This paper presents the development of a testbed for tuning the parameters of Power System Stabilizers (PSS). The main tuning methodology comprises the use of the classic Single Machine Infinite Bus (SMIB) model and the phase compensation method along with the modal analysis approach and the application of the Mean-Variance Mapping Optimization (MVMO) algorithm. This methodology is then improved by structuring a real-time simulation environment where the SMIB model is implemented in both PowerFactory and eMEGAsim (MAT LAB - Simulink - OPAL-RT Simulator) in order to compare the obtained results and optimize the tuning process through the implementation of additional constraints. Finally, the complete real-time testbed is monitored via CENACE's Wide Area Monitoring System (WAMS) in order to observe the dynamic performance of the power system and to ensure avoiding any instability problems in the Ecuadorian electric system due to an improper PSS field tuning.