EP0013320A1 - Electrical main line protection switch serving as group protection switch - Google Patents

Abstract

1. An electrical main line protection switch (62) serving as a group protection switch, for the protection of an electrical installation consisting of a plurality of circuits, the main line protection switch (62) being selective with respect to the line protection switches (34, 36, 38) associated with the consumer devices (28, 30, 32), characterised in that a tripping device (42), which acts upon a latch (56), is in series with the electromagnetic percussion armature system (44) of the main line protection switch (62), which system (44) serves only for the temporary opening of the contact lever (46), and the tripping device (42) is so designed that it only trips when a particular value of Intg i**2 dt has been reached.

Description

The invention relates to an electrical installation device according to the preamble of claim 1.

• Sofern in dem Bereich zwischen dem Hauptleitungsschutzschalter und dem Verbraucher bzw. im Verbraucher ein Kurzschlußstrom oder überstrom entsteht, muß der Leitungsschutzschalter ansprechen, ohne daß der Hauptleitungsschutzschalter auslöst, damit nicht die anderen, nicht vom Kurzschluß betroffenen Stromkreise mitabgeschaltet werden. Sofern ein Kurzschluß hinter dem Hauptleitungsschutzschalter und vor dem den Verbrauchern zugeordneten Schutzschaltern entsteht, muß zwangsläufig der Hau^ptleitungsschutzschalter ausschalten. Man sagt, daß der Hauptleitungsschutzschalter gegenüber den den Verbrauchern zugeordneten Leitungsschutzschaltern selektiv sein muß.

In house installation systems, in particular in residential buildings with several residential units, the consumer groups in the individual residential units are each protected by means of their own circuit breaker or residual current circuit breaker. These switches, which are assigned to the consumers, are generally preceded by a main circuit breaker which serves to protect the entire installation system. The electrical assignment of the consumer circuit breaker to the main circuit breaker is carried out in the following way:

• If there is a short-circuit current or overcurrent in the area between the main circuit breaker and the consumer or in the consumer, the circuit breaker must respond without the main circuit breaker tripping, so that the other circuits not affected by the short circuit are not also switched off. If a short circuit occurs in front of the back of the main circuit breaker and the loads associated circuit breakers, the Hau must turn ^p tleitungsschutzschalter necessarily. It is said that the main circuit breaker must be selective with respect to the circuit breakers associated with the consumers.

DE-OS 2 525 192 describes a selective protection device in which a cascade is shown, in whose individual lines circuit breakers or residual current circuit breakers are installed, to which counting devices are assigned. This counting device counts the successive opening and closing sequences of the contacts, and after a predetermined number of sequences triggering can be caused. The counting devices are designed so that they open and close more frequently, the closer the individual switch in the hierarchy is to the feed point.

Such counting devices are relatively complicated. In addition, extensive line installations for the control of the individual auto switches must be arranged.

It is also possible to choose different response values for the magnetic releases so that the switch closer to the feed point is adapted to a higher short-circuit current. In the case of extremely high short-circuit currents, however, the switches arranged in series are triggered; selectivity is only guaranteed in a relatively small area.

The object of the invention is to provide an installation device serving as a group switch, in particular a circuit breaker of the type mentioned at the outset, so that on the one hand it supports the short-circuit shutdown of a downstream circuit breaker, but remains on after the short-circuiting process has ended.

This object is achieved in that in series with the electromagnetic anchoring system, which is only used for the temporary opening of the contact lever, acting on a switching lock, preferably thermal trigger is connected, which is designed so that it only after reaching a certain J i ² dt - value triggers.

The invention is mainly applied to circuit breakers; it can of course also be used for residual current circuit breakers, motor circuit breakers and the like. However, it should essentially be explained using circuit breakers in a house installation.

A particular advantage of the invention is that you can practically use a modified circuit breaker for the main circuit breaker or for the group terminal. While the known miniature circuit breakers are generally constructed so that both the thermal release and the magnetic release act together on a switch lock, while the magnetic release also acts directly on the contact lever in the event of a short circuit, one can in the embodiment according to the invention remove the impact pin of the impact anchor of a normal circuit breaker that acts on the switch lock; one then only has to adapt the thermal release in a corresponding manner to the tasks.

If a thermal release is used, then a thermal bimetal is advantageously used.

There is also the possibility of assigning a hinged armature system to the magnetic impact armature system, the hinged armature of which actuates when a certain overcurrent or short-circuit current occurs and acts on the switching mechanism to trigger it.

Such a hinged armature system is formed in that at least part of the yoke of the electromagnetic impact armature system is formed by a magnetic plate which in the idle state attracts the hinged armature and that the plate is designed such that in the event of an overcurrent or short-circuit current, the magnetic attraction of the plate is canceled so that the switch lock is released.

The individual systems can be matched to one another in such a way that the electromagnetic impact armature system for a short-circuit current of, for example, greater than approximately 500 A, the thermal release for a current of, for example, greater than 3000 A with a tripping time of approximately 10 ms, and the hinged armature system are designed for an overcurrent or short-circuit current greater than 5000 A.

