Bubble Formation in Vegetable Oil-filled Power Transformers

It is important to understand bubble formation during transformer overload or its initial energisation, as it can lead to the failure of the unit. This phenomenon has been investigated in a mineral oil system, but not in a vegetable oil system. Vegetable oil is thought to be able to better resist bubble formation than mineral oil. This study investigated bubble formation during overload temperatures in a vegetable oil system, and the results were then compared to a mineral oil system which was studied previously using similar test equipment and method.