Abstract:The unified power flow controller (UPFC) can optimize power flow distribution of power grid and improve transmission capacity of the system. In actual application,the change of system reliability index after UPFC is accessed is an important factor to be considered in UPFC access solution. Aiming at the unbalanced distribution of power flow in Anhui power grid with the continuous expansion of grid scale,the application scheme of double - circuit UPFC structure in Anhui power grid is proposed and its necessity is demonstrated. Then,the reliability model of double - circuit UPFC elements is established. Based on Monte Carlo simulation and optimal load reduction,the reliability evaluation algorithm of power grid with double - circuit UPFC is written. Finally,based on the actual data of power grid,the influence of UPFC access on system reliability is analyzed,and the ability of UPFC application scheme to improve power grid reliability is verified.