The development of DC grids faces challenges from DC fault protection. The conventional DC circuit breaker (DCCB) employs metal-oxide varistor (MOV) to isolate the faulted line

in which the fault isolation process is coupled with the energy dissipation process. In this study

a clamping type DCCB (CTCB) using internal capacitors to clamp the converter voltage is proposed. Thanks to the proposed configuration

fault isolation and energy dissipation are decoupled

resulting in a fast fault isolation and low energy dissipation compared to the conventional DCCB. The working principle of the proposed CTCB is presented and verified in a DC grid simulation model. A comparison is made with the traditional DCCB. The fault isolation time can be reduced by 34.5%. The dissipated energy can be reduced by 17.4%. The energy dissipation power can be reduced by 76.2%.