The initiation and growth of AC tree in polyethylene

An electrical tree was generated from a semiconducting needle electrode in polyethylene. The process form the initiation to growth up to a few 10s of microns was observed and recorded by an optical microscope simultaneously with the partial discharge measurement. The results on several samples were statistically analyzed to further the understanding of the relationship among tree growth, partial discharge, and branching. Based on the results, a possible qualitative model of tree initiation and initial tree growth is presented.<<ETX>>