Aging of Transformer Pressboard Impregnated With Conductive and Semi-Conductive Nanoparticles Dispersed Soyabean Oil Blend

Vegetable oils are being continuously tested as alternative oils to replace nonbiodegradable and inflammable mineral oil (MO). The dielectric and physiothermal properties of vegetable-based insulating oils are further enhanced by dispersing various nanomaterials in them. However, there is hardly any conclusive study available, which focuses on the effects of these vegetable oil-based nanofluids (NFs) on the aging characteristics of transformer pressboard (PB). This research targets on formulating a soyabean oil-based NF having semi-conductive TiO2 nanoparticles and conductive ZnO nanoparticles and to study the effects of aging on mechanical and dielectric performance of transformer PB when fully impregnated with these NFs. Results show that the impregnation of PB with both types of NFs results in overall improved mechanical as well as dielectric properties of PB. After 60 days of aging, the relative crystallinity and the breakdown voltage (BDV) of PB impregnated with TiO2 NF are 62.7% and 46.1 kV, respectively, whereas for ZnO NF, these values are 46.8% and 48 kV, respectively. However, both these values are higher than those of the PB impregnated with base oil blend (OB), which has the relative crystallinity and BDV of only 30.2% and 39.9 kV, respectively. Thus, when compared with one another, TiO2 impregnated PB shows better mechanical properties, whereas ZnO impregnated PB shows better dielectric properties. Thus, both types of impregnated PBs can be used for enhancing transformer operation depending upon the expected requirements.