An Enhancement Method for the Compensation of Voltage Sag / Swell and Harmonics by Dynamic Voltage Restorer

Now a days, the problem of voltage sags and Swells create a severe impact on sensitive loads in industries . Due to which load shedding and over voltages might occur. Several custom power devices can be used to overcome this problem. Of these power devices Dynamic Voltage Restorer (DVR) is one of the most reliable and efficient custom power devices used in power distribution network. This paper describes DVR principles and voltage compensation methods for balanced / unbalanced voltage sags and swells in a distribution system. Several methods can be included in the DVR system to overcome the voltage sag and swell. Here we use dqo algorithm. There are two important parts in the DVR one is to detect the voltage disturbance and the other is to compensate it as fast as possible. Simulation results were presented to illustrate and understand the performances of DVR under voltage sags/swells conditions. The results obtained by simulation using MATLAB confirmed the effectiveness of this device in compensating voltage sags and swells with very fast response (relative to voltage sag/swell time).