Modeling of the low-frequency dielectric response of rotating machine stator insulation system

In order to assess the state of the rotating machine insulation winding system, time-domain dielectric measurements are frequently conducted. Such measurements, which are related to the low-frequency dielectric response of the insulation system, depend on the way the components of the insulation system are laid out, the aging of the materials and on external factors such as temperature, moisture absorption or contamination. In this paper, a dielectric model of the insulation system that combines effects of both the straight and the end-winding portions was developed and compared with experimental measurement for unaged bars.