DE102020212350A1 - Encapsulated high-voltage device and current transformer for the encapsulated high-voltage device - Google Patents

Abstract

The invention relates to a current transformer (2) for encapsulated high-voltage devices (1) and an encapsulated high-voltage device (1) with the current transformer (2), the current transformer (2) having at least one coil (3) which is wound around at least one current-carrying conductor (4 ) is arranged, wherein the at least one current-carrying conductor (4) is arranged in an encapsulating housing (5) and the at least one coil (3) is an air-core coil without a magnetic core.

Description

The invention relates to a current transformer for encapsulated high-voltage devices and an encapsulated high-voltage device with the current transformer, the current transformer having at least one coil which is arranged around at least one current-carrying conductor, the at least one current-carrying conductor being arranged in an encapsulating housing.

High-voltage devices are designed for voltages in a two-digit kilovolt range up to a voltage range of a few hundred kilovolts, in particular 1200 kV, and for currents in the range of up to a few hundred kiloamperes. High voltage devices include e.g. B. switchgear with high-voltage circuit breakers, isolators, transformers, arresters, instrument transformers and/or bushings. Switchgear are e.g. B. Outdoor switchgear and/or gas-insulated switchgear, d. H. Gas-insulated switchgears, which as a live tank, i. H. at high voltage potential, with a switching unit in an insulator, such as. B. arranged in a ribbed ceramic, silicone and / or composite material insulator housing, executed, or as a dead tank, d. H. are arranged with a switching unit in a grounded housing, in particular in the form of a tank.

The measurement of electrical currents in encapsulated high-voltage devices, in particular gas-insulated switchgears designed as dead tanks, is essential for the operation of the devices, in particular for monitoring, controlling and/or regulating. Electrical currents in the field of encapsulated high-voltage devices are z. B. measured with inductive plug-in current transformers, which are arranged around current-carrying conductors of the high-voltage device. This type of current transformer consists of a toroidal core with a secondary winding, which is arranged concentrically around the current-carrying conductor. The toroidal core is made of high-quality sheet metal with high permeability and is provided with a corresponding secondary winding in particular. In addition to good measuring accuracy, even with high transient voltages/currents, and thermal overcurrent resistance, it is necessary for the measuring device to withstand the mechanical loads that occur, caused by high currents and/or magnetic fields, without damage and/or permanent destruction.

Push-through current transformers have a high intrinsic weight and require a large installation space, are associated with high costs, in particular due to the toroidal core, and have frequency- and amplitude-dependent non-linearities.

The object of the present invention is to provide a current transformer for encapsulated high-voltage devices and an encapsulated high-voltage device with the current transformer, which solve the problems described above. In particular, the task is to specify a current transformer for encapsulated high-voltage devices which is simple and inexpensive, has a low weight, does not require a toroidal core, which has no frequency- and amplitude-dependent non-linearities, and which ensures safe, permanent, non-destructive operation of the high-voltage device with the Current transformer allows.

The specified object is achieved according to the invention by a current transformer for encapsulated high-voltage devices having the features according to patent claim 1 and/or by an encapsulated high-voltage device according to patent claim 12 . Advantageous configurations of the current transformer according to the invention for encapsulated high-voltage devices and/or the encapsulated high-voltage device according to the invention are specified in the dependent claims. Subjects of the main claim can be combined with features of the subclaims and features of the subclaims.

A current transformer according to the invention for encapsulated high-voltage devices comprises at least one coil, which is arranged around at least one current-carrying conductor, wherein the at least one current-carrying conductor is arranged in an encapsulating housing. The at least one coil is designed in the form of an air coil without a magnetic core or is an air coil without a magnetic core.

