Electronic switch

Abstract

The invention relates to an electronic switch (1) for disconnecting a current flow between a first and a second bipolar grid connection (10, 12), comprising: - a semiconductor switch (3), having two semiconductors (30A, 30B), wherein the semiconductor switch (3) is adapted to switch a current of different polarity, and wherein the semiconductor switch (3) is arranged between two corresponding first connections (101, 121) of the first and the second bipolar grid connection (10, 12); and - a first and a second fuse element (5A, 5B) and a short-circuiting switch (7), which is adapted to switch a short-circuiting current via at least one of the fuse elements (5A, 5B), to trigger the at least on fuse element (5A, 5b), and to disconnect the current flow between the first and the second bipolar grid connection (10, 12), wherein the short-circuiting switch (7) is arranged between two corresponding second connections (103, 123) of the first and the second bipolar grid connection (10, 12) and between the two semiconductors (30A, 30B). The invention also relates to an electrical grid and to a method for operating an electronic current sensor.

Description

[0001] Electronic switch

[0002] The invention relates to an electronic switch for isolating a current flow between a first and a second two-pole mains connection according to the preamble of claim 1, an electrical network according to claim 11, and a method for operating an electronic switch according to claim 12.

[0003] Such an electronic switch comprises a semiconductor switch having two semiconductors, wherein the semiconductor switch is adapted to switch a current of different polarity, and wherein the semiconductor switch is arranged between two corresponding first terminals of the first and second two-pole mains connection. Furthermore, such an electronic switch comprises a first and a second fuse element and a short-circuit switch adapted to switch a short-circuit current through at least one of the fuse elements, for triggering the at least one fuse element, and for interrupting the current flow between the first and second two-pole mains connection.

[0004] The use of such electronic switches is becoming increasingly important in direct current (DC) networks. Unlike alternating current, direct current (DC) does not have a zero crossing, so there is a high risk of arcing if the circuit is improperly disconnected. In particular, disconnecting current paths carrying high direct currents using mechanical switches is slow, and the arcs caused by disconnection require significant design effort to extinguish. Furthermore, mechanical switches require a lot of space and are expensive. Semiconductor switches, which essentially provide the switching function through semiconductors such as transistors, do not cause arcs and enable high-speed switching. They also require less space and are more cost-effective to manufacture than mechanical switches.

[0005] However, with semiconductor switches, if high currents or short-circuit currents occur, there is also the risk of overload, which can damage the electronic switch or prevent it from switching the current. To counteract the risk of overload, conventional electronic switches often have fuse elements. By triggering these fuse elements, both switching failure and damage during the shutdown process can be prevented, as the current is switched off by the fuse elements. After resetting or replacing the fuse elements, the electronic switch is operational again. Furthermore, the fuse element can also protect the connected loads and cables from overload.

[0006] An electronic switch known from US Pat. No. 11,437,987 B2 utilizes a series connection of fuse elements and short-circuit switches. This design allows a short-circuit current to be switched, which triggers the fuse element and thus protects the semiconductor switch and one or more loads connected to the electronic switch from overload.

[0007] EP 3 327 886 A1 also describes an electronic switch with a fuse element that can be triggered in the event of a short circuit.

[0008] However, the electronic switches known from the state of the art are usually designed for only one direction of energy flow. The few known electronic switches with arbitrary energy flow direction require detection of the polarity of the short-circuit current and have numerous components and a large footprint.

[0009] The object of the present invention is to provide an electronic switch which is designed for any energy flow direction, has a compact construction volume and is cost-effective to manufacture.

[0010] This object is achieved by an article having the features of claim 1.

[0011] Accordingly, the short-circuit switch is arranged between two corresponding second terminals of the first and second two-pole mains connection and between the two semiconductors.

[0012] The electronic switch has a first and a second two-pole mains connection. For example, the first connections of the first and second two-pole mains connections can be designed as positive poles, with one positive pole being arranged at the switch input and the other positive pole being arranged at the switch output. Likewise, the second connections of the first and second two-pole mains connections can be designed as negative poles, with one negative pole being arranged at the switch input and the other negative pole being arranged at the switch output. The semiconductor switch has at least two semiconductors, in particular two power semiconductors designed as transistors, such as two insulated-gate bipolar transistor (IGBT) power semiconductors.Furthermore, the semiconductor switch is adapted to switch a current of different polarity, wherein the semiconductor switch is arranged between two corresponding first terminals of the first and second two-pole mains connection. For example, if the electronic switch is used as a DC switch, the semiconductor switch can be arranged in a positive or negative line between the respective first positive or negative pole of the electronic switch. In one embodiment, the electronic switch can comprise an evaluation and control unit that can control the two semiconductors of the semiconductor switch accordingly.

