Convergence acceleration techniques in CAD systems for grounding analysis in layered soils

In the last years the authors have developed a numerical formulation based on the Boundary Element Method for the analysis of grounding systems embedded in uniform soils. This approach has been implemented in a CAD system that currently allows to analyze real grounding grids in real-time in personal computers. The extension of this approach for the grounding analysis in layered soils is straightforward by application of the method of images. However in some practical cases the resulting series have a poor rate of convergence; consequently, the analysis of real earthing grids in multilayer soils requires an out of range computational cost. In this paper we present a CAD system based on this BEM numerical formulation for grounding analysis in multilayer soils that include an efficient technique based on the Aitken acceleration in order to improve the rate of convergence of the involved series expansions. Finally, we show some examples by using the geometry of real grounding systems.