Research On A CAN-Bus-Based Prefabricated Substation Automation System

Prefabricated Substation has following advantages: short construction period , quick investment benefit, , less area requirement, capable of embedding in the load center, and improvement in the power quality, favoring of urban landscape, less repetition investment etc. Hence, it has got extensive application in reform of city and rural area power system. The continuously development of social economy leads higher and higher request in security, reliability and durative of electricity power supply. As the end link of power distribution, the prefabricated substation has attracted more and more attention. To overcome the inherent disadvantages of traditional prefabricated substation automation system , it is necessary to research and develop a new automation system based on computer and communication technologies. In this thesis, a project of XBZ intelligent prefabricated substation was carried out, and a CAN-bus based prefabricated substation automation system was developed. The outlines of the thesis are as follows:1. The design of main power diagram, structure, function and technical parameter of automation system of prefabricated substation in general are introduced.2. The research on CAN bus was carried out and based on this, a communication protocol of CAN bus which defined in application layer was put forward, this protocol was the foundation of communication inside the automation system.3. The working principle of AC sampling and the measure theory of electricity parameter are discussed, including the analysis of synchronous method of AC sampling, calculation formula of electricity parameter that is fitted to Intelligent Measure and Control Unit (IMCU), and the discussion on square root algorithm.4. According to the requirement of prefabricated substation automation system, the hardware and software design of Intelligent Measure and Control Unit is presented.5. The application of OPC (OLE for process control) and design of an OPC data accessing server are discussed. This OPC server can make the supervising host computer independent of IMCU's communication protocol, so that the supervising host computer become an opening software basis.The debugging and testing result has shown that AC sampling of the IMCU reachs design aim, CAN bus works well, verifying the validity and correctness of the design.