In this paper, using adaptive networks-based fuzzy inference systems (ANFIS), a comprehensive closed-form solution for effective length of vertical grounding rod is extracted in such a way that the two effects of ionization and dispersion are simultaneously considered. In creating the model, training data are computed from multi-conductor transmission line (MTL). As a result, via ANFIS the effective length in such soils is efficiently computed. The simulation results show that considering both effects results in a length which is greater than the one in only-dispersive soil, and less than the one in only-ionized soil. Such a result is financially very important.
