The penetration of power electronics in large-scale interconnected power systems has significantly increased in the recent years. As a consequence, the electromechanical inter-area modes are no longer the majority of modes which involve distant dynamic (modeled by differential equations) devices , i.e., of coupling modes. In this paper we develop a new methodology which allows one to determine all the coupling modes (modes related to classic synchronous generators with large inertia, modes related to power electronics (Power Park Modules) of a given power system. To this end, we excite the system with wellchosen temporal signals and analyse the correlation between the obtained outputs. This leads to the identification of classes of coupled dynamic devices of the grid. Next, a selective modal analysis method is applied to each class to determine good approximations of coupling modes which involve the devices of the class. Finally, iterative search of eigenvalues initialized at the approached values of the coupling modes found at the previous stage lead to exact values of the eigenvalues of the overall power system. The proposed methodology is applied on the 23 machines model of the Spain-France interconnection.

The interconnected European power system is evolving due to the new extensions and to the systematic integration of Power Park Modules, i.e., unit or ensemble of units generation electricity (Renewable Energy (RE), Distributed Generation (DG), etc), which is connected to the grid by power electronics and FACTS (STATCOM, HVDC,...). As a consequence, the increase of the size and the emergence of the new oscillatory modes which involve distant dynamic devices, i.e., of coupling modes (modes associated to generator/turbine inertia, and modes associated to Power Park Modules), and of modes related to various regulations. In this paper, a full scan of European power system is given. An exhaustive method that determines all oscillatory modes independently of the system's order, of the topology and without a priori knowledge about the system, is used. The exhaustive method is fully analytic. Indeed, it is based only on the state-space realisation of any given power system and does not require operator manipulation like dynamic simulations. To this end, we quantify and analyse the interaction between the different inputs/outputs of a given system. This leads to the identification of classes of coupled dynamic devices of the power system. Next, starting from a reduced number of classes, a selective modal analysis method is applied to each class to put into evidence a good approximation of all oscillatory modes. Finally, a complete classification of the oscillatory modes found at the previous stage is provided in terms of the types (interarea, electrical, ...) and their characteristics (oscillation frequency, damping, participation, ...). 2900 oscillatory modes were found for the studied model of the European system. Index Terms-coupling/inter-area modes, European power system, dynamic reference model, large-scale systems, modal analysis.

No abstract