Protective switching device and procedure

Abstract

The invention relates to a protective switching device for standard-compliant residual current protection for low-voltage alternating current circuits, wherein - if the magnitude of a fault current is exceeded, the current flow is prevented by a tripping curve forming specific tripping current-time values, - that a standard for residual current / differential current circuit breakers a) current-time tripping limits so that current flow in the low-voltage AC circuit must be avoided, and b) specifies non-tripping current limits so that a current flow must be maintained in the low-voltage alternating current circuit, which indicate a trigger area, - that the actual tripping current-time values ​​are within the tripping range, - that at least one first trigger curve (Robust) and one second trigger curve (Sensitive) can be selected within the trigger range, so that a different triggering behavior can be selected within a normatively designated triggering range.

Description

The invention relates to the technical field of a protective switching device for standard-compliant earth leakage protection for protecting an electrical low-voltage alternating current circuit and to a method for a protective switching device for standard-compliant earth leakage protection of an electrical low-voltage alternating current circuit.Protective switching devices are meant to be low-voltage protective switching devices, in particular residual current circuit breakers. By low voltage is meant voltages up to 1000 volts AC or 1500 volts DC. By low voltage is meant more specifically voltages greater than the low voltage with values of 50 volts AC or 120 volts DC.By low voltage circuits is meant circuits for currents up to 6300 amps, more specifically for currents up to 1600 amps, 1200 amps, 630 amps, 125 amps, 63 amps, 40 amps, 32 amps, 16 amps, 10 amps or 6 amps. The current values mentioned mean, in particular, rated currents (previously rated or / and disconnection currents), i.e. currents which the circuit or a protective switching device can permanently, i.e. without damage, conduct under standardized conditions (such as connection cross sections of the copper conductors and their length) at a defined ambient temperature (such as 40° C.). Such points are defined in relevant product standards (for example DIN EN 60947-2 or 60898-1 and also 61008-1 or 61009-1). This means, in a colloquial manner, the current which is normally conducted at most across the circuit or in which the electrical circuit is usually interrupted, for example by a circuit breaker device such as a circuit breaker or a circuit breaker.Residual current circuit breakers are used in particular for rated current ranges of or up to 6, 10, 16, 25, 32, 40, 63, 80 or 125 amperes.Residual current circuit breakers for electrical circuits, in particular for low-voltage alternating current circuits or installations, are generally known. Residual current circuit breakers are also referred to as FI circuit breakers or residual current devices, RCD for short. Residual current circuit breakers according to the prior art are known from the following patent applications: DE 10 2013 219 292 A1; DE 10 2015 224 890 A1; DE 10 2015 225 423 A1; DE 10 2015 225 910 A1; DE 10 2015 218 911 A1; DE 10 2015 215 456 A1; DE 10 2016 213 875 A1; DE 10 2016 205 101 A1; DE 10 2015 217 040 A1; DE 10 2015 217 267 A1; DE 10 2015 217 411 A1; DE 10 2015 200 714 A1.Residual current circuit breakers determine the current sum (i.e. a sum current or, depending on the current direction / power flow direction, a differential current) between two or more conductors in an electrical circuit, which is normally zero, and interrupt the electrical circuit, which is also referred to as triggering, when a residual current or differential current value is exceeded, i.e. a current sum of not zero, which exceeds a specific differential current limit value (differential current threshold value or response current value or fault current value or fault response current value). More specifically, these residual current values are residual current time (limit) values, i.e., a residual current value exceeding a certain level must also be present for a certain time. Typical differential current threshold values are, for example, 30 mA for personal protection and 300 mA for fire protection (IEC world, 230 volts / 400 volt rated voltage grid). In the case of special requirements for personal protection, a differential current threshold value of 10 mA or 6 mA is typical.Almost all current fault interrupters known to date have a sum current converter, the primary windings of which are formed by the conductors of the circuit and the secondary winding of which emits the sum of current or the differential current or an equivalent of the sum of current / the differential current, for example in the form of a voltage (or current), which is used directly or indirectly for interrupting the electrical circuit.For this purpose, two or more conductors, usually forward and return conductors or phase conductors (=aluminous conductor) and neutral conductor in a single-phase alternating current network, all three phase conductors (=aluminous conductor) or all three phase conductors (=aluminous conductor) and the neutral conductor in a three-phase alternating current network are guided through a current transformer, usually having an annular core made of ferromagnetic material. Only the differential current, i.e. a current differing from forward and reverse current, is converted (or transmitted to the secondary winding) from the conductors. Usually, the current sum in an electric circuit is equal to zero. Fault currents can thus be detected.If, for example, a current flows to ground on the energy sink side or on the load side, a fault current is referred to in this context. This is the case, for example, when a person touches a phase conductor under voltage. In this case, in particular, this current to ground is referred to as the fault current.In contrast, electrical operating means (such as power supplies or frequency converters) can also derive a current to ground on the basis of, for example, so-called Y capacitors. This current is typically referred to as a leakage current.A fault case is present, for example, when an electrically conductive connection exists from a phase conductor or outer conductor of the electrical circuit to the ground. For example, when a person touches the phase conductor.Then, a part of the electric current does not flow back via the neutral conductor or neutral conductor as usual, but via the person and the earth. This residual current can now be detected with the aid of the sum current converter, since the sum of the incoming and return current detected in terms of amount is not zero. A holding magnet release (= holding magnet) or a relay or a release coil, generally an interruption unit, for example with connected mechanisms and contacts, causes an interruption of the circuit, for example at least one, a part or all of the lines.The main function of earth leakage circuit breakers is to protect persons from electrical currents (electrical shock), and also installations, machines or buildings from fire as a result of electrical insulation faults.If the residual current circuit breaker or its sum current converter is designed such that the energy on the secondary side is sufficient for actuating a trip unit or an interruption unit or a trip, then such residual current circuit breakers are mentioned as being independent of the mains voltage; otherwise, they are called mains voltage dependent.If a power supply unit is provided for supplying power to a residual current detection, then these are residual current circuit breakers which are dependent on the mains voltage. These are required, for example, in order to detect fault currents in DC voltage networks and mixed DC / AC networks or in circuits with high frequencies.Residual current circuit breakers are of various types and are identified by letters or letter combinations, such as AC, A, F, G, K, S, B, B+. Each type detects a particular type of fault