Flexible AC Transmission Systems (FACTS) were prepared recently, using power electronics in order to control power flow, improve transient stability, inject/absorb reactive power and regulate the voltage profile. STATCOM is a shunt device of the FACTS series that could instantly deliver a reactive power and keep the voltage magnitude in the system within a safe range. Normally, this is accomplished by controlling the magnitude of the STATCOM generated voltage, and hence the flow of reactive power.