High-voltage electrical switchgear with damping means
Patent Information
- Authority / Receiving Office
- ES · ES
- Patent Type
- Utility models
- Current Assignee / Owner
- ORMAZABAL CORP TECHNOLOGY A I E (100 00)
- Filing Date
- 2026-02-26
- Publication Date
- 2026-08-05
Abstract
Description
High-voltage electrical switchgear with damping means OBJECT OF THE INVENTION The present invention falls within the field of electrical power distribution installations and, in particular, relates to a gas-insulated high-voltage electrical switchgear incorporating a damping mechanism designed to ensure a proper mechanical and electrical connection between electrical contacts. This damping mechanism prevents or reduces the so-called "bouncing" effect between contacts, which can occur during the phase prior to the final seating of the contacts in their connected position. BACKGROUND OF THE INVENTION Currently, high-voltage electrical switchgear used in power distribution networks is typically installed in metal enclosures, commonly called switchgear or cells. This switchgear integrates various operating devices, such as circuit breakers, disconnectors, and earthing switches, designed to perform switching, connecting, isolating, and earthing functions for the installation. Thus, in the event of a fault in the distribution line, or the need to carry out a cut-off for reasons of construction, maintenance or reconfiguration of the load distribution, it is possible to activate these switching means to guarantee the continuity of supply, prevent users from being left without voltage and ensure the protection of people and electrical equipment, such as transformers. Among the various switching devices used in high-voltage electrical switchgear, the following can be mentioned: - Disconnectors, which incorporate two contacts capable of joining to allow current to flow, or separating to establish an isolation distance in accordance with applicable regulations or manufacturer specifications, thus ensuring that current cannot flow. In certain configurations, these disconnectors may also include a third contact for grounding the electrical circuit. - Switching devices based on SF6 gas-insulated circuit breaker technology, in which contact separation occurs inside a chamber filled with this gas in order to interrupt the current, both the nominal current and the overcurrent fault current. However, SF6 has the disadvantage of being a gas with a high environmental impact due to its very high global warming potential (GWP = 22,800). Consequently, and in line with current sustainability objectives, more environmentally friendly alternatives are being developed and adopted to replace or reduce the use of this gas. Vacuum circuit breakers consist of a vacuum bottle containing a pair of electrical contacts, one fixed and one movable. The movable contact is operated by a mechanism to switch the circuit on and off. However, these vacuum circuit breakers are not commonly used for interrupting nominal current, primarily due to their high cost compared to other technologies. As a consequence of the limitations associated with the switching devices described above, several alternatives have been developed based on the incorporation of a vacuum circuit breaker in a secondary or branch circuit. This configuration ensures the interruption of the electrical current while reducing the cost of the solution, since the vacuum circuit breaker used can be of lower performance, as it only needs to conduct the current for a short period of time. In these solutions, the secondary circuit remains inactive in permanent mode, and is only traversed by the electric current when the switch-disconnector arranged in the main circuit begins its opening sequence, producing a progressive transfer of the current from the main circuit to the secondary circuit. Since the vacuum breaker generally remains at rest during stable operation of the installation, it does not need to be sized to withstand the demanding electrical and dielectric conditions of steady-state operation, such as short-circuit making capacity. There are examples of prior art that address this type of solution in which there is a main circuit, equipped with a first means of operation, for example, a switch-disconnector, through which the electric current flows in permanent mode, and a secondary circuit, provided with a second means of operation, typically a vacuum switch, through which the electric current flows in shunt during the opening operation. In these configurations, during the opening sequence of the circuit breaker, the moving contact of the breaker intercepts, along its opening stroke, a free end of the secondary circuit, thus initiating a progressive transfer of current from the primary circuit to the secondary. During this phase, current flows simultaneously through both circuits. Next, the disconnect switch separates from the main circuit without an electric arc, since the current is already being diverted to the secondary circuit. As the opening continues, the action of the disconnect switch's moving contact on the secondary circuit causes the vacuum breaker to open, interrupting the electric current, extinguishing the arc, and thus reaching the open position. Subsequently, the moving contact of the disconnect switch detaches from the free end of the secondary circuit, allowing the vacuum switch to close its contacts again, but without current flow, since the secondary circuit remains open. This achieves the disconnected position. If the switchgear incorporates an earthing contact, the moving