Analysis and modeling of UPFC: A comparison between power injection model and voltage source model

The interconnected systems are equipped with Flexible AC transmission Systems (FACTS) for better control on power transfer capability and stability improvement. The operation of these devices can be explained with different modeling techniques. Unified Power Flow Controller (UPFC) is one of the FACTS device with multivariable control capability. Different load flow models have been investigated to study the impact of UPFC in load flow solution. Power injection model and voltage source based model of UPFC are used for study the effect of UPFC in an interconnected system. So this paper focuses on the performance analysis and comparison of these UPFC models in a standard IEEE 5 bus system.