Phase control device

A phase control device to be applied to a three-phase circuit comprising a three-phase transformer including star-connected primary windings having a grounded neutral point and delta-connected secondary or tertiary windings, and a three-phase breaker that allows the three-phase transformer to be turned on by a three-phase power supply and disconnected from the three-phase power supply, the phase control device suppressing an excitation rush current generated in the three-phase transformer when the three-phase breaker is turned on, the phase control device comprising:

• a closing controller that closes any one of three phases of the three-phase breaker as a closing first phase earlier than the other phases and closes the remaining two phases after the closing first phase is closed;
• a closing-order determiner that determines the closing first phase on a basis of residual magnetic fluxes of the respective phases in the three-phase transformer;
• a target-closing-phase/time determiner that determines, on a basis of a pre-arc characteristic and a closing time variation characteristic of the three-phase breaker, a target closing phase and target closing time of the closing first phase and target closing phases and target closing times of the remaining two phases;
• a closing-time calculator that calculates a closing time of each of the three phases of the three-phase breaker, the closing time being a required time from an instruction to close each phase until each phrase becomes a closed state;
• and
• a table that stores, as a median of the closing time variation characteristic represented by a normal distribution, the closing time of each phase calculated by the closing-time calculator.