Research On High Precision Time Synchronization System Of Intelligent Distribution Network Based On IEEE1588 Protocol

With the rapid development of China's power industry,the monitoring,control,protection and dispatching of power grids have become increasingly demanding for time synchronization systems.Especially for some monitoring equipment,the required data acquisition accuracy can reach subtle magnitudes.It is difficult to achieve high-precision,reliability,and economical unity in the conventional time synchronization systems.To solve this problem,the IEEE of the United States has proposed the IEEE 1588 Precision Clock Synchronization Protocol(PTP),which can achieve subtle levels of time accuracy at a lower cost.In this paper,based on the application background of capacitor monitoring device,a high-precision time synchronization system based on PTP protocol was developed.This system is not only suitable for monitoring equipment in this paper,but also has a wide application space in the entire power system,and has important research value.First,this article describes several traditional timing methods and analyzes their advantages and disadvantages.Then introduced the PTP clock model,communication model and message type in depth,and elaborated the principle of PTP.Then analyze the performance requirements of the time synchronization system,in order to make the device's accuracy to the subtle level,using the PTP time mode,based on this,designed the overall structure of the synchronization system,and illustrates the architecture of various levels of function.Second,this paper presents a hardware and software design scheme for the time synchronization system.In the hardware design part,select STM32F107VCT6 chip as CPU,which supports running PTP protocol;use DP83640 chip to realize the function of printing time stamp;at the same time,in order to adapt to the application occasion of the system,use WF-2571 module to realize Ethernet to wireless network function,and also analyzed the chip's effect on synchronization accuracy.In the software design part,a brief analysis of the clock port state machine is given first,then the main program of the software system,the best master clock algorithm program,the master clock and slave clock PTP message transceiver processing program are given,at the same time,the article analyzes the encapsulation and parsing process of system packets by the light weight TCP/IP protocol stack.Finally,in order to achieve a higher accuracy of the time synchronization system,the paper analyzes the possible causes of the error in the system.Among them,a method of printing time stamps at the MII interface layer is proposed for the protocol stack jitter error brought by the high time stamp marking layer.Aiming at the uncertain jitter delay generated by the relay equipment,a solution using the transparent clock model was proposed.For the network delay measurement error caused by inconsistent clock frequencies,the crystal oscillator was selected and a closed-loop frequency correction algorithm was proposed.These methods allow the clock synchronization accuracy and stability to be further optimized.