Multi-Terminal DC Line Fault Recovery With Fault Self-Clearing and Analysis of Converter Station Online Exit Strategy

In recent years, UHV, large-capacity, multi-terminal and flexible DC transmission technologies have developed rapidly. As a UHV hybrid three-terminal DC project that has been put into operation, the stable operation and fault ride-through capability of the Kunliulong (Kunbei-Liuzhou-Longmen) DC project has received more and more attention. Starting from the structure of the three-terminal DC system, this paper analyzes the self-clearing process of the system fault after the line fails, and then analyzes the three-terminal DC line fault recovery and the logic of the on-line withdrawal from the station. Finally, a three-segment DC model was built to simulate the process of system failure recovery and online withdrawal from the line after different types of faults occurred on the line.