current. Current earth leakage circuit breakers are currently known to be 2-pole for phase and neutral conductors (L+N), 3-pole for three phase conductors (L 1, L 2, L 3) and 4-pole for three phase conductors and neutral conductors (L 1, L 2, L 3, N).For example, type AC only detect purely sinusoidal fault currents. Type A detects both purely sinusoidal alternating currents and pulsating direct-fault currents. Type F are mixed-frequency-sensitive fault current protection devices. They detect all types of fault currents such as type A, and they are also suitable for detecting fault currents which consist of a frequency mixture of frequencies up to 1 kHz. Type S are selective fault current circuit breakers which can be staggered in rated differential current as well as in trip time. Residual current circuit breakers (=recurrent protection devices) of type B are used, in addition to the detection of the residual current forms of type F, also for the detection of smooth direct fault currents. They are also suitable for fault currents with frequencies of up to 2 kHz. The same conditions apply to residual current circuit breakers of the type B+ as for residual current circuit breakers of the type B. Only the frequency range for detecting residual currents applies to an extended range up to 20 kHz. Fault current circuit breakers of type K contain the characteristic of type A, but it is short-term delayed in its switch-off behavior. Type K are also referred to as super resistant.The product standard DIN EN 61008-1 (FI circuit breaker) and DIN EN 61009-1 (FI / LS switch) describe the behavior of residual current circuit breakers, in particular the limit values for the switch-off times.Circuit breakers with an electronic interrupting unit are relatively novel developments. These comprise a semiconductor-based electronic interruption unit. That is to say that the electrical current flow of the low-voltage alternating current circuit is conducted via semiconductor components or semiconductor switches, which interrupt the electrical current flow or can be switched to conductive. Circuit breakers with an electronic break unit also often have a mechanical break contact system, in particular with break properties according to relevant standards for low-voltage alternating current circuits, wherein the contacts of the mechanical break contact system are connected in series with the electronic break unit, i.e. the current of the low-voltage alternating current circuit to be protected is conducted both (at least partially) via the mechanical break contact system and via the electronic break unit.It is an object of the present invention to improve a circuit breaker, in particular a residual current circuit breaker. In particular, a higher flexibility with regard to the triggering behavior can be achieved.This object is achieved by a circuit breaker with the features of claim 1 and a method with the features of claim 11.According to the invention, a circuit breaker device, in particular a residual current circuit breaker, for protecting an electrical low-voltage alternating current circuit for alternating voltage is proposed, having:a housing having at least two mains-side and at least two load-side connections for at least two conductors of the low-voltage alternating circuit, for connecting at least two conductors of the low-voltage alternating circuit, in particular a phase conductor and a neutral conductor of the low-voltage alternating circuit (alternatively for two phase conductors of the low-voltage alternating circuit; phase conductors (and a neutral conductor)),a differential current sensor unit for determining the magnitude of a fault current (differential current) of the at least two conductors (connected to the circuit breaker device) of the low-voltage alternating current circuit (i.e. for example the differential current between the phase conductor and neutral conductor (alternatively the differential current of two phase conductors)),a mechanical isolation contact unit which is connected in particular (optionally) in series with an electronic interruption unit (wherein the series circuit is connected on the one hand to at least one of the connections on the mains side and on the other hand to at least one of the connections on the load side),the mechanical isolation contact unit can be switched by a closed state of the contacts for a current flow of the conductors of the low-voltage alternating current circuit or an open state of the contacts for a current-flow-preventing galvanic isolation of the conductors of the low-voltage alternating current circuit (i.e. for example phase conductor and neutral conductor or both phase conductors, phase conductors (and neutral conductor))the optional electronic interruption unit can be switched by semiconductor-based switching elements into a high-resistance state of the switching elements in order to avoid a current flow of at least one conductor (for example the phase conductor) or a low-resistance state of the switching elements in order to current flow in the low-voltage alternating current circuit,a control unit which is connected to the differential current sensor unit, the mechanical break contact unit and optionally the electronic interruption unit, wherein, if the magnitude of the fault current is exceeded, specific trigger current time values forming a trigger curve initiate avoidance of a current flow,a standard for residual current / differential current circuit breakers specifies a current time limit values of triggering, so that a current flow in the low-voltage alternating current circuit must be avoided, and b) current limit values of non-triggering, so that a current flow in the low-voltage alternating current circuit must be conducted, which identify a triggering range,the specific trigger current time values lie within the trigger range,the circuit breaker is designed such that at least a first trip curve and a second trip curve can be selected within the trip range for the trip range, so that a different trip behavior can be selected within a trip range identified as normative.That is to say that the circuit breaker has two trip curves, so that either with the first trip curve (with (first) specific current time values) or with the second trip curve (with (second) specific current time values) a trip, that is to say an avoidance of a current flow (in the low-voltage alternating current circuit to be protected by the circuit breaker) takes place within the trip range.The avoidance of a current flow takes place by opening the contacts of the mechanical break contact unit. Optionally, a current flow (instead of opening the contacts of the mechanical isolation contact unit) can be prevented by a high-resistance state of the semiconductor-based switching elements of the electronic interruption unit (if the latter is provided).The first triggering curve can have, for example, first specific current time values which are close to the current time limit values of the triggering or (approximately) equal to the current time limit values of the triggering. Thus, the circuit breaker triggers in the triggering range only when the standard-dependent required triggering is reached or (shortly before) reached. A high level of supply safety is thus achieved, since short-term overruns in the triggering range do not yet lead to a current-flow-avoiding triggering.The second triggering curve can have, for example, second specific current time values which are close to the current limit values of the non-triggering or (approximately) equal to the current time limit values of the non-triggering. Thus, the protective switching device triggers in the triggering area close to leaving or upon leaving the standard-dependent necessary (safe) guidance of the current flow. A high level of (personal) safety is thus achieved, since already short-term or small exceeds in the triggering range cause a current flow-avoiding triggering.The triggering range cannot be changed on the protective switching device side. Analogous to fault current circuit breakers typically available todayThis has the advantage that the triggering behavior can