Circuit breaker device and method

Abstract

The invention relates to a circuit breaker device for a low-voltage AC circuit fault-current protection function which complies with standards, wherein - when the level of a fault current exceeds specific trigger current time values, which form a trigger curve, a process of preventing a current flow is initiated, - a standard for fault current / differential current circuit breakers specifies a) current time limit values for the triggering process (AUS), so that a current flow is to be prevented in the low-voltage AC circuit, and b) current limit values for the non-triggering process (EIN), so that a current flow is to be conducted in the low-voltage AC circuit, said limit values characterizing a trigger range (AB) - the specific trigger current time values lie within the trigger range, and - for the trigger range, at least one first trigger curve (robust) and a second trigger curve (sensitive) can be selected within the trigger range so that a different trigger behavior can be selected within a standard characterized trigger range.

Description

[0001] Description

[0002] Protective switching device and procedure

[0003] The invention relates to the technical field of a protective switching device for standard-compliant residual current protection for protecting an electrical low-voltage alternating current circuit and a method for a protective switching device for standard-compliant residual current protection of an electrical low-voltage alternating current circuit.

[0004] The term "protective switching device" refers to low-voltage protective switching devices, particularly residual current circuit breakers. Low voltage refers to voltages up to 1000 volts AC or 1500 volts DC. Low voltage refers specifically to voltages higher than extra-low voltage, with values ​​of 50 volts AC or 120 volts DC.

[0005] Low-voltage circuits refer to circuits for currents up to 6300 amps, more specifically 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 refer in particular to rated currents (formerly nominal and / or breaking currents), i.e., currents that the circuit or a protective switching device can carry continuously, i.e., without damage, under standardized conditions (such as the cross-sections of the copper conductors and their lengths) at a defined ambient temperature (such as 40°C). Such points are defined in relevant product standards (e.g., DIN EN 60947-2 or 60898-1 as well as 61008-1 or 61009-1). This means, colloquially, the maximum current that is normally carried through the circuit.where the electrical circuit is usually interrupted, for example, by a protective switching device such as a miniature circuit breaker or a circuit breaker. Residual current circuit breakers are used primarily for rated current ranges of or up to 6, 10, 16, 25, 32, 40, 63, 80, or 125 amperes.

[0006] Residual current circuit breakers for electrical circuits, particularly for low-voltage AC circuits or systems, are well known. Residual current circuit breakers are also referred to as residual current devices (RCDs). State-of-the-art residual current circuit breakers are known from the following patent applications: DE 10 2013 219 292 A1; DE 10 2015 224 890 A1; DE 10 2015 225

[0007] 423 Al; DE 10 2015 225 910 Al; DE 10 2015 218 911 Al; EN 10

[0008] 2015 215 456 Al; DE 10 2016 213 875 Al; DE 10 2016 205 101 Al; DE 10 2017 217 040 Al; DE 10 2017 217 267 Al; DE 10 2017

[0009] 217 411 To; FROM 10 2018 200 714 To.

[0010] Residual current circuit breakers measure the current sum (i.e. a total current or, depending on the current / power flow direction, a differential current) between two or more conductors in an electrical circuit, which is normally zero, and interrupt the electrical circuit when a residual current or differential current value is exceeded, i.e. a current sum not equal to zero that exceeds a certain differential current limit value (differential current threshold value or response current value or residual current value or fault response current value), which is also referred to as tripping. To be more precise, these residual current or differential current values ​​are residual current time (limit) values ​​or differential current time (limit) values, i.e. a residual current or differential current value that exceeds a certain level must also be present for a certain time.Typical residual current thresholds are, for example, 30 mA for personal protection and 300 mA for fire protection (IEC world, 230 volt / 400 volt nominal voltage network). For special personal protection requirements, a residual current threshold of 10 mA or 6 mA is typical. Almost all current circuit breakers to date have a summation current transformer, whose primary windings are formed by the conductors of the circuit and whose secondary winding delivers the current sum or the residual current or an equivalent of the current sum / the differential current, e.g., in the form of a voltage (or current), which is used directly or indirectly to interrupt the electrical circuit.

[0011] For this purpose, two or more conductors, usually the forward and return conductors or the phase conductor (= outer conductor) and neutral conductor in a single-phase alternating current system, all three phase conductors (= outer conductor) or all three phase conductors (= outer conductor) and the neutral conductor in a three-phase alternating current system, are passed through a current transformer, usually with a ring-shaped core made of ferromagnetic material. Only the differential current from the conductors, i.e. a current that differs from the forward and return current, is converted (or transferred to the secondary winding). The total current in an electrical circuit is usually zero. This allows fault currents to be detected.

[0012] For example, if a current flows to earth on the energy sink or load side, this is referred to as a fault current. This is the case, for example, when a person touches a live phase conductor. In this case, this current to earth is referred to as a fault current.

[0013] In contrast, electrical equipment (such as power supplies or frequency converters) can also discharge a current to ground due to, for example, so-called Y capacitors. This current is typically referred to as leakage current.

[0014] A fault occurs, for example, when there is an electrically conductive connection from a phase conductor or outer conductor of the electrical circuit to earth. For example, when a person touches the phase conductor. In this case, part of the electrical current does not flow back via the neutral conductor as usual, but via the person and the earth. This fault current can now be detected with the help of the summation current transformer, since the recorded sum of the incoming and returning current is not equal to zero. An interruption of the electrical circuit, e.g. at least one, some or all of the lines, is brought about via a holding magnet release (= self-holding magnet) or a relay or a trip coil, generally an interruption unit, for example with connected mechanics and contacts.

[0015] The main function of residual current circuit breakers is to protect people from electrical currents (electric shock), as well as systems, machines or buildings from fire caused by electrical insulation faults.

