A Nonlinear Voltage Stability Index based on Vector Analysis Method and Measurements of Active and Reactive Powers of Power System

This paper proposes a new voltage stability assessment method based on vector analysis method. This index extraction process relies on measurements of active and reactive powers from connected buses to the generator buses. Therefore, a limit for beginning of voltage collapse is determined based on the maximum power transfer theory. On the other hand, when the system requires load shedding, a new voltage-frequency load shedding has been employed. This load shedding makes voltage and frequency stabilities be guaranteed via clustering of all loads as allowable and unallowable, and prioritizing allowable cases. Simulation results in DIGSILENT Power Factory software on IEEE-39 bus dynamic test system demonstrate the efficiency of proposed approach with respect to other methods.