DE102019212661A1 - Electronic circuit breaker and method - Google Patents

Abstract

The invention relates to an electronic protective switching device (SG) for a low-voltage circuit, having: - first connections (LE1, LE2, LE3, LEN) for the low-voltage circuit, which are connected via main current paths (HB1, HB2, HB3, HBN) to second connections (LA1, LA2 , LA3, LAN) for the low-voltage circuit; - a trip unit (AE) with contact system (KS), which can interrupt the main current paths (HB1, HB2, HB3, HBN) in order to interrupt the low-voltage circuit; - a sensor unit ( SE), which records at least one electronic variable of the main current paths (HB1, HB2, HB3, HBN) or of the low-voltage circuit; - a control unit (MCU), which is connected to the sensor unit (SE) and the trigger unit (AE) and if exceeded at least one limit value of the electronic variable causes an interruption of the main current paths (HB1, HB2, HB3, HBN) by means of the contact system (KS); - a power supply unit (NT) connected to the control unit (MCU) and the main current paths (HB1, HB2, HB3, HBN) are connected to supply power to the control unit (MCU); - an interface (IF) connected to the control unit (MCU) for operating and / or receiving communication messages (RS). According to the invention, the power supply unit (NT) is connected to the main current paths (HB1, HB2, HB3, HBN) via auxiliary contacts (HK). The auxiliary contacts (HK) can be activated by the control unit (MCU).

Description

The invention relates to an electronic protective switching device for a low-voltage circuit according to the preamble of claim 1 and to a method according to the preamble of claim 13.

Circuit breaker means low-voltage circuit breakers. Low voltage means voltages up to 1000 volts alternating voltage or 1500 volts direct voltage. With low voltage are meant special voltages that are greater than the low voltage with values of 50 volts alternating voltage or 120 volts direct voltage.

• -Leistungsschalter, wie Kompaktleistungsschalter / Moulded Case Circuit Breaker bzw. Luftleistungsschalter / Air Circuit Breaker;
• -Fehlerstromschutzschalter, insbesondere netzspannungsabhängige Fehlerstromschutzschalter;
• -Brandschutzschalter / Fehlerlichtbogenschutzschalter / Arc Fault Detection Devices;
• -Leitungsschutzschalter, insbesondere elektronische Leitungsschutzschalter;
• -kombinierte Schutzschaltgeräte, wie z.B. ein Leistungsschalter mit Fehlerstromschutzfunktionalität, ein Fehlerstromschutzschalter mit Brandschutzschalterfunktionalität, ein kombinierter Leitungsschutz-, Fehlerstromschutz- und Brandschutzschalter, etc.;

gemeint.With circuit breakers are for example

• Circuit breakers, such as molded case circuit breakers or air circuit breakers;
• - Residual current circuit breakers, in particular mains voltage-dependent residual current circuit breakers;
• -Fire Protector / Arc Fault Detection Devices / Arc Fault Detection Devices;
• -Line circuit breakers, in particular electronic circuit breakers;
• -combined protective switching devices, such as a circuit breaker with residual current protection functionality, a residual current circuit breaker with fire protection switch functionality, a combined line protection, residual current protection and fire protection switch, etc .;

meant.

An electronic circuit breaker is a circuit breaker with an (integrated) power supply unit. The power pack is used to supply power to the protective functions.

Circuit breakers are circuit breakers that function similarly to a fuse. Circuit breakers monitor the current flowing through them by means of a conductor and interrupt the electrical current or energy flow to an energy sink or a consumer, which is referred to as tripping when protective parameters, such as current limit values or current-time limit values, ie when a current value for a certain period of time present, be exceeded. The set current limit values or current time span limit values are corresponding triggering reasons. The interruption takes place, for example, through contacts of the circuit breaker that are opened.

In particular for low-voltage circuits, systems or networks, there are different types of circuit breakers depending on the level of the intended electrical current in the electrical circuit. With circuit breakers in the sense of the invention are meant, in particular, switches as used in low-voltage systems for currents, in particular rated currents or maximum currents, of 63 to 6300 amperes. Closed circuit breakers for currents from 63 to 1600 amperes, in particular from 125 to 630 or 1200 amperes, are used more specifically. Open circuit breakers are used in particular for currents from 630 to 6300 amperes, more particularly from 1200 to 6300 amperes.
Open circuit breakers are also known as air circuit breakers, ACB for short, and closed circuit breakers as molded case circuit breakers or molded case circuit breakers, MCCB for short.

With circuit breakers in the sense of the invention, circuit breakers with an electronic trip unit serving as a control unit, also referred to as an electronic trip unit, or ETU for short, are meant.

