PHASE MODIFYING EQUIPMENT CONTROL DEVICE AND PHASE MODIFYING EQUIPMENT CONTROL METHOD

Current information (310) is information on a current step being a current time step for a power system including a reactive power supplier. A plurality of pieces of future information (311 to 31n) are a plurality of pieces of information on a plurality of respective future steps being a plurality of future time steps for the power system. Power installation information (320) is information on installations constituting the power system. An optimal power flow problem is a problem subject to optimal power flow for the power system. The optimal power flow problem is formulated by an objective function and a plurality of constraint expressions based on the current information, the plurality of pieces of future information, and the power installation information. The calculation unit (303) performs the optimal power flow to determine a variable for the objective function. The control command (306) is set based on the variable determined by the optimal power flow. In at least one of the objective function and the plurality of constraint expressions, amounts of variation of an input of the reactive power supplier at the current step and the plurality of future steps of the reactive power supplier are accumulated.