土壤介电频变特性试验研究及其对接地极冲击特性的影响  

Experimental Study on the Frequency Characteristic of Soil Permittivity and the Influence on Impact Characteristics of Grounding Electrode

作　　者：司马文霞[1] 艾琳丰[1] 袁涛[1] 杨庆[1] 朱彬[1] 唐妍 

机构地区：[1]输配电装备及系统安全与新技术国家重点实验室(重庆大学),重庆市沙坪坝区400044

出　　处：《中国电机工程学报》2015年第16期4247-4253,共7页Proceedings of the CSEE

基　　金：国家重点基础研究发展计划项目(973项目)(2009CB724504);国家自然科学基金项目(51107153)~~

摘　　要：接地系统是维护电力系统安全可靠运行的重要基础设备。从频域介电谱理论出发,开展了土壤频变特性的研究。为了降低电极极化效应影响,配制了含水量较高、电阻率较低的土壤样品。然后进行了不同含水量、不同含石量的土壤介电谱的测量,对测得的数据进行函数拟合并代入有限元冲击特性模型中进行计算,分析了土壤电气参数的频变特性对冲击接地性能的影响。结果表明:冲击电流作用下,接地极周围土壤的介电常数随频率在低频段近似符合幂函数规律,在高频段近似符合指数函数规律;在同一频率点,土壤的介电常数随土石比例和含水量的降低而减小;考虑土壤介电常数频变特性后,冲击电流作用下接地极暂态电阻值与介电常数恒定时相比有显著的差异。Grounding system is an important foundation to maintain safe and reliable operation of power system equipment. In this paper, the frequency characteristics of soil were studied by the frequency domain dielectric spectroscopy theory. To reduce the effects of electrode polarization, the soil samples with high water content and low resistivity were mixed. Then the soil dielectric spectrum with different water contents and amounts of rock was measured, and the data were fitted to mathematical functions. Then the function was merged into the finite element model to calculate the impact characteristics and the influence of the frequency variability of soil electrical parameters on the impact characteristics of grounding electrode was analyzed. The results show that the relationship between the dielectric constant and frequency is the power function within the low frequency and the exponential function in high frequency. At the same frequency, the dielectric constant of soil decreases with decreasing soil-stone ratio and water content. Considering the frequency characteristics of soil permittivity, the transient grounding resistance value under impulse current is very different from that calculated with constant permittivity.

关 键 词：土壤 冲击接地 介电谱 频变特性 有限元方法 

分 类 号：TM853[电气工程—高电压与绝缘技术]