A model for the simulation of relaxation phenomena in dielectrics

A simulation of the behavior of the complex permittivity in a polymeric material as a function of frequency is presented. Starting from experimental data and taking into account the occurrence of a distribution function in the relaxation times, an electrical equivalent circuit for each material can be established. Then, the model is used to analyze some insulating systems. The curves are calculated for a stratified insulation and for a single material subjected to chemical degradation. An experimental study on ad hoc polypropylene films purposely processed with different concentrations of a particular polar additive is presented and discussed on the basis of the model. Several possible applications are considered. >