Independent Power Flow Control and dynamic performance enhancement by the UPFC

The Flexible AC Transmission System (FACTS) provides a new advanced technology solution to improve the flexibility, controllability and stability of a power system. The Unified Power Flow Controller (UPFC), as an outstanding part one for regulating power flow among the FACTS, can control respectively transmission line real power, reactive power and node voltage. This paper investigates dynamic performance of the UPFC for power flow control with a series of step changes in rapid succession under power system steady state and the response of the UPFC to a transmission line faults. Simulation was performed using MATLAB's Simulink SimPowerSystems toolbox and the results, which are carried out on a 5 bus test system and 4 bus multi-machine electric power system, shows clearly the effectiveness and viability of UPFC in rapid response and independent control of real and reactive power flow, and oscillation damping.