Nasseh - Esfahan Regional Electric Company Esfahan – Iran
Farzad - Esfahan Regional Electric Company Esfahan – Iran

There is not a certain scientific and exact method for calculation of tower footing resistance of reinforced concrete foundation towers in the grounding design branch of electrical engineering. And the few existing methods are not, by no means, of considerable mathematical and scientific value. This paper is to present a particular calculating method which the reinforcing cage of each stub, itself is a part of grounding system of the tower and contributes in reducing the tower footing resistance. The method proposed in this paper throught the exact determination of the role and contribution of the reinforced concrete foundation in the grounding system of tower reduce the expenditures of grounding system, and saves the extra expences of ground system of those towers which their foundations suffices in obtaining the desired (required) resistance. The suggested method simulates each of the reinforced foundation with a standard ground electric (a metal hemishere) and determines the exact self and mutual resistance of this electrodes and as first step yields some general relationships and formulaes for computing footing resistance and in next step determines the equivalent electrical circuit of such ground system & finally a powerfull personal computer calculates add these computations with remarkably high speed and precision.