高电压技术2018，Vol.44Issue(2)：527-533,7.DOI:10.13336/j.1003-6520.hve.20180131024
冲击电压下SF6气体放电的驼峰现象及形成机理
Hump Phenomena and Mechanism of SF6 Gas Discharge Under Impulse Voltages
摘要
Abstract
The insulation accidents of gas insulated switchgear (GIS) induced by very fast transient overvoltage (VFTO) are increasingly serious in high voltage level power system.To ensure safe operation of GIS equipment,we developed the steep-fronted impulse voltage test equipment for studying the discharge characteristics and mechanisms of SF6 gas under impulse voltages.Moreover,we researched the influences of electrode radius on breakdown characteristics of the distance fixed SF6 gap and gas pressure on flashover characteristics of contaminated post insulator,and explained the differences of"hump" phenomena for SF6 gas in the prescence and absence of insulators by space charge model.It is found that the breakdown voltage of rod-plate gap and flashover voltage of contaminated insulator increase first and then decrease with increasing of gas pressure.The "hump" phenomena appear obviously,and the gas pressure when "hump" phenomena appear is between 0.2～0.3 MPa.The "hump" phenomenon of SF6 gas gap under VFTO is more obvious than that under LI.The "hump" height of contaminated insulator is more obvious than that of rod-plate gap under VFTO.The images shot by framing camera show that a dense space charge layer appears at the pressure when hump emerges,preventing development of discharge.An obvious bend appears in discharge channel.The streamer and leader arrival lines in breakdown voltage-pressure plot are obtained according to the streamer-leader breakdown criterion.The differential capacitance criterion for leader breakdown is adopted to explain "hump" phenomena rationally.关键词
气体绝缘开关设备/特快速暂态过电压/SF6气体间隙/绝缘子/“驼峰”现象/流注/先导Key words
gas insulated switchgear/VFTO/SF6 gas gap/insulator/"hump" phenomenon/streamer/leader引用本文复制引用
张璐,黄国强,吴经锋,张乔根,郭安祥,杨海龙..冲击电压下SF6气体放电的驼峰现象及形成机理[J].高电压技术,2018,44(2):527-533,7.基金项目
国家自然科学基金(51177132) （51177132）
国家电网公司科技项目(5226SX15001T).Project supported by National Natural Science Foundation of China (51177132),Science and Technology Project of SGCC(5226SX15001T). （5226SX15001T）
