The features of microgrid technology in operation mode

capacity and voltage level

structure mode

connection mode are overall analyzed and summarized. Furthermore

the researching method and thinking of various key technologies about optimization design

operation control

security

economic operation of microgrid are introduced. This paper summarizes the typical characteristics and key technologies of actual microgrids around the world

and makes a prospect of various new technologies and research orientation of microgrid

as well as meaningful suggestions for the future research and development of microgrids in China. This work is supported by National High Technology Research and Development Program of China (863 Program) (No. 2014AA052001) and National Natural Science Foundation of China (No. 61273172).