| 摘要 |
PROBLEM TO BE SOLVED: To provide a deterioration diagnosis method of a low voltage cable capable of determining the deterioration state such as crack occurring of the low voltage cable simply and accurately in a short time. SOLUTION: In this deterioration diagnosis method of the low voltage cable, an insulation resistance change just after application start is measured by applying a direct-current voltage to the low voltage cable 1, and it is determined that deterioration occurs when a discharge pulsation rate defined by a following expression exceeds 1%: the discharge pulsation rate=(the maximal value of the insulation resistance-the minimal value of the insulation resistance)/the maximal value of the insulation resistance. Preferably the direct-current voltage to be applied is 500V or higher, and preferably the insulation resistance change is measured within a range of 20-60 seconds after start of voltage application. COPYRIGHT: (C)2007,JPO&INPIT
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