[0016] If the residual current device or its summation current transformer is designed in such a way that the secondary-side energy is sufficient to actuate a tripping unit or an interruption unit or a release, then such residual current devices are said to be mains voltage independent; otherwise they are said to be mains voltage dependent.

[0017] If a power supply is intended to supply power to a residual current detection system, it is a line-voltage-dependent residual current device. These are required, for example, to detect residual currents in DC voltage networks and mixed DC / AC networks, or in high-frequency circuits.

[0018] Residual current circuit breakers are available in different versions, referred to as types, and are identified by letters or letter combinations, such as AC, A, F, G, K, S, B, B+. Each type detects a specific type of residual current. Currently, residual current circuit breakers are available in 2-pole versions for phase and neutral conductors (L+N), 3-pole versions for three phase conductors (LI, L2, L3), and 4-pole versions for three phase conductors and neutral conductors (LI, L2, L3, N).

[0019] For example, type AC only detects purely sinusoidal fault currents. Type A detects both purely sinusoidal alternating currents and pulsating direct residual currents. Type F are mixed-frequency sensitive residual current devices. They detect all types of fault current like type A, but are also suitable for detecting fault currents consisting of a mixture of frequencies up to 1 kHz. Type S are selective residual current circuit breakers which can be graded in terms of both the rated residual current and the tripping time. Type B residual current circuit breakers (= residual current protective devices) are used to detect not only type F fault current waveforms but also smooth direct residual currents. They are also suitable for fault currents with frequencies up to 2 kHz. The same conditions apply to type B+ residual current circuit breakers as to type B residual current circuit breakers.Only the frequency range for detecting residual currents is extended to 20 kHz. Type K residual current circuit breakers have the characteristics of Type A, but their tripping behavior is delayed slightly. Type K circuit breakers are also referred to as super-resistant.

[0020] The product standards DIN EN 61008-1 (residual current circuit breaker) and DIN EN 61009-1 (residual current / loop control switch) describe the behavior of residual current circuit breakers, in particular the limit values ​​for the switching-off times.

[0021] Protective switching devices with an electronic interruption unit are relatively new developments. They have a semiconductor-based electronic interruption unit. This means that the electrical current flow in the low-voltage alternating current circuit is conducted via semiconductor components or semiconductor switches, which interrupt the electrical current flow or can be made conductive. Protective switching devices with an electronic interruption unit also often have a mechanical isolating contact system, in particular with isolating properties in accordance with the relevant standards for low-voltage alternating current circuits. The contacts of the mechanical isolating contact system are connected in series to the electronic interruption unit, this means that the current in the low-voltage alternating current circuit to be protected is conducted both (at least partially) via the mechanical isolating contact system and via the electronic interruption unit.

[0022] The object of the present invention is to improve a protective switching device, in particular a residual current circuit breaker. Specifically, to achieve greater flexibility with regard to the tripping behavior.

[0023] This object is achieved by a protective switching device having the features of patent claim 1 and a method having the features of patent claim 11.

[0024] According to the invention, a protective switching device, in particular a residual current circuit breaker, for protecting an electrical low-voltage alternating current circuit for alternating voltage is proposed, comprising:

[0025] - a housing with at least two mains-side and at least two load-side connections for at least two conductors of the low-voltage alternating current circuit, for connecting at least two conductors of the low-voltage alternating current circuit, in particular a phase conductor and a neutral conductor of the low-voltage alternating current circuit (alternatively for two phase conductors of the low-voltage alternating current circuit; phase conductors (and a neutral conductor)),

[0026] - a differential current sensor unit for determining the level of a fault current (differential current) of at least two conductors (connected to the protective switching device) of the low-voltage alternating current circuit (i.e., for example, the differential current of the phase conductor and neutral conductor (alternatively, the differential current of two phase conductors)),

[0027] - a mechanical isolating contact unit, which is in particular (optionally) connected in series with an electronic interruption unit, (wherein the series connection is connected on the one hand to at least one of the mains-side terminals and on the other hand to at least one of the load-side terminals,)

[0028] - that the mechanical isolating 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-preventing galvanic separation of the conductors of the low-voltage alternating current circuit,

[0029] (i.e., phase conductor and neutral conductor or both phase conductors, phase conductors (and neutral conductor))

[0030] - that the optional electronic interruption unit can be switched by semiconductor-based switching elements into a high-resistance state of the switching elements to prevent a current flow of at least one conductor (for example the phase conductor) or a low-resistance state of the switching elements to allow current flow in the low-voltage AC circuit,

[0031] - a control unit connected to the differential current sensor unit, the mechanical isolating contact unit and optionally the electronic interruption unit, whereby if the level of the fault current is exceeded, the avoidance of a current flow is initiated via specific tripping current time values ​​forming a tripping curve,

[0032] - that a standard for residual current / differential current circuit breakers specifies a) tripping current-time limits, so that a current flow in the low-voltage alternating current circuit must be avoided, and b) non-tripping current limits, so that a current flow in the low-voltage alternating current circuit must be maintained, which characterise a tripping range, - that the specific tripping current-time values ​​lie within the tripping range,

[0033] - that the protective switching device is designed in such a way that at least one first tripping curve and one second tripping curve can be selected for the tripping range, so that a different tripping behavior can be selected within a normatively identified tripping range.

[0034] This means that the protective switching device has two tripping curves, so that either the first tripping curve (with (first) specific current-time values) or the second tripping curve (with (second) specific current-time values) triggers a trip, i.e. a current flow is avoided (in the low-voltage AC circuit to be protected by the protective switching device), within the tripping range.

[0035] Current flow is prevented by opening the contacts of the mechanical isolating contact unit. Optionally, current flow can be prevented (instead of opening the contacts of the mechanical isolating contact unit) by a high-impedance state of the semiconductor-based switching elements of the electronic interruption unit (if the latter is provided).

