OVERVOLTAGE SUPPRESSION METHOD AND DEVICE

摘要

Current measurement means inputs single-phase current that is output from current measurement equipment and calculates (current measurement step) the current flowing in the ganged three-phase operation breaker when the ganged three-phase operation breaker interrupts the inductive load. Based on the measurement results of this current measurement equipment, phase detection means detects (phase detection step) a first interrupting phase selected from the three phases of the ganged three-phase operation breaker and the current interrupted point of this first interrupting phase. An open command output means sets a contacts-opening range between the time point obtained by back-calculation of the minimum arcing time for which current interruption is feasible without generating reignition and the current zero-point in the phase that is advanced by 120° phase from the first interrupting phase, starting from the current interrupted point as a base point, and outputs an open command to the three-phase breaker in this contacts-opening range (open command output step).