High-voltage bushing for a high-voltage system

Abstract

The invention relates to a high-voltage bushing for the passage of an electrical conductor (2) through a housing of a high-voltage system, comprising an insulation body (3), through which the conductor (2) is guided, a fastening flange (4) for fastening the high-voltage bushing (1) to an outer wall (5) of the housing and at least one electrically conductive control electrode (6) arranged in the insulation body (2), wherein: the control electrode (6) is arranged substantially concentrically around the conductor (3); an earthing connection (7) connected to the control electrode (6) is provided in order to be able to earth the control electrode (6); an electrically conductive measuring electrode (8) arranged in the insulation body (3) is provided; a capacitive tap (9) which is connected to the measuring electrode (8) and is guided out of the insulation body (3) is provided; the measuring electrode (8) is arranged substantially concentrically around the conductor (2); and the control electrode (7) is arranged substantially concentrically around the measuring electrode (8) and substantially completely surrounds it.

Description

[0001] 64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT)

[0002] High-voltage bushing for a high-voltage system

[0003] The invention relates to a high-voltage bushing for passing an electrical conductor through a housing of a high-voltage system.

[0004] High-voltage bushings, also known as feedthroughs, are known from the prior art for passing an electrical conductor through the housing of a high-voltage system. Such high-voltage bushings have an insulating body, a conductor passing through the insulating body, and a mounting flange for attaching the bushing to a wall of the housing. During operation, the current-carrying conductor is at a high-voltage potential of typically about 17.5 kV or about 36 kV, although values ​​from 1 kV to 50 kV are possible.

[0005] Such a high-voltage bushing isolates the conductor at high-voltage potential from the surroundings at earth potential, in particular the wall of the high-voltage system's housing. For this purpose, the high-voltage bushing is usually fixed to the wall. For example, DE 102022203717 B4 discloses a high-voltage bushing of this type from the prior art. 64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT). To measure the current of the conductor, it is known from the prior art to arrange a current sensor (LPCT, Low Power Current Transformer) around the high-voltage bushing. Such a current sensor is often designed as a contactless inductive ring sensor, in particular as a Rogowski coil.

[0006] To measure the electrical potential of the conductor, a separate, resistive-capacitive voltage sensor, a so-called LPVT (Low Power Voltage Transformer), is typically used. For this purpose, however, the conductor must be routed out of the high-voltage bushing and insulated with additional cable accessories. The voltage sensor is usually attached to the cable accessory by either pushing it on or screwing it on.

[0007] These established configurations, however, have the disadvantage that separate sensors must be attached to the high-voltage bushing. This requires additional space, which is often unavailable, especially in high-voltage switchgear. Furthermore, the current and voltage sensors must be compatible with the external shape of the high-voltage bushing to allow for gap-free mounting, either by pushing or screwing them on. The external shape of the high-voltage bushing varies between manufacturers, necessitating the availability of conventional current and voltage sensors with different form factors. Additionally, on-site installation must be carried out by service providers, leading to a high potential for errors.

[0008] The object of the invention is therefore to solve the above-mentioned problems and to create a high-voltage feedthrough which makes it possible to measure both the current carried and the electrical potential of the conductor in a cost-saving and space-saving manner.

[0009] These and other problems are solved with a high-voltage bushing according to claim 1.64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT) A high-voltage bushing according to the invention serves for the insulated passage of an electrical conductor through a housing of a high-voltage system and comprises an insulating body through which the conductor is guided, a mounting flange for attaching the high-voltage bushing to an outer wall of the housing, and at least one electrically conductive control electrode arranged in the insulating body.

[0010] According to the invention, the control electrode is arranged essentially concentrically around the conductor. The insulating body can preferably be formed from a hardened casting resin.

[0011] A grounding terminal is provided, connected to the control electrode, to allow the control electrode to be grounded. The grounding terminal can preferably be located in the insulating body or in the mounting flange of the high-voltage bushing. The control electrode enables a defined electric field distribution within the insulating body. The control electrode can be connected to a capacitive voltage indicator (CVI) system via the grounding terminal. In this case, it forms a capacitive voltage divider with an external capacitor.

[0012] According to the invention, in addition to the control electrode, an electrically conductive measuring electrode is provided, arranged within the insulating body. The measuring electrode is arranged essentially concentrically around the conductor. A capacitive tap, connected to the measuring electrode and extending out of the insulating body, is provided.

