Experience with PDA diagnostic testing on hydraulic generators

This paper describes the capability of the partial discharge analyzer (PDA) test to distinguish between the various operative mechanisms of stator winding insulation deterioration (if any). The ability to distinguish between the various mechanisms yields significant benefits in scheduling priorities for inspection, repairs, and possible locations of deterioration. Two normalized quantity number charts are presented: one for polyester and epoxy stator insulation systems, and one for asphalt-mica and mica folium stator insulation systems. Their stated insulation damage relationships are based on Ontario Hydro´s operating experience over the past 15 years