Temperature Impact on Insulation Lifetime During Electrical Endurance Tests

The winding temperature is widely recognized as the primary factor contributing to insulation degradation. However, the higher DC bus voltage intended for future transportation electrical drive systems may also promote electrical aging. To ensure insulation reliability, a comprehensive understanding of insulation degradation under both electrical and thermal stress is crucial. In this study, electrical endurance tests are conducted at various temperatures to accurately determine the impact of temperature on insulation lifetime. Three test temperatures within the electrical machine thermal operating range (1550C, 170°C, and 200°C) are selected and evaluated. For each temperature, electrical endurance tests are carried out on corona-resistant wire twisted pairs, considering three voltage levels higher than the partial discharge inception voltage. Through such an extensive experimental campaign, the significant influence of temperature on both insulation lifetime and inverse power law's parameters are quantitatively analyzed.