EP3561845A1 - Vacuum circuit breaker tubes - Google Patents

Abstract

The invention relates to a vacuum circuit breaker tube with a moving contact (4) and a fixed contact (6), each having at least one contact surface (8) and with a contact pin (10) which is coupled on the one hand with a drive unit and on the other hand with the moving contact ( 4) is mechanically coupled, characterized in that the contact pin is further mechanically coupled to a Vorzündkontakt (14) and the Vorzündkontakt is mounted independently of the moving contact (4) along a switching axis (16) translationally movable.

Description

The invention relates to a vacuum circuit breaker tube according to the preamble of claim 1.

In the case of different systems for increasing or controlling the transmission power of high-voltage networks, such as Fixed Series Capacitors (FSCs) or Universal Flow Flow Controllers (UPFCs or APCUs), protective devices must be installed in the event of a network fault, for example in the case of a short-circuit or ground fault, be provided. The protection consists of a surge arrester and a bypass or short-circuit current path, which is electrically closed when a mains failure occurs. Decisive for the protective effect is the fastest possible reaction in the event of a power failure. Typically, the bypass current path should be closed within two milliseconds ms and subsequently carry the resulting fault current over a period of a few seconds.

According to the prior art, power semiconductors or a combination of a spark gap, a so-called spark gap and circuit breakers are usually used for the described exemplary applications. Power semiconductors are comparatively expensive because they have to be designed for the short-circuit current over a comparatively long time for them. The also applied parallel arrangement of a spark gap and a circuit breaker, however, requires a very large amount of space. In addition, the Spark Gap is vulnerable to environmental influences such as icing or dust due to its open design.

The object of the invention is to provide a mechanical switch which, in the event of a short circuit can very quickly make electrical contact and is inexpensive to produce compared to the known switching devices and is less prone to environmental influences.

The solution of the problem consists in a vacuum circuit breaker tube having the feature of claim 1.

The vacuum circuit breaker tube according to claim 1 comprises a moving contact and a fixed contact each having at least one contact surface. Further, the circuit breaker tube comprises a contact pin which is coupled on the one hand with a drive unit and on the other hand is mechanically coupled to the moving contact. The term mechanically coupled is understood to mean that said components can be brought into operative connection, so that forces such as tensile, compressive or bending forces can be transmitted in a static and / or dynamic manner, from which movements can result. The invention is characterized in that the contact bolt is further mechanically coupled to a pre-ignition contact (14) and that the pre-ignition contact is mounted so as to be translationally movable independently of the moving contact (4) along a switching axis (16).

This means that compared to a vacuum circuit breaker tube of the prior art, a second contact system with a Vorzündkontakt is present, which is independently movable relative to the actual moving contact at least over a certain distance, but which is also very fast compared to conventional moving contacts, so that after a translational movement, an arc is formed between the pre-ignition contact and a counterpart of the pre-ignition contact, which together form a pre-ignition contact system, even before the occurrence of a permanent mechanical contact. This arc is able to carry a current and maintain it for a few milliseconds until the moving contact is brought together with the fixed contact and a permanent contact of the permanently one Carries electricity, is trained. Once the permanent contact is formed, the arc goes out. It is thus a fast Vorzündsystem compared to conventional vacuum circuit breaker tubes or gas-insulated circuit breakers extremely close a circuit before the main circuit or the continuous circuit is closed. An overload of sensitive network components can be avoided by the application of the vacuum circuit breaker tube described. Furthermore, it is possible to dispense with the so-called spark gap, which, for example, in the protection of compensation systems, means a significant saving in installation space. Furthermore, the disclosed vacuum circuit breaker tube is significantly less sensitive to environmental influences than a prior art switch combination.

In one embodiment of the invention, the Vorzündkontakt on a push rod which is mounted translationally movable along the indexing axis. The push rod is guided through a hole in a contact bottom of the moving contact. This makes it possible to move the Vorzündkontakt very quickly from the recess of the moving contact out. The push rod is coupled to the contact pin and can also be designed as part of the contact pin. That is, the push rod and the contact pin may be formed as a one-piece component

In a further embodiment of the invention, the contact pin along the indexing axis is movably mounted in such a way that in a closing movement in a first step, a mechanical coupling with the push rod of the Vorzündkontaktes. This mechanical coupling results in a translational movement along the indexing axis. The Vorzündkontakt with its push rod is thus first moved by the contact pin along the indexing axis in the direction of the fixed contact. Only in a second step also takes place with the contact pin mechanical coupling with the moving contact. The likewise to a translational movement along the switching axis result and eventually to build a permanent contact, which is permanently energized leads. The advantage in this specific embodiment is that first the entire drive energy is focused on the relatively light Vorzündkontakt, so that it can move very quickly in the direction of the moving contact and a counterpart in moving contact and can quickly generate the arc. Only in a second step, if there is already a current conduction or shortly before, the relatively sluggish and heavy moving contact is set in motion and thus made the permanent contact. As long as this movement takes place and the structure of the permanent contact has not yet been completed, the current flow takes place along an arc current path, which withstands for a sufficient time until the permanent contact has a current carrying capacity.

