PROTECTIVE SWITCH

Description

[0001] The invention relates to the technical field of a protective switching device for a low-voltage circuit with an electronic interruption unit.

[0002] Low voltage refers to voltages up to 1000 volts AC or up to 1500 volts DC. In particular, low voltage refers to voltages higher than extra-low voltage, defined as 50 volts AC or 120 volts DC.

[0003] Low-voltage circuits, networks, or installations refer to circuits with rated currents of up to 125 amperes, or more specifically, up to 63 amperes. Low-voltage circuits also include circuits with rated currents of up to 50 amperes, 40 amperes, 32 amperes, 25 amperes, 16 amperes, or 10 amperes. These current values ​​refer specifically to rated, rated, and / or tripping currents, i.e., the maximum current that normally flows through the circuit or at which the electrical circuit is typically interrupted, for example, by a protective device such as a circuit breaker, miniature circuit breaker, or miniature circuit breaker. The rated currents can be further staggered, from 0.5 A through 1 A, 2 A, 3 A, 4 A, 5 A, 6 A, 7 A, 8 A, 9 A, 10 A, etc. up to 16 A.

[0004] Miniature circuit breakers (MCBs) are long-established overcurrent protection devices used in low-voltage electrical installations. They protect conductors from damage caused by overheating due to excessive current and / or short circuits. A MCB can automatically disconnect the circuit in case of overload and / or short circuit. A MCB is a non-resetting safety device. Circuit breakers, unlike MCBs, are designed for currents greater than 125 A, and sometimes even as low as 63 A. Therefore, MCBs are simpler and more delicate in design. MCBs typically have a mounting option for installation on a DIN rail (also known as a top-mounted rail or TH35).

[0005] Miniature circuit breakers (MCBs) are electromechanical devices. They contain a mechanical switching contact or shunt trip within a housing to interrupt (trigger) the electrical current. Typically, a bimetallic element is used for tripping (interruption) in the event of a prolonged overcurrent (overcurrent protection) or thermal overload (overload protection). An electromagnetic trip with a coil is used for momentary tripping when an overcurrent limit is exceeded or in the event of a short circuit (short-circuit protection). One or more arc-quenching chambers or devices are provided. Furthermore, they include connection elements for conductors of the electrical circuit to be protected.

[0006] Protective switching devices with an electronic interruption unit are relatively new developments. These devices feature a semiconductor-based electronic interruption unit. This means that the electrical current flow of the low-voltage circuit is routed through semiconductor components or semiconductor switches that can interrupt the electrical current flow or be switched to conductivity. Protective switching devices with an electronic interruption unit also frequently feature a mechanical isolating contact system, particularly with isolating characteristics according to relevant standards for low-voltage circuits. The contacts of the mechanical isolating contact system are connected in series with the electronic interruption unit, meaning that the current of the low-voltage circuit to be protected is routed through both the mechanical isolating contact system and the electronic interruption unit.

[0007] The object of the present invention is to improve a protective switching device of the type mentioned above, in particular to specify a new, simple and improved architecture for such a protective switching device or to provide improved components for it.

[0008] European patent application EP 2 234 136 A1 describes a DC circuit breaker. The DC circuit breaker comprises a housing (2) provided with a power terminal (2a) that can be connected to a power source during use, and a load terminal (2b) that can be connected to a load during use. A contact unit (1) is arranged between the power terminal (2a) and the load terminal (2b). The contact unit (1) has mechanical contacts (10) and a semiconductor switch (11) connected in series with the mechanical contacts (10). The DC circuit breaker further comprises a switching mechanism unit (3) with an operating handle (30) used for manual operation and movably attached to the housing (2), a position detection unit (4) configured to detect an operating position of the operating handle (30), and a control unit (7).The switching mechanism unit (3) is configured to open and close the mechanical contacts (10) in response to manual operation of the operating handle (30). The control unit (7) is configured to turn on the semiconductor switch (11) when, based on the operating position detected by the position detection unit (4), it determines that the operating handle (30) has been moved from an open position to a closed position.

[0009] US Patent Application US 2021 / 0066013 A1 describes a semiconductor power switch (SSCB) with self-diagnostic, self-maintenance, and self-protection functions. The SSCB comprises: a power semiconductor device; an air gap isolator connected in series with the power semiconductor device; a sensor and actuator circuit that shuts off the power semiconductor device when a short circuit or an overload of unacceptably long duration is detected; and a microcontroller unit (MCU) that triggers the air gap isolator to create an air gap and galvanically isolate a connected load after the sensor and actuator circuit has shut down the power semiconductor device.The MCU is also configured to monitor the functionality of the air gap separator, power semiconductor device and other critical components of the SSCB, and to take corrective action as necessary to prevent damage or destruction of the SSCB and the connected load, and / or to protect people and the environment from hazardous electrical conditions.

[0010] US patent application US 2020 / 0366078 A1 describes an intelligent circuit breaker. The circuit breaker comprises an electromechanical switch, a current sensor, a voltage sensor, and a processor. The electromechanical switch is connected in series between a line input terminal and a load output terminal of the circuit breaker and is configured to be switched to either a closed or open state. The current sensor is configured to detect a current flowing in a path between the line input terminal and the load output terminal and generates a current measurement signal. The voltage sensor is configured to detect a voltage at any point along the path between the line input terminal and the load output terminal and generates a voltage measurement signal.The processor is configured to receive and process the current measurement signal and the voltage measurement signal to determine the operating status information of the circuit breaker and to determine the power consumption information of a load connected to the load output terminal.

[0011] This problem is solved by a protective switching device with the features of claim 1.

[0012] A protective switching device for the protection of a low-voltage electrical circuit, in particular a low-voltage alternating current circuit, is proposed, comprising: A housing with mains-side and load-side connections for the low-voltage circuit, a mechanical disconnect contact unit connected in series with an electronic interruption unit, wherein the mechanical disconnect contact unit is assigned to the load-side connections and the electronic interruption unit to the mains-side connections, the mechanical disconnect contact unit being operable by a handle so that opening at least one contact (or contacts) to prevent current flow or closing at least one contact (or contacts) is possible.(of the contacts) is switchable for current flow in the low-voltage circuit, that the electronic interruption unit is switchable by semiconductor-based switching elements into a high-resistance state of the switching elements to prevent current flow or a low-resistance state of the switching elements to allow current flow in the low-voltage circuit, a current sensor unit for determining the magnitude of the current in the low-voltage circuit, a control unit connected to the current sensor unit, the mechanical disconnect contact unit and the electronic interruption unit, wherein, if current and / or current-time limits are exceeded, a current flow in the low-voltage circuit is prevented, that the mechanical disconnect contact unit has a handle sensor (POS) for determining the position of the handle.

