Residual magnetic flux estimation method and residual magnetic flux estimation device for transformer

摘要

A residual magnetic flux estimation device 1 includes a DC power-source control device 11 which controls a DC power source 300 to apply a DC voltage across two terminals of a connection that is a secondary winding or a tertiary winding, a voltage measuring device 12 which measures a terminal voltage at the primary side of a three-phase transformer 200, a computing device 13 that determines a phase having a high voltage between the two phases other than the phase to which the voltage is applied, and a residual magnetic flux measuring device 14 that measures a phase-to-phase residual magnetic flux between the two phases other than the high-voltage phase, and estimates a measured value of the phase-to-phase residual magnetic flux as a maximum residual magnetic flux in the measurement-target three-phase transformer.