For an effective equipotential bonding between the moving contact and the Vorzündkontakt or between the arc current path and the continuous current path, it is expedient if the moving contact and the Vorzündkontakt are electrically connected to each other. This can be done for example by a sliding contact or by an electrically conductive radial bearing or by a pressing together.

The contact pin is provided in one embodiment of the invention with a driving device or it is in operative connection with this. This is suitable during a translational movement of the contact pin along the switching axis, in which initially only the Vorzündkontakt is moved to intervene in a further course in the moving contact, whereupon this also performs a translational movement along the indexing axis.

In a further embodiment of the invention, a closing movement of the circuit breaker in the direction of gravity F _g. When the switch is triggered, an acceleration of the contact pin takes place and thus the push rod of the pre-ignition contact with a medium acceleration, which is at least eight times the gravitational acceleration, preferably thirty times the gravitational acceleration. The inertia of the moving contact due to the relatively low gravitational acceleration leads to a delay of the movement relative to the Vorzündkontakt. This can be enhanced by applying a very high acceleration to a relatively low mass of the Vorzündkontaktes, resulting in a much faster movement of the Vorzündkontaktes. This high acceleration of the Vorzündkontaktes it is possible, already after a few milliseconds in which moves the Vorzündkontakt relative to the moving contact in the direction of fixed contact to build an arc between the Vorzündkontakt and its counterpart in the fixed contact and thus provide a current path, namely the arc current path.

In principle, it is possible for the continuous current path and the arc current path to follow the same geometric path. When forming an arc, however, a melting occurs at the surface, so that welding may occur at a later contacting of the permanent contact at these points, which can lead to surface roughness when the contact is re-dissolved. These in turn could negatively affect the electric field. For this reason, it is expedient to separate the continuous current path and arc current path geometrically, at least in the area of the contact surfaces.

Another part of the invention is a use of a vacuum circuit breaker according to one of claims 1 to 9 for a short-circuiting device for shorting a circuit and thus to protect a network interference system from an overvoltage. In this context, a network-influencing system is understood as meaning, for example, a series-compensation system or a unified power-flow regulator. Both are systems that are used to influence a power grid, which in the event of a short circuit, are switched off or de-energized within a very short time must be in order to avoid damage to these systems. A described switch is particularly well suited due to its rapid development of an arc current path to disconnect a network influencing system very quickly from the mains and thus to prevent their damage.

Further embodiments of the invention and further features will be explained in more detail with reference to the following figures. Features with the same name but in different embodiments have the same reference numerals. This also applies to the drawing, which reflects the state of the art. The illustrated embodiments are schematic embodiments that do not limit the scope of protection.

Showing:

FIG. 1

a vacuum circuit breaker tube according to the prior art,

FIG. 2

a vacuum circuit breaker tube with a pre-ignition contact,

FIG. 3

the vacuum circuit breaker tube according to FIG. 2 with advanced pre-ignition contact on built-up arc,

FIG. 4

a closed circuit breaker tube according to FIGS. 2 and 3 with a continuous current path,

FIG. 5

the circuit breaker tube according to FIG. 4 with closed permanent contact and already reopened pre-ignition contact and

FIG. 6

the vacuum circuit breaker tube according to FIG. 5 in reopened position, analogous to the illustration in FIG. 2

FIG. 7

a vacuum circuit breaker tube in which the closing movement of the moving contact in the direction of gravitational force,

FIG. 8

the vacuum circuit breaker tube according to FIG. 7 with pre-ignition contact already built up and built-up arc,

FIG. 9

the vacuum circuit breaker tube according to FIG. 8 with closed moving contact and continuous current path and

FIG. 10

a vacuum circuit breaker tube according to FIG. 7 with a driving device on the push rod of Vorzündkontaktes to entrain the moving contact during the closing process

