Circuit breaker device and method

Abstract

The invention relates to a circuit breaker device for low-voltage AC circuits, comprising: - a housing (GEH) having at least two grid-side connections and at least two load-side connections for connecting at least two conductors of the low-voltage AC circuit, - a mechanical isolating contact unit (MK) which is connected in series with an electronic interruption unit (EU), - a first current sensor unit (SI1) for determining a level of a current in the at least two conductors of the low-voltage AC circuit which are connected to the circuit breaker device, - the circuit breaker device is designed in such a way that, if the level of the current exceeds current limit values or current / time limit values, a process for preventing a current flow is initiated. For a detected intrinsic defect of the circuit breaker device, this can be configured to determine whether: a) the contacts of the mechanical isolating contact unit (MK) are opened or b) the semiconductor-based switching elements are switched to a high-impedance state by the electronic interruption unit (EU), or c) the intrinsic defect is signalled.

Description

[0001] 202422269

[0002] 1

[0003] Description

[0004] Protective switching device and procedure

[0005] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included.

[0006] The invention relates to the technical field of a protective switching device for a low-voltage alternating current circuit with an electronic interruption unit and a method for a protective switching device for a low-voltage alternating current circuit with an electronic interruption unit.

[0007] 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.

[0008] Low-voltage AC circuits, networks, or installations refer to circuits with rated currents of up to 125 amperes, or more specifically, up to 63 amperes. Low-voltage AC circuits specifically 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.

[0009] Miniature circuit breakers (MCBs) are long-established overcurrent protection devices used in electrical installations in low-voltage AC circuits. 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.

[0010] 2

[0011] Unlike miniature circuit breakers (MCBs), power circuit breakers are designed for currents greater than 125 A, and sometimes even as low as 63 A. MCBs are therefore 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 rail).

[0012] 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.

[0013] 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 AC 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 disconnect contact unit, particularly with isolating characteristics according to relevant standards for low-voltage AC circuits. The contacts of the mechanical disconnect contact unit are connected in series with the electronic interruption unit, meaning that the current of the low-voltage AC circuit to be protected is routed through both the mechanical disconnect contact unit and the electronic interruption unit.

[0014] The invention relates in particular to low-voltage alternating current circuits with an alternating voltage, usually a time-dependent sinusoidal alternating voltage with frequency f. The time dependence of the instantaneous voltage value u(t) of the alternating voltage is given by the equation:

[0015] u(t) = II * sin (2TT * f * t)202422269

[0016] 3

[0017] described. Whereby:

[0018] u(t) = instantaneous voltage value at time t

[0019] U = Amplitude of the voltage

[0020] A harmonic alternating voltage can be represented by the rotation of a phasor whose length corresponds to the amplitude (II) of the voltage. The instantaneous displacement is the projection of the phasor onto a coordinate system. One oscillation period corresponds to one full rotation of the phasor, and its full angle is 2TT (2π) or 360°. The angular frequency is the rate of change of the phase angle of this rotating phasor. The angular frequency of a harmonic oscillation is always 2TT times its frequency, i.e.,

[0021] w = 2TT*f = 2TT / T = angular frequency of the alternating voltage

[0022] (T = period of the oscillation)

[0023] The angular frequency (w) is often preferred over the frequency (f), since many formulas in oscillation theory can be represented more compactly using the angular frequency due to the occurrence of trigonometric functions whose period is by definition 2TT:

[0024] u(t) = U * sin(wt)

[0025] In the case of angular frequencies that are not constant over time, the term instantaneous angular frequency is also used.

[0026] In the case of a sinusoidal, especially time-constant, alternating voltage, the time-dependent value of the angular velocity w and the time t corresponds to the time-dependent angle cp(t), which is also called the phase angle cp(t).

[0027] This means the phase angle cp(t) periodically traverses the range O...2TT or 0°...360°. This means the phase angle periodically assumes a value between 0 and 2TT or 0° and 360° (cp = n*(0...2TT) or cp = n*(0°...360°), due to periodicity; simplified: (p = O...2TT or (p = 0°...360°).

[0028] The instantaneous voltage value u(t) therefore refers to the instantaneous value of the voltage at time t, i.e., in the case of a sinusoidal (periodic) alternating voltage, the value of the voltage at the phase angle cp (cp = 0...2TT or cp = 0°...360°, of the respective period). In contrast to the instantaneous voltage value or instantaneous current value, there is 202422269

[0029] 4

[0030] The RMS value of the voltage or the RMS value of the current. In electrical engineering, the RMS value is understood to be the root mean square of a time-varying physical quantity. The term is preferably applied to alternating quantities.

[0031] The effective value of a variable quantity is equal to the value of an equivalent quantity that would dissipate the same amount of electrical energy in a resistive load over a representative period of time. An equivalent statement can be made for electrical power. The effective value depends on both the peak value and the waveform. In English, the effective value is denoted by RMS (abbreviation for Root Mean Square).

[0032] The object of the present invention is to improve a protective switching device of the type mentioned above, in particular to achieve greater flexibility of the protective switching device, especially better adaptability to different customer requirements or

[0033] Applications.

[0034] This problem is solved by a protective switching device having the features of claim 1, and by a method according to claim 18.

