Abstract: A Healthy power system plays very important role in transmission line, but due to non linear load it canít possible. A Power quality problem is an occurrence express as a nonstandard voltage, current or frequency that results in a failure or a mis-operation of end user equipments. There are many facts devices are used to improve power quality, such as SVS, STATCOM, TCSC, and SSSC and so on. But commonly we can use STATCOM for reduction of power quality problems, because STATCOM is used for low voltage also. Shunt connected STATCOM mainly used for enhancement voltage stability. This paper present review about overview of Power Quality problems and corrective methods.

Keywords: Power quality, STATCOM, Voltage sag, and Voltage swell.