Due to the effective integration of large scale photovoltaic and wind power
multi-terminal DC grid gets extensive attention in recent years. Fast and reliable DC transformation and DC fault detection are key techniques in DC grid. A novel DC/DC converter topology with DC fault isolation capability
which is developed from the traditional half-bridge modular multilevel converter(MMC)based DC/DC converter
is proposed. It has additional fault current transfer branch to make the fault current interruption easier
also the corresponding control strategy is proposed. Compared to the traditional topology
when the new topology is connected to more than one DC terminals
the new approach is more efficient in terms of both economy and technology by minimizing the requirements for DC circuit breaker. In the PSCAD/EMTDC based validation
two DC grid scenarios are simulated with DC-side pole to pole short-circuit fault. Simulation results validate the effectiveness of the proposed DC/DC topology
showing that it is suitable for large scale DC grid.