Incoming current suppression device

A control unit 13 of an electric power supply system causes, responsive to a closing command signal phi B, a switch 2 corresponding to R phase to be thrown at a timing when a stationary magnetic flux and a residual magnetic flux of R phase are coincident with each other and then subsequently causes other switches 3, 4 corresponding to S phase and T phase to be thrown at a timing which is delayed from a zero point of an alternating voltage of R phase by a predetermined phase angle of 0-30 degrees, such that the difference of the stationary magnetic flux and the residual magnetic flux of each of S phase and T phase is minimum. Therefore, an exciting incoming current which flows into a three-phase transformer 8 at a time of throwing a three-phase breaker 1 provided with interpole capacitors 5-7 can be suppressed.