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. This paper presents a comprehensive review on the research and developments in the power
system stability enhancement using FACTS damping controllers. Several technical issues related to FACTS
installations have been highlighted and performance comparison of different FACTS controllers has been discussed.
In addition, some of the utility experience, real-world installations, and semiconductor technology development have
been reviewed and summarized. Applications of FACTS to other power system studies have also been discussed.
About two hundred twenty seven research publications have been classified and appended for a quick reference.
Key words: power system stability, PSS, FACTS, SVC, TCSC, TCPS, STATCOM, SSSC, UPFC, IPFC