Patent attributes
An inrush-current suppressing device includes: a residual-magnetic-flux calculating unit that calculates a residual magnetic flux in a reference phase of a three-phase transformer while assuming a maximum magnetic flux level generated at a time of applying a rated voltage as 1 PU based on a measurement result of a transformer-voltage measuring unit before and after opening a three-phase circuit breaker; a stationary-magnetic-flux calculating unit that calculates a stationary magnetic flux in the reference phase of the three-phase transformer with reference to the maximum magnetic flux level obtained as the 1 PU based on a measurement result of a power-supply-voltage measuring unit, in response to a closing command to the three-phase circuit breaker; and a control unit that actuates a switch of the three-phase circuit breaker corresponding to the reference phase at a timing when the stationary magnetic flux and the residual magnetic flux in the reference phase match each other.
