| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for diagnosing insulation deterioration in a power cable that can detect residual charges in an insulator of the power cable with good sensitivity. SOLUTION: The method for diagnosing insulation deterioration includes: a first process in which AC voltage is applied to the insulator of the power cable and the AC voltage is finished at a zero-cross point to store electric charges in the insulator by final half-wave voltage just before the zero-cross point; and a second process in which the frequency of the final half-wave voltage is lowered from a prescribed frequency to 0 Hz at the time so that the applied AC voltage is smoothly attenuated and is converged to OV, subsequently, AC voltage is applied to discharge the residual charges stored in the insulator, and DC components appearing in a detection circuit at the time is detected as a deterioration signal showing deterioration in the insulator. COPYRIGHT: (C)2013,JPO&INPIT |
