This paper presents the modeling, simulation and analysis of the dynamic behavior of a fictitious 2times320 MW variable speed pump-turbine power plant including hydraulic system, electrical equipments, rotating inertias and control systems using the software SIMSEN. First, the modeling of hydraulic and electrical components of the power plant is presented. Then the pseudo continuous approximation is introduced. It consists in a simplification of the electrical part of the power plant. Thanks to this simplification, simulation time can be reduced drastically (~ factor 60). The complete and simplified models are compared by simulation and the validity of the pseudo continuous approximation is discussed. Finally two control strategies in generating mode are implemented and compared by simulation.