be selected within a triggering range (a triggering characteristic), i.e. the triggering range is used for a stepped triggering behavior. Graduated adjustment options are adjustable within the standard limits of the standardized triggering range. Thus, the normatively defined triggering range can be used, for example, in order to achieve a more robust or more sensitive triggering behavior.Thus, within the triggering range, the triggering behavior can advantageously be changed in conformity with the standards by a layman.In an advantageous embodiment, this is made possible in particular by an electronic interruption unit in conjunction with a corresponding control unit in the circuit breaker device, whereby a current flow is easily prevented precisely and quickly in terms of time. Thus, without departing from the standard triggering behavior, the triggering behavior can be changed and realized exactly.By standard is meant in particular a manufacturer-specific standard or an EN (European standard) or a DIN standard, i.e. a involuntary standard which is developed under the guidance of the Deutsche Institute for Standardization (DIN) and in which material and intangible objects are unified. DIN standards arise from excitation and by the initiative of interested circles (usually the German Economic), making agreement among all participants.Advantageous embodiments of the invention are specified in the dependent claims.In an advantageous embodiment of the invention, the mechanical isolation contact unit is assigned to the load-side connections. (The optional electronic interrupt unit is assigned in particular to the network-side connection.)This has the particular advantage that an architecture supporting the performance of the circuit breaker device according to the invention is provided, since the control unit and the electronic interruption unit are still supplied with power, independently of the closed or open state of the contacts.In an advantageous embodiment of the invention, the contacts of the mechanical disconnect contact unit can be opened by the control unit, but cannot be closed. This has the particular advantage that a high level of safety of the circuit breaker is provided, since the contacts cannot be closed incorrectly on the inside of the circuit breaker.In an advantageous embodiment of the invention, the mechanical separating contact unit can be operated by a mechanical handle in order to switch opening of the contacts or closing of the contacts.In an advantageous embodiment of the invention, the contacts of the mechanical disconnect contact unit have an enabling functionality. This can be an activation functionality provided according to the standards requirements. In particular, in such a way that the contacts can be opened by the control unit even if the mechanical handle is blocked, i.e. for example if the handle is / is blocked for the closed contact state.This has the particular advantage that high safety and a protective switching device, in particular complying with standards, for low-voltage alternating current circuits are provided. The current flow can be galvanically interrupted at any time by opening the contacts.In an advantageous embodiment of the invention, a third triggering curve (standard) within the triggering range can be selected for the (one) triggering range. Thus, a further triggering behavior within the (one) triggering range can be selected.This has the particular advantage that the triggering behavior can be selected further within the triggering range (a triggering characteristic).That is to say that the triggering range is supplemented by a third triggering curve (with third specific current time values), which can lie between the first and the second triggering curve, for example. A more stepped triggering behavior can thus be achieved.In an advantageous embodiment of the invention, at least one further trigger curve (or further trigger curves) within the trigger range can be selected in an analogous manner for the (one) trigger range. Thus, at least one further (or further) triggering behavior within a triggering range can be selected.This has the particular advantage that the triggering behavior within the triggering range can be selected in a further granular manner, and a higher granularity is achieved.In an advantageous embodiment of the invention, the standard is the standard for residual current / differential current circuit breakers, in particular the standard for residual current / differential current circuit breakers with built-in overcurrent protection (RCBOs) for domestic installations and for similar applications), especially DIN EN 6909 (VDE 0664-20).Alternatively, the standard is a manufacturer-specific standard (for residual current circuit breakers).This has the particular advantage that there are triggering ranges (triggering characteristics) which conform to the standards and which can be further staggered according to the invention, in particular, by layman.In an advantageous embodiment of the invention, the control unit has a microprocessor and a memory. The trigger curves (trigger characteristic curves) are stored in the control unit, in particular in its memory. This has the particular advantage that only a previously stored characteristic curve can be selected as a triggering curve and thus a previously known and checked triggering behavior is achieved. All characteristic curves stored can be checked, for example, during certification (according to standard tests). This ensures that a specific triggering takes place according to the standard (also in the case of different characteristic curves).In an advantageous embodiment of the invention, the protective switching device is designed in such a way that the current flow-preventing triggering takes place by a high-resistance state of the switching elements of the electronic interruption unit, in particular when the contacts of the mechanical disconnection contact unit continue to be closed.This has the particular advantage that a fast and flexible current flow avoidance is provided and the switching times of a mechanical current flow avoidance are avoided.According to the invention, a corresponding method for fault current protection of an electric low-voltage alternating current circuit for alternating voltage, especially for a fault current circuit breaker, is claimed, with the same and further advantages.The method according to the invention for standard-compliant fault current protection for low-voltage alternating current circuits has:an avoidance of a current flow (of the circuit breaker device) is initiated if the level of a fault current is exceeded by specific trigger current time values forming a trigger curve,a standard for residual current / differential current circuit breakers:current time limit values of triggering, so that a current flow in the low-voltage alternating current circuit must be avoided, and current limit values of non-triggering, so that a current flow in the low-voltage alternating current circuit must be conducted, are specified,identifying a triggering area,the specific trigger current time values lie within the trigger range,at least one first triggering curve and one second triggering curve within the triggering range can be selected for the triggering range, so that a different triggering behavior within a triggering range identified as normative can be selected.In an advantageous embodiment of the method, a third triggering curve within the triggering range can be selected for the triggering range.In an advantageous embodiment of the method, the current flow in the protective switching device is prevented by a high-resistance state of switching elements of an electronic interruption unit, in particular in the case of a further closed state of at least one contact of a mechanical isolation contact unit.According to the invention, a corresponding computer program product for a circuit breaker device, in particular a residual current circuit breaker, is claimed. The computer program product comprises instructions which, when the program is executed by a microprocessor, cause the microprocessor to