An online method for the assessment of moisture in a power transformer is presented in this paper. It is experimentally tested on simple insulating materials as well as on a sample bushing insulation. It is finally tested during the drying of a 110 kV transformer. The results are presented and show that the method is clearly able to distinguish between levels of moisture in the range of interest.
M. K. Ilampoornan, Jayashankar, V., V Kumar, J., and Dr. Madhu Mohan N., “On-line assessment of moisture in a power transformer”. 2010.