Unified Power Quality Conditioner for Dynamic Voltage Restoration And Fault Current Limitation

In recent years, power system has employed many applications of power electronics technologies for power quality improvement. Unified Power Quality Conditioner (UPQC), which consists of double converters connected by a do capacitor with each other, has great potential because of its high controllability. Various attractive applications for power quality improvement are considered but the active power handled by each converter should be exchanged simultaneously through a do link. Therefore, when one converter exchanges active power with the power system, both the other converter controller and a capacitance of the do link must be carefully designed. This paper proposes a utilization of the left-shunt UPQC for both dynamic voltage restoration and fault current limitation in order to improve power quality. The do link capacitance was designed to be suitable for the applications. Some simulation studies are introduced to prove the effectiveness of the UPQC.