This paper presents Advancement in both flexible AC transmission lines(FACTS) and superconducting Magnetic Energy Storage Systems (SMES) technologies having some excellent performances for use in power systems, such as four quadrant control, rapid response (millisecond) , high efficiency, and high power (multi-MW). In recent years, power demand has increased substantially while the expansion of power generation and transmission has been severely limited due to limited resources and environmental restrictions. As a consequence, some transmission lines are heavily loaded and the system stability becomes a power transfer-limiting factor. Flexible AC transmission systems (FACTS) controllers have been mainly used for solving various power system steady state control problems. However, recent studies reveal that FACTS controllers could be employed to enhance power system stability in addition to their main function of power flow control. The literature shows an increasing interest in this subject for the last two decades, where the enhancement of system stability using FACTS controllers has been extensively investigated.