SINGLE-COLUMN DISCONNECTOR WITH VACUUM SWITCHING TUBE AS ADDITIONAL CONTACT SYSTEM

Description

[0001] The present invention relates to a switch arrangement for an air-insulated high-voltage disconnect switch comprising at least one main switch and one auxiliary switch, wherein the main switch comprises a single-column disconnect switch with at least one movable contact arm and a fixed mating contact piece; and the auxiliary switch comprises a vacuum switching chamber with an electrical switch and at least one actuating element arranged on the switch, wherein the vacuum switching chamber is arranged in an electrically conductive manner on the mating contact piece of the main switch;and wherein the electrical switch of the vacuum switching chamber is configured to establish or interrupt an electrically conductive connection between the opposite contact of the main switch and the movable contact arm of the main switch via the actuating element, wherein the actuating element of the vacuum switching chamber is arranged such that the electrical switch of the vacuum switching chamber closes before the main switch closes and opens after the main switch opens.

[0002] The safe and low-maintenance control of high currents or high voltages is increasingly important today, as the distances between the point of electricity generation and the point of consumption are constantly growing due to the energy transition. This results in ever-larger amounts of electricity being transmitted through the existing infrastructure, which significantly impacts the susceptibility of the entire system to faults. Therefore, safer and lower-maintenance individual components are becoming increasingly crucial. One way to visibly disconnect a current path in the high-voltage range, particularly in the range of up to 1200 kV, is through the use of single-column disconnect switches. A typical design of a single-column disconnect switch, as known, for example, from DE 33 07 606 A1 and EP O 104 599 A2, comprises at least one contact with a movable and a fixed contact element. This basic design has proven effective.

[0003] The design of various single-column disconnect switches is also discussed in patent literature.

[0004] For example, DE 10 2016 214 372 A1 describes a contact arm for a single-column disconnect switch, with at least one profile body and with at least one contact element, wherein the at least one profile body is rod-shaped and wherein the at least one contact element is rod-shaped, and wherein the contact element has a T-profile.

[0005] Furthermore, DE 3 412 449 A1 describes a contact system for high-voltage disconnect switches, in particular gripper disconnect switches, comprising a main contact piece, a counter-contact piece cooperating with it, and a pre-contact device arranged on the counter-contact piece, actuated by the main contact piece and intended for guiding an arc, which can be connected in parallel to these two contact pieces, is actuated by the main contact piece and is opened after the two contact pieces have opened and is closed before they have closed, wherein a part of the pre-contact device is electrically insulated from the counter-contact piece, and comprising a potential equalization contact device that can be connected in parallel to the pre-contact device in the off position.wherein the equipotential bonding contact device is formed by the mating contact piece and the movable switching pieces (14c) of the pre-contact device and that the main contact piece is galvanically isolated from the mating contact piece and its pre-contact device by a solid insulating medium provided in addition to the existing gaseous insulating material when the equipotential bonding contact device is closed.

[0006] However, such solutions known from the prior art can still offer further potential for improvement, particularly with regard to fault tolerance and wear resistance during operation. Circuit breakers with vacuum switching chambers are known from US 2012 / 048692 A1. DE 34 18 837 A1 i Another disconnect switch is known. Publication FR 2 693 837 A1 discloses a disconnect switch that corresponds to the preamble of claim 1.

[0007] The object of the present invention is to overcome, at least in part, the disadvantages known from the prior art. In particular, the object of the present invention is to provide a solution characterized by improved electrical wear resistance of the components during operation and which meets the increasing switching capacity requirements for disconnect switch types.

[0008] According to the invention, the problem is solved at least in part by a switch arrangement for an air-insulated high-voltage disconnect switch having the features of claim 1. Preferred embodiments of the invention are specified in the dependent claims, in the description or the figures, wherein further features described or shown in the dependent claims or in the description or the figures may, individually or in any combination, constitute an object of the invention unless the context clearly indicates otherwise.