The thermal release, which can also be an electronic release, is set so that it only triggers at or above a thermal effective variable J i ² dt which results in the case of short-circuits with 3000 A in the case of circuit breakers. As mentioned, the temporary contact opening by the impact anchor is used to support a shutdown process a downstream circuit breaker designed so that it starts at currents above 5000 A, for example. The response time of the thermal release is expediently greater than 10 ms, which, as also mentioned above, can best be achieved by means of a bimetal. With the aid of the drawing, some exemplary embodiments as well as further improvements and further advantages will be explained in more detail.

• Fig. 1 ein Prinzipschaltbild einer Niederspannungs-installation,
• Fig. 2 ein Prinzipschaltbild einer Niederspannungshausinstallation mit einem erfindungsgemäßen Überlasthauptschalter,
• Fig. 3 Prinzipskizzen für einen normalen Sicherun^gs-und 4 automat und einen erfindungsgemäßen Überlastschalter und
• Fig. 5 eine besondere Ausgestaltung einer Auslöse- bzw. Kontakthebelöffnungseinrichtung, in der die Erfindung realisiert ist.

It shows

• 1 is a schematic diagram of a low voltage installation,
• 2 shows a basic circuit diagram of a low-voltage house installation with an overload main switch according to the invention,
• Fig. 3 are schematic diagrams for a normal Sicherun s and ^g 4 automat and a circuit breaker according to the invention and
• Fig. 5 shows a special embodiment of a release or contact lever opening device in which the invention is implemented.

1 shows a low-voltage installation in the form of a cascade, which has a transformer 14 at its input between the connection points 10 and 12, to which a line section L ₁ is then connected. At the end of the line section L ₁ there is a connection 16 to which a main fuse 17, for example an NH fuse, connects. This NH fuse 17 has an output 18, to which a line piece L ₂ connects, which in turn ends in a connection point 20. At the connection point 20 there is a main distribution, such that the line L ₁ plus L _{2 is} distributed in branch lines L ₃ , L ₄ ... etc.

• Hinter dem Anschlußpunkt bzw. Verzweigungspunkt 20 befindet sich eine Vorsicherung oder Hausanschlußsicherung 21, die im allgemeinen als Schmelzsicherung ausgebildet ist. Mit der Anschlußklemme 22 der Schmelzsicherung 21 ist ein Leitungszug L₄ verbunden, der auf einen Abzweigpunkt 26 geht, an dem sich Leitungszüge L₅, L₆, L₇ ... verzweigen, die jeweils zu einzelnen Verbrauchern 28, 30 und 32 ... führen. Jeder dieser Verbraucher 28 ... ist mittels eines Leitungsschutzschalters 34, 36 und 38 .... abgesichert, der ein normaler, handelsüblicher Leitungsschutzschalter mit Überstrom- und Kurzschlußstromauslösun^g ist, der selbstverständlich auch als Fehlerstromschutzschalter ausgebildet sein kann. Ein solcher handelsüblicher Leitungsschutzschalter ist in der Fig. 3 dargestellt. Man erkennt - schematisch und blockartig - einen in den Hauptstrompfad 40 eingesetzten thermischen Auslöser 42 und einen magnetischen Auslöser 44, der an einem drehbar aufgelagerten Kontakthebel 46 angeschlossen ist. Der Kontakthebel bildet mit einem Festkontakt 48 eine Trennstelle 50, der ein Lichtbogenlöschblechpaket 52 zugeordnet ist. Man erkennt, daß der thermische Auslöser, der im Normalfall als Bimetall ausgebildet.ist, über eine Wirklinie 54 auf ein Schaltschloß 56 einwirkt, ebenso wie der magnetische Auslöser, der über die Wirklinie 58 auf das Schaltschloß 56 wirkt. Der magnetische Auslöser 44, der einen Schlaganker aufweist, öffnet im Falle eines Kurzschlußes über die Wirklinie 60 die Trennstelle 50 und entklinkt gleichzeitig auch das Schaltschloß 56, so daß die Ausschaltung bleibend ist. Ein derartiger Leitungsschutzschalter ist beispielsweise der DE-AS 11 92 730 beschrieben.

Now consider the line L ₃ :

• Behind the connection point or branch point 20 there is a back-up fuse or house connection fuse 21, which is generally designed as a fuse. With the connecting terminal 22 of the fuse 21, a cable line L _{4 is} connected, which goes to a branch point 26, at which line lines L ₅ , L ₆ , L ₇ ... branch, each to individual consumers 28, 30 and 32 .. . to lead. Each of these load 28 ... is protected by a circuit breaker 34, 36 and 38 ...., ^g is a normal, commercially available circuit breaker with overcurrent and Kurzschlußstromauslösun, which can of course also be designed as a fault-current circuit breaker. Such a commercially available circuit breaker is shown in FIG. 3. One recognizes - schematically and in block form - a thermal release 42 inserted in the main current path 40 and a magnetic release 44 which is connected to a rotatably mounted contact lever 46. The contact lever forms a separation point 50 with a fixed contact 48, which is assigned an arc-quenching plate packet 52. It can be seen that the thermal release, which is normally designed as a bimetal, acts on a switching lock 56 via an action line 54, as does the magnetic one Trigger that acts on the switching mechanism 56 via the line of action 58. The magnetic release 44, which has an impact armature, opens the disconnection point 50 in the event of a short circuit via the line of action 60 and at the same time unlatches the switch lock 56, so that the switch-off is permanent. Such a circuit breaker is described for example in DE-AS 11 92 730.