An air coil without a magnetic core, ie an air coil without a magnetic core, saves a toroidal core, has a lower weight compared to a coil with a magnetic core, is simple and inexpensive, and has no frequency- and amplitude-dependent non-linearities of a coil with a toroidal core. The current transformer according to the invention with the air coil without a magnetic core is smaller in design than with coils with a magnetic core, is lighter and cheaper to buy, the measurement has a high linearity over the entire measuring range and there are no saturation effects. Furthermore, only small electrical losses occur even with high currents and no forces act on the measuring system, ie the current transformer, which means that the implementation of the measuring system in terms of design is considerably simplified. Identical coils can be used for the entire current measurement range from a few amperes to a few hundred kiloamperes, which also represents a cost advantage. Further advantages result from a lower Danger potential for e.g. B. Maintenance personnel dealing with the current transformer and high-voltage device, especially during installation and maintenance. This enables safe, permanent, non-destructive operation of the high-voltage device with the current transformer.

The air-core coil without a magnetic core can be designed in the manner of a Rogowski coil. Rogowski coils can be manufactured easily and inexpensively in large quantities and have the advantages described above.

The at least one coil can be arranged outside of the encapsulating housing. As a result, simple maintenance is possible without opening the encapsulating housing and installation space in the encapsulating housing is saved, which in particular saves costs and material.

The at least one coil can be arranged in a holder, in particular in a groove which can be formed in the holder. The arrangement of the at least one coil in a holder, in particular in a groove, enables precise spatial and permanent positioning of the at least one coil. This enables a precise, error-free measurement of the current through the current-carrying conductor with the current transformer or the at least one coil.

The holder can include a cover which in particular completely covers the at least one coil. This ensures permanent protection of the at least one coil in the holder, in particular against environmental influences, e.g. B. allows weather influences.

The mount can be made of an electrically non-conductive material, in particular plastic. Plastic enables magnetic fields to be measured around a current-carrying conductor with a coil without measuring errors or falsifications.

The at least one coil can be circular, and the at least one current-carrying conductor can be arranged in the center of the circular shape, in particular with its longitudinal axis perpendicular to the plane of the circle. Precise positioning of the coil around the current-carrying conductor, in particular constant over time in a groove, with the current-carrying conductor at the center of the circular shape of the coil, enables error-free measurement and determination of the current flowing through the current-carrying conductor.

The encapsulating housing can include aluminum and/or consist of aluminum. Aluminum does not or only slightly falsifies magnetic fields of the current-carrying conductor, which enables an error-free or essentially error-free measurement of the current through the current-carrying conductor, via the magnetic field generated around the conductor and by the current induced in the coil through the field, with a coil outside the encapsulating case.

The at least one coil can consist of a sheathed electrical conductor, in particular a copper conductor, in particular with a sheath made of electrically non-conductive plastic. Such sheathed conductors, i. H. Lines or cables are simple and inexpensive to form or wind into a coil. Copper conductor coils are well suited for electrical measurements, especially induced currents.

The at least one coil can be wound on a carrier, in particular a carrier made of electrically non-conductive material, in particular paper, plastic and/or Teflon. Winding on a carrier is inexpensive and easy, and the carrier gives the winding a permanent mechanical hold. Paper, plastic and/or Teflon supports do not falsify induction and measurements of currents induced in conductors. This makes them well suited for use in current transformers with coils without a magnetic core.

Auxiliary units, in particular at least one evaluation unit, an amplifier, and/or a power supply can be included in the current transformer according to the invention, in particular arranged in a housing in the form of a box and/or a cabinet, in particular arranged on and/or near the encapsulating housing, in particular with at least one cable connection of the at least one coil to the auxiliary units.

The auxiliary units enable a measurement using the coil and an evaluation, display and/or transmission of measurement results. The arrangement in a housing outside the encapsulating housing enables simple, trouble-free evaluation and reading as well as transmission of measurement results, as well as easy maintenance of the auxiliary units.

An encapsulated high-voltage device according to the invention comprises at least one current transformer as described above, in particular arranged outside of an encapsulating housing which is gas-tight and/or is filled with a switching gas, in particular SF ₆ and/or clean air.

A high voltage circuit breaker may be included in the high voltage enclosure be, which can be connected by the at least one current-carrying conductor in particular to power generators, power consumers and / or power lines of a power grid.