[0036] The first tripping curve can, for example, have initial specific current-time values ​​that are close to the current-time limit values ​​for tripping or are (approximately) equal to the current-time limit values ​​for tripping. Thus, the protective switching device in the tripping range only trips when the required tripping is almost reached or (just before) the standard-based tripping is reached. This achieves a high level of supply reliability, since brief exceedances within the tripping range do not yet lead to a current-preventing trip.

[0037] The second tripping curve can, for example, have two specific current-time values ​​that are close to the non-tripping current limits or (approximately) equal to the non-tripping current-time limits. Thus, the protective switching device trips in the tripping range shortly after leaving or upon leaving the standard-required (safe) current flow guidance. This achieves a high level of (personnel) safety, since even brief or minor exceedances of the tripping range cause tripping to prevent current flow.

[0038] The tripping range cannot be changed on the circuit breaker side. Similar to typical residual current devices available today

[0039] This 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 graduated triggering behavior. Graduated setting options can be set within the standard limits of the standardized triggering range. Thus, the normatively defined triggering range can be used, for example, to achieve a more robust or more sensitive triggering behavior.

[0040] This means that the triggering behavior can be changed by a layperson in accordance with the standards within the triggering range.

[0041] In an advantageous embodiment, this is made possible, in particular, by an electronic interruption unit in conjunction with a corresponding control unit in the protective switching device, which allows for a precise and rapid prevention of current flow. This allows the tripping behavior to be modified and precisely implemented without deviating from the standard tripping behavior.

[0042] A standard refers in particular to a manufacturer-specific standard, an EN (European standard), or a DIN standard, i.e., a voluntary standard developed under the direction of the German Institute for Standardization (DIN), in which tangible and intangible objects are standardized. DIN standards are created at the suggestion and through the initiative of interested parties (usually German industry), whereby consensus is achieved among all parties involved. Advantageous embodiments of the invention are specified in the subclaims.

[0043] In an advantageous embodiment of the invention, the mechanical isolating contact unit is assigned to the load-side connections. (The optional electronic interruption unit is assigned, in particular, to the mains-side connection.) This has the particular advantage of providing an architecture that supports the inventive behavior of the protective switching device, since the control unit and the electronic interruption unit continue to be supplied with energy, regardless of the closed or open state of the contacts.

[0044] In an advantageous embodiment of the invention, the contacts of the mechanical isolating contact unit can be opened by the control unit, but cannot be closed. This has the particular advantage of ensuring a high level of safety for the protective switching device, since the contacts cannot be incorrectly closed within the protective switching device.

[0045] In an advantageous embodiment of the invention, the mechanical isolating contact unit can be operated by a mechanical handle in order to switch the contacts to open or close.

[0046] In an advantageous embodiment of the invention, the contacts of the mechanical isolating contact unit have an enabling function. This can be an enabling function provided for in accordance with the relevant standards. In particular, such 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.

[0047] This has the particular advantage of providing a high level of safety and a protective switching device that complies with standards for low-voltage AC circuits. The current flow can be galvanically interrupted at any time by opening the contacts.

[0048] In an advantageous embodiment of the invention, a third trigger curve (standard) can be selected within the trigger range. This allows a further triggering behavior to be selected within the trigger range.

[0049] This has the particular advantage that the triggering behavior can be further selected within the triggering range (a triggering characteristic).

[0050] This means that the tripping range is supplemented by a third tripping curve (with third specific current-time values), which can, for example, be located between the first and second tripping curves. This allows for a more graduated tripping behavior.

[0051] In an advantageous embodiment of the invention, at least one further triggering curve (or further triggering curves) can be selected within the triggering range in an analogous manner for the (one) triggering range. Thus, at least one further triggering behavior (or behaviors) can be selected within a triggering range.

[0052] This has the particular advantage that the triggering behavior can be selected more granularly within the triggering range, thus achieving a higher granularity.

[0053] 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), specifically DIN EN 61009 (VDE 0664-20).

[0054] Alternatively, the standard is a manufacturer-specific standard (for residual current circuit breakers).

[0055] This has the particular advantage that standard-compliant triggering ranges (triggering characteristics) are available, which according to the invention can be further graded in a way that is particularly easy to operate by laypersons.

[0056] In an advantageous embodiment of the invention, the control unit has a microprocessor and a memory. The tripping curves (tripping characteristics) 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 the tripping curve, thus achieving a previously known and tested tripping behavior. All stored characteristic curves can, for example, be tested during certification (according to standard tests). This ensures that a specific tripping occurs according to the standard (even with different characteristic curves).

[0057] In an advantageous embodiment of the invention, the protective switching device is designed in such a way that the current flow-preventing tripping occurs through a high-impedance state of the switching elements of the electronic interruption unit, in particular when the contacts of the mechanical isolating contact unit continue to be closed.

[0058] 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.

[0059] According to the invention, a corresponding method for residual current protection of an electrical low-voltage alternating current circuit for alternating voltage, especially for a residual current circuit breaker, with the same and further advantages is claimed.

[0060] The inventive method for standard-compliant residual current protection for low-voltage AC circuits comprises:

[0061] -that if the magnitude of a fault current is exceeded, the prevention of a current flow (of the protective switching device) is initiated via a tripping curve forming specific tripping current-time values, - that a standard for residual current / differential current protective switches:

[0062] current-time limit values ​​for tripping, so that a current flow in the low-voltage alternating current circuit must be avoided, and current limit values ​​for non-tripping, so that a current flow in the low-voltage alternating current circuit must be maintained, which characterise a tripping range, -that the specific tripping current-time values ​​lie within the tripping range,

[0063] - that at least one first triggering curve and one second triggering curve can be selected within the triggering range, so that a different triggering behavior can be selected within a normatively designated triggering range.