[0013] A protective switching device is proposed in which the electronic interruption unit is assigned to the mains-side connections, i.e., it is normally constantly supplied with energy / live, and the mechanical disconnecting contact unit is assigned to the load-side connections, i.e., it interrupts the current flow only to one load, while the protective switching device continues to be supplied with energy. According to the invention, the position or movement (a movement can be determined from different positions) of the handle of the mechanical disconnecting contact unit is determined, i.e., position information of the handle is obtained.

[0014] The position information is preferably determined only for the protective switching device, i.e., processed (in particular) only within the protective switching device. For this purpose, the handle sensor is connected to the control unit, so that the control unit has position information about the handle, in particular the desired closed or open state of the contacts as determined by the handle.

[0015] In one embodiment, the position information of the handle is not available outside the protective switching device.

[0016] This has the advantage that information about the switching position of the handle is available in a novel protective switching device, which can be used for further functions, in particular for functional testing of the protective switching device. The novel concept for a protective switching device is designed to be immediately operational and to be able to perform communication and other functions even after a load has been disconnected.

[0017] Advantageous embodiments of the invention are specified in the dependent claims and in the exemplary embodiment.

[0018] In an advantageous embodiment of the invention, the protective switching device is configured such that the position information is used to perform functional tests of the protective switching device. In particular, test functions are performed depending on the position information.

[0019] This has the particular advantage that different test functions can be performed depending on the switching state of the handle (desired open / closed contacts). Specifically, test functions of varying lengths can be performed. For example, longer test functions can be performed when the handle is configured for open contacts, i.e., when a load is not yet energized. Conversely, shorter test functions are preferable when the handle is configured for closed contacts, in order to avoid supplying the load with excessive energy and prevent malfunctions. This allows for advantageous test functions of both the protective switching device itself and connected loads, thereby increasing the safety of both the new type of protective switching device and the low-voltage circuit.

[0020] In an advantageous embodiment of the invention, the protective switching device is configured such that, for functional testing of the protective switching device, the voltage across the electronic interruption unit is determined (particularly with the first voltage sensor unit) when the contact(s) of the mechanical disconnect contact unit are open and the electronic interruption unit is switched to high resistance. If a first voltage threshold is undershot, a first fault condition is present, thus preventing the electronic interruption unit from switching to low resistance and / or preventing the closing of the at least one contact(s).

[0021] The first voltage threshold could be an RMS / average / rms value of the AC voltage. The first voltage threshold could be an instantaneous value of the voltage. The comparison can be made using RMS values ​​or instantaneous values ​​over time.

[0022] This serves to check the electronic interrupt unit with regard to its "switchability or switched-off state", i.e., the high resistance or high resistance of the semiconductor-based switching elements.

[0023] The first voltage threshold is advantageously 5-15% of the nominal voltage or applied voltage of the low-voltage circuit, for example, 10%. This applies to both RMS and instantaneous values ​​of the AC voltage, depending on the chosen comparison method. For example, the instantaneous value of the AC voltage can also be measured at specific points in time, e.g., at the time when the instantaneous value of the AC voltage is +300 V or -300 V.

[0024] This has the particular advantage that a simple check regarding the switching behavior of the electronic interruption unit is possible.

[0025] In an advantageous embodiment of the invention, the protective switching device is configured such that, for functional testing of the protective switching device, with the contact(s) of the mechanical disconnect contact unit open and the electronic interrupt unit switched to a high-resistance state, the electronic interrupt unit is switched to a low-resistance state for a first period of time. During this time, the voltage across the electronic interrupt unit is measured. If a second voltage threshold is exceeded, a second fault condition exists, thus preventing the electronic interrupt unit from further switching to a low-resistance state and / or preventing the closing of the at least one contact(s).

[0026] The initial time interval can range from a few microseconds, for example, 100 microseconds, to several seconds. It is essentially limited only by the manual activation of the mechanical isolating contact unit. For example, it can range from 100 microseconds to 2 ms, such as 100 microseconds, 200 microseconds, ... 1 ms, 2 ms. A voltage change can be detected during switching times in the range of 1 ms to 2 ms. The time interval can also be longer, for example, up to 1 second. Then it can be checked whether approximately 0 V (instantaneous or RMS voltage) is present across the electronic interruption (for a "longer time interval"). Since the contact(s) of the mechanical isolating contact unit are open, the time interval is only limited by the time it takes for the contacts to close, i.e., until the handle is moved to close the contacts or a specific position is reached. This means that even longer or longer periods are possible.Long test durations, well over a second, are possible. The position sensor can advantageously determine when the handle is moved, allowing the initial test duration to be adjusted accordingly.

[0027] The second voltage threshold should be less than 1 V. This has the particular advantage that the electronic interrupt unit can be checked with regard to its "switch-on capability" or its switched-on state.

[0028] In an advantageous embodiment of the invention, the closing of the at least one contact(s) of the mechanical disconnect contact unit is prevented when a fault condition exists. In particular, no enable signal is sent to the mechanical disconnect contact unit. This has the particular advantage that only a functioning protective switching device with a functioning electronic interrupt unit can be switched on. This increases operational reliability in the low-voltage circuit. It is thus ensured that the switching on and off of the electronic interrupt unit functions correctly.

[0029] In an advantageous embodiment of the invention, the protective switching device is configured such that, for functional testing, with the contact(s) of the mechanical disconnect contact unit closed and the electronic interrupt unit switched to a high-resistance state, the electronic interrupt unit is switched to a low-resistance state for a second period of time. During this low-resistance state, the voltage across the electronic interrupt unit is measured. If a third voltage threshold is exceeded, a third fault condition is present, which prevents the electronic interrupt unit from switching to a low-resistance state and / or initiates the opening of the contact(s).

[0030] The third voltage threshold should preferably be less than 1 V. The third voltage threshold can be between 0 volts (or greater than 0 volts) and less than (e.g., 10% less than) the instantaneous value of the currently applied AC voltage (especially when monitoring or comparing instantaneous values).

[0031] The second time interval can be short. For example, the second time interval can be less than 2 ms or 1 ms, specifically, for example, 500 µs or 100 µs long.

[0032] This has the particular advantage that it also allows for a check of the switch-on capability of the electronic interrupt unit in this operating state.

[0033] In an advantageous embodiment of the invention, the electronic interruption unit is switched to a low-resistance state when the instantaneous value of the voltage between the mains-side neutral conductor connection and the mains-side phase conductor connection falls below a fourth voltage threshold.

