首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3篇
  免费   0篇
电工技术   3篇
  2002年   1篇
  1998年   2篇
排序方式: 共有3条查询结果,搜索用时 328 毫秒
1
1.
This paper presents experimental data and calculations concerning the electrical properties of positive streamers in mineral oil at large gaps and HV. The experiments concern the measurement of charge, electric field, and the determination of the potential drop along streamers, either in the liquid alone, or for streamers guided within insulating tubes. Calculations of charge and field distribution around streamers are carried out by charge simulation. To do this, streamers are represented by objects with simple shapes (spheres or cylinders) equivalent to their macroscopic aspect. These models lead to a correct agreement with measured streamer charge and field on the plane electrode. Qualitative correlations are established between calculated field distributions and streamer behavior such as velocity, transitions between propagation modes. It is also concluded that the potential drop in streamers and branching both act as regulating mechanisms that help to keep the streamer tip field, and hence the velocity, constant over a wide voltage range  相似文献   
2.
This paper presents an experimental study of positive streamer propagation in mineral oil, in large point-plane gaps under impulse voltage. A systematic investigation was done concerning the influence of gap distance (⩽35 cm), and voltage from streamer inception up to large overvoltages. The measurements presented concern breakdown voltage measurements, time to breakdown, visualization of streamers (streak and still photographs), electrical measurements (transient current, charge), light emission intensity. Streamers are characterized and then classified into different modes (2nd, 3rd and 4th modes) according to their propagation velocities up to more than 100 km/s. According to the applied voltage, transitions between modes are observed, and correlations are established between charge, shape, and streamer velocity. The physical mechanisms as well as practical consequences are then discussed  相似文献   
3.
Presents a study of streamer propagation in transformer oil, with point-plane and semi-uniform geometry. The latter is made of parallel plane electrodes, with a thin triggering point of calibrated size. By reducing the length of the point, it is possible to move progressively from a point-plane geometry to a quasi uniform geometry. The propagation of streamers is impeded by the presence of a metallic plane behind the triggering point, that reduces the field on propagating streamers. The effect varies widely according to the streamer type considered. The propagation of negative and fast positive streamers is nearly quenched, whereas slower filamentary positive streamers (usually responsible for breakdown in oil) are less affected. This shows that many results obtained in point-plane geometry can not be simply extrapolated to the more realistic case of uniform field  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号