Partial discharge rule of more-electric-aircraft with pulse voltage waveform

To meet the high power demand of More-Electric-Aircraft (MEA), the system voltage needs to be increased, consequently increasing the insulation failure risk of related components. In this paper, on the basis of specific working scenarios and parameters of MEA, an experimental platform was built to simulate the insulation fault between windings in aircraft electric actuators, and several repetitive tests were conducted for partial discharge measurement within the range of 1 kHz. With sine voltage and square pulse voltage wave, the influence of frequency on Partial Discharge (PD) statistical parameters, including amplitude, repetition rate and phase, was compared and evaluated. Experimental results show that the PD Inception Voltage (PDIV) of the square pulse voltage wave is lower than that of sine wave in the specific frequency domain. With the increase of frequency, the PD amplitude decreases gradually, while the PD repetition rate increases almost linearly. The discharge is always concentrated at the end of the rising/falling edge. Compared with the values at 50 Hz, the discharge amplitude decreases by 80% and discharge repetition rate increases to 11.92 times at 1 kHz. The multiple cumulative breakdowns at a high frequency appear to be the main threat to the insulation failure. It is also unveiled that the decrease of the discharge delay time and the increase of the number of cycles resulted from the change of the space charge field intensity at a high frequency explain the decrease of the pulse amplitude and the increase of the discharge repetition rate. These experimental results contribute to the insulation testing and evaluation of related equipment in MEA, and are expected to provide reference for the design of high-power and high-voltage electric system in aircraft. © 2020, Beihang University Aerospace Knowledge Press. All right reserved.