[0035] According to the invention, a protective switching device for the protection of a low-voltage alternating current electrical circuit is proposed, comprising:

[0036] - an enclosure with at least two mains-side connections and at least two load-side connections, for connecting at least two conductors (in particular phase conductors and neutral conductors) of the low-voltage alternating current circuit,

[0037] - a mechanical isolating contact unit which can be switched by a closed state of the contacts to allow current flow in the conductors of the low-voltage alternating current circuit or by an open state of the contacts to prevent current flow by means of galvanic isolation of the conductors of the low-voltage alternating current circuit, - that the mechanical isolating contact unit is connected in series with an electronic interruption unit,

[0038] - that the electronic interruption unit can be switched by semiconductor-based switching elements into a high-resistance state of the switching elements to prevent current flow in at least one conductor or a low-resistance state of the switching elements to allow current flow in the low-voltage alternating current circuit,

[0039] - a first current sensor unit, for determining the magnitude of a current of the

[0040] low-voltage alternating current circuit, 202422269

[0041] 5

[0042] - a control unit connected to the first current sensor unit, the mechanical disconnect contact unit and the electronic interrupt unit,

[0043] - that the protective switching device is designed in such a way that, if the current exceeds current limits or current time limits, a current flow prevention is initiated, in particular by an open state of the contacts or (and) a high-resistance state of the switching elements,

[0044] According to the invention, the protective switching device is designed such that a configuration device (in particular connected to the control unit) is provided with which it can be configured for a detected intrinsic defect (of a unit) of the protective switching device whether: a) the contacts of the mechanical isolating contact unit are opened or

[0045] b) the semiconductor-based switching elements switch the electronic interruption unit into a high-impedance state or

[0046] c) the intrinsic defect is signaled.

[0047] This has the particular advantage that, upon detecting an internal defect in a unit (self-defect), the protective switching device can react differently, depending on the requirements. Different actions may be advantageous in different applications.

[0048] There are applications where the electrical safety of the protected low-voltage AC circuit is the highest priority, e.g., in kindergartens, primary schools, public buildings, etc. For these applications, the protective switching device can be configured so that upon detection of a fault (self-defect), this protective switching device always enters a safe state, such as the OFF state with the contacts of the mechanical isolating contact unit open.

[0049] There are applications where the availability of electrical power is paramount, such as industrial plants in the process industry or similar environments. For these applications, the protective switching device can be configured so that, upon detecting a fault, it remains permanently ON (closed contacts and low-resistance switching elements) and merely signals the fault itself, for example, by sending a warning or information message. The responsible electrical power distribution specialist can then replace the defective device.

[0050] Depending on the type of inherent defect, a different configuration of the protective switching device behavior can also be implemented, e.g., a high-impedance state of the

[0051] Switching elements. 202422269

[0052] 6

[0053] An intrinsic defect is a defect in a unit of the protective switching device, in particular an (intrinsic) defect of the electronic interruption unit, the current sensor unit or (and) the control unit, and in particular also an (intrinsic) defect of the mechanical

[0054] T disconnect contact unit.

[0055] The protective switching device may include a differential current sensor unit connected to the control unit for determining the magnitude of a fault current in the at least two conductors of the low-voltage AC circuit connected to the protective switching device. The protective switching device is designed such that if the magnitude of the fault current exceeds the fault current limits or fault current time limits, current flow is prevented. A failure of any component of the protective switching device also constitutes a failure of the differential current sensor unit.

[0056] The protective switching device may include a first voltage sensor unit connected to the control unit for determining the voltage level of at least two conductors of the low-voltage AC circuit connected to the protective switching device. A failure of any component of the protective switching device is also a (self-)defect of the voltage sensor unit.

[0057] Further advantageous embodiments of the invention are specified in the dependent claims and in the exemplary embodiment.

[0058] In an advantageous embodiment of the invention, the mechanical disconnect contact unit is assigned to the load-side connection and the electronic interruption unit to the network-side connection. In particular, the mechanical disconnect contact unit can be operated by a mechanical handle to switch the contacts open or closed.

[0059] This has the particular advantage that a structure for a protective switching device is provided in which the functionality of the protective switching device is ensured even when the contacts of the mechanical isolating contact unit are open, so that the protective switching device is supplied with energy at all times.

[0060] In an advantageous embodiment of the invention, the contacts of the mechanical disconnect contact unit can be opened, but not closed, by the control unit.

[0061] 7

[0062] This has the particular advantage of providing a highly reliable protective switching device. This prevents the contacts from being accidentally closed due to a fault, such as a software error.

[0063] The mechanical disconnect contact unit is advantageously operable via a mechanical handle. Switching on and off using the electronic interruption unit is not (directly) possible at the protective switching device.

[0064] In an advantageous embodiment of the invention, the current flow is prevented by a high-resistance state of the switching elements of the electronic interruption unit.

[0065] This has the particular advantage of enabling a rapid prevention of current flow.

[0066] In an advantageous embodiment of the invention, the current flow is avoided by an open state of the contacts of the mechanical isolating contact unit.

[0067] This has the particular advantage of enabling galvanically isolated prevention of current flow.

[0068] In an advantageous embodiment of the invention, the protective switching device is designed such that the method of preventing current flow is configurable.

[0069] This has the particular advantage that the protective switching device can be flexibly configured in the event of overcurrent or short-circuit events in the low-voltage circuit.

[0070] In an advantageous embodiment of the invention, a display unit connected to the control unit is provided, which has visible display means on the protective switching device for signaling the information (self-defect) (the signaling of the information is carried out by the optical display unit on the protective switching device).

[0071] This has the particular advantage that a visualization of an inherent defect of the protective switching device is provided at the protective switching device itself.

