This paper compares three heuristic methods (SA, TS and GA) applied to the optimal location of FACTS devices in a power system. The optimizations are made on three parameters: the location of the devices, their types and their sizes. The FACTS devices are located in order to enhance the system security. Five types of FACTS controllers are modeled for steady-state studies: TCSC, TCVR, TCPST, SVC and UPFC. Simulations are performed on an IEEE 118-bus power system for several numbers of devices. Results show that the three algorithms converge to similar optimal solutions. The security margin of the system may be increased with the use of FACTS devices, but some limitations are observed. The locations of the devices and their influence areas are analyzed