IEEE Working Group Report of Problems with Hydrogenerator Thermoset Stator Windings Part I-Analysis of Survey

Various modes of premature failure of hydrogenerator stator insulation systems have been noted and the Working Group survey results are presented. Failure modes are correlated with salient features of the insulation system and of the generator. The results may be used to improve the design and maintenance of stator insulation systems. The paper forms the basis for two companion papers: Part II-Detection, Correction and Prevention; and Part III-Bibliography.