Development Of The Communication Processor In Subway Substation Automatic System

With the acceleration of the urbanization process in China, the subway construction has become a powerful booster for the rapid growth of national economic. As one of the important subsystems in charge of monitoring tasks during power supply in the subway system, Power Supervisory Control and Data Acquisition (PSCADA) system ensures operation safety of the whole system. In recent years, the International Electro-technical Commission (IEC) has promulgated the IEC61850 standard to achieve the integration of communications of PSCADA system. Although many current subway equipment manufacturers have tried to develop the new intelligent equipment matching with IEC61850 standard, it will definitely take a quite long time before the new equipment putting into usage and entirely replacing the traditional intelligent devices. During this process, it’s possible that the intelligent devices adopting the traditional and the novel IEC61850 protocol connected to the same PSCADA system, which will lead to communications incompatibility in PSCADA system. For solving this problem, the main task in this thesis is to design a communication controller installed in station level of the subway substation automation system. This controller can be the information hub between the power substation and the remote dispatching center to realize the data exchanges and information sharing among devices with different protocols.Firstly, the application environment of the communication controller is analyzed, and its system functions and hardware parameters are confirmed. Embedded communication controller hardware system is established based on ARM using the distributed architecture of "Embedded Core Mainboard+Application Baseboard".Secondly, the protocol transition model, including IEC104 telecontrol, ModBus, IEC103 and IEC61850 protocol, is used to analyze the protocol mapping relation of the communication controller. The protocol processing program is developed by C language, adopting the modular and multithreaded software design methods under the embedded Linux operating system. As the kernel program of the communication controller, this program is mainly responsible for the communication data processing and conversion between different protocols. Meanwhile, the system supervisor is developed as the communication controller’s auxiliary program. It is deigned to mainly complete two tasks and ensure the safe operation of communication controller. The tasks include the management of protocol processing program running status and proofreading of system time.Finally, a simulation test platform is constructed based on the device connectivity in the substation automation system to test the overall function of the communication controller system. The performance of this communication controller has been verified as the information hub of the substation automation system, and successfully solved the problem of traditional and IEC61850 protocol equipment access to PSCADA system.