CN110622269B

CN110622269B - Mechanical switching device for current interruption

Info

Publication number: CN110622269B
Application number: CN201880029212.9A
Authority: CN
Inventors: P.G.尼科利奇; S.科斯; C.沙赫雷尔
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2017-05-03
Filing date: 2018-04-25
Publication date: 2021-12-24
Anticipated expiration: 2038-04-25
Also published as: WO2018202506A1; CN110622269A; DE102017207426A1; EP3602591A1

Abstract

The invention relates to a mechanical switching device for current interruption, comprising at least two switching contacts (4, 6) which are arranged so as to be movable in translation relative to one another along a switching path (8) which is an integral part of a switch housing (10). The invention is characterized in that the switch housing (10) is provided with a closure (12) with an aperture, wherein the aperture (14) forms part of the switch path (8), and wherein the closure (12) is supported in the switch housing (10) such that the aperture (14) can be screwed out of the switch path (8).

Description

Mechanical switching device for current interruption

Technical Field

The invention relates to a mechanical switching device for interrupting current according to the invention and to a method for operating a switching device according to the invention.

Background

In order to interrupt direct currents and for current-limiting switches, in particular in direct current systems, but also for alternating current systems, efficient and low-cost switching devices are required to interrupt or limit fault currents.

In order to interrupt the direct current, also referred to as DC current, semiconductor switches are used today in high voltage primarily, or alternating current switches are equipped with additional circuits or design measures for generating artificial zero crossings. In principle, high direct currents are more difficult to switch off than high alternating currents. This is because the direct current has no zero-crossing and therefore there is a continuous arc between the contacts to be separated.

Solutions for interrupting such arcs in direct current switches are complex and costly in design and are limited to a certain extent, in particular for high fault currents, in terms of the achievable switching speeds. For example, circuit breakers are used in railway technology for dc applications, in which circuit breakers arc-extinguishing lamination stacks are used

To increase the voltage drop over the switching arc and thus to build up a counter voltage to interrupt the direct current. Due to the relatively slow response time of this switching principle, the extremely large fault current increase in dc systems results in the switches having to be designed for very high fault currents.

Disclosure of Invention

The object of the present invention is to provide a mechanical switching device for interrupting current and a suitable method which ensure faster switching times and higher reverse voltages than the prior art and by means of which current limiting can also be achieved.

The solution to this problem is a mechanical switching device according to the invention for interrupting a current and a method according to the invention for operating a switching device.

The switching device according to the invention for current interruption comprises at least two switching contacts which can be moved in translation along a switching path. The switching path is a part of a switch housing in which the switching contacts are arranged. The switching device is further characterized in that the switch housing is provided with a closure with a bore, wherein the bore in turn forms part of the switching path in the basic position. The invention is further characterized in that the closure is supported in the switch housing such that the opening can be rotated out of the switching path from the basic position. The term switching path is understood here to mean an elongated three-dimensional cavity which is ideally cylindrical in design but in practice takes a significantly more complex shape in the switching device, which is determined by other technical requirements.

The switching path is interrupted particularly quickly and efficiently by unscrewing the hole out of the switching path. When the switch contacts are separated, the switching arc, which is formed in particular in the direct current circuit, is interrupted by the tap hole and thus by the blocking of the switching path. This rotational movement can be carried out particularly quickly, so that a quick opening operation is ensured. It is furthermore possible that the nature of the rotational movement of the closure and the bore does not lead to a complete interruption of the switching arc, but only to a reduction of the bore cross section. In this case, the switching arc is still present, but in a constricted form, thereby greatly increasing the voltage requirement at this location of the hole and thus the current-limiting effect of the switch. In this way, the described switch can be used both as a disconnector, in particular for dc applications, and as a current limiter in dc and ac applications.

In particular in the range above 1000V, in particular in the low, medium or high-voltage range, but also in the partial range of low voltages, the switching device described can advantageously be used.

In a further embodiment of the invention, a plurality of openings can be provided for each closure element, and therefore a plurality of switching contacts to be separated can be provided. A plurality is to be understood in particular as one, two or three bores, so that in practice, usually three-pole switches with a single closure element with a centrally controlled rotary motion can also be used to interrupt the current.