If the current flow is too high, circuit breakers interrupt the circuit according to their protection parameters or response values. The protection parameters or response values are essentially the level of the current and the time after which the circuit should be interrupted if the current flow is “high”. In contrast to a fuse, these protection parameters or response values can be set in a circuit breaker, for example by means of the electronic trip unit. This is usually accessible via the front of the circuit breaker. The protection parameters can be set or parameterized here.

The units, in particular the electronic trip unit (ETU), but also other functional electronics of a protective switching device, such as a low-voltage circuit breaker, require an energy supply by means of a power pack for operation. This is usually made available by energy converters of the low-voltage circuit breaker, which are fed by means of the conductors or busbars passed through the low-voltage circuit breaker. This is also referred to as the internal supply of the protective switching device.

Circuit breakers according to the prior art are known from the following patent applications: DE 10 2014 217 292 A1 ; DE 10 2014 217 332 A1 ; DE 10 2015 217 108 A1 ; DE 10 2014 218 831 A1 ; DE 10 2014 218 910 A1 ; DE 10 2016 201 651 A1 ; DE 10 2015 226 475 A1 ; DE 10 2015 216 981 A1 ; DE 10 2016 202 827 A1 ; DE 10 2016 201 659 A1 ; DE 10 2015 210 479 A1 ; DE 10 2014 224 173 A1 ; DE 10 2015 216 023 A1 ; DE 10 2016 217 425 A1 ; DE 10 2016 205 196 A1 ; DE 10 2016 221 093 A1 ; DE 10 2017 211 900 A1 ; DE 10 2017 201 239 A1 ; DE 10 2017 205 003 A1 ; DE 10 2017 205 004 A1 ; DE 10 2017 212 477 A1 ; DE 10 2017 214 903 A1 ; DE 10 2017 214 907 A1 ; DE 10 2017 215 820 A1 .

A line circuit breaker according to the prior art is known from the following patent application: DE 10 2014 218 659 A1 .

Residual current circuit breakers according to the prior art are known from the following patent applications: DE 10 2013 219 292 A1 ; DE 10 2015 224 890 A1 ; DE 10 2015 225 423 A1 ; DE 10 2015 225 910 A1 ; DE 10 2015 218 911 A1 ; DE 10 2015 215 456 A1 ; DE 10 2016 213 875 A1 ; DE 10 2016 205 101 A1 ; DE 10 2017 217 040 A1 ; DE 10 2017 217 267 A1 ; DE 10 2017 217 411 A1 ; DE 10 2018 200 714 A1 .

Fire protection switches or arc fault protection switches according to the prior art are known from the following patent applications: DE 10 2013 219 289 A1 ; DE 10 2015 224 807 A1 ; DE 10 2015 207 444 A1 ; DE 10 2015 218 914 A1 ; DE 10 2017 211 121 A1 .

Combined residual current and fire protection switches according to the state of the art are known from the following patent applications: DE 10 2016 218 960 A1 ; DE 10 2016 223 264 A1 .

In accordance with regulations, e.g. according to DGUV-3 (German Association for Accident Prevention), systems must be subjected to an insulation test when they are started up for the first time and at regular intervals. Circuit breakers with electronics, which are connected to the main current paths via an integrated power supply unit, can generally also be operated with the supply lines fed in on both sides. If the protective switching device is switched off via an integrated contact system, depending on the feed direction, the power supply unit may still be supplied and thus live even when the protective switching device is switched off.
If an insulation test is then carried out, the problem arises via the active power supply unit and / or the intermediate input protective circuit (protection against overvoltage and current peaks) that the insulation test is recognized as faulty.

The device then usually has to be manually disconnected and checked, which means effort. In some cases, the electronics can even be damaged.

To avoid this, the feed direction is often fixed or the devices must be disconnected for the test, according to the state of the art.

The object of the present invention is to improve, in particular to facilitate, an insulation test of electronic protective switching devices in a low-voltage circuit.

This object is achieved by a protective switching device with the features of patent claim 1 or a method with the features of patent claim 13.

