DE102019202474A1 - Residual current device and method - Google Patents

Abstract

The invention relates to a residual current device for a low-voltage circuit, comprising:
several conductors of a low-voltage circuit to be protected, which can be opened or closed by means of contacts,
a break unit for opening the contacts,
a control unit connected to the interruption unit,
a first summation current transformer whose primary side is formed by the conductors and which has a first secondary winding,
a first detection unit connected to the first secondary winding and, on the other hand, connected to the control unit,
a second summation current transformer whose primary side is likewise formed by the conductors and which has a second secondary winding,
- A second detection unit connected to the second secondary winding, which is on the other hand connected to the control unit. A selection unit is provided, which is connected to the control unit. The selection unit and the control unit are designed such that it is possible to switch between different types of residual current circuit breakers, so that the residual current protection unit has the functionality of the selected type.

Description

The invention relates to a fault current protection unit for a low-voltage circuit according to the preamble of patent claim 1, a system and a method for a fault current protection unit for a low-voltage circuit according to the preamble of claim 18.

Residual current circuit breakers for electrical circuits, in particular for low-voltage circuits or systems, are well known. Residual current circuit breakers are also referred to as residual current circuit breakers or residual current devices, in short RCD.

By low voltage is meant voltages up to 1000 volts AC or / and 1500 volts DC. By low voltage is meant in particular voltages that are greater than the low voltage, with values of 50 volts AC and 120 volts DC.

By circuits, especially for low voltage, are meant circuits for currents up to 6300 amps, more specifically currents up to 1600 amperes, 1200 amps, 630 amps, 125 amperes or 63 amps. In particular, nominal and / or turn-off currents are meant by said current values, i. the current that is normally passed over the circuit at most or in which the electrical circuit is usually interrupted, for example by a protective device, such as a circuit breaker or a circuit breaker.

Residual current circuit breakers detect the current sum in an electrical circuit, which is normally zero, and interrupt when a difference current value, i. a non-zero current sum exceeding a certain (differential) current value or fault current value or fault current value, the electrical circuit.

Almost all previous residual current circuit breakers have a summation current transformer whose primary winding is formed by the conductors of the circuit and whose secondary winding, the current sum or one equivalent of the current sum, e.g. in the form of a voltage, which is used directly or indirectly to interrupt the electrical circuit.

For this purpose, two or more conductors, usually forward and return conductors or external and neutral conductors in a single-phase AC network, all three outer conductor or all three outer conductor and the neutral conductor in a three-phase AC network, by one, usually having an annular core of ferromagnetic material, Current transformer led. Only the differential current is converted, i. a current deviating from outward and return current, from the conductors. Usually, the current sum in an electrical circuit is equal to zero. So fault currents can be detected.

If, for example, a current sinks to the earth from the energy side or the consumer side, a fault current is spoken of in this connection. An error occurs, for example, when an electrical connection exists from a phase conductor or outer conductor of the electrical circuit to earth. For example, when a person touches the phase conductor. Then a part of the electric current does not flow back as usual over the neutral conductor or neutral, but over the person and the earth. This fault current can now be detected with the aid of the summation current transformer, since the sum of inflowing and outflowing current detected in terms of amount is not equal to zero. About a relay or a holding magnet release or an interruption unit, for example with connected mechanism, an interruption of the circuit, for example at least one, a part or all lines is effected. Residual current circuit breaker for detecting AC residual currents are generally from the document DE 44 32 643 A1 known.

The main function of residual current circuit breakers is to protect persons from electrical currents (electric shock), as well as equipment, machinery or buildings from fire due to electrical insulation faults.

If the residual current circuit breaker or its summation current transformer is designed such that the secondary-side energy is sufficient for actuating a trip unit or an interrupt unit or a trigger, then such residual current circuit breaker is called mains voltage independent; otherwise mains voltage dependent.

If a power supply is provided for supplying power to a fault current detection, then it is mains-voltage-dependent fault current circuit breaker. These are required, for example, to detect fault currents in DC voltage networks as well as mixed DC / AC networks or in circuits with high frequencies.

A residual current circuit breaker consists essentially of the function groups summation current transformer, detection unit, control unit, interruption unit / contacts. Furthermore, a test circuit with test button and test resistor is usually provided. The functionality of the residual current circuit breaker or fault current Protective device can be checked via the test button.

Residual current circuit breakers come in different types, which are designated by letters or letter combinations, such as AC . A . F . G . K . S . B . B + , Each type detects a certain type of fault currents or is intended for certain fault currents. The residual current circuit breakers are distinguished in terms of their suitability for detecting different types of fault current.

In general, residual current circuit breakers are 2-pole for phase and neutral conductors (L + N), 3-pole for three phase conductors ( L1 . L2 . L3 ) and 4-pole for three phase conductors and neutral conductors ( L1 . L2 . L3 , N) known.