carry out or support the embodiments or methods of the circuit breaker device according to the invention.In particular, if the level of a fault current is exceeded, specific trip current time values forming a trip curve initiate avoidance of a current flow (of the circuit breaker), that at least a first trip curve and a second trip curve can be selected within the trip range for the trip range, so that a different trip behavior can be selected within a trip range identified as normative.According to the invention, a corresponding computer-readable storage medium on which the computer program product is stored is claimed.According to the invention, a corresponding data carrier signal which transmits the computer program product is claimed.All embodiments, both in dependent form referred back to patent claim 1 or 11 and also referred 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, bring about an improvement of a circuit breaker device, in particular of a residual current circuit breaker. In general, a new concept is provided for a circuit breaker, especially a residual current circuit breaker.The described properties, features and advantages of this invention and the manner in which these are achieved become clearer and more clearly comprehensible in conjunction with the following description of the exemplary embodiments, which are explained in more detail in conjunction with the drawing.The drawing shows: FIG. 1 shows a representation with a circuit breaker device, FIG. 2 is a diagram showing a diagram.FIG. 1 shows a representation of a protective switching device SG for protecting an electrical low-voltage alternating current circuit having a housing GEH, having:a housing GEH having 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, in particular:(at least) one network-side phase conductor connection LG,(at least) one load-side phase conductor connection LL for a phase conductor L of the low-voltage alternating current circuit;a neutral conductor connection NG on the mains side,a load-side neutral conductor connection NL for a neutral conductor N of the low-voltage alternating current circuit;a power source is usually connected to the mains-side connections LG, NG / the mains side Grid,a load is usually connected to the load-side connections LL, NL / the load side Load;a mechanical break contact unit MK, which is optionally connected in series with an electronic break unit EU, wherein the electronic break unit EU in the example according to FIG. 1 is configured as a single-pole electronic break unit EU (arranged in the phase conductor L), the second pole (in the neutral conductor N) is (or would) through-connected in this example;the mechanical isolation contact unit (MK) can be switched by a closed state of the contacts for a current flow of the conductors of the low-voltage alternating circuit or an open state of the contacts for a current-flow-preventing galvanic isolation of the conductors of the low-voltage alternating circuit, the (two-pole) mechanical isolation contact unit MK according to FIG. 1 has load-side connection points APLL, APNL and grid-side connection points APLG, APLG, wherein a load-side connection point APNL is provided for the neutral conductor N, a load-side connection point APLL is provided for the phase conductor L, a grid-side connection point APLG is provided for the neutral conductor N, a grid-side connection point APLG is provided for the phase conductor L. The load-side connection points APNL, APLL are connected to the load-side neutral and phase conductor connections NL, LL, wherein the (two-pole) mechanical disconnection contact unit MK has a closed state of a neutral conductor contact KKN (for the neutral conductor) and (at least) one phase conductor contact KKL (for the phase conductor) for a current flow in the low-voltage alternating current circuit or an open state of neutral conductor contact KKN and phase conductor contact KKL for a current-flow-avoiding galvanic disconnection in the low-voltage alternating current circuit, so that an opening of the contacts KKN, KKL for avoiding a current flow or a closing of the contacts KKN, KKL for a current flow in the low-voltage alternating current circuit can be switched,an optional (single-pole) electronic interruption unit EU, which is connected in particular in the phase conductor L in series with the mechanical break contact unit MK, having 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 or is connected with the network-side connection point APLG of the mechanical break contact unit MK, wherein the electronic interruption unit EU has or is switchable by semiconductor-based switching elements (not shown) a high-resistance state of the switching elements in order to avoid a current flow or a low-resistance state of the switching elements in order to flow current in at least one conductor, in particular in the phase conductor L,a differential current sensor unit ZCT for determining the magnitude of a fault current (= differential current) (caused by leakage currents (of the phase conductor L or (and) neutral conductor N to ground or the protective conductor PE)) of the at least two conductors connected to the circuit breaker device, in the example specifically of neutral conductor and phase conductor, of the low-voltage alternating circuit, The differential current sensor unit ZCT is arranged between the electronic interruption unit EU and the mechanical break contact unit MK in the example; it can alternatively be provided (arranged) between the mechanical break contact unit MK and the load-side neutral and phase conductor connections NL, LL, and can also alternatively be provided (arranged) between the electronic interruption unit EU and the grid-side connections NG, LG. The differential current sensor unit ZCT determines the magnitude of the residual current (differential current) of the conductors of the low-voltage alternating current circuit that are routed through the protective switching device (to be protected). In the example, in the case of a single-phase alternating current circuit of neutral conductor N and phase conductor L.The differential current sensor unit ZCT can be a classic sum current converter. The primary side of the sum current converter is formed by the conductors of the low-voltage alternating current circuit (in the example phase conductor L and neutral conductor N). The secondary side of the sum current converter is connected to the control unit SE.a current sensor unit SI for determining the magnitude of the current of the low-voltage alternating current circuit, which is arranged in particular in the phase conductor L (current path of the phase conductor or phase conductor current path), can additionally be provided,a control unit SE which is connected to the differential current sensor unit ZCT, to the (optional) current sensor unit SI, to the mechanical isolation contact unit MK and to the electronic interruption unit EU.The protective switching device is designed in such a way that if the level of the fault current is exceeded, specific trip current time values forming a trip curve initiate avoidance of a current flow. A standard for residual current / differential current circuit breakers is given:current time limit values of the triggering, so that a current flow in the low-voltage alternating current circuit must be avoided, andcurrent limit values of the non-triggering, so that a current flow in the low-voltage alternating current circuit must be carried.The current time limits of the trip and the current limits of the non-trip identify a trip range. The specific trip current time values are within the trip range.The circuit breaker is designed such that at least one first trip curve (Robust) and one second trip curve (Sensitive) within the trip range can be selected for the trip range. Thus, a different triggering behavior within a normatively characterized triggering range can be selected.A third triggering curve (standard) can be selectable for the triggering range within the triggering range, so that a further triggering behavior within the triggering range can be selected.For the triggering range, further