Abstract:In order to enhance the robustness and stability of the three-terminal HVDC control & protection system of Yun-Gui interconnection project. In addition to the use of two redundant point-to-point communication modes between each station, as with the normal HVDC project, it is also required that when the two redundant lines between two stations are all communication abnormal, the state data of the control&protection system between the two stations can be forwarded through the other station to achieve no interruption. Based on this, this paper expounds the network architecture design and working mechanism of two feasible schemes, then analyzes their respective advantages and disadvantages. Finally, determines the communication scheme between three terminal, and the direction of further research is proposed.