[0072] In an advantageous embodiment of the invention, a communication unit connected to the control unit is provided, such that the signaling of the information is effected by communication, in particular (wireless or) conductorless communication.

[0073] 8

[0074] This has the particular advantage that a fault in the protective switching device can be signaled to, for example, a higher-level monitoring or management system, so that a service technician can be informed (quickly).

[0075] In an advantageous embodiment of the invention, an input unit is provided which is connected to the control unit for configuring the protective switching device, in particular for the configuration in case of a detected self-defect (of a unit) of the protective switching device.

[0076] This has the particular advantage that a configuration is provided on the protective switching device.

[0077] In an advantageous embodiment of the invention, the protective switching device (in particular the configuration device) is designed such that, for each unit, it can be configured whether:

[0078] a) the contacts of the mechanical isolating contact unit are opened or

[0079] b) the semiconductor-based switching elements switch the electronic interruption unit into a high-impedance state or

[0080] c) the intrinsic defect is signaled.

[0081] This has the particular advantage that an individual configuration of the protective switching device's behavior can be configured for each unit (in the event of a detected self-defect of the unit). For example, a first behavior can be configured in the event of a self-defect of the electronic interruption unit, and a (different) second behavior can be configured in the event of a self-defect of the first current sensor unit.

[0082] In an advantageous embodiment of the invention, if a fault is detected in a unit of the protective switching device and the contacts of the mechanical isolating contact unit are configured to be open, it can further be configured that the switching capability of the contacts to a closed state is not enabled (blocked).

[0083] This has the particular advantage that the protective switching device enters a safe state, so that a protective switching device with an inherent defect cannot be switched on again / the contacts cannot be closed. This increases the safety in the circuit to be protected by the protective switching device.

[0084] In an advantageous embodiment of the invention, after acknowledgment of the inherent defect and (a renewed test for the presence of the inherent defect) if the inherent defect is not present, the contacts can be switched to a closed state.

[0085] 9

[0086] This has the particular advantage of increasing flexibility if the self-defect detection is faulty (false positive). This can be caused, for example, by short-term disturbances and abnormal conditions in the grid, such as deviations in grid voltage quality or an unacceptably high electromagnetic interference.

[0087] Similarly, an unauthorized bypass of the protective device can be identified as a defect, since the circuit can no longer be switched off due to the bypass. However, since this does not constitute a defect in the device itself, the device's functionality can be restored after acknowledgment and retesting.

[0088] In an advantageous embodiment of the invention, it can further be configured that, in a configuration where the contacts of the mechanical disconnect contact unit are opened, or in a configuration where the semiconductor-based switching elements of the electronic interruption unit are switched to a high-impedance state, the intrinsic defect is optionally signaled, either in the case of opening the contacts of the mechanical disconnect contact unit or in both cases.

[0089] This has the particular advantage that (in addition) a notification of the self-defect is made, either at the protective switching device or / and via a communication unit to, for example, a higher-level management system.

[0090] In an advantageous embodiment of the invention, if a fault is detected in a unit of the protective switching device and the semiconductor-based switching elements are switched to a high-impedance state, it can further be configured that the switching capability to a low-impedance state of the switching elements is not enabled (blocked).

[0091] This has the particular advantage that the protective switching device assumes a safe state, so that a protective switching device with an inherent defect reliably prevents current flow, thus ensuring safety in the circuit to be protected by the protective switching device.

[0092] In an advantageous embodiment of the invention, it can further be configured so that, in the absence of the inherent defect, the switching elements can be switched to the low-resistance state.

[0093] This has the particular advantage of increasing flexibility if the self-defect detection is falsely positive. This can be caused, for example, by short-term disturbances and abnormal conditions in the network, such as deviations in the network voltage quality or an unacceptably high level of EMC interference. In this way, the system can (automatically) switch back to the low-impedance state.

[0094] 10

[0095] In an advantageous embodiment of the invention, it can further be configured that, in the absence of the intrinsic defect and an acknowledgment of the intrinsic defect, switching to the low-resistance state of the switching elements is possible (release given).

[0096] This has the particular advantage of increasing flexibility, for example, if the self-defect detection is falsely positive. This can be caused by short-term disturbances and abnormal conditions in the network, such as deviations in the network voltage quality or an unacceptably high electromagnetic interference. After confirmation (acknowledgment), the system can then switch back to the low-impedance state.

[0097] In an advantageous embodiment of the invention, if a self-defect of a unit of the protective switching device is detected and a configuration is in place to signal the self-defect, it can further be configured that operation with a self-defect of the protective switching device is only possible for a period of time, in particular a configurable one.

[0098] This has the particular advantage that, for applications where the availability of electrical power is paramount, such as industrial plants in the process industry or similar, the protective switching device remains in the ON state even when a fault is detected, signals (sends) a warning (or information), and such emergency operation is limited in time to provide residual safety. For example, the emergency operation can be in effect for an adjustable period (e.g., up to two weeks). During this time, emergency operation with limited functionality and safety can be carried out. The responsible electrical power distribution specialist can replace the defective device within this period.

[0099] According to the invention, a corresponding method for a protective switching device for a low-voltage alternating current circuit with electronic (semiconductor-based) switching elements is claimed, offering the same and further advantages.

