芦潮港-嵊泗直流工程预选极址的接地极计算和分析

Calculation and Analysis on Buried Electrode in Luchaogang-Shengsi HVDC Project

以芦潮港－ 嵊泗跨海直流供电工程中的接地极为例，计算和分析了在多层介质中的直流接地极的本体溢流分布，介质中的电流密度、场强、电位的分布以及跨步电压、接地电阻和安全距离等．结果表明，沿接地极方向的值比垂直于接地极方向大．所以从管道的安全距离方面考虑，接地极沿海岸线布置较有利，而且接地极本体的端部溢流值很大，为使接地装置在整体上均匀消耗，宜按溢流倍数相应加粗．计算中应用了点匹配法、镜像法和金属管道的传输线等值模型方法，并对传输线等值模型法进行了改进．

The distributions of current field, voltage and field intensity of HVDC buried electrode in multi layer soils were calculated and analyzed when considering the factor of voltage distribution along the surface of electrode. The ground resistance and safety distance of underground metallic pipeline from the buried electrode were also presented. The study shows that the disperse current density in the extremity of ground electrode is up to 1.99 times of that in the middle, so the extremity should be thickened. The current and potential field stresses in the direction of ground electrode are severe than that of the other directions, so the ground electrode had better be buried in the vertical direction of the buried metallic pipelines. The paper combined the point match method, mirror method and the improved transmission line type of equivalent model of metallic pipelines to get good results.