The sag is phenomenon that magnitude of load voltage temporarily decreases because of power system fault. If a certain equipment in industrial process have any trouble result from sag, it can cause utility to be charged for enormous economics loss. Therefore it need to analyze the characteristic of sag and then mitigation method for sags in distribution system in oder to increase reliability. This paper suggests a sags mitigation method with concentrating on mitigation-device interface method, especially FCL that is Fault Current Limiter. And this effect has been done using PDCAD/EMTDC computer simulation analysis.