Design and Simulation of Dynamic Voltage Restorer (DVR) for Power Quality Improvement

Power quality is one of the main issues faced in the present era. The power quality issues such as voltage sags, swells, harmonics, and unbalance as well as the impact on sensitive loads are often occurred in any power distribution system. In order to solve the issues, one of the devices called the Dynamic Voltage Restorer (DVR) is installed, which is the most recommended custom power devices due to its size, economical features, and reliable compensation capability. However, the existing methods of control algorithm for DVR are found to be complicated, which would be causing computational burden to the controller. Therefore, in this paper, a new simplified control algorithm of DVR is proposed to solve the issues such as voltage sags, swells, harmonics and unbalances which regulates the load terminal voltage at the point of common coupling (PCC). The proposed new simplified control algorithm of DVR is based on synchronous rotating frame (SRF) and phase-locked loop (PLL) which is able to regulate the voltage at load terminals against any issues in the power supply side. In this research, a simulation work is performed by using MATLAB/Simulink with the help of Sim Power System toolboxes. The performance of the new simplified control algorithm for DVR in a three-phase system is tested under voltage sags, swells, harmonics and unbalances conditions. From this work, it is concluded that the proposed new simplified control algorithm for DVR which installed in a three-phase power distribution system is able to eliminate the voltage sags, swells and unbalances conditions and, for harmonics condition, it is able to remove or keep the harmonic contents within the acceptable level.