[0034] The fourth voltage threshold can be a value for (protective) extra-low voltage. For example, the fourth voltage threshold can be 50 V.

[0035] This has the particular advantage that the electronic interruption unit can be tested for its ability to be switched on at a voltage or at a voltage level that is safe. This ensures a high level of operational reliability while simultaneously testing the protective switching device.

[0036] In an advantageous embodiment of the invention, the protective switching device is configured such that, for functional testing, the voltage across the electronic interruption unit is determined when the contact(s) of the mechanical disconnecting contact unit are closed and the electronic interruption unit is switched to low resistance. If the fifth voltage threshold is exceeded, a fourth fault condition occurs, which initiates the electronic interruption unit switching to high resistance and / or the opening of the contact(s).

[0037] The fifth voltage threshold should be less than 1 V. Ideally, the fifth voltage threshold depends on the magnitude of the measured instantaneous value (also known as the RMS value) of the current.

[0038] As an alternative to the voltage threshold, or in addition to it, a resistance value of the electronic interruption unit can be determined from the measured voltage and current values ​​(e.g., instantaneous values ​​at a specific time; alternatively, RMS values). The determined resistance value is compared with a first resistance threshold. If the first resistance threshold is exceeded, the fourth fault condition is present, initiating a high-resistance state of the electronic interruption unit and / or the opening of the contacts.

[0039] The first resistance threshold depends on the electronic interrupt unit, in particular the semiconductor-based switching element. For example, the first resistance threshold is twice the resistance of the electronic interrupt unit in its intact, especially cold, state. For example, it can be less than 100 mΩ, and in particular less than 50 mΩ.

[0040] This has the particular advantage that the electronic interruption unit can be checked during operation and, in the event of a faulty electronic interruption unit, a current flow in the low-voltage circuit can be prevented, thus ensuring a safe condition.

[0041] In an advantageous embodiment of the invention, the protective switching device is configured such that, for functional testing, with the contact(s) of the mechanical disconnect contact unit closed and the electronic interrupt unit switched to a low-resistance state, the electronic interrupt unit (EU) is switched to a high-resistance state for a third period of time. In the high-resistance state, the voltage across the electronic interrupt unit is measured. If a sixth voltage threshold is undershot, a fifth fault condition is present, which initiates the electronic interrupt unit switching to a high-resistance state and / or the opening of at least one contact(s).

[0042] The third time interval should preferably be very short. For example, the third time interval can be less than 20 ms, 10 ms, 5 ms, 2 ms or 1 ms, more specifically less than 500 µs or 100 µs (any intermediate value is possible and disclosed).

[0043] This means that the loads or consumers are not disconnected from the grid for as long.

[0044] This means that the loads or consumers are not disconnected from the grid for as long.

[0045] The sixth voltage threshold can be dimensioned like the first voltage threshold. For example, the sixth voltage threshold can be 5-15% of the nominal voltage of the low-voltage circuit, for instance, 10%.

[0046] The sixth voltage threshold can be determined depending on the impedance or resistance of the load or the load current, especially the current that has flowed previously.

[0047] This has the particular advantage that a simple check of the switching behavior or the switchability of the electronic interruption unit is possible during operation.

[0048] Furthermore, in the case of an energy absorber or surge protector within the electronic interruption unit, its functionality can also be advantageously tested. If current has previously flowed in the low-voltage circuit, the freewheeling current through or the resulting voltage across the energy absorber can be checked after the resistance becomes high. If the electronic interruption unit is opened while current is flowing, the voltage rises (due to the inductance in the circuit) to the voltage of the surge protector. Thus, the functionality of the energy absorber can be tested. Advantageously, the high resistance of the electronic interruption unit can occur at the zero crossing of the current. This has the particular advantage that there is no interruption of the current. Furthermore, since the load is not supplied with current at this moment, the measurement has less impact on the load.Furthermore, a commutation process (reduction of current in the inductive circuit) does not occur and the electronic interruption unit (including energy absorber) can immediately block.

[0049] In an advantageous embodiment of the invention, the electronic interruption unit is switched to a high-impedance state when the instantaneous value of the voltage between the mains-side neutral conductor connection and the mains-side phase conductor connection exceeds a seventh voltage threshold, in particular when the instantaneous value of the voltage is at its maximum.

[0050] This has the particular advantage that the brief interruption of the power supply occurs at the maximum of the available energy, thus minimizing the impact. Furthermore, the electronic interruption unit is tested under maximum voltage, allowing for early detection of any malfunction.

[0051] The seventh voltage threshold can be greater than, for example, 160 V, 200 V, 240 V, or 300 V (any intermediate value is also possible). The instantaneous maximum voltage value is 325 volts (with a 230-volt network).

[0052] The above-mentioned functional tests are examples; other functional tests can also be used where the information from the position sensor is advantageously evaluated or used.

[0053] In an advantageous embodiment of the invention, a power supply unit is provided which is connected to, or can be connected to, the mains connections. The power supply unit is connected to the control unit to provide a power supply.

[0054] This has the particular advantage that the protective switching device is normally constantly supplied with energy, thus enabling continuous operation under normal circumstances.

[0055] In an advantageous embodiment of the invention, the connection between the power supply and the mains-side connections includes a fuse and / or a switch.

[0056] This has the particular advantage that the power supply or control unit can be switched off, e.g., for insulation measurements. Furthermore, the power supply or control unit can be fused to increase the protection of the protective switching device against further faults.

[0057] In an advantageous embodiment of the invention, the network-side connections comprise a network-side neutral conductor connection and a network-side phase conductor connection. The load-side connections comprise a load-side neutral conductor connection and a load-side phase conductor connection.

[0058] This has the particular advantage that a two-pole implementation is possible.

[0059] In an advantageous embodiment of the invention, the load-side neutral conductor connection and the load-side phase conductor connection are connected to the mechanical disconnect contact unit. In another advantageous embodiment of the invention, the electronic interruption unit is connected to the mains-side phase conductor connection.

[0060] This has the particular advantage of providing a mechanically two-pole interrupting and electronically one-pole interrupting protective switching device, with the electronic interruption unit advantageously located in the current path of the phase conductor or phase conductor (current) path. This reduces complexity and creates a reliably interrupting protective switching device that is technologically state-of-the-art yet has a simple architecture.

[0061] In an advantageous embodiment of the invention, the mechanical disconnect contact unit is designed such that the position of the handle can deviate from the position of the contacts, in particular via the closed or open state of the at least one contact.

