Thermal conductivity of high voltage stator coil groundwall insulation

A current topic of interest and technical importance is the thermal conductivity of the vapor pressure impregnated (VPI) groundwall and the stator core slot contents. In order to improve turbine generator performance, there must be improved thermal conductivity for increased thermal power dissipation capability in the stator slot. A benchmark study of the current Westinghouse VPI stator coil groundwall insulation including modeling to estimate thermal conductivity has been investigated. This paper presents a model showing a relationship between the VPI groundwall insulation composition and thermal conductivity. The VPI groundwall insulation thermal conductivity model compares very well with physical measurements. The model generated provides a materials design tool which can estimate composition effects on thermal conductivity of stator coil groundwall insulation