Impact of Moisture on AC Breakdown Voltage of Crude, Refined and Transesterified Groundnut Oil-based Liquid Insulations

With the aim of analyzing the ability of vegetable oil-based liquid insulation as alternate medium under moisture-rich environment, this study presents an experimental analysis of impact on breakdown voltage characteristics vegetable oil-based insulating liquids for the moisture inclusion with oil sample. The study has been proposed to carry out with different categories of groundnut oil in crude form, refined form and transesterified form. The moisture inclusion range of 5 ppm to 25 ppm is considered based on the literature with the scope of having lower solubility level and less than 50% of water saturation level for avoiding wet transformer conditions. Experimental investigations have been done on AC breakdown voltage of three categories of groundnut oil for inclusion of proposed range of moisture. With an increased moisture level from 5 to 25 ppm, significant reduction in breakdown voltage of oil samples has been obtained with the average percentage of 53 to 67% which may be due to possible modification in the molecular component of oil with the influence of moisture's polarization characteristics. Based on the experimental observations, the empirical power equations developed based on the regression method to predict the approximate breakdown voltage at different moisture levels.