Research on aging state detection of reactor turn-to-turn insulation under high-frequency square wave voltage excitation

In power electronic equipment, magnetic devices are important parts, and their working condition and reliability are closely related to turn-to-turn insulation. With the increasing application of high-frequency square wave voltage in the fields of frequency conversion technology and motor control, the high voltage stress on magnetic devices will accelerate insulation aging, so it is necessary to monitor the aging state of turn-to-turn insulation. At present, researchers mainly detect insulation aging by detecting partial discharge signal. However, this method cannot realize the early monitoring of aging, and the measurement cost is high and the accuracy is low. Therefore, for the dry-type core reactor with epoxy resin as the insulation medium, this paper proposes a turn-to-turn insulation aging state detection method under high-frequency square wave voltage excitation. According to the relationship between the turn-to-turn insulation aging state of the reactor and its parasitic capacitance, the turn-to-turn insulation aging degree of the reactor is predicted by measuring and analyzing the phase information of high-frequency components of the current signal. Finally, the measuring principle and method are introduced and verified by experiments.