original rapeseed oil.
The Table 1 compares the main properties of this new
composition with those of other insulating liquids. The ester
composition has lower viscosity and pour point than those of
others natural esters (i.e. vegetable oil) and this is an advantage
concerning the cooling and low temperature behavior in
transformers. On the other hand the ester composition has a
much lower flash point than other esters (natural and synthetic),
and, as mineral oil, it cannot be classified among nonflammable
liquids (Class K). Its density is comparable to that
of mineral oils. Noticeable is the higher neutralization value of
the ester composition, but further studies show the high acidity
does not have a deteriorating effect on the solid insulation. This
is a major difference to mineral oils. At last, its environmental
features stay alike those of vegetable oils, i.e. far better than
mineral oil ones.