Effect of nanoparticles on electrical characteristics of transformer oil-based nanofluids impregnated pressboard

In order to improve the electrical characteristics of transformer oil-impregnated pressboard, transformer oil-based nanofluids were used to impregnate pressboards. It is found that nanofluid-impregnated pressboard (NP) exhibits substantially higher AC and DC breakdown voltage than that of pure oil-impregnated pressboard (OP). Pulse electroacoustic measurement (PEA) was carried out to study the difference of space charge distribution and decay characteristic in OP and NP. It has demonstrated that NP has a more uniform internal electric field, which is caused by a higher charge transport rate compared to OP, resulting in the improved electrical insulating properties.