MAGNETIZING INRUSH CURRENT SUPPRESSING DEVICE

摘要

According to one embodiment, a magnetizing inrush current suppressing device includes, a first closing unit closes the circuit-breaker at the notable phase by the first phase determined by the first-phase determination unit, a second-phase determination unit determines a second phase at which the notable phase detected by the notable phase detection unit from the three-phase AC voltage measured by the power-supply-side voltage measurement unit becomes a zero point after the first phase determined by the first-phase determination unit, and a second closing unit closes the circuit-breaker at two phases other than the notable phase by the second phase determined by the second-phase determination unit.

主权项

1. A magnetizing inrush current suppressing device for controlling a circuit-breaker which opens and closes a connection between a three-phase transformer and a three-phase AC power supply and in which a capacitor is connected between poles, to suppress a magnetizing inrush current, comprising:
a transformer-side voltage measurement unit configured to measure a three-phase AC voltage on the three-phase transformer side of the circuit-breaker; a residual magnetic flux DC component calculation unit configured to calculate DC components of residual magnetic fluxes of three phases of the three-phase transformer after the three-phase transformer is shut down, based on the three-phase AC voltage measured by the transformer-side voltage measurement unit; a notable phase detection unit configured to detect, as a notable phase, a phase having one of a maximum absolute value and a minimum absolute value from among the DC components of the residual magnetic fluxes of the three phases calculated by the residual magnetic flux DC component calculation unit; a power-supply-side voltage measurement unit configured to measure a three-phase AC voltage on the power supply side of the circuit-breaker; a first-phase determination unit configured to determine a first phase at which the notable phase detected by the notable phase detection unit from the three-phase AC voltage measured by the power-supply-side voltage measurement unit takes a peak value having a polarity opposite to a polarity of the DC component of the notable phase of the residual magnetic flux calculated by the residual magnetic flux DC component calculation unit; a first closing unit configured to close the circuit-breaker at the notable phase by the first phase determined by the first-phase determination unit; a second-phase determination unit configured to determine a second phase at which the notable phase detected by the notable phase detection unit from the three-phase AC voltage measured by the power-supply-side voltage measurement unit becomes a zero point after the first phase determined by the first-phase determination unit; and a second closing unit configured to close the circuit-breaker at two phases other than the notable phase by the second phase determined by the second-phase determination unit.