This paper presents an integrated optimal power flow with phase shifter approach to enhance power system reliability, availability, loss optimization & system security. Overloading of sub system in a power system sometimes may pose stability issues, which may lead to unwanted Outages & Blackouts, equipment failure which will result long repair replacement cycle, cost of repair and heavy revenue losses. Under these conditions, to ensure economical and reliable operation of the grid, power through the lines should be controlled within their limits. To control power flow phase shifting transformer (PST) is one of the cheaper option. The application of phase shifting transformer will control the real power flow in transmission lines. To realize a variable phase angle shift, on load tap changers could be deployed to vary the control voltage there by change in the resultant phase angle. Simulation of One of the cases for Uttar Pradesh Network is described in this paper. The simulation work of network justifies the application of PST.