Surface corona suppression in high voltage stator winding end turns

This paper presents the research aid development results on surface corona suppression systems in high voltage large generator stator winding end turns. Theoretical analysis on the physical phenomena of the surface corona in stator end turns is described. The important physical parameters of surface corona suppression systems are discussed. It is shown that at least four physical parameters of a voltage grading system should be considered and optimized to provide the reliable function both at the testing and operation conditions. Based on the theoretical analysis and practical experiments, several designs of such corona suppression systems are developed. More than 1000 practical test results show that these systems are able to suppress surface corona at over 150% to 200% of operated line to ground voltages.