| 摘要 |
PROBLEM TO BE SOLVED: To provide a diagnostic method for a power cable that does not require any dedicated component nor circuit and can diagnose the power cable being applied with a voltage without any power failure.SOLUTION: A diagnostic method for a power cable includes the steps of: measuring a voltage applied to the power cable and a ground current flowing to a shield material; and calculating a capacitive current i(t) and a resistive current i(t) from capacitance and resistance value of the power cable. A current i(t) generated owing to water tree deterioration is calculated from the ground current i(t), capacitive current i(t), and resistive current i(t), and deterioration of the power cable is diagnosed based upon the calculated current i(t) and the applied voltage v(t). |
