MAGNETIZING INRUSH CURRENT SUPPRESSION DEVICE

摘要

An excitation inrush current suppression device (6) for suppressing excitation inrush currents flowing through a breaker (2) of the three-phase collective operation type for opening and closing connection between a power supply bus bar (1) and a modified Woodbridge connection transformer (3) effectively grounded is configured to measure a three-phase AC voltage of the power supply bus bar (1) to calculate prospective magnetic fluxes of the transformer (3), and to measure a three-phase AC voltage on the transformer (3) side to calculate residual magnetic fluxes of the transformer (3) after shutoff, so as to set the breaker (2) closed when polarities of the prospective magnetic fluxes respectively agree with polarities of the residual magnetic fluxes in all of the phases respectively.