Breakdown voltage characteristic of MO and RBDPO mixture for power transformer insulation

This paper presents the breakdown voltage characteristics of Refined, Bleached, and Deodorized Palm Oil (RBDPO) and mineral oil (MO) mixture. The ratio of 10% to 100% of RBDPO was mixed with MO at 40°C, 50°C and 60°C. The experiment was conducted according to IEC 156 standard by using BA100, Fully Automatic Portable Breakdown Voltage Test Set. The results from the experiment show the breakdown voltage for all mixtures and temperatures were fulfilled the IEC standard, which is greater than 30kV. The result shows that the descending percentage of MO to RBDPO cause gradually increases of breakdown voltage and fulfill the IEC 156 standard. The breakdown voltage for all temperatures was abruptly decreased at 30%RBDPO/70%MO mixture. The optimum breakdown voltage of the oil mixture was obtained at 80% RBDPO/20%MO.