POWER SWITCH

Description

[0001] The invention relates to a circuit breaker for the interruptible connection of at least two line sections, comprising at least one pair of vacuum tubes, each comprising a stationary switching contact and a movable switching contact, wherein the switching contacts of the at least one pair of vacuum tubes are electrically connected in series.

[0002] The use of vacuum tubes as power switching elements, as known, for example, from WO 2014 / 075739 A1 and US 2013 / 270089 A1, enables the realization of climate-neutral switching devices, particularly when combined with housings filled with dehumidified air as an insulating medium, since insulating gases such as sulfur hexafluoride can be dispensed with. The vacuum tubes are generally installed horizontally or vertically in the housings with the moving contact at the bottom. The use of vacuum tubes as switching elements for high-voltage and extra-high-voltage applications may require a series connection of several vacuum tubes to ensure the dielectric strength of the circuit breaker. The use of vacuum tubes in circuit breakers offers the advantage over other switch types, such as gas circuit breakers, that the vacuum tubes are essentially maintenance-free to operate.The use of vacuum tubes in circuit breakers is already known in the state of the art.

[0003] DE 10 2015 212 826 A1 describes a feedthrough for the electrically conductive connection of two conductor sections through a housing wall. The feedthrough comprises a vacuum tube in which the conductor sections are electrically insulated from the encapsulation of the vacuum tube and, by the encapsulation, also from the housing. The two conductor sections can be electrically separated by switching the vacuum tube.

[0004] DE 10 2016 218 355 A1 discloses a cable sleeve assembly for electrical power supply, in which an interrupter unit switchable by means of a drive unit is arranged within a cable sleeve between two electrical line sections of an electrical line of one phase of an electrical cable. The interrupter unit can be designed as a vacuum tube with a stationary and a movable contact.

[0005] The invention is based on the object of providing an improved circuit breaker with at least two switchable vacuum tubes.

[0006] To achieve this object, the invention provides that the movable switching contacts of the vacuum tubes are coupled to a common actuator and can be switched simultaneously by a movement of the actuator.

[0007] The advantage of the inventive solution is that it eliminates the need for switching the movable switching contacts of the vacuum tubes by several separate drive units, which require complex synchronization for simultaneous switching of at least two vacuum tubes. The coupling of the movable switching contacts of the vacuum tubes to the actuator can be achieved, for example, by means of a relatively simple movement mechanism, thus advantageously reducing the space required for the circuit breaker and its design complexity.

[0008] The switching contacts of the pair of vacuum tubes are connected in series when the switching contacts are closed, and the two line sections are electrically connected. When the switching contacts of the vacuum tubes are opened, the movable switching contacts are spaced apart from the stationary switching contacts, so that the two line sections are no longer electrically connected. The simultaneous switching of both vacuum tubes makes it possible to switch voltages with the circuit breaker that are higher than the rated voltage of a single vacuum tube. This makes it possible, for example, to use the circuit breaker based on vacuum tubes for switchgear and switchgear with rated voltages U m > 245 kV. Even at lower rated voltages, for example at rated voltages U m ≤ 170 kV, the use of two vacuum tubes can result in savings compared to the use of a single, larger tube.In addition, it is also possible to increase the short-circuit breaking capacity of the circuit breaker by using two vacuum tubes.

[0009] The stationary switching contacts of the vacuum tubes are preferably each electrically connected to one of the line sections to be interruptibly connected. The movable switching contacts switch the vacuum tube and thus the connection between the line sections when it is moved by a movement of the actuator itself and the physical contact between the stationary switching contact and the movable switching contact of a vacuum tube is interrupted. The movable switching contacts of both vacuum tubes of a pair of vacuum tubes are electrically connected to one another to form the series circuit. This can be achieved, for example, by the movable switching contacts each being connected to a conductor of the circuit breaker via a sliding contact, wherein the switching contacts are electrically connected to one another via the conductor at least when the vacuum tubes are closed.In this way, when the vacuum tubes are closed, a current flow is achieved between the two line sections that are separably connected by the circuit breaker.

[0010] The stationary switching contact and the movable switching contact of the vacuum tubes are at least partially housed in an evacuated capsule, with a contact surface between the stationary switching contact and the movable switching contact being located within the evacuated capsule when the vacuum tube is closed, i.e., within the vacuum within the capsule. Due to the arrangement of the contact surface in the vacuum, it is possible to switch high voltages with the vacuum tube, and in particular with a series connection of two vacuum tubes. The circuit breaker can be designed, for example, for switching voltages of 245 kV and higher, but also for lower voltages, for example, in a range from 10 kV to 170 kV or in a range from 170 kV to 245 kV.

