EXCITING INRUSH CURRENT SUPPRESSION DEVICE FOR TRANSFORMER AND ITS CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To control a residual magnetic flux in a transformer since a circuit breaker is shut off by controlling an opening phase of the circuit breaker even when the three-phase transformer with a three-phase three-leg iron core installed in a power system is used.;SOLUTION: An exciting inrush current suppression device for a transformer includes a power source voltage measuring means for measuring voltage of each phase of a three-phase power source and calculating inter-wire voltage; a residual magnetic flux calculating means for calculating an inter-wire residual magnetic flux of the transformer when the three-phase circuit breaker shuts off the three-phase transformer; an opening phase control means for selecting a middle phase of the three-phase three-leg iron core as a control target phase and controlling the opening phase of the three-phase circuit breaker so as to shut off the middle phase at a designated phase; and a closing control means for detecting a voltage zero point wherein the inter-wire voltage is transferred from the same polarity to reverse polarity in relation with the inter-wire residual magnetic flux regarding an inter-wire having the largest inter-wire residual magnetic flux and closing the three-phase circuit breaker at the voltage zero point.;COPYRIGHT: (C)2010,JPO&INPIT