[0009] The present invention thus relates to a switch arrangement for an air-insulated high-voltage disconnect switch comprising at least one main switch and one auxiliary switch, wherein the main switch comprises a single-column disconnect switch with at least one movable contact arm and one fixed mating contact; and The auxiliary switch comprises a vacuum switching chamber with an electrical switch and at least one actuating element arranged on the switch, wherein the vacuum switching chamber is arranged in an electrically conductive manner on the mating contact of the main switch; and wherein the electrical switch of the vacuum switching chamber is configured to establish or interrupt an electrically conductive connection between the mating contact of the main switch and the movable contact arm of the main switch via the actuating element, wherein the actuating element of the vacuum switching chamber is arranged such that the electrical switch of the vacuum switching chamber closes before the main switch closes and opens after the main switch opens.

[0010] Such an arrangement can offer significant advantages over solutions known from the prior art, as described in detail below. In particular, such an arrangement can increase the service life of the entire switching element and thus improve the fault tolerance of a power grid or high-voltage network. Specifically, the use of a vacuum switching chamber as part of the switching system makes it possible to reduce contact erosion by extinguishing arcs more quickly. Advantageously, the vacuum switching chamber can also be adapted to the specific switching tasks by selecting its individual components. The vacuum switching chamber controls the commutation currents in that it precedes the main switch when it closes, thus protecting the main switch.When the main switch opens, the vacuum switching chamber continues to operate, protecting the main contact by switching the commutation currents. This switching arrangement results in high uniformity of movement and an increase in the number of switchable commutation currents and voltages. Overall, this contributes to a highly reproducible switching process while protecting the main switch from excessively strong and uncontrolled electrical discharges.

[0011] The present switch assembly is suitable for an air-insulated high-voltage disconnect switch and comprises at least one main switch and one auxiliary switch. High-voltage switches are electrical switches for voltages above 1 kilovolt (kV), and the switch assembly is capable of ensuring both a virtually power-free disconnection of electrical system components and the switching on and off of high loads. The switch assembly includes at least two different electrical switches that can be either conductive or non-conductive, and in particular, the time of the change in electrical state can be changed independently of each other by both switching elements. Suitable specifications for the switch assembly include, for example, a voltage range of 36 kV to 800 kV and a current conductivity of up to 5000 A (80 kA - 1 s).The switch arrangement can, for example, conform to the specification according to IEC 62271-102.

[0012] The main switch of the switch assembly is a single-column disconnect switch comprising at least one movable contact arm and one fixed mating contact. The main switch is therefore a pantograph connected to the busbar by scissor arms. The pantograph enables a vertical disconnection path with a busbar connection and allows for both diagonal and parallel arrangements. The main switch is suitable for flexible and rigid busbars and can, for example, comply with the requirements of national and international standards such as IEC, ANSI, GOST R, and GB. The electrical contact is established via at least one movable contact arm, which can assume the states "disconnected from the mating contact" and "connected to the mating contact."

[0013] The auxiliary switch of the switch assembly is a vacuum switching chamber with an electrical switch and at least one actuating element arranged on the switch, wherein the vacuum switching chamber is electrically conductively connected to the mating contact of the main switch. The vacuum switching chamber is therefore a gas-insulated auxiliary switch which is permanently in electrically conductive contact with the mating contact of the main switch.

[0014] The electrical switch of the vacuum switching chamber is designed to establish or break an electrically conductive connection between the opposing contact of the main switch and the movable contact arm of the main switch via the actuating element. The vacuum switching chamber thus has an actuating element that mechanically interacts with the contact arm of the main switch and can be moved into either an electrically conductive or non-conductive position depending on the position of the contact arm. Likewise, if there is no mechanical contact between the contact arm of the main switch and the actuating element of the auxiliary switch, the switch can be in a non-conductive position.