contact of the switch-disconnector continues its opening movement until it intercepts said earthing contact, thus reaching the earthing position. In this regard, several prior art documents describing solutions of this type can be mentioned, including ES2387862T3, ES2526220T3, ES2525080T3, DE102004006476B4, WO2006074975A1 or CN1148255A. In all the prior art examples mentioned, the moving contact of the switch-disconnector intercepts a free end of the secondary circuit during its opening stroke. The instant this moving contact reaches the free end, a simultaneous mechanical and electrical contact is established between the two parts. However, the approach speed of the moving contact of the disconnect switch is high enough that, at the moment of impact, a rebound is highly likely: that is, one of the parts briefly recoils from the other after the initial collision. This phenomenon, known as contact bounce or chattering, occurs when the contacts of a switch do not establish a clean and stable connection, but instead bounce several times before finally settling. During this process, the contacts can open and close repeatedly in a very short time interval, increasing the likelihood of parasitic arcing between them. The presence of such arcs accelerates the mechanical and electrical wear of the contact surfaces, as the areas subjected to the impact and successive rebounds suffer erosion and premature deterioration, reducing the lifespan of the components and potentially requiring more frequent maintenance or replacement. Furthermore, the presence of a parasitic arc can lead to the unwanted reactivation of the electrical circuit after a power interruption, with the consequent risk of damage to devices connected to the circuit. An arc can also occur between two different phases of the circuit breaker, which carries a significant risk of severe damage to the equipment itself. Therefore, it is highly desirable to have a solution that avoids the rebound effect by cushioning the impact between the moving contact of the switch-disconnector and the free end of the secondary circuit, thus preventing the generation of parasitic electric arcs during the opening phase of the switch-disconnector. Several examples from the State of the Art can be cited where the objective of the invention is to avoid the aforementioned rebound effect. On the one hand, we can cite document EP4330999A1, in which the solution comprises a contact maintenance element configured to maintain mechanical and electrical contact between an auxiliary means arranged at the free end of the secondary circuit and the moving contact of the main switch when said auxiliary means is actuated by the moving contact of the main switch. The auxiliary means arranged at the free end of the secondary circuit comprises said contact maintenance element, the latter being configured in an elastomeric material based on EPDM, polyurethane, natural rubber, or thermoplastic and coated with an electrically conductive layer or with an electrically conductive pad. This prior art example presents certain drawbacks, primarily the problem of adding extra elements to control or prevent the "bounce effect." Besides increasing the overall cost of the solution due to the need for an additional element, this extra element is located in the auxiliary medium at the free end of the secondary circuit and must be attached or connected to the auxiliary medium in some way, such as by press-fitting, screwing, riveting, etc. This connection can be damaged or broken by the direct impact of the main switch's moving contact on the contact-maintaining element, potentially causing the latter to separate from the auxiliary medium and thus lose its function of preventing the bounce effect.Furthermore, over time and due to the impacts of the moving contact of the main switch on the contact maintenance element, the latter may suffer some deterioration which in turn leads to the loss of impact damping and ultimately the loss of its function of preventing the rebound effect. Other examples of the state of the art can also be mentioned, such as EP4372778A1 and ES1323083U, which also describe this type of solution that includes a main circuit, equipped with a switch-disconnector through which the electric current flows in permanent mode, and a secondary circuit provided with a vacuum switch, through which the current flows in shunt during the opening maneuver. In particular, in the case of ES1323083U, the invention is specifically aimed at preventing the aforementioned rebound effect. To this end, a damping system is proposed, arranged at one end of the secondary circuit, opposite the end containing the auxiliary means. This system incorporates a pivot element equipped with a return spring (and, optionally, an additional spring). The fundamental idea of this solution consists of absorbing the impact by means of the controlled tilting of a lever that is part of the secondary circuit, guaranteeing its return without the need to incorporate additional elements at the point of impact, that is, between the auxiliary means and the moving contact of the main switch, as occurs in the solution described in EP4330999A1. On the other hand, we can cite document EP2720244A1, which deals with a vacuum switch where the bounce effect between its contacts must be prevented during the switch closing operation, specifically between the moving and fixed contacts. This is achieved through elastic damping means located between the upper terminal and a heat dissipation element. The damping means can be configured in a rubber or elastomer