Analysis, Modeling and Simulation of Dynamic Voltage Restorer (DVR) for Compensation of Voltage for sag-swell Disturbances

摘要

Dynamic voltage restorer (DVR) can provide the most commercial solution to mitigate voltage sag by injecting voltage as well as power into the system. This paper describes the effectiveness of using dynamic voltage restorers (DVRs) in order to mitigate voltage sags in power distribution systems at critical loads. The DVR is a power electronic based device that provides three-phase controllable voltage source, whose voltage vector (magnitude and angle) adds to the source voltage during sag event, to restore the load voltage to pre-sag conditions. 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 asynchronously-rotating reference frame. In fact, three independent controllers (homo polar component, d-axis component and q-axis component) have been used to tackle balanced and unbalanced voltage supplies. Simulation results using Simulink' Sim Power System Toolbox is presented to illustrate the principle and performance of a DVR operation in load voltage compensation.