Research On Key Technology Of Distribution Network Communication Mechanism Based On IEC 104 Transmission Protocol

With the increasing importance of distribution network,It is imperative to upgrade the distribution automation system.With the rapid development of modern computer,communication and information technology,The advantages of distribution communication network and Internet connection are further highlighted.The IEC 60870-5-104 protocol came into being.Compared to the traditional serial communication mode,The IEC 104 protocol to realize network communication,not only can effectively use the transmission capacity of optical fiber channel,is conducive to the promotion of standardization of telecontrol protocol,and realize the automation of data networking and power system automation system of the area and the sharing of equipment has the advantages of convenient and rapid maintenance provides important technical support.This paper first introduces the IEC 60870-5-104 protocol,and analyzes the necessity and advantage of using the network communication mode in the current distribution network.Then the article gives the framework of the protocol of IEC 104 protocol,the structure of message and the basic application of the protocol.After that,the communication mechanism of the protocol is studied in this paper,including the protocol's communication process,the maintenance process of the communication connection,and the exception handling mechanism,focuses on three aspects of sequence number maintenance mechanism,counter and timeout timer mechanism.On the basis of deep research,this paper designs the system events and logical events for system communication.In the process of the study of the statute,also found some of the statute of limitations and shortcomings,such as the serial number of discontinuities and break continuingly problems,aiming at these two problems discussed and corresponding optimization scheme.Finally,on the basis of previous design,we completed the development and implementation of ASDU module,event module,timer module and the overall communication framework in communication process,and achieved the desired results through testing.