triggering curves within the triggering range can be selectable, so that at least one further triggering behavior within the triggering range can be selected.The standard is in particular a standard for residual current / differential current circuit breakers, more particularly a standard for residual current / differential current circuit breakers with built-in overcurrent protection (RCBOs) for domestic installations and for similar applications, especially the standard DIN EN 6909 (VDE 0664-20).The control unit may include a microprocessor and a memory. The trigger curves can then be stored in the control unit, in particular in the memory. The selected trigger curve can be taken from the memory. The values of the selected trigger curve are compared with the determined level of the fault current in the control unit (e.g. with the aid of the microprocessor). If it is exceeded, a current flow-preventing triggering is initiated.The protective switching device can be designed in such a way that the current flow-preventing triggering takes place by a high-resistance state of the switching elements of the electronic interruption unit EU, in particular when the contacts of the mechanical isolation contact unit MK continue to be closed. Alternatively or additionally, the contacts of the mechanical disconnect contact unit MK can also be opened. The triggering behavior for avoiding the current flow can be configurable.In general, a differential current time limit value means a limit value that a differential current (of a specific magnitude-differential current limit value component) must be present for a certain time before the differential current time limit value is exceeded. That is, the differential current time limit value has a differential current limit value component and a time limit value component.In addition, the protective switching device can be designed in such a way that, if current and / or current time limit values are exceeded (i.e. if a (load-side usable) current of a specific level is present in the circuit for a specific time), avoidance of a current flow of the low-voltage alternating current circuit is initiated for one of the levels of the current of the low-voltage alternating current circuit determined by the current sensor unit SI.The mechanical separating contacts unit MK is arranged on the load side in the example, and the electronic interruption unit EU is arranged on the grid side.The grid side Grid with the energy source is normally under electrical voltage. An electrical load is usually connected to the load side Load.This has the advantage that no further parts or components (in particular under voltage) are located between the contacts of the mechanical disconnect contact unit / load-side connection points APLL, APNL of the mechanical disconnect contact unit and the two load-side connections LL, NL. Thus, due to this architecture or construction, it can be ensured that, with the contacts KKL, KKN opened, a voltage is never present at the load-side terminals LL, NL. This increases the safety of the protective switching device / in the low-voltage alternating current circuit. In contrast, in other architectures in which the mechanical isolation contact unit is arranged on the network side, electronic units (not galvanically isolated) are frequently located before the load-side connection.The protective switching device can be designed in such a way that the level of the voltage across the electronic interruption unit EU can be determined. That is to say, the magnitude of a first voltage between grid-side connection point EUGand load-side connection point EULof the electronic interruption unit EU can be ascertained or is ascertained.For this purpose, in the example according to FIG. 1, a first voltage sensor unit SU 1 connected to the control unit SE is provided, which voltage sensor unit 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.During the voltage measurement by the first voltage sensor unit SU 1, alternatively, the voltage across the series circuit of electronic interruption unit EU and current sensor SI can also be determined, as illustrated in FIG. 1. The current sensor unit SI has a very low internal resistance, so that the determination of the magnitude of the voltage is not impaired or is impaired to a negligible extent.Advantageously, a second voltage sensor unit SU 2 can be provided, which determines the level of the voltage between the grid-side neutral conductor terminal NG and the grid-side phase conductor terminal LG.A measurement impedance ZM can be connected between the network-side connection points APLG, APNG of the mechanical isolation contact unit MK. The measurement impedance ZMmay be, for example, an electrical resistor and / or capacitor. The measurement impedance may further be an inductance. In particular, the measurement impedance can be a series circuit or parallel circuit of a resistor and / or capacitor and / or inductance.The electronic interruption unit EU is arranged in the phase conductor L (FIG. 1 ). The grid-side connection point APRG for the neutral conductor of the mechanical isolation contact unit MK is connected to the grid-side neutral conductor connection NG of the housing GEH. According to FIG. 1, this connection is passed through the differential current sensor unit ZCT, for example its sum current converter.The protective switching device SG is advantageously designed in such a way that the contacts KKL, KKN of the mechanical disconnect contact unit MK can be opened by the control unit SE but cannot be closed, which is indicated by an arrow OEF from the control unit SE to the mechanical disconnect contact unit MK.The mechanical disconnect contact unit MK can be operated by a mechanical handle HH on the circuit breaker device SG in order to switch a manual (manual) opening or closing of the contacts KKL, KKN. Both contacts are switched simultaneously, for example. The mechanical handle HH indicates the switching state (open or closed) of the contacts of the mechanical disconnect contact unit MK on the protective switching device. Furthermore, the contact position (or the position of the handle, closed or opened) can be transmitted to the control unit SE. The contact position (or the position of the handle) can be determined, for example, by means of a sensor, such as a position sensor. The contact position or the switching state can be transmitted to the control unit SE. The position sensor may be a part of the mechanical disconnect contact unit MK. For example, a Hall sensor can be provided, which detects and transmits the position of the contacts and / or of the handle without contact.The mechanical disconnect contact unit MK is advantageously designed such that (manual) closing of the contacts by the mechanical handle is possible only after a release (enable), in particular a release signal enable. This is likewise indicated by the arrow from the control unit SE to the mechanical disconnect contacts unit MK. That is to say, the contacts KKL, KKN of the mechanical disconnect contact unit MK can be closed by the handle HH only when the enable or enable signal is present (by the control unit). Without the release or the release signal, the handle HH can be actuated, but the contacts cannot be closed ("permanent slide").The protective switching device SG has a power supply or power supply unit NT, for example a switched-mode power supply. In particular, the power supply / power supply unit NT is provided for the control unit SE, which is indicated by a connection between the power supply / power supply unit NT and the control unit SE in FIG. 1. The power supply / power supply NT is (on the other hand) connected to the grid-side neutral conductor terminal NG and the grid-side phase conductor terminal LG. In the connection to the mains-side neutral conductor connection NG (or / and phase conductor connection LG), a fuse SS, in particular a fuse, or (and) a switch Sch can advantageously be provided.According to the invention, the power supply unit NT is normally constantly supplied with energy, especially from the connections on the power supply unit side. It is optionally protected