Selection of Global Input Signals for Wide-area PSS to Damp Inter-area Oscillations in Multi-machine Power Systems

A method is proposed in this paper to select the global input signals for Wide-area PSS to damp inter-area oscillations in large power systems. By analyzing the observability of interarea mode, the two important concepts of dominated mode and group are connected with each other. And according to two-group mutual oscillating feature and unit coherency characteristic of inter-area oscillation, the inertia and observability synthetic index is proposed. Then, studies are carried out on a testing system where using the index to select the optimal global input signals for Wide-area PSS to damp the inter-area oscillations, the effectiveness of the index is validated through time domain simulation and eigenvalue analysis.