坡面分层土壤模型下地网接地电阻测量方法研究

Research on the Measurement Method of Grounding Grid Resistance in Sloping-Layered Soil Area

一般水电站所建山区地形复杂,土壤分层近似坡面分层,此时采用传统三极补偿法测量地网接地电阻会出现较大误差。运用CDEGS软件建立坡面分层的土壤模型,并通过仿真分析研究测量引线铺设方向对该模型下地网接地电阻测量值的影响,并将所得测量引线最佳铺设方案运用到某实际水电站地网接地电阻测量中,验证了其具有一定的普适性。研究结果表明,坡面分层土壤模型下,若采用30°夹角法测量地网接地电阻,应使两条测量引线夹角的角平分线与土壤地表分界线平行布置,且电压极靠近地表分界线时接地电阻测量值误差最小。

Hydropower station is usually built in the moun-tainous area of complex terrains,where soil is approximately sloping layered. In this case,the measurement result of the grounding grid resistance may have a large error if we use the traditional three-electrode compensation method. With Canadian SES'CDEGS software,this paper establishes a sloping-layered soil model according to the actual terrain of one hydropower station,then calculates the value of the grounding grid resis-tance and analyzes the effects of laying directions of measuring lead wires on the hydropower station grounding grid resistance through simulation. The results show that if 30° angle method is applied to measure the grounding grid resistance, the best measurement scheme of making minimum error is to lay the angle bisector of the two measuring lead wires parallel to the boundary of soil surface,and to make the voltage electrode closer to the surface boundary.