A study on the influence of partial discharges on the performance of solid dielectrics

The authors show that the Inverse Power Law model seems to fit the physical process of degradation of solid insulation under the influence of partial discharge activity. The present study also indicates that the presence of electrical trees in XLPE leads to partial discharges, the magnitude of which appears to depend on the tree length. Electrical treeing does not appear to contribute to tan /spl delta/ and insulation resistance. The influence of PD activity on the life depends on the type of insulation in which partial discharges are taking place. For example, partial discharge magnitude of 200 pC results in a characteristic life of 2500 hours for MPPF capacitors, whereas a PD magnitude as high as 9000 pC results in a life of more than 5000 hours for machine insulation.