| 摘要 |
PURPOSE:To provide a digital relay having an inspection circuit capable of detecting not only the malfunctioning of not outputting a trip signal but also the malfunctioning of outputting a trip signal by mistake. CONSTITUTION:A plurality of trip signal output circuits which output trip signals by the operating signals of detecting parts 10 or by the trip inspection signals of inspection circuits 20 are provided, and the result of the logical product of each trip signal is given to a trip circuit, and an inspection circuit 20 outputs trip inspection signals not overlapping successively. Accordingly, even if any circuit malfunctions, their logical product becomes zero and no trip signals are outputted, but if a detecting part 10 outputs an operating signal, a trip signal is outputted. And an automatic inspection circuit for checking the inspection signal of each inspection circuit 20 with a response signal corresponding to this is added, and the nonoperating malfunctioning of each trip signal output circuit is detected. Or a full-time monitor circuit which checks the operating signal with a response signal corresponding to this is added to detect the malfunctioning of each trip signal output circuit outputting a trip signal by mistake. |
