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.