Insulation and Cooling Performance of Transformer Oil Based Nanofluid

The transformer oil in electrical equipment is mainly used for insulation and cooling purpose of the equipment. This paper presents the experimental results of insulation and cooling performance of transformer oil (mineral oil and MIDEL-7131) based nanofluids. The nanofluids were prepared using SiO
2
nanoparticle with a percentage concentration (W/V ratio) of 0.1, 0.3, 0.5 and 0.7. The results were compared with the base oil and it was found that with the increase in concentration of nanoparticle in the base oil, thermal conductivity of the nanofluid increases by 5% for a percentage concentration of 0.7% in mineral oil and 10% in MIDEL-7131. The impulse dielectric strength of the nanofluid sample also increases up to 25% at a percentage concentration of 0.5% in mineral oil based nanofluid and 18% in MIDEL-7131 oil based nanofluid as compared with their base oils. But unfortunately the AC breakdown voltage of the nanofluids decreased, this decrease in AC breakdown voltage may be due to the increase in moisture content.