Mitigation of voltage sag and swell using dynamic voltage restorer

The fast developments in power electronic technology have made it possible to mitigate voltage disturbances in power system. Among the voltage disturbances challenging the industry, the voltage sags are considered the most important problem to the sensitive loads. Dynamic voltage restorer (DVR) is a series connected power electronic based device that can quickly mitigate the voltage sags in the system and restore the load voltage to the prefault value. DVR is recognized to be the best effective solution to overcome this problem. The primary advantage of the DVR is keeping the users always on-line with high quality constant voltage maintaining the continuity of production. In this paper, the usefulness of including DVR in distribution system for the purpose of voltage sag and swell mitigation is described. The DVR presented here is based on the concept of dqo. The proposed control method is found very efficient for detecting and clearing any power quality disturbance in distribution systems. Results of simulation using Matlab-Simulink are demonstrated to prove the usefulness of this scheme.