Abstract: Low-voltage DC distribution network has the characteristics of short duration of fault current, variable system operation mode and fault current oscillation, which challenges the correct judgment and fault location of relay protection. In this paper, the fault characteristics of low-voltage DC distribution networks are analyzed in detail, and a DC network protection scheme including the current direction comparison method, direction prediction method and extreme value comparison method is proposed. The protection unit with the proposed scheme can quickly locate the fault area and complete the fault clearing and isolation after the DC distribution network fault occurs. In order to facilitate the engineering application of the protection scheme, the generic object oriented substation event（GOOSE） communication is used to realize the information exchange between the protection units, and the protection strategy of"instant memory of single branch, delayed location of multi-branch"is proposed to solve the practical problems such as short duration of fault current and asynchronous data transmission. Real-time digital simulation（RTDS） test results show that the protection can correctly identify the fault area within 5 ms after the fault occurs.