IEEE 1588同步时钟网络时延误差的分析及修正

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

IEEE 1588同步时钟基于TCP/IP技术,采用变电站通信网络对时,受通信网络传输阻塞的影响,存在同步报文传输路径延时误差。文中分析了IEEE 1588时钟同步精度误差;提出了基于区分服务调度模型的同步报文路径延时误差修正方法,通过设置网络节点业务报文队列的优先级,建立了带宽调节因子和紧迫度机制,确定了同步报文的时延,并提出时钟发生器振荡频率的修正方法;实现IEEE 1588同步时钟误差的修正。搭建了高精度网络时钟硬件平台,并完成了测试。实验结果表明,该时钟实现了纳秒级网络对时,能够满足智能变电站IEC 61850标准对时间精度的要求。

IEEE 1588 synchronous clock realized with 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 congestion. The precision error of IEEE 1588 clock synchronization is analyzed, and the correction methods of path time-delay error of synchronous message are proposed with the diffserv-based packets scheduling mod^l. The bandwidth adjustment factor, pressing degrees mechanism and the time-delay of the synchronous message is determined through setting of network node service message priority. Then the correction methods of oscillation frequency of clock generator are presented. The IEEE 1588 synchronization clock error is thus corrected. Finally, the high precision network clock hardware platform is built. Experiment results show that the clock has the synchronization precision of nanosecond, and it can satisfy the time synchronization precision requirement of smart substations of IEC 61850 Std.