| 摘要 |
PURPOSE:To enable measurement of the partial discharge generating position in a cable not affected by the joint of a cable by providing a second tuning frequency besides the first tuning frequency. CONSTITUTION:When a partial discharge occurs at a point B of a cable 10, the pulse signal thereof first goes to the measuring terminal of the cable 10 and the first wave is detected and amplified with an amplifier 14 of the first tuning frequency f1 to be outputted to a measuring device 16. On the other hand, a pulse signal due to partial discharge also goes to the far end to be the second wave, which is detected and amplified with an amplifier 19 of the second turning frequency f2 to increase the amplitude thereof and fed into the cable 10 again to be transmitted to the measuring end. Then, the time difference between the pulse signals is calculated with the measuring device 16 from outputs of the amplifiers 14 and 15 to measure the distance to the position where a partial discharge generates. The position can be detected accurately as signal which reached the far end from the point where the second wave, namely, the partial discharge generated and again arrived at the measuring end thereby enabling the measurement of the correct position.
|
