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

Table 4

Results for positive and negative impulse breakdown voltages and time to breakdown for mineral oil and corresponding nanofluids.

Oils	Gap distance (mm) (+/−)	Breakdown voltage (kV)		Time to breakdown (µs)		Streamer velocity (km/s)		Remarks
		Positive	Negative	Positive	Negative	Positive	Negative
U-60	25.4/25.4	86	170	12	27	2.12	0.94	[5]
U-60-Fe3O4 nanofluid	25.4/25.4	157	154	26	15	0.98	1.70
Nytro	25.4/25.4	88	177	16	23	1.58	1.10
Nytro-Fe3O4 nanofluid	25.4/25.4	156	173	25	17	1.016	1.49
U-60	55/55	225	340	25	28	2.2	1.96
U-60-Fe3O4 nanofluid	55/55	390	321	46	32	1.19	1.71
Mineral oil	25/25	77.6	—	15.2	—	1.64	—	[34]
TiO2 nanofluid	25	95.9	—	23.3	—	1.07	—
Mineral oil	25/25	86	170	12	27	2.12	0.94	[35]
Fe3O4 nanofluid	—	157	154	26	15	0.98	1.69
SiO2 nanofluid	—	156	163	17	26	1.44	2.87
Mineral oil	25/15	79.38	124.75	12.87	14.26	1.94	1.05	[29]
Fe3O4 nanofluid	25/15	108.5	106.3	25.33	11.03	0.98	1.36

Univolt 60 Exxon mineral oil.
Nytro 10x mineral oil. The standard deviation was 5% for the breakdown voltages and 20% for the breakdown times.