PLUGGABLE HIGH-VOLTAGE BUSHING AND ELECTRICAL DEVICE HAVING THE PLUGGABLE HIGH-VOLTAGE BUSHING

Abstract

A pluggable high-voltage feed-through has an inner conductor, which extends in a longitudinal direction between a high-voltage connection and a plug-in section of the high-voltage feed-though. The plug-in section is configured for plugging the high-voltage feed-though into a device connection part of an electrical device. An insulating body surrounds the inner conductor. A test tapping point is provided with an electrical contact for connecting to a connection of a measuring device. The test tapping point is arranged outside the plug-in section. An electrical device has a fluid-tight housing and the high-voltage feed-through. A device connection part is provided for receiving and contacting the high-voltage feed-through.

Claims

1-13. (canceled)

14. A pluggable high-voltage bushing, comprising: a plug-in portion configured for plugging the high-voltage bushing into a device connection part of an electrical device; an inner conductor extending longitudinally between a high-voltage connection and said plug-in portion of the high-voltage bushing; an insulating body enclosing said inner conductor; and a test tap with an electrical contact for connecting to a connection of a measuring device, said test tap being arranged outside said plug-in portion.

15. The high-voltage bushing according to claim 14, wherein said electrical contact of said test tap has a measurement connection line enclosed in an insulation.

16. The high-voltage bushing according to claim 15, wherein said insulating body comprises field-controlling control inserts and insulating layers separating said control inserts from one another, and wherein said measurement connection line is electrically connected to one of said control inserts.

17. The high-voltage bushing according to claim 16, wherein said measurement connection line is electrically connected to a second outermost control insert, with said test tap forming a voltage divider tapping.

18. The high-voltage bushing according to claim 17, wherein said voltage divider tapping comprises an auxiliary bushing disposed to insulate and guide said measurement connection line of said contact through an outer housing of the high-voltage bushing.

19. The high-voltage bushing according to claim 14, wherein said test tap includes a grounding device for grounding said contact.

20. The high-voltage bushing according to claim 14, wherein said insulating body comprises field-controlling control inserts arranged concentrically around said inner conductor and extending into said plug-in portion.

21. The high-voltage bushing according to claim 14, wherein said insulating body comprises a cured resin.

22. The high-voltage bushing according to claim 14, further comprising a securing flange for securing the high-voltage bushing to a housing of the electrical device.

23. An electrical device, comprising: a fluid-tight housing; a high-voltage bushing according to claim 14; and a device connection part for receiving and contacting said high-voltage bushing.

24. The electrical device according to claim 23, further comprising a securing portion for securing said device connection part to said housing, a hollow receiving portion composed of an electrically nonconductive insulating material extending from said securing portion into said housing, and a metallic contact part arranged at a closed tapered end region, said contact part extending through said insulating material of said receiving portion or lengthening said receiving portion toward said closed tapered end region.

25. The electrical device according to claim 24, wherein said contact part is connected to a winding via a winding connection line extending inside said housing.

26. The electrical device according to claim 25, wherein said winding connection line is equipped with a current sensor.

Description

[0024] The invention will be explained in further detail below with reference to FIGS. 1 and 2.

[0025] FIG. 1 shows one exemplary embodiment of an electrical device according to the invention comprising a high-voltage bushing according to the invention in a schematic partial cross-sectional view;

[0026] FIG. 2 shows a basic schematic diagram of a high-voltage bushing according to the invention comprising a test tap in the form of a voltage divider tapping.

[0027] FIG. 1 illustrates a partial excerpt from an electrical device in the form of a transformer 1 comprising a pluggable high-voltage bushing 2 and a device connection part 3 for receiving and contacting the high-voltage bushing 2. In the illustration in the figure, the high-voltage bushing 2 is plugged into the device connection part 3 of the transformer 1. The device connection part 3 is secured to a housing wall 4. The housing wall 4 delimits an interior 5 of a transformer housing of the transformer 1, said housing being filled with an insulating medium, for example insulating oil. The securing of the high-voltage bushing 2 to the housing wall 4 is embodied in an insulating-medium-tight fashion, such that the insulating medium cannot escape from the housing. The device connection part 3 comprises a conductive connection part 6 for establishing an electrical connection between the high-voltage bushing 2 and a transformer winding (not illustrated in the figures) of the transformer 1, said winding being arranged inside the housing filled with insulating oil.

[0028] The high-voltage bushing 2 comprises an inner conductor 7, which is embodied as a hollow conductor composed of aluminum or copper in the example illustrated. The inner conductor 7 is surrounded concentrically by an insulating body 8. The insulating body 8 comprises conductive control inserts 9a-c for capacitive field control, which are arranged concentrically around the inner conductor 7. The control inserts 9a-c are separated from one another by insulating layers 10a-b composed of a PET nonwoven material, which insulating layers have been impregnated in resin after being wound onto the inner conductor 7. The control inserts 9a-c are arranged at a radial distance A of 2 mm from one another.

[0029] The high-voltage bushing 2 furthermore comprises a plug-in portion 11 for plugging the high-voltage bushing 2 into the device connection part 3. The plug-in portion 11 comprises a conically tapering part of the insulating body 8 and also a connection conductor portion welded to the inner conductor 7 in the form of a conductor bolt 12. Adjacent to the conductor bolt 12 is a contact system 13, which establishes the electrical connection between the high-voltage bushing 2 and the connection part 6.

