Power transformers are vital assets in
electric power systems, as they are essential in maintaining
a reliable supply and very high in cost. Nowadays, society
has become more and more dependent on the availability
of power, putting pressure on the reliability, availability
and cost efficiency of power supply. These assets operate
under high electric stresses and although transformers
... [Show full abstract] are
extremely energy efficient, the dissipated heat is a limiting
factor for the maximum loading of power transformers.
The insulating medium must be capable of dealing with
large electric stresses, strong electro-mechanical forces and
high temperatures. The life of a power transformer mainly
depends on the condition of the paper-oil insulation
system. Manufacturers often define the expected life of
power transformers to be between 25 and 40 years. Some
transformers in service are now approaching this age, and
it is important to estimate their remaining lifetime in order
to prevent premature shutdown of transformers. Knowing
the condition of the transformers is an essential factor to
make an economical decision for transformer replacement
and maintenances. This paper presents a mathematical
model to estimate the remaining life through assessment of
furfural content in the oil and degree of polymerization of
the insulating paper.