DETECTING METHOD OF INDEPENDENT OPERATION IN DISTRIBUTED POWER SUPPLY

PROBLEM TO BE SOLVED: To separately detect transition from linked operation to independent operation for each distributed power supply giving priority to the detected impedance or admittance changes in the interharmonic wave frequency injected to the system depending on the distributed power supplies connected to the linkage system without limiting the frequencies allowed to the harmonic waves. SOLUTION: Distributed power supplies 6, 6,' within the number of the frequencies the interharmonic waves can take, out of the distributed power supplies 6, 6' connected to the power system (distribution lines 4) for linkage operation are made injection/detection power supplies and inject interharmonic wave to the system in different frequencies for each supply. They are detected to be in independent operation based on the impedance or admittance changes obtained by calculating for each frequency. The other remaining power supplies 6, 6' are made non-injection/detection power supplies and regarded as operating independently from the voltage changes of the interharmonic wave injected to the system from one of the injection/detection power supplies.