INSULATION ABNORMALITY DIAGNOSING EQUIPMENT

摘要

PROBLEM TO BE SOLVED: To improve detection sensitivity of partial discharge by enabling discriminating electromagnetic waves generated by partial discharge from external noise, in an insulation abnormality diagnosing equipment of an electric apparatus. SOLUTION: A judging part 27 detects external noise by using a noise antenna 14, selects a specific number of frequencies wherein external noise is low, in the diagnosis frequency band of 300-1000MHz, and determines the selected frequencies as the diagnosis frequencies. In the course of diagnosis process, the judging part 27 uses detected signals of the diagnosis frequencies out of the frequencies, which are detected by an abnormal electromagnetic wave detecting antenna 13, and judges whether insulation abnormality exists. As a result, insulation abnormality can be diagnosed by using only the electromagnetic waves caused by a partial discharge.