Research On Networking Mode Of Automation System For Smart Substation

The thesis focuses on networking mode of automation system for smart substation. Differed from the traditional substation, smart substation constructs a new form of automation system. Primary equipment becomes digital and smart with intelligent components. Smart station is used a unified way to model based on IEC61850 standard in order to achieving the goal of information digitization, communication on network and information sharing standardization. In smart substation, automation devices are divided into three layers according to their functions, which are the station controlling layer, the bay layer and the processing layer. The network among those smart devices is established through switches, routers, optical fibers, cables, and other network communication devices. The information is transmitted via Ethernet and meanwhile the analog sample and control signals are transferred into digital signals. Network messages are used in the information sharing and interactive operation between each device. According to the IEC61850 standard, three types of messaging service model are used in smart substation automation system. Manufacturing Message Specification is referenced as the standard for data exchange between the station controlling layer and the bay layer. Sampled Value message is defined as the standard for the control and protection devices to acquire the sample data from the merging unit in the bay layer. Generic Object Oriented Substation Event is quoted to meet the fast messaging requirements, such as the trip signals and the switching signals. The thesis analyzes the data frame structure, length, transmission regulations and network data flow of those three types of message, demonstrates the feasibility of their transmission in the same network, and builds a simulation platform to test. It is verified that the requirements of smart substation automation system can be reached, even when the three types of message transmit in the same network. Then the thesis puts forward three types of typical networking modes for smart substation automation system, and takes Nanjing 220kV Tiebei substation as an example to discuss those three types of networking modes. Meanwhile the thesis analyzes and compares the cost of each mode, and finds out the most reasonable one. Suggestions have been provided for the networking mode combined with the planning and construction idea of the new generation smart substation.