A Study Of The Embedded Ethernet In The Substation Automation System

This thesis gives an overview of the evolution and actuality of the substation automation communication system, and analyzes the applied model for the embedded Ethernet in a substation automation system (SAS). With the adoption of the embedded Ethernet technology in the substation automation communication system, an embedded software supporting a couple of Ethernet to run in parallel is implemented in a hardware equipment, formed by an 80296SA microprocessor and a CS8900A network controller and not downloading real-time operating system. In addition, the thesis studies a new method to model the substation automation communication system, and presents a reliable transmission way in a substation with the application protocol control mechanisms of IEC60870-5-104 protocol and UDP (User Datagram Protocol).For the equipment located in the bay layer of a SAS is lowly configured, generally it is difficult to download the RTOS (real time operation system) and the implementation of Ethernet communication protocols. This thesis puts forward an embedded Ethernet communication software implementation structure, characteristics of multi-task, time-sharing and layers. In the software, a space table method with the character of real-time is adopted to manage memory;the messages are organized through a combination with dynamic and static modes;and for the route and address resolution in the equipment located in the bay layer, the equipment just supports the function of address resolution, and the gateway in substation is provided of ARP (Address Resolution Protocol) proxy. This implementation mode greatly reduces the complexity of a system. This thesis also studies some problems, such as the monitoring of failure in a SAS Ethernet, and presents the method of applying ARP to the monitoring of SAS Ethernet failures.The particularity of the product on the electric power requires the SAS LAN (Local Area Network) with highly reliability and real-time. When to design a typical substation, it is vital to examine the transmission performance of a LAN under various conditions, and to provide afoundation of designing the communication network, especially when the Ethernet LAN is used as the communication network of bay layer in a SAS.This thesis analyzes EPOCHS (Electric Power and Communication Synchronizing Simulator), and studies the method of synchronically simulating the traffic in a substation with the PSCAD/EMTDC (Power System Computer Aided Design/Electromagnetic Transients Program including Direct Current) simulator and the NS2 (Network Simulator) software. For the messages bursting out and closely relating to the faults in the electric power systems around the substation, NS2 is used to simulate of SAS communication systems and PSCAD/EMTDC is for electrical systems, which models the time characters of relays and switches operation.In China, a series of named network-103 protocols are proposed. Having cognizance of the limitations of the most commonly scheme in application and implementation, this thesis proposes a new reliable transmission method in a substation with the application protocol control mechanisms of IEC60870-5-104 protocol and UDP (User Datagram Protocol), and gives an implementation of it in the EPOCHS platform.