METHOD AND DEVICE FOR DIAGNOSING ABNORMALITY IN GAS INSULATED ELECTRIC DEVICE

PROBLEM TO BE SOLVED: To inexpensively achieve reliable method and device for diagnosing abnormality that can efficiently and accurately distinguish partial discharge for indicating the sign of insulation abnormality being generated inside a gas insulation electric device from external noise forcibly entering from a transmission line or the like, and, furthermore, can estimate distance to a generation source when it is judged that the abnormality is caused by the partial discharge being generated inside the gas insulated electric device. SOLUTION: A high-frequency signal is taken in from a shield electrode 4 of a closed metal container 1, the high-frequency signal is separated for each of a plurality of frequency regions by each of signal separation devices 12a-12c, the level of each high-frequency signal for each frequency region is compared by an operation/display device 13, it is at least judged whether abnormality occurs in a gas insulated electric device or not, and at the same time distance from an observation point to an abnormality occurrence point is judged.