[0011] According to the invention, the movable switching contacts can be coupled to the actuator via a common actuating element. By using a common actuating element, simultaneous switching of the movable switching contacts of the vacuum tubes can be achieved in a simple manner. By moving the actuator, the actuating element can be moved in such a way that, due to the coupling between the movable switching contacts and the actuating element, the movable switching contacts also move in such a way that they are moved from a closed position to an open position.It is of course possible that a further movement of the actuator, for example a movement in a reverse direction of movement, also enables a movement of the movable switching contacts from an open state to a closed state, so that both an opening of the switching contacts of the vacuum tubes and thus of the circuit breaker and a closing of the switching contacts of the vacuum tubes or the circuit breaker by the actuator is possible.

[0012] According to the invention, the actuating element can be a rotating shaft, in particular a crankshaft, or a linearly movable actuating element. Designing the actuating element as a shaft, in particular a crankshaft, or as a linearly movable actuating element makes it possible to switch the vacuum tubes or move the movable switching contacts using a mechanism that is as simple to implement as possible. Furthermore, the use of a rotating shaft, such as a crankshaft, or a linearly movable actuating element can achieve simultaneous and, in particular, rapid movement of the movable switching contacts.

[0013] To couple the movable switching contacts to the actuating element, the invention provides for the movable switching contacts of the vacuum tubes to be coupled to the actuating element via a connecting rod. Each of the connecting rods can be mounted, for example, via a pivot bearing on the associated movable switching contact and via another pivot bearing on the actuating element. In this way, in particular, a rotary movement of an actuating element designed as a shaft or a linear movement of an actuating element designed as a linear actuating element can be converted into a movement of the movable switching contacts for switching the vacuum tubes.

[0014] According to the invention, the actuator and / or the connecting rods can be made of an electrically insulating material, in particular a glass-fiber-reinforced plastic and / or a Kevlar-reinforced plastic. The use of insulating materials for the actuator and / or the connecting rods prevents the electrical voltage applied to the movable switching contacts in the closed state from also being applied to the components of the movement mechanism and / or the actuator.

[0015] In a preferred embodiment of the invention, it can be provided that the vacuum tubes of the at least one pair of vacuum tubes are arranged at an angle to one another such that the movable switching contacts are directed towards the actuating element and are coupled to it, wherein the actuating element is arranged between the vacuum tubes. The vacuum tubes can be arranged in a V-arrangement, similar to the cylinders in a V-type internal combustion engine. The movable switching contacts can be directed downwards and coupled to an actuating element arranged, in particular, centrally between the vacuum tubes. The vacuum tubes can be arranged in the same position with respect to a longitudinal direction of the actuating element, or it can be provided that the vacuum tubes are slightly offset from one another in the longitudinal direction of the actuating element in order to simplify the coupling of the movable switching contacts to the actuating element.

[0016] Furthermore, it can be provided according to the invention that the circuit breaker comprises three pairs of vacuum tubes, wherein the switching contacts of the vacuum tubes of each pair are each electrically connected in series to two line sections and the pairs are each spaced from one another in a longitudinal direction of the actuating element, wherein the actuating element is coupled to the movable switching contacts of the vacuum tubes of the three pairs. In this way, it is also possible to carry out simultaneous switching of three separate phases in a three-phase system using the circuit breaker. Each pair of vacuum tubes is assigned to two line sections of one phase, so that a total of three different phases can be switched via the three pairs of vacuum tubes. The actuating element is coupled to the movable switching contacts of all vacuum tubes, so that the three phases orThe six vacuum tubes can be switched simultaneously by a single movement of the actuator. The spaced-apart arrangement of the pairs along the longitudinal direction of the actuator allows for a space-saving circuit breaker design that can be switched using a simple and robust mechanism.

[0017] According to the invention, the actuator can be an electric motor. The electric motor can, for example, achieve a rotary movement of the actuating element, in particular an actuating element designed as a shaft or a crankshaft. It is also possible for a rotary movement of the electric motor to be converted into a linear movement of an actuating element designed as a linear actuating element, or for the electric motor to be a linear motor, which can directly generate a linear movement of a linear actuating element.

