Convective heat transfer behavior and AC dielectric breakdown voltage of electric power transformer oil with magnetic colloidal nano-fluid: An experimental study

Abstract

This research reports on an experimental investigation into the alternating insulation breakdown voltage (AC) and convective heat transfer behavior of nano-oil for application in electrical transformers. The base fluid of the examined nano-oil is nitro libra type transformer oil, one of the common mineral oils used in transformers. It contains iron oxide magnetic colloidal nanoparticles. Upon fabrication of the experimental apparatus in the lab, an experimental study on convection heat transfer is performed under laminar flow conditions and with a continuous heat flux applied to the wall. BA100 breakdown voltage measurement instrument based on the IEC 60156 standard is also used for alternating breakdown voltage testing. The current findings from the experimental investigation of convective heat transfer are compared with and verified by the experimental results available in the literature. The experimental results demonstrate that the convective heat transfer coefficient of the iron oxide magnetic nanoparticle-prepared nano-oil is on average 4.51% higher than that of base oil. These particles have an average size of 23 nm and a volume concentration of 0.1%. Additionally, compared to base oil, nano-oil with a volume concentration of 0.1% has a 23.8% higher dielectric breakdown voltage.

Keywords

• Transformer oil
• Convective heat transfer
• Nano-oil
• Nanoparticles
• AC Dielectric breakdown voltage