TABLE OF CONTENTS This chapter discusses the recent developments in steady state unbalanced three phase voltage stability analysis and control with FACTS. The objectives of this chapter are:
to review steady state voltage stability analysis methods in unbalanced three-phase power systems;
to introduce the continuation three-phase power flow technique that can be used for steady state unbalanced three-phase voltage stability analysis;
to examine the PV curves of unbalanced three-phase power systems;
to reveal the interesting phenomena of voltage stability of unbalanced three-phase power systems;
to investigate the impact of FACTS controls on voltage stability limit of unbalanced three-phase power systems.
Voltage stability has been recognized as a very important issue for operating power systems when the continuous load increase along with economic and environmental constraints has led to systems to operate close to their limits including voltage stability limit. In the past, various methodologies have been proposed for voltage stability analysis [1] [4]. Among the voltage stability analysis methods, the continuation power flow methods have been considered as one of the useful tools [5] [11]. However, in the literature only the application of the continuation power flow methods in voltage stability analysis of positive-sequence power systems has been described.
Due to the following reasons, a continuation three-phase power flow may be required: (a) there are unbalances of three-phase transmission lines in high voltage transmission networks; (b) there are unbalanced three-phase loads; (c) in addition, there are single-phase or two-phase lines in distribution networks; (d) there...
