Paper Title
Effects And Mitigation Of Strong Resonance In Power Systems With Multiple PSS And Facts Controllers

The variation of power system parameters causes modal interaction within the power system modes and leads to strong resonance. The effect of this dynamic modal interaction on the oscillatory modes can affect the system stability. This paper examines the performance of these power system modes in the presence of PSS and FACTS controllers, and also provides solution to mitigate this problem. The significant modes of interest are identified using the methods of participation factors and isolated using the multi-modal decomposition. Then strong resonance is observed in complete and reduced system, during the simultaneous tuning of PSS and FACTS controllers. The reduced system is obtained by the method of perturbations, proposed by Seiranyan. The case studies are presented for the New England 10-machine 39 bus system. Index Terms- Modal interaction, strong resonance, oscillatory modes, PSS, FACTS.