Estimation of residual life in electrical insulation

In the recent past, many attempts have been made for designing optimal stresses on electrical insulation for long service lives. The more important concept is the aspect of remaining life or the residual life. Prediction of residual life requires considerable knowledge of the processes leading to insulation degradation. The remaining life or the integrity of insulation at any point in time can be determined by destructive test methods and to a lesser degree of accuracy using diagnostic methods (nondestructive methods). The work covered in this paper details a method of arriving at the remaining life of mica based epoxy insulation used in rotating machines based on diagnostic testing. The authors believe that it might be possible to extend this procedure to other types of dielectric systems as well, provided conditions explained in the paper are adhered to