| 摘要 |
An insulation monitoring system is provided to detect leakage current including active leakage current and reactive leakage current like a conventional clamp meter or insulation deterioration alarm. A voltage detecting line inputs commercial AC voltage of a power line to an insulation monitoring system. A voltage detecting device(30) detects a commercial frequency component. A phase shifting unit(300) shifts a phase of a voltage component of the commercial frequency component by 90 degrees. A leakage current detecting device(10) detects leakage current flowing between the power line and the ground. A leakage current amplifying filter unit(40) converts and amplifies the leakage current. A synchronous detecting unit(44) synchronously detects the voltage component detected by the voltage detecting device, the 90 degree shifted voltage component output from the phase shifting unit, and the leakage current output from the leakage current amplifying filter unit. An analog/digital converting unit(61) converts analog values of the voltage components output from the voltage detecting device and the phase shifting unit and the leakage current output from the synchronous detecting unit into digital values. A compensating unit(50) converts a reactive leakage current value detected by the synchronous detecting unit and the 90 degree shifted voltage component into a reactive leakage current component to flow the converted reactive leakage current component to the leakage current detecting device. An operation control unit(62) reads the digital values converted by the analog/digital converting unit, controls the synchronous detecting unit, a setting unit(63), and a memory unit(66), and transmits data to the compensating unit. |