[0013] The fuse elements can be arranged in a current path through which a short-circuit current flows in the event of a short circuit in the first or second two-pole network, to interrupt the current flow between the first and second two-pole mains connections. Thus, the fuse elements can be arranged in series between two corresponding second connections of the first and second two-pole mains connections. Alternatively, the first and second fuse elements can each be arranged between the corresponding first connections of the first and second two-pole mains connections. In a further alternative, one fuse element can be arranged between the corresponding first connections, and the other of the two fuse elements can be arranged between the corresponding second connections.

[0014] The two fuse elements can be designed independently of each other and, when triggered, interrupt the electrical current flow between the second terminals of the power supply. Both fuse elements can be designed, for example, as fusible links or as resettable fuse elements. The fuse elements can be designed to trigger at a defined current value. The defined current value can correspond to the current value that flows through the semiconductor switch in the event of a short circuit.

[0015] The short-circuit switch is adapted to switch a short-circuit current through at least one of the fuse elements. A short-circuit switch can be understood as a switching element, such as another transistor or a thyristor, which is closed in the event of a detected short circuit in order to switch the short-circuit current through at least one of the fuse elements in order to trigger it. For example, the current in the positive or negative line can be measured using at least one current sensor and compared with the defined current value or a threshold value corresponding to the short-circuit current. Upon detection of a short circuit, the short-circuit switch can be controlled accordingly to trigger at least one fuse element.As an alternative to a current measured by a current sensor, a temperature of the semiconductor switch, in particular a junction temperature of at least one of the semiconductors, which is determined, for example, by a temperature sensor, can also be indicative of the presence of a short circuit. Based on the detection of a short-circuit temperature of the semiconductor switch, the short-circuit switch can be controlled. The control can be implemented, for example, by means of an evaluation unit or evaluation circuit that is connected to the short-circuit switch and the current or temperature sensor.

[0016] According to the invention, the short-circuit switch is arranged between the first and second fuse elements and between the two semiconductors. Such an arrangement can be understood herein as meaning that the short-circuit switch is arranged with a first terminal between the first and second fuse elements and with a second terminal between the two semiconductors in order to establish an electrical connection between the first and second fuse elements and between the two semiconductors upon detection of a short circuit, i.e., when the short-circuit current flows through the semiconductor switch.

[0017] Because only one short-circuit switch is used to switch one current direction, current polarity detection is no longer necessary. Furthermore, the electronic switch, which is implemented with only one short-circuit switch, allows for cost savings and a smaller construction volume for the electronic switch.

[0018] The electronic switch described here can also successfully complete a short-circuit test in accordance with IEC 60947-4-2 for AC switching elements.

[0019] In one embodiment, the electronic switch has a current sensor arranged between the corresponding first or second terminals. For example, if the electronic switch is configured as a DC switch, the current sensor can measure the current in the positive or negative line.

[0020] In one embodiment, the electronic switch has an evaluation and control unit which is adapted to compare a received current value from the current sensor with a threshold value and to detect the short-circuit current when the threshold value is exceeded.

[0021] The evaluation and control unit can be connected to the semiconductor switch, the short-circuit switch, and the current sensor. Furthermore, the evaluation and control unit can be implemented as an electronic circuit and / or as an integrated circuit. The threshold can be a dynamic threshold that is adjustable depending on the source or load conditions. Such a dynamic threshold can also achieve a temporal change, or a delay, between the occurrence of the short-circuit event and the actual reaction by switching the short-circuit switch. Furthermore, a dynamic threshold can be used to achieve variable adjustment with regard to the rate of rise of the short-circuit current.

[0022] In one embodiment, the evaluation and control unit is adapted to actuate the short-circuit switch when the short-circuit current is detected.

[0023] In one embodiment, the electronic switch is designed as a direct current switch. Alternatively, the electronic switch can also be designed as an alternating current switch.

[0024] In one embodiment, the corresponding first terminals are designed as connection points of a negative line, and the corresponding second terminals are designed as connection points of a positive line.

