Voltage fluctuation suppressing apparatus

According to an embodiment, a voltage fluctuation suppressing apparatus is provided with a power storage device connected to an electric power system, a basic control unit to control an output of the power storage device, a voltage detector to measure a voltage of a connection point to the electric power system, and an output control unit to divide a control amount to be outputted to the basic control unit into a reactive power command value and an active power command value and to output them. The output control unit is provided with a reactive power upper limit value calculation unit, a reactive power calculation/output unit, and an active power calculation/output unit. The active power calculation/output unit outputs 0 as the active power command value, when an absolute value of the control value to be outputted to the basic control unit is not more than an absolute value of an upper limit value of the reactive power command value, and outputs a value that is calculated from a prescribed expression and is not 0 as the active power command value, when the absolute value of the control value exceeds the relevant absolute value. >13 V BASIC < Pr6f UNIT C Qref A:12 F Z2 ---PFre (-X - - - - --- -- - 2 4 ,| B ~~02 ve23 28 ~ ~--- --- - - ~-- ~- - -- ~ - - - - -2 xX2 + 2.. X2 y g--30