Measuring device for measuring the voltage potential at a conductor in a power switching device and corresponding power switching device

Abstract

The invention relates to a voltage potential measuring device for measuring the voltage potential at a conductor (18) in an encapsulated power switching device (12), wherein at least one section of the conductor (18) is surrounded by a field control component (24), in particular a field control electrode (22), and the voltage potential measuring device has a measuring electrode (30) for capacitive coupling with the conductor (18). Provision is made for the measuring electrode (30) to be arranged outside the field control component (24) and for the field control component (24) to be penetrated by at least one opening (32) at the level of the measuring electrode (30). The invention also relates to a corresponding encapsulated power switching device (12).

Description

Technical Field

[0001] The invention relates to a voltage potential measuring device for measuring a voltage potential on a conductor within an encapsulated power switching device, wherein at least one section of the conductor is surrounded by a substantial field control component, in particular a field control electrode, and the voltage potential measuring device has a measuring electrode for capacitive coupling to the conductor.

[0002] The present invention also relates to a corresponding encapsulated power switching device. Background Art

[0003] Power switching devices (circuit breakers) connect or disconnect current paths with high voltage and high current. Current and voltage are measured using current transformers or voltage transformers. The voltage potential at a conductor (primary conductor) is measured via capacitive coupling between the conductor and the measuring electrode. To this end, the measuring electrode must be arranged in close proximity to the conductor. The encapsulated conductive housing components shield the electric field of the conductor. Field control components, such as the control electrodes of high-voltage bushings of dead-tank switchgear, also have a shielding effect. Therefore, the measuring electrode cannot be installed in such an installation position, for example, for a current transformer. Therefore, in many cases, the measuring electrode is embedded in a switch housing filled with insulating gas, so that it is in close proximity to the conductor. As a result, the electric field of the conductor can act on the measuring electrode without being affected.

[0004] Document DE 198 30 067 C1 shows a voltage potential measuring device for measuring the voltage potential at a conductor, referred to as a current path, within an encapsulated power switching device designed as a pressure gas circuit breaker, wherein at least one section of the conductor is surrounded by an outer contour in the form of a shielding electrode, and the voltage potential measuring device has a measuring electrode for capacitive coupling to the conductor.

[0005] In the present embodiment of this power switching device, the field control component is designed as a substantially sleeve-shaped field control electrode. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a voltage potential measuring device for measuring the voltage potential at a conductor inside an encapsulated power switching device and a corresponding encapsulated power switching device, wherein the voltage potential measuring device and the encapsulated power switching device open up new installation possibilities for measuring electrodes, in particular installation possibilities that enable simple installation of the measuring electrodes.

[0007] According to the invention, the above-mentioned object is achieved by the features of the independent claims.

[0008] Advantageous embodiments of the invention are the subject matter of the dependent claims.

[0009] In a voltage potential measuring device according to the present invention for measuring the voltage potential at a conductor within an encapsulated power switching device, wherein at least one section of the conductor is surrounded by a field control component, the voltage potential measuring device has a measuring electrode for capacitive coupling with the conductor. Provision is made for the measuring electrode to be arranged outside the field control component and for the field control component to be penetrated by at least one opening at the level of the measuring electrode. The opening is a window and forms a passage for field lines between the conductor and the measuring electrode. The field lines form the electrodes of a capacitor. In this way, capacitive coupling between the conductor and the measuring electrode can be achieved despite the presence of the field control component. The field control component is preferably a field control electrode, in particular a substantially sleeve-shaped field control electrode.

[0010] These measures result in new installation possibilities for the measuring electrodes. In this way, it is possible to measure the voltage potential even in the vicinity of a current measurement of the current flowing through the conductor.

[0011] According to a preferred embodiment of the present invention, the measuring electrode is annular in shape, and the field control component is penetrated by a plurality of circumferentially distributed openings at the level of the measuring electrode. Annular measuring electrodes encircling a conductor have proven reliable for measuring the voltage potential at the conductor.

[0012] According to another preferred embodiment of the present invention, the encapsulation is designed as a high-voltage insulator that circumferentially surrounds the field control component, at least at the level of the measuring electrode. The high-voltage insulator is typically made of a ceramic material or a GFK-silicon composite material.

[0013] Circuit breakers (circuit breakers for short) typically have such high-voltage insulators in their high-voltage bushings. Accordingly, the measuring device measures the voltage potential on a conductor in the region of the high-voltage bushing of the encapsulated circuit breaker. Advantageously, the current flowing through the conductor is also measured there.

[0014] In this case, the measuring electrodes are also arranged outside the high-voltage insulator. The high-voltage insulator is a dielectric window and forms a passage for the field lines between the conductor and the measuring electrodes. The measuring electrodes can be mounted outside the high-voltage insulator in a particularly simple manner.

