Partial discharge measurement as aDiagnostic ToolforHV-Equipments

Insulation monitoring anddiagnostic arethebaseof condition maintenance andessential foraneconomic usage ofhighvoltage equipment. Electrical breakdowns ina smallregion ofthe insulating systemarecalled partial discharge. The appearance andtheintensity ofthese partial discharges areaquality criterion foranelectrical equipment rating andtherefore anestimation ofthecondition ofthe insulation system canbedone. Sothepartial discharge measurement hasbecomea fixpartinindustrial applications asanondestructive highvoltage test. It usesthedifferent physical effects in different insulating systems todetect significant parameters to givedirectly orindirectly information aboutthe equipment condition. Not onlyhighfrequency electrical transient phenomena andespecially currents arecaused bypartial discharges also optical, acoustical andchemical reactions andeffects occur. Different techniques areinusetoobserve relevant parameters andaresupposed toprovide anearly warning. Inthefull paperanoverview ofpartial discharge measurement techniques, particularly inthe areaof non conventional measurements, for diagnostics isgiven.