Experimentation on humidity propagation in high voltage alternator stator bar insulation

The goal of this article is to present the latest experimental results concerning the water propagation in the main insulation of bars of a turbo-generator. These experiments should show a correlation between measurement of the isolation resistance and the rate of humidity and to determine: on one hand, from a qualitatively point of view, how the humidity is propagated (in which direction) into the insulation material, and on the other hand, from a quantitatively point of view, the propagation speed and the level of uncertainty. The final goal is to provide to the end user, a powerful tool in order to make the right decision in case of insulation weakness detection due to a high rate of humidity.