冰冻土壤中垂直接地极的接地电阻变化规律 郭在华.doc

冰冻土壤中垂直接地极的接地电阻变化规律_郭在华.doc冰冻土壤中垂直接地极的接地电阻变化规律_郭在华
第40卷第3期:698-706 2014年3月31日
DOI: -
高电压技术
High Voltage Engineering , : 698-706
March 31, 2014
冰冻土壤中垂直接地极的接地电阻变化规律
郭在华
1,2
,邢天放
2,3
1112
,吴广宁,曹晓斌,朱军,朱泽伟
(,成都610031;,成都610225;
,杭州310008)
摘要:单根垂直接地极在均匀土壤冰冻前后工频接地电阻值的变化会影响防雷接地检测的误差和防雷接地的效果。鉴于此,利用CDEGS软件对单根垂直接地极在均匀土壤产生冻土前、后的接地电阻值R1、R2进行了仿真。分析仿真数据得出:影响该接地电阻值的主要因素有反射系数、冻土厚度和垂直接地极的长度;当垂直接地极在
冻土层时, R1与R2之间满足线性变化的关系式;当垂直接地极穿过冻土层时,R1与R2之间满足非线性变化的关系式;与CDEGS的仿真值相比,垂直接地极在冻土层时,采用提出的拟合公式得到接地电阻的相对误差在±5%左右;垂直接地极穿过冻土层时,采用提出的拟合公式得到接地电阻相对误差绝对值在5%~10%左右。关键词:冻土;垂直接地极;工频接地电阻;反射系数;冻土厚度;接地极长度
Grounding Resistance Change Rule of Vertical Grounding Electrode in Frozen Soil
GUO Zaihua, XING Tianfang, WU Guangning, CAO Xiaobin, ZHU Jun, ZHU Zewei
( of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031, China;
of Electronic Engineering, Chengdu University of Information Technology, Chengdu 610225,China;
Protection Center of Zhejiang Province, Hangzhou 310008, China)
1,2
2,3
1
1
1
2
Abstract:For a single vertical grounding electrode, its power frequency grounding resistance in homogeneous soil is different before and after soil freezing. This will affect the error of grounding resistance test as well as the effect of groun-ding measures. Therefore, through simulation in CDEGS, we calculated the grounding resistance of single vertical grounding electrode in frozen and unfrozen soil, denoted by R1 and R2, respectively. According to the results, R1 and R2 are mainly influenced by three factors, namely, the reflection coefficient, the thickness of frozen soil and the length of the vertical grounding electrode. When the electrode length is no more than the thickness of frozen soil, there is a linear rela-tionship between R1 and R2; otherwise, the relationship would be nonlinear. We proposed equations for fitting the resistance, by which we obtained