基于接地模拟试验的块状土壤影响研究

Influence Study of Massive Soil Based on Grounding Simulation Test

针对部分地区变电站建设导致的大范围土壤变化,研究这种块状土壤结构较大时产生的跨步电压二次峰值现象,解决其可能带来的问题并寻找应对措施。笔者首先运用CDEGS软件仿真还原了块状土壤面积较大时产生的这种现象,指出了其成因;并在均匀土壤结构下仿真计算了块状土壤范围、电阻率、深度等参量对这种二次峰值现象的影响;同时考虑到土壤层次化的结构特征,以200倍地网尺寸的大面积块状土壤模拟了层状土壤,衡量了层状土壤结构的存在对二次峰值的影响;在此基础上通过接地模拟试验对该现象进行了深入的探讨。结果表明:与块状土壤直接接触的上层土壤对跨步电压二次峰值影响较大,深层次土壤对跨步电压二次峰值的影响则相对较小,且土壤厚度比电阻率影响更小;实际工程中可以通过扩大施工动土范围、处理回填土壤来应对跨步电压二次峰值问题,成果具有一定的实际意义。

As for the large-scale soil changes caused by substation construction in some areas,the author carried to study the secondary peak phenomenon of the step voltage when the massive soil structure is large,and to solve the possible problems and find countermeasures. CDEGS software is used to simulate the phenomenon caused when the massive soil structure is larger,and the cause is pointed out. The influence of range,resistivity and depth of the massive soil on the secondary peak phenomenon are simulated under the uniform soil structure;Taking into account the structural characteristics of the soil layered,the simulation calculation of the large-area massive soil with the 200-time grounding grid size is carried out to simulate layered soil,and measure the influence of the existence of the layered soil structure on the peak. On this basis,the phenomenon is thoroughly discussed through grounding simulation test. The results show that the upper soil,which directly in contact with the massive soil,has a greater influence on the secondary peak of the step voltage,and the influence of the deeper soil on the secondary peak of the step voltage is relatively small. Moreover,the soil thickness has less influence than the resistivity;In practical engineering,it is possible to cope with the secondary peak problems of step voltage by expanding the construction grounding range and treating the backfilled soil,which has certain practical significance.