Direct current (DC) power grid is effective in solving the problems when high penetration of renewable energy is integrated into the power system. However

the construction of the DC power grid will face challenges in the aspects of technology

equipment and standards. Based on the technical characteristics of DC power grid

three typical application scenarios such as high-penetration renewable energy grid connection

offshore wind power grid connection and DC distribution network are analyzed. The latest research progress of key technologies and core equipments of DC power grids is elaborated. The development direction of DC power grid technology is proposed. The key technologies for the development of DC power grids are analyzed. The future development of DC power grid basic theory system

breakthrough in key technologies and core equipment are pointed out. The above research indicates that DC power grid technology will play a greater role in the global interconnected energy network.