Development Of Ditgital Substation Communication Management System

With the rapid development of substation automation technology, digital substation has become a trend. Traditional substation monitoring system is mainly managed by the people, and devices of the system require regular maintenance. Its shortcomings include poor real-time, less reliable and so on. On the contrary, digital substation has simple secondary wiring, reliable transmission of information, high accuracy and other advantages. This will improve the requirement of communication management system of digital substation. Therefore, it is very meaningful to develop the background communication management system of digital substation.Firstly, this thesis describes the background of the subject and the characteristics of digital substation. And then, the thesis describes the three-tier distributed architecture of digital substation control system. According to different communication technologies, the thesis analyzes their communication network structure and secondary equipment layout. After studying the status of the communication management system, the thesis decides to use the modular approach to design the overall structure of configuration software. As an important component module of configuration software, the communication management system uses the spiral model as its development model.Secondly, the thesis describes the content of the digital substation communication between each layer and the requirements of communication speed and network performance. Through analysis of the Modbus protocol, IEC 60870-5 series of protocols and IEC61850 protocol, the thesis describes the design of communication system based on Modbus protocol. The thesis uses Win32 API functions to program serial software, uses asynchronoue I/O technology to improve program executive efficiency, uses multiple threads mechanism to sumchronize the information transmission, and finally uses dynamic link library technology to realize the secondary development of templates for the communication propram of CAN, Profibus and Ethernet protocols. Thirdly, as the core of monitoring software, data management system is composed of configuration database, real-time database and historical database. The main function of configuration database part is to manage static data parameter information, system configuration information and screen information. The part of Real-time database uses FastDB to read and write real-time data fastly, and designs the interface for the monitoring screen and historical database to call real-time data conveniently. The part of historical database uses the binary mode to read and write disks, and optimizes the disk space, read speed and backup operations and so on. In addition, the user management is designed to realize functions of adding users, deleting users and modifying password, this improves the operation safety greatly.Finally, the thesis designs some test cases for the background communication management system of digital substation. After testing the communicaton system using independent path testing method, single-function testing method and subsystem testing method, the communication system has some obvious advantages such as faster updata rate and more small memory usage, compared with Realbridge Configuration Softeare. After insert rate test for real-time database and query test for historical database, the results show that real-time database and historical database have faster rate and less resource than SQL Server 2000. After comprehensive testing for the communications management system, all modules of the system operate normally, this indicats that the background communication management system of digital substation is feasible.