[0062] This has the particular advantage that, for example, a so-called free release can be used, whereby the switching state of the contacts (open / closed) can be determined and monitored. A free release is specifically characterized by the fact that closing the contacts in response to an existing fault is not possible, or that closing the handle in response to a fault reopens the contacts (meaning the position of the handle differs from the position of the contacts). A blocked handle does not block the contacts, so the contacts can be opened by the control unit at any time.

[0063] According to the invention, the mechanical disconnect contact unit has a position sensor for determining the position of the at least one contact, indicating whether it is open or closed. This has the particular advantage that, by determining the actuation information of the handle, the monitoring functions can be adjusted or terminated accordingly, since, for example, the contacts are expected to close (or open). Furthermore, it is advantageous to determine whether the position of the handle deviates from the position of the contacts. In particular, for example, stuck contacts (non-opening contacts) can be detected, corresponding information can be obtained, and appropriate measures can be taken, such as increasing the resistance of the electronic interruption unit or / and communicating the status, for example, to another protective switching device or a higher-level monitoring or management system.

[0064] In an advantageous embodiment of the invention, the mechanical isolating contact unit is designed such that the contact(s) can be opened by the control unit, but not closed.

[0065] This has the particular advantage of achieving increased operational reliability, as the contact(s) cannot be accidentally closed by the control unit.

[0066] In an advantageous embodiment of the invention, the mechanical isolating contact unit is designed such that the contact(s) can only be closed by the handle when a release signal is present.

[0067] This has the particular advantage of increasing operational reliability in the circuit or the protective switching device, since only a functioning protective switching device allows the (manual) closing of the contact(s).

[0068] In an advantageous embodiment of the invention, the electronic interruption unit is a single-pole electronic interruption unit, which is provided in particular in the phase conductor current path.

[0069] This has the particular advantage that the single-pole design reduces the effort required and, at the same time, when arranged in the phase conductor current path, enables monitoring for overcurrents, short-circuit currents as well as for earth fault currents in the low-voltage circuit.

[0070] In an advantageous embodiment of the invention, a first voltage sensor unit is provided for determining the level of the voltage across the terminals of the electronic interruption unit (EU) of a current path.

[0071] This has the particular advantage that determining the voltage across the electronic interruption unit (ECU) makes it easier to assess its functionality, especially its switching capability. This results in increased operational reliability of the protective device, as a faulty ECU can be easily identified and, if necessary, the protective device can be interrupted.

[0072] In an advantageous embodiment of the invention, a second voltage sensor unit is provided for determining the voltage level at the mains-side connections, in particular between the mains-side neutral conductor connection and the mains-side phase conductor connection.

[0073] This has the particular advantage that the voltage of the mains-side connection can be monitored and, if necessary, the circuit can be disconnected in the event of over- or undervoltages. Thus, the architecture according to the invention supports increased operational reliability of the protective switching device and / or in the circuit.

[0074] In an advantageous embodiment of the invention, a display unit connected to the control unit is provided.

[0075] This has the particular advantage of enabling the display of status information from the protective switching device.

[0076] In an advantageous embodiment of the invention, a communication unit connected to the control unit is provided.

[0077] This has the particular advantage of enabling communication of status information to other protective switching devices or a higher-level management system.

[0078] In an advantageous embodiment of the invention, a temperature sensor unit is provided, in particular for determining the temperature of the electronic interruption unit. The temperature sensor unit can be connected to the electronic interruption unit and / or control unit.

[0079] This has the particular advantage of providing additional protection against overheating and subsequent burnout of the semiconductor-based switching elements of the electronic interruption unit. Furthermore, an increased current-carrying capacity can be achieved.

[0080] If at least one temperature limit is exceeded, the current path / phase conductor path may be interrupted.

[0081] In an advantageous embodiment of the invention, a differential current sensor connected to the control unit is provided.

[0082] This has the particular advantage that the protective switching device also has a residual current monitoring function (differential current monitoring) and thus offers an additional functionality.

[0083] In an advantageous embodiment of the invention, the current sensor unit is provided on the current path side between the mains-side phase conductor connection and the load-side phase conductor connection.

[0084] This has the particular advantage that the arrangement in the phase conductor current path enables monitoring for overcurrents, short-circuit currents as well as for earth fault currents in the low-voltage circuit.

[0085] In an advantageous embodiment of the invention, the low-voltage circuit is a three-phase AC circuit, and the protective switching device has additional line-side and load-side phase conductor connections, between each of which a series connection of an electronic interruption unit and one or more contacts of the mechanical disconnect contact unit is provided. Further units, such as current sensor units, first and / or second voltage sensor units, can be provided analogously. This has the particular advantage of providing a solution for three-phase AC circuits.

[0086] In an advantageous embodiment of the invention: when the contact(s) of the mechanical disconnect contact unit and low-resistance interruption unit are closed, and If a current is detected that exceeds a first current value, in particular if the first current value is exceeded for a first time limit, the electronic interruption unit remains high-impedance and the mechanical isolating contact unit remains closed; if a current is detected that exceeds a second current value for a second time limit, the electronic interruption unit becomes high-impedance and the mechanical isolating contact unit opens; if a current is detected that exceeds a third current value, the electronic interruption unit becomes high-impedance and the mechanical isolating contact unit opens.

[0087] This has the particular advantage that a graduated shutdown concept is provided for the protective switching device according to the invention.

[0088] In an advantageous embodiment of the invention, the control unit comprises a microcontroller.

[0089] This has the particular advantage that the functions according to the invention for increasing the safety of a protective switching device or the low-voltage electrical circuit to be protected can be implemented by a (customizable) computer program. Furthermore, changes and improvements to the function can be individually loaded onto a protective switching device.

[0090] All embodiments, both in dependent form with reference to claim 1 and with reference only to individual features or combinations of features of claims, result in an improvement of a protective switching device, in particular a new architecture and improvement of the safety of a protective switching device or of the electrical circuit, and provide a new concept for a protective switching device.

[0091] The described properties, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more easily understood in connection with the following description of the exemplary embodiments, which are explained in more detail in conjunction with the drawing.

[0092] The drawing shows: Figure 1 a first schematic representation of a protective switching device, Figure 2 a second schematic representation of a protective switching device.

