Network-wide time synchronization based on SDH link transmission

Network-wide time synchronization system is a key technology of electric power industry in recent years. High precision time reference signals transmitted by SDH (Synchronous Digital Hierarchy) network and high precision timing network application realized by PTP (Precious Time Protocol) are being studied at home and abroad. External frequency references are required to rectify the access and transmission delay error of PTP over E1 transmission. Based on the time synchronization demonstration project of electric power communication network and the related experimental data, the influence on transmission timing precision caused by frequency deviation on the SDH transmission link are analyzed. It is demonstrated that the frequency synchronization standard of SDH link is critical to the transmission of time synchronize signals, the networking advises on network-wide time synchronization are proposed to realize the entire network coverage of unified reference time signal.