[0025] In one embodiment, the two semiconductors of the semiconductor switches each have a transistor. For this purpose, the two semiconductors can each be configured as power semiconductors, such as insulated-gate bipolar transistors (IGBTs).

[0026] In one embodiment, the semiconductor switch comprises two diodes, each arranged in antiparallel to a respective semiconductor. In one embodiment, the electronic switch comprises a thyristor. A thyristor can withstand high overloads for short periods and thus also switch high short-circuit currents.

[0027] In one embodiment, the electronic switch comprises a bypass switch, in particular a switching contact of a bypass relay, wherein the bypass switch is arranged parallel to the semiconductor switch between the two corresponding first terminals. Upon actuation of the bypass switch, the current path can be bridged by the semiconductor switch.

[0028] By using a bypass relay, power loss in the electronic switch can be saved, allowing a larger proportion of energy to be made available to the load.

[0029] In one embodiment, the first and the second fuse element are each arranged between the corresponding first terminals and / or the corresponding second terminals of the first and second two-pole mains connection.

[0030] For example, the two fuse elements can be arranged in series between two corresponding second terminals of the first and second two-pole mains connections. Alternatively, the first and second fuse elements can each be arranged between the corresponding first terminals of the first and second two-pole mains connections. In a further alternative, one fuse element can be arranged between the corresponding first terminals, and the other of the two fuse elements can be arranged between corresponding second terminals.

[0031] The invention also relates to an electrical network comprising: at least one electronic switch as described herein.

[0032] Furthermore, the invention relates to a method for operating an electronic switch, in particular an electronic switch as described herein, comprising:

[0033] Detecting, with a current sensor, a short-circuit current between corresponding first terminals or second terminals of a first and second two-pole mains connection of the electronic switch, wherein a semiconductor switch comprising two semiconductors is adapted to switch a current of different polarity and is arranged between the two corresponding first terminals; and short-circuiting, based on the detection of the short-circuit current, with a short-circuit switch a path between the corresponding second terminals of the first and second two-pole mains connection and the two semiconductors, to trigger the first or second fuse element and to interrupt the current flow between the first and second two-pole mains connection.

[0034] The concept underlying the invention will be explained in more detail below with reference to the exemplary embodiments illustrated in the figures. They show:

[0035] Fig. 1 is a view of an electronic switch with a bypass switch in a closed position;

[0036] Fig. 2 is a view of an electronic switch with the bypass switch in an open position;

[0037] Fig. 3 is a view of an electronic switch with the bypass switch in an open position and with the first and second terminals reversed;

[0038] Fig. 4 is a view of an electronic switch with the bypass switch in an open position with the fuse elements arranged between the second terminals; and

[0039] Fig. 5 Method steps of a method for operating an electronic switch.

[0040] Figure 1 shows a view of an electronic switch 1 with a bypass switch 34 in a closed position.

[0041] In the embodiment shown in Figure 1, the electronic switch 1 is designed to interrupt a current flow between a first two-pole mains connection 10 and a second two-pole mains connection 12. In the embodiment shown, the respective first connections 101, 121 of the first and second two-pole mains connections 10, 12 are designed as negative poles, with one negative pole being arranged at the input of the electronic switch 1 and the other negative pole being arranged at the output of the electronic switch 1. Likewise, the respective second connections 121, 123 of the first and second two-pole mains connections 10, 12 can be designed as positive poles, with one positive pole being arranged at the input of the electronic switch 1 and the other positive pole at the output of the electronic switch 1. In the embodiment shown, the direction of energy flow can be selected as desired.Thus, the first two-pin power connector 10 can be used as an input, and the second two-pin power connector 12 can be used as an output. Alternatively, the first two-pin power connector 10 can be used as an output, and the second two-pin power connector 12 can be used as an input.

[0042] A positive or negative line runs between the respective corresponding terminals 101, 121, 103, 123 in the electronic switch 1. Furthermore, positive or negative lines for electrically connecting the electronic switch 1 to a first network 200 and a second network 400 can be arranged accordingly at the corresponding terminals 101, 121, 103, 123. The first network 200 and the second network 400 are shown by way of example as dashed connecting lines arranged at the corresponding terminals 101, 121, 103, 123. For example, an energy storage device can be arranged on each of the dashed connecting lines, or an energy storage device connected to the AC voltage grid via an inverter, or a feed-in from a renewable source connected to a battery storage device via the switch.

