On the Effect of Pulse Voltage Frequency during Insulation Electrical Endurance Tests at 200 Mbar Pressure

For aerospace applications, DC bus voltages reaching several kilovolts pose significant threats to the reliability of electrical machines (EMs) due to partial discharge issues. Extensive research has been focused on the insulation endurance under partial discharge erosion, and impulse voltage frequency has been identified as a primary factor influencing insulation lifetime. Moreover, compared to other industrial applications, the insulation systems for aerospace EMs are also subject to pressure effects. Therefore, four electrical aging test groups with varying frequencies (i.e., 10,20,25, and 30 kHz) are conducted in a low-pressure environment (200 mbar). Time-tofailure data are quantitatively analyzed, and the relationship between insulation lifetime and impulse voltage frequency is preliminary modelled for low-pressure conditions. Based on the experimental study, it is found that frequency significantly impacts insulation lifetime at 200 mbar, and a linear relationship appears to be appropriate for modeling the insulation lifetime with respect to impulse voltage frequency.