Novel systems for the upgrading of power transformer insulations

Although solid and gaseous insulations have become increasingly popular during the last decades the application of insulating liquids together with a solid insulant immersed therein is still essential for some kinds of applications like power transformers. A dominant risk, reducing the strength of such insulations, is water, thus drying procedures are required to extend lifetime and operation reliability. As actually used systems for this purpose comprise several imponderabilities new systems are required. 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.