, such as aluminum, and to use cost-effective materials, such as steel, instead. The wall thickness of the housing material can also be reduced without the thermal effects caused by eddy current losses exceeding a technically acceptable level.

[0011] According to at least one embodiment, the magnetic conductive device comprises a cylindrical, in particular a circular cylindrical component, which at least partially surrounds the coil in the radial direction. Here, "encircling in the radial direction" means encircling in a plane perpendicular to the winding axis of the coil. In the axial direction, i.e. parallel to the winding axis, the coil can extend beyond the cylindrical component or end at the cylindrical component. Alternatively, the cylindrical component can extend beyond the coil in the axial direction.

[0012] According to at least one embodiment, the cylindrical component completely surrounds the coil in radial direction.

[0013] According to at least one embodiment, the cylindrical component at least partially comprises a ferromagnetic material.

[0014] According to at least one embodiment, the magnetic conductor comprises at least two sections, which are distributed around the coil in the radial direction, for example, evenly distributed, and extend along the coil in the axial direction, for example, completely or substantially completely along the coil. The number and size of the sections can be such that the sections together completely or partially surround the coil in the radial direction.

[0015] According to at least one embodiment, the segments are designed in the form of rods or cubes or as segments of a hollow cylinder, in particular a hollow circular cylinder.

[0016] According to at least one embodiment, the sections each at least partially consist of a ferromagnetic material.

[0017] According to at least one embodiment, the magnetic conductive device is electrically and mechanically connected to the coil, so that the magnetic conductive device and the coil are at the same potential.

[0018] According to at least one embodiment, the housing is electrically insulated from the magnetic conductor and from the coil.

[0019] According to at least one embodiment, the magnetic conductor or the cylindrical component or the segments are carried by the coil and / or lie flat on the coil. This achieves a particularly compact design of the choke.

[0020] According to at least one embodiment, the magnetic conductor or the cylindrical component or the segments are connected to the coil by means of an adjustment screw, in particular, a gap between the magnetic conductor or the cylindrical component or the segment and the coil can be achieved thereby to compensate for tolerances caused by manufacturing.

[0021] According to at least one embodiment, the at least one electrical component comprises at least one field control electrode.

[0022] During the high-voltage test, the housing and the magnetic conductor are at different potentials. Accordingly, the field control electrode is a shield that is used to prevent the highest field strengths from occurring at corners, edges or surfaces with small radii of curvature and thus reduce the required spark distance within the choke, in particular the required distance between the coil and the housing or between the magnetic conductor and the housing.

[0023] According to at least one embodiment, the electrically conductive component or the field control electrode is arranged between the magnetic conductor and the housing, in particular radially between the magnetic conductor and the housing.

[0024] According to at least one embodiment, the field control electrodes are arranged at the end faces of the cylindrical component or of the segments.

[0025] According to at least one embodiment, the at least one electrical component comprises one or more further field control electrodes.

[0026] According to at least one embodiment, one of the further field control electrodes is arranged at the other end-side end of the cylindrical component or of the segments.

[0027] According to at least one embodiment, the field control electrode has an annular structure and is oriented coaxially with respect to the winding axis of the coil.

[0028] According to at least one embodiment, the field control electrode consists partially or completely of metal. In particular, the field control electrode comprises a metal body. In particular, the field control electrode does not consist of an electrical insulator having an electrically conductive coating.

[0029] By guiding the magnetic flux past the field control electrode by means of a magnetic conductor and thereby reducing the eddy currents in the field control electrode, a construction with a metal body can be used. On the one hand, this has cost advantages compared to the use of a plastic body with a conductive coating, for example a coating consisting of a semiconductor material. In addition, the field control electrode with a metal body can have a surface with lower roughness, for example a polished surface, and can therefore lead to lower maximum field strengths. As a result, the required spark distance inside the choke is reduced and a more compact design can therefore be achieved.

[0030] According to at least one embodiment, the choke comprises a suspension, in particular a central suspension, which carries the coil.

[0031] According to at least one embodiment, the suspension device consists of an electrically non-conductive material.

[0032] According to at least one embodiment, the suspension device is aligned coaxially with respect to the winding axis of the coil.

[0033] According to at least one embodiment, the suspension device comprises one or more supporting bodies which are mechanically connected to one another.

