Electro-thermal and mechanical aspects of thermally aged cellulose insulation impregnated with nanofluids

Abstract

Natural ester nanofluids offer improved dielectric and thermal properties than non-biodegradable mineral oil. In the present work, cellulose samples impregnated with unfilled and nanofilled mineral oil and ester are subjected to thermal aging at 130 °C for 168, 336, 504, and 1200 h under open beaker conditions. After 1200 h of thermal stress, the AC breakdown voltage, thermal conductivity, and tensile strength of natural ester impregnated cellulose is 36.13%, 0.46%, and 1.09 times higher than that of mineral oil impregnated cellulose samples, respectively. Also, the AC Breakdown voltage, thermal conductivity, and tensile strength of 0.02 wt% natural ester nanofluid impregnated cellulose is 37.81%, 1.7%, and 1.1 times higher than that of cellulose impregnated with 0.02 wt% mineral oil nanofluid, respectively. The present measurements demonstrate an improvement in the solid insulation performance with natural ester nanofluids, suggesting a possibility of extended service life of solid insulation in liquid filled high voltage transformers.