NOMENCLATURE

Abstract—Voltage stability margin (VSM) enhancement of a system under line outage contingencies is an important task for secured operation of large interconnected power system. This paper proposes a novel placement strategy for a unified power flow controller (UPFC), which enhances the VSM of the system. The location for the installation of UPFC is identified using voltage stability index (VSI) and the voltage change index (VCI). The proposed method has been tested under simulated conditions on a few power systems and the results of a 22-node real-life equivalent power network are presented for illustration. Index Terms—Contingency, voltage stability margin, VCI