纵向磁场下中频真空电弧的重燃现象分析  

Re-Ignition of Intermediate Frequency Vacuum Arc at Axial Magnetic Field

作　　者：蒋原 李擎[1] 崔家瑞[1] 武建文[2] 贾博文[2] Jiang Yuan;Li Qing;Cui Jiarui;Wu Jianwen;Jia Bowen(Key Laboratory of Knowledge Automation for Industrial Processes of Ministry of Education School of Automation and Electrical Engineering University of Science and Technology Beijing,Beijing 100083 China;School of Automation Science and Electrical Engineering Beihang University,Beijing 100083 China)

机构地区：[1]北京科技大学自动化学院工业过程知识自动化教育部重点实验室,北京100083 [2]北京航空航天大学自动化科学与电气工程学院,北京100083

出　　处：《电工技术学报》2020年第18期3860-3868,共9页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金面上项目(51677002);中国博士后科学基金项目(2018M631307);中央高校基本科研业务费项目(FRF-TP-19-035A1)资助。

摘　　要：中频供电系统已在航空电源中得到广泛应用。根据实验结果,电流开断能力从360Hz时的22.4kA下降至850Hz时的14.0kA。该文研究纵向磁场下360~850Hz真空电弧开断失败时的重燃现象。由Mayr模型的最小二乘法解可知,发生击穿时电弧能量衰减的时间加长,这是不利于电流开断的。一方面,随着电流频率的增加,相对小的电流值就会使电流过零时的变化率di/dt达到开断阈值;另一方面,频率提高会增强涡流效应,导致纵向磁场过零后的剩余磁感应强度和滞后相位增加,阻碍过零后等离子体扩散。实验中发现,电弧重燃点总出现在触头边缘处,计算表明触头边缘处的电场强度集中、电流密度高,进而导致场致发射的概率增大。此外利用帧差法分析电弧图像,估算得到金属液滴的运动喷射速度为10~20m/s。电流过零后金属液滴的消失时间大于中频电流半个周波时间,金属液滴的存在是引起电弧重燃的因素。Intermediate frequency(IF,360-800Hz)power supply system has been widely used in more-electric aircrafts.The IF current interruption ability decreases from 22.4kA/360Hz to 14.0kA/850Hz according to the experimental results.In this paper,post-arc re-ignition of IF vacuum arc in axial magnetic field(AMF)is studied.By the solution of the Mayr arc model,the decay time of arc energy is prolonged when re-ignition happens,which goes against current interruption.With the increase of frequency,a small current will cause the change rate of current di/dt to reach the threshold at the time of zero-crossing.In addition,the eddy effect is enhanced,resulting in the increase of the residual magnetic induction intensity and hysteresis phase of AMF.It is found that the re-ignition position in IF vacuum arc always appears first at the margin of contacts.As shown by ANSYS calculation,the electric field at the margin is stronger and the current density is higher,thereby increasing the probability of field emission.By analyzing the arc images,the velocity of metal particles is about 10~20m/s and the dissipation time of the metal particles is longer than the arc time,which may cause the IF vacuum arc re-ignition.

关 键 词：中频真空电弧 纵向磁场 电弧重燃 涡流效应 场致发射 

分 类 号：TM561[电气工程—电器]