[0100] The method for a protective switching device for the protection of a low-voltage alternating current electrical circuit with at least two conductors, comprising:

[0101] - a housing with at least two mains-side connections and at least two load-side connections, for connecting the at least two conductors of the low-voltage alternating current circuit,

[0102] - a mechanical isolating contact unit which, by means of a closed state of the contacts, allows current flow in the conductors of the low-voltage alternating current circuit or an open state of the contacts, prevents current flow by means of a 202422269

[0103] 11

[0104] galvanic isolation of the conductors of the low-voltage alternating current circuit is switchable, - that the mechanical isolating contact unit is connected in series with an electronic interruption unit,

[0105] - that the electronic interruption unit can be switched by semiconductor-based switching elements into a high-resistance state of the switching elements to prevent current flow in at least one conductor or a low-resistance state of the switching elements to allow current flow in the low-voltage alternating current circuit,

[0106] - a first current sensor unit, for determining the magnitude of a current in the at least two conductors of the low-voltage alternating current circuit connected to the protective switching device, - that if the magnitude of the current is exceeded above current limit values ​​or current time limit values, a prevention of current flow is initiated.

[0107] According to the invention, for a detected inherent defect (e.g. of a unit) of the protective switching device, it can be configured whether:

[0108] a) the contacts of the mechanical isolating contact unit (MK) are opened or

[0109] b) the semiconductor-based switching elements of the electronic interruption unit (EU) are switched into a high-impedance state or

[0110] c) the intrinsic defect is signaled.

[0111] All embodiments, both in dependent form relating back to patent claim 1 or

[0112] 18, as well as referring back only to individual features or combinations of features of patent claims, in particular also a reference of the dependent arrangement claims to the independent method claim (and vice versa), result in an improvement of a protective switching device, in particular an improvement of the safety of a protective switching device.

[0113] 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.

[0114] The drawing shows:

[0115] Figure 1 shows a representation of a protective switching device.

[0116] Figure 1 shows a representation of a protective switching device SG for the protection of a low-voltage alternating current electrical circuit with a housing GEH, comprising: 202422269

[0117] 12

[0118] - a mains-side neutral conductor connection NG, a mains-side phase conductor connection LG, a load-side neutral conductor connection NL, a load-side phase conductor connection LL for at least two conductors of the low-voltage alternating current circuit; in particular a phase conductor and a neutral conductor, wherein the phase conductor is routed inside the housing as (protection switch-internal) phase conductor L and the neutral conductor is routed inside the housing as (protection switch-internal) neutral conductor N,

[0119] A power source is usually connected to the grid side.

[0120] A consumer is usually connected to the load side;

[0121] - a (two-pole) mechanical disconnect contact unit MK with load-side connection points APLL, APNL and network-side connection points APLG, APNG,

[0122] where 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 and APLL are connected to the load-side neutral and phase conductor connections NL and LL, respectively, so that the opening of contacts KKN and KKL to prevent current flow or the closing of the contacts to allow current flow in the low-voltage AC circuit can be switched.

[0123] The mechanical disconnect contact unit can also be designed as a single-pole mechanical disconnect contact unit, i.e. with one contact, wherein the contact KKL is preferably arranged in the (protective switch internal) phase conductor L,

[0124] - an electronic interruption unit EU, in particular a single-pole unit, (which in the case of a single-pole design is in particular arranged in the (protective switching device internal) phase conductor L,) with a network-side connection point EUG, which is in electrical connection with the network-side phase conductor connection LG, and

[0125] a load-side connection point EUL which is electrically connected to the network-side connection point APLG of the mechanical disconnect contact unit MK, wherein the electronic interruption unit 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 alternating current circuit by means of semiconductor-based switching elements,

[0126] - a first current sensor unit SI1, for determining the magnitude of a current in the low-voltage alternating current circuit, which is in particular arranged in the phase conductor L, - a control unit SE, which is connected to the first current sensor unit SI1, the mechanical disconnect contact unit MK and the electronic interruption unit EU, wherein, if the magnitude of the current is exceeded, current and / or current time limits (dh202422269)

[0127] 13

[0128] (when a current of a certain magnitude is present for a certain time) a prevention of current flow in the low-voltage alternating current circuit is initiated.

[0129] Furthermore, a first voltage sensor unit SUA connected to the control unit SE can be provided, which determines the voltage level, in particular instantaneous voltage levels, of the low-voltage AC circuit, especially at the mains-side terminals LG, NG, specifically between the mains-side neutral terminal NG and the mains-side phase terminal LG. Advantageously, the electronic interruption unit EU switches to the low-impedance state when the instantaneous voltage level falls below a first voltage limit, which is in particular less than or equal to 50 volts (or 25 volts or 10 volts).

[0130] The same principle applies to the high-impedance switching of the electronic interruption unit EU. When switching the electronic interruption unit EU at high impedance, a first current limit can be used as an alternative to the first voltage limit.

[0131] In general, the mechanical disconnect contact unit MK and the electronic interruption unit EU form a series circuit. This series circuit is connected to both the mains-side and load-side terminals (in this case, the neutral conductor passes through the (imaginary) two-pole electronic interruption unit, whereby the neutral conductor is, or can be, free of semiconductor-based switching elements). The mechanical disconnect contact unit MK can advantageously be assigned to the load-side terminal and the electronic interruption unit EU to the mains-side terminal, as shown in Figure 1. The mechanical disconnect contact unit MK can be operated by a mechanical handle HH to switch the opening or closing of contacts, similar to a conventional miniature circuit breaker (MCB).

[0132] The control unit SE can contain a microcontroller MP (microcontroller unit).