[0015] The actuating element of the vacuum switching chamber is arranged such that the electrical switch of the vacuum switching chamber closes before the main switch closes. The actuating element thus moves "ahead" of the contact arm of the main switch due to its mechanical contact, and the electrical switch in the vacuum chamber closes, provided there is a corresponding mechanical actuation, before the main switch closes.

[0016] The actuating element of the vacuum switching chamber is arranged such that the electrical switch of the vacuum switching chamber opens after the main switch opens. If the mechanical actuation by the contact arm of the main switch fails, the auxiliary switch opens accordingly. The opening time is delayed after the opening of the main switch, so that a commutation current continues to flow through the vacuum switching chamber circuit even after the main switch has opened.

[0017] In a preferred embodiment of the switch arrangement, the main switch can comprise two movable contact arms and the auxiliary switch two actuating elements. An arrangement with two contact arms of the main switch has proven particularly suitable for achieving exceptionally smooth switching on and off of the currents. The two contact arms can move one or two independent actuating elements of the auxiliary switch. In this way, particularly smooth and reliable switching operations can be achieved.

[0018] In a preferred embodiment of the switch assembly, the vacuum switching chamber can be arranged on the mating contact of the main switch via a connecting piece made of steel or aluminum. This electrical connection solution with the mating contact of the main switch has proven to be particularly reliable and durable. The steel can be, in particular, stainless steel. Aluminum can be used preferentially in cases where the weight of the switch assembly is important.

[0019] Within a preferred aspect of the switch arrangement, the actuating element of the vacuum switching chamber can have at least a section of electrically insulated contact. The contact points of the actuating element of the vacuum switching chamber can be designed from materials appropriate to the contact system (moving contact points, e.g., silver-plated copper) or bridged by a flexible conductor that connects the long vertical lever to the pivot point of the vacuum switching chamber, thus ensuring current flow to the long horizontal elements of the actuating element and ultimately to the moving contact of the device. The current flow, and therefore the moving points, can also be insulated as bearing elements, thereby preventing the moving contact points of the actuating element of the vacuum switching chamber from welding together. The latter requires bridging flexible conductors.This arrangement can enable a safe and reproducible switching process.

[0020] Within the characteristics of the switch arrangement, the actuating elements of the vacuum switching chamber are mechanically coupled to the vacuum switching chamber. For the uniformity of the auxiliary switch's switching, it has proven particularly advantageous that the actuating elements of the vacuum switching chamber are mechanically mounted to it. An example of such an arrangement is shown in the figures. This arrangement results in high mechanical stability with only very minor deviations in the switching travel. This can be beneficial for the longevity of the switch arrangement.

[0021] For switching applications with high voltages and very low currents (e.g., cable discharges), the outer insulation of the vacuum switching chamber is additionally protected by a spark gap. The switching arrangement also includes a protective spark gap connected in parallel to the vacuum switching chamber. The protective spark gap can, for example, activate at 30 kV. However, this is a function of the selected specifications of the vacuum switching chamber. It has also proven particularly advantageous to connect a protective spark gap in parallel to the vacuum switching chamber. In this configuration, one flashover electrode is expediently mounted at one end of the rotating shaft of the vacuum switching chamber, and the second flashover electrode is conductively mounted opposite it on the mating contact. An advantageous design for the flashover electrodes is round or spherical.The end of the rotating shaft of the vacuum switching chamber can be freely chosen for the attachment of the first flashover electrode, whereby sufficient distance to the vacuum switching chamber on one side or to the actuating element on the other side must be ensured.

[0022] In a further preferred embodiment of the switch arrangement, the vacuum switching chamber can additionally have a shielding cover, and the vacuum switching chamber, the actuating elements, and the shielding cover can each be connected to the mating contact of the main switch via a high-resistance resistor when the switch is not in operation. This embodiment can make the entire switch arrangement safer and also improve the suitability of the circuit for outdoor use under weather conditions. When the switch is off, the aforementioned components are thus connected to the mating contact via a high-resistance resistor, which has no influence on the switching operations. This arrangement prevents corona discharges when the auxiliary contact system is switched off. The shielding cover can, for example, shield the vacuum switching chamber from the external environment.In a further embodiment, the resistor can additionally have a protective spark gap. This can be advantageous in cases of low current at nominal voltage.