• - erste Anschlüsse für den Niederspannungsstromkreis, die über Hauptstrombahnen mit zweiten Anschlüssen für den Niederspannungsstromkreis verbunden sind;
• - eine Auslöseeinheit mit Kontaktsystem, das die Hauptstrombahnen unterbrechen kann, um eine Unterbrechung des Niederspannungsstromkreises zu bewirken;
• - eine Sensoreinheit, die mindestens eine elektronische Größe der Hauptstrombahnen bzw. des Niederspannungsstromkreises erfasst;
• - eine Steuereinheit, die mit der Sensoreinheit und der Auslöseeinheit verbunden ist und bei Überschreitung mindestens eines Grenzwertes der elektronische Größe eine Unterbrechung der Hauptstrombahnen mittels des Kontaktsystems bewirkt;
• - ein Netzteil, das mit der Steuerungseinheit und den Hauptstrombahnen verbunden ist, zur Energieversorgung der Steuereinheit;
• - eine mit der Steuereinheit verbundene Schnittstelle, zur Bedienung oder/und zum Empfang von Kommunikationsnachrichten; wobei das Schutzschaltgerät erfindungsgemäß dadurch gekennzeichnet ist,

dass das Netzteil über Hilfskontakte mit den Hauptstrombahnen verbunden ist,
dass die Hilfskontakte durch die Steuereinheit aktivierbar sind. Dies hat den Vorteil, dass für eine Isolationsprüfung das Netzteil durch die Hilfskontakte von den Hauptstrombahnen getrennt ist, wodurch eine ordnungsgemäße Isolationsprüfung ermöglicht wird, insbesondere unabhängig von der Einspeiserichtung des Schutzschaltgerätes.According to the invention, an electronic protective switching device for a low-voltage circuit is proposed, having:

• - First connections for the low-voltage circuit, which are connected via main current paths to second connections for the low-voltage circuit;
• - A trip unit with a contact system, which can interrupt the main current paths in order to cause an interruption of the low-voltage circuit;
• - A sensor unit that detects at least one electronic variable of the main current paths or the low-voltage circuit;
• a control unit which is connected to the sensor unit and the trigger unit and causes the main current paths to be interrupted by means of the contact system when at least one limit value of the electronic variable is exceeded;
• - A power supply unit, which is connected to the control unit and the main current paths, for supplying energy to the control unit;
• an interface connected to the control unit, for operating and / or receiving communication messages; wherein the protective switching device is characterized according to the invention

that the power supply unit is connected to the main current paths via auxiliary contacts,
that the auxiliary contacts can be activated by the control unit. This has the advantage that, for an insulation test, the power pack is separated from the main current paths by the auxiliary contacts, which enables a proper insulation test, in particular regardless of the direction in which the protective switching device is fed.

Advantageous embodiments of the invention are specified in the subclaims.

In an advantageous embodiment of the invention, the auxiliary contacts are part of an electromechanical switching element that is connected to the control unit.
This has the particular advantage that there is a simple, controllable solution for the auxiliary contacts.

In an advantageous embodiment of the invention, the power supply unit or the control unit has an energy store. This has the particular advantage that it is possible to switch off and / or switch on the power supply unit even when the main current paths are not carrying any electrical energy.

In an advantageous embodiment of the invention, a connection for an external power supply is provided.
This has the particular advantage that there is a further possibility for disconnecting and / or connecting the power supply unit when the main current paths do not carry any electrical energy.

In an advantageous embodiment of the invention, the control unit is designed in such a way that when an insulation test signal is present from the interface, the auxiliary contacts are activated, so that the power supply unit is separated from the main current paths.
This has the particular advantage that it enables the insulation test mode to be activated locally and / or remotely.

In an advantageous embodiment of the invention, the main current paths are interrupted by means of the trip unit before the auxiliary contacts are activated.
This has the particular advantage that the insulation test is carried out in a defined state of the switch with open contacts.

In an advantageous embodiment of the invention, the separation takes place for a first period of time. After the first period of time has elapsed, the power pack is reconnected to the main current paths.
This has the particular advantage that the insulation test is activated for a specific (first) period and the protective switching device automatically switches back to the normal operating mode / automatically resumes its protective function.

In an advantageous embodiment of the invention, the first time span can be set, in particular by means of the interface.
This has the particular advantage that there is an adjustable time span for the insulation test that is adapted to the local conditions.

In an advantageous embodiment of the invention, the power supply unit is reconnected to the main current paths by means of an operating command and / or a communication message via the interface and the control unit.
This has the particular advantage that an insulation test can be switched on and off again.

In an advantageous embodiment of the invention, the energy store is connected to the electromechanical switching element via a switching contact of the electromechanical switching element. Such that when the electromechanical switching element is activated, energy can be supplied via the switching contact of the electromechanical switching element.

This has the particular advantage that there is a particularly simple implementation for self-holding of the electromechanical switching element, and the first time span can be determined using the amount of energy available from the energy store.

In an advantageous embodiment of the invention, the energy store is connected to an energy supply line between the power supply unit and the control unit. In particular, in such a way that the energy store can be charged when the power supply unit is activated, or the control unit can be supplied with energy from the energy store when the power supply unit is deactivated.
This has the particular advantage that the control unit continues to be supplied with energy during the insulation test and is therefore still available or can carry out further functions.

