The description of the EMTDC program, the method of modeling electrical networks, and the advanced features of the EMTDC program are described in the first chapter. The advanced features of the EMTDC program are the interpolation algorithm, the algorithm for removing numerical oscillations, the extrapolation algorithm, and the ideal branch algorithm. The second chapter describes the PSCAD program package, which represents a graphical user interface for the EMTDC program. PSCAD provides us with the ability to graphically construct the tested electrical and control circuits, run the simulation itself, and graphically display the simulation results. Each element of the system is displayed with the corresponding component located in the main library and which is copied from there to the project where it represents a component instance. The user enters the component parameters, and if necessary, can also change the component definition itself. To define transmission lines and cables, we use the transmission line and cable properties editor, in which we select one of the three available transmission line models and define the characteristics of the conductor and insulation, as well as the transmission corridor itself. In the third chapter, we describe the application of the PSCAD program package and concentrate on the propagation of voltage and current waves along transmission lines and cables. We calculate the transmission and reflection coefficients of waves when the wave impedance of the medium through which the waves propagate changes and compare the obtained numerical simulation results with the analytically calculated values. We have shown a way to model a surge arrester which, thanks to the property of voltage-dependent resistance, protects devices from excessive currents. The last example shows a lightning strike to the top of a transmission line tower and the voltage distribution along the tower.