| 摘要 |
PROBLEM TO BE SOLVED: To shorten upstream break time without installing a signal line between multifunction protective relays, by setting its own response time longer than the response time from detection of abnormality to break, in case that it detects downstream abnormality. SOLUTION: In case that grounding occurs at point A, the timer of a downstream multifunction protective relay RY2 continues to send the data during clocking of an inner timer to a host computer. An upstream multifunction protective relay RY1 detects the abnormality of the measured value, and sends the data during the clocking of the inner timer to the host computer. Moreover, it monitors the transmission data of the downstream multifunction protective relays RY2, RY3, and RY4, and in case that the CPU of the upstream multifunction protective relay RY1 judges that the transmission data of the multifunction protective relay RY2 is in clocking, the CPU of the upstream multifunction protective relay RY1 switches the operation time of its own inner timer over to long time. |
