| 摘要 |
PROBLEM TO BE SOLVED: To provide a protective relay device for detecting failure of a converter. SOLUTION: The protective relay device includes a converter means 22, having converters 23a, 23b, and 23c for receiving and converting each phase signal as an input from a three-phase electrical apparatus, and a judgment means 29 connected to the converter means 22 for judging the condition of the electrical apparatus on the basis of converted signals. The converter means 22 has a detector 40 connected to the ground of each phase signal of the electrical apparatus for detecting a comparison zero-phase-sequence portion and converting it in the same conversion as the input. The zero-phase-sequence portion detected at the detector 40 by the judgment means 29 are compared with the zero-phase-sequence component from each signal converted by each of converters 23a, 23b and 23c. If these components are different, it is judged that failure is produced in converter means 22. |
