Effect of ZnO Nanoparticles on Impulse Breakdown Characteristics of Mineral Oil

Nanofluids (NFs) have demonstrated a great capability of enhanced dielectric and thermal characteristics of base insulation liquids. Therefore, mineral oil-based nanofluids are believed to be a possible alternative to conventional mineral oils in power transformers, leading to an influential way to improve the whole performance of power transformers. This paper investigates experimentally the effect of Zinc Oxide (ZnO) nanoparticles on the standard impulse breakdown characteristics of transformer mineral oil. The standard lightning (LI) breakdown voltages under quasi-uniform and nonuniform electric fields for both positive and negative polarity were measured. The results show higher LI breakdown strength of nanofluid compared to base mineral oil for positive polarity under quasi-uniform and nonuniform electric field, whereas, for negative polarity under nonuniform field, breakdown strength of nanofluid is slightly reduced compared to base mineral oil. The possible modification mechanisms were also discussed to elucidate the role in which nanoparticles play in influencing the electric breakdown process.