For example, AC residual current circuit breakers detect only purely sinusoidal fault currents.
Residual current device type A detects both purely sinusoidal AC residual currents and pulsating DC residual currents.
Type F fault current circuit breakers are mixed frequency sensitive residual current protective devices. They detect all types of residual current, such as type A, but are also suitable for detecting residual currents consisting of a frequency mixture of frequencies up to 1 kHz.
A type K residual current circuit breaker incorporates the characteristics of type A, but it is short-delayed in its turn-off behavior.
Type S residual current circuit breakers are selective residual current circuit breakers that can be staggered in the rated differential current as well as in the tripping time. Type B residual current protective devices, in addition to the detection of type F fault current circuits, are also used to detect smooth DC residual currents. Furthermore, they are suitable for fault currents with frequencies up to 2 kHz.
The same conditions apply to Type B residual current protective devices as to Type B residual current protective devices. Only the frequency range for the detection of residual currents is valid for an extended range up to 20 kHz. The triggering takes place within this frequency range below 420 mA.

The characteristics of each type are usually defined by standards.

Such residual current circuit breakers partly have two summation current transformers or detection circuits in order to detect the different fault current types and thus to provide a type-appropriate functionality.

Usually residual current circuit breakers are built for their use precisely for a type of fault currents to be detected. This means that a type-specific residual current circuit breaker is available for every application.

If the application changes in an existing circuit or installation, a residual current circuit breaker with the highest functionality is to be used from the outset, although this is not (yet) required, or the residual current circuit breaker has to be exchanged for the new application, which is costly.

Object of the present invention is to improve a residual current circuit breaker of the type mentioned, in particular to provide a broader functionality.

This object is achieved by a residual current device with the features of claim 1, a system according to claim 17 and by a method according to claim 18.

By fault current protection unit is meant in particular a device for the detection of fault or differential currents.

• - mehrere Leiter (mit mehrere Leiter sind mindestens zwei Leiter gemeint) eines zu schützenden Niederspannungsstromkreises, - einen ersten Summenstromwandler, dessen Primärseite durch die Leiter gebildet ist und der eine erste Sekundärwicklung aufweist,
• - eine mit der ersten Sekundärwicklung verbundene erste Detektionseinheit, die andererseits mit einer Steuerungseinheit verbunden ist,
• - einen zweiten Summenstromwandler, dessen Primärseite ebenfalls durch die Leiter gebildet ist und der eine zweite Sekundärwicklung aufweist,
• - eine mit der zweiten Sekundärwicklung verbundene zweite Detektionseinheit, die andererseits mit der Steuerungseinheit verbunden ist.

Erfindungsgemäß ist eine Auswahleinheit vorgesehen. Die Steuerungseinheit ist mit der Auswahleinheit verbunden. Die die Steuerungseinheit und die Auswahleinheit sind derart ausgestaltet, dass zwischen verschiedenen Typen von Fehlerstromschutzschaltern umgeschaltet werden kann. Die Fehlerstromschutzeinheit weist dann die Funktionalität des ausgewählten Typs auf.
Dies hat den Vorteil, dass eine Fehlerstromschutzeinheit mit mehreren Funktionalitäten / Typarten zur Verfügung steht. So kann für unterschiedliche Applikationen mit unterschiedlichen Fehlerstromformen die gleiche Fehlerstromschutzeinheit verwendet werden. Dadurch reduziert sich die Anzahl an zur Verfügung zu stellenden bzw. anzubietenden Fehlerstromschutzschaltern. Entwicklungs- und Lagerkosten für unterschiedliche Typen können reduziert werden. Je nach Applikation kann der entsprechende Typ an der Fehlerstromschutzeinheit eingestellt werden.According to the invention, a residual current device is provided for a low-voltage circuit, comprising:

• a plurality of conductors (at least two conductors are meant by a plurality of conductors) of a low-voltage circuit to be protected, a first summation current transformer whose primary side is formed by the conductors and which has a first secondary winding,
• a first detection unit connected to the first secondary winding and connected to a control unit on the other hand,
• a second summation current transformer whose primary side is likewise formed by the conductors and which has a second secondary winding,
• - A second detection unit connected to the second secondary winding, which is on the other hand connected to the control unit.

According to the invention, a selection unit is provided. The control unit is connected to the selection unit. The control unit and the selection unit are designed such that it is possible to switch between different types of residual current circuit breakers. The residual current device then has the functionality of the selected type.
This has the advantage that a residual current device with multiple functionalities / Typarten for Available. Thus, the same fault current protection unit can be used for different applications with different fault current forms. This reduces the number of residual current circuit breakers to be made available or to be offered. Development and storage costs for different types can be reduced. Depending on the application, the corresponding type can be set on the residual current device.

