Partial discharge characteristics of oil-immersed insulation systems under DC, combined AC-DC and DC reversed polarity voltage

Abstract

Breakdown characteristics of insulating oil, under combined ac-dc voltage and dc reversed polarity voltage, and partial discharge characteristics of oil-immersed insulation, under combined ac-dc voltage and polarity revesal of dc voltage Were made clear by elementary experiments. After that, a numerical dc field mapping method for electric field analysis of two-dimensional configurations which consist of composite insulation and field mapping methods under combined ac-dc voltage and dc reversed polarity voltage were proposed. Futhermore, partial discharge characteristics of transformer insulation under dc, combined ac-dc voltage were experimentally made clear by practical trial models.