| 摘要 |
<p>A protective means for a series capacitor in a highvoltage network comprises a voltage-dependent resistor (varistor) arranged in parallel with the series capacitor, a spark gap arranged in parallel with the varistor for shunting the latter when it becomes overloaded, a currentsensing member, for example a current transformer, for sensing the current through the varistor, an energy absorption detector for sensing the temperature of the varistor, and a pulse transformer electrically or magnetically connected to the current-sensing member, for triggering the spark gap. During normal operation of the network and the series capacitor the current-sensing member is short-circuited by a normally closed switching device. This switching device is controlled by the energy absorption detector in such a way that the switching device is opened if the temperature of the varistor exceeds a predetermined level, whereby a trigger pulse, generated directly by the varistor current via the current-sensing member and the pulse transformer, may pass to the spark gap.</p> |