[0015] According to another preferred embodiment of the present invention, the field control component is directly connected to the switch housing of the power switching device. Such an arrangement of the switch housing and the field control component is provided in many power switching devices.

[0016] Advantageously, at least two of the following components, comprising the conductor, the field control component, and the measuring electrode, are oriented coaxially. The high-voltage insulator is often also oriented coaxially therewith. Such an arrangement is often provided in high-voltage bushings.

[0017] In the encapsulated power switching device according to the present invention, the power switching device comprises (i) a switching unit, (ii) a conductor electrically connected to the switching unit, (iii) an encapsulation, (iv) a field control component and (v) a measuring electrode for measuring a voltage potential at the conductor, wherein the measuring electrode is arranged outside the field control component and the field control component is penetrated by at least one opening at the height of the measuring electrode.

[0018] In other words, the aforementioned voltage potential measuring device for measuring the voltage potential at a conductor within the encapsulated power switching device is implemented in the power switching device.

[0019] In this case, according to one embodiment of the encapsulated power switching device according to the invention, it is provided that the measuring electrode is annular in shape and that the field control component is penetrated by a plurality of circumferentially distributed openings at the level of the measuring electrode.

[0020] In another embodiment of the encapsulated power switching device according to the invention, it is provided that the encapsulation is designed as a high-voltage insulator circumferentially surrounding the field control component at least at the level of the measuring electrode, wherein the measuring electrode is preferably also arranged outside the high-voltage insulator.

[0021] In this case, it is preferably provided that the field control component is connected directly to a switch housing of the power switching device which accommodates the switching unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The characteristics, features and advantages of the present invention described above and their implementation will be more clearly understood in conjunction with the following description of the embodiments described in detail in conjunction with the accompanying drawings. In the accompanying drawings:

[0023] Figure 1 A cross-sectional view shows a high-voltage bushing of an encapsulated power switch device connected to a switch housing according to an embodiment of the present invention, and

[0024] Figure 2 The field control electrodes arranged in this part of the high voltage bushing are shown. DETAILED DESCRIPTION

[0025] Figure 1The section of the encapsulated power switching device 12 connected to the switch housing 10 is shown in cross section. This section of the encapsulated power switching device 12 is a high-voltage bushing 14. The section shown by the switch housing 10 is a substantially cylindrical support and has an opening 16 at its head end, through which a conductor 18 can be led out of the switch housing 10 and introduced into the high-voltage bushing 14.

[0026] In such a circuit breaker device 12 , the switch housing 10 accommodates one or more switching units (not shown here). The cylindrical support and the conductor 18 of the switch housing 10 shown are arranged coaxially, ie, lie on a common axis 20 .

[0027] A field control component 24, designed as a substantially sleeve-shaped field control electrode 22, is flange-connected to the head end of the illustrated portion of the switch housing 10. This field control component completely surrounds the conductor 18 in section A of the conductor 18. The sleeve-shaped field control electrode 22 is then completely surrounded on its side by a preferably ceramic high-voltage insulator 26, which forms part of the high-voltage bushing 14. The field control electrode 22 and the high-voltage insulator 26 are also oriented coaxially with respect to the axis 20. The switch housing 10 and the high-voltage insulator 26 are part of the encapsulation 28 of the encapsulated power switching device 12.

[0028] An annular measuring electrode 30 surrounds the high-voltage insulator 26 at the height h of the section A. The field control element 24 , designed as a field control electrode 22 , is penetrated at the height of the measuring electrode 30 by a plurality of circumferentially distributed openings 32 , each forming a passage between the conductor 18 and the measuring electrode 30 .

[0029] Thus, a voltage potential measuring device is obtained in the region of the high-voltage bushing 14, which is used to measure the voltage potential at a conductor 18 arranged inside the encapsulated power switching device 12, wherein at least a section A of the conductor 18 inside the high-voltage bushing 14 is surrounded by a field control electrode 22. The device has a measuring electrode 30 for capacitive coupling with the conductor 18, which is arranged outside the field control electrode 22, wherein the field control electrode 22 is penetrated by a plurality of openings 32 between the conductor 16 and the measuring electrode 30 at the height of the measuring electrode 30. In this case, the field control electrode 22 and the section A of the conductor 18 are located inside the high-voltage bushing 14, and the measuring electrode 30 surrounds the outer circumference of the high-voltage bushing 14 at a height h.

[0030] The encapsulated circuit breaker 12 can be designed as a vacuum circuit breaker 12 or, as in this case, as a gas-filled circuit breaker 12. It can be designed as a so-called live tank circuit breaker, a dead tank circuit breaker or as a hybrid circuit breaker.