[0133] Furthermore, a second voltage sensor unit SUB connected to the control unit SE may be provided, which determines the voltage level between the grid-side connection point EUG and the load-side connection point EUL of the electronic interruption unit EU.

[0134] A measuring impedance ZM can be connected between the mains-side connection points APLG and APNG of the mechanical disconnect contact unit MK. The measuring impedance ZM202422269

[0135] 14

[0136] The measuring impedance can be, for example, an electrical resistor and / or capacitor. It 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.

[0137] In the example shown in Figure 1, the electronic interruption unit EU is single-pole, located 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. In a single-pole version of the protective switching device, this connection, as well as the neutral conductor contact KKN of the mechanical disconnect contact unit, can be omitted.

[0138] 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.

[0139] The mechanical disconnect contact unit MK can be operated by a mechanical handle HH on the protective switching device SG to manually open or close the contacts KKL and KKN. The mechanical handle HH indicates (specifically through a mechanical connection between the contacts and the handle) the switching state (open or closed) of the contacts of the mechanical disconnect contact unit MK on the protective switching device.

[0140] 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 ("permanent slip"), i.e., a blockage exists (the contacts cannot be switched to a closed state).

[0141] 15

[0142] The protective switching device SG has a power supply NT, for example, a power supply unit. In particular, the power supply NT is provided for the control unit SE, as indicated by a connection between the power supply NT and the control unit SE in Figure 1. The power supply NT is (on the other hand) connected to the mains-side neutral conductor terminal NG and the mains-side phase conductor terminal LG. A fuse SS, in particular a cartridge fuse, and / or a switch can advantageously be provided in the connection to the mains-side neutral conductor terminal NG (and / or phase conductor terminal LG).

[0143] In the case of a purely single-pole protective switching device, the power supply is provided by an external power source / additional connections.

[0144] 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.

[0145] Low resistance refers to a state in which the current value specified on the protective switching device could flow.

[0146] In particular, low resistance values ​​are meant to be less than 10 ohms, preferably less than 1 ohm, 100 milliohms, 10 milliohms, 1 milliohm or less.

[0147] The mechanical disconnect contact unit MK can, in one variant, interrupt a single pole. This means that only one conductor (of the two / multiple conductors), specifically the live conductor or phase conductor, is interrupted, i.e., it has a mechanical contact. The neutral conductor is then without contact, i.e., the neutral conductor is directly connected.

[0148] In a second variant of the mechanical disconnect contact unit MK, the neutral conductor also has mechanical contacts, as shown in Figure 1.

[0149] The term "mechanical disconnect contact unit MK" refers specifically to a (standard-compliant) disconnect function, implemented by the disconnect contact unit MK. The following points are included with the disconnect function:

[0150] -Minimum air gap according to standard (minimum distance between contacts),

[0151] - (Mechanical) contact position indicator of the contacts of the mechanical isolating contact unit, -Free release, i.e., actuation to interrupt the contacts of the mechanical isolating contact unit by the handle or control unit is always possible, so that no (permanent) blocking of the contacts in the closed state by the handle is possible, 202422269

[0152] 16

[0153] meant.

[0154] Furthermore, the standard-compliant disconnect function can include the ability to lock the disconnect contact unit or the handle in the switched-on or switched-off state.

[0155] The minimum air gap between the contacts of the isolating contact unit is essentially voltage-dependent. Other parameters include the degree of pollution, the type of field (homogeneous, inhomogeneous), and the air pressure or altitude above sea level.

[0156] There are corresponding regulations and standards for these minimum clearances or creepage distances. These regulations specify, for example, the minimum clearance for an inhomogeneous and a homogeneous (ideal) electric field, depending on the degree of pollution, in the case of air required for impulse voltage withstand capability. Impulse voltage withstand capability is the resistance to being applied when a corresponding impulse voltage is applied. Only if this minimum length (minimum distance) is present does the isolating contact unit or protective switching device exhibit an isolating function (isolating property).

[0157] For the purposes of the invention, the standards DIN EN 60947 and IEC 60947 are relevant for the separator function and its properties, and reference is made to them here.

[0158] The isolating contact unit is advantageously characterized by a minimum air gap between the open isolating contacts in the OFF position (open position, contacts open), depending on the rated impulse withstand voltage and the degree of pollution. The minimum air gap is, in particular, between (at a minimum) 0.01 mm and 14 mm.

[0159] In particular, the minimum air gap is advantageously between 0.01 mm at 0.33 kV and 14 mm at 12 kV, especially for pollution degree 1 and especially for inhomogeneous fields.

[0160] The pollution levels and field types correspond to those defined in the standards. This advantageously allows for the creation of a standard-compliant protective switching device dimensioned according to the rated impulse withstand voltage.

[0161] The term "mechanical isolating contact unit" specifically does not refer to a relay contact.

[0162] Furthermore, a communication unit COM (especially wireless or cableless) is provided, which is connected to or part of the control unit SE. 202422269

[0163] 17

[0164] Furthermore, a display unit AE is provided. The display unit AE can be designed as a combined display and input unit. The display unit AE (display and input unit) is connected to the control unit SE or is part of it. The display unit AE has visible indicators on the protective switching device, in particular for signaling information.