[0030] An interspace 14 between the plug-in portion 11 of the high-voltage bushing 2 and the device connection part 3 is filled with a silicone material, which dielectrically strengthens the interspace 14.

[0031] The high-voltage bushing 2 furthermore comprises a securing flange 15 for securing the high-voltage bushing 2 to the device connection part 3.

[0032] In order to produce the electrical device 1, the high-voltage bushing 2 is inserted into the device connection part 3, specifically along a longitudinal axis 16 of the high-voltage bushing 2 and in the direction indicated by an arrow 17 in the figure. Afterward, the securing flange 15 can be mechanically connected to the device connection part 3 with the aid of securing elements 18a,b.

[0033] It is evident that the device connection part 3 has a securing portion 19, by which said device connection part is fixedly mounted on the housing wall 4. This is done using suitable screw connections, for example. In order to secure the device connection part 3 to the housing wall 4 in an insulating-medium-tight fashion, sealants (not illustrated in the figures) are provided.

[0034] The device connection part 3 furthermore has a receiving portion 20 consisting of an electrically nonconductive material. In this case, the receiving portion 20 tapers toward a closed end. At the closed end, the bolt-type connection or contact part 6 projects through the wall of the receiving portion 20. At its portion projecting into the interior 5 or oil space of the housing, the contact part 6 is connected to a winding connection line 22. The winding connection line 22 is furthermore equipped with a current sensor in the form of a current converter (not illustrated in the figures). The current converter is thus fixedly installed in the housing and serves for detecting an electric current flowing to or from the respective winding via the winding connection line 22.

[0035] The plug-in portion 11 of the high-voltage bushing 2 extends from the securing flange 15 into the receiving portion 20 of the device connection part 3. In this case, the plug-in portion 11 has a complementary shape with respect to the receiving portion 20, such that the two components bear against one another with an accurate fit and air or other inclusions can be avoided.

[0036] The high-voltage bushing 2 furthermore comprises a voltage divider tapping 23 with an electrical contact means 24 for connecting to a connection of a measuring device (not illustrated graphically) for measuring the electrical voltage at the high-voltage bushing 2. The contact means comprises a measurement connection line 24. The voltage divider tapping 23 is arranged above the securing flange 15 and thus also outside the plug-in portion 11 of the high-voltage bushing 2. The measurement connection line 24 is electrically connected to the second outermost control insert 9b. The measurement connection line 24 is guided toward the outside through a cutout in the outermost control insert 9c. An outer housing 26 of the high-voltage bushing 2 has a measurement connection cutout 27. The measurement connection line 24 is guided through the measurement connection cutout 27. The measurement connection cutout 27 with the contact means 24 arranged therein is filled with an insulating material.

[0037] The voltage divider tapping 23 comprises an auxiliary bushing 25, by means of which the measurement connection line 24 is guided through the housing 26 of the high-voltage bushing 2 in an insulated manner. Moreover, a grounding device 28 is provided. The voltage divider tapping 23 can be grounded by means of the grounding device 28. The grounding device 28 comprises a closure cap with a contact spring, which contacts the measurement connection line 24 for the purpose of grounding the voltage divider tapping 23. In the normal operating state of the high-voltage bushing, the voltage divider tapping expediently remains connected to the measurement technology or grounded.

[0038] FIG. 2 shows a high-voltage bushing 30 on the left-hand side and the counterpart of said high-voltage bushing in an equivalent circuit diagram on the right-hand side. The high-voltage bushing 30 comprises an inner conductor 31. An insulating body 32 is arranged around the inner conductor 31. The insulating body 32 is composed of an insulating material, such as paper or nonwoven material, for example, which was impregnated with a resin. The insulating body 32 furthermore comprises field-controlling control inserts 33a-e composed of electrically conductive material, such as aluminum, for example. The innermost control insert 33a is electrically connected to the inner conductor 31. The second outermost control insert 33e is connected to a measurement connection line 34 of a voltage divider tapping 35. The measurement connection line 34 is guided through the outermost control insert 33e and a securing flange 36 in an insulated manner.

[0039] The high-voltage bushing 30 additionally comprises a plug-in portion 37 with a contact system 38 in a corresponding manner to the high-voltage bushing 2 in FIG. 1.

[0040] The following potential points are depicted in the schematic diagram in FIG. 2: A1 is a potential point at the high-voltage conductor 1, A2 is a potential point at the outermost control insert 33e, A3 is a potential point at the second outermost control insert 33d, and A4 is a potential point at the securing flange 36.

[0041] The equivalent circuit diagram on the right-hand side of FIG. 2 illustrates the calculation of the voltage UB between the potential points A1 and A2 from a tapped off voltage between the potential points A3 and A2 and also the main capacitance C1 and the tapping capacitance C2. The voltage is determined in accordance with the equation UB=Um*(C1+C2)/C1. The potential point A3 is insulated from surrounding fields. Consequently, the voltage measurement is largely uninfluenced by external stray capacitances. The capacitances C1 and C2 are additionally known relatively accurately, such that the construction of the voltage divider tapping allows a good measurement accuracy.