Finite Element Based Comparative Analysis of Positive Streamers in Multi Dispersed Nanoparticle Based Transformer Oil

The dispersion of dissimilar nanoparticles (NPs) in transformer oil (TO) has a major impact on fast propagating positive streamers. This work investigates the positive streamer dynamics in TO modified by dispersing both Fe3O4 and Al2O3 NPs at a homogenous concentration. The hydrodynamic drift diffusion model of positive streamer evolution and propagation are solved using the commercial software package COMSOL Multiphysics. The impact of multiple NPs (MNPs) has been analysed for streamer propagation, electric field intensity, electron density, and space charge density of modified TO. MNPs successfully reduce streamer propagation velocity by 50%, 17%, and 37.5% comparing to pure oil, Fe3O4 based nanodielectric fluids (NDFs), and Al2O3 based NDFs, respectively. The spatial distribution of electron density reveals the loss of electrons from the ionization region until the saturation of NPs. A comparative study demonstrates that MNPs significantly alter the streamer dynamics and augment the dielectric strength of TO compared to individual NPs.