Electronic excess-current relay

摘要

The invention relates to an electronic excess-current relay, having a current transformer and a downstream rectifier, whose output voltage in the case of an excess current supplies both the measurement voltage which detects the excess current and also the supply voltage for the electronics, a saturable transformer being provided as the current transformer and the r.m.s. value of the output voltage, which is limited by the saturation influence as the current rises, being used as the supply voltage for the electronics, and the instantaneous values of the output voltage being used as the measurement voltage (Fig. 1). <IMAGE>