A further component of the invention is a method for operating a switching device, in which two switching contacts in a switching path of a switch housing are moved in translation relative to one another in order to open an electrical circuit. The method is characterized in that a closure is provided, which has an opening which is rotated out of the switching path from the basic position during the switching process. This method has the same advantages as already listed in relation to the device according to the invention. In addition to switching high direct currents, the method is also suitable for describing the current limiting action for direct currents and alternating currents.

Drawings

Other designs and other features of the invention are described in more detail in the following figures. These are purely exemplary and do not limit the scope of the design. Features which have the same meaning and the same name but which are present in different design versions have the same reference numerals here.

In the drawings:

figure 1 shows a schematically drawn illustration of a switching device with separated switching contacts and a switching arc in an open switching path between the two contacts,

fig. 2 shows the same switching device as in fig. 1, with a rotating closure which causes a reduction in the cross section of the switching path, and thus a constriction of the switching arc,

fig. 3 shows a switching device as shown in fig. 1, with a switched-on switching path and separate switching contacts,

fig. 4 shows a plan view, also in a cross section through the switching device, rotated by 90 ° with respect to the cross sections in fig. 1 to 3, in this case the switching device has three switches and thus the current lines of the three poles are disconnected.

Detailed Description

Fig. 1 to 3 each show a schematic representation of a switching device 2, which is depicted in different switching states. The switching device according to fig. 1 has a schematically illustrated switch housing 10 in which the switching path 8 is arranged. In this illustration, the switching path is ideally reproduced and depicted in the form of a cylinder. In principle, the switching path 8 is considered to be a volume in which the switching contacts (here represented by the switching contacts 4 and 6) move in translation relative to one another. In many switching devices, one switching contact is fixedly arranged, while the other switching contact can be moved in a translatory manner relative to the switching contact. In these examples, the two

switch contacts

4 and 6 are mounted so as to be movable in translation relative to one another along a cylindrical axis 18.

If the two

switching contacts

4 and 6 are separated from one another and are located in the position shown in fig. 1 relative to one another, a switching arc 22 is formed, in particular in the case of switching Direct Current (DC). Since the direct current loop has no zero crossing of the voltage, the switching arc will exist for a long time or continuously if there is no other measure to extinguish the switching arc. For this purpose, a closure 12 with a bore 14 is arranged in the switch housing 10. The opening 14 is part of the switching path 8 in the basic position 1 according to fig. 1. The two

contacts

4 and 6 are guided through the opening 14 in their closed position, which is not shown here. In the open position of the two

switching contacts

4 and 6 shown in fig. 1, the

switching contacts

4 and 6 are not present in the bore 14.

Fig. 2 now shows a further position of the closure element 12, which is mounted so as to be pivotable in the direction of the arrow 16, so that the bore cross section 20 is reduced by a slight rotation of the closure element 12 and thus the fault arc 20 is constricted. Fig. 3 shows the next position of the closure element 12 (closure position 7), in which the switching path is interrupted. The hole 14 is here turned 90 ° with respect to fig. 1 and there is an obstacle between the

contacts

4 and 6. In principle, for an effective interruption, a closure rotation of less than 90 ° relative to the basic position is advantageous. In this region, the closure 12 preferably comprises an electrically insulating, temperature and radiation resistant, high-resistance material. For this purpose, high-temperature and radiation-resistant, high-resistance materials, in particular Polytetrafluoroethylene (PTFE) or ceramics, for example alumina or zirconia ceramics or graphite-based materials, are suitable.

In addition, the position of closure 12 in FIG. 2 will be discussed again. In the position of minimum design of the bore cross section 20 (limit position 9), the switching arc 22 is constricted. In this retracted restraint position, the switching arc 22 requires a significantly higher voltage for maintenance than in the case of the switching arc 22 according to fig. 1. On the other hand, this higher voltage requirement leads to a limitation of the current, so that the specific arrangement according to fig. 2 of the closing part 12 can also be used as a current limiter not only in direct current but also in alternating current. The described switching device is therefore on the one hand a switch for direct-current circuits and alternating-current circuits, wherein particular preference exists in the field of direct-current circuits. On the other hand, the arrangement is particularly well suited for use as a current limiter, especially for ac circuits.

