Abstract – Environmental considerations demand alternatives for
the current mineral oils used in many electrical equipment, such
as transformers. Because of their excellent biodegradability and
non-toxicity, relative to petroleum derived products, the use of
the vegetable oils is on the rise as insulating and heat transfer
liquid in electrical devices. In addition such natural esters have a
favorable lower flammability, but their viscosity and low
temperature behavior is not well suited to applications in cold
climate and/or with natural cooling system. That is why a new
insulating fluid, based on modified vegetable oil, has been
developed that presents properties very similar to those of the
standard insulating mineral oils used in transformers.
This paper presents the formulation of this low-viscosity ester
fluid, and it reports the results of a field experimentation carried
out to assess the behavior of the fluid in real conditions.
Keywords – natural ester; insulating liquid; low-viscosity
composition; ML/LV tranformer