Fitting algorithm for power tower grounding resistance with vertical layered soil model

The accurate algorithm, which is used in the calculation of tower grounding resistance of power line in vertical layered soil, is difficult for normal engineering personnel to handle. Based on Green function, the resistance of typical tower grounding device is calculated. Therefore, the fitting function, which represents the relationship between resistivity of vertical layered soil and resistance values of grounding device, is deduced with the hyperbolic function as a fitting function using the least squares curve fitting methods. At last, the fitting formula of tower grounding resistance with the vertical layered soil model is acquired. According to the precision analysis, it is found that the accuracy of proposed formula is related with the initial value, but its maximum error does not exceed 10%.