Dielectric Response Analysis of Nano-Impregnated Pressboard in Natural Ester Oil Incorporating TiO₂ and Fe₃O₄ Nanoparticles

Oil-impregnated pressboard (OIPB) in transformers is commonly used, favored for its economic benefits and enhanced physical and electrical properties. Lately, there has been a surge in research to improve the insulating properties of OIPB. The present study aims to assess the changes in the dielectric properties of OIPB with the addition of nanoparticles. This study encompasses the modification of OIPB through the incorporation of two types of nanoparticles, TiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> and Fe304 mixed into natural ester oil (NEO) at weight fractions of 0.03%, 0.05%, and 0.1%. The electrical properties of OIPB and nanofluid-impregnated pressboard (NFIPB) are assessed by focusing on the dielectric response using frequency domain spectroscopy (FDS). The FDS analysis is performed using a Solatron 1260 impedance analyzer, covering a frequency spectrum from 1 mHz to 10 kHz. Results from the FDS indicate that the nanoparticle incorporation substantially influences fundamental dielectric properties, including relative permittivity, dissipation factor, and conductivity of the NFIPB, in contrast to the conventional OIPB. It is observed that the incorporation of the nanoparticles leads to a reduction in the permittivity of OIPB. Further, the Cole-Cole model is used to study the relaxation phenomena observed in conventional PB and NFIPB.