Analysis and Correction Methods for Network Time-delay Error of IEEE 1588 Synchronization Clock

Institute of Electrical and Electronics Engineers (IEEE) 1588 synchronous clock based on Transmission Control Protocol/Internet Protocol (TCP/IP) is used for communication networks timing in substations. The path time-delay error of synchronous message is caused by the communication network transmission. The precision error of IEEE 1588 clock synchronization is analyzed, where the correction methods of path time-delay error of synchronous message are proposed with the diffserv-based packets scheduling model (DPSM). The bandwidth adjustment factor, urgent degree mechanism and the time-delay of synchronous message are determined by setting the priority of the service message queue of the network node. Then the correction methods of oscillation frequency of clock generator are proposed. The IEEE 1588 synchronization clock error is thus corrected. Finally, the high precision network clock hardware platform is built and the test is completed. Experiment results show that the clock has the synchronization precision of nanosecond, and it can satisfy the time synchronization precision requirements of International Electro-technical Commission (IEC) 64850 standard for smart substations.