The FACTS known as flexible ac transmission systems devices are solid state converters designed on voltage source converter and now the approach of engineers towards planning and operations of power systems by the implementation of FACTS devices. In this thesis work, UPFC FACTS controller models have been developed to reduce transmission losses and to improve voltage profile with power flow algorithm and models have been linearised by Newton’s method using a minimum of iterative steps. This paper describes the implementation of the UPFC Flexible AC Transmission Systems (FACTS) devices optimally locate in IEEE 14 bus system for power flow analysis to reduce the transmission losses and improve the voltage profile. In this thesis, UPFC is placed at every load bus at every transmission line to obtain the result of minimum power losses and minimum voltage deviation.