脉冲电压下SF6气体放电极性效应研究

项目名称： 脉冲电压下SF6气体放电极性效应研究

项目编号： No.51507066

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 电工技术

项目作者： 冉慧娟

作者单位： 华北电力大学（保定）

项目金额： 21万元

中文摘要： 高电压等级VFTO对全封闭组合电器（GIS）的绝缘危害较大，SF6是GIS的主要绝缘介质。当出现不均匀电场时， SF6的绝缘特性急剧下降。设备在加工过程中不可避免的存在毛刺或残留一定的金属导电微粒，使得VFTO下极不均匀场中SF6的放电特性引发关注。极性效应是极不均匀场中气体放电特性研究的热点之一。研究表明，当脉冲作用时间较短时，极性效应会出现反常现象。目前国内外关于极不均匀场下SF6放电极性效应的研究还相当匮乏，研究结论并不一致，对于极性反常现象形成机理的认识也不够透彻，均有待进一步的深入研究。因为VFTO的上升沿为纳秒量级，因此，VFTO下SF6的放电特性研究可以借鉴纳秒脉冲下的一些研究数据。综上所述，本课题不仅有助于补充脉冲电压下电介质绝缘特性的研究数据，丰富和完善气体放电理论，而且能够为VFTO下GIS的的绝缘设计提供部分参考依据，研究工作具有重要的理论价值和实际意义。

中文关键词： 气体放电；气体击穿；放电特性；放电机理；放电过程

英文摘要： Very Fast Transient Overvoltages (VFTO) may result in insulation failures inside or outside Gas Insulated Switchgears (GIS), especially in higher voltage levels. In GIS, the sulfur hexafluoride (SF6) is used as the main insulation medium due to its excellent insulating properties. However, the dielectric strength of SF6 is very sensitive to field nonuniformity. Hence, in practice, the electrical breakdown strength of compressed SF6 can be greatly reduced due to local field enhancement. However, protrusions, surface roughness and presence of conducting particles can not be avoided during the process of equipment manufacturing. So the investigation about discharge characteristics in highly nonuniform electric field of SF6 has been attracted much attention..Polarity effect is one of the research hotsports about discharge characteristics in highly nonuniform electric field. Research shows that the polarity effect under nonuniform electric field appears abnormal phenomenon when the duration of applied pulse being shorter. But up to now, the research on polarity effect of SF6 discharge is rather scarce at home and abroad, and the research conclusions are not consistent. Also the understanding about the formation mechanism of polarity reversal phenomenon is not thorough, and all the work remains to be further in-depth study..Due to the rise time of VFTO’s wavefront being very short, usually within dozens of nanoseconds, the research data about the gas discharge characteristics of SF6 under nanosecond pulse can be drawn lessons by the research under VFTO. So the study on polarity effect of SF6 discharge under pulses, not only is helpful to supplement the research data about the dielectric insulation properties, enrich and perfect the theory of gas discharge under pulses, but also can provide some references for the insulation design of GIS under VFTO. So the research work has important theoretical value and practical significance.

英文关键词： gas discharge;gas breakdown;discharge characteristic;discharge mechanism;discharge process