| 摘要 |
PURPOSE:To detect accurately a dielectric dissipation factor abnormal part in a very short part by detecting the part of a cable where the surface temperature rises in accordance with the generation of heat in the dielectric dissipation factor abnormal part. CONSTITUTION:A power cable 1 is wound around a drum 3 provided in a measuring position only by one layer. For example, 200-450 kV measuring voltage is applied to the cable 1. If the dielectric dissipation factor abnormal part exists in the insulator of the cable 1, this part generates heat to raise the surface temperature of the cable 1 and the temperature of this part is higher than that of the other normal parts. A thermography detector 2 which detects the temperature without contacting is arranged around the drum 3 in the measuring position so that this detector can be moved in directions of arrows A and B to scan all of the surface of the cable. Thus, even the dielectric dissipation factor abnormal part in a part very shorter than the overall length of the cable to be measured is detected accurately.
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