It should be noted that both the thermal release 42 and the magnetic release 44 act together on the switch lock, the magnetic release also still acting on the contact lever 46 in the event of a short circuit.

The fuse 21 is selective with respect to the circuit breakers, since it is matched to the circuit breaker 34 bus 38 in a corresponding manner and responds to a higher short circuit than this.

According to the fuse 21 is to be replaced by a group switch. This results in the low-voltage house installation shown schematically in FIG. 2 with an overload main switch. This main switch is used instead of the fuse 21 between the line pieces L ₃ and L ₄ and has the reference number 62 in FIG. 2. In the rest of the illustration, nothing has changed in this respect.

Such a switch can be used as switch 62, which is shown schematically in FIG. 4. This switch has a thermal release 42 and a magnetic impact anchor system 44, of which only the thermal release acts via the operative connection 54 on the switching mechanism 56, which brings the contact lever into the open position and holds it there. The Magnetic impact anchor system acts on the contact lever 46 via the operative connection 6 ₀ , only to open it briefly or briefly. An active connection between the impact anchor system 44 and the switch lock 56 is no longer present.

The thermal release is then suitably adapted to the expected short-circuit current and in such a way that it triggers at a short-circuit current of 3000 A, while the electromagnetic impact armature system starts at 500 A with the temporary opening of the contact lever 46.

So that the switch triggers above a certain limit of 5000 A, for example, an arrangement according to the Fi ^g . 5 used. You can see the contact lever 46 with the movable contact 47, which cooperates with the fixed contact 48, such that an arc is drawn between the two during a switch-off process, which runs into the arc quenching plates 52. The temporary opening of the movable contact 46 takes place via an impact armature system 44 which has a coil 70 which drives a movable magnet armature which is pressed away from the fixed magnetic core 76 under the pressure of a spring 74. The Schlla ^g anchor system also has an impact pin 78 which is pressed to the right by the magnet armature 72 in the event of a switch-off movement and opens the movable contact 46 against the pressure of a spring 80. A magnetic plate 82 (drawn in thick lines) is also attached to the impact anchor system, which interacts with a hinged anchor 84, which hinged anchor can strike clockwise in the direction of the arrow F against a lever 86 which opens a latching point (not shown further) in the switching mechanism 56 and thereby pushing the contact lever into the off position.

With an overcurrent of about 5000 A, the magnetic circuit becomes like this influences that the magnetic plate 82 is demagnetized, so that the pulling force on the hinged armature 84 is reduced so that the hinged armature folds up in the direction of arrow F and actuates the lever 86.

• a) vorübergehende öffnung des Kontaktes bei 47 bei Strömen über 5000 A,
• b) thermische Auslösung bei einem Wert i² dt entsprechend einer Schmelzsicherungskennlinie, beispielsweise bei 3000 A und
• c) sofortige Auslösung bei einem bestimmten I_D-Scheitelwert von 5000 A.

The thermal trigger, which is not shown in FIG. 5 for the sake of clarity, triggers at a ∫ i2 dt value; it lies in series with the coil, so that the switch or the arrangement according to FIG. 5 responds to a total of three current criteria

• a) temporary opening of the contact at 47 at currents above 5000 A,
• b) thermal tripping at a value i ² dt corresponding to a fuse characteristic, for example at 3000 A and
• c) immediate triggering at a certain I _D peak value of 5000 A.

Claims (5)

1. As a group protection switch serving electrical installation device, in particular main circuit breaker for protecting an electrical system consisting of several circuits, the main switch must be selective with respect to the circuit breakers assigned to the consumers, characterized in that in series with the electromagnetic anchor system (44), which only For the temporary opening of the contact lever (46), a preferably thermal release acting on a switching lock is used, which is designed such that it only triggers after a certain ji ² dt value has been reached. 2. Installation device according to claim 1, characterized in that the thermal release is provided with a bimetal. 3. _I nstallationsgerät according to claim 1, characterized in that the magnetic impact anchor system (44) is assigned a hinged armature system, the hinged armature responds when a short-circuit current occurs and acts on the switch lock. 4. Installation device according to claim 3, characterized in that at least part of the yoke of the magnetic impact anchor system (44) is formed by a magnetic plate (82) which attracts the hinged anchor (84) of the hinged anchor system in the idle state, and in that the plate is formed or is dimensioned that in the event of an overcurrent their magnetic attraction is canceled and the switch lock is released. 5. Installation device according to one of the preceding claims, characterized in that the electromagnetic impact anchor system (44) to a short-circuit current of, for example, greater than about 500 A, preferably thermal triggers to a current of, for example, greater than 3000 A with a tripping time greater 10 ms, and the hinged armature system is designed for a short-circuit current of, for example, greater than approximately 5000 A.

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