Borsi - Institute of Electric Power Systems, Division of High Voltage Engineering, Schering Institute University of Hanover, Germany
Gockenbach - Institute of Electric Power Systems, Division of High Voltage Engineering, Schering Institute University of Hanover, Germany
Wasserberg - Institute of Electric Power Systems, Division of High Voltage Engineering, Schering Institute University of Hanover, Germany

Insulating liquids together with a solid insulant immersed therein is for many kinds of applications like power transformers since more than 100 years in use and remains for the near future still one of the most suitable insulating systems for many applications. A dominant parameter, accelerating the aging and reducing the strength of such insulations, is humidity, thus drying procedures are required to extend lifetime and operation reliability. This contribution presents new systems, which perform a continuous desiccation of the insulating system of power transformers during service and are beneficial for insulating liquids as well as for solid insulations immersed therein. The advantages of the different procedures in comparison to conventional approaches are discussed and an outlook on a new system for the reduction of the water uptake of breathing transformers is given.

Power transformers, in-service drying, lifetime extension