[0023] In a preferred embodiment of the switch arrangement, the shielding cover can be made of aluminum and have at least a partially rounded surface. This shape of the shielding cover has proven particularly suitable for the switch arrangement according to the invention, both for electrical and mechanical reasons. The shielding cover has the shape of a circular segment, at least in some areas of its surface. Preferably, the shielding cover can have a surface that corresponds, at least in some sections, to a complete quarter circle.

[0024] Within a preferred aspect of the switch arrangement, the shielding cover can be mechanically attached to the mating contact via a non-conductive support. This can be the same support used to mount the actuators (radial bearing). Since there is no current flow requirement on this support, or rather, this is explicitly avoided, the mounting surface can be designed to be independent of its diameter. This results in a small radius on the mounting surface, similar to a classic clamp. This allows the use of pressure points or pressure points with a larger radius, even on a round mating contact. This arrangement has proven particularly suitable based on the mechanical and electrical requirements.

[0025] In a further advantageous embodiment of the mounting of the support for receiving the actuating elements (radial bearing), it can simultaneously serve as the mounting for the vacuum switching chamber. In this case, the support can be made of metallic, conductive material and mounted with sufficient spacing between the actuating elements, so that any flashover occurring can be dissipated via an existing protective spark gap. A particular advantage can be achieved by designing the clamp in such a way that it has flashover electrodes, for example, in the form of spherical projections. The flashover electrodes can be positioned opposite the clamp on the long horizontal actuating element, so that the protective spark gap is formed by means of these round horizontal actuating elements.

[0026] In a further preferred embodiment of the switch arrangement, the actuating element of the vacuum switching chamber can additionally include a stainless steel spring element. It has proven particularly advantageous that the electrical switch of the vacuum switching chamber is always forced into an open switching position by a spring element without counterforce, i.e., without actuation by one or more contact arms. This can increase the reliability of the auxiliary circuit. Furthermore, in this embodiment, it has proven particularly advantageous that the spring element is made of a weather-resistant material such as stainless steel. This design enables a particularly smooth switching travel and can also compensate for high mechanical loads.

[0027] In a preferred embodiment of the switch arrangement, the contact arm of the main switch can comprise a section of silver-plated copper, at least at the contact point with the actuating elements of the vacuum switching chamber. This type of contact has proven to be particularly durable for the main switch in the inventive embodiment of the main and auxiliary switches. The arrangement is suitable for a wide voltage and current range and requires very little maintenance.

[0028] Regarding further advantages and technical features of the switch arrangement, reference is made to the description of the switch arrangement, the figures and the description of the figures, and vice versa.

[0029] Further details, features, and advantages of the subject matter of the invention will become apparent from the dependent claims and from the following description of the figures and the associated examples. The figures show: Fig. 1 a schematic overview of the switch arrangement according to the invention; Fig. 2 a schematic overview of the switch arrangement according to the invention; Fig. 3 a schematic overview of the switch arrangement according to the invention in the open state; Fig. 3 a sketch of the circuit of the switch arrangement according to the invention in the open state; Fig. 4 a schematic overview of the switch arrangement according to the invention with mechanical contact of the actuating elements; Fig. 4 a sketch of the circuit of the switch arrangement according to the invention with mechanical contact of the actuating elements; Fig. 5 a schematic overview of the switch arrangement according to the invention with the auxiliary switch closed and the main switch still open; Fig. 5 a sketch of the circuit of the switch arrangement according to the invention with the auxiliary switch closed and the main switch still open.Fig. 6A A schematic overview of the switch arrangement according to the invention in the closed state of the auxiliary and main switches; Fig. 6A A sketch of the circuit of the switch arrangement according to the invention in the closed state of the auxiliary and main switches.

