Abstract: It is generally known that addition of conducting
or insulating particles to mineral transformer oil, lowers its
breakdown strength, Ed' However, if the particulates are of
molecular dimensions, or nanoparticles, (NPs), as they are
called, the breakdown strength is seen to increase
considerably. Recent experiments by the authors on oil
cooled power equipment such as transformers showed that,
nanofluids comprising NPs of selected oxides of iron, such
as Fe304, called magnetite, added to transformer oil
increased the breakdown voltage of the virgin oil and more
importantly a remarkable enhancement in the thermal
conductivity and the viscosity and hence an increased
loadability of the transformer for a given top oil temperature
(TOT).