[0093] Figure 1 Figure 1 shows a representation of a protective switching device SG for the protection of a low-voltage electrical circuit, in particular a low-voltage alternating current circuit, with a housing GEH, comprising: Network-side connections, which in the case of a network-side neutral conductor connection NG and a network-side phase conductor connection LG, load-side connections, which in the case of a network-side neutral conductor connection NL and a load-side phase conductor connection LL, the connections are intended for the low-voltage circuit; a power source is usually connected to the network-side connections / network side GRID, a load is usually connected to the load-side connections / load side LOAD; a (particularly two-pole) mechanical disconnect contact unit MK with a handle HH, load-side connection points APLL, APNL and network-side connection points APLG, APNG, wherein a load-side connection point APNL is provided for the neutral conductor, a load-side connection point APLL for the phase conductor, a network-side connection point APNG for the neutral conductor, and a network-side connection point APLG for the phase conductor.The load-side connection points APNL, APLL are connected to the load-side neutral and phase conductor connections NL, LL, so that, in particular with the handle HH, it is possible to switch the opening of contacts KKN, KKL to prevent current flow or the closing of the contacts for current flow in the low-voltage circuit, an electronic interruption unit EU, in particular a single-pole, (which in the case of a single-pole version is in particular arranged in the phase conductor,) with a network-side connection point EUG, which is in electrical connection with the network-side phase conductor connection LG, and a load-side connection point EUL, which is in electrical connection with the network-side connection point APLG of the mechanical disconnect contact unit MK, orThe electronic interruption unit EU is connected, wherein the electronic interruption unit EU has a high-resistance state of the switching elements to prevent current flow or a low-resistance state of the switching elements to allow current flow in the low-voltage circuit, or is switchable by means of (not shown) semiconductor-based switching elements; a current sensor unit SI, for determining the magnitude of the current in the low-voltage circuit, which is arranged in particular in the current path of the phase conductor; a control unit SE, which is connected to the current sensor unit SI, the mechanical disconnect contact unit MK and the electronic interruption unit EU, wherein, if current and / or current time limits are exceeded, a current flow prevention in the low-voltage circuit is initiated.

[0094] According to the invention, the mechanical disconnect contact unit MK is arranged on the load side, and the electronic interruption unit EU is arranged on the network side. The network side GRID, containing the power source, is normally under electrical voltage. An electrical load is typically connected to the load side LOAD.

[0095] The mechanical disconnect contact unit MK features a handle sensor for determining the position of the handle. Specifically, it provides information about whether the handle is intended to be open or closed, indicating the desired state of at least one contact or contacts KKN and KKL of the mechanical disconnect contact unit MK. This provides the control unit SE with information about the position of the handle HH, thus informing it whether a connected load should be supplied with power, as the novel protective switching device is advantageously supplied with power almost continuously.

[0096] The protective switching device can be designed such that the voltage across the electronic interruption unit can be advantageously determined. That is, the magnitude of a first voltage between the network-side connection point EUG and the load-side connection point EUL of the electronic interruption unit EU can be determined or is determined.

[0097] In this example, according to Figure 1 A first voltage sensor unit SU1 is provided, connected to the control unit SE, which determines the level of the voltage between the grid-side connection point EUG and the load-side connection point EUL of the electronic interruption unit EU.

[0098] When measuring voltage using the first voltage sensor unit SU1, the voltage across the series circuit of electronic interrupt unit EU and current sensor SI can alternatively be determined, as shown in Figure 1The SI current sensor unit has a very low internal resistance, so that the determination of the voltage level is not affected or only negligibly affected.

[0099] Advantageously, a second voltage sensor unit SU2 can be provided, which determines the voltage level between the mains-side neutral conductor connection NG and the mains-side phase conductor connection LG.

[0100] The first voltage sensor unit can also be replaced by using two voltage measurements (one before and one after the electronic interrupt unit). The voltage across the electronic interrupt unit is then determined by calculating the difference between these measurements.

[0101] A second voltage sensor unit, SU2, connected to the control unit SE, can be provided to determine the magnitude of a second voltage between the mains-side neutral conductor terminal NG and the mains-side phase conductor terminal LG. Furthermore, a third voltage sensor unit, SU3 (not shown), connected to the control unit, can be provided to determine the magnitude of a third voltage between the mains-side neutral conductor terminal NG and the load-side connection point EUL of the electronic interruption unit EU. The protective switching device is designed such that the magnitude of a first voltage between the mains-side connection point EUG and the load-side connection point EUL of the electronic interruption unit EU is determined from the difference between the second and third voltages.

[0102] A measuring impedance ZM can be connected between the mains-side connection points APLG and APNG of the mechanical isolating contact unit MK. The measuring impedance ZM can be, for example, an electrical resistor and / or capacitor. The measuring impedance can also be an inductor. In particular, the measuring impedance can be a series or parallel connection of a resistor and / or capacitor and / or inductor.

[0103] In the example according to Figure 1 The electronic interruption unit EU is designed as a single-pole unit, in this example in the phase conductor. Here, the mains-side connection point APNG for the neutral conductor of the mechanical disconnect contact unit MK is connected to the mains-side neutral conductor connection NG of the housing GEH.

[0104] The protective switching device SG is advantageously designed such that the contacts of the mechanical isolating contact unit MK can be opened but not closed by the control unit SE, which is indicated by an arrow from the control unit SE to the mechanical isolating contact unit MK.

[0105] The mechanical disconnect contact unit MK can be operated by an operator or user via the mechanical handle HH on the protective switching device SG to manually open or close the contacts KKL and KKN. The mechanical handle HH can indicate the switching state (open or closed) of the contacts of the mechanical disconnect contact unit MK on the protective switching device. However, the position of the handle can also differ from the switching state of the contacts, for example, if a so-called free trip is used or the contacts are stuck. In this case, for example, the mechanical disconnect contact unit MK can advantageously have a position sensor to determine the position of the closed or open state of at least one contact. This allows a discrepancy between the position of the handle HH and the switching state of the contacts to be detected. Measures for this case can be implemented.For example, stuck contacts that pose a problem for the protection of the low-voltage circuit can be detected. As a result, the electronic interruption unit can become highly impedance, a message can be displayed on the protective switching device, or a message can be sent, for example, to another protective switching device and / or a monitoring or management system.

[0106] The mechanical disconnect contact unit MK is advantageously designed such that (manual) closing of the contacts by the (mechanical) handle is only possible after an enable signal. This is also indicated by the arrow from the control unit SE to the mechanical disconnect contact unit MK. That is, the contacts KKL and KKN of the mechanical disconnect contact unit MK can only be closed by the handle HH when the enable signal (from the control unit) is present. Without the enable signal, the handle HH can be actuated, but the contacts cannot be closed ("continuous slip").

[0107] The protective switching device SG has a power supply, for example a switched-mode power supply. In particular, the power supply is intended for the control unit SE, which is indicated by a connection between the power supply and the control unit SE. Figure 1 As indicated, the power supply / power unit NT is (on the other hand) connected to the mains-side neutral conductor connection NG and the mains-side phase conductor connection LG. A fuse SS, in particular a cartridge fuse, or a switch SCH can advantageously be installed in the connection to the mains-side neutral conductor connection NG (and / or phase conductor connection LG). Figure 2 ) are planned.

