Assignment of this master’s thesis was to describe basic features of transient lightning strike analysis in power systems, using a software package ATP-EMTP and EMTP-RV. The emphasis of the paper is on illustrative examples of lightning strikes and on modeling the elements of the power systems. The paper itself consists of several chapters where the elements of the system are described theoretically and practically modeled in a software package. The first part of this paper describes the basic features of the EMTP software package and its two versions, ATP-EMTP and EMTP-RV. It’s a software tool for the analysis of electromagnetic transients and insulation problems in high voltage technology. The ATPDraw graphics preprocessor is also described as well as various software modules like ATP Analyzer, GTPPLOT, PlotXY, WPCPlot etc. In the EMTP version, the program module EMTPWorks and ScopeView are described. The second part describes high-voltage and low-voltage surge arresters. The division of high-voltage with respect to the construction is also described, and it is about silicon-carbide and metal-oxide surge arresters. Features and characteristic values are also described. The third part deals with modeling the elements of the power systems. It is described the modeling of a 400 kV overhead line in the ATPDraw graphics preprocessor. After that, the modeling of surge arresters is described in the EMTPWorks program module where Pinceti and Giannettoni model were used. Then, the modeling of harmonized overvoltage protection was performed on the example of a family house in the ATPDraw preprocessor. In the final part of the paper, simulation and an illustrative example of a lightning strike in a substation were performed. In the first example, a lightning strike was simulated in a transmission line pole 900 m away from a 400 kV substation in ATPDraw, while in the second example a lightning strike is simulated in a power line connected to a GIS substation. The second example describes the characteristics of all used elements from the generator, which is replacement for network, via transmission line poles and overhead lines to surge arresters and busbars within the substation. The simulation results and the corresponding values are presented in the ScopeView program, on the basis of which various conclusions can be drawn.