Investigations on the conducting behavior of technical polyethylene at high electric field intensities (> 30 kV/mm)

To begin with the present paper reports on experimental investigations on the conducting behavior of technical polyethylene at high electric field intensities. It is aimed at differentiation of the current density variation with time caused by transient phenomena from the dependence of the steady current on the mean field intensity occuring in the course of long loading periods. Considering experimental results of investigations on return current distributions depending on preceding field loading a qualitative model of the conduction phenomena is developed. In order to quantify the parameters influencing the charge transport a numerical simulation code, based on the qualitative model, was written by means of which also such processes which cannot explicitly be measured (formation of space charges, occupation of trapping positions, variation of the sample field distribution with time) as well as their effect on the current behavior may be checked. (orig.)