| 摘要 |
<p>The arrangement contains a summing current transformer with a pre-magnetising winding (6) through which an excitation current Ie flows. According to the invention, a voltage monitoring device (14) is provided in the secondary circuit which releases the latching magnet (9) at the same frequency as the excitation current Ie in the event of a component of the voltage in the secondary circuit being less than a predetermined limit. This voltage monitoring device (14) produces a fault current switch, sensitive to all types of current, which switches fault currents that are not smooth DC fault currents, independently of the voltage, and detects pure DC fault currents with the aid of its excitation current. This arrangement thus combines the characteristics of a fault current protection switch without electronics with a differential current protection switch. <IMAGE></p> |
