| 摘要 |
An insulation monitoring system is provided to output alarms according to predetermined reference data of leakage current or insulation resistance and to transmit the alarms to a remote place. A commercial frequency voltage detecting unit(31a,31b,31c) converts commercial AC voltage into predetermined voltage. A commercial frequency voltage filter unit(32a,32b,32c) extracts a voltage component of a commercial frequency component from the converted voltage. A commercial frequency 90 degree phase shifting unit(33a,33b,33c) shifts a phase of the commercial frequency voltage. A low frequency voltage detecting unit(34) converts low frequency signal voltage into predetermined voltage. A low frequency voltage filter unit(35) extracts a voltage component of a low frequency component. A low frequency 90 degree phase shifting unit(36) shifts a phase of low frequency voltage. A current/voltage converting unit(41) converts a leakage current component into a voltage component. A commercial frequency current filter unit(43) extracts leakage current of the commercial frequency component. A low frequency current filter unit(45) extracts leakage current of the low frequency component. A commercial frequency digital/analog converting unit(51a,51b,51c) and a low frequency digital/analog converting unit(54) convert digital values of the leakage current components of the commercial and low frequencies into analog values respectively. A commercial frequency multiplying unit(52a,52b,52c) and a low frequency multiplying unit(55) multiply values of the leakage current components of the commercial and low frequencies respectively. A commercial frequency compensating filter unit(53a,53b,53c) and a low frequency compensating filter unit(56) flow the leakage current components of the commercial and low frequencies to a leakage current detecting device(10) respectively. |