[0043] Furthermore, Figure 1 shows a semiconductor switch 3 comprising two semiconductors 30A, 30B, which is adapted to switch a current of different polarity. As shown in Figure 1, the semiconductor switch 3 is connected between two corresponding first terminals 101, 121 of the first and second two-pole mains terminals 10, 12.

[0044] In the embodiment shown in Figure 1, the two semiconductors 30A, 30B are depicted as insulated-gate bipolar transistors (IGBTs). The two semiconductors 30A, 30B are configured to create a bidirectional switch. As shown in Figure 1, a first semiconductor 30A is embodied as an n-channel transistor, and a second semiconductor 30B is embodied as a p-channel transistor. The two semiconductors 30A, 30B have a common emitter terminal.

[0045] Furthermore, in the embodiment shown, a diode 32A, 32B is arranged antiparallel to each of the semiconductors 30A, 30B. A bypass switch 34, which in the embodiment shown is designed as a switching contact of a bypass relay, is also arranged parallel to the semiconductor switch 3 between the two corresponding first terminals 101, 121. Upon actuation of the bypass switch 34, the current path through the semiconductor switch 3, or through the semiconductors 30A, 30B, is bridged, as shown in Figure 1.

[0046] The first and second fuse elements 5A, 5B shown in Figure 1 are arranged in series between two corresponding second terminals 103, 123 of the first and second two-pole mains connection 10, 12. The two fuse elements 5A, 5B are designed independently of one another and, when triggered, interrupt the flow of electrical current between the two second terminals 103, 123. In the embodiment shown, the two fuse elements 5A, 5B are designed as fusible links. In an alternative embodiment, the two fuse elements 5A, 5B are designed as resettable fuse elements. The fuse elements 5A, 5B are designed to trigger at a defined current value that corresponds to a current value that flows through the semiconductor switch 3 in the event of a short circuit.

[0047] The short-circuit switch 7 in the electronic switch 1 shown in Figure 1 is adapted to switch a short-circuit current through at least one of the fuse elements 5A, 5B. In the embodiment shown, the short-circuit switch 7 is implemented by a thyristor, which is activated in the event of a detected short circuit to switch the short-circuit current through at least one of the fuse elements 5A, 5B in order to trigger this fuse element 5A, 5B.

[0048] In the embodiment shown, the current in the negative line is measured by the current sensor 9 shown and compared with the defined current value or a threshold value corresponding to the short-circuit current. Upon detection of a short circuit, an evaluation and control unit 40 connected to the current sensor 9 and the short-circuit switch 7 can control the short-circuit switch 7 accordingly to trigger the at least one fuse element 5A, 5B. In a further embodiment, a short circuit can also be detected and the short-circuit switch 7 controlled by detecting the junction temperature of at least one of the semiconductors 30A, 30B. The short-circuit switch 7 is arranged between the first and second fuse elements 5A, 5B and between the two semiconductors 30A, 30B.As shown in Figure 1, the short-circuit switch 7 is connected to a first terminal of both fuse elements 5A, 5B, so that one fuse element 5A is arranged between the short-circuit switch 7 and terminal 103 of the positive line, and another fuse element 5B is arranged between the short-circuit switch 7 and terminal 123 of the positive line. Thus, depending on the wiring of the terminals, the short-circuit switch 7 can switch a short-circuit current across one of the two fuse elements 5A, 5B to trigger one of the two fuse elements 5A, 5B.

[0049] Furthermore, in the embodiment shown in Figure 1, the second terminal of the short-circuit switch 7 is connected to the common emitter terminal of the first and second semiconductors 30A, 30B, so that a semiconductor 30A is arranged between the short-circuit switch 7 and the terminal 101 of the negative line and a further semiconductor 30B is arranged between the short-circuit switch 7 and the terminal 121 of the negative line.

[0050] If a switch-on process (without a short-circuit event) is to occur with the semiconductor switch 3 shown in Figure 1, the first semiconductor 30A or the second semiconductor 30B is switched on first, depending on the energy flow direction. For example, if the energy flow direction is from the first network 200 to the second network 400, the second semiconductor 30B is switched on. If the energy flow direction is unknown, both semiconductors 30A, 30B can be switched on. Without a short-circuit event, the first semiconductor 30A and the second semiconductor 30B can be switched on and off as desired. This can be done, for example, by the evaluation and control unit 40.