[0064] In an advantageous embodiment of the method, a third triggering curve can be selected within the triggering range.

[0065] In an advantageous embodiment of the method, the current flow in the protective switching device is avoided by a high-resistance state of switching elements of an electronic interruption unit, in particular when at least one contact of a mechanical isolating contact unit remains closed.

[0066] According to the invention, a corresponding computer program product for a protective switching 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 implement or support the inventive embodiments or methods of the protective switching device.

[0067] In particular, that when the level of a fault current is exceeded, an avoidance of a current flow (of the protective switching device) is initiated via concrete tripping current-time values ​​forming a tripping curve, that for the tripping range at least a first tripping curve and a second tripping curve can be selected within the tripping range, so that a different tripping behavior can be selected within a normatively identified tripping range.

[0068] According to the invention, a corresponding computer-readable storage medium on which the computer program product is stored is claimed.

[0069] According to the invention, a corresponding data carrier signal which transmits the computer program product is claimed.

[0070] All embodiments, both in dependent form referring back to patent claim 1 or 11, and 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, result in an improvement of a protective switching device, in particular a residual current circuit breaker. In general, a new concept for a protective switching device, specifically a residual current circuit breaker, is provided.

[0071] The described properties, features and advantages of this invention as well as the manner in which these are achieved will become clearer and more clearly understandable in connection with the following description of the embodiments, which are explained in more detail in connection with the drawing.

[0072] The drawing shows:

[0073] Figure 1 shows a diagram with a protective switching device,

[0074] Figure 2 is a representation of a diagram.

[0075] Figure 1 shows a representation of a protective switching device SG for protecting an electrical low-voltage alternating current circuit with a housing GEH, comprising: - a housing 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, in particular:

[0076] - (at least) one mains-side phase conductor connection LG,

[0077] - (at least ) one load-side phase conductor connection LL, for one phase conductor L of the low-voltage alternating current circuit ;

[0078] - a mains-side neutral conductor connection NG,

[0079] - a load-side neutral conductor connection NL, for a neutral conductor N of the low-voltage alternating current circuit;

[0080] - an energy source is usually connected to the grid-side connections LG, NG / the grid side,

[0081] - a consumer is usually connected to the load-side connections LL, NL / the load side Load;

[0082] - a mechanical isolating contact unit MK, which is optionally connected in series with an electronic interruption unit EU, the electronic interruption unit EU in the example according to Figure 1 being designed as a single-pole (arranged in the phase conductor L) electronic interruption unit EU, the second pole (in the neutral conductor N) is (or would be) connected through in this example;

[0083] - that the mechanical isolating contact unit (MK) can be switched by a closed state of the contacts for a current flow in 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, the (two-pole) mechanical isolating contact unit MK according to Figure 1 has load-side connection points APLL, APNL and mains-side connection points APLG, APNG, whereby 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 mains-side connection point APNG is provided for the neutral conductor N, and a mains-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, whereby the (two-pole) mechanical isolating 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 AC circuit or an open state of neutral conductor contact KKN and phase conductor contact KKL for a current flow-preventing galvanic isolation in the low-voltage AC circuit, so that an opening of the contacts KKN, KKL to prevent a current flow or a closing of the contacts KKN, KKL for a current flow in the low-voltage AC circuit can be switched.

[0084] - an optional (single-pole) electronic interruption unit EU, which is connected in series with the mechanical isolating contact unit MK, in particular in the phase conductor L, with a mains-side connection point EUG, which is electrically connected to the mains-side phase conductor connection LG, and a load-side connection point EUL, which is electrically connected or connected to the mains-side connection point APLG of the mechanical isolating contact unit MK, wherein the electronic interruption unit EU has or can be switched to a high-resistance state of the switching elements to prevent a current flow or a low-resistance state of the switching elements for current flow in at least one conductor, in particular in the phase conductor L, by means of semiconductor-based switching elements (not shown),

[0085] - a differential current sensor unit ZCT, for determining the level of a fault current (= differential current) (caused by leakage currents (of the phase conductor L or (and) neutral conductor N against earth or the protective conductor PE)) of at least two conductors connected to the protective switching device, in the example specifically the neutral conductor and phase conductor, of the low-voltage alternating current circuit, the differential current sensor unit ZCT is arranged in the example between the electronic interruption unit EU and the mechanical isolating contact unit MK, it can alternatively be provided (arranged) between the mechanical isolating contact unit MK and the load-side neutral and phase conductor connections NL, LL, and alternatively be provided (arranged) between the electronic interruption unit EU and the mains-side connections NG, LG.The ZCT differential current sensor unit determines the magnitude of the fault current (differential current) of the conductors of the low-voltage alternating current circuit routed through the protective switching device (to be protected). In the example, for a single-phase alternating current circuit, this is the neutral conductor N and the phase conductor L.

[0086] The ZCT differential current sensor unit can be a conventional summation current transformer. The primary side of the summation current transformer is formed by the conductors of the low-voltage AC circuit (in the example, phase conductor L and neutral conductor N).

[0087] The secondary side of the summation current transformer is connected to the control unit SE.

[0088] - in addition, a current sensor unit SI can be provided to determine the level 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),

[0089] - a control unit SE which is connected to the differential current sensor unit ZCT, to the (optional) current sensor unit SI, to the mechanical isolating contact unit MK and to the electronic interruption unit EU.

[0090] The protective device is designed in such a way that, if the magnitude of the fault current is exceeded, a current flow prevention is initiated via a tripping curve forming specific tripping current-time values. A standard for residual current / differential current protective devices specifies:

[0091] - current-time tripping limits, so that current flow in the low-voltage AC circuit must be avoided, and

[0092] - Non-tripping current limits, which require a current flow in the low-voltage AC circuit. The tripping current-time limits and the non-tripping current limits define a tripping range. The actual tripping current-time values ​​lie within the tripping range.