Advantageous embodiments of the invention are specified in the subclaims.

In an advantageous embodiment of the invention, the residual current device has the functionalities of the types B and B + on, so between the types B and B + can be switched.
This has the special advantage that with a residual current device the two common types can be covered, which simplifies the storage, the ordering process and the configuration.

In an advantageous embodiment of the invention, the residual current device has the functionalities of the types AC, A, B and B +, so that it is possible to switch between these types.

This has the particular advantage that with a residual current device a larger range of different types can be covered, which simplifies the storage, the ordering process and the configuration.

In an advantageous embodiment of the invention, the residual current device has at least two functionalities, optionally three, four, five, six, seven or eight functionalities of the types AC . A, F . G . K . S . B . B + so that at least two of the types can be selected. This has the particular advantage that with the residual current device a wide variety of types can be covered, which simplifies the storage, the ordering process and project planning.

In an advantageous embodiment of the invention, the residual current device receives a power supply through at least part of the conductors, in particular by means of a power supply, more particularly a switched-mode power supply.
This has the particular advantage that a simple power supply is available, so that, for example, a mains voltage-independent and a mains voltage-dependent detection circuit can be realized; a simple power supply is available for the control unit.

• - ein erstes Tiefpassfilter oder/und einen Verstärker auf,
• - eine Ansteuerungseinheit, zur Erzeugung eines Stromes in der ersten Sekundärwicklung.

Dies hat den besonderen Vorteil, dass eine einfache Realisierung für Detektionskreis gegeben ist, mit der beispielsweise Fehlerströme in Gleicherstromkreisen erkannt werden können.In an advantageous embodiment of the invention, the first detection unit comprises:

• a first low-pass filter and / or an amplifier,
• - A drive unit, for generating a current in the first secondary winding.

This has the particular advantage that a simple implementation is provided for detection circuit, with the example of fault currents can be detected in DC circuits.

In an advantageous embodiment of the invention, a second low-pass filter is provided.
This has the particular advantage of enabling better detection of fault currents, especially for certain types of residual current circuit breakers, more specifically for types and B and B +.

In an advantageous embodiment of the invention, the second detection unit has a third low-pass filter and / or an amplifier.
This has the particular advantage that a better recognition, in particular of alternating fault currents, is made possible.

In an advantageous embodiment of the invention, the control unit has a microprocessor.
This has the particular advantage that a simple microprocessor-based evaluation is made possible, which allows various types of functions easily.

In an advantageous embodiment of the invention, the control unit has an analog-to-digital converter.
This has the particular advantage of allowing easy digital processing of the fault current readings.

In an advantageous embodiment of the invention, the selection unit has a rotary switch, slide switch or push-button, for selecting the type of residual current circuit breaker.
This has the particular advantage that a simple adjustment of the type is given. In particular, a rotary switch or slide switch makes it easy to read off the set type.

In an advantageous embodiment of the invention, the control unit is designed such that the functionality of a first selected type by sole evaluation of the signal of the secondary winding of only one summation current transformer takes place.
This has the particular advantage that a shutdown of a portion of the residual current circuit breaker can be performed and thus energy consumption reduction of the residual current circuit breaker takes place. A detection circuit that is not required for a type can simply be switched off.

In an advantageous embodiment of the invention, the functionality of a second selected type by sole evaluation of the signal of the secondary winding of the other summation current transformer or
that the functionality of the second selected type is carried out by evaluating the signals of the secondary windings of both summation current transformer.
This has the particular advantage that energy can be saved here as well. In addition, the type switching can be realized very easily, for example by switching the detection circuits.

In an advantageous embodiment of the invention, the fault current protection unit has contacts which can be opened or closed, so that a current flow through the conductors is interrupted or made possible. Furthermore, an interruption unit for opening the contacts is provided, which is connected to the control unit.
This has the particular advantage that there is a compact fault current protection unit for fault currents, which in the case of fault currents exceeding a residual current limit, performs an interruption of the electrical circuit itself, such as a residual current circuit breaker.

In an advantageous embodiment of the invention, the residual current device is designed as a module which is connectable to a switching device, in particular a circuit breaker.
This has the particular advantage that a switching device, such as a circuit breaker can be extended to a residual current circuit protection unit according to the invention, wherein different types of residual current circuit breakers are selectable.

In an advantageous embodiment of the modular design of the residual current device, this has an interface, such as a mechanical or (and) electrical interface, which signals the exceeding of a residual current limit, in particular to the switching device.

The mechanical interface can be designed, for example, as a plunger. The electrical interface, for example, as a switched relay contact. The electrical interface can be connected by a line, such as a two-wire line, Koaxilkabel etc. with the switching device. For example, by closing a contact in the residual current device, an interruption of the electrical circuit in the switching device can be initiated.
This has the particular advantage that a particularly simple triggering of a connected switching device, such as a circuit breaker is given.