[0030] In the Figure 1 A schematic representation of a switch arrangement 1 according to the invention, comprising a main switch and an auxiliary switch 2, is shown. The main switch can have the design of a single-column disconnect switch, wherein the contact arrangement can be equipped with one or two movable contact arms 3, which, due to the design of the moving contacts, are also referred to as contact strips. An embodiment with two contact arms 3 is shown in the Figure 2The diagram illustrates this. Known contacts are made of copper or stainless steel rods with round and / or rectangular cross-sections, as well as fixed contacts made of copper or stainless steel rods. A vacuum switching chamber 2, which has an actuating element 7, is used as an auxiliary switch. In this example, the vacuum switching chamber 2 is part of the fixed / counter-contact 6 of the single-column disconnect switch and is arranged on the mounting element 5 for mounting the vacuum switching chamber 2 onto the counter-contact 6. The counter-contact 6 forms the current-carrying connection to the main current path. The actuating element 7 is part of the mounting element 5 of the vacuum switching chamber 2. The actuating element 5 of the vacuum switching chamber 2 can be rigidly connected to the vacuum switching chamber 2 or, as shown in the diagram, decoupled. In the off state, all parts with a free potential can be connected to the counter-contact 6 via a high-resistance resistor.The high-resistance component has no influence on the switching operations but prevents corona discharges when the vacuum switching chamber 2 is switched off. A spring element (not shown, 13) in the vacuum switching chamber 2 and / or a spring element 13 between the actuating elements 7 forces the auxiliary contact system into the "off" state without any force being applied to the actuating elements 7. The auxiliary contact system 2 is switched on by the force of the movable main contact system 3 and switched off by the spring elements 13 of the auxiliary contact system when the force of the movable contact arm(s) 3 ceases due to movement away from the mating contact 6. The contact arm 3 can be formed from the actual movable element 3 and a contact strip 4 through which the current flows. The vacuum switching chamber 2 can also have an actuating guide 8 in the form of a stainless steel fork at the actuating point of the vacuum switching chamber 2.This actuating guide 8 can contribute to particularly good mechanical guidance of the contact arrangement 1. The actuating elements 7 can be designed as copper and / or stainless steel rods. The following advantages result from the use of the arrangement according to the invention: Leads in during the closing process of the disconnect switch, thus protecting the main contact (switching commutation currents, vacuum switching chamber 2 closes). Follows in during the opening process of the disconnect switch, thus protecting the main contact (switching commutation currents, vacuum switching chamber 2 opens). Lead-in and follow-out are adjustable via copper and / or stainless steel rods, the actuating element 7, and the vacuum switching chambers 2 (type and characteristics). Reduced contact erosion due to faster arc extinguishing and increased switchable commutation currents and voltages. High smoothness of movement.

[0031] The Figure 2Figure 1 shows an embodiment of the switching arrangement 1 according to the invention. Two contact arms 3 of the main switch and the vacuum switching chamber 2 as an auxiliary switch are shown. The vacuum switching chamber 2 is mechanically switched via the contact arms 3 of the main switch by the actuating elements 7.

[0032] The Figure 3AFigure 1 shows a possible switch arrangement 1 according to the invention with a special view of the vacuum switching chamber 2 as an auxiliary switch. The contact arms 3 of the main switch, which is a single-column disconnect switch, are shown. The switch is shown in the open position, and thus the contact arms 3 do not contact the mating contact 6 of the vacuum switching chamber 2. The actuating elements 7 of the vacuum switching chamber 2 are also not touched by the contact arms 3, and thus the switch of the vacuum switching chamber 2 is open. The switch of the vacuum switching chamber 2 is connected to the actuating element 7 via the fixed 15 and the movable 14 contact points. When the current path of the switching device 1 closes, the movable contact arms 3 first approach the actuating element 7 of the vacuum switching chamber 2 as an auxiliary contact. The actuating elements 3 can be made of copper and / or stainless steel rods.The switch of vacuum switching chamber 2 is still open at this time and a flashover or arc between the main and auxiliary contacts cannot occur.

