Fault current acquiring device, responding to any current, with alternating or pulsating fault current acquiring device, unaffected by DC fault currents

摘要

The invention relates to a fault-current detection device having a summing current transformer arrangement (1) which has primary windings (2) for a circuit to be monitored and has a secondary winding (3). DC fault currents result in the converter being premagnetised, which premagnetisation has a significant adverse effect on the tripping of the fault-current detection device for alternating fault currents and pulsating direct false currents. This defect is remedied by shifting the magnetisation characteristic by, for example, loading the secondary winding (3) with a resistor (4).