[0013] The control electrode is arranged essentially concentrically around the measuring electrode. According to the invention, the control electrode essentially completely surrounds the measuring electrode. Preferably, the control electrode projects beyond the measuring electrode at both ends.

[0014] In operation, the signal measured at the capacitive tap is a direct measure of the conductor's electrical voltage. The measuring electrode and capacitive tap according to the invention thus allow purely capacitive voltage measurement directly in the high-voltage bushing, without the need for an additional voltmeter. 64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT) To obtain more accurate results, the conductor can be set to a reference potential during the installation of the high-voltage bushing to calibrate the signal at the capacitive tap. The signal measured at the capacitive tap can be further processed using an external data processing unit.

[0015] The control electrode can be connected to a voltage indicator system via the grounding terminal to show whether the conductor is live. However, in this case, an exact potential measurement is not possible. An increased tolerance of up to 50% amplitude deviation allows for no accuracy in measuring the phase shift.

[0016] A high-voltage bushing according to the invention can be pre-assembled at the switchgear manufacturer's factory, thus eliminating the need for error-prone on-site assembly.

[0017] According to the invention, the control electrode and the measuring electrode can be designed in a substantially hollow cylindrical shape. The electrodes can also include rod-shaped control elements arranged in concentric rings.

[0018] Furthermore, according to the invention, at least two field control electrodes arranged substantially concentrically around the measuring electrode can be provided in addition to the external control electrode. These field control electrodes can be arranged outside the measuring electrode. In particular, it can be provided that the measuring electrode has the smallest diameter, while the control electrode and the at least two further field control electrodes have larger diameters. In particular, the field control electrodes can have a larger diameter than the control electrode.

[0019] According to the invention, the control electrode can be longer than the measuring electrode, in particular by a factor of about 50%, 100%, 150%, 200%, 300%, 400% or more. 64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT). For example, the control electrode can extend substantially over the entire length of the high-voltage bushing or at least about 90% of the high-voltage bushing, while the measuring electrode extends only over a small part of the length of the high-voltage bushing, for example, only about 20%. The control electrode can project beyond the measuring electrode at both ends.

[0020] According to the invention, the control electrode and the measuring electrode can be arranged in the insulating body without spacers. This has the advantage that no additional separating layers are formed in the resin potting compound, which could potentially lead to partial discharges. The distance between the control electrode and the measuring electrode can be, for example, approximately 5 mm or approximately 10 mm.

[0021] According to the invention, a temperature sensor element can be arranged on the outer circumference of the insulating body. The temperature sensor element can be a platinum resistance thermometer. The temperature sensor element can, for example, be glued to the outer circumference of the insulating body; this has the advantage that it can be easily replaced if damaged.

[0022] The invention further comprises a measuring arrangement with a high-voltage feedthrough according to the invention, wherein an inductive ring sensor is provided around the insulating body for contactless measurement of the current carried in the conductor, and wherein the ring sensor preferably has an earthing connection.

[0023] According to the invention, a data processing unit connected to the ring sensor via a data line may be provided. The data line may, for example, be an RJ45 cable. The data processing unit may be designed as a microcontroller or microcomputer and may include a central processing unit (CPU), volatile semiconductor memory (RAM), non-volatile semiconductor memory (ROM, SSD hard drive), magnetic storage (hard drive) and / or optical storage (CD-ROM), as well as interface units (Ethernet, USB) and the like. The components of such data processing units are generally known to those skilled in the art. 64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT) The data processing unit may be implemented with or without grounding. The capacitive tap of the measuring electrode may be connected directly or via a line in the ring sensor to the data processing unit.

[0024] The data processing unit allows the measurement signal to be modulated, calibrated, and, if necessary, compensated for by temperature or external field control. This ensures amplitude and phase accuracy. An additional power connection can be used for the external data processing unit. The external data processing unit can be divided into several different housings, which, depending on their function, can be equipped with visual elements as well as operating functions.

[0025] In particular, the data processing unit can be configured to compensate for the temperature drift of the measured current and / or voltage. Such temperature drift arises from temperature changes in the insulating body, leading to a shift in the zero point or sensitivity and impairing accuracy. For this purpose, the measured temperature is transmitted from the temperature sensor element to the data processing unit via the common data line. Separate compensation curves for current and voltage, depending on the temperature, are stored in the data processing unit to compensate for the current and voltage measurements. This has the advantage that the measurement setup is device-independent, as the temperature compensation does not need to be implemented in external devices.

