FACTS operation scheme for enhancement of power system security

This paper presents a FACTS operation scheme to enhance the power system security. Three main generic types of FACTS devices are introduced. Line overloads are solved by controlling active power of series compensators and low voltages arc solved by controlling reactive power of shunt compensators, respectively. Especially, the combined series-shunt compensators such as UPFC are applied to solve both line congestions and low voltages simultaneously. Two kinds of indices that indicate the security level related to line flow and bus voltage are utilized in this paper. They are iteratively minimized to determine operating points of the devices for security enhancement. The sensitivity vectors of the indices are derived to determine the direction of minimum. The proposed algorithm is verified on the IEEE 57-bus system with FACTS devices in a normal condition and in a line-faulted contingency.