According to the invention, a system comprising a fault current protection unit in conjunction with a switching device, in particular a circuit breaker, is also claimed. Both devices are in operative connection during operation.

• - ein erster und ein zweiter Detektionskreis vorgesehen ist, mit denen Differenzströme der Leiter ermittelbar sind,
• - bei Überschreitung eines Differenzstromschwellwertes ein Auslösesignal zur Unterbrechung der Leiter des Niederspannungsstromkreises abgegeben wird, beispielsweise über eine Schnittstelle, wie eine mechanische oder elektrische Schnittstelle, oder direkt zu einer Unterbrechungseinheit, so dass eine Unterbrechung des Stromkreises zumindest imitiert wird. Erfindungsgemäß sind mindestens zwei, wahlweise drei, vier, fünf, sechs, sieben, acht oder mehr, unterschiedliche Typen von Fehlerstromschutzschaltercharakteristiken auswählbar.

According to the invention, a corresponding method is claimed for a residual current device for a low-voltage circuit with a plurality of conductors, in which:

• a first and a second detection circuit is provided, with which differential currents of the conductors can be determined,
• - When exceeding a Differenzstromschwellwertes a trigger signal for interrupting the head of the low-voltage circuit is discharged, for example via an interface, such as a mechanical or electrical interface, or directly to an interruption unit, so that an interruption of the circuit is at least mimicked. According to the invention, at least two, optionally three, four, five, six, seven, eight or more, different types of residual current circuit breaker characteristics are selectable.

All embodiments, both in dependent form relative to the claims 1 and 18, as well as referring back only to individual features or feature combinations of claims, cause an improvement in the functionality of a residual current device, in particular the provision of a type selection of a residual current circuit breaker.

The described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments, which will be explained in connection with the drawing.

• 1 eine Funktionsübersicht einer Auswahl verschiedener Typen von Fehlerstromschutzschaltern,
• 2 ein erstes Blockschaltbild einer Fehlerstromschutzeinheit ,
• 3 ein zweites Blockschaltbild einer Fehlerstromschutzeinheit,
• 4 ein drittes Blockschaltbild einer Fehlerstromschutzeinheit,
• 5 ein viertes Blockschaltbild einer Fehlerstromschutzeinheit,
• 6 eine erste Ansicht einer Fehlerstromschutzeinheit ,
• 7 eine zweite Ansicht einer Fehlerstromschutzeinheit,
• 8 eine dritte Ansicht einer Fehlerstromschutzeinheit,
• 9 eine vierte Ansicht einer Fehlerstromschutzeinheit,
• 10 ein fünftes Blockschaltbild mit einer Fehlerstromschutzeinheit.

The drawing shows:

• 1 a functional overview of a selection of different types of residual current circuit breakers,
• 2 a first block diagram of a residual current device,
• 3 a second block diagram of a residual current device,
• 4 a third block diagram of a residual current device,
• 5 a fourth block diagram of a residual current device,
• 6 a first view of a residual current device,
• 7 a second view of a residual current device,
• 8th a third view of a residual current device,
• 9 a fourth view of a residual current device,
• 10 a fifth block diagram with a residual current device.

1 shows a functional overview of a selection of different types of residual current circuit breakers, especially the types AC . A . F . B and B + ,

• - rein sinusförmige Wechselfehlerströme,
• - Halbwellen-Wechselfehlerströme
• - Angeschnittene (Phasenanschnitt) Wechselfehlerströme
• - Pulsierende Gleichfehlerströme,
• - höherfrequente Fehlerströme
• - Glatte Gleichfehlerströme

In the first column "current form" the current forms are represented by symbols, from top to bottom:

• - purely sinusoidal AC fault currents,
• - Half-wave alternating fault currents
• - Ancillary (phase angle) AC fault currents
• - pulsating DC residual currents,
• - higher frequency fault currents
• - Smooth DC residual currents

In the second column, the "proper function of residual current device of the type" AC . A . F . B and B + specified. The named types are assigned respective detection symbols.
Furthermore, it is indicated which type detects which current form.

In the third column "tripping current" it is indicated which tripping currents or tripping current ranges and, if applicable, lead angle (phase angle) are assigned to the respective current forms, if appropriate with reference to the differential nominal current IΔn.

With type of residual current circuit breaker is meant in particular a characterization with respect to the detected current waveform (s) and / or the detected current frequency range. Optionally additionally with regard to the detected current angle.