[0033] The Figure 3B The corresponding circuit diagram of the one shown in the Figure 3A The illustrated configuration. The circuit diagram shows that the main switch 11 and the auxiliary switch 12 are both open. The electrical switch 12 of the vacuum switching chamber 2 can, for example, be held in the "open" position by a mechanical spring element 13. Only when the actuating elements 7 are mechanically actuated by the contact arms 3 of the main switch 11 is the switch 12 moved into a closed position (not shown here).

[0034] The Figure 4AFigure 1 shows a possible switch arrangement 1 according to the invention with a special view of the vacuum switching chamber 2 as an auxiliary switch. The movable contact arms 3 move further in the "ON" direction and contact the actuating elements 7 of the vacuum switching chamber 2. The switch of the vacuum switching chamber 2 is connected to the actuating element 7 via the fixed 15 and the movable 14 contact points. The movable arms 3 are now electrically and mechanically connected to the actuating elements 7 of the vacuum switching chamber 2 as an auxiliary contact system. The movable main contact system still has sufficient distance to the mating contact of the main contact system so that no electrical arcing can occur (e.g., due to a commutation voltage).

[0035] The Figure 4B The corresponding circuit diagram of the one shown in the Figure 4AThe constellation shown. A spring element 13 located in the vacuum switching chamber is now tensioned by the further movement of the contact arms 3 and moves the switch 13 of the vacuum switching chamber 2 into the "closed" state. The contacts of the main switch 11 are still further apart in the "off" position.

[0036] The Figure 5A Figure 1 shows a possible switch arrangement 1 according to the invention with a special view of the vacuum switching chamber 2 as an auxiliary switch. In the further movement of the current path, the vacuum switching chamber 2 is switched to the "On" state by the mechanical force exerted by the movable contact system, the contact arms 3, on the actuating elements 7. Applied voltages (e.g., commutation voltage) can now flow through the closed vacuum switching chamber 2 even before the main contacts 3 are closed via the main current path.

[0037] The Figure 5BThe corresponding circuit diagram of the one shown in the Figure 5A The illustrated configuration. The circuit diagram shows that the main switch 11 is still open and the auxiliary switch 12 is already closed. The spring element 13 is now tensioned.

[0038] The Figure 6AFigure 1 shows a possible switch arrangement 1 according to the invention with a special view of the vacuum switching chamber 2 as an auxiliary switch. Both the main contact 11 and the auxiliary contact 12 are closed. The commutation current is routed through the auxiliary contacts, and the main contacts remain protected so that they can engage without voltage and without the main contact system being damaged by arcing. The movement sequence in "ON" ends at the stop of the fixed contact 3 of the main contact system, and the spring element of the auxiliary contact is fully tensioned. The vacuum switching chamber 2 is closed and, in normal operation, is shunt-circuited and is therefore, among other things, short-circuit proof.

[0039] The Figure 6B The corresponding circuit diagram of the one shown in the Figure 6BThe illustrated configuration. The circuit diagram shows that the main switch 11 and the auxiliary switch 12 are both closed. The spring element 13 is tensioned.