[0093] The protective switching device is designed such that at least one first tripping curve (Robust) and one second tripping curve (Sensitive) can be selected within the tripping range. This advantageously allows different tripping behaviors to be selected within a normatively designated tripping range.

[0094] For the trigger range, a third trigger curve (standard) can be selected within the trigger range, so that a further trigger behavior can be selected within the trigger range.

[0095] For the triggering range, further triggering curves can be selected within the triggering range, so that at least one further triggering behavior can be selected within the triggering range.

[0096] The standard is in particular a standard for residual current / differential current circuit breakers, more specifically a standard for residual current / differential current circuit breakers with built-in overcurrent protection (RCBOs) for domestic installations and for similar applications, specifically the standard DIN EN 61009 (VDE 0664-20).

[0097] The control unit can have a microprocessor and a memory. The tripping curves can then be stored in the control unit, particularly in the memory. The selected tripping curve can be taken from the memory. The values ​​of the selected tripping curve are compared with the determined level of the fault current in the control unit (e.g., with the help of the microprocessor). If this value is exceeded, a current-preventing trip is initiated.

[0098] The protective switching device can be designed such that the current-preventing tripping occurs when the switching elements of the electronic interruption unit EU are in a high-impedance state, particularly when the contacts of the mechanical isolating contact unit MK remain closed. Alternatively or additionally, the contacts of the mechanical isolating contact unit MK can also be opened. The tripping behavior to prevent current flow can be configurable.

[0099] In general, a residual current time limit refers to a limit value that requires a residual current (of a certain magnitude – residual current limit component) to be present for a certain period of time before the residual current time limit is exceeded. This means that the residual current time limit has a residual current limit component and a time limit component.

[0100] 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 useful) current of a certain level is present in the circuit for a certain time) for one of the levels of the current of the low-voltage alternating current circuit determined by the current sensor unit SI, an avoidance of a current flow in the low-voltage alternating current circuit is initiated.

[0101] In the example, the mechanical isolating contact unit MK is arranged on the load side, the electronic interruption unit EU is arranged on the mains side.

[0102] The grid side, containing the energy source, is normally live. An electrical consumer is usually connected to the load side.

[0103] This has the advantage that there are no other (particularly live) parts or components between the contacts of the mechanical isolating contact unit / load-side connection points APLL, APNL of the mechanical isolating contact unit and the two load-side connections LL, NL. This architecture and design ensures that when contacts KKL, KKN are open, there is never any voltage at the load-side connections LL, NL. This increases the safety of the protective switching device in the low-voltage AC circuit. In contrast, in other architectures where the mechanical isolating contact unit is arranged on the mains side, there are often (non-galvanically isolated) electronic units upstream of the load-side connection.

[0104] The protective switching device can be designed such that the voltage level across the electronic interruption unit EU can be determined. This means that the level of a first voltage between the mains-side connection point EUG and the load-side connection point EUL of the electronic interruption unit EU can be determined or is determined.

[0105] For this purpose, in the example according to Figure 1, a first voltage sensor unit SUI is provided which is connected to the control unit SE and which determines the level of the voltage between the network-side connection point EUG and the load-side connection point EUL of the electronic interruption unit EU.

[0106] When measuring the voltage by the first voltage sensor unit SUI, the voltage across the series circuit of the electronic interruption unit EU and the current sensor SI can alternatively be determined, as shown in Figure 1. The current sensor unit SI has a very low internal resistance, so that the determination of the voltage level is not affected or is negligibly affected.

[0107] Advantageously, a second voltage sensor unit SU2 can be provided which determines the level of the voltage between the mains-side neutral conductor connection NG and the mains-side phase conductor connection LG.

[0108] A measuring impedance ZM can be connected between the mains-side connection points APLG, APNG of the mechanical isolating contact unit MK. The measuring impedance ZM can, for example, be an electrical resistor and / or capacitor. The measuring impedance can also be an inductance. In particular, the measuring impedance can be a series or parallel connection of a resistor and / or capacitor and / or inductance.

[0109] The electronic interruption unit EU is located in the phase conductor L (Figure 1). The mains-side connection point APNG for the neutral conductor of the mechanical isolating contact unit MK is connected to the mains-side neutral conductor connection NG of the housing GEH. This connection is made, as shown in Figure 1, through the differential current sensor unit ZCT, for example, its summation current transformer.

[0110] The protective switching device SG is advantageously designed in such a way that the contacts KKL, KKN of the mechanical isolating contact unit MK can be opened but not closed by the control unit SE, which is indicated by an arrow OEF from the control unit SE to the mechanical isolating contact unit MK.

[0111] The mechanical isolating contact unit MK can be operated using a mechanical handle HH on the protective switch device SG in order to manually open or close 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 isolating contact unit MK on the protective switch device. Furthermore, the contact position (or the position of the handle, closed or open) can be transmitted to the control unit SE. The contact position (or the position of the handle) can, for example, be determined using 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 can be part of the mechanical isolating contact unit MK. E.g.A Hall sensor can be provided which detects and transmits the position of the contacts and / or the handle without contact. The mechanical isolating contact unit MK is advantageously designed in such a way that (manual) closing of the contacts by the mechanical handle is only possible after an enable signal, in particular an enable signal. This is also indicated by the arrow from the control unit SE to the mechanical isolating contact unit MK. This means that the contacts KKL, KKN of the mechanical isolating contact unit MK can only be closed by the handle HH when the enable signal or the enable signal is present (from the control unit). Without the enable signal or the enable signal, the handle HH can be actuated, but the contacts cannot be closed ("continuous slipping").

