My thesis is written about the comparison of powerelectric-system simulators. In the beginning, there is an overview about the development of Hungary’s power transmission system in order to show the reasons behind the need of powerelectric-system simulators. I will give some examples of the available commercial simulators and list the main capabilities of the software. Then I introduce the two softwares, which I will use for the fault calculation, in fuller details. One of them is the Powerworld Company’s Powerworld Simulator, the other one is the Digsilent GmbH’s Powerfactory. The basis of the comparison is a fault calculation. In the first part of the thesis, I write about the methods of the calculation, what the program does in the background, which standards does it use and how is it implemented in the user interface. In the middle section there is an overview of the software’s developers, the main fields of use, and the user interface. After that, I introduce the system which will be the subject of the fault calculation. Because of the manual calculation and the limitations of the demo versions, the example network had to be simple enough. The calculations are made in the following part of the thesis. Firstly, the fault is calculated manually, and then by the two software. My conclusions are made by the results of the simulations and the earlier introduced models and methods. I compare the programs from the user’s point of view in the last section, to give a more personal comparison. The main goal of this is to show which program is more user-friendly or intuitive.