| Summary: | The DC (Direct Current) distribution system based on the voltage source converter (VSC-DC) has become a research hotspot due to its various advantages. There are many plug-in devices in the VSC-DC distribution system, which may be damaged by the fault current. Therefore, studying the fault current characteristics and current limiting method is one of the key methods to ensure the safe and stable operation of the VSC-DC distribution system. Based on theoretical analysis and simulation calculations, this paper studies the causes, influencing factors, and current limiting methods of the fault current when the pole-to-pole fault occurs at the line side of plug-in devices in a ±10 kV VSC-DC distribution system. Firstly, based on the system topology, the decisive fault condition of fault current and the design principle of current limiting reactor value are analyzed. Secondly, the theoretical calculation methods of fault current and current limiting reactor value which satisfies the breaking capacity of DC circuit breaker are proposed. Finally, the accuracy of theoretical calculation methods is verified by simulation in PSCAD/EMTDC (Power Systems Computer Aided Design/Electromagnetic Transients including DC). The research results could provide the theoretical calculation methods of the fault current and the current limiting reactor value of plug-in devices in the ±10 kV VSC-DC distribution system.
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