In contrast to alternating current (AC) power transmission

direct current (DC) power transmission has a series of advantages

such as low line loss and nonexistence of the problem of system synchronous operation stability. In recent years

with the rapid development of voltage source converter technology with higher voltage

the study on flexible multi-terminal high voltage direct current transmission (HVDC) system

DC transmission and distribution power net

as well as the related key technologies and equipments such as the high-voltage DC circuit breaker (DC-breaker) has captured great attention from the community at home and abroad. The research status of three types of DC-breakers (spoken of as the mechanical type

all-solid-state and hybrid type DC-breakers) and their topologies

working principles

advantages as well as disadvantages are briefly treated. It is concluded that the hybrid type should be the main trend of development for high-voltage DC-breakers. Furthermore

a scheme of hybrid DC-breakers with fault current limiting is proposed

its feasibility verified through simulation. In this scheme the DC-breaker adopts the hybrid solid-state switch (composed of half and full gate-controlled devices in series connection) which is paralleled with a mechanical breaker involving the fault-current-limiting technology. Therefore the rising rate of short-circuit current can be effectively restrained

relieving the requirement on fault diagnosis sensitivity and mechanical breaker speed. Moreover

the series quantities of solid-state switching devices (especially the expensive full gate-controlled devices such as the insulated gate bipolar transistor) in high voltage application

and the technical difficulty and production costs etc will be reduced.