PURPOSE: To effectively stop a main engine safely by selecting the starting sequence of auxiliary machines to suppress the speed variation of an emergency Diesel generator within an allowable value.

CONSTITUTION: When the fact that a bus 4 in a station becomes no voltage due to certain reason is detected by a low voltage relay 10, a calculator 12 generates an emergency Diesel generator (DEG) start command 18 and open a breaker 5 of the bus 4. Then, the calculator 12 settles a priority order by the allowable power interruption time of auxiliary machines to set the auxiliary machines to be started to start within the allowable power interrupting time. When the variation in the DEG speed when the selected auxiliary machine is started falls within the allowable value, corresponding load switch 13 is closed. when exceeding the allowable value, the auxiliary machine having longer allowable power interrupting time is first deleted.