Non Symmetrical Ground Grid Design Technique for Elevated Metro Station-A Case Study

摘要

This paper describes the design of earthing conductor, electrode positioning of unsymmetrical earthing system for an elevated metro station. The technique depends upon determination of electric field intensity around the earthing system and distribution of current injected into the soil. The electric field intensity is determined by charge simulation method. Two layer soil model is adopted as per IEEE 80:2000 standard for the analysis. The procedure provides accurate voltage profile for determining touch and step potential. It is found that unsymmetrical earth grid is superior over symmetrical earth grid. Simulation study is done on MATLAB/Simulink R2014b and ETAP 6.0. The obtained result is verified by comparing the analytically obtained data with numerical method. The theoretical findings can be useful for practical implementation in any metro station.