Phase control switch apparatus

摘要

A phase control switch apparatus incorporating a phase-based break/make controller (80A, 80B, 80C) for protecting a reactive load such as a transformer (10) from transient surge phenomena taking place upon power-supply breaking/making operation. The phase control switch apparatus includes a reference phase detecting unit (82) for predicting phases of the phase-voltage and phases-current waveforms upon closing and opening of the breaker contacts, a residual magnetic flux detecting unit (83) for predicting residual fluxes in each phase of the transformer (10) on the basis of time points at which the breaker contacts of the individual phases were opened in the preceding breaking operation and polarities of the phase-currents immediately before the breakage, an operation control unit (81) for predicting optimal closing time points for the individual phases at which the transient surge can be suppressed to a minimum on the basis of the predicted residual fluxes