Voltage stability is a critical issue in the secure operation of the restructured power system. Poor voltage conditions lead not only to voltage collapse in the system but can also induce oscillatory instability that may cause a loss of synchronism. A critical question is how to estimate the distance to voltage instability given the present state of the system.

"Presenting the continuation and bifurcation-based approaches to assess power system voltage stability, this self-contained manual first provides basic definitions related to voltage stability based on IEEE/CIGRE voltage stability classification. Then the need for robust numerical techniques that are needed to address various aspects of voltage instability is articulated. It presents a tutorial introduction to the basic concepts in bifurcation theory and continuation methods. These methods lead to robust numerical techniques for voltage stability study. The book also provides details related to continuation power flow. In addition, it provides the approach to trace voltage stability boundary for changing system conditions and proposes a uniformed framework that provides computational approaches for both short-term and long-term voltage stability phenomena. TOC:Introduction.- Numerical Bifurcation Techniques.- Application of Continuation Methods for Voltage Stability Assessment.- Sensitivity Analysis.- Voltage Stability Margin Boundary Tracing.- Further Extensions."

Numerical Bifurcation Techniques.- Continuation Power Flow.- Sensitivity Analysis for Voltage Stability.- Voltage Stability Margin Boundary Tracing.- Time Domain Simulation.