[0034] According to at least one embodiment, the magnetic conductive device comprises an inner component, which is arranged inside the suspension device. In particular, the inner component is at least partially composed of a ferromagnetic material. As a result, the inductance of the choke is further increased.

[0035] According to at least one embodiment, the magnetic conductive device comprises at least one end side component, which is arranged at the end side of the coil and is oriented perpendicular to the winding axis of the coil. The end side component is especially at least partially composed of ferromagnetic material. As a result, the part of the housing located at the end side of the coil or the correspondingly arranged conductive component of the choke shields the magnetic flux.

[0036] According to at least one embodiment, the end part is connected to the cylindrical part or to at least one of the sections.

[0037] According to at least one embodiment, the choke comprises at least one further coil which is connected in series with the coil.

[0038] According to at least one embodiment, the coil and the at least one further component have a common winding axis and are arranged axially next to one another or radially overlapping, in particular on a suspension device.

[0039] According to at least one embodiment, the coil is designed as an air-core coil, i.e., as a coil without a ferromagnetic core. If the choke comprises a further coil axially adjacent to the coil, the further coil is also designed as an air-core coil. The term "air-core coil" does not exclude that, instead of or in addition to air, non-ferromagnetic material, in particular an insulating medium, is present in the housing and inside the coil.

[0040] The coil and the further coil can be wound, for example, in such a way that axially adjacent coils have different potentials, in particular high voltage potentials, on their radial inner sides. The coils are therefore spaced correspondingly apart from one another in the axial direction in order to ensure the required electrical breakdown strength. By being configured as air-core coils, it is ensured that the distance is not bridged.

[0041] According to at least one embodiment, the choke has a high-voltage connection for electrical contacting of the coil, in particular the first contact of the coil. Here, the high-voltage connection can be used, for example, to connect a test piece.

[0042] According to at least one embodiment, the high voltage connection terminal includes a high voltage lead.

[0043] According to at least one embodiment, the choke has a further voltage connection, in particular a further high-voltage connection, which comprises a lead, in particular a further high-voltage lead.

[0044] In at least one embodiment of the choke in which the choke has only one coil, the further voltage connection is provided for electrical connection to a second contact of the coil.

[0045] In at least one embodiment of the choke having the coil and the further coil, the further voltage terminal serves for electrical connection to the further coil.

[0046] According to at least one embodiment, the suspension device is fastened to the high-voltage conductor and / or to the further conductor.

[0047] According to at least one embodiment, the high-voltage conductor and the further conductor are arranged on opposite sides of the housing.

[0048] According to at least one embodiment, the choke is designed as a choke with a fixed inductance, in particular a choke with an inductance that cannot be varied.

[0049] According to at least one embodiment, the interior of the housing is filled with an insulating medium, in particular a non-conductive fluid, such as an insulating liquid or an insulating gas.

[0050] According to at least one embodiment, the insulating medium is at a pressure that is elevated relative to the ambient pressure. As a result, the required spark distance can be reduced, which contributes to a more compact design.

[0051] According to this improved concept, a test device for carrying out a high-voltage test on a test object is also provided. The test device has a choke according to the improved concept.

[0052] According to at least one embodiment, the housing of the choke is grounded.

[0053] According to at least one embodiment, the test device comprises a power supply which is connected or connectable to the choke and the test piece to form a resonant circuit. In this case, the choke is arranged between the power supply and the test piece. In particular, the high-voltage connection is connected or connectable to the test piece, and the further voltage connection is connected or connectable to the power supply.

[0054] According to at least one embodiment, the feed current source is designed as a variable-frequency voltage source.

[0055] According to at least one embodiment, the test device has one or more further chokes which are connected in series or in parallel with the choke. In this embodiment, the further voltage connection of the choke is connected or connectable to a feed source directly or via a further choke. The further choke or some of the further chokes can be designed according to this improved concept.

[0056] According to at least one embodiment, the test device comprises a test piece.

[0057] According to at least one embodiment, the resonant circuit is a series resonant circuit or a parallel resonant circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In the following, the invention is explained in detail with reference to the accompanying drawings based on exemplary embodiments. Components with the same function or the same effect may be provided with the same reference numerals. Identical components or components with the same function are explained in particular only with respect to the drawing in which they first appear. The explanation does not necessarily have to be repeated in the following drawings.

