| 摘要 |
<p>PROBLEM TO BE SOLVED: To highly precisely diagnose insulation deterioration of an alternating current electric installation under operation. SOLUTION: Air vibration caused by a partial dischare noise generated by insulation deterioration of an alternating current electric installation is detected using a sound-photoconverting sensor 20, an ultrasonic component serving as a feature of the discharge noise is extracted by a by-pass filter to be envelope-detected, and a Fourier series of a frequency having two times of power source frequencies is found. The found Fourier series is converted into a corresponding discharge amount based on a correlation between a frequency component value having two times of power source frequencies in discharge sounds preliminarily found and stored and discharge amounts, so as to determine a deterioration condition for insulation.</p> |
