Research on DC Assembled Switch and Its Control Strategy to Improve Reliability of AC-to-DC Distribution System

摘要

On the basis of the original AC distribution line corridor, the AC line can be used as the DC distribution line, which can reduce the project construction cost. In order to improve the reliability of the AC-to-DC distribution system based on the symmetrical monopole structure, this paper proposes a DC assembled switch and its control strategy by using the third line of the original AC line. According to the analysis of three fault situations including single-line fault, two-line fault and three-line fault, it is indicated that the proposed DC assembled switch can realize the normal operation of the DC system under single-line fault, and the continuous operation with fault under two-line fault. Finally, a two-terminal DC distribution system is built in PSCAD/EMTDC. Simulation results verify the effectiveness of the DC assembled switch and the correctness of the theoretical analysis.