同轴圆柱形电极下土壤冲击特性的试验研究  

Experimental Study on Soil Impulse Characteristics Surrounding Coaxial Cylindrical Electrode

作　　者：陈名铭[1] 曹晓斌[1] 杨琳[2] 吴昊[1] 张敏[1] 吴广宁[1] 

机构地区：[1]西南交通大学电气工程学院,四川省成都市610031 [2]四川电力科学研究院,四川省成都市610071

出　　处：《电网技术》2013年第8期2291-2296,共6页Power System Technology

基　　金：国家电网公司科技项目(2011-WG-4);铁道部重大专项课题(2011T008);中央高校基本科研业务费专项资金(SWJTU11CX035)~~

摘　　要：了解土壤的冲击特性是研究雷电流冲击下接地装置周围土壤火花放电现象的关键,同时也是输变电工程雷电防护的基础。通过试验研究了土壤水分含量、冲击极性等对土壤放电时延、50%冲击击穿电压和击穿场强的影响规律,并测试了不同水分含量下的土壤电阻率。试验结果表明:土壤电阻率随水分含量的增大而减小;放电时延随土壤水分含量的增大而减小;相同水分含量下,放电时延随击穿电压的增大而减小,随冲击电流波前时间的增大而增大,且负极性的放电时延比正极性大。而当土壤水分含量较低时,50%冲击击穿电压随着土壤水分含量的增大而减小,对应的击穿场强亦如此,且明显低于均匀空气击穿场强30 kV/cm,同时正极性50%冲击击穿电压比负极性低。It is the key point to understand the impulse characteristics of soil for the research on spark discharge of the soil surrounding grounding device under the impact of lightning current,and is also the foundation of lightning protection for power transmission and transformation system.The influencing regularities of soil moisture content,impulse polarity etc.on delay discharging time,50% impulse breakdown voltage and breakdown field-strength of soil are researched by experiments,and the soil resistivities under different soil moisture content are measured and tested.Experimental result show that soil resistivity decreases with the increase of soil moisture content;the delay discharging time decreases with the increase of soil moisture content;under the same soil moisture content,the delay discharging time decreases with the increase of breakdown voltage and increases with the increase of current wavefront duration and the delay discharging time under negative impulse polarity is longer than that under positive impulse polarity.Under lower soil moisture content the 50% impulse breakdown voltage decreases with the increase of soil moisture content,and so does corresponding breakdown field strength,which is evidently lower than 30 kV/cm,the breakdown field strength of air under standard temperature and pressure,and the breakdown voltage under positive impulse polarity is lower than that under negative impulse polarity.

关 键 词：土壤击穿 水分含量 放电时延 击穿电压 冲击极性 

分 类 号：TM866[电气工程—高电压与绝缘技术] TM934