MAGNETIZING INRUSH CURRENT SUPPRESSION DEVICE

摘要

According to one embodiment, a magnetizing inrush current suppressing device is configured to measure a three-phase alternating current flowing from the power supply bus to the load, detect a first interruption phase as a phase of an electric current which is interrupted first among the three phases, detect a phase of a phase voltage zero point through which a phase voltage of the first interruption phase of the three-phase AC voltage passes when changing from the same polarity as that of an electric current immediately before interruption of the first interruption phase to an opposite polarity, and close the circuit-breaker at a phase within 60° from the detected phase.

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 while a load is connected to the three-phase transformer to suppress a magnetizing inrush current, comprising:
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 current measurement unit configured to measure a three-phase alternating current flowing from the power supply to the load; a first interruption phase detection unit configured to detect a first interruption phase as a phase of an electric current which is interrupted first among the three phases, based on the three-phase alternating current measured by the current measurement unit; a phase detection unit configured to detect a phase of a phase voltage zero point through which a phase voltage of the first interruption phase, which is detected by the first interruption phase detection unit, of the three-phase AC voltage measured by the power-supply-side voltage measurement unit passes when changing from the same polarity as that of an electric current immediately before interruption of the first interruption phase to an opposite polarity; and a closing unit configured to close the circuit-breaker at a phase within 60° from the phase detected by the phase detection unit.