AVRs and PSSs revisited

In this paper a conceptual analysis on the effect of Automatic Voltage Regulators (AVR) and Power System Stabilizers (PSS) for small signal stability (SSS) of power systems is developed. A modal formulation approach including the use of the Participation Matrix is used. The Modal Formulation is performed considering synchronous generator (SG) equations for both the Electromotive Forces (EMF) model and the Flux Linkages (FL) model as well as AVR and PSS equations. Then, a selected study case is evaluated to study the effect of the AVR and PSS on the small signal stability. For pedagogical purposes a comparison between the basic RLC circuit and a synchronous generator connected to an infinite bus, to clarify the concepts of synchronizing torque and damping torque, is presented.