| 摘要 |
PROBLEM TO BE SOLVED: To provide a sequence timer holding device in a digital protective relay device capable of obtaining right output without erroneously recovering an output circuit in switching a system fundamental frequency.SOLUTION: The sequence timer holding device includes: a timer 27T which outputs ON in time-up of a timer counter for counting the number of counts corresponding to the system fundamental frequency and outputs OFF in the other case than time-up; a 27 output circuit which outputs the ON/OFF output of the timer 27T as relay output; and timer holding means (a hold circuit (flip-flop) 101 and a NOT circuit 102) provided between the timer 27T and the 27 output circuit, outputting an OFF signal by resetting the output of the timer 27T when a 27 relay is not operated, outputting an ON signal when the 27 relay is operated and the output of the timer 27T is ON, and outputting the ON signal while holding an ON signal output state when the 27 relay is operated and the output of the timer 27T is switched from ON to OFF.SELECTED DRAWING: Figure 1 |
