Hamid Karimi - Department of Electrical Engineering, College of Engineering, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran
Mohsen Simab - Department of Electrical Engineering, College of Engineering, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran
Mehdi Nafar - Department of Electrical Engineering, College of Engineering, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran

One of the common problems of power quality is the occurrence of voltage sags due to different types of balanced and unbalanced short-circuit faults in electrical distribution systems. Dynamic Voltage Restorer (DVR) is the most effective equipment used for voltage recovery in power distribution systems and it injects voltage in series with line voltage for voltage recovery. In this paper, the structure and general components of this equipment are presented. In addition, by applying a control scheme based on Synchronous Reference Frame Theory (SRFT) in its control system, the effective role of this equipment in compensating and maintaining the voltage of a power distribution system under the occurrence of balanced three-phase short-circuit fault and unbalanced single-phase to ground short-circuit fault is investigated and analyzed using Simulink/Matlab software.

Short Circuit Fault, Power Quality Improvement, Voltage sag, Dynamic Voltage Restorer (DVR), Synchronous Reference Frame Theory (SRFT)