[0059] Here, it is shown that:

[0060] Figure 1 A block circuit diagram of an exemplary embodiment of a test device having a choke according to the improved concept is shown;

[0061] Figure 2 A cross-sectional view of an exemplary embodiment of a choke according to the improved solution is shown; and

[0062] Figure 3 A sectional view shows another exemplary embodiment of a choke according to this improvement. DETAILED DESCRIPTION

[0063] Figure 1 A block circuit diagram shows an exemplary embodiment of a test device having a choke, in particular a series resonant circuit, according to the improved concept.

[0064] The test device comprises: a feed source EQ, which is designed as an AC voltage source; a choke D according to the improved solution; and a test piece P having a test piece capacitance connected in series with the choke D. Optionally, in the resonant circuit, one or more further test chokes can be connected in series and / or in series with the choke D, which are designed, for example, identically to the choke D. Furthermore, the resonant circuit can comprise further components, not shown.

[0065] The feed source EQ is connected, for example, to the coil of the choke D. During operation, an excitation voltage, in particular an AC voltage, is provided by the feed source EQ, which is present at the choke D and the test piece P. In the case of resonance, a test voltage which is greater in value than the excitation voltage is present at the test piece P, so that an overvoltage occurs. The performance of the resonant circuit, i.e. the ratio of the test reactive power to the power loss of the resonant circuit, corresponds to the ratio of the test voltage to the excitation voltage.

[0066] Now, different embodiments of the choke D are described with respect to Figure 2 and Figure 3 Described in more detail.

[0067] Figure 2 An exemplary embodiment of a choke according to an improved concept is shown.

[0068] The choke has a housing G which is at least partially made of metal, for example steel. In the resonant circuit, the housing is grounded, for example. The choke has a central suspension device A, around which the coil S is arranged. The choke also has a first and a second lead DF1, DF2, wherein at least the first lead DF1 is designed as a high-voltage lead. The first lead DF1 is used, for example, for connection to a Figure 1 The second lead DF2 is used, for example, to connect to the test piece P in the device shown in FIG. Figure 1 The feed source EQ in an arrangement such as that shown in FIG. 1 or for connecting another choke (not shown). The suspension device is fixed, for example, to the housing G and / or to one or two leads DF1 , DF2 .

[0069] The choke has a magnetic conductor FF for conducting the magnetic flux that can be generated by means of the coil S. The magnetic conductor FF contains a ferromagnetic material or consists of a ferromagnetic material. In the example depicted, the magnetic conductor FF consists of a cylindrical component that completely surrounds the coil S in the radial direction or consists of a plurality of segments, for example four segments, that partially or completely surround the coil S in the radial direction.

[0070] Furthermore, the choke has, for example, two field control electrodes F1, F2, which are each arranged on the end side of the cylindrical part between the magnetic conductor FF and the housing G. The field control electrodes F1, F2 are, for example, annular in shape and surround the cylindrical part in the radial direction. The field control electrodes F1, F2 serve to shield or avoid the highest field strengths between the magnetic conductor FF and the housing G. Without the field control electrodes, the distance between the housing G and the magnetic conductor FF must be increased in order to reliably prevent discharges.

[0071] The cylindrical part or the section of the magnetic conductor FF is arranged between the coil S and the field control electrodes F1, F2. Therefore, the leakage flux through the housing G and through the field control electrodes F1, F2 is reduced or prevented by the magnetic conductor FF. The eddy currents in the housing G and the field control electrodes F1, F2 are reduced by the magnetic flux controlled in this way. With this construction, it becomes possible to equip the compact choke with a steel housing, for example. The field control electrodes F1, F2 can also be made entirely or partially of metal, and do not need to be produced in a complex manner from plastic with a conductive coating.

[0072] Figure 3 A further exemplary embodiment of a choke according to an improved concept is shown. Figure 3 The implementation method is Figure 2 implementation method based on.

[0073] Different from Figure 2 In the implementation method, Figure 3 The choke in the embodiment has two series-connected coils S1 and S2 instead of the coil S, which are arranged axially side by side on the suspension device A. In other words, a coil having two series-connected sub-windings S1 and S2 is used. In an alternative embodiment, the two coils S1 and S2 can be arranged radially overlapping.