In the FIG. 1 there is shown a vacuum circuit breaker tube 2, which schematically corresponds to a vacuum circuit breaker tube 2 of the prior art. This vacuum circuit breaker tube 2 has two contacts, a moving contact 4 and a fixed contact 6. The two contacts 4, 6 each have a contact surface 8, wherein the contact surfaces 8 of the contacts 4, 6 are in a closed state to each other and this a current flow is guaranteed. Furthermore, the described contact system of moving contact 4 and fixed contact 6 is arranged in a vacuum-tight housing 44 that has insulators 36 in certain areas. In the area in which the contacts 4, 6 meet, typically a vapor shield 38 is arranged. Furthermore, the circuit breaker tube 2 has a contact pin 10, which is guided in a vacuum-tight manner in the housing 44 and is movably supported via a so-called bellows 40. Since this is a vacuum switch, in the housing 44 is a vacuum (negative pressure to atmospheric pressure), in particular a high vacuum (a pressure of less than 10 ^-3 hPa) before. In contrast to gas-insulated switches, there is no insulating gas or extinguishing gas in the housing 44.

In FIG. 2 a vacuum circuit breaker tube 2 is shown, which is opposite to the circuit breaker tube 2 in FIG. 1 is modified. The circuit breaker tube 2 according to FIG. 2 Also comprises two contacts, a moving contact 4 and a fixed contact 6, these contacts are designed pot-shaped seen from the cross section, which means that they have a recess 12 in its center. In the recess 12 of the moving contact 4 Vorzündkontakt 14 is arranged. This Vorzündkontakt 14 has a counterpart 42 in the fixed contact 6, which in a closed state, compare FIG. 4 , engages in the pre-ignition contact 14. The Vorzündkontakt 14 preferably does not touch the counterpart 42 to avoid welding.

The Vorzündkontakt 14 is connected to a push rod 18 which is introduced through a bore 20 in the contact bottom 22 of the pot-shaped moving contact 4 and is movably mounted there along a switching axis 16. Further, the circuit breaker tube comprises a torque tube 28 which is mechanically coupled by a driver 48 on the contact pin 10 or on the push rod 18 to the movement of the contact pin 10. By this coupling, the translational movement of the moving contact 4 is now effected in the direction of the fixed contact 6.

First, the contact pin 10 moves in FIG. 2 in the view shown upwards, which means in this representation against gravity. It is first moved by the contact pin 10 of the Vorzündkontakt 14, it being noted that the Vorzündkontakt 14 has a much lower mass than the system of the moving contact 4 and the torque tube 28. Thus, the Vorzündkontakt 14 moves in the direction of its counterpart 42 wherein as in FIG. 3 shown, the emergence of the Vorzündkontakt 14 from a shielding effect of the moving contact 4 and the recess 12, an arc 30 ignites. This movement takes place with a suitable setting in a few milliseconds. So it is possible that after about 1 - 3 milliseconds, an arc current path 32 for conducting an electric current through the arc 30 through the circuit breaker tube. For this purpose, corresponding fast drives are preferred bounce-free drive advantageous, which are not shown here, but are known from the prior art. These in turn can ensure a movement of the Vorzündkontaktes 14 and a formation of the arc 30 in the said time ranges. A bounce-free drive can be achieved, in particular, by temporarily storing the kinetic energy of the moving contact on impact with the fixed contact in a spring device (not shown here) of the drive unit (hereunder mechanical springs or gas pressure springs).

In FIG. 4 Now the next step is shown. The contact pin 10 or the entrainment device 48 has now reached the torque tube 28 in its translational movement and pushed the moving contact 4 in the direction of the fixed contact 6, so that the contact surfaces 8 of the contacts 4 and 6 are superimposed and there is a flow of a continuous current , Depending on the application of the circuit breaker tube 2 and depending on the operating situations, faults or short-circuit currents can also flow via the continuous current path 34. In FIG. 4 is a Dauerstrompfad provided with the reference numeral 34. FIG. 5 shows a step of the opening movement of the circuit breaker tube 2, wherein it can be seen that in a first step the pre-ignition contact 14 with the push rod 18 is withdrawn, in which phase the continuous current path 34 remains and only in a second step Permanent current path 34 is released by opening the moving contact 4. (see FIG. 6 ). Furthermore, a sliding contact, not shown here, is preferably provided, which provides an electrical connection between the pre-ignition contact 14 and the moving contact 4 and thus serves to equipotential bonding between these two contacts 4, 14.

