Generator Stator Winding Stress Grading Coating Problem

This TB based on a questionnaire on the industry's experience with stress-grading degradation of stator endwinding in hydropower generators, verified that this deterioration is not uncommon and often occurs a few years after commissioning. This leads to life reduction of winding and ozone generation. Standard technical specifications and testing procedures are not available yet. This TB describes experts' experiences for inspection, maintenance and testing of the endwindings in factory and on complete stator windings.