New insulating liquids for high voltage apparatus

The combination of a solid and a liquid insulation is the most frequently used insulating system in high voltage apparatus, where components have to be insulated and loss heat has to be dissipated. The requirements on the liquid part of the insulating system are not only the electric and dielectric performance but also the performance regarding environmental requirements and dehydration capability as well as low inflammability. The contribution presents a comparison of the performance of different liquids concerning the electric behavior and some other characteristics for use in high voltage transformers.