INSULATION ABNORMALITY DIAGNOSIS SYSTEM OF ELECTRICAL FACILITY

摘要

PROBLEM TO BE SOLVED: To surely judge presence or absence of a portion with insulation abnormality even when discharging is weak or a distance between an acoustic wave sensor and a discharging point is large.

SOLUTION: The acoustic wave sensor 2 detects an acoustic wave signal generated by a transformer 10. A control circuit 8 extracts a specific frequency component from the acoustic wave signal to detect an envelope curve signal from the signal of the specific frequency component. The control circuit 8 computes a frequency spectrum from the envelope curve signal to compute a Mahalanobis distance D2using the frequency spectrum intensity. The control circuit 8 judges the presence or absence of a portion with insulation abnormality based on the comparison result between the Mahalanobis distance D2and a prescribed threshold.

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