ABSTRACT
In this chapter, we will consider the network controllers in the formulation of SPEF. It is not feasible (without making approximations) to model HVDC lines (with converter controls) and FACTS controllers (static var compensator (SVC), thyristor-controlled series capacitor (TCSC), static synchronous compensator (STATCOM), static synchronous series compensator (SSSC), and unified power flow controller (UPFC)) in stability studies. These controllers are increasingly being applied in power systems not only for flexible system operation in steady state but also to improve the dynamic performance under small or large disturbances. The introduction of HVDC links in the system can assist the system operator during a contingency in rescheduling power flows to avoid overloading of AC lines. FACTS controllers also serve a similar purpose. In the absence of the network controllers, generation rescheduling is required to prevent overloading of lines and this would increase the operating costs as economic dispatch is normally used to minimize operating costs.