The encapsulated high-voltage device can be in the form of a gas-insulated switchgear, in particular a dead-tank gas-insulated switchgear.

The advantages of the encapsulated high-voltage device according to claim 12 are analogous to the previously described advantages of the current transformer according to the invention for encapsulated high-voltage devices according to claim 1 and vice versa.

In the following, an exemplary embodiment of the invention is illustrated schematically in the figures and described in more detail below.

• 1 schematisch ein gekapseltes Hochspannungsgerät 1 mit einem stromdurchflossenen Leiter in einem Kapselungsgehäuse 5, an welchem ein Stromwandler 9 nach dem Stand der Technik mit einem Ringkern mit Sekundärwicklung und ein erfindungsgemäßer Stromwandler 2 mit einer magnetkernlosen Luftspule angeordnet sind, und
• 2 den Stromwandler 2 der 1 vergrößert dargestellt, mit einer Halterung 6 der magnetkernlosen Luftspule mit Abdeckung 8 am Kapselungsgehäuse 5 angeordnet, und
• 3 den Stromwandler 2 der 2, mit der Halterung 6 ohne Abdeckung 8 und der Spule 3 in einer Nut 7 angeordnet.

The show

• 1 schematically shows an encapsulated high-voltage device 1 with a current-carrying conductor in an encapsulating housing 5, on which a current transformer 9 according to the prior art with a toroidal core with secondary winding and a current transformer 2 according to the invention with an air coil without a magnetic core are arranged, and
• 2 the current transformer 2 of 1 shown enlarged, arranged with a holder 6 of the air coil without a magnetic core with a cover 8 on the encapsulating housing 5, and
• 3 the current transformer 2 of 2 , arranged with the holder 6 without cover 8 and the coil 3 in a groove 7.

In 1 an encapsulated high-voltage device 1 with an encapsulating housing 5 is shown schematically. The high-voltage device 1 is z. B. designed as a switchgear, with a high-voltage circuit breaker inside the encapsulating housing 5. The switchgear is designed in particular as a dead-tank gas-insulated switchgear, ie gas-insulated switchgear, with the high-voltage circuit breaker or the switching unit in a grounded housing . The high-voltage device 1 is z. B. designed for voltages in a two-digit kilovolt range up to a voltage range of a few hundred kilovolts, in particular 1200 kV, and for currents in the range of up to a few hundred kiloamperes.

The encapsulating housing 5 is z. B. in the form of a kettle and z. B. aluminum. Two bushings for current-carrying conductors or connections with connection lugs for electrical power generators, consumers and/or mains lines are arranged on the encapsulating housing 5 , in particular led away from the encapsulating housing 5 upwards at an oblique angle. The current-carrying conductors are arranged inside the bushings, and in the external view of the 1 not shown. The implementations are z. B. made of ceramic, silicone and / or a composite material. The current-carrying conductors connect z. B. the high-voltage circuit breaker inside the encapsulating housing 5 electrically with the terminal lugs for the electrical power generator, consumer and / or power lines.

The encapsulating housing 5 is z. B. arranged on two mechanically stable supports, in particular two ladder-shaped metal frames, which on a foundation, z. B. concrete, are arranged. A current transformer 9 according to the prior art, with a toroidal core with a secondary winding, is arranged on the periphery of a bushing or around a bushing, in 1 shown on the right side of the encapsulating housing 5. The current transformer 9 with toroidal core and secondary winding is z. B. formed as an inductive plug-in current transformer. The toroidal core is made of high-quality sheet metal with high permeability and is provided with an appropriate secondary winding. The toroidal core made of laminations leads to a spatially voluminous design of the current transformer 9, with a high weight, and requires a solid design with high mechanical stability in order to withstand loads which are caused by high currents or magnetic fields.

