Applying of hygroscopic materials to dry transformer insulation

The problems related to the effects of high moisture content in the transformer insulation system and the risk resulting from the need for its immediate drying can be avoided by using a non-invasive method of continuous drying of solid insulation by means of high hygroscopic sorbents. The article compared the hygroscopicity of selected sorbents: molecular sieves 3A, 5A and 13X, aluminum oxide and silica gel. It was found that the highest hygroscopicity, for a low value of relative air humidity, is characterized by a 13X molecular sieve. For this reason, this material was selected for further testing by checking its ability to dry mineral oil