Article,
Enhancement of Power Quality Problem by Using Dynamic Voltage Restorer
International Journal of Innovative Research in Advanced Engineering, 1 (6): 400-407 (July 2014)
Abstract
Dynamic voltage restorers (DVRs) are used to protect sensitive loads from the effects of voltage sags on the distribution feeder. This paper presents and verifies a novel voltage sag detection technique for use in conjunction with the main control system of a DVR. In all cases it is necessary for the DVR control system to not only detect the start and end of a voltage sag but also to determine the sag depth and any associated phase shift. The DVR, which is placed in series with a sensitive load, must be able to respond quickly to a voltage sag if end users of sensitive equipment are to experience no voltage sag. The DVR can restore the load voltage within few milliseconds. A control technique based on a proportional–integral (PI) controller and a selective controller is used. The controller is designed in a synchronously-rotating reference frame. In fact, three independent controllers have been used to tackle balanced and unbalanced voltage supplies. Simulation results using ‘MATLAB SIMULINK’ Sim Power System Toolbox is presented to illustrate the principle and performance of a DVR operation in load voltage compensation
