Abstract
This paper describes the operation effect of FACTS devices in the Korean power system. At the year of 2010, three FACTS devices is under commercial operation in the Seoul area. Among them, 345kV ${\pm}100MVA$ STATCOM at Mi-Geum substation and 345kV ${\pm}200MVA$ SVC at Dong-Seoul substation are very close at their electrical and geographical distance. Therefore, the additional analysis including interaction and mutual transient is necessary. Therefore, a detailed EMTDC/PSCAD simulation model was developed and steady-state/transient analysis was implemented.