Voltage sag mitigation using multilevel inverter based distribution static compensator (DSTATCOM) in low voltage distribution system

Among the different disturbances affecting the power quality, the voltage sag are considered as a most important power quality problem faced by utilities, industrial consumer & equipment like PLC (Programmable Logic Controller), ASD (Adjustable Speed Drives) which need to be fully investigated. Custom power device are effective means for mitigating the voltage related issues prominently voltage sag, unbalanced load voltage, voltage regulation, sag/ swell etc. by compensating the reactive power with the injection of shunt current. Various DSTATCOM topologies & control scheme are suggested in the literature. In this paper by using three level H-bridge topology & five level cascaded multilevel inverter based DSTATCOM the voltage sag is compensated effectively with reduced total harmonic distortion (THD).