Indirect Contacts Protection for Multi-Frequency Currents Ground Faults

In recent decades, most electrical appliances have been deeply transformed with the addition of power electronics. In case of failures, the fault current is no longer sinusoidal and the effects on human beings are, up to now, not well known. Non sinusoidal currents can be decomposed in a series of sinusoidal currents: for this purpose, the IEC Standard 62423 defines a test waveform for F type residual circuit breakers, which is composed of different frequencies weighted sinusoidal currents. In this paper, the human body response to multi frequency currents has been investigated considering the perception threshold for the test waveform defined in the IEC 62423.