| 摘要 |
PROBLEM TO BE SOLVED: To transmit a supervisory signal to a controller without using a transformer of high breakdown voltage.SOLUTION: The state monitor includes resistance element groups GR, GR, GR, a positive side feeder circuit 3 connected with a joint A, a capacitor Con the output side thereof, a negative side feeder circuit 4 connected with a joint B, a capacitor Con the output side thereof, an intermittent signal oscillation circuit 10a generating an intermittent signal Vwhen the voltage Vbetween a joint C and an interconnection point M exceeds a reference voltage V, an electrooptical conversion circuit 12a for converting the intermittent signal Vinto an optical signal, an intermittent signal oscillation circuit 10b generating an intermittent signal Vwhen the voltage Vbetween the joints A, B exceeds a reference voltage V, an electrooptical conversion circuit 12b for converting the intermittent signal Vinto an optical signal, and a controller 16 for recognizing line-to-ground fault from the output of the electrooptical conversion circuit 12a, and recognizes DC voltage abnormality from the output of the electrooptical conversion circuit 12b. |