[0031] Figure 2 Another cross-sectional view shows the arrangement (in Figure 1 The field control electrode 22 is shown in FIG. The field control electrode 22 is designed in a sleeve-shaped manner and is made, for example, from sheet metal. A flange 34 is located at one end of the field control electrode 22, via which the field control electrode 22 can be mounted (flange-connected) to the switch housing 10. An annularly curled edge 36 is located at the other end of the field control electrode 22, which particularly stabilizes the shape of the field control electrode 22 at this "open end." The opening 32 is arranged significantly closer to the end having the flange 34 than to the open end (the other end having the annularly curled edge 36).

[0032] The radially extending openings 32 formed in the wall 38 have a uniform rectangular contour and are arranged so closely one behind the other in the circumferential direction that only relatively narrow webs 40 remain between the openings, the width of each of which is significantly smaller than the size of the openings (openings) 32. Figure 2 In the example shown, the web 40 has a width that is less than one third of the circumferential extension of the opening 32 .

[0033] The essential details of the voltage potential measuring device for measuring the voltage potential at the conductor 16 inside the encapsulated power switching device 12 will be described again in a different language below.

[0034] Measuring electrodes 30 for measuring voltage are mounted outside the switch housing 10 at the base of the high-voltage insulator 26. The field control component 24 of the high-voltage bushing 14, namely the field control electrode 22, is penetrated by an opening (opening 32). The opening 32 in the field control electrode 22 interrupts the shielding effect. The electric field of the primary conductor 18 can act on the measuring electrode 30. This achieves capacitive coupling between the primary conductor 18 and the measuring electrode 30, enabling the measurement of the primary voltage in close proximity to the current measurement.

[0035] Reference Signs List

[0036] 10 Switch housing

[0037] 12 Power switching device

[0038] 14 High voltage bushing

[0039] 16 openings

[0040] 18 conductors

[0041] 20 axis

[0042] 22 Field control electrodes

[0043] 24 Field control components

[0044] 26 High voltage insulator

[0045] 28 Package

[0046] 30 Measuring electrodes

[0047] 32 openings

[0048] 34 flange

[0049] 36 Hemmed Edges

[0050] 38 wall

[0051] 40 belly plate

[0052] Section A

[0053] H Height

Claims

1. A voltage potential measuring device for measuring a voltage potential at a conductor (18) inside an encapsulated power switching device (12), wherein: At least one section (A) of the conductor (18) is surrounded by a field control component (24), the voltage potential measuring device having a measuring electrode (30) for capacitive coupling with the conductor (18), It is characterized in that the measuring electrode (30) is arranged outside the field control component (24), and the field control component (24) is penetrated by at least one opening (32) at the level of the measuring electrode (30).

2. The voltage potential measuring device according to claim 1, characterized in that The measuring electrode (30) is annular in design, and the field control element (24) is penetrated by a plurality of circumferentially distributed openings (32) at the level of the measuring electrode (30).

3. The voltage potential measuring device according to claim 1 or 2, characterized in that: The encapsulation (28) is designed as a high-voltage insulator (26) circumferentially surrounding the field control component (24), at least at the level of the measuring electrode (30).

4. The voltage potential measuring device according to claim 3, characterized in that The measuring electrode (30) is also arranged outside the high-voltage insulator (26).

5. The voltage potential measuring device according to claim 1 or 2, characterized in that: The field control component (24) is directly connected to the switch housing (10) of the power switch device (12).

6. The voltage potential measuring device according to claim 1 or 2, characterized in that: At least two of the following components are coaxially oriented, the components comprising a conductor (18), a field control component (24) and a measuring electrode (30).

7. A packaged power switch device having -Switching unit, - a conductor (18) electrically connected to the switching unit, - Encapsulation (28), - Field control unit (24) and - a measuring electrode (30) for measuring the voltage potential at the conductor (18), It is characterized by: The measuring electrode (30) is arranged outside the field control component (24), and the field control component (24) is penetrated by at least one opening (32) at the level of the measuring electrode (30).

8. The power switch device according to claim 7, characterized in that: The measuring electrode (30) is annular in design, and the field control element (24) is penetrated by a plurality of circumferentially distributed openings (32) at the level of the measuring electrode (30).

9. The power switch device according to claim 7 or 8, characterized in that: The encapsulation (28) is designed to circumferentially surround the high-voltage insulator (26) of the field control component (24) at least at the level of the measuring electrode (30), wherein the measuring electrode (30) is also arranged outside the high-voltage insulator (26).

10. The power switch device according to claim 9, characterized in that: The field control component (24) is directly connected to a switch housing (10) of the power switching device (12) accommodating the switching unit.

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