Phenomenological model of nonlinear dielectric losses related to the intrinsic conductivity of dielectrics

Abstract.

A phenomenological approach was applied to the dynamics of the intrinsic electric conductivity of dielectrics in an electric field in order to analyze its contribution to dielectric losses. The proposed differential equation contains only two parameters - the effective time $\tau_{F}$ of conductivity decay in an electric field, and $\tau_{R}$, the time describing the recovery rate of the conductivity after switching off the field. The proposed approach predicts a linear dependence of specific conductivity of dielectrics on the sample thickness, as experimentally confirmed by Du Pont [1] for Teflon FEP. The field and time (or frequency) dependences of intrinsic conductivity and related dependences of dielectric losses were calculated, analyzed and illustrated with the published experimental data. The results show that the discussed contribution in dielectric losses is characterized by two hyperbolas (instead of one) while the distance between the branches depends on the intensity of applied electric field.