[0165] The protective switching device SG can include a differential current sensor unit ZCT for determining the magnitude of a fault current (or differential current) of the neutral and phase conductors of the low-voltage AC circuit (caused by leakage currents of the phase conductor L or neutral conductor N to earth or the protective conductor PE). In the example shown in Figure 1, the differential current sensor unit ZCT is arranged between the electronic interruption unit EU and the mechanical disconnect contact unit MK. Alternatively, it can be arranged between the mechanical disconnect contact unit MK and the load-side neutral and phase conductor connections NL, LL, or alternatively between the electronic interruption unit EU and the network-side connections NG, LG.The ZCT differential current sensor unit determines the magnitude of the fault current (fault current refers to the differential current; in the case of residual current circuit breakers according to the state of the art, fault current refers to the differential current; fault current does not refer to an overcurrent or short-circuit current (between phase conductor and neutral conductor) in the low-voltage AC circuit) of the conductors of the low-voltage AC circuit that are routed through the protective switching device (and are to be protected). The example given is for a single-phase AC circuit with neutral conductor N and phase conductor L.

[0166] The differential current sensor unit ZCT can be a classic summation current transformer. The primary side of the summation current transformer is formed by the conductors of the low-voltage AC circuit (in this example, phase conductor L and neutral conductor N) (primary winding = first winding). The secondary side (secondary winding = second winding) of the summation current transformer is connected to the control unit SE.

[0167] As shown in Figure 1, a configuration memory KS is provided, which is connected to the control unit SE. Configurations / configuration data of the (configured behavior of the) protective switching device can be stored here.

[0168] The protective switching device SG has a configuration device (connected to the control unit (SE)) which can be used to configure, in the event of a detected intrinsic defect of a unit of the protective switching device, whether:

[0169] a) the contacts of the mechanical isolating contact unit (MK) are opened or 202422269

[0170] 18

[0171] b) the semiconductor-based switching elements of the electronic interruption unit (EU) are switched into a high-impedance state or

[0172] c) the intrinsic defect is signaled.

[0173] For further configuration variants, reference is made to the advantageous embodiments already mentioned above and the following more specific examples.

[0174] The configuration setup can be part of the configuration memory KS as shown in Figure 1.

[0175] The invention will be described in more detail below, partly using different words.

[0176] A protective switching device according to the invention has three operationally relevant switching states:

[0177] • OFF state: mechanical contacts open, semiconductor-based switching elements in a high-resistance state

[0178] • ON state: mechanical contacts closed, semiconductor-based switching elements in low-resistance state

[0179] • STANDBY state: mechanical contacts closed, semiconductor-based switching elements in a high-resistance state

[0180] A protective switching device according to the invention can have self-diagnostic tools. These are devices and methods for detecting defects in the units (or...).

[0181] Components) of the protective switching device. For example, a protective switching device according to the invention can determine, via self-diagnostic tools, whether the electronic interruption unit EU, the first current sensor unit, the control unit, a voltage sensor unit, a differential current sensor unit, and / or the mechanical disconnect contact unit are functional or defective. A defect in one of the aforementioned units (depending on its presence) is referred to as a self-defect.

[0182] Methods for defect detection are described in parallel patent applications.

[0183] A protective switching device according to the invention can have several functions, depending on the application. A defect in the protective switching device can impair only one or several of these functions. Depending on the affected function and the application, this is more or less critical for the safety of the low-voltage AC circuit to be protected. 202422269

[0184] 19

[0185] A protective switching device (device) according to the invention has the capability, after detecting a defect, to assume one of the aforementioned switching states (ON, STANDBY, OFF). Depending on the application, one of these states may be advantageous.

[0186] In many applications, plant and personnel protection has the highest priority, while in other applications, plant availability is paramount. The present invention provides a solution for reconfiguring the protective switching device, thereby offering increased flexibility.

[0187] Depending on the type of inherent defect, different configurations of device behavior can be set, generally:

[0188] 1) The protective switching device switches to the OFF state and does not allow changes to the STANDBY or ON state. The contacts can therefore no longer be closed, at least as long as the fault in the protective switching device exists and is detected. This behavior ensures maximum safety for the protected circuit.

[0189] 2) The protective switching device switches to the STANDBY state and does not allow changes to the ON state. This can be advantageous, for example, if an acknowledgement / reset is performed via the communication unit and the protective switching device can be set back to the ON state. This can be beneficial for applications where the availability of electrical power is critical.

[0190] 3) The protective switching device does not change its switching state. The fault is merely signaled (reported). A service technician is dispatched to replace the protective switching device. Another option is that this state only persists for a certain period of time, e.g., two weeks. Afterwards, the protective switching device then switches, for example, to a high-resistance state.

[0191] 4) The protective switching device switches from the ON state to the STANDBY state and performs self-monitoring cyclically or continuously. If the originally detected fault is no longer detected, the protective switching device automatically switches back to the ON state.

[0192] 5) The protective switching device signals (reports) the detection of an internal defect via a communication unit (communication interface). 202422269

[0193] 20

[0194] In some cases, fault detection can produce false positives. This can be caused, for example, by short-term disturbances and abnormal network conditions, such as deviations in mains voltage quality or excessively high EMC interference. Another possible cause is an unintended modification to the circuit around the protective device, such as a low-resistance bridge on one pole. In such cases, it can be advantageous to switch to standby mode upon fault detection and continue self-monitoring. Furthermore, it can be beneficial if the protective device automatically switches to the on state afterward if the previously detected fault is no longer present.

[0195] As mentioned, possible reactions to an inherent defect are very diverse. The advantageous behavior of the protective switching device in the event of a defect depends on the application and the type of defect.

