A reactive power compensation system comprising: a detection unit configured to acquire loading state information of a plurality of loads (21a, 21b, 21c, 23a, 23b, 23c); a reactive power compensation unit comprising a Thyristor-switched capacitor, a Thyristor-controlled reactor, and a fixed capacitor, wherein one or more of the Thyristor-switched capacitor and the Thyristor-controlled reactor are operated according to a control signal to compensate reactive power; a measurement unit configured to measure voltage data, current data, and a phase angle with respect to the plurality of loads (21a, 21b, 21c, 23a, 23b, 23c); and a controller configured to: determine, based on the loading state information, a compensation control mode to be: a power factor compensation mode if it is determined that no load is input, and a flicker compensation control mode if it is determined that the loads are input; control the reactive power compensation unit to perform flicker compensation or power factor compensation according to the determined control mode, and provide the control signal to the Thyristor-switched capacitor to compensate a power factor when no flicker is generated even when the control mode is determined to be the flicker compensation control mode. a detection unit configured to acquire loading state information of a plurality of loads (21a, 21b, 21c, 23a, 23b, 23c); a reactive power compensation unit comprising a Thyristor-switched capacitor, a Thyristor-controlled reactor, and a fixed capacitor, wherein one or more of the Thyristor-switched capacitor and the Thyristor-controlled reactor are operated according to a control signal to compensate reactive power; a measurement unit configured to measure voltage data, current data, and a phase angle with respect to the plurality of loads (21a, 21b, 21c, 23a, 23b, 23c); and a controller configured to: determine, based on the loading state information, a compensation control mode to be: a power factor compensation mode if it is determined that no load is input, and a flicker compensation control mode if it is determined that the loads are input; control the reactive power compensation unit to perform flicker compensation or power factor compensation according to the determined control mode, and provide the control signal to the Thyristor-switched capacitor to compensate a power factor when no flicker is generated even when the control mode is determined to be the flicker compensation control mode. determine, based on the loading state information, a compensation control mode to be: a power factor compensation mode if it is determined that no load is input, and a flicker compensation control mode if it is determined that the loads are input; a power factor compensation mode if it is determined that no load is input, and a flicker compensation control mode if it is determined that the loads are input; control the reactive power compensation unit to perform flicker compensation or power factor compensation according to the determined control mode, and provide the control signal to the Thyristor-switched capacitor to compensate a power factor when no flicker is generated even when the control mode is determined to be the flicker compensation control mode.