A current transformer 2 according to the invention with an air coil without a magnetic core is in 1 shown on the left side of the encapsulation housing 5, adjacent to the bushing on the left side. In the 2 and 3 the arrangement of the current transformer 2 according to the invention on the encapsulating housing 5 is enlarged, shown in detail. The current-carrying conductor 4 inside the bushings, which projects into the encapsulating housing 5 or runs in the encapsulating housing 5, is in the 2 and 3 shown dashed. The head 4 is z. B. rod-shaped and / or rail-shaped, in particular solid copper, aluminum and / or steel. The conductors 4, which lead from the connection lugs for electrical power generators, consumers and / or power lines to the high-voltage switching device or the switching unit inside the encapsulating housing 5, and connect the switching unit to the power supply and / or devices in the network are z. B. current flows when the switching unit is switched on, with currents in the range of up to a few hundred amperes.

The currents generate a magnetic field which the encapsulating housing 5, in particular Aluminum penetrates and is measured by the current transformer 2 according to the invention, by induction of current in a magnetic coreless coil 3 of the current transformer 2. The current transformer 2 thus measures the current via a conductor 4 in the encapsulating housing 5 or via the switching unit. This is necessary for safe, trouble-free operation, e.g. B. the switching unit and / or connected devices and the network necessary. The state of the switching unit and its trouble-free function can be determined in this way and, in particular with critical currents, z. B. take place a shutdown.

The encapsulating housing 5 of the high-voltage device 1 has a flange at the connection point for feeding through the conductor 4, in particular a hollow-cylindrical flange as an opening in the encapsulating housing 5. The current transformer 2 according to the invention with an air coil without a magnetic core is arranged on the outside in a circle around the flange. The current transformer 2 has a holder 6 in which the coil 3 is arranged. In 2 the holder 6 is shown with a cover 8, which covers the coil 6 and against environmental influences such. B. moisture, UV radiation and / or other weather conditions protects. The holder 6 with the cover 8 encapsulates the coil 3 in particular completely, e.g. B. waterproof.

In 3 the holder 6 is shown without the cover 8. The holder 6 is ring-shaped, in particular circular in shape, and has a groove 7, ie a particularly annular recess in the holder 6. The coil 6 without a magnet core is arranged in the groove 7, in particular mounted in a spatially fixed manner. The spatial fixation of the coil 3 in the holder 6 with groove 7 enables an error-free measurement of currents in the current-carrying conductor 4 with the help of the coil 4. By fixing the coil 3 in the groove 7 of the holder 6, the coil is stored unchanged in terms of space and time , Even with large forces on the coil 3 in particular by magnetic fields and in the coil 3 induced currents.

The holder 6 and thus the coil 3 in the groove 7 of the holder 6 are arranged around the current-carrying conductor such that when the coil 3 is circular, the current-carrying conductor 4 penetrates with its longitudinal axis perpendicularly the plane of the coil 3, in particular in the center of the circular shape of the Coil 3. This enables a permanently error-free, precise measurement of the currents. The bracket 6 and / or the cover 8 are z. B. made of plastic, and fastening means such. B. screws and / or clamps on the encapsulating housing 5 temporally unchangeable and spatially stable. The coil 3 without a magnetic core is designed in particular in the manner of a Rogowski coil. The coil 3 is connected in particular to auxiliary units, e.g. B. an evaluation unit, an amplifier, and / or a power supply, which are not shown for the sake of simplicity in the figures. With the aid of the auxiliary units, the currents induced in the coil 3 can be measured, evaluated, displayed and/or sent to other devices, such as B. to a central control room, sense boxes, and / or decentralized handheld devices such. e.g. laptops, tablets, and/or cell phones.

Like in the 1 is illustrated, a current transformer 2 according to the invention with a coil 3 without a magnetic core, in particular with a holder 6 and cover 8, is spatially much smaller than a current transformer 9 according to the prior art with a toroidal core with a secondary winding, in particular in an associated housing, is lighter in terms of weight, and enables permanent, reliable, error-free measurement of the currents through a current-carrying conductor 4, arranged in the encapsulation housing 5, of the encapsulated high-voltage device 1 according to the invention.

