Abstract:

According to analysis on action of P546 optical fiber differential protection in 500kV Luxin transmission line No.1 to response the fault occurred

in outside of the zone, it was pointed out that in the dual channels switch over process of the optical fiber protection, the transmission delays of NOKIA

PCM device in the two directions of receiving and sending are different; and the importance of the PCM device in the dual channels mode of the optical fiber

differential protection was explained.

Key words: pulse code modulation (PCM) device, channels switch over, transmission delay