Experiences with Application, Diagnostic Value and Impact on Asset Management of Insulation Oil Analysis

This paper presents and discusses the Swiss experiences with the application, analysis, value and impact on asset management of regular insulation oil diagnostics, which includes dielectric-chemical parameters, dissolved gas analysis and furan analysis. Most frequently oil laboratories determine the dielectric-chemical parameters according to IEC 60422. Here the interfacial tension, neutralization number (acidity), colour number and dielectric dissipation factor tangent delta (conductivity) allow for collecting a consistent record – even over decades – on the ageing performance of the observed oil-paper-insulation. This is not true for moisture content and breakdown voltage. Though these parameters are closely linked to each other (moisture strongly influences breakdown voltage), the…