Dynamic Stability Improvement of Multi Machine Power System

Abstract: As Power systems become more interconnected, analysis of dynamic performance of such systems become very important. Due to its increasing complexity, the stabilization of system is recent interest of area. Power system mostly subjected to low frequency oscillations due to disturbances. The stability analysis of synchronous generator under small disturbances is examined for multi machine system. The multi-machine system is predominant in inter area mode oscillations. These disturbances occur due to large reactive power, weak ties or large AVR gain with low time constant. The main function of AVR is to maintain constant terminal voltage of Generator and hence improving transient stability. However, it produces negative damping to the system which leads to electromechanical oscillations. To overcome the effect of negative damping, a supplementary control loop is provided by Power system stabilizers. The PSS can increase the damping of the system and transmission capability. Conventional Power system stabilizers (CPSS) is widely used for enhancing system stability, but CPSS design can�t guarantee its performances under heavy loading conditions.

Keywords: stability analysis, automatic voltage regulator (AVR), power system stabilizer (PSS), convention power stabilizers (CPSS).