摘要
超特高压直流输电系统单极大地运行时,直流电流经过接地极在地中形成恒定电场,对周围电力设施、环境产生一定的影响,且极址附近大范围复杂土壤结构是影响地中电流散流的主要因素。因此本文建立考虑大范围复杂土壤结构的直流接地极有限元数值计算模型;其中针对数千米的求解区域和接地极0.04 m的截面半径之间存在105数量级差异导致的剖分奇异问题,引入"薄壳"理论;根据地下暗河及断裂层等实际情况构建含有水平层状、垂直层状的土壤结构,分析接地极在异阻层状土壤处于不同位置及环境土壤电阻率不同时的散流性能。得出结论:水平层状对接地电阻的影响较大,垂直层状异阻区能明显改变地表电位,在垂直层远离接地极的一侧电位梯度变化平缓,适合埋设金属管道或建设电力变电站。
When the UHVDC transmission system operates in a single pole,a constant current field is formed in the depth of ten km in the center of the earth.A large area of complex soil structure near the pole is the main factor affecting the current in the ground.The constant current field theory considering the large complex soil structure simulation model based on grounding;lead to large differences in the numerical calculation of finite element method in solving a wide range of areas and the grounding conductor section size split singular problems,the introduction of"shell"theory;in addition,the vertical construction of underground with horizontal layered soil to study the structure of earthing electrode in bulk flow resistance properties of the layered soil.Finally,the model calculation and analysis of the DC grounding electrode site near the complex soil structure on the impact of current distribution and draw the conclusion:whether based on vertical different resistance layer soil is high resistivity or low resistivity in the vertical grounding layer away from one side of the potential gradient varies smoothly for buried metal pipeline or construction of electric power substation.
作者
李景丽
栗超超
冯鹏
LIJingli;LI Chaochao;FENG Peng(School of Electrical Engineering,Zhengzhou University,Zhengzhou 450001,China;Institute of Industrial Technology,Zhengzhou University,Zhengzhou 450001,China)
出处
《电瓷避雷器》
CAS
北大核心
2020年第2期1-9,共9页
Insulators and Surge Arresters
基金
国家自然科学基金(编号:51307152)。
关键词
高压直流输电
直流接地极
土壤结构
薄壳理论
有限元法
high voltage DC transmission
DC grounding
soil structure
theory of thin shell
finite element method