[0108] According to the invention, the power supply unit NT is normally continuously supplied with energy. It is optionally protected by the fuse SS or can be switched off by the switch SCH.

[0109] Alternatively, the measuring impedance ZM can be connected to the mains-side neutral conductor connection NG via the fuse SS. This allows for the advantageous use of a three-pole electronic unit EE ( Figure 2 ) can be implemented, for example, as a module with three connection points: one neutral conductor connection point and two phase conductor connection points. The electronic unit EE, for example, includes the electronic interruption unit EU, the control unit SE, the power supply NT (including fuse SS), the current sensor unit SI, and optionally the first voltage sensor unit SU1 and / or the second voltage sensor unit SU2.

[0110] The low-voltage circuit can be a three-phase AC circuit with a neutral conductor and three phase conductors. The protective switching device can be designed as a three-phase variant and, for example, have additional line-side and load-side phase conductor connections. Electronic interruption units and (further) contacts of the mechanical disconnect contact unit, as well as current sensor units, are provided analogously between these additional line-side and load-side phase conductor connections. Furthermore, voltage measurements (e.g., by means of first voltage sensor units) can be provided.

[0111] High resistance refers to a state in which only a negligible current flows. Specifically, high resistance values ​​greater than 1 kilohm, preferably greater than 10 kilohms, 100 kilohms, 1 megahms, 10 megahms, 100 megahms, 1 gigahms, or higher.

[0112] Low resistance refers to a state in which the current value specified on the protective switching device could flow. Specifically, low resistance means resistance values ​​less than 10 ohms, preferably less than 1 ohm, 100 milliohms, 10 milliohms, 1 milliohm, or less.

[0113] Figure 2 shows a representation according to Figure 1 The difference is that the protective switching device has a two-part structure. It contains an electronic first part (EPART), for example on a printed circuit board.

[0114] The first part EPART can include the control unit SE, the first voltage sensor unit SU1, the second voltage sensor unit SU2, the current sensor unit SI, the electronic interrupt unit EU, and the power supply NT. Furthermore, the first part can include the fuse SS, a switch SCH, the measuring impedance ZM, a temperature sensor TEM (especially for the electronic interrupt unit EU), a communication unit COM, and a display unit AE. The first part EPART has only three connections: the mains-side phase conductor connection LG, a connection for the mains-side phase conductor connection point APLG of the mechanical isolating contact unit MK, a connection for a connection to the mains-side neutral conductor connection NG.

[0115] The communication unit COM can be, in particular, a wireless communication unit.

[0116] The protective switching device comprises a second part MPART, in particular a mechanical part. The second part MPART can include the mechanical isolating contact unit MK with a handle sensor POS according to the invention for reporting the position of the handle to the control unit SE, the handle HH, and a release unit FG. Furthermore, the second part can include the (neutral conductor) connection(s).

[0117] Furthermore, a differential current sensor ZCT, such as a summation current transformer, as is known from classic residual current circuit breakers, can be provided.

[0118] Further, unspecified units may be provided.

[0119] The division into two parts makes it advantageous to realize a compact protective switching device according to the invention.

[0120] The release unit / function FG enables the handle HH to actuate the contacts of the mechanical isolating contact unit when an enable signal is present. This means that closing the contacts KKL and KKN by the handle is only possible when the enable signal (from the control unit SE) is present. Otherwise, closing is not possible (the handle HH will remain in the open position / switching state). The contacts remain in the open position / switching state. Furthermore, the release unit FG can open the contacts (second function of the release unit FG) when an opening signal OEF (from the control unit SE) is present. The release unit / function FG then acts as a trigger unit to open the contacts of the mechanical isolating contact unit MK.

[0121] The current path via the mechanical disconnect contact unit MK connected in series and the single-pole electronic interruption unit EU forms, when arranged in the phase conductor according to Figure 1 , a phase conductor path, i.e., a path for the phase conductor through the protective switching device SG (inside the housing). The neutral conductor is only routed via the mechanical disconnecting contact unit MK; it is then a neutral conductor path, i.e., a path for the neutral conductor through the protective switching device SG (inside the housing).

[0122] A single-pole version of the protective switching device with only one mechanical contact, preferably in the phase conductor, can also be provided. The protective switching device then has, for example: (only) a load-side (phase conductor) connection LL to a network-side phase conductor connection LG and a network-side neutral conductor connection NG.

[0123] The neutral conductor connection on the load side is not provided in this case.

[0124] The position information can be advantageously used for performing functional tests of the protective switching device. In particular, various test functions can be performed depending on the position information.

[0125] The following situation is considered as an example: Nominal voltage or mains voltage (e.g. 230 V AC) is present at the mains-side connection LG, NG or mains side GRID or mains connection of the protective switching device. A consumer or energy sink or load is connected to the load side LOAD of the protective switching device.

[0126] The first step will be to examine the test in the OFF state of the electronic protection device.

[0127] This includes: The mechanical disconnect contact unit is open (contacts open) - i.e., handling in the open contact state - determination via the position sensor; the electronic interrupt unit is switched off (semiconductor-based switching elements high resistance); the control unit (including controller unit) is active.

[0128] The electrical potential between the electronic interruption unit and the mechanical disconnect contact unit is defined by the measuring impedance ZM and the impedance of the electronic interruption unit in the switched-off state (voltage divider).

[0129] The control unit can now switch on the semiconductor-based switching elements at any given time (and thus at a specific voltage division, depending on the instantaneous voltage value and half-wave of the voltage). Taking into account the polarity of the alternating current (AC) voltage, this allows the switching elements of the electronic interruption unit (EU) to be tested.

[0130] The electronic interruption unit EU (or the electronic switch) is thus switched on for, e.g., a very short time (in the millisecond range). The measurement time is limited by the open contacts. When these are closed, this test is terminated. According to the invention, the actuation of the handle to (intended) close the contacts is determined by the handle sensor POS. If the electronic interruption unit is functional, this can be determined by (simultaneous) voltage measurement (e.g., first voltage sensor unit, second voltage sensor unit) and (subsequent) evaluation. For example, in the case of a defective semiconductor-based switching element, it can be determined whether it remains permanently switched on (fault pattern: "continued") or permanently switched off (fault pattern: "burned out").

[0131] This covers two typical and frequent fault patterns. If the test is successful, the protective switching device, specifically the electronic interrupt unit or the mechanical disconnect contact unit, can be authorized to switch on.

