Studies of voltage stability via a nonlinear SVC control

This paper discusses voltage stability enhancement by a nonlinear SVC controller. The proposed controller is designed through direct feedback linearization (DFL) technique. The effect of the controller on voltage stability is studied through small signal stability analysis on both single-machine and multi-machine power systems. In both systems, voltage stability is lost when an unstable Hopf bifurcation is encountered. When the nonlinear SVC control is taken into account, the Hopf bifurcation can be eliminated. Voltage stability is therefore improved significantly.