Voltage stability assessment in the presence of optimally placed D-FACTS devices

Distributed Flexible AC Transmission System (D-FACTS) devices offer many potential benefits to power system operations. This paper presents a novel strategy for the application of D-FACTS devices in controlling system voltage. The impact of installing D-FACTS devices is examined by studying the sensitivities of voltage magnitude with respect to line impedance. Sensitivities enable us to determine the potential benefits of the D-FACTS Devices offered to the system. Most appropriate locations to install D-FACTS devices for controlling system voltages are also determined. In this paper, steady state model of recently introduced D-FACTS device DSSC is incorporated in voltage stability assessment of an interconnected power system in terms of its reduced equivalent two-bus integrated system. The participation of a particular bus in global voltage instability is assessed in terms of global voltage stability index (GVSI). It has also been used to assess the global voltage stable state of the network. The proposed methodology has been applied under simulated condition on IEEE 30-bus test system.