Simulation of dynamic voltage restorer (DVR) to mitigate voltage sag during three-phase fault

Power quality in distribution system is one of the chief concerns in the modern industrial and commercial applications. Power quality problem is an occurrence manifested as a non-standard voltage, current or frequency that results in a failure of end user equipments. However critical problems in power quality have been recognized such as transients, sags, swells and harmonic distortions. Out of these sags and swells are predominantly found and have severe impact on sophisticated devices whose performance is very sensitive to the quality of power supply. To overcome this problem, custom power devices are used. One of those devices is the Dynamic Voltage Restorer (DVR), which is the most efficient and effective modern custom power device use in power distribution system. It has many advantages like lower cost, smaller size, and its fast dynamic response to the disturbance. This paper presents modeling, analysis and simulation of a Dynamic Voltage Restorer for power quality problems, voltage sag based on Sinusoidal Pulse Width Modulation (SPWM) technique using MATLAB. The analysis was applied for three phase fault without including DVR and including DVR which shows that voltage profile was improved and sag was also mitigated.