Research on Calculation Method for Step Voltage Limitation of DC Grounding Electrode Based on Surface High-Resistance Covering

doi:10.11930/j.issn.1004-9649.2017.02.150.07

Abstract

Abstract: In order to guarantee the human safety near the DC grounding electrode, the requirement of step voltage limit must be satisfied in grounding design. Based on the horizontal double-ring DC grounding electrode, the computation method of step voltage limit is studied under the condition of covering the ground surface of grounding electrode with high-resistance layer, and a new computational formula is given. And then the grounding characteristics under different soil conditions is analyzed by using the boundary element method. The investigation results show that the surface high-resistance covering can greatly improve the tolerance limit of the step voltage for human body. The thickness of high-resistance layer is suggested to be 10~20 cm. In order to substantially improve the tolerance limit, the resistivity of high-resistance covering is better to be greater than 1 000 Ω·m. It is also shown that the surface high-resistance covering has little influences on the grounding resistance, ground potential rise, step voltage and distribution of leakage current, and its influence on the metallic facilities can also be neglected.

Key words: DC grounding electrode, surface high-resistance covering, soil resistivity, step voltage, numerical analysis

CLC Number:

TM834

YANG Jian, PAN Wenxia, SUN Honghang. Research on Calculation Method for Step Voltage Limitation of DC Grounding Electrode Based on Surface High-Resistance Covering[J]. Electric Power, 2017, 50(2): 150-156.

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URL: https://www.electricpower.com.cn/EN/10.11930/j.issn.1004-9649.2017.02.150.07

https://www.electricpower.com.cn/EN/Y2017/V50/I2/150

References

[1] 周浩. 特高压交直流输电技术[M]. 杭州：浙江大学出版社,2014：3-23.
[2] 马为民,杨志栋,李亚男. ±800 kV 特高压直流输电工程共用接地极的可靠性评价[J]. 高电压技术,2012,36（2）：301-305.
MA Weimin, YANG Zhidong, LI Yanan. Reliability assessment on comment electrode sharing of ±800 kV UHVDC project [J]. High Voltage Engineering, 2010, 36(2): 301-305.
[3] 曹林. 高压直流输电接地极系统优化设计研究[D]. 北京：清华大学,2004：1-15.
[4] ZOU J, LIU Y Q, YUAN J S, et al . Analysis of the toroidal HVDC grounding systems in horizontal multilayer soils[J]. IEEE Transactions on Magnetics, 2006, 42(4): 1435-1438.
[5] 张晓,尹晗,何金良,等. 以降低跨步电压为目标的直流多环接地极电流配比的优化[J]. 高电压技术,2012,38（5）：1217-1224.
ZHANG Xiao, YIN Han, HE Jinliang, et al . Decreasing step voltage by optimizing current distribution proportion of multi-ring DC ground electrode[J]. High Voltage Engineering, 2012, 38(5):1217-1224.
[6] 何金良,尹晗,张晓,等. 地中敷设绝缘层降低直流接地极跨步电压的方法研究[J]. 高电压技术,2014,40（7）：1940-1947.
HE Jinliang, YIN Han, ZHANG Xiao, et al . Method of reducing DC grounding electrode step voltage based on underground insulating layers [J]. High Voltage Engineering, 2014, 40(7):1940-1947.
[7] 张云,张波,陈伟军,等. 接地系统地面高阻层的特性[J]. 高电压技术,2015,41（5）：1582-1588.
ZHANG Yun, ZHANG Bo, CHEN Weijun, et al . Characteristic of surface high-resistance coverings in grounding system[J]. High Voltage Engineering, 2015, 41(5): 1582-1588.
[8] 孙为民,何金良,曹嵘,等. 季节因素对发变电站地表高阻层安全效果的影响[J]. 中国电力,2000,33（1）：62-64.
SUN Weimin, HE Jinliang, CAO Rong, et al . Influence of seasonal factor on safety of ground surface high resistivity layer in substations [J]. Electric Power, 2000, 33(1): 62-64.
[9] 陆继明,肖冬,毛承雄,等. 直流输电接地极对地表电位分布的影响[J]. 高电压技术,2006,32（9）：55-58.
LU Jiming, XIAO Dong, MAO Chengxiong, et al . Analysis of effects of DC earthed pole on earth surface potential distributions[J]. High Voltage Engineering, 2006, 32(9): 55-58.
[10] 陈水明,施广德,赵智大. 圆环形直流输电接地极电流场分析[J]. 高电压技术,1994,20（1）：3-7.
CHEN Shuiming, SHI Guangde, ZHAO Zhida. Analysisof current field near ring-type HVDC ground electrodes[J]. High Voltage Engineering, 1994, 20(1): 3-7.
[11] 魏敏敏,曹保江,任志超,等. 地形结构及参数对特高压直流电流散流特性的影响分析[J]. 高电压技术,2012,38（2）：414-420.
WEI Minmin, CAO Baojiang, REN Zhichao, et al . Influence of terrian structure and parameter on the divergence character of UHVDC grounding current[J]. High Voltage Engineering, 2012, 38(2): 414-420.
[12] 陈凡,饶宏,李岩,等. 结合矩量法和边界元法的综合接地算法研究[J]. 高电压技术,2012,38（3）：729-736.
CHEN Fan, RAO Hong, LI Yan, et al . Numerical analysis method combining method of moments and boundary element method on grounding calculation[J]. High Voltage Engineering,2012, 38(3): 729-736.
[13] 郭剑,邹军,何金良,等. 水平分层土壤中点电流源格林函数的递推算法[J]. 中国电机工程学报,2004,24（7）：105-109.
GUO Jian, ZOU Jun, HE Jinliang, et al . Recursive method to obtain analysis expressions of green’s functions in multi-layer soil by computer[J]. Proceedings of the CSEE, 2004, 24(7): 101-105
[14] 潘卓洪,张露,谭波,等. 水平层状土壤接地问题的理论推导与数值分析[J]. 高电压技术,2011,37（4）：860-866.
PAN Zhuohong, ZHANG Lu, TAN Bo, et al . The oretical derivation and numerical analysis for grounding computation of horizontal multi-layer soil [J]. High Voltage Technology, 2001, 37(4): 860-866.
[15] 张波,崔翔. 复镜像法中的一种自适应采样方法[J]. 华北电力大学学报,2002,39（4）：1-4.
ZHANG Bo, CUI Xiang. A self-adaptation sampling scheme in complex image method[J]. Journal of North China Electric Power University, 2002, 29(4): 1-4.
[16] 解广润. 电力系统接地技术[M]. 北京：中国电力出版社,1991.
[17] 刘振亚. 特高压直流输电技术研究成果专辑. 2008年[M]. 北京：中国电力出版社,2009：53-60.
[18] 高压直流输电大地返回运行系统设计技术规定：DL/T 5224—2005[S].
[19] THAPAR B, GEREZ V, KEJRIWAL H. Reduction factor for the ground resistance of the foot in substation yards[J]. IEEE Transactions on Power Delivery, 1994, 9(1): 360-368.
[20] 陈水明,施广德,赵智大. 直流输电大地回流对地下金属管道的影响分析[J]. 浙江大学学报,1993,27（3）：315-323.
CHEN Shuiming, SHI Guangde, ZHAO Zhida. Analysis of effects of HVDC earth-return current on underground metallic pipeline[J]. Journal of Zhejiang University, 1993, 27(3): 315-323.