Comparison of Mineral Oil Behavior with and Without the Presence of Catalysts During Accelerated Thermal Aging

This article deals with an impact of the presence of catalysts on the properties of mineral oil during accelerated thermal aging. The mineral oil was thermally aged both in the catalytic and in the non-catalytic environments. The catalysts used were copper and electrical insulation paper (Kraft paper) which belongs to common parts of power transformers. The experiment was aimed to verify whether and how the catalysts influence the degradation rate. The oil was exposed to an elevated temperature (130 °C) during the process of accelerated thermal aging for 120 hours. During this time, selected parameters were continuously monitored and measured by the several diagnostic methods which include dielectric strength test, Fourier Transform Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC). FT-IR and DSC were utilized to provide new observables and endpoint criteria to assess the remaining useful life of mineral transformer oil. Obtained results so far confirm that mineral oil aged with the presence of catalysts appeared to have a faster aging trend and some observables evaluated from FT-IR and DSC have promising trend desired for calculation of the remaining useful life of mineral transformer oil.