element, in a piston-cylinder arrangement, or in a metal bellows capable of absorbing the impact between the electrical contacts. As in prior art example EP4330999A1, this case also employs an additional element to prevent contact bounce between the switch contacts, which similarly increases the final cost of the solution. Furthermore, adding another element to prevent contact bounce complicates the switch's design and operation and increases its dimensions, which can negatively impact its integration within an electrical switchgear enclosure. In known prior art configurations, such as those described in documents ES2387862T3 and EP4330999A1, the auxiliary means, which acts as an intercepting point for the moving contact of the main circuit's disconnect switch, is connected to the rest of the moving part of the secondary circuit (such as a lever) by means of a one-way joint equipped with a mechanical stop and return spring. Although this joint allows the auxiliary means to remain rigid during the opening sequence and pivot only during the closing sequence, repeated impacts occur between the moving contact of the main switch and the auxiliary means during both operations.This abrupt transfer of force generates concentrated dynamic stresses at the joint's connection point, causing accelerated mechanical wear, the appearance of play, and fatigue of the return spring, which compromises the mechanical stability and reliability of the vacuum switch operation. Although these architectures allow switching between the primary and secondary circuits, they do not solve the fundamental problem of the progressive degradation of the articulation point, nor do they eliminate the adverse effects of impact or rebound resulting from these repeated stresses. Therefore, there is a need to develop a mechanism capable of reducing or eliminating the dynamic stresses that occur at the junction point between the moving end of the secondary circuit (auxiliary medium) and the rest of the moving part of the secondary circuit during both the opening and closing sequences. In particular, it is necessary to mitigate the impacts generated by the moving contact of the disconnect switch when it intercepts the auxiliary medium, since these impacts not only cause cumulative mechanical wear and the development of clearances, but can also lead to a rebound effect, which increases the likelihood of parasitic electrical arcing, negatively impacting the reliability, durability, and operational safety of the electrical switchgear. Therefore, a solution is required that effectively dampens the shock between the moving contact of the disconnect switch and the end of the secondary circuit or auxiliary medium, both during the opening and closing sequences, while ensuring: - the mechanical stability of the assembly, - the integrity of the vacuum switch drive, - the prevention of mechanical and electrical rebounds, - and the reduction of accumulated wear in the unidirectional joint of the secondary circuit. DESCRIPTION OF THE INVENTION The present invention falls within the field of electrical power distribution installations and, in particular, relates to gas-insulated high-voltage electrical switchgear incorporating a damping device. This type of switchgear, which may consist of a load-break switch or a short-circuit current circuit breaker, is commonly used in transformer substations, distribution centers, and, in general, in any infrastructure intended for the control, protection, and operation of high-voltage electrical networks. Specifically, the invention applies to switchgear installed in gas-insulated metal enclosures or cells, inside which there is at least one operating device provided with a fixed contact and a moving contact, such as a disconnect switch or a vacuum circuit breaker, among others.These operating devices are intended to perform cutting, connecting, sectioning and / or grounding functions of the installation. The invention focuses specifically on a damping means, the purpose of which is to improve the mechanical and electrical reliability of the maneuvers within the gas-insulated switchgear. The damping device of the invention solves the aforementioned problems. It prevents the rebound effect between electrical parts or contacts during electrical and mechanical connection, establishing a clean and stable connection without rebound. This prevents the formation of parasitic electrical arcs and their associated problems, such as erosion of contact surfaces or reactivation of the electrical circuit after the electrical current has been interrupted by the switching device. The damping element of the invention forms part of a control mechanism for a first and a second operating means, such as a disconnect switch and a vacuum circuit breaker, respectively, incorporated within the enclosure. The control mechanism comprises at least one actuating lever for opening the second operating means located in a secondary circuit of the electrical switchgear. This second operating means is actuated by the lever in the opening sequence when the moving contact of the first operating means located in a main circuit of the electrical switchgear intercepts or makes mechanical and electrical contact with at least one auxiliary means located at a first end of the lever, the free end of the secondary circuit, causing the lever to move. This auxiliary means may be connected to the lever by a one-way joint provided with a mechanical stop and return spring.The lever comprises a mechanical connection point with the moving contact of the second operating