The effective length of vertical rods buried in two-layer soil subjected to lightning return strokes based on ANFIS

In this paper, an adaptive network fuzzy inference system (ANFIS) based on the Takagi-Sugeno- Kang technique is used for predicting the effective length of vertical rods buried in two-layer soils. The rods are subjected to two typical lightning return stroke currents namely first and subsequent stroke currents. To train the ANFIS approach, a number of input-output pairs are computed from the multi-conductor transmission line method. The inputs are resistivity values of the upper and lower layers, upper layer thickness and the rise time of the lightning current. After the training process is converged, the prediction of effective length is efficiently carried out in such soils. Also, the comparative study with the horizontal electrode buried in two-layer soils shows that the effective length of vertical rods is considerably less than that of the horizontal electrodes which are financially and practically important, whereas in single-layer soil they are different.