Croatian power system dynamic security before and after reconnection of the 1st and 2nd UCTE synchronous zones

The paper deals with the research concerning the security of the Croatian system before and after reconnection of the 1^st and 2^nd UCTE synchronous zones. The multimachine dynamic model used was validated by comparing simulation results with measurements obtained during reconnection of the 1^st and 2^nd UCTE zones. Various simulation scenarios of large disturbances in neighboring systems were investigated for the system state before and after reconnection. Selected results of one study case are presented and discussed. Power flow and bus frequency and voltage dynamics was analyzed and compared for the cases before and after reconnection. Prony analysis is used for signal processing. Visual comparison of time domain signals as well as quantitative indices of dominant oscillation modes clearly show that the dynamic security of the Croatian system is much better after reconnection.