Aiming at the defects of the existing hybrid DC circuit breakers

which are expensive and difficult to be used in multi-terminal power grid

we propose a new hybrid DC circuit breaker topology. In the topology

a combination of a common transfer branch and a diode rectifier bridge is adopted to reduce the number of insulated gate thyristors（IGBTs）

and an additional resistor in series with the transfer branch to reduce the peak value of the fault current. Aiming at this new topology

we analyze its breaking principle in multi-terminal power grid in detail

establish a mathematical model of fault circuit by using the replacement circuit method

and construct a relation expression between fault current and additional resistance. Finally

we establish a simulation model of the new hybrid DC circuit breaker by the PSCAD/EMTDC simulation software. The results show that the number of IGBTs can be effectively reduced by using common transfer branch structure

and the additional resistance of transfer branch can significantly improve the breaking capacity of DC circuit breaker.