In order to solve problems such as high cost and poor current limiting effect in most conventional hybrid DC circuit breaker

we propose an assembly DC circuit breaker based on pre-charged capacitors which mainly contains a converter-part and a line-part

both of which consist of pre-charged capacitors. The converter-part is installed on the DC outlet side of converter station in DC grid

and the line-part is on each DC transmission line. This hybrid breaker provides an arc-less breaking condition to mechanical breaker branch through pre-charged voltage of capacitors and can suppress fault current effectively. The topology

working principle

control strategy

and comparison between the proposed and existing schemes are described in detail. Besides

the feasibility and effectiveness are validated by building a three-terminal DC model in PLECS. The results show that the proposed DC breaker can not only cut off the DC fault line

but also avoid collapse of bus voltage

ensuring the normal operation of non-faulty lines. Especially in future multi-terminal DC system

the shared converter-part will greatly save the equipment cost due to the common part at the converter site.