Research on non-communication protection of distribution line considering new energy access

Abstract

The large-scale access to new energy sources turns the traditional single-power radiation distribution line into a complex network. At the same time, the fault characteristics of new energy sources will also cause the change in the magnitude, direction and distribution of short-circuit current in the distribution network. It leads to the misoperation or refusal of the traditional three-stage. Scholars at home and abroad have researched distribution network protection considering new energy access. On the one hand, the impact of new energy access on current protection can be reduced by limiting the grid connection capacity of new energy sources or using short-circuit current limiter. On the other hand, improving the protection performance by changing the protection scheme. This paper begins with a brief analysis of a two-phase fault in a distribution line connected to a DG. Then proposes a new protection scheme based on non-communication protection. Set the grid connection point as the protection segment point, and detect the tide direction and fault direction. If it is determined to be the source side, overcurrent protection will be activated. If it is determined to be the load side, undervoltage protection will be activated. Cooperate with other protection segment points on the distribution line to realize accurate and selective fault isolation. Finally, the correctness of the proposed protection scheme is verified by simulation.