In this paper, a new developed steady-state model of the UPFC is proposed. The proposed model consists of one shunt compensation block and two series compensation blocks. In this case, the UPFC with the new model will be investigated when it is installed in multi-machine systems with non-linear load model. In addition, the steady–state performance of the new model operating as impedance compensation will be presented and compared with that obtained from the original Gyugyi model.