In the Figures 7-10 is given a reverse orientation from the previous figures known vacuum circuit breaker tube 2. The main difference between the vacuum circuit breaker tube 2 from the Figures 2-6 and the Circuit breaker tube 2 from the Figures 7-10 is that in the Figures 7-10 the moving contact 4 is arranged above and the switching direction along the gravity F _g , indicated by arrow F _g in FIG. 7 he follows. In this way, the gravity F _{g is used to} support the closing movement. An alignment along gravity means that the circuit breaker tube 2 and thus especially the switching axis 16 in the direction of gravity F _{g is} aligned, but this also means that the switch tube 2 and the switching axis 16 must be aligned so that at least one force component the force of gravity acts in the direction of the switching axis of the moving contact 4.

Another difference of the vacuum circuit breaker tube 2 according to FIG. 7 opposite to the FIG. 2 is that can be dispensed with a torque tube 28, the function of the torque tube 28 can by the contact pin 10, as in FIG. 7 seen or by an additional driver 48, as in FIG. 10 is shown completed. The contact pin 10 is in direct contact with the push rod 18 of the Vorzündkontaktes 14 of the analogous to that FIG. 2 is stored in moving contact. In FIG. 8 is shown as the Vorzündkontakt 14 is moved out of the moving contact 4 and thereby ignites an arc 30. It should be noted that the acceleration of the Vorzündkontaktes 14 must be relatively high for rapid formation of the arc 30, it should be at least eight times the gravitational acceleration, in a preferred embodiment, the acceleration of the contact pin 10 and thus the Vorzündkontaktes 14, about thirty times the Acceleration of gravity. In FIG. 9 is now analogous to FIG. 4 the circuit breaker tube 2 shown in a closed state, wherein the permanent current-carrying continuous current path 34 has formed.

LIST OF REFERENCE NUMBERS

2

Vacuum circuit breaker tube

4

moving contact

6

fixed contact

8th

contact area

10

Contact pin

12

deepening

14

Vorzündkontakt

16

switching axis

18

pushrod

20

drilling

22

Contact floor

28

torque tube

30

Electric arc

32

Arc current path

34

Continuous current path

36

insulator

38

vapor shield

40

bellow

42

Counterpart pre-ignition contact

44

casing

46

umbrella

48

entraining

Claims (9)

Vacuum circuit breaker tube with a moving contact (4) and a fixed contact (6), each having at least one contact surface (8) and with a contact pin (10) which is coupled on the one hand with a drive unit and on the other hand with the moving contact (4) mechanically coupled is, characterized in that the contact pin is further mechanically coupled to a Vorzündkontakt (14) and the Vorzündkontakt is mounted independently of the moving contact (4) along a switching axis (16) translationally movable. Vacuum circuit breaker tube according to claim 1, characterized in that the Vorzündkontakt comprises a push rod (18) which is mounted translationally movable along the indexing axis (16) and by a bore (20) in a contact bottom (22) of the moving contact (4). is guided. Vacuum circuit breaker tube according to claim 1 or 2, characterized in that the contact pin (10) along the indexing axis (16) is movably mounted in such a way that during a closing movement in a first step, a mechanical coupling with the push rod (18), which results in a translatory movement along the switching axis (16) and in a second step, a mechanical coupling with the moving contact (4), which also results in a translational movement along the switching axis. Vacuum circuit breaker tube according to one of the preceding claims, characterized in that the moving contact (4) and the Vorzündkontakt (14) are electrically connected to each other for equipotential bonding. Vacuum circuit breaker tube according to claim 4, characterized in that the moving contact (4) and the Vorzündkontakt (14) by a sliding contact (24) are interconnected. Vacuum circuit breaker tube according to one of the preceding claims, characterized in that a driving device is provided on the contact pin, which can be brought into mechanical engagement with the moving contact. Vacuum circuit breaker tube according to one of the preceding claims, characterized in that a closing movement of the circuit breaker in the direction of gravity F _g takes place and an acceleration a of the contact pin (10) and thus the push rod (18) of the Vorzündkontaktes (14) takes place with a value, which is at least eight times the gravitational acceleration, preferably thirty times. Vacuum circuit breaker tube according to one of the preceding claims, characterized in that an arc current path (32) and a continuous current path (34) extend at least partially geometrically separated from each other. Use of a vacuum power circuit breaker according to one of claims 1 to 8 for a short-circuiting device for short-circuiting a circuit and thus protecting a network influencing system from an overvoltage.

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