Aging State of Stator Bar Insulation Based on the Entropy Weight and Dielectric Response Methods

This article describes a novel research method for evaluating the aging state of the primary insulation material of large generator stator bars based on combining dielectric response methods with the entropy weight method. Vacuum pressure impregnation (VPI) epoxy-mica insulation specimens subjected to different electrical aging time periods were characterized via frequency domain spectroscopy (FDS), polarization and depolarization current (PDC), and thermal stimulated depolarization current (TSDC) tests. The comprehensive characteristic (VPI) parameters obtained by calculating the characteristic dielectric response parameters using the entropy weight method were used to describe the aging state of the VPI epoxy-mica insulation. The results show that during electrical aging, microcosmic structural variations within the insulation directly manifested as changes in the characteristic dielectric response parameters and indirectly affected the comprehensive evaluation parameters of the entropy weight method.