ANALYSIS AND MODELING OF ELECTRICAL TREE GROWTH IN SYNTHETIC RESINS OVER A WIDE-RANGE OF STRESSING VOLTAGE

A simple accumulated damage analysis method and an empirical field-dri ven tree growth model are proposed to characterize and describe the sp atial and temporal development of electrical trees. Examples are prese nted for trees grown in CT200 and CY1311 epoxy resin pin-plane samples subjected to a wide range of 50 Hz alternating current electrical str ess. It is shown that a material's resistance to treeing may be descri bed quantitatively, allowing the relative performance of different syn thetic resins to be easily compared. For CY1 31 1 epoxy resin, tree st ructural characteristics change progressively from branch to bush stru ctures as the stressing voltage is increased. It is shown that the tim e to failure is primarily influenced by the local electric field and t he resultant tree geometry and fractal dimension of tree growth and is not simply dependent on the applied voltage.