Analytical Expressions for the Resistance of Rodbeds and of Combined Grounding Systems in Nonuniform Soil

The modifications are suggested of Schwarz's formulas for the resistance of rodbeds and for the mutual resistance of grid and rodbed component parts of the combined grounding systems which enable the application at nonuniform , two - layer soils. These expressions , together with a formerly derived formula for grid resistances, provide the necessary tools for evaluating the resistance of combined grounding systems. A simple empirical formula for the practical assessment of this resistance is also given.