Impulse characteristics of grounding devices considering soil ionization by the p-order time domain difference method

Knowledge of the impulse characteristics of grounding devices is important for the lightning protection of power system. In this paper, the transient model in time domain of grounding grid is established by the electrical network theory. Then, the p-order differential algorithm is applied to solve electrical network model. To consider the soil ionization phenomenon, the soil discharge equivalent model is established and solved by iterative solution algorithm. The (3 similar to 5)-order TDDM could eliminate partial zigzag oscillations of the response voltage calculated by the 1-order TDDM and improve calculation efficiency simultaneously. Finally, the full-scale experiments of typical grounding devices are carried out which verifies that the calculation errors are <5.14 %.