Reliability modeling of multi-terminal DC circuit breaker and its impact on multi-terminal DC distribution network

Abstract

In the medium-voltage distribution network, the multi-terminal DC circuit breaker (MTCB) is one of the key pieces of equipment for the connection of multi-terminal converter stations and rapid fault isolation in the future. The reliability level of the multi-terminal DC distribution network is directly impacted by reliability of MTCB. In this paper, the main topological structure and basic working principle of MTCB are systematically analyzed. Then, taking the three-terminal hybrid DC circuit breaker which has been applied in the Zhuhai Tangjiawan “Internet plus” Demonstration Project of China Southern Power Grid (hereafter referred to as Zhuhai Demonstration Project) as an example, the reliability evaluation model of the MTCB is established based on the engineering reliability principle and considering the redundancy level of device. By calculating multi-dimensional reliability index, the reliability of MTCB under different design modes and redundancy levels is analyzed, and the influence of MTCB on the reliability of multi-terminal DC distribution network is further studied based on the minimum cut set method. The influence of the MTCB on the reliability of multi-terminal DC distribution network of Zhuhai Demonstration Project is then studied. Finally, an example of the three-terminal DC distribution network structure of Zhuhai Demonstration Project is analyzed to confirm the accuracy and effectiveness of the proposed model.