A Novel Approach for comprehensive modeling of Grounding System of HV Towers Using Vector Fitting Method

In past, the grounding systems usually were modeled by an individual Resistor. This estimation is useful only at low frequencies, while in high frequencies, the inductance of grounding system plays the main role to identify the phase and amplitude of that. In recent years, as wind farms grow rapidly throughout the world, the grounding system and ground impedance of wind turbine towers under transients have got more important. As a matter of fact, an exact model to testify dynamic properties of grounding system should represent nonlinear effects of soil ionization and be frequency dependent. Some new researches conducted in this issue, all are based circuit theory which does not allow for accurate analysis of aforementioned behaviors. This paper has come to express a new approach to model any grounding system only by few RLC branches in wide frequency range. A new model and some simple formula that is recommended in this paper, represent all effects of transient phenomena of lightning strikes and all analysis have got more easier than other approach. Then the outputs or the RLC branches are implemented in EMTP and get analyzed. So it’s possible to evaluate power systems under lightning strikes with presence of precise behavior of grounding systems.