In high voltage DC power supply system (HVDC) system, the fast response breaker is required. Semiconductor circuit breaker is paid attention as one of the key technology in HVDC. However, in some condition, the semiconductor circuit is malfunctioned. When malfunction occurs, unexpected large current is flown to the other normal line. In this paper, the malfunction suppression of semiconductor circuit breaker is described. It demonstrated by using MATLAB/Simulink Moreover, the demonstrated results are confirmed by experimentally.