电子注入式迁移管测量低E/N值下SF6主要分解产物迁移特性

Drift Characteristics of Typical SF6 Decomposition Products Under Lower E/N by Ion Mobility Tube with Pulse Electron Injection

采用脉冲电子注入式迁移管,对GIS中常见气体成分在低E/N值下的负离子迁移特性进行了研究,研究对象包括:O2、SO2、SOF2、SO2F2和SF6。在所研究E/N值范围内(0.264-1.168 Td),结果表明:由于避免了传统离子门迁移管技术的电荷损失问题,离子电流信号强度大为提高;所研究气体对应的负离子迁移时间与迁移场强呈线性关系,迁移距离越长,迁移时间变化率越大。采用迁移距离和迁移时间差值法计算出的离子迁移速度,能有效消除离子起始加速阶段速度不稳定对稳定迁移速度的影响。所测成分的负离子迁移率在较低迁移场强下,随着迁移场强的增加而降低,当迁移场强增大到一定值后,迁移率稳定在一与迁移场强无关的确定值;迁移场强较小时,离子热运动对迁移率结果有较大影响。

The study on anion drift characteristics of typical gas composition in GIS,under lower E/N,by ion mobility tube with pulse electron injection,has been finished.The objects of study includeO2、SO2、SOF2、SO2F2 and SF6.In the E/N range of 0.264〜1.168 Td,the results show:Because the loss of charge is avoided by ion mobility tube with pulse electron injection,the signal intensity of anion current is enhanced greatly.The drift time of negative ion of objects have good linear relation with electric field.The longer the drift distance,the larger the rate of change of drift time.The influence of speed instability during initial acceleration period can be eliminated by deviation calculation of drift distance and drift time.With the increase of drift electric field,the ion mobility of negative ion decrease at first,and then stable at a fixed value which is not changed with drift electric field.Under lower electric field,anion thermal motion has larger effect on ion mobility.