by the fuse SS or can be switched off by the switch Sch. Advantageously, the switch SCH / Sch can be designed such that the switch can only be opened when the contacts are in the open state. This increases the safety of the device, since the control unit (electronics) cannot be switched off when the contacts are closed.The purpose of the fuse SS is not only to protect the energy supply by means of the power supply unit NT, but is also to protect the "electronic" part or its in particular entire units (such as a special control unit, electronic interruption unit, sum current converter, if necessary, particularly in the case of a two-part construction, for example. Voltage sensor(s), optionally. Current sensor, optionally. Measurement impedance, etc.).The low voltage alternating current circuit may be a three phase alternating current circuit having a neutral conductor and three phase conductors. The protective switching device can be designed as a three-phase variant for this purpose and can have, for example, further line-side and load-side phase conductor connections. Between the further line-side and load-side phase conductor connections, electronic interruption units according to the invention and contacts of the mechanical isolation contact unit are provided in an analogous manner. The respective conductors (three phase conductors L 1, L 2, L 3, neutral conductors N) are routed through the differential current unit ZCT.Current sensor units, voltage determinations (e.g. by first voltage sensor units) can likewise be provided.By high-resistance is meant a state in which only a current of negligible magnitude still flows. In particular, high-resistance values of greater than 1 kiloohm, better greater than 10 kiloohm, 100 kiloohm, 1 megaohm, 10 megaohm, 100 megaohm, 1 gigaohm or greater are meant.By low-ohmic is meant a state in which the current value indicated on the circuit breaker could flow. In particular, low-resistance values are meant which are less than 10 ohms, better less than 1 ohm, 100 milliohms, 10 milliohms, 1 milliohm or less.Mechanical disconnect contact unit MK means, in particular, a (norm-compliant) disconnect function realized by disconnect contact unit MK. With a separation function, the points are:minimum air gap according to standard (minimum distance of the contacts),(mechanical) indication of the contact position of the contacts of the mechanical break contact unit,Triggering or activation functionality, i.e. an actuation for interrupting the contacts of the mechanical disconnect contact unit by the handle or control unit, is always possible, so that no (permanent) blocking of the contacts into the closed state by the handle is possible.In particular, "release" or "enable" functionality means that the contacts can be opened by the control unit even if the mechanical handle (e.g. in the on-state) is blocked.Furthermore, the standardized disconnection function can have the capability of closing the disconnection contact unit or the handle in the switched-on or switched-off state.With regard to the minimum air gap between the contacts of the separating contact unit, this is essentially voltage-dependent. Further parameters are the degree of contamination, the type of field (homogeneous, inhomogeneous), and the air pressure or the height above normal zero.There are corresponding (further) regulations or standards for these minimum air gaps or creepage distances. These (further) regulations specify, for example in the case of air for a surge voltage resistance, the minimum air section for an inhomogeneous and a homogeneous (ideal) electric field as a function of the degree of contamination. The surge voltage strength is the strength when a corresponding surge voltage is applied. Only when this minimum length (minimum distance) is present does the disconnection contact unit or circuit breaker device have a disconnection function (disconnect property).For the purposes of the invention, the series of standards DIN EN 60947 and IEC 60947 can be relevant here in particular for the separator function and its properties.The separating contact unit is advantageously characterized by a minimum air gap of the opened separating contacts in the OFF position (open position, open contacts) as a function of the rated surge voltage resistance and the degree of contamination. The minimum air distance is in particular between (at a minimum) 0.01 mm and 14 mm. In particular, the minimum air gap is advantageously between 0.01 mm at 0.33 kV and 14 mm at 12 kV, in particular for degree of contamination 1 and in particular for inhomogeneous fields.A mechanical break contact unit is in particular not meant to be a relay contact.The circuit breaker can have a (in particular wireless / wireless) communication unit COM which is connected to the control unit SE or is part of it.Furthermore, a display unit AE can be provided. The display unit AE can be configured as a combined display and input unit. The display unit AE (display and input unit) is connected to the control unit SE or a part thereof. The display unit has display means visible on the protective switching device, in particular for displaying the high-impedance or low-impedance state of the electronic interruption unit EU. By means of a combined display and input unit, for example, the first or second (or third / further) trigger curve can be selected.Alternatively or additionally, the first or second (or third / further) trigger curve can be selected, for example, by the communication unit COM.The standard for standard-compliant residual current / differential current protection or its circuit breaker is, for example, the standard for residual current / differential current circuit breakers with built-in excess current protection (RCBOs) for domestic installations and for similar applications, DIN EN 6909 (VDE 0664-20).From the above-mentioned standard, version from 2016 (October), the following Table 2 (section 5.3.8.1-limit values of the switch-off and non-triggering time for alternating currents (effective values) for RCBOs of the type AC and of the type A, page 89) is depicted. Table 2 - Cutoff and non-trip time limits for AC fault currents (effective values) for RCBOs of type AC and type A Table 2 - Cutoff and non-trip time limits for AC fault currents (effective values) for RCBOs of type AC and type ATypeI n AIΔn AIΔn2IΔn5IΔn5IΔn or 0.25 A 35A-200 A, 500 A bIΔtcGenerally, the invention is generally generally practicedAll of them are all complete< 0,030,30,150,040,040,04Maximum Shutdown Time0,030,30,150,040,040,04> 0,030,30,150,040,040,04> 0,030,50,20,150,150,15> 0,030.130.060,050,040,04Minimum Nichlaus O Timea is the value for this test to be specified by the manufacturer.b The tests are carried out only when checking proper operation after 9.9.1.2 d), but in each caseAll values exceeding the instantaneous trip current lower limit are not tested.c. The test is carried out with a current IΔtwhich corresponds to the lower limit value in the range of the instantaneous triggering currentThe Type B corresponds to Type C or Type D, depending on which is applicable. For the tests according to 9.9.1.3 and 9.9.1.4 b)a current IΔt is generated so that the vectorial sum IΔt+I n the lower limit value in the range of the instantaneous valueThe trigger current corresponds to type B, type C or type D, depending on which is more applicable.Further points and explanations can be found in the standard.FIG. 2 shows a diagram on which a current-time behavior is shown. On the horizontal X axis, the leakage current (differential leakage current= AC leakage currents according to the above table) IΔis represented in milliamps [mA], i.e., IΔ / [mA]. This residual current IΔis shown logarithmically in the diagram.On the vertical Y axis, the triggering time t is shown in seconds. The triggering time t (in seconds) is plotted logarithmically in the diagram.In FIG. 2, the diagrams of the above-mentioned elements are shown. Standard (test) points and ranges resulting therefrom: a) the avoidance of a current flow in the low-voltage alternating circuit AUS (current time limit values of triggering), b) the (safe) guidance