• - mehrere Eingangsanschlüsse 1, 3, 5, NE, für den energiequellenseitigen Anschluss der Fehlerstromschutzeinheit respektive des erfindungsgemäßen Fehlerstromschutzschalters FI an eine Energiequelle, beispielsweise einen Niederspannungsstromkreis bzw. ein Niederspannungsnetz;
• - mehrere Ausgangsanschlüsse 2, 4, 6, NA für den energiesenkenseitigen Anschluss der Fehlerstromschutzeinheit FI an eine Energiesenke, beispielsweise einen Verbraucher;
• - mehrere Leiter L1, L2, L3, N eines zu schützenden Niederspannungsstromkreises, wobei ein erster Leiter L1 zwischen erstem Eingangsanschluss 1 und ersten Ausgangsanschluss 2 geschaltet ist, dito ein zweiter Leiter L2 zwischen zweitem Eingangsanschluss 3 und zweitem Ausgangsanschluss 4, ein dritter Leiter L3 zwischen drittem Eingangsanschluss 5 und drittem Ausgangsanschluss 6 geschaltet ist, ein vierter Leiter N, z.B. Neutralleiter, zwischen vierten Eingangsanschluss NE und vierten Ausgangsanschluss NA geschaltet ist;
• - wobei z.B. die ersten bis dritten Leiter L1, L2, L3 Phasenleiter und der vierte Leiter N ein Neutralleiter bzw. Nullleiter eines beispielsweise Dreiphasenwechselstromkreises sind;
• - mehrere, z.B. erste bis vierte Kontakte K1, K2, K3, KN mit denen die ersten bis vierten Leiter L1, L2, L3, N elektrisch geöffnet oder geschlossen werden können, wobei ein Kontakt einem Leiter zugeordnet ist;
• - eine mit den Kontakten K1, K2, K3, KN verbundene Unterbrechungseinheit 10, zum Öffnen (und ggfs. Schließen) der Kontakte K1, K2, K3, KN;
• - einen mit der Unterbrechungseinheit 10 verbundene Steuerungseinheit 20, die ggfs. eine Öffnung der Kontakte K1, K2, K3, KN bewirkt;
• - einen ersten Summenstromwandler ZCT1, dessen Primärseite durch die Leiter L1, L2, L3, N gebildet ist, wobei die Leiter durch den Summenstromwandler ZCT1 hindurchgeführt sind, der Summenstromwandler beispielsweise als Ringkern 40, z.B. aus ferromagnetischen Material ausgeführt ist, und der eine erste Sekundärwicklung aufweist, die beispielsweise mehrere Windungen aufweist, wie angedeutet;
• - eine mit der ersten Sekundärwicklung verbundene erste Detektionseinheit 50, die andererseits mit der Steuerungseinheit 20 verbunden ist,
• - einen zweiten Summenstromwandler ZCT2, dessen Primärseite ebenfalls durch die Leiter L1, L2, L3, N gebildet ist, wobei die Leiter durch den zweiten Summenstromwandler ZCT2 hindurchgeführt sind, der Summenstromwandler beispielsweise als Ringkern 60, z.B. aus ferromagnetischen Material ausgeführt ist, und der eine zweite Sekundärwicklung aufweist, die beispielsweise mehrere Windungen aufweist, wie angedeutet;
• - eine mit der zweiten Sekundärwicklung verbundene zweite Detektionseinheit 70, die andererseits mit der Steuerungseinheit 20 verbunden ist.

Es ist eine Auswahleinheit 30 vorgesehen. Die Auswahleinheit 30 ist mit der Steuerungseinheit 20 verbunden. Die Auswahleinheit 30 und die Steuerungseinheit 20 sind derart ausgestaltet sind, dass zwischen verschiedenen Typen von Fehlerstromschutzschaltern umgeschaltet werden kann, so dass die Fehlerstromschutzeinheit die Funktionalität des ausgewählten Typs, siehe beispielsweise 1, aufweist. 2 shows a first block diagram of a residual current device FI, comprising:

