An investigation of partial discharge energy dissipation and electrical tree growth in an epoxy resin

Electrical treeing is a long-term electrical breakdown mechanism in polymeric high voltage electrical insulation systems. Recently physical models of electrical tree growth have been proposed in the literature in which the rate of damage accumulation was assumed to be proportional to the electrostatic energy dissipation by partial discharges. In this paper, experimental measurements of the electrostatic energy dissipated during tree growth in an epoxy resin was compared to the vaporization energy necessary to form tree structures of a given volume. The results showed that, for all tree structures examined, the vaporization energy required to form tree structures was between one twentieth and one seventieth of the total electrostatic energy input from the external circuit.