[0074] Optionally, a further field control electrode FW is provided, which is arranged between the ends of the coils S1, S2 facing each other, in order to reduce the maximum electric field strength between the two coils S1, S2 and thus to reduce the distance between the two coils, which contributes to a compact design. The further field control electrode FW is designed, for example, in annular form and surrounds the suspension device A in the radial direction.

[0075] By means of a choke according to the improved scheme, eddy current losses in the choke housing and in the conductive components of the choke are reduced. In particular, cost-effective materials can be used for the housing or the conductive components and a particularly compact design of the choke can be achieved, since a higher resistance of the housing or the conductive components is less important due to the reduced eddy current losses. Correspondingly, a more powerful choke can be manufactured for the same structural dimensions. Due to the lower eddy current losses, the performance of the resonant circuit using the choke is improved. This reduces the power demand of the feed. Due to the reduced power of the feed, other components integrated in the test device can be reduced in terms of their power and structural dimensions.

[0076] Reference numerals

[0077] D Choke

[0078] P test piece

[0079] EQ Feeder

[0080] G housing

[0081] A Suspension

[0082] FF magnetic device

[0083] S, S1, S2 coils

[0084] F1, F2, FW field control electrodes

[0085] DF1, DF2 leads

Claims

1. A choke for performing a high voltage test, the choke comprising: - housing (G); - a coil (S) arranged inside the housing (G); - at least one electrically conductive member arranged between the coil (S) and the housing, said at least one electrically conductive member comprising a field control electrode (F1 , F2); and - a magnetic conductor (FF) for conducting a magnetic flux that can be generated by means of a coil (S), wherein the magnetic conductor (FF) - contains ferromagnetic material; and - is arranged between the coil (S) and the at least one electrically conductive component, such that the magnetic flux that can be generated by means of the coil (S) is guided past the electrically conductive component.

2. The choke according to claim 1, wherein: The housing (G) at least partially comprises an electrically conductive material, and the magnetically conductive device (FF) is arranged such that it shields the electrically conductive material of the housing (G) from a magnetic flux that can be generated by means of the coil (S).

3. The choke according to claim 1 or 2, wherein: The magnetic conductive device (FF) comprises a cylindrical component which at least partially surrounds the coil (S) in a radial direction.

4. The choke according to claim 1 or 2, wherein: The magnetic conductive device (FF) comprises at least two sections, which are arranged to be distributed around the coil (S) in a radial direction and extend along the coil (S).

5. The choke according to claim 1 or 2, wherein: The magnetic conductive device (FF) is electrically and mechanically connected to the coil (S).

6. The choke according to claim 1 or 2, wherein: The conductive member is arranged between the magnetic conductive device (FF) and the housing (G).

7. The choke according to claim 6, wherein: The conductive member is arranged between the magnetic conductive device (FF) and the housing (G) in the radial direction.

8. The choke according to claim 1 or 2, wherein: The coil (S) is designed as an air-core coil.

9. The choke according to claim 1 or 2, wherein: The choke (D) comprises a suspension device (A) which carries the coil (S), and the magnetic conductive device (FF) comprises an internal component which is arranged inside the suspension device (A).

10. The choke according to claim 1 or 2, wherein: The magnetic conductor (FF) comprises at least one end part which is arranged at an end end of the coil (S) and is oriented perpendicularly to a winding axis of the coil (S).

11. The choke according to claim 1 or 2, wherein: The choke (D) comprises at least one further coil connected in series with the coil.

12. The choke according to claim 1 or 2, wherein: The choke (D) has at least one high-voltage connection (DF1) for making electrical contact with the coil (S).

13. The choke according to claim 1 or 2, wherein: The choke (D) is designed as a fixed inductive choke.

14. A test device for performing a high voltage test on a test piece (P), wherein: The test device has one or more chokes connected in series or in parallel, wherein at least one of the chokes is designed according to one of claims 1 to 13 .

15. The testing device according to claim 14, wherein: The test device comprises a feeder (EQ) which can be connected to the one or more chokes and the test piece (P) to form a resonant circuit.

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