Lately there has been a change in the approach towards in energy sector, it is getting each more important, that producing of electrical energy should be clean, enviromental-friendly and sustainable. One of the solutions of this problem is the usage of renewable energy sources. Wind power led all technologies in new power generation in 2015. The record number of GW of wind power installed in 2015, bringing the total installed global capacity to 433 GW at the end of 2015. Nevertheless these equipments have some disadvantages. One of them is the quite big probablity of a lightning sturck in the tower due to the installation boundary and the design of these buildings. This problem is more than it seems, the installation of an appropriate grounding system is difficult and expensive, because the basement of the towers are mostly installed under the seabed or on mountain ridges. My aim with writing this thesis was to modeling the potential circumstances, calculating the touch and step voltages when a wind turbine tower is strucked by lightning, as the Diplom planning 1 and Diplom planning 2 subjects of the MSc course was. My final goal was creating an appropriate grounding consideration, whose grounding resistance is allowed in the concerning standards, but it is simpler than the already used solutions. The first Chapter of my thesis is about the lightning. The second Chapter described the gorunding resistance and it’s measuring methods. In the third Chapter you can observe the grounding system of a wind turbine. In the fourth Chapter the meaning of touch and step voltage and the concerning standards are demonstrated. The fifth Chapter is about the skin effect. In the sixth Chapter is the indtroduction of the CDEGS software. The seventh Chapter is about a simulation by CDEGS software of quasistationer and transient potential circumstances, touch and step voltages. In the eightth Chapter the results are analysed. In the nineth Chapter the the grounding solution is improved and analysed. In the tenth Chapter, final part the results are analysed.