This article presents the results and conclusions of steady state, voltage and small signal stability studies applied to the electrical power systems of Ecuador, Colombia and Panama, for finding weaknesses and strengths on the future electrical integration. The analyses were performed using the NEPLAN software for 2008 maximum demand scenarios, year in which the three countries are expected to be interconnected according to the Colombian electrical planning studies. The modal analysis used in the study has more advantage than the time domain methods for the power systems planning. The modal techniques obtain the critical modes and their participation factors applied in different ways to voltage stability and small signal stability studies