The exemplary embodiments described above can be combined with one another and/or can be combined with the prior art. So e.g. as in 1 is shown, classic current transformers 9 according to the prior art with a toroidal core with secondary winding and current transformers 2 according to the invention with a coil 3 without a magnetic core, in particular a Rogowski coil, are used on an encapsulated high-voltage device 1, in particular used simultaneously. The high-voltage device 1 is or includes z. a high voltage circuit breaker, isolator, arrester and/or bushing for high voltage, and/or may be used in medium voltage applications. The high-voltage device 1 is z. B. designed as an outdoor switchgear and / or as a gas-insulated switchgear. The execution is z. B. as a live tank, arranged with a switching unit in an isolator, such as. B. in a ribbed ceramic, silicone and / or composite material insulator housing, or as a dead tank, ie arranged with a switching unit in a grounded housing, in particular a housing in the form of a kettle. The coil 3 includes z. B. a particular sheathed copper cable, and / or cables made of electrically conductive materials such. As aluminum and / or steel, or superconductors. The bracket 6 and / or the cover 8 are z. B. made of plastic, and / or include ceramic, silicone and / or composite materials.

Reference List

1

encapsulated high-voltage device

2

Current transformer with an air coil without a magnetic core

3

coil without a magnetic core

4

current-carrying conductor

5

encapsulation housing

6

bracket

7

groove

8th

cover

9

Current transformer with toroidal core

Claims (14)

Current transformer (2) for encapsulated high-voltage devices (1), with at least one coil (3), which is arranged around at least one current-carrying conductor (4), wherein the at least one current-carrying conductor (4) is arranged in an encapsulating housing (5), characterized characterized in that the at least one coil (3) is an air coil without a magnetic core. Current transformer (2) after claim 1 , characterized in that the air-core coil without a magnetic core is designed in the manner of a Rogowski coil. Current transformer (2) according to one of the preceding claims, characterized in that the at least one coil (3) is arranged outside the encapsulating housing (5). Current transformer (2) according to one of the preceding claims, characterized in that the at least one coil (3) is arranged in a holder (6), in particular in a groove (7) which is formed in the holder (6). Current transformer (2) after claim 4 , characterized in that the holder (6) comprises a cover (8) which in particular completely covers the at least one coil (3). Current transformer (2) according to one of Claims 4 or 5 , characterized in that the holder (6) consists of an electrically non-conductive material, in particular plastic. Current transformer (2) according to one of the preceding claims, characterized in that the at least one coil (3) is of circular design and the at least one current-carrying conductor (4) is arranged in the center of the circular shape. Current transformer (2) according to one of the preceding claims, characterized in that the encapsulating housing (5) comprises aluminum and/or consists of aluminum. Current transformer (2) according to one of the preceding claims, characterized in that the at least one coil (3) consists of a sheathed electrical conductor, in particular a copper conductor, in particular with a sheath made of electrically non-conductive plastic. Current transformer (2) according to one of the preceding claims, characterized in that the at least one coil (3) is wound on a carrier, in particular a carrier made of electrically non-conductive material, in particular paper, plastic and/or Teflon. Current transformer (2) according to one of the preceding claims, characterized in that auxiliary units, in particular at least one evaluation unit, an amplifier and/or a voltage supply, are included, in particular arranged in a housing in the form of a box and/or a cabinet, in particular arranged on and/or near the encapsulating housing (5), in particular with at least one cable connection of the at least one coil (3) to the auxiliary units. Encapsulated high-voltage device (1), characterized in that the encapsulated high-voltage device (1) has at least one current transformer (2) according to one of the preceding claims, in particular arranged outside an encapsulating housing (5) which is designed to be gas-tight and/or with a switching gas, in particular SF ₆ and/or Clean Air, is filled. Encapsulated high-voltage device (1) after claim 12 , characterized in that a high-voltage circuit breaker is included, which is connected by the at least one current-carrying conductor (4) in particular to power generators, power consumers and / or power lines of a power grid. Encapsulated high-voltage device (1) according to one of Claims 12 or 13 , characterized in that the encapsulated high-voltage device (1) is in the manner of a gas-insulated switchgear, in particular a dead-tank gas-insulated switchgear.

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