On-line degradation diagnosis device for power cable and on-line degradation diagnosis method for power cable

摘要

PROBLEM TO BE SOLVED: To highly accurately diagnose insulation deterioration due to water tree while a power cable to be diagnosed is kept in an online state.SOLUTION: An online deterioration diagnosis device of a power cable comprises current detection means for detecting leakage current Ie flowing in a ground line of a shield conductor of a power cable, reference signal generation means for generating a reference signal, phase adjustment means for adjusting a phase of the reference signal, and specific frequency component extraction means for accepting inputs of the reference signal generated by the reference signal generation means and the leakage current Ie detected by the current detection means and outputting an absolute value |I| having the same frequency component as the reference signal, of the leakage current Ie.