Research Of Time Synchronous System On Distribution Network Based On IEEE 1588 Synchronization Technology

In order to alleviate the pressure of energy and to improve energy structure optimization, the recent research of smart grid has shifted from the intelligent substation to the intelligent distribution network. Because the time synchronization accuracy of smart distribution network is not high, and with the development of distribution automation, safe and stable working environment for the distribution network clock synchronization accuracy put forward higher requirements. In order to ensure the convey of the demand from master distribution substation to distribution terminal and the convey of monitoring data from distribution terminal to master distribution substation, the paper introduces IEEE 1588 protocol. Because of its fiber-optic Ethernet communication reusable, low-cost, multi-purpose and the clock synchronization accuracy can be achieved microsecond level, etc., IEEE 1588 protocol can be obtained a wide range of applications.Firstly, the paper compares the advantages and disadvantages of smart distribution network communication mode in a variety of communication methods, and select optical fiber communication as the most appropriate way of communication; the advantages and disadvantages of communication technology when comparing the various intelligent distribution School, and a detailed comparison of the advantages and disadvantages of the NTP and PTP protocol packets when the time clock technology, the actual distribution network clock synchronization, the access layer select EPON optical fiber technology and with the best results when it is synchronized when the IEEE 1588 protocol.Secondly, this paper introduces the basic use as well as the software simulation processes mechanisms of OPNET. The actual distribution network topologies were studied to establish distribution network node clock model based on the IEEE 1588, and the model for the clock node simulation is verified. Each packet types and formats of the PTP and NTP are defined, and verify the superiority of PTP compared to NTP from two aspects of end-to-end time delay and time offset.Finally, two IEEE 1588 clock synchronization schemes:communication path queue-induced asymmetry algorithm for clock synchronization on IEEE 1588 and improved IEEE 1588 synchronization scheme on the clock offset estimation applied in distribution network are studied in this paper. Since the use of IEEE 1588 clock synchronization protocol is based on the assumption that the link delays caused from the process that packets sent from master clock to slave clock and from slave clock to master clock are the same. However, communication path queue-induced asymmetry algorithm for clock synchronization on IEEE 1588 is used to solve problem of how to improve clock synchronization accuracy under the condition that link delays of forward and backward are not the same. In addition, improved IEEE 1588 synchronization scheme on the clock offset estimation take use of additional packets of different packet sizes to overcome asymmetric links and random delays due to the most common delay approximately subject to Gaussian distribution or exponential distribution, in both two cases the distribution using the improved algorithm to verify the superiority of clock offset estimation is simulated.