[0018] In a preferred embodiment of the invention, it can be provided that the vacuum tubes are arranged in a common housing, in particular in a dead-tank circuit breaker housing or a life-tank circuit breaker housing. In a dead-tank circuit breaker housing, the housing is at a ground potential. In a life-tank circuit breaker housing, the housing is insulated from the outside. The circuit breaker housing can be filled with an insulating protective gas, e.g., dehumidified air, also referred to as clean air, or another protective gas, e.g., sulfur hexafluoride. The housing protects the vacuum tubes from external influences and also serves to shield the switching contacts of the vacuum tubes, which carry high voltage, particularly when closed, from their surroundings.Furthermore, the actuator and / or a movement mechanism provided for coupling the movable switching contacts to the actuator can also be accommodated in the housing. It is also possible for the actuator to be located outside the housing, and for example, a movement mechanism for implementing the coupling between the movable switching contacts and the actuator is partially guided through the housing.

[0019] The vacuum tubes are each arranged in a bushing through which one of the line sections is routed into the housing. This advantageously allows for space-saving integration of the vacuum tubes into the housing. Particularly in a housing connected to ground potential, the vacuum tubes can also be used to insulate the bushings, thus simplifying the overall design of the circuit breaker and saving space.

[0020] According to the invention, the feedthroughs are arranged at an angle to one another in a housing ceiling, with the adjusting element being arranged between and below the feedthroughs. Particularly with feedthroughs arranged at an angle to one another, it is possible to also arrange the vacuum tubes at an angle to one another, so that, as described above, a V-shaped arrangement of the vacuum tubes is also possible when integrating them into the feedthroughs.

[0021] Further advantages and embodiments of the invention will become apparent from the exemplary embodiments described below and from the drawings, which schematically show: Fig. 1 shows a representation of a first embodiment of a circuit breaker according to the invention, Fig. 2 shows a representation of a vacuum tube, Fig. 3 shows a first embodiment of a movement mechanism of a circuit breaker according to the invention, Fig. 4 shows a second embodiment of a movement mechanism of a circuit breaker according to the invention, and Fig. 5 shows a second embodiment of a circuit breaker according to the invention.

[0022] In Fig. 1 A schematic representation of a first embodiment of a circuit breaker 1 according to the invention is shown. The circuit breaker 1 according to the invention comprises a housing 2, wherein in a housing cover 3 of the housing 2, two bushings 4 are arranged at an angle to each other. In each of the bushings 4, a vacuum tube 5 of a pair of vacuum tubes 5 is arranged. The vacuum tubes 5 each comprise a stationary switching contact 6 and a movable switching contact 7, wherein the stationary switching contact 6 is connected to a line section 9 via an electrical connection 8. The structure of a vacuum tube 5 is described below with reference to Fig. 2 explained in more detail.

[0023] The pair of vacuum tubes 5 serves to interruptibly connect the two line sections 9. For this purpose, the two movable switching contacts 7 are each electrically connected to a conductor 10 via a sliding contact, so that at least when the vacuum tubes 5 are closed or in the conducting state, the movable switching contacts 7 of the vacuum tubes 5 are electrically connected to one another. When the switching contacts 6, 7 are closed, i.e., when the circuit breaker 1 is closed, the line sections 9 are electrically connected to one another.

[0024] The movable switching contacts 7 are connected to an actuator 13 via a movement mechanism 11 comprising an actuating element 12. By moving the actuator 13, the movable switching contacts 7 of the vacuum tubes 5 can be switched simultaneously. Closed switching contacts 6, 7, i.e., conductive vacuum tubes 5, can be switched simultaneously from the closed to the open position by moving the movable switching contacts 7 by moving the actuator 13. Conversely, it is also possible for the movable switching contacts 7 to be moved from the open, i.e., the blocking, position to the closed position by further moving the actuator 13, particularly in a reverse direction. In this way, the connection between the line sections 9 can be interrupted or an interrupted connection can be reconnected.

[0025] The integration of the vacuum tubes 5 into the feedthroughs 4 of the housing 2 enables a space-saving arrangement of the vacuum tubes 5 within the housing 2. Furthermore, the arrangement of the vacuum tubes 5 at an angle to one another, i.e., a V-arrangement of the vacuum tubes, enables a simple implementation of simultaneous switching of the vacuum tubes 5 via the control element 12 and the actuator 13.

[0026] The housing 2 can, for example, be a dead-tank circuit breaker housing that is at ground potential. Alternatively, the housing 2 can also be a life-tank circuit breaker housing that is insulated from the outside. In the example shown here, it is a dead-tank circuit breaker housing, with the line sections 9 being insulated from the housing 2 not only by the schematically drawn ceramic insulators 14 but also by the vacuum tubes 5. The interior 15 of the housing 2 can also be filled with an insulating gas, for example, dehumidified air or sulfur hexafluoride, for insulation purposes.

