THE IMPACT OF PET INTERFACES IN THE DIELECTRIC STRENGTH OF MULTILAYERED ELECTRICAL INSULATION UNDER HIGH INTENSITY FIELDS

Konstantinos Theodosiou - Ioannis Gialas - Isidoros Vitellas - Dimosthenis Agoris

   The influence of PET interfaces in, polymeric insulation, dielectric strength is examined by this paper. PET (Polyethylene terephthalate) films of different thickness are put together forming a planar sample of a typical thickness of 200 μm and subjected to AC ramp voltage, until the dielectric breakdown. Experiments were executed for investigating the role of the position of the first, the second and the last interface in the sample, as well as the influence of interface number n. All the experiments were executed with the same voltage rising step, the breakdown AC voltage V_b was measured and the dielectric strength F_b was calculated. It was shown that interfaces act as deep trapping centers for electrons giving rise to the sample dielectric strength for sort time experiments. The more the number of interfaces, the higher the dielectric strength. Moreover the thinner the first film, the higher the dielectric strength for the sample. It was also found that the position of the second interface does not play an important role in the process and the position of the last interface is significant only in case that samples have the same first interface position. The results were tested using finite elements simulation.

Keywords: PET, polymeric insulation, dielectric breakdown, dielectric strength, finite elements simulation

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