Research Of Electronic Transformers Merging Unit

With the great development of digital converting stations and intellectualized power net, the electronic transformers are used more and more. Merge unit is a pivotal equipment used in digital converting stations as the digital interface of electronic transformers. The study and design about merge unit means great deal to the using of digital converting and the development of digital converting stations.The status of digital converting stations, electronic transformers and merge units have been introduced in this essay. On the basis of analysis of the Communication network and systems in substations IEC61850, design and research about the module of digital converting stations and merge units have been discussed. According to the function of merge units defined by IEC61850 and IEC60044, a merge unit has been divided into three parts which are the synchronous function module, the data acquisition module and the Ethernet communication module. Then according to the requirement of the modules and the whole system, a new design of merge units based on ARM&FPGA has come out in this essay, and the Special Communication Service Mapping Sample values over unidirectional multidrop point to point link has been chosen as the communication protocol between Merge unit and secondary security device. After that, four chief achievements have been gained, those are presenting the design of software and hardware about every module in the merge unit, using the interpolation method and the sampling pulse method to realize the synchronous function module of the unit, analysing the data frame which is based on Protocol IEC61850-9-1 and deciding the program flow ofμC /OS?C.Following the debug of the hardware circuit, the experiments of correction on the merge unit have been done to check the integrity and the accuracy class of the data transmitted. Moreover, comparing with interpolation method, the sampling pulse method has been proven to be more stable in the result of the measuring experiment. Furthermore, Conclusion of the design and the promising development of merge units have been presented at the end of the essay.