means, so that displacement of the lever in turn causes displacement of the moving contact of the second operating means. The damping means allows for clean and stable mechanical and electrical contact, without bounce, between the moving contact of the first operating means and the auxiliary means of the control mechanism; that is, this damping means is configured to dampen the mechanical contact and, where applicable, the electrical contact between the moving contact of the first operating means and the auxiliary means during the opening sequence, and to dampen the mechanical contact between these parts during the closing sequence. The damping element is installed at the first end of the lever, further away from that end than the auxiliary element. In other words, the damping element is installed between the auxiliary element and the inner part of the lever, so the auxiliary element is closer to the first end. This damping element comprises an elastomeric material, independent of both the lever and the auxiliary element, such as an elastic ring. The auxiliary element is closer to the first end of the lever, which is the point of contact of the moving contact of the main circuit breaker, while the damping element is located further inside the lever, where it effectively absorbs the impact energy without being at the point of direct impact.In this way, the invention resolves the rebound effect and parasitic arcs associated with the interaction between the moving contact of the primary operating means and the auxiliary means, while also reducing wear and fatigue in the articulation of the secondary circuit through which the auxiliary means is connected to the lever. This is because the damping acts on the lever, not the impact end, which is the auxiliary means. This reduces the stresses concentrated in the one-way articulation, minimizes backlash, and extends the service life of the moving assembly. Furthermore, during the closing sequence, the damping means cushions the mechanical contact that occurs between the auxiliary means and the lever when the auxiliary means returns to its original position due to the force exerted by the return spring, once it is released by the moving contact of the primary operating means.In this way, overshooting or sharp impacts (unwanted mechanical impacts) are avoided, specifically when the auxiliary means returns quickly to the lever, and accidental reconnections of the secondary circuit are prevented, guaranteeing a stable closure free of unwanted reactivations. By relocating the damping element on the lever, in a position further away from the first end where the auxiliary element is located, the solution dissipates the shock energy away from the direct point of impact, providing stable maneuvers, clean closures and greater durability of the assembly, without the damping element suffering any deterioration that would imply the loss of impact damping and ultimately the loss of its function of preventing the rebound effect. The high-voltage electrical switchgear incorporating a damping mechanism also includes a pivoting element at a second end of the lever, which allows the lever to tilt relative to a fixed part of the control mechanism. This pivoting element integrates a return spring, enabling the lever to tilt relative to the fixed part of the control mechanism. This tilting of the lever absorbs part of the impact of the moving contact of the primary operating means on the auxiliary means of the control mechanism during the opening sequence, thus establishing a mechanical and electrical contact between the two parts without rebound.The articulation element exerts a force opposite to the displacement of the moving contact of the first operating means, and this phenomenon allows the contact, both mechanical and electrical, to be maintained between the moving contact of the first operating means and the auxiliary means of the control mechanism until the moving contact of the first operating means separates from the auxiliary means of the control mechanism (free end of the secondary circuit) and allows the second operating means to close its contacts, since said articulation element also causes the lever of the control mechanism to return to its initial or rest position once the auxiliary means is released from the moving contact of the first operating means. DESCRIPTION OF THE FIGURES Figure 1.- Shows a perspective view of the enclosure that incorporates inside the high voltage electrical switchgear with damping means. Figure 2.- Shows a front elevation view of the electrical switchgear of Figure 1 in its connection maneuvering position, where the lever of the control mechanism with the damping means and the auxiliary means, according to an embodiment of the invention, are in their initial or rest position. Figure 3.- Shows a front elevation view of the electrical switchgear of Figure 1, with the damping means according to the embodiment of Figure 2, in the opening sequence in an intermediate maneuvering position between connection and cut-off, where the moving contact of the first maneuvering means is in electrical and mechanical connection with the auxiliary means located at the second end of the lever or free end of the secondary circuit. Figure 4.- Shows a front elevation view of the electrical switchgear of Figure 1, with the damping means according to the embodiment of Figure 2, once the moving contact of the first operating means of the free end of the secondary circuit has been separated, with the lever of the control mechanism and the auxiliary means being returned to their initial or rest position. Figure 5.