Impact of the StatCom on the power system feasibility region boundary

A feasibility region of a power system is defined by all operating points that can be reached by continuous variation of parameters without causing system´s instability. The boundary of this region is composed by bifurcation surfaces. When surfaces associated to Hopf bifurcations intersect each other, emerges a 2-degenerated Hopf point producing the appearance of a unstable hole inside the feasibility region that was supposed continuously stable. This paper study the effect of using a Flexible AC Transmission System (FACTS) device, named StatCom, on the topological characteristic of the feasibility region. This study is carry out by a multi-parameter bifurcation analysis. The controller is used to damp out Hopf bifurcations, such that the unstable hole inside feasibility region disappears. The study is carried out in a 3-nodes power system, and the controller effect is quantified by comparing the feasibility region geometric topology when the StatCom connected to the system with respect to the results obtained when the controller is not used.