智能电网光测控中IEEE1588透传时钟的研究与实现

发布时间：2018-01-06 15:35

本文关键词：智能电网光测控中IEEE1588透传时钟的研究与实现　出处：《湖北工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：传统变电站中测控设备和一次设备是通过普通电缆线相连、基于模拟信号通信的,每测量一种信号就需要增加一条连线。为了增加信号传递的准确性,并减小连线的复杂度,智能电网从传感到通信过程全面采用全光数字化信号,光测控过程中测控设备和一次设备通过网络连接。然而网络连接方式会带来同步问题。智能电网中目前存在的同步技术有GPS、IRIG-B和串口同步方式,但是它们是基于专用数据线通信的,不能满足网络化和IP化的需求。IEEE1588是基于分组传送的,能够很好的满足网络化的需求,而且其同步精度能够达到亚微妙级。在网络设备中实现IEEE1588透传时钟,能够在连接测控设备和一次设备时对网络设备的延时进行补偿,从而提高测控设备和一次设备的同步精度,符合智能电网光测控的需求。本文介绍了与IEEE1588透传时钟相关的理论知识,包括IEEE1588的基本概念、节点的分类、透传时钟的分类、利用P2P方式和E2E方式实现透传时钟的同步原理。基于透传时钟的原理,本文对影响透传时钟精度的主要因素进行了分析,得出晶振精度是影响透传时钟精度的主要因素,并进一步分析得出在晶振精度确定的情况下可以通过缩短驻留延时和传输延时提高透传时钟的精度。本文在网络设备中实现了IEEE1588透传时钟的硬件和软件系统设计,通过在硬件层对时间同步报文打时间戳,并结合FPGA和CPU对同步报文进行处理,可以将单个透传时钟设备的精度维持在10ns量级。硬件部分CPU选择PowerPC83系列;MAC选择能够在MAC与PHY接口处对出入MAC的IEEE1588报文打时标的芯片;晶振选用TX⑶中的高端型,精度为4.6ppm;FPGA选择赛灵思中高端产品。在硬件的基础上实现了软件系统的设计,CPU上运行的多任务实时操作系统为嵌入式Linux,所做的软件工作是基于已有的PTN软件平台基础之上完成的。分析了利用的软件平台对IEEE1588的支持和PTP报文的处理流程。软件的功能主要包括报文收发模块、时间戳信息的提取以及IEEE1588透传时钟协议的处理。最后对透传时钟的主要性能进行了测试,主要包括功能性测试、性能测试和负面测试三个方面。实验结果得出透传时钟的精度在80ns左右,并且具有一定的容错功能,能够满足应用需求。
[Abstract]:Traditional substation measurement and control equipment and primary equipment is connected by ordinary cable, based on analog signal communication, each signal measurement needs to add a line. In order to increase the accuracy of signal transmission. And reduce the complexity of the connection, smart grid from the communication process of all-optical digital signal. In the process of optical measurement and control, the measurement and control equipment and the primary equipment are connected through the network. However, the network connection mode will bring about the synchronization problem. The current synchronization technology in the smart grid is GPS. IRIG-B and serial port synchronization mode, but they are based on dedicated data line communication, can not meet the network and IP requirements. IEEE1588 is based on packet transmission. It can meet the needs of the network well, and its synchronization accuracy can reach subdelicate level. In the network equipment, the IEEE1588 transmission clock can be realized. It can compensate the delay of the network equipment when connecting the measuring and controlling equipment and the primary equipment, thus improving the synchronization accuracy of the measuring and controlling equipment and the primary equipment. This paper introduces the theoretical knowledge related to IEEE1588 transparent clock, including the basic concept of IEEE1588, the classification of nodes, and the classification of transparent clock. Using P2P and E2E to realize the synchronization principle of transparent clock. Based on the principle of transparent clock, this paper analyzes the main factors that affect the accuracy of transparent clock. It is concluded that the precision of crystal oscillator is the main factor that affects the accuracy of transmission clock. Furthermore, it is concluded that the precision of the transparent clock can be improved by shortening the dwell delay and transmission delay when the crystal oscillator precision is determined. In this paper, the hardware of the IEEE1588 transparent clock is realized in the network equipment. And software system design. By timestamp on the hardware layer, and combined with FPGA and CPU to process the synchronous message. The accuracy of a single transparent clock device can be maintained at 10ns. The hardware part CPU selects the PowerPC83 series; The MAC selects the chip that can mark the IEEE1588 message in and out of MAC at the interface between MAC and PHY. The crystal oscillator uses the high-end type of TX3 with an accuracy of 4.6 ppm; Based on the hardware, the design of the software system is realized. The multi-task real-time operating system running on the FPGA is embedded Linux. The software work done is based on the existing PTN software platform. This paper analyzes the support of the software platform to IEEE1588 and the processing flow of PTP message. The main function package of the software is analyzed. Includes message receiving and sending module. The extraction of timestamp information and the processing of IEEE1588 transparent clock protocol. Finally, the main performance of the transparent clock is tested, including the functional test. The experimental results show that the accuracy of the transparent clock is about 80 ns, and it has some fault-tolerant function, which can meet the application requirements.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM76

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