[0051] By closing the bypass switch 34, the electronic switch 1 is transferred to an energy-saving mode, as shown in Figure 1. In energy-saving mode, switching off the semiconductors 30A, 30B has no effect because the short-circuit current flows via the bypass switch 34. For switching off without the short-circuit switch 7, the bypass switch 34 would have to be opened. However, such switching processes are generally too slow to safely switch off short-circuit currents, or the mechanical contacts can fail and be destroyed due to arcing in the event of a short circuit. In the embodiment shown in Figure 1 with the short-circuit switch 7, the short-circuit current is switched off very quickly by the fuse element 5A or 5B.A prior determination of the polarity of the short-circuit current can be omitted since short-circuit currents from the first network 200 into the second network 400, as well as short-circuit currents from the second network 400 into the first network 200, both flow through the short-circuit switch 7.

[0052] For example, in the event of a short circuit in the first network 200, the short-circuit current is first detected by the current sensor 9, and based on the detection of the short-circuit current, the short-circuit switch 7 is switched on. The short-circuit current is then distributed between the first semiconductor 30A or the diode 32A and the bypass switch 34, and in parallel between the semiconductor 30B or the diode 32B. As a result, the second fuse element 5B is triggered.

[0053] Due to the parallel connection of the bypass switch 34, when the bypass switch 34 is switched on, the current load on the semiconductors 30A, 30B, or on the diodes 32A, 32B, is halved.

[0054] In the event of a short circuit in the second network 400, the first fuse element 5A is triggered in a manner analogous to that described above.

[0055] Figure 2 shows a view of an electronic switch 1 with a bypass switch 34 in an open position. Thus, the electronic switch 1 shown in Figure 2 corresponds to the electronic switch 1 already shown in Figure 1, with the only difference being that the bypass switch 34 is shown in an open position.

[0056] For example, in the event of a short circuit in the first network 200, with the bridging switch 34 open, there are several ways to switch off the resulting short-circuit current:

[0057] First, based on the detection of the short-circuit current, the

[0058] Short circuit current through the first semiconductor 30A can be switched off.

[0059] Alternatively, based on the detection of the short-circuit current, the

[0060] The short-circuit switch 7 is opened, causing the second fuse element 5B to trip. Preferably, based on the detection of the short-circuit current, the short-circuit switch 7 is opened and the first semiconductor 30A is deactivated. This provides redundancy, which allows for shutdown by another component if a single component fails. This also ensures that a fuse element 5A, 5B is always triggered in the event of a short circuit. This allows for reliable traceability of short-circuit events.

[0061] Figure 3 shows a view of an electronic switch 1 with a bypass switch 34 in an open position. The embodiment of the electronic switch 1 shown in Figure 3 corresponds to the electronic switch 1 already shown in Figure 2, with the only difference being that the arrangement is shown horizontally mirrored compared to the arrangement shown in Figure 2, i.e., the first terminals 101, 121 are arranged at the top in Figure 3, and the second terminals 103, 123 are arranged at the bottom.

[0062] Figure 4 shows a view of an electronic switch 1 with the bypass switch 34 in an open position and with the fuse elements 5A, 5B arranged between the first terminals 101, 121. The embodiment of the electronic switch 1 shown in Figure 4 corresponds to the electronic switch 1 already shown in Figure 2, with the only difference that the fuse elements 5A, 5B are each arranged between one of the semiconductors 30A, 30B and one of the first terminals 101, 121. In the embodiment shown, the current sensor 9 is arranged between the second terminals 103, 123.

[0063] Figure 5 shows method steps of a method 1000 for operating an electronic switch.

[0064] The method 1000 comprises the following steps:

[0065] Detecting 1010 with a current sensor a short-circuit current between corresponding first terminals or second terminals of a first and second two-pole mains connection of the electronic switch, wherein a semiconductor switch comprising two semiconductors is adapted to switch a current of different polarity and is arranged between the two corresponding first terminals; and

[0066] Short-circuiting 1020, based on detecting the short-circuit current, with a short-circuit switch a path between the corresponding second terminals of the first and second two-pole mains terminals and the two semiconductors, to trigger the first or second fuse element, and to disconnect the current flow between the first and second two-pole mains terminals.

