Breakdown characteristics of transformer oil based silica nanofluids

A fluid consisting of nano-sized particles is known as nanofluid. It manifests better cooling abilities compared to the host fluid. The aim of this study is to analyze the AC and impulse breakdown strength of mineral oil based SiO
₂
nanofluids (NFs). The volume fractions used was 20%. The influence of moisture on AC breakdown strength was investigated. Moreover, the positive and negative impulse breakdown strength was measured and compared with pure oil. The positive lighting impulse breakdown voltages indicated an enhancement as compared to pure oil where the measured negative impulse breakdown voltages of nanofluids were lower than the host oil. The modification mechanisms of nanoparticles on breakdown properties of mineral oil were also discussed.