In an advantageous embodiment of the invention, the energy store is connected to an energy supply line between the power supply unit and the control unit via a contact of the control unit. In particular in such a way that the energy store can be charged when the contact is closed and the power supply unit is activated, or the control unit can (optionally) be supplied with energy from the energy store when the contact is closed and the power supply unit is deactivated.
This has the particular advantage that it enables individual charging and supply management.

An additional advantageous method for an electronic protective switching device is also claimed.

All configurations, both in a dependent form referring back to patent claim 1 as well as referring back only to individual features or feature combinations of patent claims, bring about an improvement electronic protective switching device, in particular for an insulation test or measurement.

The described properties, features and advantages of this invention and the manner in which they are achieved will become clearer and more clearly understandable in connection with the following description of the exemplary embodiments, which are explained in more detail in connection with the drawing.

• 1 ein schematisches Blockschaltbild eines erfindungsgemäßen elektronischen Schutzschaltgerätes;
• 2 eine spezifische erste Ausgestaltung zu 1;
• 3 eine spezifische zweite Ausgestaltung zu 1.

In the accompanying drawing shows:

• 1 a schematic block diagram of an electronic protective switching device according to the invention;
• 2 a specific first embodiment 1 ;
• 3 a specific second embodiment 1 .

• - erste Anschlüsse LE1, LE2, LE3, LEN für den Niederspannungsstromkreis, beispielsweise an einem Gehäuse GEH, die über Hauptstrombahnen HB1, HB2, HB3, HBN mit zweiten Anschlüssen LA1, LA2, LA3, LAN für den Niederspannungsstromkreis, beispielsweise am Gehäuse GEH, verbunden sind;
• - eine Auslöseeinheit AE mit Kontaktsystem KS, das die Hauptstrombahnen HB1, HB2, HB3, HBN unterbrechen kann, um eine Unterbrechung des Niederspannungsstromkreises zu bewirken;
• - eine Sensoreinheit SE, die mindestens eine elektronische Größe der Hauptstrombahnen HB1, HB2, HB3, HBN bzw. mindestens einer Hauptstrombahn bzw. des Niederspannungsstromkreises erfasst;
• - eine Steuereinheit MCU, die mit der Sensoreinheit SE und der Auslöseeinheit AE verbunden ist und bei Überschreitung mindestens eines Grenzwertes der elektronische Größe eine Unterbrechung der Hauptstrombahnen HB1, HB2, HB3, HBN mittels des Kontaktsystems KS bewirkt;
• - ein Netzteil NT, das mit der Steuerungseinheit MCU und den Hauptstrombahnen HB1, HB2, HB3, HBN verbunden ist, zur Energieversorgung der Steuereinheit MCU;
• - eine mit der Steuereinheit MCU verbundene Schnittstelle IF, zur Bedienung des Schutzschaltgerätes am Schutzschaltgerät oder/und zum Empfang von Kommunikationsnachrichten, beispielsweise durch eine externe Steuerung bzw. ein externes Kommunikationsgerät bzw. (Isolationsprüfungs-)Gerät.

Das Netzteil NT ist über Hilfskontakte HK mit den Hauptstrombahnen HB1, HB2, HB3, HBN verbunden. Im Beispiel gemäß 1 sind nur die Phasenleiter L1, L2, L3 über Hilfskontakte HK mit dem Netzteil verbunden. Der Neutralleiter N ist ohne Hilfskontakt mit dem Netzteil verbunden. Alternativ kann der Neutralleiter N über einen Hilfskontakt HK mit dem Netzteil NT verbunden sein, um eine vollständige galvanische Trennung zu erreichen.
Die Hilfskontakte HK sind Teil eines elektromechanischen Schaltelementes REL, dass mit der Steuereinheit MCU verbunden ist. Das elektromechanische Schaltelement REL kann beispielsweise ein Relais sein. Die Hilfskontakte HK sind über das elektromechanische Schaltelement REL durch die Steuereinheit MCU aktivierbar.
Die Hilfskontakte HK können Öffner sein. D.h. im Grundzustand (spannungsloser Zustand des elektromechanischen Schaltelementes REL) sind die Hilfskontakte geschlossen.
Das Schutzschaltgerät weist einen Energiespeicher ES auf. Im Beispiel ist das Netzteil NT mit dem Energiespeicher ES verbunden bzw. das Netzteil NT weist den Energiespeicher ES auf. 1 shows an electronic circuit breaker SG for a low-voltage circuit, in the example a three-phase AC circuit with three phase conductors L1 , L2 , L3 and a neutral conductor N, having:

