Partial discharge. IX. PD in gas-insulated substations-fundamental considerations

For pt.VIII see ibid., vol.7, no.5, p.9 et seq. (1991). The physical aspects of partial discharge (PD) in SF/sub 6/ gas-insulated substations (GIS) are reviewed. The orientation is toward present and developing techniques for evaluating defects in solid and gaseous insulation systems on the basis of PD measurement. Standard evaluation methods provide an indication of PD in GIS, but cannot quantitatively determine the type and size of defect. Statistical analysis of PD activity, together with physical models for the various types of discharge and defects, provides the basis for more advanced interpretation. Measurements of PD activity that do not require an absolute calibration are of greatest utility.<>