In fig. 4, a representation different from that of fig. 1 to 3 is selected, with the difference that the cross section or the view of the switching device 2 in fig. 1 to 3 is rotated by 90 °. This is therefore also a cross section through the switching device 2, wherein this is a top view. Fig. 4 shows that the switching device 2 can also contain a plurality of switching contact pairs in addition to the switching

contacts

4 and 6 described in fig. 1 to 3. In this case, this is a three-pole design of the switching device 2, in which all three pairs of switching

contacts

4 and 6, 4 'and 6' and 4 ″ and 6 ″ can be separated from one another by the closure element 12. The closure 12 has three

openings

14, 14 'and 14 ″, by means of which the

switching paths

8, 8' and 8 ″, can be interrupted by a rotary movement 16 of the closure 12. In other words, the closing seal 12 can be moved by a single drive, not shown here, so that all three poles of the three-pole switch can be separated together. All the switch positions already described in fig. 1 to 3 can also be used here.

The invention makes it possible to realize a direct mechanical interruption of the direct current and of the current-limiting switches in direct current and alternating current systems by establishing a counter voltage. The counter voltage or voltage requirement of the arc can be set by the angle of rotation of the rotating obstacle. This is until the switching line can be completely interrupted by an obstacle 24, which is formed by the rotating aperture 14 or the closure element 12. The need for drive energy for the rotational movement of the closure 12 is greatly reduced by the rotation of the aperture or the obstruction 24 formed thereby. This allows for a shorter switching time compared to the prior art. The invention can be used for current interruption and current limiting switching in high, medium and low voltages and thus provides a flexible and scalable solution for such switchgear.

Claims

1. A mechanical switching device for current interruption, comprising at least two switching contacts (4, 6), the at least two switch contacts (4, 6) are arranged so as to be movable in translation relative to one another along a switch path (8), the switch path (8) being an integral part of a switch housing (10), wherein the switch housing (10) is provided with a cylindrical closure (12) with a bore, wherein the aperture (14) extends through the closure (12) and forms part of the switch path (8) in the on position, and wherein the closure (12) is supported in the switch housing (10) in such a way that, i.e. to enable the hole (14) to be unscrewed from the switch path (8), characterized in that, the switching device (2) is used for switching a direct current, and the switching path (8) is designed to have a cylindrical shape.

2. A switching device according to claim 1, characterized in that the switching device (2) is adapted to switch low, medium or high voltage.

3. A switching device according to claim 1, characterized in that the switching device (2) is adapted to switch on and off voltages higher than 1000V.

4. The switching device as claimed in one of claims 1 to 3, characterized in that the closure (12) is constructed with a cylindrical shape, the closure (12) having one, two or three bores (14, 14 ', 14 ") along a cylindrical axis (18), the bores (14, 14 ', 14") extending through one, two or three switching paths (8, 8 ', 8 "), and the bores (14, 14 ', 14") being jointly unscrewable from the switching paths (8, 8 ', 8 ") by a rotary motion of the closure (12).

5. A switching device according to any one of claims 1 to 3, wherein the material of the closure (12) in the region of the aperture (14) is polytetrafluoroethylene.

6. A switching device according to any one of claims 1 to 3, characterized in that the rotational movement (16) of the closure (12) can be carried out to such an extent that a reduced bore cross section (20) for constricting the switching arc (22) remains present.

7. A switching device according to claim 6, characterized in that the switching device is a current limiter.

8. A method for operating a switching device (2), in which two switching contacts (4, 6) in a switching path (8) of a switch housing (10) are moved in translation relative to one another for opening an electric circuit, characterized in that a cylindrical closure (12) is provided, which closure (12) has an aperture (14), which aperture (14) penetrates the closure (2) and is screwed out of the switching path (8) from an on position during switching.

9. Method according to claim 8, characterized in that the closure (12) is rotated such that the hole cross section is reduced and the switching arc (22) is constricted.