Optimal branch numbering for UPFC benefit study

With the development of smart grid, power electronic control devices, such as Flexible AC Transmission Systems (FACTS), are introduced into power systems. They can help system operators control the real and reactive power flow and regulate local voltage. Placing Unified Power Flow Controller (UPFC), one of FACTS devices, at certain congested locations of power system, can help alleviate system congestion, and therefore reduce production cost. The number (name) of branches can significantly affect the speed of the algorithm to find the optimal location to place UPFC. Previously, this problem was not paid sufficient attention to. In this paper, sensitivity analysis of the production cost is studied. Based on the sensitivity, the algorithm of optimal branch numbering is proposed. Simulation results on IEEE 300 system presents that by renumbering the branches, the efficiency of genetic algorithm to find the optimal location of UPFC can be greatly improved.