| 摘要 |
PURPOSE:To realize high speed interruption of a protective relay unit provided with a back-up protective means by ensuring selectivity in the interruption of fault when a three terminal system is protected. CONSTITUTION:The protective relay unit provided with a back-up protective means for protecting a three terminal system transmission line through a stepped time limit distance relaying system comprises means for transmitting the operating conditions 512 of a second stage relay detecting a fault in the direction of an opposing bus including the opposing bus and means 521, 522 for receiving signals transferred from the opposite end, wherein an interruption command is delivered 55 to a circuit breaker on this end on condition that the operation 513 of protective relay on this end and the transferred time. signals 521, 522 have sustained for longer than a predetermined. |
