Reliable Power Flow Control in Parallel Transmission Lines Based on UPFC

The UPFC is one of the most versatile topologies of the FACTS family. The UPFC can be decomposed in two different power circuits: the parallel one maintains the network bus voltage by consuming or producing reactive power, and the series one controls the active and reactive power flow through the insertion of a series voltage in transmission line. The aim of the present paper is to investigate in details the power quality and the dynamic performance of the control PI for the UPFC in order to improve the stability of the power system hence providing security under increased power flow conditions. The results demonstrate that the control PI is very effective in improving the transient power system stability.