The present disclosure comprises: a solid-state circuit breaker, which is arranged between a battery system and a line and includes a semiconductor switch for providing an electrical connection or insulation between the battery system and the line according to the voltage applied to a gate terminal; an interrupter switch for providing a physical connection or separation between the solid-state circuit breaker and the line; and a rack battery management system which controls a gate driver applying the gate voltage, so as to provide insulation between the battery system and the line according to the result of sensing a current flowing between the battery system and the line, and which controls the interrupter switch to physically separate the solid-state circuit breaker from the line.