Merging Unit Of Electronic Transformer Based On FPGA

With the rapid development of national economy and the technology of computer, communication and automation used in power industry, the intelligent level of power grid has been improved greatly in resent years. In order to realize the targets of security, reliableness, efficiency and environmental protection of power grid, the conception of Smart Grid attract the world wide interest and becomes research emphasis. Smart Grid includes power generation, power conversion, power transmission, power distribution and so on.Smart substation is an important section of Smart Grid. It uses intelligent electronic devices to realize information digitization, networking communication platform and information sharing standardization. Therefore, the substation can complete the basic functions of data collection, measurement, protection, control and so on. Moreover, the smart substation can realize automatic control, intelligent regulation, on-line analysis, decision-making, collaborative interaction and other advanced functions for smart grid.The Smart Grid and intelligent substation technology require better power equipment, and the conventional electromagnetic transformers which have many weak points are difficult to meet the application needs of power system. As the intelligent electronic devices of digital substation, the electronic transformers have broad application prospects. Compared with the conventional electromagnetic transformers, the new electronic transformers have the excellent features of small cubage, light weight, excellent insulation, non saturation, wide-band response, and digitization and so on. At the present time, electronic transformers based on optics and Rogowski coil have entered a practical stage.Merging unit which is the foundation of electronic transformer in intelligent substation has become research emphasis and realized. The core foundation of digital substation is IEC61850 communication protocol. The intelligent electronic devices in substation all adopt this protocol as standard.Based on introducing the server model of merging unit, this paper describes a realization method of intelligent merging unit of electronic transformer on the basis of FPGA in detail. According to the features of modular programming and multitasking of FPGA, this method realized sample pulse synchronization, sample values (SV) receiving, SV processing, Ethernet controller driving, and SV transmitting in single chip FPGA. Data frames transmitted by the merging unit correspond with the protocol of IEC61850-9-1 and IEC61850-9-2. Transmission of the two kinds of data frames can be switched in terms of actual needs. The data frames were captured and analyzed by MMS ethereal software, and the results demonstrate the merging unit has high flexibility and utility value.