面向多电飞机的脉冲波形下局部放电规律

为满足多电飞机（MEA）的大功率用电需求，系统工作电压需要进一步提高，而较高电压会增加相关部件的绝缘失效风险。面向多电飞机特定工作场景和参数，搭建了模拟飞机电作动器中的绕组间绝缘故障测试平台，开展了1 kHz范围内的局部放电（PD）大量重复实验，研究了特定电压幅值、正弦波和方波脉冲波形下局部放电幅值、放电重复率和放电相位等统计特征，并计算评估了不同频率值下多电飞机中的局部放电行为。实验结果表明：在设定频域范围内，方波脉冲下的起始放电电压（PDIV）都低于正弦，方波脉冲波形对绝缘影响更大；随着频率升高，放电幅值逐渐降低，但放电重复率几乎呈线性增长；放电时刻集中于上升沿/下降沿末端。以50 Hz作为对比基准频率，1 kHz时的放电幅值降低80%，而放电重复率增加11.92倍，较高频率下多次累积的小幅值击穿成为威胁绝缘失效的主要原因。计算分析认为高频下空间电荷场强变化导致的放电延迟时间减少和周期数目增加分别导致局部放电脉冲幅值降低和放电重复率增加。本实验结果有助于针对多电飞机电气系统和相关装备开展针对性绝缘测试和评估，并有望为多电飞机向大功率高电压方向的设计提供参考和借鉴。

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.