| 摘要 |
PROBLEM TO BE SOLVED: To provide an isolated operation detector capable of detecting isolated operation in a short time, without injecting reactive power when variation of frequency is very small.SOLUTION: When the lapsed time Tx from the time when a relatively gentle frequency change (first frequency change) is detected, to the time when a relatively sudden frequency change (second frequency change) is detected exceeds a first time T1, a determination unit 23 determines that isolated operation is carried out. Isolated operation can be detected in a short time, by determining presence or absence of isolated operation without waiting for final convergence of frequency, on the basis of a characteristic pattern of frequency variation at the time of isolated operation.SELECTED DRAWING: Figure 1 |