[0196] Possible device defects could include:

[0197] • Failure / defect in the current sensor unit / current measurement

[0198] • Failure / defect in the voltage sensor unit / voltage measurement

[0199] • Failure / defect in the electronic interruption unit (gate unit, power semiconductor, surge protection, etc...)

[0200] • Failure / defect in the differential current sensor unit / summation current transformer

[0201] According to the invention, the way the protective switching device reacts to a detected internal defect can be configured. The reaction to an internal defect can be set according to the configuration options below. In one embodiment, it is possible to set a separate configuration option for each type of defect detectable by the protective switching device.

[0202] The selection of configuration options is carried out, for example, via a configuration device, whereby the communication unit (communication interface) can also serve as the configuration device, with, for example, an operating option on the protective switching device (e.g., touchscreen). Accordingly, the configuration must be carried out by qualified personnel. This can be ensured, for example, by appropriate password protection or similar measures.

[0203] Configuration option 1 - open contacts of the mechanical disconnect contact unit (disconnect) in case of component defect 202422269

[0204] 21

[0205] 1) When this setting is selected, the protective switching device will, for example, in the event of a self-defect:

[0206] a.) Do not allow switching to the STANDBY and ON states while the device is OFF.

[0207] Preventing changes to the STANDBY and ON states is achieved, for example, by not enabling (blocking) the closing of the contacts (blocking the contacts) and, for example, by blocking the control pulses for the electronic interruption unit. b.) Switching from the STANDBY or ON state to the OFF state and preventing changes to the STANDBY and ON states.

[0208] 2) The protective switching device signals (explicitly indicates) that it has detected an internal defect and is therefore in the OFF state.

[0209] 3) Optionally, the detected intrinsic defect is signaled (reported) via the communication unit.

[0210] 4) If the self-defect message is acknowledged and the self-defect is no longer detected, then: a. switching to the STANDBY and ON states can be allowed again and

[0211] b. the signaling is deactivated.

[0212] Configuration option 2 - high-resistance state of the semiconductor-based switching elements at

[0213] 1) When this setting is selected, the protective switching device will, for example, in the event of a self-defect:

[0214] a.) Remain in the OFF or STANDBY state and allow switching between these states. Preventing a switch to the ON state is achieved, for example, by blocking the control pulses for the electronic interruption unit.

[0215] b.) Switch from the ON state to the STANDBY state and again do not allow switching back to the ON state.

[0216] 2) The protective switching device signals (explicitly indicates) that it has detected an intrinsic defect and is therefore in STANDBY mode.

[0217] 3) The detected defect is signaled via the communication unit.

[0218] Configuration option 2.1

[0219] Switching to STANDBY and ON states is allowed again, and signaling (error indication) is deactivated when the fault is no longer detected.

[0220] 22

[0221] Configuration option 2.2

[0222] Switching to the STANDBY and ON states is permitted again and the signaling (error indication) is deactivated when the self-defect is no longer detected and the self-defect signaling (message) has been acknowledged via the communication unit or via an operating element on the protective switching device (acknowledgment of the self-defect).

[0223] Configuration option 3 - Self-defect is signaled (no switching action upon detection of a self-defect)

[0224] 1) When this setting is selected, the protective switching device will remain in its current state in the event of an internal defect and will allow any change between the states OFF, STANDBY and ON.

[0225] 2) The protective switching device signals (explicitly indicates) that it has detected an intrinsic defect.

[0226] 3) The detected intrinsic defect is reported via the communication unit (communication interface).

[0227] 4) If the self-defect message is acknowledged and the self-defect is no longer detected, then the signaling (error indication) is deactivated.

[0228] The invention can advantageously be implemented by a microprocessor with appropriate firmware contained in the control unit.

[0229] After preventing current flow by means of an open state of the contacts of the mechanical isolating contact unit MK, the switching capability of the contacts to a closed state may not be enabled (blocked) by a so-called "permanent slider".

[0230] 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 from them by the person skilled in the art without leaving the scope of protection of the invention.

Claims

202422269 23 Patent claims 1. Protective switching device for low-voltage alternating current circuits, comprising: - an enclosure (GEH) with at least two mains-side connections and at least two load-side connections, for connecting at least two conductors of the low-voltage alternating current circuit, - a mechanical isolating contact unit (MK) which can be switched by a closed state of the contacts to allow current flow in the conductors of the low-voltage alternating current circuit or by an open state of the contacts to prevent current flow by means of galvanic isolation of the conductors of the low-voltage alternating current circuit, - that the mechanical isolating contact unit (MK) is connected in series with an electronic interruption unit (EU), - that the electronic interruption unit (EU) can be switched by semiconductor-based switching elements into a high-resistance state of the switching elements to prevent current flow in at least one conductor or a low-resistance state of the switching elements to allow current flow in the low-voltage alternating current circuit, - a first current sensor unit (SI1) for determining the magnitude of a current in the at least two conductors of the low-voltage alternating current circuit connected to the protective switching device, - a control unit (SE) connected to the first current sensor unit (SI1), the mechanical disconnect contact unit (MK) and the electronic interruption unit (EU), - that the protective switching device is designed in such a way that, if the current exceeds current limits or current time limits, a current flow prevention is initiated, characterized by that the protective switching device has a configuration device with which it can be configured, in the event of a detected intrinsic defect of the protective switching device, whether: a) the contacts of the mechanical isolating contact unit (MK) are opened or b) the semiconductor-based switching elements of the electronic interruption unit (EU) are switched into a high-impedance state or c) the intrinsic defect is signaled.