[0112] The protective switching device SG has a power supply or power supply NT, for example a switched-mode power supply. In particular, the power supply / power supply NT is provided for the control unit SE, which is indicated by a connection between the power supply / power supply NT and the control unit SE in Figure 1. The power supply / power supply NT is (on the other hand) connected to the mains-side neutral conductor connection NG and the mains-side phase conductor connection LG. A fuse SS, in particular a melting fuse, or (and) a switch Sch can advantageously be provided in the connection to the mains-side neutral conductor connection NG (and / or phase conductor connection LG).

[0113] According to the invention, the NT power supply is normally continuously supplied with power, specifically from the mains-side connections. It is protected by the SS fuse if necessary or can be switched off using the Sch switch.

[0114] Advantageously, the SCH / Sch switch can be designed so that it can only be opened when the contacts are in the open state. This increases the safety of the device, as the control unit (electronics) cannot be switched off when the contacts are closed.

[0115] The purpose of the SS fuse is not only to protect the energy supply via the NT power supply unit, but is also intended to protect the "electronic" part or its entire units (such as the control unit, electronic interruption unit, summation current transformer, if applicable, voltage sensor(s), if applicable, current sensor, if applicable, measuring impedance, etc.), particularly in the case of a two-part structure.

[0116] The low-voltage AC circuit can be a three-phase AC circuit with a neutral conductor and three phase conductors. The protective switching device can be designed as a three-phase variant for this purpose and, for example, have additional mains-side and load-side phase conductor connections. Electronic interruption units according to the invention and contacts of the mechanical isolating contact unit are provided in a similar manner between the additional mains-side and load-side phase conductor connections. The respective conductors (three phase conductors LI, L2, L3, neutral conductor N) are routed through the differential current unit ZCT.

[0117] Likewise, current sensor units and voltage detection (e.g. by first voltage sensor units) can be provided.

[0118] High-resistance refers to a state in which only a negligible current flows. In particular, high-resistance refers to resistance values ​​greater than 1 kiloohm, preferably greater than 10 kiloohms, 100 kiloohms, 1 megaohm, 10 megaohms, 100 megaohms, 1 gigaohm, or greater.

[0119] Low-resistance refers to a condition in which the current value specified on the protective device could flow. Specifically, low-resistance refers to resistance values ​​that are less than 10 ohms, preferably less than 1 ohm, 100 milliohms, 10 milliohms, 1 milliohm, or less.

[0120] The term "mechanical isolating contact unit MK" refers in particular to a (standard-compliant) isolating function, implemented by the isolating contact unit MK. The isolating function includes the following points: -Minimum air gap according to the standard (minimum distance between contacts), -(mechanical) contact position indicator of the contacts of the mechanical isolating contact unit,

[0121] -Release or release functionality, i.e. an operation 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.

[0122] In particular, release functionality means that the contacts can be opened by the control unit even if the mechanical handle is blocked (e.g. in the on state).

[0123] Furthermore, the standard-compliant isolating function can include the ability to lock the isolating contact unit or the handle in the switched on or off state.

[0124] The minimum clearance between the contacts of the isolating contact unit is essentially voltage-dependent. Other parameters include the degree of contamination, the type of field (homogeneous, inhomogeneous), and the air pressure or altitude above sea level.

[0125] There are corresponding (additional) regulations or standards for these minimum clearances or creepage distances. These (additional) regulations specify, for example, the minimum clearance for an inhomogeneous and a homogeneous (ideal) electric field for air, depending on the degree of contamination, for surge voltage resistance. Surge voltage resistance is the resistance when a corresponding surge 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).

[0126] For the purposes of the invention, the DIN EN 60947 and IEC 60947 series of standards may be relevant in particular for the isolating function and its properties. The isolating contact unit is advantageously characterized by a minimum air gap between the open isolating contacts in the position (open position, open contacts) depending on the rated impulse withstand voltage and the degree of pollution. The minimum air gap is in particular between (at least) 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 pollution degree 1 and in particular for inhomogeneous fields.

[0127] In particular, the term mechanical isolating contact unit does not refer to a relay contact.

[0128] The protective switching device can have a (particularly wireless) communication unit COM, which is connected to the control unit SE or is a part of it.

[0129] Furthermore, a display unit AE can be 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 a part of it. The display unit has visible display means on the protective switching device, in particular for displaying the high-resistance or low-resistance state of the electronic interruption unit EU. With a combined display and input unit, for example, the first or second (or third / further) tripping curve can be selected.

[0130] Alternatively or additionally, the first or second (or third / further) triggering curve can be selected, for example, via the communication unit COM.

[0131] The standard for standard-compliant residual current / differential current protection or its circuit breakers is, for example, the standard for residual current / differential current circuit breakers with built-in overcurrent protection (RCBOs) for domestic installations and similar applications, DIN EN 61009 (VDE 0664-20).

[0132] From the above-mentioned standard, version from 2016 (October), the following Table 2 (section 5.3.8.1

[0133] - Limits of the tripping and non-tripping time for alternating currents (rms values) for type AC and type A RCBOs, page 89).

[0134] Table 2 - Limit values ​​of the tripping and non-tripping time for alternating residual currents (rms values) for type AC and type A RCBOs

[0135] Further points and explanations can be found in the standard.

[0136] Figure 2 shows a diagram illustrating a current-time behavior. On the horizontal X-axis is the fault current (differential fault current = alternating fault currents according to the table above) I a in milliamperes [mA] , ie I a / [mA] . This fault current I a is shown logarithmically in the diagram.

