Patent ID: 8008810
Filing Date: 2011-08-30
Classification: H01H,H02H

Abstract:
1. A phase-control switching apparatus comprising: a breaker that is connected between an electric power system and a transformer and is controlled to cut off or energize the transformer; a voltage measuring unit that measures each phase voltage between the breaker and the transformer; a residual-magnetic-flux calculating unit that calculates a residual magnetic flux remaining on the transformer; and a control unit that controls a switching timing of the breaker based on the residual magnetic flux, wherein the residual-magnetic-flux calculating unit includes the residual-magnetic-flux detecting unit determines whether to recalculate the residual magnetic flux based on the transformer-voltage change rate and a predetermined threshold while the breaker-switching-state identifying unit detects that the breaker is in an open state, and when it is determined to recalculate the residual magnetic flux, recalculates the residual magnetic flux.