D.C. Partial Discharge and Current in Polyethylene

Simultaneous measurement of D.C. partial discharge and electric conduction was carried out. The following results were obtained: (1) The number of partial discharges occurring per unit time and also the electric current obey an exponential law exp (- W / k T ) with the same activation energy, W . This indicates that the number of discharge sites does not vary with temperature and that partial discharge is governed by the electric current. (2) The number of partial discharges increases more rapidly than the electric current with the increase in the applied voltage. This means an increase of discharge sites with the increase in voltage. (3) The time dependence of the number of partial discharges is related to that of the electric current and the position of discharge sites between the electrodes in the sample. (4) The generation of partial discharges follows the Poisson distribution, showing that discharge sites have no correlation with each other.