Dissipation current waveform observation of polyethylene film under ac high-field [power cable insulation applications]

Polyethylene is widely used as power cable insulation. To investigate the conduction mechanism of power cable insulation under ac high fields, it is very important to acquire the dissipation current under an actual running field. This paper discusses the conduction mechanism of LDPE film under a high ac field, specially the two peaks of the dissipation current waveform in each half cycles at 200 Hz. The film thickness dependence of the dissipation current waveform at 200 Hz was examined. As the results of experiments and analyses, charge movement in the bulk may be attributed to the appearance of the latter part dissipation current waveform peak of each negative and positive half cycle.