[0040] The following process takes place during the shutdown: 1. During the switch-off process, the main contacts 3 move towards "Off". 2. When the main contacts 3 begin to separate, the vacuum switching chamber 2 is still closed and carries the commutation current. The main contacts 3 are protected and can run out of voltage without the main contact system being damaged by arcing. The auxiliary contact system 2 now begins to open due to the force stored in the integrated spring element 13, and the actuating elements 7 follow the movement of the movable main contact system 3. This maintains the electrical and mechanical connection between the main contact system 3 and the auxiliary contact system 7. The spring element 13 generates the necessary contact pressure to press the actuating elements 7 against the main contacts 3 of the movable main contact system, or the necessary force to open the vacuum switching chamber 2 in the next step. 3.Subsequently, the auxiliary contact system 2 is further opened by the spring element 13 contained within it, parallel to the movement of the movable main contact system 3. The vacuum switching chamber 2 switches to "OFF" and immediately extinguishes the arc of the contact break, so that hardly any contact erosion occurs. The distance of the main contact system 3 is so large that flashover / back-ignition is no longer possible. In a passive system, the arc would burn until the movable contacts 7 of the auxiliary contact system 2 have moved far enough apart for the arc to extinguish. 4. The movable main contact system 3 can now leave the actuating elements 7 of the auxiliary contact system 2 without any tension. The electrical and mechanical connection between the movable main contact system 3 and the auxiliary contact system 7 is severed. Reference symbol list

[0041] 1 Switch assembly 2 Auxiliary switch 3 Contact arm 4 Contact strip 5 Mounting elements 6 Counter contact 7 Actuating element 8 Actuating guide 9 Mounting element 10 Shielding cap 11 Main switch 12 Auxiliary switch 13 Spring element 14 Movable contact point 15 Fixed contact point

Claims

1. A switch assembly (1) for an air-insulated high voltage disconnector, comprising at least one main switch and one auxiliary switch, wherein the main switch comprises a single-column disconnector with at least one movable contact arm (3) and a fixed mating contact piece (6); and the auxiliary switch comprises a vacuum switching chamber (2) with an electrical switch and at least one actuating element (7) arranged on the switch, wherein the vacuum switching chamber (2) is arranged in an electrically conductive manner on the mating contact piece (6) of the main switch; and wherein the electrical switch of the vacuum switching chamber (2) is configured to establish or interrupt, by the movable contact arm (3) of the main switch via the actuating element (7), an electrically conductive connection between the mating contact (6) of the main switch and the movable contact arm (3) of the main switch, wherein the actuating element(s) (7) of the vacuum switching chamber (2) are arranged mechanically coupled to the vacuum switching chamber (2), that the electrical switch of the vacuum switching chamber (2) closes before closing of the main switch and opens after opening of the main switch, characterised in that the switch assembly (1) additionally has a protective spark gap connected in parallel to the vacuum switching chamber (2) and a first spark-over electrode of the protective spark gap is conductively mounted at one end of the rotary shaft of the vacuum switching chamber (2) and a second transition electrode of the protective spark gap is conductively mounted opposite to the mating contact (6).

2. The switch assembly according to claim 1, wherein the main switch comprises two movable contact arms (3) and the auxiliary switch comprises two actuating elements (7).

3. The switch assembly according to any of the preceding claims, wherein the vacuum switching chamber (2) is arranged on the mating contact piece (6) of the main switch via a connecting piece made of steel (5) or aluminium.

4. The switch assembly according to any of the preceding claims, wherein the actuating element (7) of the vacuum switching chamber (2) has an electrically insulated contact point, at least in sections.

5. The switch assembly according to any of the preceding claims, wherein the vacuum switching chamber (2) additionally has a shielding cap (10) and, in the non-connected state, the vacuum switching chamber (2), the actuating elements (7) and the shielding cap (10) are each connected to the mating contact piece (6) of the main switch via a high-resistance resistor.

6. The switch assembly according to claim 5, wherein the shielding cap (10) is mechanically attached to the mating contact (6) via a non-conductive carrier.

7. The switch assembly according to any one of the preceding claims, wherein the actuating element (7) of the vacuum switching chamber (2) additionally comprises a spring element (13) made from stainless steel.

8. The switch assembly according to any one of the preceding claims, wherein the contact arm (3) of the main switch comprises an area (4) of silver-plated copper at least at the contact point to the actuating elements (7) of the vacuum switching chamber (2).