Unified power flow controller (UPFC): its versatility in handling power flow and interaction with the network

At present, many studies focusing the steady-state behaviour of the UPFC, mainly in radial systems, have been carried out. However, there is a little literature examining its effect and interaction with the network. The present paper initially shows a brief analysis of both the series injected voltage and the shunt reactive current, which is based upon the dq-coordinates. Thereafter, the UPFC capability for controlling the transmittable power flow in a transmission line, where it has been implemented, and its simultaneous effect and control over an inflexible parallel line, are analysed. The simulations performed ratify the UPFC capability in increasing and modifying the power flow through a specific route. The EMTP program constituted the main tool for most of the results shown along the work.