Impact of long-distance power transits on the dynamic security of large interconnected power systems

In this paper, results of several case studies applying small signal stability analysis to the European UCTE/CENTREL interconnected power system and two test networks are presented. It is shown, that the impact of long-distance power transits on the damping of interarea modes depends on the orientation of the power transits to the nodes and antinodes in the corresponding rotor mode shapes. Transits from generators located in antinode areas to nodes may improve the damping. Transits from node to antinode may worsen the damping. The described rules can be used for prediction of the qualitative impact of power transits on the damping within online oscillatory stability assessment.