In the above equation, ff1;) = Jl + av .. bv2 , ..Il. ... a and
b are parameters of equation (10), and 11' is the percentage
volume of the NPs in the transformer oil. The parametric
values of the top oil temperature model have been
determined based on laboratory experiments on prototype
transformers. Consequently, the limiting load in pu for any
top oil temperature can be reworked from Eqn. (10) as