of a current flow in the low-voltage alternating circuit AIN (current limit values of non-triggering), and the triggering range AB resulting therefrom are entered in a clear manner.The current time limit values of the triggering (region of avoidance of a current flow OFF-right region of FIG. 2 ) are characterized in FIG. 2 by a square (diamond shape) standing on the apex, in the example:First triggering current time limit V 1 (IΔn): 30 mA at 300 ms Second triggering current time limit V 2: 60 mA at 150 ms Third triggering current time limit V 3: 150 mA at 40 ms Fourth triggering current time limit V 4: 250 mA at 40 ms Fifth triggering current time limit V 5: 5A at 40 msThat is to say that in the case of a fault current of or above 30 mA, the fault current circuit breaker or the circuit breaker device according to the invention must avoid (interrupt) the current flow within 300 ms.In the case of a residual current of or above 60 mA, the residual current circuit breaker or the circuit breaker device according to the invention must avoid the current flow within 150 ms.In the case of a residual current of 150 mA (or above), the residual current circuit breaker or the circuit breaker device according to the invention must avoid the current flow within 40 ms.On the other hand, a range of (safe) guidance of a current flow in the low-voltage alternating current circuit ON results which is characterized by the current limit value of the non-triggering IΔno (in the example equal to half the "normal" fault current 1⁄2IΔn) of 15 mA (left-hand region of FIG. 2 ). That is to say that a residual current of up to 15 mA must be able to conduct the residual current circuit breaker or the circuit breaker device according to the invention in an unlimited time without avoiding the current flow (therefore, in the example according to the standard, a current limit value, no current time limit value).This results in a triggering range AB identified by the (test) points, which is identified by way of example by a correspondingly drawn straight line:In the left-hand region (ON) by a vertical straight line, characterized by the current limit value of the non-triggering IΔn(1⁄2IΔn) of 15 mA;In the right-hand region (OFF) by vertical and horizontal straight lines which result from the current-time limit values of the triggering V 1, V 2, V 3 (V 4, V 5).Between the range of non-triggering ON and the range of triggering (range of triggering) OFF, the triggering range AB is located. Triggering usually takes place in this (transition) range between (safe) current conduction and (safe) current avoidance. That is to say that a current can still be conducted here or triggering can take place here, wherein the precise (triggering) (specific) triggering current time limit value is not defined in more detail.It is important that a current is (safely) conducted in the non-triggering region ON (no triggering is effected) and the current is safely avoided in the region of triggering (region of triggering) OFF (a triggering has been effected beforehand). This means that specific trigger current time values are located in the triggering range AB, in which triggering (avoidance of a current flow is initiated) takes place by the protective switching device. These specific trip current time values form a trip curve of the circuit breaker device. By way of example, FIG. 2 shows such a triggering curve, in the example a third triggering curve (standard).According to the invention, it is now proposed that at least one first triggering curve and one second triggering curve can be selected for the triggering range AB within the triggering range AB, so that a different triggering behavior can be selected within the normatively marked triggering range AB.In the example according to FIG. 2, a first triggering curve Robust (close to the range of triggering OFF) and a second triggering curve Sensitive (close to the range of (safe) current conduction ON) are drawn in, which can be selected within the triggering range AB. Thus, a different triggering behavior conforming to the norm can be selected within a triggering range AB identified by normative operation.The first triggering curve Robust is OFF close to the right-hand region of the triggering, so that higher fault currents or fault currents can be carried over a longer time (or higher fault currents can be carried over a longer time). Thus, a triggering takes place only shortly before the region of the (obligatory) triggering OFF.The second triggering curve Sensitive is close to the left-hand region of non-triggering ON, so that even when the region of non-triggering ON is left, low (exceeding) fault currents or the short presence of fault currents can lead to triggering. Thus, a triggering takes place just after leaving the range of non-triggering ON.In FIG. 2, the third triggering curve standard is also provided within the triggering range AB, which is arranged approximately in the middle of the triggering range AB. Thus, a further (or old) triggering behavior within the triggering range can be selected.In an analogous manner, further triggering curves can be provided within the triggering range. Thus, at least one further triggering behavior within the triggering range can be selected.The triggering curves within the triggering range can be selected on or for the circuit breaker by, in particular, a layman. The current flow-avoiding triggering is advantageously effected by an electronic interruption unit EU, thus a triggering and compliance with the selected triggering curve which is accurate over time is possible, which can be realized only more complicatedly with mechanical solutions (mechanical break contact unit).The current flow-avoiding triggering is advantageously effected by a high-impedance state of the switching elements of the electronic interruption unit EU. In particular, in the case of the contacts of the mechanical disconnect contact unit MK still closed.The invention and further aspects are described in other words below. Residual current circuit breakers according to the standard have a trip range, so that present-day devices which meet the same standard can nevertheless have different trip characteristics.The norm produces three ranges. A non-trip area in which the circuit breaker device must safely carry current. A second region of triggering (triggering) in which the current must be reliably interrupted. An intermediate region identifies the so-called triggering region. The trip of the circuit breaker must be within this intermediate range to meet the type standard. However, it is open how the triggering characteristic curve runs in this triggering region / intermediate region.By means of the electronic measurement technology (differential current sensor unit) and the digital algorithm (control unit) of a novel electronic circuit breaker, different triggering characteristic curves can be realized here according to the invention.FIG. 2 shows examples of how a realization could look. The three trigger characteristic lines or operating modes:"Standard", "Sensitive" and "Robust" could be offered and selected on the circuit breaker via a simplified setting possibility.The triggering behavior is defined by a corresponding digital algorithm (e.g. firmware of the control unit in the devices). According to the invention, it is now possible to change the triggering behavior of the circuit breaker device subsequently within existing standard limits.The invention makes possible a simple possibility of changing the triggering behavior without changing the standardized triggering characteristic of the circuit breaker (which was used for the electroplanning of the installation).This thus results in a possibility for setting an electronic circuit breaker which is compliant with existing standards.Since the change in the triggering behavior is realized in such a way that the standardized triggering range (the standardized triggering characteristic) is not changed, this change possibility can itself be made available to laymen in a simplified form.The differential current sensor unit ZCT determines the magnitude of the fault current (differential