Examination on Partial Discharge Characteristics and Frequency Acceleration Equivalence till Breakdown for Nanocomposite Enamel Wire

This paper presents partial discharge characteristics and film thickness wear till dielectric breakdown under bipolar repetitive impulse voltage application to twisted pair enamel wire added with nano-size boehmite to polyimide (PI) resin by comparing with a sample without the addition. The frequency acceleration equivalence of the life time and PD characteristics till breakdown is also examined. As a result, it was found that at frequencies 10 kHz to 30 kHz, a frequency acceleration equivalence held in terms of the total amount of PD charge at an applied voltage Va = 1.5 kV, while it did not at Va = 3.0 kV due to severer heat generated by PD. In addition, it was found that the coating thickness erosion of boehmite PI was less likely to be caused than that of neat PI under the same experimental conditions. Consequently, it is indicated that the total PD charge amount is closely related with the coating erosion speed.