Electrostatic field analysis of high voltage generator stator insulation systems

High voltage generators are being subject to higher voltage ratings and are being designed to operate in harsh air cooled environments. A better understanding of the electrostatic field performance of these designs must be developed. Dielectric parameters such as insulation thickness, spacing, and material types are major design considerations. A very powerful tool available to obtain a better understanding of the dielectrics is with the use of Finite Element Analysis (FEA) programs applied to the dielectric design. The analysis of various stator coil configurations can be used to design the dielectric system to meet or exceed the voltage strike and creep requirements. Of most importance, the design analysis can be used to predict corona inception voltage and identify the location of the corona initiation. This paper describes the process used to perform the design analysis and presents an example design with calculated and measured parameters to ensure an adequate design.