Reduction of a Cone-Shaped Terrain Grounding Resistance by Remote Grounding

Tall structures such as wind turbines and mobile phone base stations are often installed in remote and hilly locations to gain more power or to have line of sight to end users. Those locations are usually very rocky and characterized by a low-conductivity soil. Moreover, these locations have a higher risk of being struck by lightning due to the geographical elevation and the height of the structure. A proper grounding with low resistance of such structure is of high importance. Recent studies showed that the grounding resistance of structures located on the top of mountains can be significantly higher than the grounding resistance of the same structure located on a flat ground. One of the practical methods to decrease the low frequency grounding impedance in a soil of high resistivity is to provide remote grounding to an area of lower soil resistivity, typically located at lower altitudes. In this paper, for the first time we analyze the influence of remote grounding considering a simplified cone-shaped geometry for an elevated terrain. It is shown that the remote grounding can be used to mitigate the increased resistance at the mountaintops.