Simplified equations for mesh and step voltages in an AC substation

A large number of grounding grids in substations have shapes other than a square or a rectangle, whereas the simplified formulas for mesh and step voltages available in the literature are derived for square or rectangular grids. Improvements in the simplified equations for determining mesh and step voltages are presented. With the modified simple equations, mesh and step voltages at a substation of any practical shape can be estimated with reasonable accuracy. The results obtained with the improved equations have been compared with accurate results obtained via computer. The error in the values obtained with the derived equations is within 16% for mesh voltage and less than 30% for step voltage