• - first connections LE1 , LE2 , LE3 , LEN for the low-voltage circuit, for example on a housing GO running across main power lines HB1 , HB2 , HB3 , HBN with second connections LA1 , LA2 , LA3 , LAN for the low-voltage circuit, for example on the housing GO , are connected;
• - a trip unit AE with contact system KS , which is the main power lines HB1 , HB2 , HB3 , HBN can interrupt to cause an interruption of the low-voltage circuit;
• - A sensor unit SE, the at least one electronic variable of the main current paths HB1 , HB2 , HB3 , HBN or at least one main current path or the low-voltage circuit detected;
• - A control unit MCU, which is connected to the sensor unit SE and the trigger unit AE and an interruption of the main current paths when at least one limit value of the electronic variable is exceeded HB1 , HB2 , HB3 , HBN by means of the contact system KS causes;
• - a power supply unit NT that connects to the control unit MCU and the main current paths HB1 , HB2 , HB3 , HBN is connected to supply power to the control unit MCU;
• - An interface IF connected to the control unit MCU, for operating the protective switching device on the protective switching device and / or for receiving communication messages, for example by an external controller or an external communication device or (insulation testing) device.

The NT power pack is connected to the main current paths via auxiliary contacts HK HB1 , HB2 , HB3 , HBN connected. In the example according to 1 are just the phase conductors L1 , L2 , L3 connected to the power pack via auxiliary contacts HK. The neutral conductor N is connected to the power supply unit without an auxiliary contact. Alternatively, the neutral conductor N can be connected to the power supply unit NT via an auxiliary contact HK in order to achieve complete galvanic separation.
The auxiliary contacts HK are part of an electromechanical switching element REL that is connected to the control unit MCU. The electromechanical switching element REL can for example be a relay. The auxiliary contacts HK are via the electromechanical switching element REL can be activated by the control unit MCU.
The auxiliary contacts HK can be NC contacts. Ie in the basic state (de-energized state of the electromechanical switching element REL ) the auxiliary contacts are closed.
The protective switching device has an energy store ES. In the example, the power supply unit NT is connected to the energy store ES or the power supply unit NT has the energy store ES.

Alternatively or in addition to the energy store ES, a connection for an external energy supply can be provided.

According to the invention, the control unit is designed in such a way that when an insulation test signal is present from the interface IF, the auxiliary contacts HK are activated so that the power supply unit NT is disconnected from the main current paths, at least in terms of voltage HB1 , HB2 , HB3 (and possibly HBN ) is separated.

The main current paths may be interrupted before the auxiliary contacts HK are activated HB1 , HB2 , HB3 , HBN by means of the release unit AE or its contact system KS respectively. For example, the insulation test signal first interrupts the main current paths HB1 , HB2 , HB3 , HBN and then activates the auxiliary contacts HK.

The separation can take place for a first period of time and after the first period of time has elapsed, the power pack is reconnected to the main current paths, whereby the protective switching device is automatically switched from test mode to protection mode.
The first time span can be adjustable, in particular by means of the interface IF.

Alternatively or additionally, the power supply unit NT can be reconnected to the main current paths by means of an operating command and / or a communication message via the interface IF and the control unit MCU. This means that the (insulation) test mode can be switched on and / or off specifically.

The circuit breaker SG can be a housing GO have, in which the units mentioned are included, such as in 1 shown.

According to the invention, the power supply unit is switched off by an electrical, electronic or electromechanical switch. This enables an active and at the same time monitored sequence of actions (processes). For recurring insulation tests, this results in an automated, elegant process with various monitoring options.

The insulation test or insulation measurement function is initiated via the interface IF, e.g. by an external communication message or communication telegram or local triggering of the function via the existing operating elements of the interface IF, such as display, buttons, auxiliary buttons, etc. logged by the control unit MCU.

The protective switching device SG triggered, ie an interruption of the main current paths HB1 , HB2 , HB3 , HBN so that it is in a safe state before the insulation measurement is activated / started. Alternatively, the insulation test function can only be used when the main current paths are interrupted HB1 , HB2 , HB3 , HBN / open contact system KS activate.

Before tripping, the protective switching device can be shut down in a targeted manner, for example in the case of circuit breakers such as molded case circuit breakers or air circuit breakers, in order to avoid disconnection at high load currents and thus not unnecessarily load the contact system.

If the power supply unit continues to be supplied with energy after the main current paths have been interrupted (switching off the contact system), depending on the direction of feed into the protective switching device, the process of disconnecting the power supply unit can now take place.