[0026] According to the invention, the ring sensor can be configured to receive an inductive current measurement signal, a capacitive voltage measurement signal from the capacitive tap, and a temperature measurement signal from the temperature sensor element and transmit them together via the data line to the data processing unit. The data processing unit can then compensate for the temperature dependence of the current measurement signal and the voltage measurement signal using internally stored temperature compensation curves for current and voltage. 64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT) Further features of the invention will become apparent from the claims, the following description of the exemplary embodiment, and the figures.

[0027] The invention is further explained using an exemplary embodiment. Figures 1a and 1b show schematic views of an embodiment of a high-voltage bushing according to the invention.

[0028] Fig. 1a shows an embodiment of a high-voltage bushing 1 according to the invention in a schematic cross-sectional view. The high-voltage bushing 1 has a cylindrical insulating body 3, which is attached to the outer wall 5 of a housing of a high-voltage system via a mounting flange 4. An electrical conductor 2 passes through the outer wall and longitudinally through the electrically insulating body 3.

[0029] The insulating body 3 can contain cured resin. Such an insulating body 3 forms a solid block to which the mounting flange 4 can be directly attached.

[0030] An electrically conductive control electrode 6 is arranged in the insulating body 3. The control electrode 6 is arranged essentially concentrically around the conductor 2 and can be designed as a metal braid or metal cage. A grounding terminal 7, connected to the control electrode 6, is provided on the outer surface of the insulating body 3 to ground the control electrode 6. The grounding terminal 7 is located on the outer surface of the insulating body 3, but it can also be located on the mounting flange 4.

[0031] During operation of the high-voltage bushing 1, the control electrode 6 can be connected to earth potential via the grounding terminal 7. An electrical conductor, e.g., a conductive strip or the like, embedded in the insulating body 3, can be provided for grounding the control electrode 6. In the present embodiment, the control electrode 6 is connected via the grounding terminal 7 to a capacitive voltage indicator system 12 to indicate the presence of an electrical potential on the conductor. 64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT) According to an embodiment of the invention not shown, the insulating body 3 comprises further electrically conductive control inserts (not shown) for field control.The control inserts can be formed as an electrically conductive grid made of a metal alloy or a comparable electrically conductive material, optionally also of conductive plastic or a conductive coating. The control inserts can be arranged substantially concentrically to the conductor. The control inserts can be spaced apart from each other by insulating layers made of a suitable material, such as paper or a synthetic insulating material. The control inserts can be arranged concentrically to the conductor 2 and outside the control electrode 6.

[0032] An inductive ring sensor 10 is provided around the insulating body 3 for measuring the current carried in conductor 2. The ring sensor 10 can, for example, be a Rogowski coil for measuring the alternating current in the electrical conductor 2.

[0033] The ring sensor 10 also has a grounding connection, which in the present embodiment is connected to ground.

[0034] An electrically conductive measuring electrode 8 is provided in the insulating body 3, extending substantially concentrically around the conductor 2. The measuring electrode 8 is arranged within and concentrically to the control electrode 6. The control electrode 6 is arranged substantially concentrically around the measuring electrode 8 and substantially surrounds it completely. The control electrode 6 extends over approximately 80% of the length of the insulating body 3, while the measuring electrode extends over only approximately 15% of the length of the insulating body 3. The control electrode 6 projects beyond the measuring electrode 8 at both ends. In this embodiment of the invention, the control electrode 6 covers, in particular, that region of the conductor 2 which surrounds the ring sensor 10, as well as the region of the mounting flange 4.

[0035] A capacitive tap 9, connected to the measuring electrode 8 and extending from the insulating body 3, is provided. Furthermore, a data processing unit 11, connected to the ring sensor 10 via a data line 14, is provided. 64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT) The ring sensor 10 is connected to the capacitive tap 9. In the ring sensor 10, the signal from the capacitive tap 9 is forwarded via the data line 14 to the data processing unit 11.

[0036] According to an embodiment of the invention not shown, the ring sensor 10 is embedded directly in the mounting flange 4.

[0037] The data processing unit 11 receives the measurement signal from the capacitive tap 9 via a data connection from the ring sensor 10. This data connection is, for example, an RJ45 Ethernet connection. Since the ring sensor 10 is grounded, the data processing unit 11 can compare the received measurement signal to ground and, based on a prior calibration, determine the electrical potential of conductor 2.

