This paper addresses the dependability analysis of protection schemes of transmission grids using a computer simulator. Following modern protection schemes, a stochastic hybrid model has been developed in Modelica/Dymola environment. The model supports the evaluation of required dependability on the basis of suitable probability indices. A different simulation strategy has been implemented and its main features are discussed in detail. A logging tool has been created to supervise discrete events and assist in the results analyses. Furthermore, a custom simulation control panel helps to manage and to launch the simulation outside the Modelica environment.