Enhanced grounding system impedance measurements for high-voltage substations

A new practical approach to the shifted frequency method for grounding impedance measurements of high-voltage substation is presented in this paper. The results obtained by the proposed method are compared with the corresponding results obtained by the transition method as well as by the heavy-current injection method. It is shown that the proposed approach gives an accurate assessment of the grounding impedance in the presence of power frequency interference. This method is easy to implement.