Investigation of the Partial Discharge Occurrence Criterion in the Stator Slot with Air-Cooled Turbogenerator

The research goal is investigation of the partial discharge occurrence criterion in the stator slot with air-cooled turbogenerator. To achieve this goal, a parametric numerical model of the stator slot with rods, identical to the geometry of the real design, has been developed. The feature of the model is the automatic accounting of the temperature dependences of the dielectric properties of the insulation system materials and the nonlinear dependence of the electrical strength of the air gap on its size and the temperature. The most important results are determined permissible limits of the external corona protection coating resistance, as well as the identified parameters of permissible design, technological deviations and characteristic defects to exclude or minimize slot partial discharges. The results are significant for use in the design and technological production development, evaluating the operability of newly developed or improved materials of the corona protection system.