| 摘要 |
PROBLEM TO BE SOLVED: To return the sampling clock SK of each slave station of a main-rear integrated type protective relay device, in the restoration of a vanished common clock KA of each slave station, from an internal clock KB to the clock KA while minimizing the fluctuation by the slippage between the clock KA and the clock KB. SOLUTION: Each slave station 12 comprises a free-running oscillator 15 for forming the clock KB of the frequency of the clock KA; a means for switching the clock SK from the clock KA to the clock KB in the vanishing of the clock KA to continue the sampling of measurement information; a means for varying the generation interval of the clock KB in long direction or short direction by a fixed length which never causes the wrong detection of a system accident to initially correct the clock SK; and a means for switching and returning the clock KB to the clock KA when the slippage of generation timing between the clock KA and the clock KB is within a prescribed range. |
