Parameter studies on surface partial discharge inception of polluted, tangential electrically stressed boundary surfaces

Compact stator end windings of large turbine generators are stressed by tangentially stressed boundary surfaces. To achieve an optimal design, the electrical field strength has to be below the partial discharge (PD) inception field strength. In regular operation - especially for air cooled machines - several environmental impacts could affect the PD inception field strength inside stator end winding configurations, especially the influence of dust, dirt and ambient moisture. Therefore investigations are necessary to classify contamination influences in regard to its potential to cause surface corona.