DE739704C - Device for switching arcing faults one or more times - Google Patents

Description

Device for switching arcing faults one or more times The invention relates to a device for switching one or more times of arc short circuits in systems with inductive system parts, in particular Transformers. In order to switch off the faulty line as quickly as possible, excitation elements are often used, in particular overcurrent relays with a high response sensitivity. However, there is then the risk that the switched off when switched on again Line or power pack occurring, caused by the aforementioned inductances Magnetizing current surge a sudden unwanted switching off of the power supply unit is brought about.

In order to remedy this deficiency, it has already been proposed in the Switching on or switching on again of the by the short-circuit forwarding device controlled system part so long ineffective to the trigger coils of the excitation relay do, e.g. B. short-circuit until the magnetizing current surge to such Value has subsided that a triggering relay can no longer take place. The triggering relays are expediently made ineffective as long as the switch-on pulse, which is fed to the short-circuit continuation switch continues.

In spite of this safety measure, however, it may now be possible after the reconnection triggers the short-circuit continuation switch will. The reason for this is to be found in the fact that the short-circuit progression in a very short time interval that is going on and, as a result, the available standing time is not sufficient to completely restore the contacts of the stimulating members to open. After the switch is switched on again, under certain circumstances especially if the preparations for the next upgrades are automatic take place, the tripping circuit of the incremental switch, since the contacts of the excitation relay have not yet opened, closed again and thus a Switch-on pulse are fed to the incremental switch.

In order to avoid such false tripping with certainty, suggests the present invention suggests disabling the stimulating members preferably by short-circuiting their relay coils before the restart pulse is emitted to the continuation switch, preferably at the same time as the short-circuit continuation switch is switched off to undertake. So it is not only the restart command for the incremental switch waited, but earlier, and expediently at the same time as the delivery of the switch-off pulse to the incremental switch, the ineffectiveness of the excitation elements brought about.

The relay technical implementation of the measure according to the invention can be done in a variety of ways without difficulty, e.g. B. can disable it the excitation elements are initiated by auxiliary relays, which are from the same control current operated, which also controls the triggering of the incremental switch.

In systems in which the short-circuit forwarding is a so-called Making free jet switch, the arrangement is expediently made so that the Contacts on the short-circuit continuation magnet of this switch that pull the the switch contact pins and the blowing of the isolating distance between these contact pins initiate, also control the deactivation of the stimulating elements.

The invention is particularly suitable for such switching devices, where the shutdown is initiated by extremely sensitive overcurrent relays will.

Claims (2)

PATENT CLAIMS: i i. Device for switching arcing faults one or more times, in particular arcing short-circuits, in electrical line systems with inductive system parts, in particular transformers, characterized in that the starting members which initiate the switching are rendered ineffective by short-circuiting their relay coils before the time the switch-on command is given to the switch preferably already at the time of the switch-off command to the incremental switch. 2. Device according to claim i in connection with a free jet switch that takes over the switching, characterized in that that the deactivation of the excitation members by those contacts on the incremental magnet of the incremental switch is controlled, which pulls the switch contact pins apart and initiate the blowing of the separating distance between these contact pins.