Accelerated aging of high voltage machine insulation under combined thermal and electrical stresses

An attempt has been made in this study, to evaluate systematically the effects of electro-thermal aging (electrical stress from 8.0 kV/mm to 13.3 kV/mm and temperature from 70°C to 155°C) on a resin rich machine insulation system by measuring a number of electrical parameters. Results indicate that when the electric stress and temperature are both high, a breakdown of model samples is achieved very fast. The time to failure for any other situation depends upon the actual combination of electric and thermal stresses applied. The temperature developed in the system appears to play a more significant role in the deterioration of the insulation.