The large scale penetration of non-synchronous generation based power electronics converters interfaces in current power systems is modifying their dynamic characteristics. The observation, monitoring and supervision of the electromechanical oscillation changes due to this integration is a requirement in order to protect the system from undesired events. This paper uses the Prony analysis to estimate the critical modes by using the tie-lines which interconnect the operative areas as measurement points and evaluating the impact of the