[0067] List of reference symbols

[0068] 1 Electronic switch

[0069] 10, 12 Two-pin mains connection

[0070] 101 , 121 First connection

[0071] 103, 123 Second connection

[0072] 3 semiconductor switches

[0073] 30A, 30B semiconductors

[0074] 32A, 32B diode

[0075] 34 bridging switch

[0076] 5A, 5B fuse element

[0077] 7 short-circuit switch

[0078] 9 Current sensor

[0079] 40 Evaluation and control unit

[0080] 200, 400 First and Second Network

[0081] 1000 procedures

[0082] 1010 Detect

[0083] 1020 Short circuit

Claims

Patent claims 1. An electronic switch (1) for isolating a current flow between a first and a second two-pole mains connection (10, 12), comprising: a semiconductor switch (3) comprising two semiconductors (30A, 30B), wherein the semiconductor switch (3) is adapted to switch a current of different polarity, and wherein the semiconductor switch (3) is arranged between two corresponding first terminals (101, 121) of the first and second two-pole mains connection (10, 12);and a first and a second fuse element (5A, 5B) and a short-circuit switch (7) adapted to switch a short-circuit current through at least one of the fuse elements (5A, 5B), for triggering the at least one fuse element (5A, 5B), and for interrupting the current flow between the first and second two-pole mains connection (10, 12), characterized in that the short-circuit switch (7) is arranged between two corresponding second connections (103, 123) of the first and second two-pole mains connection (10, 12) and between the two semiconductors (30A, 30B); 2. Electronic switch (1) according to claim 1, characterized by a current sensor (9) arranged between the corresponding first or second terminals (101, 103, 121, 123).

3. Electronic switch (1) according to claim 2, characterized by an evaluation and control unit (40) adapted to compare a received current value from the current sensor (9) with a threshold value and to detect the short-circuit current when the threshold value is exceeded.

4. Electronic switch (1) according to claim 3, characterized in that the evaluation and control unit (40) is adapted to actuate the short-circuit switch (7) upon detection of the short-circuit current.

5. Electronic switch (1) according to one of the preceding claims, characterized in that the electronic switch (1) is a direct current switch.

6. Electronic switch (1) according to one of the preceding claims, characterized in that the corresponding first terminals (101, 121) are designed as Connection points of a negative line are formed, and the corresponding second connections (103, 123) are formed as connection points of a positive line.

7. Electronic switch (1) according to one of the preceding claims, characterized in that the two semiconductors (30A, 30B) each have a transistor.

8. Electronic switch (1) according to one of the preceding claims, characterized in that the semiconductor switch (3) has two diodes (32A, 32B), and wherein in each case one diode (32A, 32B) is arranged antiparallel to one of the semiconductors (30A, 30B).

9. Electronic switch (1) according to one of the preceding claims, characterized in that the short-circuit switch (7) comprises a thyristor.

10. Electronic switch (1) according to one of the preceding claims, characterized by a bypass switch (34), in particular a switching contact of a bypass relay, wherein the bypass switch (34) is arranged parallel to the semiconductor switch (3) between the two corresponding first terminals (101, 121).

11. Electronic switch (1) according to one of the preceding claims, characterized in that the first and the second fuse element (5A, 5B) are each arranged between the corresponding first terminals (101, 121) and / or the corresponding second terminals (103, 123) of the first and second two-pole mains connection (10, 12).

12. Electrical network, comprising: at least one electronic switch (1) according to one of the preceding claims 1 to 11.

13. Method (1000) for operating an electronic switch (1), in particular according to one of the preceding claims 1 to 11, comprising: Detecting (1010) with a current sensor (9) a short-circuit current between corresponding first terminals (101, 121) or second terminals (103, 123) of a first and second two-pole mains connection (10, 12) of the electronic switch (1), wherein a semiconductor switch (3) comprising two Semiconductor (30A, 30B) adapted to switch a current of different polarity and arranged between the two corresponding first terminals (101, 121); and Short-circuiting (1020), based on the detection of the short-circuit current, with a short-circuit switch (7) a path between the corresponding second terminals (103, 123) of the first and second two-pole mains terminals (10, 12) and the two semiconductors (30A, 30B), to trigger the first or second fuse element (5A, 5B), and to disconnect the current flow between the first and second two-pole mains terminals (10, 12).

Images