Reliable and accurate microgrid protection is significant for micro-grid operation.traditional proection methods can not meet the requirements of microgrid.this paper discusses the problems of the existing micro-grid protection methods. Then proposed a new microgrid protection scheme which uses integrated protection as the main protection of microgrid. this protection scheme is based on bi-directional blocking principle,which will send blocking signal if there is no fault .thus protects microgrid. The proposed method is proved to be an effective method for microgrid.

As the most efficient way of connecting distributed generations which are mainly based on renewable resources to the power grid, the microgrid has been in fast development in recent years. The paper is based on the summary of the present situation of research on microgrid all over the world and the key technology urgently to be solved, and then the advantage and the necessity of developing DC microgrid is analysed in terms of components as well as operation and control of microgrid. At last, an AC/DC hybrid microgrid structure is proposed according to the present circumstances in the distribution network.