Diagnostics of the tree-inception in LDPE

The results of a study of the tree-inception process in low-density polyethylene, in the needle-plane configuration, under AC voltage, are represented in this paper. The tree inception was studied in visible, UV, and IR spectra with simultaneous monitoring of the partial discharge (PD) parameters. It was established that the tree inception is accompanied by radiation in the visible and UV spectra and by the local temperature rise on the sample surface by a factor of 1.5... 2, irrespective of the experimental conditions such as the applied voltage, the needle tip radius and interelectrode distance. It was found that between the temperature-temporal parameters and PD-parameters of the tree-inception process exists a correlation. It was shown that a diagnostics of the tree inception is possible by means of measurements of the local temperature rise on the dielectric surface and partial discharge parameters.