The Unified Power Flow Controller (UPFC) is a device that is capable of providing control of voltage magnitude, active and reactive power flows. This paper represents the effect of UPFC location in steady-state analysis and to demonstrate the capabilities of UPFC in controlling active and reactive power flow within any electrical network. In this paper, a complete power injection model of UPFC including both the series injection branch and the shunt exciting branch is derived in rectangular form. An injected power model method is used to represent UPFC in load flow program. Finally, different types of simulation tasks are carried out based on IEEE 30-bus test system. (C) 2004 Elsevier Ltd. All rights reserved.