MAGNETIZING INRUSH CURRENT SUPPRESSING DEVICE

摘要

A magnetizing inrush current suppressing device (6) for controlling a breaker (2) that opens and closes connection of a transformer (3), which includes a Y-connected primary winding (301) and secondary wiring (302) and a Delta connected tertiary winding (303), and a power supply bus conductor (1) so as to suppress the magnetizing inrush current, wherein a three-phase AC voltage of the power supply bus conductor (1) is measured, steady magnetic fluxes among the three lines of the tertiary winding (303) are calculated, each terminal voltage of the tertiary winding (303) of the transformer (3) is measured, residual magnetic fluxes among the three lines of the tertiary winding (303) are calculated, and the breaker (2) is input simultaneously in three phases at an input target phase, at which the magnetizing inrush current is suppressed, of the phases at which the steady magnetic flux and the residual magnetic flux match between the lines of the residual magnetic fluxes having the smallest absolute value of the residual magnetic fluxes among the three lines.