ISOLATED OPERATION DETECTION DEVICE, POWER CONDITIONER USING THE SAME AND ISOLATED OPERATION DETECTION METHOD

摘要

PROBLEM TO BE SOLVED: To provide an isolated operation detection device that can detect an isolated operation of a dispersion type power supply while suppressing variation of a DC component occurring in a power system, a power conditioner using the same and an isolated operation detection method.SOLUTION: A measuring unit 3 measures the frequency F 1 of an AC voltage of a power system 151. A calculation unit 4 determines fluctuation in the frequency F 1 of the AC voltage from a plurality of measurement results of the measurement unit 3. The calculation unit 4 determines a target value representing the magnitude of reactive power X2 to be injected from an injection unit 2 on the basis of the fluctuation of the frequency F1. An adjusting unit 5 injects the reactive power X2 smaller than the target value at the time point of starting injection of the reactive power X2 from the injection unit 2, and increases the reactive power X2 to be injected from the injecting unit 2 with time lapse until the reactive power X2 reaches the target value. On the basis of the frequency F1 measured by the measuring unit 3, the judging unit 6 determines whether the dispersion type power supply 152 is in isolated operation or not.SELECTED DRAWING: Figure 1