- Shows a front elevation view of the electrical switchgear of Figure 1, with the damping means according to the embodiment of Figure 2, in the closing sequence where the moving contact of the first operating means is in mechanical connection with the auxiliary means located at the second end of the lever or free end of the secondary circuit. PREFERRED EMBODIMENT OF THE INVENTION An example of a preferred embodiment is described below, referring to the figures cited above, without limiting or reducing the scope of protection of the present invention. The high-voltage electrical switchgear (1) provided with a damping means (10) according to the present invention can be used, for example, in electrical transformation centers, distribution centers, substations, etc., where the electrical switchgear (1), with at least one function of cutting / connecting, sectioning, grounding and which may consist of a load-break or short-circuit current switch, comprises inside an enclosure (2) a first operating means (3), such as a disconnect switch, provided with a fixed contact (5) and a movable contact (6) and installed in a main circuit of the electrical switchgear (1), as well as a second operating means (4), such as a vacuum switch, provided with a fixed contact (5) and a movable contact (6) and installed in a secondary circuit of the electrical switchgear (1), as shown in Figures 1 to 5. As shown in the embodiment example in Figures 2 to 5, the electrical switchgear (1) of the invention comprises a damping means (10) that forms part of a control mechanism (7) associated with at least one of the operating means (3, 4). This control mechanism (7), incorporated inside the enclosure (2), comprises at least one lever (8) intended for actuating the opening of the second operating means (4), said second operating means (4) being actuated by the lever (8) when the movable contact (6) of the first operating means (3) makes mechanical and electrical contact with at least one auxiliary means (9) of the control mechanism (7) and displaces said lever (8) during the opening sequence of the switchgear (1), as can be seen in Figure 3. The lever (8) comprises a mechanical connection point (14) with the movable contact (6) of the second operating means (4), such that displacement of the lever (8) causes displacement of the movable contact (6) of the second operating means (4), separating the contacts (5, 6) from each other during the opening sequence of the electrical switchgear (1). Consideration has been given to the possibility that the mechanical connection point (14) may comprise a clearance hole (19), configured to generate a delay in the opening actuation of the second operating means (4), the latter beginning its opening when said clearance has been consumed, thus introducing a controlled mechanical delay without the need for additional components.Subsequently, the moving contact (6) of the first operating means (3) is decoupled from the auxiliary means (9), allowing the second operating means (4) to close its contacts (5, 6) again, but without current flow, since the secondary circuit remains open, as shown in figure 4. In this way, the lever (8) of the control mechanism (7) and the auxiliary means (9) are returned to their initial or rest position. In the opening sequence of the switchgear (1), as shown in Figure 3, the moving contact (6) of the first operating means (3) establishes mechanical and electrical contact with the auxiliary means (9) of the control mechanism (7), so that said auxiliary means (9) pushes the lever (8) when it comes to a stop against a mechanical stop (17) arranged in the lever (8) itself. The damping means (10) is installed at a first end (11) of the lever (8), in a position further away from said first end (11) than the auxiliary means (9), i.e., the damping means (10) is installed between the auxiliary means (9) and the inner area of the lever (8), so that the auxiliary means (9) is closer to the first end (11), and said damping means (10) can also, for example, cover at least partially the outer surface of said mechanical stop (17).In this way, the impact of the auxiliary means (9) against the mechanical stop (17) is absorbed or dampened by the damping means (10), and simultaneously the impact of the moving contact (6) of the first operating means (3) against the auxiliary means (9) is absorbed, thus maintaining mechanical and electrical contact between the parts, preventing rebound, and establishing a clean and stable connection. At the same time, wear and fatigue are minimized in the one-way joint (16) of the secondary circuit, through which the auxiliary means (9) is mechanically linked to the lever (8). The damping means (10) comprises an elastomer material, independent of the lever (8) and the auxiliary means (9), and may consist of an elastic ring that covers, at least partially, the outer surface of the mechanical stop (17) of the lever (8), as shown in Figures 2 to 5. The damping means (10), in addition to being configured to dampen the mechanical and, where applicable, the electrical contact between the moving contact (6) and the auxiliary means (9) during the opening sequence of the switchgear (1), is also configured to dampen the mechanical contact between parts of the control mechanism (7) during the closing sequence of the switchgear (1). As shown in Figure 5, which represents the closing sequence of the switchgear (1), the damping means (10) dampens the mechanical contact that occurs between the auxiliary means (9) and the mechanical stop (17) of