2. Protective switching device (SG) according to claim 1, characterized by that an intrinsic defect is a defect of a unit of the protective switching device, in particular the 202422269 24 electronic interruption unit, current sensor unit or control unit, and especially the mechanical disconnect contact unit.

3. Protective switching device (SG) according to claim 1 or 2, characterized by that a differential current sensor unit (ZCT) connected to the control unit (SE) is provided for determining the magnitude of a fault current of the at least two conductors of the low-voltage alternating current circuit connected to the protective switching device (SG), - that the protective switching device is designed in such a way that if the magnitude of the fault current is exceeded above fault current limit values ​​or fault current time limit values, a current flow prevention is initiated, that a defect in one unit is also a defect in the differential current sensor unit (ZCT).

4. Protective switching device (SG) according to one of the preceding patent claims, characterized by that a first voltage sensor unit (SUA) connected to the control unit (SE) is provided for determining the level of a voltage of the at least two conductors of the low-voltage alternating current circuit connected to the protective switching device (SG), and that a fault in one unit is also a fault of the voltage sensor unit (SUA).

5. Protective switching device (SG) according to one of the preceding patent claims, characterized by that the protective switching device is designed in such a way that, for each unit, it can be configured whether: a) the contacts of the mechanical isolating contact unit (MK) are opened or b) the semiconductor-based switching elements of the electronic interruption unit (EU) are switched into a high-impedance state or c) the intrinsic defect is signaled.

6. Protective switching device (SG) according to one of the preceding patent claims, characterized by that in the event of a detected inherent defect in a unit of the protective switching device and a configuration that opens the contacts of the mechanical isolating contact unit (MK), it can further be configured that the contacts cannot be switched to a closed state. 202422269 25 7. Protective switching device (SG) according to claim 6, characterized by that after acknowledgment of the inherent defect and in the absence of the inherent defect, the contacts can be switched to a closed state.

8. Protective switching device (SG) according to one of the preceding patent claims, characterized by that it can further be configured that, in a configuration where the contacts of the mechanical disconnect contact unit are opened, or in a configuration where the semiconductor-based switching elements of the electronic interrupt unit are switched to a high-impedance state, the intrinsic defect is signaled either or in both cases.

9. Protective switching device (SG) according to one of the preceding patent claims, characterized by that in the event of a detected intrinsic defect of a unit of the protective switching device and a configuration that the semiconductor-based switching elements switch the electronic interruption unit (EU) into a high-impedance state, it can further be configured, that the switching capability to a low-resistance state of the switching elements is not enabled.

10. Protective switching device (SG) according to claim 9, characterized by that it can also be configured so that, in the absence of an inherent defect, switching to the low-resistance state of the switching elements is possible.

11. Protective switching device (SG) according to claim 9 or 10, characterized by that it can also be configured so that, in the absence of a self-defect and an acknowledgment of the self-defect, switching to the low-resistance state of the switching elements is possible.

12. Protective switching device (SG) according to one of the preceding patent claims, characterized in that, that in the event of a detected intrinsic defect of a unit of the protective switching device and a 202422269 26 Configuration that signals the self-defect, and furthermore, it can be configured that operation with a self-defect of the protective switching device is only possible for a specific, in particular configurable, period of time.

13. Protective switching device (SG) according to one of the preceding patent claims, characterized by that an optical display unit is provided which is connected to the control unit (SE) such that the signaling of the information by the optical display unit takes place at the protective switching device.

14. Protective switching device (SG) according to one of the preceding patent claims, characterized by that a communication unit is provided which is connected to the control unit (SE) such that the signaling of the information takes place through communication, in particular wireless communication.

15. Protective switching device (SG) according to one of the preceding patent claims, characterized by that an input unit is provided which is connected to the control unit (SE) for the configuration of the protective switching device, in particular for the configuration in case of detected self-defect of a unit of the protective switching device.

16. Protective switching device (SG) according to one of the preceding patent claims, characterized by that the mechanical disconnect contact unit (MK) is assigned to the load-side connection.

17. Protective switching device (SG) according to one of the preceding patent claims, characterized by that the contacts of the mechanical isolating contact unit (MK) can be opened by the control unit (SE), but not closed.

18. Method for a protective switching device for low-voltage alternating current circuits, comprising: - an enclosure (GEH) with at least two mains-side connections and at least two load-side connections, for connecting at least two conductors of the low-voltage alternating current circuit, 202422269 27 - a mechanical isolating contact unit (MK) which can be switched by a closed state of the contacts to allow current flow in the conductors of the low-voltage alternating current circuit or by an open state of the contacts to prevent current flow by means of galvanic isolation of the conductors of the low-voltage alternating current circuit, - that the mechanical isolating contact unit (MK) is connected in series with an electronic interruption unit (EU), - that the electronic interruption unit (EU) can be switched by semiconductor-based switching elements into a high-resistance state of the switching elements to prevent current flow in at least one conductor or a low-resistance state of the switching elements to allow current flow in the low-voltage alternating current circuit, - a first current sensor unit (SI1) for determining the magnitude of a current in the at least two conductors of the low-voltage alternating current circuit connected to the protective switching device, - that if the magnitude of the current exceeds current limits or current time limits, a current flow prevention is initiated, characterized by that for a detected self-defect of the protective switching device, it can be configured whether: a) the contacts of the mechanical isolating contact unit (MK) are opened or b) the semiconductor-based switching elements of the electronic interruption unit (EU) are switched into a high-impedance state or c) the intrinsic defect is signaled.

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