Siemens Aktiengesellschaft

Michael Claus

Cezary Dzienis

Volker Rissland

Yilmaz Yelgin

Matthias Kereit

Joerg Blumschein

Henry Zimmer

Volker Henn

Gustav Steynberg

Jörg Blumschein

Robert Westermann

A first protective device monitors a first section of a power supply network for a symmetrical short-circuit and a second protective device monitors a second section for a symmetrical short-circuit. The second protective device is a reserve protective device, which emits a shut-off command to a power switch after a time lag when a symmetrical short-circuit in the first section is recognized. An oscillation recognition unit emits an oscillating signal which blocks the shutoff command if an oscillation in the power supply network has been recognized. External symmetrical short-circuits can be disconnected independently of an occurring oscillation, when the second protective device has recognized a symmetrical short-circuit in the first section, before the oscillation recognition unit recognizes an oscillation in the power supply network, the shut-off command is emitted independently of the presence of an oscillating signal if the lag time has elapsed.

Method and protective device for detecting a symmetrical short-circuit in a multiphase electrical power supply network

The invention relates to a method for automatically re-closing when there is a short-circuit in a line section of an electric energy supply line, whereby said section is defined by one switch respectively which comprises an allocated short-circuit detection device. According to the inventive method and after the switches have been released by a short-circuit, a re-closing instruction that is produced on the one end of the line section trips the switch on the other end. The aim of the invention is to carry out said method in such a way that the switch is treated with care as far as possible. The switch on the other end of the line section is tripped after a predetermined time delay provided that the short-circuit in the line section terminates during the time delay.

System and method for automatic re-closure and re-closing device

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Nuremberg, Germany

Michael Claus