应用IEEE 1588的配电网终端队列时延不对称通信路径的时钟同步补偿算法  

Communication Path Queue-Induced Asymmetry Algorithm for Clock Synchronization on IEEE 1588

作　　者：钱超[1] 徐迅 梅军[1] 喻洁[1] 郑建勇[1] 王勇[2] 稽文路 张明[2] 

机构地区：[1]东南大学电气工程学院,江苏省南京市210096 [2]南京供电公司,江苏省南京市210019

出　　处：《电网技术》2015年第12期3622-3626,共5页Power System Technology

摘　　要：随着配电网对设备之间的同步性要求日益增高,IEEE1588精确时间协议(precision time protocol,PTP)以及网络时间协议(network time protocol,NTP)等定时协议要求对客户和服务器之间的通信路径延迟进行精确的测量,从而实现时间的精确同步。客户现场的精确时间估算是基于一种假设,即网络的物理传播时间的前向和后向时延是相等的,或者说它们之间的差异之前就已进行了相应的校准的。除了物理链路的延迟,通道上的交换/路由设备将引起定时分组排队时延。然而,该队列时延通常在前向和后向上一般并不同,因此引入了由排队引起的不对称(queue-induced asymmetry,QIA)算法作为解决主从时钟间时间误差不对称的方法。提出了一种易于应用于现有的网络设备中且不需要任何路径定时支持的基于QIA补偿的新算法,并基于OPNET仿真平台对该算法的路径时延和时间偏差进行了对比分析,充分证明了其优越性。With increasing demand of time synchronization, IEEE 1588 Precision Time Protocol and Network Time Protocol require accurate measurement of communication path delay between time server and client in order to provide precise timing synchronization. Precise time at client＇s site is then estimated using assumption that forward and backward time delays due to physical propagation through network are equal, or any difference between them is calibrated beforehand. Apart from physical link delays, timing packet experiences queue-induced delay due to switching/routing devices on the path. This queuing delay is usually different in forward and backward directions, thus introducing queue-induced asymmetry（QIA）, which is a major contributor to time error between master and slave clocks if physical asymmetries are calibrated. This paper proposes a new algorithm for QIA compensation not requiring any on-path timing support, thus easy to deploy with existing network devices. Simulation is conducted based on OPNET to verify priority of the new algorithm.

关 键 词：不对称 时延估测 IEEE 1588 时钟同步 QIA补偿算法 OPNET 

分 类 号：TM72[电气工程—电力系统及自动化]