Dielectric frequency response analysis applied to stator winding insulation systems

Abstract

This study presents the results of investigations that were performed to verify if the use of low-voltage dielectric frequency response analysis can be successfully applied to detect the deterioration of stator winding insulation systems. For the main investigation, three newly manufactured stator coils with a rated voltage of 13.8 kV were aged using the thermal cycle testing procedures described in IEEE 1310 and an extended and modified version of voltage endurance testing described in IEEE 1553, until dielectric failure. Throughout the accelerated ageing process, several dielectric measurements were performed, and the results trended over time. The results of the dielectric frequency response measurements were then compared with conventional dissipation factor measurements and partial discharge measurements to assess the sensitivity of dielectric frequency response analysis applied to stator insulation. This study also discusses the effects of the nonlinear end-potential grading material on the measured dielectric losses. Additional experiments are summarized to illustrate how this nonlinear material behaves depending on the applied voltage level and frequency. The conclusions of the investigation are also extended, and the principles applied to measurements on complete stator windings, installed in the field.

Date	4 Apr 2024
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Éric David (Supervisor)