[0027] In Fig. 2 A schematic sectional view of a vacuum tube 5 is shown. The vacuum tube 5 comprises an airtight capsule 16, which is made of an insulating material and whose interior 15 is evacuated. Both the stationary contact 6 and the movable contact 7 are guided into the interior 15 of the capsule 16. A bellows 17 made of an airtight material is provided to seal the vacuum in the interior 15 of the capsule 16 in the region of the movable switching contact 7. By moving the movable switching contact 7, as indicated by the arrow 18, an electrical connection between the stationary switching contact 6 and the movable switching contact 7 can be established or interrupted.When the movable switching contact 7 is moved towards the stationary switching contact 6 so that the contact sections 19 of the stationary and movable switching contacts 6, 7 come into contact, the switching contacts 6, 7 are closed and a conductive connection exists between the stationary switching contact 6 and the movable switching contact 7. Conversely, when the contact sections 19 are in contact, an electrical connection between the switching contact 6 and the movable switching contact 7 can be interrupted by moving the movable switching contact 7 away from the stationary switching contact 6. The area of ​​the contact sections 19 is partially surrounded by a shield 20 made of an electrically conductive material, which serves to form an electric field formed in the interior 15 of the capsule 16 and to limit the spread of metallic material of the switching contacts 6, 7 that has evaporated during the switching processes.

[0028] As in Fig. 1 As shown, for example, the stationary switching contact 6 of a first vacuum tube 5 can be connected via the electrical connection 8 to a line section 9 and the movable switching contact 7 can be connected via the conductor 10 to the movable switching contact 7 of a second vacuum tube 5, wherein the stationary switching contact 6 of the second vacuum tube 5 is also connected to a line section 9 to be connected. In this way, a series connection of the vacuum tubes 5 is realized, which makes it possible to realize a switchable connection between two line sections 9 whose voltage level lies above the rated voltage of an individual one of the vacuum tubes 5.

[0029] In Fig. 3 A first embodiment of a movement mechanism 11 for switching the vacuum tubes 5 is shown. The actuating element 12 is designed as a crankshaft, which is coupled via a connecting rod 21 to the movable contacts 7 of the vacuum tubes 5 arranged in a V arrangement. The connecting rods 21 are each fastened to the movable switching contacts 7 and to the crankshaft via a pivot bearing 22. The actuating element 12 can be rotated in the direction of arrow 23 by the actuator 13, which is designed, for example, as an electric motor. The rotary movement of the actuating element 12 spaced the movable switching contacts 7 from the stationary switching contacts 6, and the switching contacts 6, 7 are thus opened.Conversely, when rotating in the opposite direction to the direction of arrow 23, the stationary switching contacts 7 can move toward the stationary switching contacts 6, so that the switching contacts 6, 7 are closed and the vacuum tubes 5 can thus be switched to be electrically conductive.

[0030] In Fig. 4 A second exemplary embodiment of the movement mechanism 11 of a circuit breaker 1 according to the invention is shown. In this exemplary embodiment, the actuating element 12 is designed as a linearly movable actuating element, to which the movable switching contacts 7 of the vacuum tubes 5 are coupled, as described above, via a connecting rod 21 and two pivot bearings 22. The linearly movable actuating element 12 is mounted in a guide 24 and is connected to the Fig. 4 coupled to an actuator 13 (not shown), for example, an electric linear motor. The actuator 13 can move the linearly movable actuating element 12 in the guide in the direction of arrow 25 in order to open the switching contacts 6, 7 by moving the movable switching contacts 7. Closing the switching contacts 6, 7 can correspondingly occur by moving the linearly movable actuating element 12 against the direction of arrow 25, so that the movable switching contacts 7 are moved back into contact with the stationary switching contacts 6.

[0031] In Fig. 5 A second embodiment of a circuit breaker 1 according to the invention is shown. The circuit breaker 1 comprises three pairs 26 each consisting of two vacuum tubes 5, which are arranged offset along a longitudinal direction of the actuating element 12. Each of the pairs 26 of vacuum tubes 5 serves for the switchable connection of two line sections 9. Due to the use of three pairs 26 of vacuum tubes 5, the circuit breaker 1 enables electrical connections to be switched in a three-phase power system, with each pair 26 of vacuum tubes 5 switching one phase. The movable switching contacts 7 are coupled to the actuating element 12 via the connecting rods 21 and the pivot bearings 22. The movement mechanism can be configured according to the Fig. 3 oder 4 shown embodiments. By a movement of the actuator 13, a simultaneous movement of all movable switching contacts 7 of the pairs 26 of vacuum tubes 5 can take place, so that all three phases can be switched simultaneously by the circuit breaker 1. Of course, the movable switching contacts 7 of a pair 26 of vacuum tubes 5, for example, each via a conductor 10 as described above, can be connected to Fig. 1 was shown, conductively connected, so that the two line sections 9, which are electrically connected to the vacuum tubes 5 of a pair 26, are electrically conductively connected or electrically separated depending on the switching state of the vacuum tubes 5.