• - several input connections 1 . 3 . 5 . NE for the power-source-side connection of the fault current protection unit or of the residual current circuit breaker FI according to the invention to an energy source, for example a low-voltage circuit or a low-voltage network;
• - several output connections 2 . 4 . 6 . N / A for the power sink side connection of the residual current device FI to an energy sink, for example a consumer;
• - several conductors L1 . L2 . L3 . N a low-voltage circuit to be protected, a first conductor L1 between the first input connection 1 and first output terminal 2 is switched, ditto a second leader L2 between second input terminal 3 and second output terminal 4 , a third leader L3 between third input connection 5 and third output terminal 6 is connected, a fourth conductor N, eg neutral conductor, is connected between the fourth input terminal NE and the fourth output terminal NA;
• where eg the first to third conductors L1 . L2 . L3 Phase conductor and the fourth conductor N are a neutral conductor or neutral, for example, a three-phase AC circuit;
• - Several, eg first to fourth contacts K1 . K2 . K3 , KN with which the first to fourth conductors L1 . L2 . L3 . N can be electrically opened or closed, wherein a contact is associated with a conductor;
• - one with the contacts K1 . K2 . K3 , KN connected interrupt unit 10 , to open (and if necessary close) the contacts K1 . K2 . K3 . KN ;
• - one with the interrupt unit 10 connected control unit 20 , if necessary, an opening of the contacts K1 . K2 . K3 . KN causes;
• - A first summation current transformer ZCT1 whose primary side is through the ladder L1 . L2 . L3 . N is formed, wherein the conductors through the summation current transformer ZCT1 passed through, the summation current transformer, for example, as a toroidal core 40 , For example, made of ferromagnetic material, and having a first secondary winding having, for example, a plurality of turns, as indicated;
• - A first detection unit connected to the first secondary winding 50 on the other hand with the control unit 20 connected is,
• - A second summation current transformer ZCT2 whose primary side is also through the ladder L1 . L2 . L3 , N, wherein the conductors through the second summation current transformer ZCT2 passed through, the summation current transformer, for example, as a toroidal core 60 , For example, made of ferromagnetic material, and having a second secondary winding having, for example, a plurality of turns, as indicated;
• - a second detection unit connected to the second secondary winding 70 on the other hand with the control unit 20 connected is.

It is a selection unit 30 intended. The selection unit 30 is with the control unit 20 connected. The selection unit 30 and the control unit 20 are configured to switch between different types of residual current circuit breakers so that the residual current device will have the functionality of the type selected, see for example 1 , having.

Functionally, a fault current induced in the first or second secondary winding, which exceeds, for example, a fault current value, generates an interruption of at least one, part or all of the conductors, i. an opening of one, part or all of the contacts so that the electrical circuit is broken. The interruption can be supported by a mechanism, not shown.

The control unit 20 may include other units, such as one or more analog-to-digital converters 21 , a value calculation unit 22 or / and a threshold comparison unit 22 ,

The selection unit 30 For example, it may include a rotary switch, slide switch, pushbutton switch, or other switch to select the type of residual current circuit breaker.

The first detection unit 50 can, for example, a first low-pass filter 51 , a second low-pass filter 52 or / and a first amplifier 53 have, for example, connected in series. The first detection unit 50 may further comprise a drive unit for generating a current in the first secondary winding, for example consisting of a saturation detector 54 which detects when the first summation current transformer saturates and an excitation unit 55 which generates a current in the first secondary winding depending on the saturation of the summation current transformer. With the drive unit, for example, fault currents can be determined in DC circuits.

The first summation current transformer ZCT1 may, for example, a different kind of fault currents than the second summation current transformer ZCT2 be designed. The first summation current transformer ZCT1 For example, together with the first detection unit 50 carry out an evaluation with smooth Gleichstromstromströmen.

The second detection unit 70 may, for example, a third low-pass filter 71 or / and a second amplifier 72 respectively. These filter and / or amplify the differential current generated in the second secondary winding and lead in the control unit 20 to.

Furthermore, a power supply 80 be provided, for example, a switching power supply, with at least a portion of the conductors, in particular with the first to fourth conductors L1 . L2 . L3 . N , connected is. The power supply unit serves to supply energy to at least a part of the units of the residual current circuit breaker, for example the control unit 20 , the first detection unit 50 and / or the second detection unit 70 ,

The first detection unit 50 can be configured for example as an active detection unit or mains voltage-dependent residual current circuit breaker unit.

The second detection unit 70 can be configured, for example, as a passive detection unit or mains voltage-independent residual current circuit breaker unit.

With the realization according to 2 It is possible to choose between at least two residual current circuit breaker types.

The control unit 20 captures the selection of the selection unit 30 ,
The control unit 20 detects the output signals of the first 50 and second detection unit 70 ,
The first detection unit 50 may be a current (excitation current) in the first summation current transformer ZCT1 generate to modulate the fault current in the summation current transformer to allow detection of eg DC fault currents.
The second detection unit 70 can directly a current in the second summation current transformer ZCT2 to capture.
With the first, second and / or third filters 51 . 52 . 71 Different frequency selections can be made.

If, for example, by the selection unit 30 a residual current device of the type AC or A is selected, for example, a fault current exceeding solely by the second detection unit 70 in Connection with the control unit 20 be determined. The first detection unit 50 can be switched off, for example.

If, for example, by the selection unit 30 A type B or B + residual current circuit breaker is selected, for example, a fault current exceeded by evaluation of the fault currents of the first and second detection unit 50 . 70 in connection with the control unit 20 be determined.

In other cases or alternatively, only an evaluation by the first detection unit 50 in connection with the control unit 20 be performed. The second detection unit 70 can be switched off, for example.

3 shows a block diagram according to 2 , with the difference that all units in a housing 200 arranged, for example, as a module, with the exception of the interruption unit 10 and contacts K1 . K2 . K3 , CN.
The housing 200 , eg as a module, can be connected to a switching device, such as a circuit breaker.

