The document describes modeling and simulation of a dynamic voltage restorer (DVR) for mitigating voltage sags and swells. A DVR is proposed as a cost-effective solution to protect sensitive loads from voltage fluctuations. The operation and equivalent circuit of a DVR are presented. Simulation results show that the DVR can satisfactorily compensate for both balanced and unbalanced voltage sags and swells, maintaining the load voltage at its nominal value.

1. Modeling And Simulation For Voltage Sags/Swells Mitigation Using Dynamic Voltage Restorer (DVR) By P. Lakshmana Rao (08FF1A0226) K. Durga Praveen (08FF1A0214) Nagulmeera (08FF1A0233) A.V.V.S. Kushal Kumar (08FF1A0261) Guided by R. Sai Srujan MANDAVA INSTITUTE OF ENGINEERING & TECHNOLOGY VIDHYA NAGAR,JAGGAIAHPET-521175 ELECTRICAL & ELECTRONICS ENGINEERING DEPARTMENT

2. Describes the problem of voltage sags and swells and its severe impact on non linear loads or sensitive loads . The dynamic voltage restorer (DVR) has become popular as a cost effective solution for the protection of sensitive loads from voltage sags and swells. The control of the compensation voltages in DVR based on dqo algorithm is discussed. ABSTRACT :

3. INTRODUCTION : A voltage sag is a short duration decrease in voltage values. short circuits (faults) on the electric power system, motor starting, customer load additions, and large load additions in the utility service area.

4. A voltage swell is a short duration increase in voltage values. By large load changes and power line switching.

5. DVR operation

6. Equivalent circuit of DVR

7. Proposed system configuration

9. Source voltage Injected voltage Load voltage Three-phase voltages sag:

10. Source voltage Injected voltage Load voltage Three-phase voltages swell:

11. The simulation shows that the DVR performance is satisfactory in mitigating voltage sags/swells. The DVR handles both balanced and unbalanced situations without any difficulties and injects the appropriate voltage component. From simulation results also show that the DVR compensates the sags/swells quickly and provides excellent voltage regulation. The supply voltage to keep the load voltage balanced and constant at the nominal value.