Abstract: The problem of voltage unbalance and its impacts on sensitive loads is well known. To solve these problems, custom power devices are used such as dynamic voltage restorer (DVR), which is most efficient and effective modern device. This paper discusses a review of the researches on the Dynamic voltage restorer (DVR) for power quality Improvement in power distribution networks. Sensitivity industrial loads, critical commercial operations, Utility distribution networks affected from different types of outages and service interruptions and which results in financial losses. This paper describes DVR principle of operation, basic component, DVRs topologies system in distribution system, types of DVR control strategies, and compensation techniques.