Dielectric Loss Model of Transformer Oil-Based Nanofluids with ZnO Nanoparticles

A new kind of transformer oil-based nanofluids(NFs)with ZnO semiconducting nanoparticles is prepared to investigate the influences of adding nanoparticles on dielectric loss tangent of transformer oil.The mechanism on how the nanoparticle volumetric concentration and environmental temperature affect the NF dielectric loss tangent is also discussed.A new dielectric loss model based on conduction loss and nanoparticle relaxation loss is proposed. The experiments show that the ZnO NF dielectric loss tangent linearly increases with the nanoparticle volumetric concentration and exponentially increases with the temperature. Meanwhile the calculation of dielectric loss model coincides well with the experiments.The further analysis suggests that for ZnO NFs the dielectric loss tangent is dominantly determined by conduction loss,and the influence of nanoparticle relaxation loss is slight.