current) IΔof the (at least) two conductors L, N (connected to the protective switching device) of the low-voltage alternating current circuit, i.e. a fault current IΔ=I L- I N, 3 wherein I L is the magnitude of the phase conductor current (in the phase conductor L), i.e. the magnitude of the current flowing between the grid-side phase conductor connection LG and the load-side phase conductor connection LL, and I N is the magnitude of the neutral conductor current, i.e. the current level of the neutral conductor connection NG on the grid side and the neutral conductor connection NL on the load side flows.In a circuit, the level of the phase conductor current I L( in the circuit breaker) corresponds to the level of the current level of the circuit breaker.Neutral conductor current I N( in the protective switching device), i.e. the magnitude of fault current IΔ=I L- I n is normally equal to zero.The invention can be used in particular in Europe with AC voltages of 230 volts phase conductor to neutral conductor or 400 volts between two phase conductors (not shown), effective values of the AC voltage.The neutral conductor is usually grounded on the energy source side. The ground-side neutral conductor terminal is usually provided as a protective conductor terminal PE (Protective Earth).Although the invention has been illustrated and described in more detail by the exemplary embodiment, the invention is not restricted by the disclosed examples and other variations can be derived therefrom by the person skilled in the art without departing from the scope of protection of the invention.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2013 219 292 A1

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[0005] Cited Non-Patent LiteratureDIN EN 6909 (VDE 0664-20 [0044, 0103]

Claims

Protective switching device for standard-compliant fault current protection for low-voltage alternating current circuits, having: - a housing (GEH) having 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 disconnection contact unit (MK) which can be switched by a closed state of the contacts for a current flow of the conductors of the low-voltage alternating current circuit or an open state of the contacts for a current-flow-avoiding galvanic disconnection of the conductors of the low-voltage alternating current circuit, - a differential current sensor unit (ZCT) for determining the level of a fault current of the at least two conductors of the low-voltage alternating current circuit connected to the protective switching device, - a control unit (SE), which is connected to the differential current sensor unit (ZCT) and to the mechanical break contact unit (MK), wherein, if the level of the fault current is exceeded, specific trip current time values forming a trip curve are initiated, an avoidance of a current flow, - that a standard for fault current / differential current circuit breakers specifies: a) current time limit values of the trip, so that a current flow in the low-voltage alternating current circuit must be avoided, and b) current limit values of the non-trip, so that a current flow in the low-voltage alternating current circuit must be conducted, which indicate a trip range (AB), - that the specific trip current time values are within the trip range (AB), - that the protective switching device is designed in such a way that, at least one first triggering curve (Robust) and one second triggering curve (Sensitive) within the triggering range (AB) can be selected for the triggering range (AB), so that a different triggering behavior within a triggering range (AB) identified as normative can be selected.Protective switching device (SG) according to Patent Claim 1, characterized in that the mechanical disconnection contact unit (MK) is connected in series with an electronic disconnection unit (EU), in that the electronic disconnection unit (EU) can be switched by semiconductor-based switching elements into a high-resistance state of the switching elements in order to avoid a current flow of at least one conductor or a low-resistance state of the switching elements in order to avoid a current flow in the low-voltage alternating current circuit, in that the control unit (SE) is connected to the electronic disconnection unit (EU), in that the protective switching device is designed in such a way that the current-flow-avoiding triggering takes place by a high-resistance state of the switching elements of the electronic disconnection unit (EU), in particular when the state of the contacts of the mechanical disconnection contact unit (MK) continues to be closed.Circuit breaker device (SG) according to Patent Claim 1 or 2, characterized in that the mechanical disconnection contact unit (MK) is assigned to the load-side connection.Circuit breaker device (SG) according to one of the preceding patent claims, characterized in that the contacts of the mechanical disconnection contact unit (MK) can be opened but cannot be closed by the control unit (SE).Circuit breaker device (SG) according to one of the preceding patent claims, characterized in that the mechanical disconnection contact unit (MK) can be operated by a mechanical handle (HH) in order to switch opening of the contacts or closing of the contacts.Circuit breaker device (SG) according to Patent Claim 5, characterized in that the contacts of the mechanical disconnection contact unit (MK) have an activation functionality in such a way that the contacts are opened by the control unit (SE), even if the mechanical handle (HH) is blocked.Circuit breaker device (SG) according to one of the preceding patent claims, characterized in that a third trip curve (standard) can be selected within the trip range for the trip range, such that a further trip behavior can be selected within the trip range.Circuit breaker device (SG) according to one of the preceding patent claims, characterized in that at least one further trip curve can be selected within the trip range for the trip range, such that at least one further trip behavior can be selected within the trip range.Circuit breaker device (SG) according to one of the preceding patent claims, characterized in that the standard is the standard for residual current / differential current circuit breakers, in particular the standard for residual current / differential current circuit breakers with integrated overcurrent protection, especially DIN EN 61009-1 or 61008-1 (VDE 0664-20).Circuit breaker (SG) according to one of the preceding patent claims, characterized in that the control unit has a microprocessor and a memory, and in that the triggering curves are stored in the control unit.Method for a protective switching device for standard-compliant fault current protection for low-voltage alternating circuits, - that if the level of a fault current is exceeded, specific trip current time values forming a trip curve are initiated, an avoidance of a current flow, - that a standard for fault current / differential current circuit breakers a) specifies current time limit values of the trip, so that a current flow in the low-voltage alternating circuit must be avoided, and b) specifies current limit values of the non-trip, so that a current flow in the low-voltage alternating circuit must be conducted, which identify a trip range, - that the specific trip current time values are within the trip range, - that at least one first trip curve (Robust) and one second trip curve (Sensitive) within the trip range can be selected for the trip range, such that a different triggering behavior can be selected within a triggering range identified as normative.Method according to claim 11, characterised in that a third triggering curve (standard) within the triggering range can be selected for the triggering range.Method according to claim 11 or 12, characterised in that the current flow in the protective switching device is prevented by a high-resistance state of switching elements of an electronic interruption unit (EU), in particular in the case of a further closed state of at least one contact of a mechanical isolation contact unit (MK).

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