Effects of STATCOM, SSSC and UPFC on voltage stability

The purpose of this paper is to study the effects of three FACTS controllers: STATCOM, SSSC and UPFC on voltage stability in power systems. Continuation power flow, with accurate model of these controllers, is used for this study. Applying saddle node bifurcation theory with the use of power system analysis toolbox (PSAT), the optimal location of these controllers are determined. Using a 6-bus test system the effects of these controllers on voltage stability are examined. It is found that these controllers significantly increase the loadability margin of power systems.