[0032] Of course, even when designing a circuit breaker with three pairs 26 of vacuum tubes 5, the vacuum tubes 5 can each be arranged in a V-arrangement, as described above. Additionally or alternatively, it is possible for the vacuum tubes 5 to each be arranged in a bushing 4 in the housing cover 3 of a housing 2 of the circuit breaker 1, so that an overall compact design is achieved for the circuit breaker 1 for switching three-phase current. In this exemplary embodiment, the actuator 13 is located outside the housing 2, with the actuating element 12 being passed through an outer wall of the housing 2 and connected to the actuator 13. Of course, it is also possible for the actuator 13 to be arranged inside the housing 2.

[0033] To isolate the actuator 13 from the high voltage, it can be provided in all embodiments that the actuating element 12, or the crankshaft or the linearly movable actuating element, as well as the connecting rods 21, are made of an insulating material such as a glass-fiber-reinforced plastic or a Kevlar-reinforced plastic. In this way, a current flow through the movement mechanism 11 or the actuating element 12 to the actuator 13 is prevented even when the circuit breaker 1 is closed. List of reference symbols

[0034] 1Circuit breaker 2Housing 3Housing cover 4Feedthrough 5Vacuum tube 6Fixed switching contact 7Movable switching contact 8Electrical connection 9Cable section 10Conductor 11Movement mechanism 12Control element 13Actuator 14Ceramic insulator 15Inner 16Capsule 17Bellows 18Arrow 19Contact surface 20Plate 21Connecting rod 22Pivot bearing 23Arrow 24Guide 25Arrow 26Pair

Claims

1. Circuit breaker for the interruptible connection of at least two sections of line (9), comprising at least one pair of vacuum tubes (5), which respectively comprise a fixed switching contact (6) and a movable switching contact (7), the switching contacts (6, 7) of the at least one pair of vacuum tubes (5) being electrically connected in series, and the movable switching contacts (7) of the vacuum tubes being coupled to a common actuator (13) and able to be simultaneously switched by a movement of the actuator (13), the vacuum tubes (5) being arranged in a common housing (2), a dead-tank circuit breaker housing or a live-tank circuit breaker housing, characterized in that the vacuum tubes (5) are respectively arranged in a feedthrough (4), through which in each case one of the sections of line (9) is fed into the housing (2), the feedthroughs (4) being arranged at an angle to one another in a housing top (3) of the housing (2), an actuating element (12) being arranged between and under the feedthroughs (4).

2. Circuit breaker according to Claim 1, characterized in that the movable switching contacts (7) are coupled to the actuator (13) by way of a common actuating element (12) .

3. Circuit breaker according to Claim 2, characterized in that the actuating element (12) is a rotating shaft, in particular a crankshaft, or a linearly movable actuating element.

4. Circuit breaker according to Claim 2 or 3, characterized in that the movable switching contacts (7) of the vacuum tubes (5) are coupled to the actuating element (12) in each case by way of a connecting rod (21).

5. Circuit breaker according to one of Claims 2 to 4, characterized in that the actuating element (12) and / or the connecting rods (21) consist of an electrically insulating material, in particular a glass-fibre-reinforced plastic and / or a Kevlar-reinforced plastic.

6. Circuit breaker according to one of Claims 2 to 5, characterized in that the vacuum tubes (5) of the at least one pair (26) of vacuum tubes (5) are arranged at an angle to one another in such a way that the movable switching contacts (7) are directed towards the actuating element (12) and are coupled to it, the actuating element (12) being arranged between the vacuum tubes (5).

7. Circuit breaker according to Claim 6, characterized in that the circuit breaker (1) comprises three pairs (26) of vacuum tubes (5), the switching contacts (6, 7) of the vacuum tubes (5) of each pair (26) being electrically connected in series with in each case two sections of line (9) and the pairs (26) being at a distance from one another in each case in a longitudinal direction of the actuating element (12), the actuating element (12) being coupled to the movable switching contacts (7) of the vacuum tubes (5) of the three pairs (12).

8. Circuit breaker according to one of the preceding claims, characterized in that the actuator (13) is an electric motor.