[0137] The tripping time t in seconds is shown on the vertical Y-axis. The tripping time t (in seconds) is plotted logarithmically in the diagram. Figure 2 shows the (test) points and the resulting ranges resulting from the above-mentioned standard: a) the prevention of current flow in the low-voltage AC circuit OFF (current-time limit values ​​for tripping), b) the (safe) guidance of current flow in the low-voltage AC circuit ON (current limit values ​​for non-tripping), and the resulting tripping range AB are clearly shown.

[0138] The current-time limit values ​​of the tripping (area of ​​the avoidance of a current flow OFF - right area of ​​Figure 2 ) are marked in Figure 2 by a square standing on its tip (diamond shape), in the example:

[0139] First current-time limit value of tripping VI ( I an ) : 30mA at 300ms

[0140] Second current-time limit of tripping V2 : 60mA at 150ms

[0141] Third current-time limit of triggering V3 : 150mA at 40ms

[0142] Fourth current-time limit of tripping V4 : 250mA at 40ms

[0143] Fifth current-time limit of tripping V5 : 5A at 40ms

[0144] This means that with a residual current of or above 30 mA, the residual current device or the protective switching device according to the invention must prevent (interrupt) the flow of current within 300 ms.

[0145] For a residual current of 60 mA or more, the residual current device or the protective switching device according to the invention must prevent the current flow within 150 ms.

[0146] At a fault current of 150 mA (or more), the residual current device or the protective switching device according to the invention must prevent the current flow within 40 ms.

[0147] On the other hand, there is an area of ​​(safe) conduction of a current flow in the low-voltage AC circuit ON, which is determined by the current limit of non-tripping I ano (in the example equal to half of the "normal" fault current UI an ) of 15 mA (left-hand area of ​​Figure 2). This means that the residual current device or the protective switching device according to the invention must be able to carry a residual current of up to 15 mA for an unlimited period of time without preventing the current flow (therefore, in the example according to the standard, a current limit value, not a current-time limit value).

[0148] This results in a triggering area AB marked by the (test) points, which is indicated by a straight line as an example:

[0149] In the left area (ON) by a vertical line, marked by the current limit of non-tripping I ano (UI an ) of 15 mA;

[0150] In the right area (OFF) by vertical and horizontal straight lines resulting from the current-time limit values ​​of tripping VI, V2, V3 (V4, V5).

[0151] The tripping range AB is located between the non-tripping range ON and the tripping range (tripped range OFF). In this (transitional) range between (safe) current conduction and (safe) current avoidance, a tripping event usually occurs. This means that a current can still be conducted here, or a tripping event can occur here, although the precise (triggering) (concrete) tripping current-time limit is not further defined.

[0152] It is important that in the non-tripping area ON a current is (safely) carried (no tripping occurs) and in the tripping area (tripped area) OFF the current is safely avoided (tripping has previously occurred). This means that in the tripping area AB there are specific tripping current time values ​​at which tripping (prevention of current flow) is initiated by the protective switching device. These specific tripping current time values ​​form a tripping curve of the protective switching device. Figure 2 shows such a tripping curve as an example, and in the example a third tripping curve (standard). According to the invention it is now proposed that for the tripping area AB at least a first tripping curve and a second tripping curve can be selected within the tripping area AB, so that a different tripping behavior can be selected within the normatively identified tripping area AB.

[0153] In the example shown in Figure 2, a first tripping curve, Robust (close to the OFF tripping range), and a second tripping curve, Sensitive (close to the (safe) ON current flow range), are shown. These can be selected within the AB tripping range. This allows laypersons to select different, standard-compliant tripping behaviors within a normatively designated AB tripping range.

[0154] The first tripping curve Robust is close to the right-hand area of ​​the tripping OFF , 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).

[0155] This means that a trigger only occurs shortly before the (mandatory) trigger OFF area.

[0156] The second tripping curve, Sensitive, is close to the left-hand non-tripping ON range, so that even when leaving the non-tripping ON range, small (excessive) fault currents or the brief presence of fault currents can lead to tripping. Thus, tripping occurs shortly after leaving the non-tripping ON range.

[0157] Figure 2 also shows the third standard trigger curve within the trigger range AB, which is located approximately in the middle of the trigger range AB. This allows for the selection of an additional (or old) triggering behavior within the trigger range.

[0158] In a similar manner, additional tripping curves can be provided within the tripping range. This allows at least one additional tripping behavior to be selected within the tripping range. The tripping curves within the tripping range can be selected on or for the protective switching device, particularly by a layperson. The current-preventing tripping is advantageously performed by an electronic interruption unit (EU), thus enabling precise timing and compliance with the selected tripping curve, which is more complex to achieve with mechanical solutions (mechanical isolating contact unit).

[0159] The current-preventing tripping is advantageously achieved by a high-impedance state of the switching elements of the electronic interruption unit EU. This is especially true when the contacts of the mechanical isolating contact unit MK remain closed.

[0160] The invention and other aspects are described below in other words. Residual current circuit breakers according to standards have a tripping range, so that current devices that meet the same standard can nevertheless exhibit different tripping behavior.

[0161] The standard defines three ranges: A non-tripping range in which the protective switching device must safely conduct current. A second tripping range (tripped state) in which the current must be safely interrupted. An intermediate range is known as the tripping range. The tripping of the protective switching device must occur within this intermediate range in order to comply with the standard for the type. However, it is unclear how the tripping characteristic curve runs in this tripping range / intermediate range.

[0162] By means of the electronic measuring technology (differential current sensor unit) and the digital algorithms (control unit) of a new type of electronic protective switching device, various tripping characteristics can be realized according to the invention.

[0163] Figure 2 shows examples of what a possible implementation might look like. The three tripping characteristics or operating modes: "Standard," "Sensitive," and "Robust," could be offered and selected via a simplified setting option on the protective switching device.

