Electrical Degradation Study of Machine Winding Insulation

Modern electrical machines must be designed as rugged and flexible. The use of power electronic devices cause voltage spikes and introduce harmonics that electrically degrade the insulation of the windings in the machines. High frequency power electronic driver circuits also increase the operating temperatures, which affect the aging and breakdown properties of the machine winding insulation. High frequency pulse voltages can be used to study the impact of electrical degradation of the machine winding insulation that exists in electrical machines. Insulation materials are tested at 90% rated temperature for the material. Evaluation of the change in dielectric strength is monitored versus the aging caused by the high frequency pulse voltage. In many high voltage systems, breakdown voltage is an indication of insulation condition. Partial discharge presents issues in electromagnetic compatibility as a noise source. Therefore, breakdown test and partial discharge inception/extinction voltage test at 60 Hz is performed on the twisted wire samples.