Investigation of the Stability and Insulating Properties of Mineral Oil-Based Surface Modified Silicon Nanofluid

The requirement for high voltage is growing extensively, which has obligated to enhance the dielectric and thermal properties of the insulators. Nanofluids (NFs) are a new class of insulating material that exhibits exceptional thermal and electrical characteristics. The relative permittivity and conductivity of Si nanoparticles (nSi) of diameters 10–30 nm synthesized from the p-type wafer are ideal values for free charge trapping; hence the mixture of mineral oil (MO) and nSi has the potential to replace the standard insulating oil. During the pre-breakdown phenomena of the insulator, the nSi in the base fluid act as a charge trap, capable of capturing about 45 electrons with a significantly shorter relaxation time of
$1.42\times 10^{-{14}}$
s relative to the streamer propagation time. Oleic acid, an oil-soluble dispersant, improved the dispersion and stability of the NFs. The FTIR analysis determined the type of interaction as chelating bidentate between the oleic acid and the nSi surface. The impulse breakdown voltage (BDV) of the NFs revealed the effect of trapping the free charges generated by the molecular ionization on enhancing the impulse breakdown strength. The relative permittivity measurement of the NF followed the Clausius–Mossotti polarization model of a mixed dielectric. Due to increased nanosized pores (with the number of nanoparticles), partial discharge inception voltage (PDIV), and the ac BDV were reduced with concentration.