[0038] This enables the output of a standardized signal according to, for example, IEC 61869-11. The required calibration values ​​can be pre-stored in a static memory of the data processing unit 11, so that no recalibration is necessary even in the event of a power failure.

[0039] In addition, the data processing unit 11 also receives a measurement signal from the ring sensor 10 via the data line 14 and can therefore also determine the alternating current carried in conductor 2.

[0040] Furthermore, the data processing unit 11 also receives a temperature measurement signal from the temperature sensor element 13 via the data line 14. Using internally stored compensation curves, the data processing unit 11 compensates for the temperature drift of the voltage signal and the current signal.

[0041] Fig. 1b shows a schematic side sectional view of the measuring arrangement from Fig. 1a, although the exposed taps 7, 9 and the data processing unit 11 are not shown. 64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT) The illustration essentially shows the concentric arrangement of the control electrode 6 and the measuring electrode 8 around the electrical conductor 2 as well as the arrangement of the ring sensor 10.

[0042] However, the invention is not limited to the described embodiment, but includes all high-voltage feedthroughs and measuring arrangements within the scope of the following patent claims.

Claims

64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT) Patent claims 1. High-voltage bushing (1 ) for passing an electrical conductor (2) through a housing of a high-voltage system, comprising a. an insulating body (3) through which the conductor (2) is passed, b. a mounting flange (4) for attaching the high-voltage bushing (1) to an outer wall (5) of the housing, c. at least one electrically conductive control electrode (6) arranged in the insulating body (3), wherein d. the control electrode (6) is arranged substantially concentrically around the conductor (2), and wherein e. a grounding connection (7) connected to the control electrode (6) is provided in order to ground the control electrode (6), characterized in that f. an electrically conductive measuring electrode (8) arranged in the insulating body (3) is provided, wherein g. a capacitive tap (9) connected to the measuring electrode (8) and extending out of the insulating body (3) is provided, wherein h. the measuring electrode (8) is arranged substantially concentrically around the conductor (2), and wherein i. the control electrode (6) is arranged substantially concentrically around the measuring electrode (8) and substantially completely surrounds it.

2. High-voltage feedthrough (1) according to claim 1, characterized in that the control electrode (6) and the measuring electrode (8) are essentially hollow cylindrical in shape.

3. High-voltage bushing (1) according to claim 1 or 2, characterized in that, in addition to the control electrode (6), at least two field control electrodes arranged substantially concentrically around the measuring electrode (8) are provided. 64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT) 4. High-voltage bushing (1) according to one of claims 1 to 3, characterized in that the control electrode (6) is longer than the measuring electrode (8), in particular by a factor of about 50%, 100%, 150%, 200%, 300%, or 400%.

5. High-voltage feedthrough (1) according to one of claims 1 to 4, characterized in that the control electrode (6) and the measuring electrode (8) are arranged without spacers in the insulating body (3).

6. High-voltage feedthrough (1) according to one of claims 1 to 4, characterized in that a temperature sensor element (13), in particular a Pt resistance thermometer, is arranged on the outer circumference of the insulating body (3).

7. Measuring arrangement comprising a high-voltage feedthrough (1) according to one of claims 1 to 6, characterized in that an inductive ring sensor (10) is provided around the insulating body (3) for contactless measurement of the current carried in the conductor (2), wherein the ring sensor (10) preferably has an earthing connection.

8. Measuring arrangement according to claim 7, characterized in that a data processing unit (11) is provided which is connected to the ring sensor (10) via a data line (14).

9. Measuring arrangement according to claim 7 or 8, characterized in that the ring sensor (10) is connected to the capacitive tap (9).

10. Measuring arrangement according to one of claims 7 to 9, characterized in that the ring sensor (10) is connected to the temperature sensor element (13).

11. Measuring arrangement according to claim 10, characterized in that the ring sensor (10) is configured to transmit an inductive current measurement signal, a capacitive voltage measurement signal, and a temperature measurement signal via the data line (14) to the data processing unit (11). 64723 / AG / - Greenwood-Power GmbH, Industriestraße B 6-8, 2345 Brunn am Gebirge (AT) 12. Measuring arrangement according to claim 11, characterized in that the data processing unit (11) is configured to compensate for the temperature dependence of the current measurement signal and the voltage measurement signal using internally stored temperature compensation curves for current and voltage.

13. Measuring arrangement according to one of claims 7 to 12, characterized in that the control electrode (6) is connected to a voltage display system (12) via the grounding connection (7).

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