The connection through an electrical connection 230 and / or a mechanical connection, for example in the form of a plunger. The connection may have a housing-side interface.

The interruption unit 10 including contacts K1 . K2 . K3 , KN and, if necessary, further units are part of a switching device, such as a circuit breaker.

With circuit breaker in this case a protection device is meant that works much like a fuse. Circuit breakers monitor the current flowing through them through at least one conductor and interrupt the electrical current to an energy sink or consumer, which is referred to as tripping, when protection parameters such as current limits or current-time-out limits, i. if a current value exists for a certain period of time, be exceeded. The interruption occurs, for example, through contacts of the circuit breaker, which are opened.

In particular for low-voltage circuits or networks there are different types of circuit breakers depending on the level of the intended electrical current in the electric circuit. With circuit breaker according to the invention in particular switches are meant, as used in low-voltage systems for currents of 63 to 6300 amps. More specifically, closed circuit breakers are used for currents of 63 to 1600 amps, in particular from 125 to 630 or 1200 amps. Open circuit breakers are used in particular for currents from 630 to 6300 amps, more specifically from 1200 to 6300 amps.
Open Circuit Breakers are also referred to as Air Circuit Breaker, ACB for short, and Molded Case Circuit Breaker or Molded Case Circuit Breaker, MCCB for short circuit breakers.

With circuit breaker according to the invention, in particular circuit breaker with an electronic trip unit, also referred to as Electronic Trip Unit, short ETU, meant.

4 shows an embodiment according to 2 , with the following differences.
The first detection unit 50 is in a first detection subunit 501 and a second detection subunit 502 divided up.
The first detection subunit 501 includes functions for fault current detection. It may, for example, have the filters or and amplifiers, such as the units 51 . 52 or and 53 ,
The second detection subunit 502 Here is the drive unit, which is the units / saturation detector 54 or / and excitation unit 55 can have.

The control unit 20 only has a microprocessor MCU. This can have, for example, at its inputs AI integrated analog-to-digital converter.

The selection unit 30 is designed as a rotary switch or BCD switch, with which a user can select the residual current device type. It has 4 outputs, with 4 inputs DI of the control unit 20 are connected.
The selection unit may supply a supply voltage VCC from the power supply 80 receive.

The power supply 80 has several units. First, a rectifier unit 81 , followed by a DC-DC converter 82 as a DC-DC converter, followed by a DC regulator 83 such as a low dropout regulator or LDO. At the output of this power supply, a supply voltage VCC is provided, that of the control unit 20 as well as further units or circuit parts can be made available.

The interruption unit 10 For example, may have a coil or a relay with which the contacts are opened. Alternatively, a plunger can be moved, for example, at least partially realizes a mechanical interface.

The core of the first and / or second summation current transformer 40 . 60 can consist of nanocrystalline material.

In the detection units 50 . 501 . 502 . 70 or amplifiers 53 . 72 Operational amplifiers can be used. The filters / low pass filters 51 . 52 . 71 can also be realized by means of operational amplifier. The drive unit 502 or. units 54 . 55 / Saturation detector 54 / Excitation unit 55 / may also have operational amplifiers.

The detection units 50 . 70 may have resistances, as indicated.

5 shows a block diagram according to 4 , with the difference that all units, except for the contacts K1 . K2 . K3 , KN, in a housing 300 are arranged.
The housing 300 can be designed as a module that with a switching device 400 how a circuit breaker communicates.
The connection is for example by a mechanical interface or connection 330 , For example in the form of a plunger realized. The plunger is eg by a coil in the interruption unit 10 actuated.
The contacts K1 . K2 . K3 , KN and possibly other units are part of the switching device 400 like a circuit breaker. The plunger causes a triggering of the contacts of the switching device 400 , in particular circuit breaker. The switching device may have further units, such as a mechanism, not shown, to use the movement of the plunger for triggering.

Alternatively, an electrical triggering can be carried out, for example by means of an electronic trip unit of the switching device, such. Circuit breaker.

6 shows a first exemplary view of a residual current device FI. This indicates, in addition to the settings for the fault current or fault response current 91 or / and the tripping time or limit non-response time 92 , a selection unit 30 , For example, in the form of a rotary switch on. With these can be between at least two residual current circuit breaker types, for example type B and B + to be switched.

7 a second exemplary view according to 6 , with the difference that between 4 different types of residual current circuit breaker can be switched. For example, between type AC . A . B and B + , Any other combination of types is also conceivable, as well as any other number.

8th shows an arrangement of a system comprising a residual current device in modular design 300 in conjunction with a switching device 400 such as a circuit breaker.

