USE OF POWER SYSTEM STABILIZERS IN MODERN POWER SYSTEMS

Abstract

Great effort has been devoted in Power System field all over world for the analysis of dynamic stability, and in particular on the problems associated with undamped or poorly damped oscillations;. Such oscillations in multimachine systems have been observed in normal operation, especially in some cases of low frequency modes as in the case of longitudinally structured systems and as tie-line oscillations. Such oscillations are not common to all large power systems 9 but they are vertually certain to occur however, whenever operat-ing conditions conducive to them exist and then they may cause severe threat to system security and create operating problems..