The Development Of Distribution Automation Terminal

This paper mainly analyses the demands on distribution power automation terminal, studies its structure, develops it with a top-down design. Firstly, according to the development prospect of distribution power automation, the thesis discusses necessary functions, performances and configuration demands on distribution power automation terminal. An implementing scheme of Distribution power Automation Terminal Unit (DATU) is given. The software and hardware on DATU are presented. To describe the hardware, function diagram of every module is given; the followings are principles of circuits and measures to improve the system's performance. Interfaces between microprocessor and the functional modules are implemented with Complex Programmable Logic Device (CPLD), which simplifies structure of the circuits. By this means the circuits can be easily controlled, therefore the reliability of the system is improved. To describe the software, preemptive kernel and the kernel based on time-sharing are analyzed. A special real time schedule on the base of the two kernels is adopted to manage the periodical tasks and the asynchronous events. All kinds of software modules are explained. The way by which the user's programs are loaded is given. Finally, the experimental result of the unit indicates that it is highly reliable and real-time and meets the requirement of the system performance.