[0132] If the check is not error-free, no authorization will be given to switch on the protective switching device, so that the output cannot be switched on and thus a dangerous condition is prevented.

[0133] The protective switching device is designed such that, with the contact(s) of the mechanical isolating contact unit MK open and the electronic interruption unit EU switched to high resistance, the voltage across the electronic interruption unit, i.e., the first voltage U1, is measured. If a first voltage threshold is undershot, a first fault condition is present, thus preventing the electronic interruption unit from switching to low resistance and / or the contact(s) from closing. For example, the control unit SE does not send an enable signal to the mechanical isolating contact unit MK.

[0134] The protective switching device is advantageously designed such that, in the event of a fault condition, the closing of the contact(s) of the mechanical isolating contact unit MK is prevented. In particular, no enable signal is sent to the mechanical isolating contact unit MK.

[0135] Another functional check can be performed by verifying that the contacts of the mechanical disconnect contact unit are closed and the electronic interruption unit has low resistance. The (desired) closed contact state achieved by the handle is then determined by the handle sensor.

[0136] The protective switching device is designed such that, with the contact(s) of the mechanical disconnect contact unit MK closed and the electronic interrupt unit EU switched to low resistance, the voltage across the electronic interrupt unit is measured. If a fifth voltage threshold is exceeded, a fourth fault condition occurs, which initiates the electronic interrupt unit switching to high resistance and / or the opening of the contact(s).

[0137] Furthermore, the protective switching device is designed such that, when the contact(s) of the mechanical isolating contact unit MK are closed and the electronic interruption unit EU is switched to a low-resistance state, the electronic interruption unit EU is switched to a high-resistance state for a third period of time, and the voltage across the electronic interruption unit is measured. If a sixth voltage threshold is undershot, a fifth fault condition occurs, which initiates the electronic interruption unit switching to a high-resistance state and / or the opening of the contact(s).

[0138] If the fifth or sixth fault condition is present, an opening signal (OEF) is sent from the control unit (SE) to the mechanical disconnect contact unit (MK) to initiate the opening of the contact(s). Furthermore, the control unit (SE) can send a high-impedance signal (not shown) to the electronic interruption unit. The opening of the mechanical contact(s) preferably occurs shortly before the current zero crossing, so that the mechanical switching contacts can more easily interrupt the current flow.

[0139] The electronic interruption unit is advantageously switched to a high-impedance state when the instantaneous value of the voltage between the mains-side neutral conductor connection and the mains-side phase conductor connection exceeds a seventh voltage threshold, particularly when the instantaneous value of the voltage is at its maximum.

[0140] Another functional check can be performed by verifying that the contact(s) of the mechanical disconnect contact unit are closed and the electronic interruption unit exhibits high resistance. The desired closed contact state, achieved by the handle, is then determined by the handle sensor.

[0141] The protective switching device is designed such that, when the mechanical isolating contact unit MK and the electronic interrupt unit EU are closed and switched to a high-impedance state, the electronic interrupt unit EU is switched to a low-impedance state for a second period of time. The voltage across the electronic interrupt unit is then measured. If a third voltage threshold is exceeded, a third fault condition occurs, which prevents the electronic interrupt unit from switching to a low-impedance state and / or initiates the opening of the contacts.

[0142] If the third fault condition is present, an opening signal (OEF) is sent from the control unit (SE) to the mechanical disconnect contact unit (MK) to initiate the opening of the contact(s). The opening of the at least one mechanical contact preferably occurs shortly before the current zero crossing, so that the mechanical switching contacts can interrupt the current flow more easily. Furthermore, the control unit (SE) can avoid or suppress a low-impedance signal for the electronic interruption unit.

[0143] Advantageously, the electronic interruption unit is switched to a low-resistance state when the instantaneous voltage value between the mains-side neutral conductor connection and the mains-side phase conductor connection falls below a fourth voltage threshold.

[0144] The switch-on point is advantageously chosen to be at low voltage values ​​(less than the fourth voltage threshold) in order to minimize the resulting measuring current through the consumer / energy sink / load. Furthermore, this ensures personal safety. The fourth voltage threshold can, for example, be (a maximum of) 50 V AC. This means that only safe (protective) low voltages are used during switch-on.

[0145] Another functional check can be performed by ensuring that the mechanical disconnect contact unit is closed and the electronic interrupt unit exhibits high resistance. By briefly energizing the electronic interrupt unit or its semiconductor-based switching elements, the functionality of the switching elements can be tested analogously, depending on the applied voltage polarity.

[0146] The desired closed contact state can be determined using the handle sensor. The respective function check is terminated when the handle is opened.

[0147] The measuring impedance ZM should have a very high value (resistance or impedance value) to keep losses low. For example, with a resistance of 1 MOhm, a value of 1 MOhm results in losses of approximately 50 mW in a 230 V low-voltage circuit.

[0148] Advantageously, the value of the measuring impedance should be chosen such that the current through the measuring impedance is less than 1 mA when the mains voltage is applied (within the nominal range), so that the losses in the measuring impedance ZM are (negligibly) small. Preferably, the (measuring) current is less than 0.1 mA. For example, the measuring impedance should be greater than 100 kΩ, 500 kΩ, 1 MΩ, 2 MΩ, 3 MΩ, 4 MΩ, 5 MΩ or more.

[0149] Although the invention has been illustrated and described in detail by the exemplary embodiment, the invention is not limited by the disclosed examples and other variations can be derived by the person skilled in the art within the scope of protection of the claims.

Claims

1. Circuit breaker device (SG) for protecting an electrical low-voltage AC circuit, having: - a housing (GEH) with network-side connections and load-side connections for the low-voltage AC circuit, - a mechanical isolating contact unit (MK) which is connected in series with an electronic interruption unit (EU), wherein the mechanical isolating contact unit is assigned to the load-side connections and the electronic interruption unit (EU) is assigned to the network-side connections, - wherein the mechanical isolating contact unit (MK) can be operated by means of a handle (HH), with the result that opening of at least one contact in order to avoid a current flow or closing of the at least one contact for a current flow in the low-voltage AC circuit can be switched, - wherein the electronic interruption unit (EU) can be switched, by means of semiconductor-based switching elements, to a high-impedance state of the switching elements in order to avoid a current flow or a low-impedance state of the switching elements for the current flow in the low-voltage AC circuit, - a current sensor unit (SI) for determining the level of the current of the low-voltage AC circuit, - a control unit (SE) which is connected to the current sensor unit (SI), the mechanical isolating contact unit (MK) and the electronic interruption unit (EU), wherein avoidance of a current flow in the low-voltage AC circuit is initiated if current limit values or / and current-time limit values are exceeded, wherein the mechanical isolating contact unit (MK) has a handle sensor (POS) for determining position information relating to the handle, the circuit breaker device (SG) characterized - in that the mechanical isolating contact unit (MK) is configured in such a manner that the position of the handle (HH) can differ from the position of the situation of the contacts, in particular by way of the closed or open state of the at least one contact, and - in that the circuit breaker device is configured in such a manner that checking functions are started after the closing of the contacts, which is captured by the handle sensor (POS), and the electronic interruption unit is switched on in the event of a fault-free test.

