Partial discharge pattern recognition as a diagnostic tool for stator bar defects

摘要

Partial Discharge (PD) Pattern of threernimportant types of defects in insulation systems of highrnvoltage rotating machines (the internal defect, therndamaged semi-conductive screen and the defect onrngrading coating) was studied. As test object, stator barsrnwith artificial defects similar to practical ones on thernground wall and end-winding of bars were used. Therninternal defect in insulation was furthermore realizedrnwith a thermal ageing procedure on machine bars. Therncomparison of PD patterns, that were caused byrndifferent defect on stator bars presents clearly that therndifferent defects generates different partial dischargerntypes and that the defect type can be recognized. Inrnorder to compare the influence of different load andrntemperature conditions on partial discharge activitiesrnfor the diagnosis and as a basic investigation for therninterpretation of off-line and on-line measurements,rnPD was also measured at different temperatures.