An internal energy store ES can be used for this. This can, for example, be a battery, accumulator, capacitor with high capacity (super capacitor, gold cap), etc. Alternatively or in parallel, an external backup voltage can be provided. Such as an external protective extra-low voltage or a voltage via the IF interface.
For example, the control unit MCU switches to an energy-saving mode and then the targeted shutdown takes place. For example, before the shutdown, a message can be sent via the interface IF to a central data node (not shown) (master control SPC, PC, control center, etc.).

The insulation can then be measured (manually) by a qualified electrician.

Alternatively, the insulation measurement can be carried out automatically. According to DGUV-3, permanent insulation monitoring has been permitted for some time, for example using a residual current monitor (RCM for short) or an insulation monitor. This means that recurring measurements can be carried out automatically with a high degree of accuracy and time savings. In addition, these can be logged.

1. a) Aktivierung durch Einschalten des Schutzschaltgeräts, insbesondere falls (abh. von der Einspeiserichtung) das Kontaktsystem KS die Versorgung des Netzteils automatisch unterbrach;
2. b) Über eine voreingestellte Zeit am Schutzschaltgerät;
3. c) Über eine Unterspannungsüberwachung/Energieüberwachung, falls eine Hilfsenergie einer externen Energieversorgung entfällt/abfällt (Drahtbruch, Stecker abziehen, Akku leer);
4. d) Über einen Kommunikationsbefehl über die Schnittstelle IF, z.B. von einer Leitstelle;
5. e) Über eine manuelle Aktivierung (Schalter/Display) am Gerät selbst;
6. f) Über einen Hilfskontakt am Gerät (Fernsteuerung).

The separation can take place for a first period of time and after the first period of time has elapsed, the power pack is reconnected to the main current paths, whereby the protective switching device is automatically switched from test mode to protection mode. Alternatively or additionally, the power supply unit NT can be reconnected to the main current paths by means of an operating command and / or a communication message via the interface IF and the control unit MCU. This means that the (insulation) test mode can be switched on and / or off specifically.
Switching on / off can be done by an event (event / control command), such as:

1. a) Activation by switching on the protective switching device, especially if (depending on the feed direction) the contact system KS automatically interrupted the power supply;
2. b) For a preset time on the circuit breaker;
3. c) Via an undervoltage monitoring / energy monitoring, if an auxiliary energy of an external energy supply is omitted / drops out (wire break, pull out plug, battery empty);
4. d) Via a communication command via the IF interface, for example from a control center;
5. e) Via manual activation (switch / display) on the device itself;
6. f) Via an auxiliary contact on the device (remote control).

After reconnecting the power supply unit, the MCU control unit carry out an internal self-test. The energy store ES can, for example, be charged again or further.

A logging of the insulation test, for example by the control unit MCU, can be completed. A final report can be sent to a central controller, for example via the IF interface.

The electromechanical switching element REL can be the following: electromechanical relays, reed relays, solid state relays, FET switches, thyristor / triac switches, hybrid switches, bimetal, polymer PTC thermistor switches, electrical drive that disconnects spring contacts, silicon semiconductors, MEMS - Micro-Electro-Mechanical-System . Furthermore, for example, a series connection of mini-switches with accommodation on an integrated circuit. With the series connection, a required insulation value (x kV withstand voltage and / or surge voltage) can be achieved.

• - Protokollierung in Event/Datenlogbuch;
• - Absetzen von Meldungen über Schnittstelle IF, z.B. zu zentraler Steuerung;
• - Setzen von Meldeausgängen (z.B. Alarmleitung), z.B. mittels bistabilen Relais.

In the event of a failure of the primary energy (power supply unit), the energy storage ES can be used to buffer the MCU control unit, whether by switching off the protective switching device, manual actuation, test button function or incorrect behavior (e.g. failure of components) so that these actions can be initiated, how:

• - Logging in event / data logbook;
• - Sending messages via the IF interface, eg to a central controller;
• - Setting of message outputs (eg alarm line), eg by means of bistable relays.

2 shows an exemplary specific first embodiment 1 . 2 shows the auxiliary contact HK, the electromechanical switching element REL , the power supply unit NT, the control unit MCU, the interface IF and the energy store ES according to 1 . Furthermore a voltage-time diagram in the lower part.
The control unit MCU has a contact KMCU which can be activated by the control unit MCU, in the example a normally open contact. The contact KMCU connects the energy store ES with the energy connection between the power supply unit NT and the control unit MCU, in the example the positive connection of the energy store ES with the positive line between the power supply unit NT and the control unit MCU.
The electromechanical switching element REL has a further switching contact SK in addition to the auxiliary contact HK.
The switching contact SK is also a normally open contact in the example and connects the energy store ES to the connection between the control unit MCU and the electromechanical switching element REL , In the example, the positive connection of the energy store ES is connected to the positive line between the MCU control unit and the electromechanical switching element via the switch contact SK REL connected.

