Fractional-order circuit models of the human body impedance for compliance tests against contact currents

Compliance tests against contact currents presently require the usage of equivalent circuit networks aimed to reproduce the human body impedance in the frequency range 0-110 MHz. The IEC 60990 standard specifies an equivalent network that is valid up to 1 MHz, while a recent work from the authors has extended the validity of the IEC network up to 110 MHz. However, a number of 11 integer-order lumped elements was employed in the latter case. In this study, an equivalent network based on fractional-order circuit models is proposed in order to reduce the number of elements needed to fit the human body impedance. Moreover, the fitting of the mixed curve defined as the lowest impedance between the IEC network and the extended one is for the first time considered to provide a more protective compliance network in the whole frequency range.