A reactive power compensator includes a control block with a limiter and a primary delay-control block with a limiter that set, based on an output of a voltage sensor, reactive power produced by an SVC to a predetermined value. A reactive power controller sets the reactive power produced by the SVC to the predetermined value controls a voltage of a second bus to fall within a predetermined range. This is performed by adjusting an initial value of the reactive power that is output by the SVC, when a bus voltage of the second bus laid at a position apart from a first bus that is laid at a position near the SVC is deviated from a predetermined fixed range.