The way it works is as follows. The control unit MCU activates the contact KMCU and the electromechanical switching element when an insulation test signal is present from the interface IF REL .
The control unit MCU receives energy from the energy store ES by means of the contact KMCU. The control unit can alternatively leave or open contact KMCU in order to save energy.
The electromechanical switching element REL on the one hand closes the switching contact SK, whereby it is supplied with energy from the energy store ES and holds itself, and on the other hand opens the auxiliary contact HK, so that the power pack is separated from the main current paths.

If the energy of the energy store ES is reduced (consumption by (control unit MCU and) electromechanical switching element REL ), and if the energy falls below a first energy threshold value, such as a first voltage threshold value, the electromechanical switching element falls REL off, ie the auxiliary contact HK closes, the power pack NT is supplied with energy and consequently the control unit MCU.

Due to the drop in the electromechanical switching element REL the switching contact SK opens, so that the electromechanical switching element REL is separated from the energy store ES.
The control unit MCU closes the contact KMCU or leaves the contact KMCU closed until the energy store ES is charged again.

This is indicated by the voltage-time diagram in the lower part, in which the voltage U is plotted on the vertical axis and the time t on the horizontal axis. The first time period t_on is the time of the interruption of the power supply unit from the main current paths, ie from the low-voltage circuit or network.
The first time span is determined by the energy storage capacity of the energy store ES and the energy requirement of the electromechanical switching element REL (possibly also the energy requirements of the MCU control unit).

3 FIG. 14 shows an exemplary specific second embodiment according to 2 , with the difference that the contact KMCU is not provided.
As a result, the control unit MCU is always connected to the energy store ES. As a result, the control unit MCU can still remain active, for example in an energy-saving mode. The control unit MCU can thus react to interactions, such as targeted, premature resetting to active operation, for example by means of an operating command and / or a communication message via the interface IF, such as a switch-on signal RS, such as shown in the lower part in the voltage-time diagram.

• - einfache Einbaumöglichkeit
• - Steuerungsmöglichkeit per Firmware
• - Vermeidung des Verlustes der Schutzfunktion bzw. Ausbau
• - Protokollierungsmöglichkeit im Gerät oder/und über Schnittstelle IF, beispielsweise in einer zentralen Einheit
• - Fernsteuerung über Signalkontakt oder Kommunikation
• - Automatisierung der wiederkehrenden Isolationsprüfungen für Anlagen mit notwendig hoher Verfügbarkeit
• - Verbesserung der funktionalen Sicherheit (Zustand jederzeit bekannt und protokolliert, gesteuert mit ggf. weiterführenden Sicherungsmaßnahmen, wie z.B. Alarmkontakt, etc.)
• - bei externer Stützspannung ergibt sich eine kompaktere Ausführungsmöglichkeit
• - elegante Lösung gerade auch für kompakte Schalt- und Kontrollgeräte wg. Minimalem Bauraum.

The invention has the advantage that an electrical, automated control for insulation testing is made possible, with the further advantages:

• - easy to install
• - Control option via firmware
• - Avoidance of the loss of the protective function or expansion
• - Logging option in the device and / or via interface IF, for example in a central unit
• - Remote control via signal contact or communication
• - Automation of the recurring insulation tests for systems with necessary high availability
• - Improvement of the functional safety (status known and logged at any time, controlled with any further safety measures, such as alarm contact, etc.)
• - With external backup voltage there is a more compact design option
• - elegant solution especially for compact switching and control devices wg. Minimal installation space.

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

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

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Claims (13)