9 shows a different view according to 7 , where a switching output X1 a relay with a series connection of a voltage source U , a fuse F and a first lamp or light emitting diode L1 , optionally a parallel connection of a second lamp or light emitting diode L2 , connected is. For example, the exceeding of a residual current limit value can be signaled.

10 shows an arrangement of another system, comprising a residual current device 500 , with an external summation current transformer ZCT , as well as an electrical connection 900 to a switching device 800 as a circuit breaker, being the electrical connection with a unit 700 connected to the switching device, to trigger the switching device. The unit 700 For example, it can be an electrical overvoltage or undervoltage release. The residual current device 500 , all units in the housing 200 according to 3 can, with the exception of the summation current transformer ZCT, can on a top hat rail 600 be mounted.

The invention has the advantage that the functionality of a fault current protection unit or a residual current circuit breaker is increased. With the invention, the variety of types of residual current circuit breakers can be reduced, which reduces development, production and storage costs.

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

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4432643 A1 [0008]

Claims (18)

Residual current device (RCD) for a low-voltage circuit, comprising: - a plurality of conductors (L1, L2, L3, N) of a low-voltage circuit to be protected, - a first summation current transformer (ZCT1) whose primary side is formed by the conductors (L1, L2, L3, N) and having a first secondary winding, - a first detection unit (50) connected to the first secondary winding and, on the other hand, connected to a control unit (20), - a second summation current transformer (ZCT2) whose primary side is also connected through the conductors (L1, L2 , L3, N) and having a second secondary winding, - a second detection unit (70) connected to the second secondary winding and, on the other hand, connected to the control unit (20), characterized in that a selection unit (30) is provided, in that the control unit (20) is connected to the selection unit (30) such that the selection unit (30) and the control unit (20) are designed in such a way tet is that can be switched between different types of residual current circuit breakers, so that the residual current device has the functionality of the selected type. Residual current device (FI) after Claim 1 , characterized in that the residual current device has the functions of types B and B +, so that it is possible to switch between types B and B +. Residual current device (FI) after Claim 1 , characterized in that the fault current protection unit has the functionalities of the types AC, A, B and B +, so that it is possible to switch between these types. Residual current device (FI) after Claim 1 , characterized in that the residual current device comprises at least two functionalities of the types AC, A, F, G, K, S, B, B +, so that at least two of the types can be selected. Residual-current device (FI) according to one of the preceding claims, characterized in that the residual current device receives a power supply through at least part of the conductors (L1, L2, L3, N), in particular by means of a power supply (80). Residual-current device (FI) according to one of the preceding claims, characterized in that the first detection unit (50) comprises: - a first low-pass filter (51) and / or an amplifier (53), - has a drive unit for generating a current in the first secondary winding. Residual current device (FI) after Claim 6 , characterized in that a second low-pass filter (52) is provided. Residual-current device (FI) according to one of the preceding claims, characterized in that the second detection unit (70) has a third low-pass filter (71) and / or an amplifier (72). Residual-current device (FI) according to one of the preceding claims, characterized in that the control unit (20) comprises a microprocessor (MCU). Residual-current device (FI) according to one of the preceding claims, characterized in that the control unit (20 has an analog-to-digital converter (21). Residual-current device (FI) according to one of the preceding claims, characterized in that the selection unit (30) has a rotary switch or push-button switch for selecting the type of residual current circuit breaker. Residual-current device (FI) according to one of the preceding claims, characterized in that the control unit (20) is configured such that the functionality of a first selected type by sole evaluation of the signal of the secondary winding of only one summation current transformer takes place. Residual current device (FI) after Claim 12 , characterized in that the functionality of a second selected type by sole evaluation of the signal of the secondary winding of the other summation current transformer takes place or that the functionality of the second selected type by evaluating the signals of the secondary windings of both summation current transformer takes place. Residual current device (FI) according to one of the preceding claims, characterized in that the conductors can be opened or closed by contacts (K1, K2, K3, KN) that an interruption unit (10) for opening the contacts (K1, K2, K3, KN) is provided, that the interruption unit (10) is connected to the control unit (20). Residual current device (FI) according to one of the preceding Claims 1 to 13 , characterized in that the residual current device is designed as a module that is connectable to a switching device, in particular a circuit breaker. Residual current device (FI) after Claim 15 , characterized in that the residual current device has an interface which signals when exceeding a residual current limit. A system comprising a residual current device according to any one of Claims 1 to 13 . 15 or 16 , which is in operative connection with a switching device, in particular a circuit breaker. Method for a residual-current-protective device (FI) for a multi-conductor low-voltage circuit (L1, L2, L3, N), in which: - a first and a second detection circuit (50, 70) is provided, with which differential currents of the conductors can be determined, when a differential current threshold is exceeded, a trip signal is sent to interrupt the conductors of the low voltage circuit, characterized in that at least two different types of residual current circuit breaker characteristics are selectable.

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