The number of installation of Distributed Generators (DG) such as photovoltaic and wind generations has been rapidly increasing in the world. Penetration of DG can contribute to reduce CO<sub>2</sub> emissions and conserve energy. On the other hand, since reverse power flow from DG to distribution system occurs exceed of the upper limit of adequate range of voltage, various voltage control methodologies have been proposed in order to keep voltage within the secure range. This paper describes several advanced voltage control technologies and shows the trend and future perspective about the control of distribution system with many DGs.