直流入地电流经交流电网分流计算模型的简化及算法分析  

Model Simplication and Calculation Method Analysis About the Shunt of DC Grounding Current Via AC Grid

作　　者：任志超[1] 吴广宁[1] 甄威[2] 吴超[1] 张一坤[1] 

机构地区：[1]西南交通大学电气工程学院,成都610031 [2]四川电力科学研究院,成都610072

出　　处：《高电压技术》2011年第4期1008-1014,共7页High Voltage Engineering

基　　金：中加国际科技合作基金项目(2009DFA72230)~~

摘　　要：直流入地电流经交流电网分流的计算过程复杂,涉及到大范围地质分层结构。旨在简化计算模型,指出直流地电位分布与直流地电流分流的关系。首先分析了土层结构的Hummel法简化及其对地电位分布的影响;其次,研究了直流地电位分布规律及地电流分流特性;最后,讨论了直流通路等效电阻的构成,得出了直流地电位的计算方法。研究结果表明:当站点距离接地极较远时,土层简化可用于直流地电位计算;直流地电位在接地网附近小范围内会发生畸变,交流输电线的存在导致相连站点间的直流地电位差减小;接地极入地电流及复杂大地分层电阻可等效为电压源及电源内阻,在求解等效电压源电动势时,可利用贝塞尔函数的衰减余弦等价式取代无穷级数。The calculation about the shunt of DC grounding current via AC grid is a complex process, involving a large range of geological hierarchical structure. To simplify the calculation model so as to put forward the relationship of the DC earth potential distribution and the shunt of DC grounding current, firstly, we analyzed the Hummel method by applying soil-layer structure simplification and its impact to the grounding potential distribution; secondly, we studied the law of the DC earth potential distribution and the characteristic of the shunt of DC grounding current; finally, we discussed the composition of equivalent resistance in the DC Pathway, and put forward the calcula- tion method of DC earth potential. The results show that： the method of simplification layer can be adopted to calculate DC earth potential when the distance between substaions and DC grounding electrode is far enough. The distortion will occur nearby the grounding network in a small range, and the existence of AC transmission line will decrease the difference value of DC earth potential between the connected sites. The grounding current into the earth and complicated earth stratified resistant can be equivalent to the voltage source and power internal resistance. While solving the electromotive force of equivalence voltage source, attenuation cosine equivalent form of Bessel function can replace infinite progression.

关 键 词：直流入地电流分流 直流地电位分布 土层结构 Hummel法 等效电阻 贝塞尔函数 

分 类 号：TM862[电气工程—高电压与绝缘技术]