AC loss and DC conduction mechanisms in polyethylene under high electric fields

The paper describes extensive experimental investigations concerning AC loss and DC conduction in polyethylene (PE) subjected to strong electric fields up to about l00kV/mm. Based on an electronic charge carrier hopping transport model including trap-like and donor-like states it is shown that the current is bulk-limited under both AC and DC conditions. However, the sources of the electronic charge carriers taking part in the AC loss and DC conduction processes, respectively, are different from each other: At direct voltage the electrons are injected from the cathode whereas at alternating voltage they are predominantly activated from donor-like states in the bulk of the dielectric by a Poole-Frenkel-mechanism.