雷电冲击下极不均匀电场中SF_6/N_2混合气体的协同现象  

Synergistic Phenomenon of SF_6/N_2 Gas Mixtures in Non-uniform Electric Field Under Lightning Impulse

作　　者：郭璨[1] 张乔根[1] 文韬[1] 李志兵[2] 游浩洋 秦逸帆 

机构地区：[1]西安交通大学电气工程学院,西安710049 [2]中国电力科学研究院,北京100192

出　　处：《高电压技术》2016年第2期635-641,共7页High Voltage Engineering

基　　金：国家电网公司科技项目(编号略)~~

摘　　要：近年来在气体绝缘金属封闭输电线路(GIL)中开始逐步使用低SF6混合比的SF6/N2混合气体作为绝缘介质,用以替代纯SF6气体。为了在电力设备中更好地应用SF6/N2混合气体,在极不均匀电场、正负两种极性雷电冲击(LI)下,通过实验分析研究了较低SF6混合比的SF6/N2混合气体的放电特性与协同现象,并在负极性雷电冲击下发现了反常的负协同效应。研究发现:负极性雷电冲击下,N2的击穿电压随气压的升高趋势显著高于SF6与SF6/N2混合气体,当气压超过0.3 MPa后,N2的击穿电压明显高于SF6/N2混合气体,甚至在0.5 MPa时超过了纯SF6的击穿电压,即出现了显著的负协同效应,且随着气压的升高,负协同效应明显增强;正极性下仍存在一定的协同效应,但协同效应随着气压降低而减弱,当气压低至0.2 MPa,亦出现了负协同效应。In recent years, the SF6/N2 gas mixtures with low SF6 mixing ratio are increasingly applied as insulating medium in gas-insulated metal-enclosed transmission line in order to replace pure SF6. In order to better apply SF6/N2 gas mixtures in power equipment, we studied the breakdown characteristics and synergistic phenomenon of SF6/N2 gas mix- tures with low SF6 mixing ratio in non-uniform electric field under positive and negative lightning impulse, and the negative synergistic effect was found under negative lightning impulse. The research indicates that the breakdown voltage of N2 increases more significantly than that of SF6 and SFdN2 gas mixtures with increase of gas pressure under negative lightning impulse. When the gas pressure exceeds 0.3 MPa, the breakdown voltage of N2 is significantly higher than that of SF6/N2 gas mixtures, and the voltage even exceeds the value of pure SF6 at 0.5 MPa. The results show that the negative synergistic effect appears and becomes more significant with increase of gas pressure under negative lightning impulse. On the other hand, the synergistic effect is weakened with decrease of gas pressure under positive lightning impulse, and it turns to be negatixie synergistic effect at 0.2 MPa.

关 键 词：雷电冲击 极不均匀电场 SF6 N2 混合气体 负协同效应 先导过程 流注过程 

分 类 号：TM863[电气工程—高电压与绝缘技术]