Effectiveness of Dynamic Voltage Restorer for Unbalance Voltage Mitigation and Voltage Profile Improvement in Secondary Distribution System

To make a secondary distribution system operate at its optimal performance, the use of an advanced power custom power device known as dynamic voltage restorer (DVR) has been proposed and researched. Optimum performance means acceptable voltage profile, increased reliability of supply, no overloading of cables and distribution transformers, the absence of unbalances in both voltage and current phases, and acceptable loss. This study involves the effective mitigation of power quality disturbance in secondary distribution networks as a result of voltage variation and voltage imbalance using a very effective power electronics-based custom power controller known as DVR. A DVR is connected between the secondary distribution transformer and the customer load along a feeder with a radial arrangement. An innovative new design-model of the DVR has been proposed and developed using dq0 controller and the proportional integral controller method. Model simulations were carried out using MATLAB/Simulink in Sim Power System tool box. The simulation results attest to the optimal performance of the proposed DVR configuration in mitigating the power quality problems, correcting voltage unbalance, and enhancing the voltage profile at the customer side to a statutory limit of ±5.