Mixed-integer method for optimal UPFC placement based on line flow-based equations

Flexible AC transmission systems (FACTS) is an evolving technology, which can be used to improve power system utilisation. Determining the type, location, device number, and device compensation are critical to successfully utilizing FACTS controllers, and this paper presents a method of Unified Power Flow Controller (UPFC) placement, which is capable of simultaneously determining number of UPFCs, their location(s), and minimum compensation to maximise the system loadability. A mixed integer linear programming approach is considered, and the method utilises line flow based equations to formulate the problem. The method is successfully demonstrated on the IEEE 9-bus and IEEE 30-bus test systems.