摘要：With the development of power electronic technology, flexible DC distribution system has gradually become a research hotspot. Pole-to-pole short circuit fault is the most serious fault type in DC distribution system. When pole-to-pole short circuit fault occurs in DC side, it will produce a large fault current, which will cause serious harm to DC distribution system. Therefore, it is urgent to install current limiting reactor to limit fault over-current. Aiming at the DC distribution system based on half bridge MMC, this paper analyses the fault mechanism and fault characteristics of pole-to-pole short circuit fault, studies the current limiting effect of the installation position and capacity of current limiting reactor on fault current, and carries out simulation verification in PSCAD / EMTDC platform. The analysis and simulation results show that installing a current limiting reactor at the outlet of the DC side can reduce the peak value of capacitor discharge current, and installing a current limiting reactor at the outlet of the AC side can reduce the overall amplitude of fault current.
