A power compensation apparatus for compensating for power of a power system to be allowed to transmit from at least one or more power sources to a load, the power compensation apparatus comprising: a first system connected to the power system to compensate for active power and reactive power of the power system; a second system connected to the first system to store power necessary for compensating for active power and reactive power; and a third system connected to the second system to generate power to be stored in the second system, wherein the first system includes: a converter connected to the power system to convert power; a capacitor connected to the converter and charged with active power of the power system or the power of the second system; a first controller configured to control the converter and the capacitor; a first switch element between the converter and the capacitor; a second switch element between the capacitor and the second system; and a third switch element between the converter and the second system, wherein the second system includes: a power storage apparatus configured to store active power of the power system or the power generated by the third system; and a second controller configured to perform data communication with the first system and to control the power storage apparatus, wherein the first controller is configured to control the converter to supply power stored in the capacitor as active power to the power system when active power is supplied, wherein the first controller is configured to control the second system to supply power stored in the power storage apparatus as active power to the power system, if the charge amount of the capacitor is insufficient, wherein the first controller is configured to determine whether reactive power is compensated for based on a voltage of the power system, and to control the converter to supply reactive power to the power system or to absorb reactive power from the power system, and wherein the second controller is configured to control the third system to receive power generated by a renewable energy source included in the third system and to store the received power in the power storage apparatus, if the amount of power stored in the power storage apparatus is insufficient. a first system connected to the power system to compensate for active power and reactive power of the power system; a second system connected to the first system to store power necessary for compensating for active power and reactive power; and a third system connected to the second system to generate power to be stored in the second system, wherein the first system includes: a converter connected to the power system to convert power; a capacitor connected to the converter and charged with active power of the power system or the power of the second system; a first controller configured to control the converter and the capacitor; a first switch element between the converter and the capacitor; a second switch element between the capacitor and the second system; and a third switch element between the converter and the second system, a converter connected to the power system to convert power; a capacitor connected to the converter and charged with active power of the power system or the power of the second system; a first controller configured to control the converter and the capacitor; a first switch element between the converter and the capacitor; a second switch element between the capacitor and the second system; and a third switch element between the converter and the second system, wherein the second system includes: a power storage apparatus configured to store active power of the power system or the power generated by the third system; and a second controller configured to perform data communication with the first system and to control the power storage apparatus, a power storage apparatus configured to store active power of the power system or the power generated by the third system; and a second controller configured to perform data communication with the first system and to control the power storage apparatus, wherein the first controller is configured to control the converter to supply power stored in the capacitor as active power to the power system when active power is supplied, wherein the first controller is configured to control the second system to supply power stored in the power storage apparatus as active power to the power system, if the charge amount of the capacitor is insufficient, wherein the first controller is configured to determine whether reactive power is compensated for based on a voltage of the power system, and to control the converter to supply reactive power to the power system or to absorb reactive power from the power system, and wherein the second controller is configured to control the third system to receive power generated by a renewable energy source included in the third system and to store the received power in the power storage apparatus, if the amount of power stored in the power storage apparatus is insufficient.