Electronic protective switching device (SG) for a low-voltage circuit, comprising: - first connections (LE1, LE2, LE3, LEN) for the low-voltage circuit, which are connected via main current paths (HB1, HB2, HB3, HBN) to second connections (LA1, LA2, LA3, LAN ) are connected for the low voltage circuit; - A trip unit (AE) with contact system (KS), which can interrupt the main current paths (HB1, HB2, HB3, HBN) in order to cause an interruption of the low-voltage circuit; - A sensor unit (SE) which detects at least one electronic variable of the main current paths (HB1, HB2, HB3, HBN) or of the low-voltage circuit; - A control unit (MCU), which is connected to the sensor unit (SE) and the trigger unit (AE) and if at least one limit value of the electronic variable is exceeded, the main current paths (HB1, HB2, HB3, HBN) are interrupted by means of the contact system (KS) causes; - A power supply unit (NT), which is connected to the control unit (MCU) and the main current paths (HB1, HB2, HB3, HBN), for supplying energy to the control unit (MCU); - an interface (IF) connected to the control unit (MCU), for operating and / or receiving communication messages (RS); characterized in that the power supply unit (NT) is connected to the main current paths (HB1, HB2, HB3, HBN) via auxiliary contacts (HK), and that the auxiliary contacts (HK) can be activated by the control unit (MCU). Circuit breaker (SG) Claim 1 , characterized in that the auxiliary contacts (HK) are part of an electromechanical switching element (REL) that is connected to the control unit (MCU). Circuit breaker (SG) Claim 1 or 2 , characterized in that an energy store (ES) is provided which is at least partially connected in particular to the power supply unit (NT) and / or the control unit (MCU). Circuit breaker (SG) Claim 1 , 2 or 3 , characterized in that a connection for an external power supply is provided. Protective switching device (SG) according to one of the preceding claims, characterized in that the control unit (MCU) is designed in such a way that the auxiliary contacts (HK) are activated when an insulation test signal is present from the interface (IF), so that the power supply unit (NT) is separated from the main current paths (HB1, HB2, HB3). Circuit breaker (SG) Claim 5 , characterized in that before the auxiliary contacts (HK) are activated, the main current paths are interrupted by means of the trip unit (AE). Circuit breaker (SG) Claim 5 or 6th , characterized in that the separation takes place for a first period of time (t_on) and after the first period of time (t_on) the power supply unit (NT) is again connected to the main current paths (HB1, HB2, HB3, HBN). Circuit breaker (SG) Claim 7 , characterized in that the first time period (t_on) can be set, in particular by means of the interface (IF). Circuit breaker (SG) Claim 5 , 6th , 7th or 8th , characterized in that by means of an operating command and / or a communication message (RS) via the interface (IF) and the control unit (MCU), the power supply unit (NT) is reconnected to the main current paths (HB1, HB2, HB3, HBN). Protective switching device (SG) according to one of the preceding claims, characterized in that the energy store (ES) is connected to the electromechanical switching element (REL) via a switching contact (SK) of the electromechanical switching element (REL), so that when the electromechanical switching element (REL ) an energy supply can take place via the switching contact (SK) of the electromechanical switching element (REL). Protective switching device (SG) according to one of the preceding claims, characterized in that the energy store (ES) is connected to an energy supply line between the power supply unit (NT) and the control unit (MCU) so that the energy store can be charged when the power supply unit (NT) is activated or when the power supply unit (NT) is activated deactivated power supply unit (NT) the control unit (MCU) can be supplied with energy from the energy store (ES). Circuit breaker (SG) Claim 10 , characterized in that the energy store (ES) is connected via a contact (KMCU) of the control unit (MCU) to an energy supply line between the power supply unit (NT) and the control unit (MCU), so that the energy store is connected when the contact is closed and the power supply unit (NT) is activated is chargeable or when the contact is closed and the power supply unit (NT) is deactivated, the control unit (MCU) can be supplied with energy from the energy store (ES). Method for an electronic protective switching device (SG) for a low-voltage circuit, comprising: - first connections (LE1, LE2, LE3, LEN) for the low-voltage circuit, which are connected via main current paths (HB1, HB2, HB3, HBN) to second connections (LA1, LA2, LA3, LAN) for the low voltage circuit are connected; - A trip unit (AE) with contact system (KS), which can interrupt the main current paths (HB1, HB2, HB3, HBN) in order to cause an interruption of the low-voltage circuit; - A sensor unit (SE) which detects at least one electronic variable of the main current paths (HB1, HB2, HB3, HBN) or of the low-voltage circuit; - A control unit (MCU), which is connected to the sensor unit (SE) and the trigger unit (AE) and if at least one limit value of the electronic variable is exceeded, the main current paths (HB1, HB2, HB3, HBN) are interrupted by means of the contact system (KS) causes; - A power supply unit (NT), which is connected to the control unit (MCU) and the main current paths (HB1, HB2, HB3, HBN), for supplying energy to the control unit (MCU); - an interface (IF) connected to the control unit (MCU), for operating and / or receiving communication messages (RS); characterized in that the power supply unit (NT) is connected to the main current paths (HB1, HB2, HB3, HBN) via auxiliary contacts (HK), that the auxiliary contacts (HK) can be activated by the control unit (MCU), that the control unit (MCU) if there is an insulation test signal from the interface, activates the auxiliary contacts (HK) so that the power supply unit (NT) is separated from the main current paths (HB1, HB2, HB3, HBN).

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