Comparison of various UPFC models for power flow control

This paper presents a comparative study on various implementation techniques of Unified Power Flow Controller (UPFC) in load flow algorithms. The comparison is done among; decoupled technique, comprehensive technique, load injection technique, π load injection technique, indirect technique, and matrix partitioning technique. The merits and demerits of these techniques are presented. Beside these techniques, the paper presents a developed UPFC model based only on current injection approach. The model is implemented in Newton-Raphson current injection load flow method (NR-CIM). This model addresses the main drawbacks of previous techniques. Test results are presented using IEEE standard systems which demonstrate the effectiveness of the developed model.