2. Circuit breaker device (SG) according to Patent Claim 1, characterized in that the handle sensor (POS) is connected to the control unit (SE), with the result that the control unit (SE) has position information relating to the position or movement of the handle, in particular a closed or open state of the at least one contact that is aimed for by means of the handle.

3. Circuit breaker device (SG) according to Patent Claim 1 or 2, characterized in that the circuit breaker device is configured in such a manner that the position information from the handle sensor (POS) is processed in the circuit breaker device.

4. Circuit breaker device (SG) according to one of the preceding patent claims, characterized in that the circuit breaker device is configured in such a manner that the position information is used to carry out functional checks of the circuit breaker device, in particular in that checking functions are carried out on the basis of the position information.

5. Circuit breaker device (SG) according to Patent Claim 4, characterized in that the circuit breaker device is configured in such a manner that, for the functional check of the circuit breaker device when the contact (s) of the mechanical isolating contact unit (MK) is / are open and the electronic interruption unit (EU) has been switched to high impedance, the level of the voltage across the electronic interruption unit is determined, in that there is a first fault condition if a first voltage threshold value is undershot, with the result that the electronic interruption unit is prevented from coming to have a low impedance or / and closing of the at least one contact is prevented.

6. Circuit breaker device (SG) according to Patent Claim 4 or 5, characterized in that the circuit breaker device is configured in such a manner that, for the functional check of the circuit breaker device when the contact (s) of the mechanical isolating contact unit (MK) is / are open and the electronic interruption unit (EU) has been switched to high impedance, the electronic interruption unit (EU) is switched to a low-impedance state for a first period of time and the level of the voltage across the electronic interruption unit is determined, in that there is a second fault condition if a second voltage threshold value is exceeded, with the result that the electronic interruption unit is prevented from further coming to have a low impedance or / and closing of the at least one contact is prevented.

7. Circuit breaker device (SG) according to Patent Claims 5 and 6, characterized in that closing of the at least one contact of the mechanical isolating contact unit (MK) is prevented when there is a fault condition, in particular no enable signal (enable) is emitted to the mechanical isolating contact unit (MK).

8. Circuit breaker device (SG) according to one of the preceding Patent Claims 4 to 7, characterized in that the circuit breaker device is configured in such a manner that, for the functional check of the circuit breaker device when the contact(s) of the mechanical isolating contact unit (MK) is / are closed and the electronic interruption unit (EU) has been switched to high impedance, the electronic interruption unit (EU) is switched to a low-impedance state for a second period of time and the level of the voltage across the electronic interruption unit is determined, in that, if a third voltage threshold value is exceeded, there is a third fault condition which prevents the electronic interruption unit from being switched to low impedance or / and initiates opening of the at least one contact.

9. Circuit breaker device (SG) according to Patent Claim 8, characterized in that the electronic interruption unit is switched to a low-impedance state when the instantaneous value of the voltage between the network-side neutral conductor connection and the network-side phase conductor connection undershoots a fourth voltage threshold value.

10. Circuit breaker device (SG) according to one of the preceding Patent Claims 4 to 9, characterized in that the circuit breaker device is configured in such a manner that, for the functional check of the circuit breaker device when the contact(s) of the mechanical isolating contact unit (MK) is / are closed and the electronic interruption unit (EU) has been switched to low impedance, the level of the voltage across the electronic interruption unit is determined, in that, if a fifth voltage threshold value is exceeded, there is a fourth fault condition which initiates the electronic interruption unit coming to have a high impedance or / and initiates opening of the at least one contact.

11. Circuit breaker device (SG) according to one of the preceding Patent Claims 4 to 10, characterized in that the circuit breaker device is configured in such a manner that, for the functional check of the circuit breaker device when the contact(s) of the mechanical isolating contact unit (MK) is / are closed and the electronic interruption unit (EU) has been switched to low impedance, the electronic interruption unit (EU) is switched to a high-impedance state for a third period of time and the level of the voltage across the electronic interruption unit is determined, in that, if a sixth voltage threshold value is undershot, there is a fifth fault condition which initiates the electronic interruption unit coming to have a high impedance or / and initiates opening of the at least one contact.

12. Circuit breaker device (SG) according to Patent Claim 11, characterized in that the electronic interruption unit is switched to a high-impedance state when the instantaneous value of the voltage between the network-side neutral conductor connection and the network-side phase conductor connection exceeds a seventh voltage threshold value, in particular when the instantaneous value of the voltage is at a maximum.

13. Circuit breaker device (SG) according to one of the preceding patent claims, characterized in that the mechanical isolating contact unit (MK) has a position sensor for determining position information relating to the closed or open state of the at least one contact.

14. Circuit breaker device (SG) according to one of the preceding patent claims, characterized in that the mechanical isolating contact unit (MK) is configured in such a manner that the at least one contact can be opened, but not closed, by the control unit (SE); in that the mechanical isolating contact unit (MK) is configured in such a manner that it is possible to close the at least one contact by means of the handle only when an enable signal is present.

15. Circuit breaker device (SG) according to one of the preceding patent claims, characterized in that the low-voltage AC circuit is a three-phase AC circuit and the circuit breaker device has further network-side and load-side phase conductor connections, between each of which there is provided a series circuit of an electronic interruption unit and a contact of the mechanical isolating contact unit.

16. Circuit breaker device (SG) according to one of the preceding patent claims, characterized in that, when the contact(s) of the mechanical isolating contact unit is / are closed and the interruption unit has a low impedance and - when a current that exceeds a first current value is determined, in particular the first current value is exceeded for a first time limit, the electronic interruption unit comes to have a high impedance and the mechanical isolating contact unit (MK) remains closed, - when a current that exceeds a second current value for a second time limit is determined, the electronic interruption unit comes to have a high impedance and the mechanical isolating contact unit (MK) is opened, - when a current that exceeds a third current value is determined, the electronic interruption unit comes to have a high impedance and the mechanical isolating contact unit (MK) is opened.

17. Circuit breaker device (SG) according to one of the preceding patent claims, characterized in that the control unit (SE) has a microcontroller.