Abstract:
Steady state voltage stability analysis is effectively used to determine a stability
margin that shows how close the current operating point of a power system to the
voltage collapse point. The energy function technique represents a powerful method to
assess voltage stability of multi-machine power systems. The sparse network
formulation of this method retains the original structure of the system network and
avoids network reduction. This permits the system loads to be modeled as they exist in
practical life. Neglecting these models may lead to misleading results; e.g. the system
appears to be stable while it is actually unstable. This paper investigates this serious
problem and shows the significant effect of load modeling on power system voltage
stability. A closed form expression of the energy function is obtained. The proposed
technique is applied to Ontario-Hydro real power system (Canada).