[0164] The tripping behavior is defined by a corresponding digital algorithm (e.g., in the device firmware of the control unit). The invention now makes it possible to subsequently modify the tripping behavior of the protective switching device within existing standard limits.

[0165] The invention enables the tripping behavior to be easily modified without changing the standardized tripping characteristics of the protective switching device (which was used for the electrical planning of the system).

[0166] This provides a setting option for an electronic protective switching device that complies with existing standards.

[0167] Since the change in the triggering behavior is implemented in such a way that the standardized triggering range (the standardized triggering characteristic) is not changed, this possibility of change can be made available in a simplified form even to laypeople.

[0168] The differential current sensor unit ZCT determines the level of the fault current (differential current) I a of the (at least) two conductors L, N (connected to the protective device) of the low-voltage alternating current circuit, ie a, in particular instantaneous, fault current I a = I L - I N , where IL is the magnitude of the phase conductor current (in the phase conductor L), ie the magnitude of the current flowing between the mains-side phase conductor connection LG and the load-side phase conductor connection LL, and I N is the level of the neutral conductor current, ie the level of the current flowing between the mains-side neutral conductor connection NG and the load-side neutral conductor connection NL.

[0169] In a circuit, the magnitude of the phase conductor current I L (in the protective switching device) the level of the neutral conductor current I N (in the protective switching device), ie the level of the fault current I a = I L - IN is normally equal to zero.

[0170] The invention can be used particularly in Europe with alternating voltages of 230 volts phase conductor to neutral conductor or 400 volts between two phase conductors (not shown), effective values ​​of the alternating voltage.

[0171] The neutral conductor is usually grounded on the power source side. The earth-side neutral conductor connection is usually provided as a protective earth (PE) connection.

[0172] Although the invention has been illustrated and described in detail by the embodiment, the invention is not limited by the disclosed examples and other variations can be derived therefrom by a person skilled in the art without departing from the scope of the invention.

Claims

Patent claims 1 . Protective switching device for standard-compliant residual current protection for low-voltage alternating current circuits, comprising: - a housing (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 for a current flow of the conductors of the low-voltage alternating current circuit or an open state of the contacts for a current-preventing galvanic separation 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 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 the mechanical isolating contact unit (MK), whereby if the level of the fault current is exceeded, the avoidance of a current flow is initiated via specific tripping current-time values ​​forming a tripping curve, - that a standard for residual current / differential current circuit breakers specifies: a) current-time limit values ​​for tripping, so that a current flow in the low-voltage alternating current circuit must be avoided, and b) current limit values ​​for non-tripping, so that a current flow in the low-voltage alternating current circuit must be maintained, which identify a tripping area (AB), -that the actual tripping current-time values ​​are within the tripping range (AB ), - that the protective switching device is designed in such a way, that for the triggering range (AB) at least one first triggering curve (Robust) and one second triggering curve (Sensitive) can be selected within the triggering range (AB), so that a different triggering behavior can be selected within a normatively marked triggering range (AB).

2. Protective switching device (SG) according to claim 1, characterized in 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 a current flow in at least one conductor or a low-resistance state of the switching elements for current flow in the low-voltage AC circuit, that the control unit (SE) is connected to the electronic interruption unit (EU), that the protective switching device is designed in such a way that the current flow-preventing tripping takes place through a high-resistance state of the switching elements of the electronic interruption unit (EU), in particular when the contacts of the mechanical isolating contact unit (MK) continue to be closed.

3. Protective switching device (SG) according to claim 1 or 2, characterized in that the mechanical isolating contact unit (MK) is assigned to the load-side connection.

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

5. Protective switching device (SG) according to one of the preceding claims, characterized in that the mechanical isolating contact unit (MK) can be operated by a mechanical handle (HH) in order to switch an opening of the contacts or a closing of the contacts.

6. Protective switching device (SG) according to claim 5, characterized in that the contacts of the mechanical isolating contact unit (MK) have a release functionality such that the contacts are opened by the control unit (SE), even if the mechanical handle (HH) is blocked.

7. Protective switching device (SG) according to one of the preceding claims, characterized in that a third tripping curve (standard) can be selected within the tripping range for the tripping range, so that a further tripping behavior can be selected within the tripping range.

8. Protective switching device (SG) according to one of the preceding claims, characterized in that for the tripping range at least one further tripping curve can be selected within the tripping range, so that at least one further tripping behavior can be selected within the tripping range.

9. Protective switching device (SG) according to one of the preceding 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 built-in Overcurrent protection is, specifically DIN EN 61009-1 or 61008-1 (VDE 0664-20).

10. Protective switching device (SG) according to one of the preceding claims, characterized in that the control unit has a microprocessor and a memory, and that the tripping curves are stored in the control unit. 11 . Procedure for a protective switching device for standard-compliant residual current protection for low-voltage alternating current circuits, -that if the magnitude of a residual current is exceeded, the avoidance of a current flow is initiated via a tripping curve forming specific tripping current-time values, - that a standard for residual current / differential current circuit breakers specifies a) tripping current-time limits, so that a current flow in the low-voltage AC circuit must be avoided, and b) non-tripping current limits, so that a current flow in the low-voltage AC circuit must be maintained, which characterise a tripping range, - that the specific tripping current-time values ​​lie within the tripping range, - that for the triggering range at least one first triggering curve (Robust) and one second triggering curve (Sensitive) can be selected within the triggering range, so that a different triggering behavior can be selected within a normatively marked triggering range.

12. Method according to claim 11, characterized in that a third trigger curve (standard) can be selected within the trigger range.

13. Method according to claim 11 or 12, characterized in that the current flow in the protective switching device is avoided by a high-impedance state of switching elements of an electronic interruption unit (EU), in particular when at least one contact of a mechanical isolating contact unit (MK) continues to be in the closed state.

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