the lever (8) when said auxiliary means (9) pivots to allow the passage of the moving contact (6) and when it returns to its original position due to the force exerted by a return spring (18) arranged in the one-way joint (16), once it is released by the moving contact (6) of the first operating means (3).Furthermore, the damping element (10) prevents the auxiliary element (9) from impacting the second operating element (4) when said auxiliary element (9) pivots to allow the passage of the moving contact (6) in the closing sequence of the switchgear (1). In this way, overshooting or sharp impacts (unwanted mechanical impacts), which occur especially when the auxiliary element (9) returns rapidly towards the lever (8), particularly towards the mechanical stop (17), are avoided, and accidental reconnections of the secondary circuit are prevented, ensuring a stable closure free from unwanted reactivations. The high-voltage electrical switchgear (1) further comprises a pivot element (15) at a second end (12) of the lever (8), wherein said pivot element (15) may in turn comprise a return spring. This pivot element (15) allows the lever (8) to tilt relative to a fixed part (13) of the control mechanism (7), as shown in Figures 2 to 5. This tilting of the lever (8) absorbs part of the impact of the moving contact (6) of the first operating means (3) on the auxiliary means (9) of the control mechanism (7) during the opening sequence, thereby helping to establish a non-rebound mechanical and electrical contact between the two parts.In this case, damping occurs because the articulation element (15) exerts a force in the opposite direction to the displacement of the movable contact (6) of the first maneuvering means (3), allowing this phenomenon to maintain stable mechanical and electrical contact between the movable contact (6) of the first maneuvering means (3) and the auxiliary means (9) of the control mechanism (7), until the movable contact (6) of the first maneuvering means (3) separates from the auxiliary means (9) of the control mechanism (7), that is, the movable contact (6) of the first maneuvering means (3) separates from the free end of the secondary circuit.
Claims
1. High-voltage electrical switchgear (1) comprising an enclosure (2), said enclosure (2) including: - a first switching means (3) and a second switching means (4), configured to perform at least one function of switching, connecting, sectioning and / or earthing, said switching means (3, 4) being provided, respectively, with at least one fixed contact (5, 5') and one movable contact (6, 6'), - at least one control mechanism (7) disposed inside the enclosure (2) and configured to actuate at least one of the switching means (3, 4), said control mechanism (7) comprising at least one lever (8) intended for actuating the opening of the second switching means (4), the second switching means (4) being actuated by the lever (8) when the movable contact (6) of the first switching means (3) comes into mechanical and electrical contact with at least one auxiliary means (9) of the control mechanism (7) and displaces said lever (8),and - at least one damping means (10) provided in the control mechanism (7) for damping the mechanical and / or electrical contact between the movable contact (6) of the first operating means (3) and the auxiliary means (9), characterized in that the damping means (10) is configured to dampen the mechanical and, where applicable, the electrical contact between the movable contact (6) and the auxiliary means (9) during the opening sequence, and to dampen the mechanical contact between said parts during the closing sequence.
2. High-voltage electrical switchgear according to claim 1, characterized in that the lever (8) comprises a first end (11) and a second end (12), wherein the damping means (10) is arranged at the first end (11) of the lever (8), in a position further from said end (11) than the auxiliary means (9).
3. High-voltage electrical switchgear according to claim 1 or 2,characterized in that the damping means (10) comprises an elastomeric material, independent of the lever (8) and the auxiliary means (9).
4. High-voltage electrical switchgear according to claim 3, characterized in that the damping means (10) is an elastic ring.
5. High-voltage electrical switchgear according to claim 2, characterized in that it comprises a hinge element (15) at a second end (12) of the lever (8) that allows the lever (8) to tilt with respect to a fixed part (13) of the control mechanism (7).
6. High-voltage electrical switchgear according to claim 5, characterized in that the hinge element (15) comprises a return spring.
7. High-voltage electrical switchgear according to claim 5, characterized in that the lever (8) comprises a mechanical connection point (14) with the movable contact (6') of the second operating means (4).
8. High-voltage electrical switchgear according to claim 7,characterized in that the mechanical connection point (14) comprises a clearance hole (19) configured to generate a delay in the opening actuation of the second operating means (4).
9. High-voltage electrical switchgear according to any of the preceding claims, characterized in that the second operating means (4) is a vacuum circuit breaker.
10. High-voltage electrical switchgear according to any of the preceding claims, characterized in that the first operating means (3) is a disconnect switch.
11. High-voltage electrical switchgear (1) according to any of the preceding claims, characterized in that it is a load-break or short-circuit current circuit breaker.