MAGNETIZING INRUSH CURRENT SUPPRESSION DEVICE

摘要

A magnetizing inrush current suppression device (6) controls a circuit breaker (2) that opens and closes a connection between a three phase transformer (3) and a power source bus (1) in a state where a load (7) is connected to the three phase transformer (3) such that a magnetizing inrush current is suppressed. The three phase alternating current voltage on the power source bus (1) side of the circuit breaker (2) is measured and the current for the three phase alternating current flowing in the load (7) from the power source bus (1) is measured. An isolated first phase that is the first isolated of the three phases is detected and a zero point phase (0c) that is passed through when the isolated first phase for the three phase alternating current voltage transitions from the same polarity as the polarity of the current just before isolation of the isolated first phase to the reverse polarity is detected. The circuit breaker (2) is turned on at a phase within 60° from the detected phase (0c).