A Review on Properties, Opportunities, and Challenges of Transformer Oil-Based Nanofluids

Table 2

AC breakdown enhancement of transformer oil-based nanofluids reported in literature.

Author/year	Method of preparation	Nanofluid	Average particle size (nm)	Concentration; (vol%)	Enhancement ratio
Segal et al./1998 [22]	Two-step	Fe3O4/mineral oil	10	—	42.8%
Sartoratto et al./2005 [27]	Two-step	Fe2O3/mineral oil	7.4	0.016	12.8%
Du et al./2011 [28]	Two-step	TiO2/mineral oil	20	0.075	19%
Liu et al./2012 [29]	Two-step	SiO2/mineral oil	15	0.0074	17%
Li et al./2012 [30]	Two-step	Fe3O4/vegetable oil	30	—	19.8%
Hanai et al./2013 [31]	Two-step	ZnO/mineral oil	34	0.0005	8.3%
Rafiq et al./2016  [32]	Two-step	Fe3O4/mineral oil	15–20	0.04	16%