| 摘要 |
PROBLEM TO BE SOLVED: To facilitate the inside or outside judgment of a relay device in case some abnormality occurs by doubling the monitoring circuit of a relay device so as to judge whether it comes from the inside or outside of the relay device. SOLUTION: In a judgment route in case some analog abnormality occurs at the outside of a relay device 10, the identical analog input is introduced into an input transformer 4, a filter 5, and the monitor computing part 7 of a CPU 6 which are doubled, and both monitoring computing parts 7 detect some analog abnormality. Therefore, by detecting some abnormality with both introduced analog inputs at a judgment circuit part 8, it is judged that abnormality occurs at either of a CT.PT1 which is ahead of the relay device 10, or an input cable 2, and transmits that it comes from external failure, to an outside output 9. It is thus possible to prevent a protecting function of external abnormality from being locked. |
