POWER SYSTEM STABILIZING SYSTEM

PROBLEM TO BE SOLVED: To suppress the fluctuations in frequency due to the amount of fluctuations in a load on a power system by selecting a power system stabilizing device for suppressing the fluctuations in system frequency according to a calculated amount of fluctuation, and allocating it to power storage and discharge. SOLUTION: A centralized control device 15 is fed with a power detection value P1 of a power system 1 through a signal converter, and simultaneously inputs to an arithmetic operation circuit the detection values P3A, P3B, P3C of power input/output to the power system 1 by power system stabilizers A, B, C. Meanwhile, the detection value P1 of a load is written into pattern memory in a specified sampling cycle, and the cycle of the point of variation in the detection value in the pattern memory and an amount of fluctuation PL are calculated. Furthermore, the timing for the next point of variation and the direction of variation are predicted, and a combination of objects to be operated which minimizes the amount of input/output power is determined. The power system stabilizer selected, based on the result of the determination outputs a target value Pref which corresponds to the amount of a control Pr of an input/output power P3 to a power controller 4 with a target value controller 7. As a result, fluctuations in frequency is suppressed.