The correct coordination of the electrical protections of a synchronous generators is a difficult task, especially those based on impedance. Usually, these protections are set according to the recommendations of the main standards and manufacturer guides. However, the validation of the settings is difficult to obtain, since there is no commissioning test to evaluate the correct selectivity. In this paper, the use of SIMSEM power-system simulation software is proposed to evaluate the settings of a turbogenerator. Firstly, three electrical protections based on impedance characteristics are described. Secondly, a case study is presented with some simulations results. Finally, the advantages of using this procedure in the engineering process of power plants.