| 摘要 |
<p>PURPOSE:To make certainly the discrimination of an inside signal from an outside signal by judging internal discharge to have generated when the signal of a fixed value or less is detected about the rise time of a high frequency signal induced in a ground tank. CONSTITUTION:A detector 1 detects the high frequency signal induced in a ground tank 15, 16 to output it to a detecting device 12. This signal is inputted into a peak time measuring circuit 3 through a high frequency amplifier 2, and the rise time until the output level arrives at a peak value is measured. The measured result is inputted into an arithmetic circuit 4, and the number of generating times of signals in which rise time is a fixed value or less is computed. The rise time is generally in the range of 1 to 5 nanoseconds in the case of internal discharge, and short compared with the general value, 50 nanoseconds or more, of an external discharge, therefore, if the peak time of the circuit 4 is set, for example, to 10 nanoseconds or less, only the generation of signal of a peak time shorter than 50 nanoseconds is counted and the number is displayed on a display 5. From this counted value, the existence of the internal discharge can certainly be judged, and when the number of detected times is over the fixed value, it is judged to be an abnormality within a gas insulating apparatus.</p> |
