| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect shift to a sole operation from system operation of a distributed power supply caused by a system interruption by a voltage phase skip detection system, preventing an erroneous detection due to such as noise and load fluctuation of a system. SOLUTION: A detected voltage of a power system (distribution line) is sampled to perform an A/D conversion, sampled voltage data obtained by the A/D conversion is processed through a digital filter, of a system fundamental wave voltage component from the sampled voltage data is repeated and comparison of the phase of the system fundamental wave voltage component of a current cycle with a phase of the fundamental wave voltage component of a reference cycle is repeated using one cycle prior to a predetermined cycle from the current cycle as a reference cycle of an linked phase. If it is detected two times or more as set times from the comparison that when the phase of the fundamental wave voltage component of the current cycle is deviated from the phase of the system fundamental wave voltage component of the reference cycle by a set value or more, a rapid change of the voltage phase is detected and shift to the sole operation of the distributed power supply 1 is detected. |
