| 摘要 |
PURPOSE:To surely detect a partial discharge by receiving an electromagnetic wave of the frequency range from 1 to at least 1,000MHz at the place provided between the outer face of a winding and the inner face of a shield case, and detecting a voltage signal corresponding to the intensity. CONSTITUTION:When the partial discharge is generated in the winding 3, the electromagnetic wave of the main frequency range between 1 to 1,000MHz is emitted to the inside of a tank 4. This electromagnetic wave is reached to a detecting head 5 and crossed each other, then the voltage signal corresponding to a reception intensity of the electromagnetic wave crossed each other is outputted from the head 5. The signal outputted from the head 5 is amplified in an amplifier circuit 9 and forwarded to a spectrum analyzer 10, wherein the signal level of the frequency range from 1 to 1,000MHz is strongly indicated. By confirming this indication, whether the partial discharge is generated in the winding 3 or not can be detected. An outcoming noise is not reached to the head 5 because the tank 4 is formed with a metal, thereby the outcoming noise can be prevented. |
