Research Of Digital Interface Of Electronic Current Transformer

With the development of power system towards extra high voltage, higher capacity and digitization, it is a necessity to put forward a strict requirement for the measurement and protection facilities in power system. Serious defects of traditional electromagnetic current transformer have emerged; it is difficult to keep up with the development of power system, so that electronic current transformer substitutes the old electromagnetic current transformer is unavoidable. Though it is very different in output form between electronic current transformer and traditional electromagnetic transformer, so how to select and design the interface of the processing level and the bay level becomes the key problem of research.According to IEC60044-8 standard, the realization methods of the digital communication interface for electronic current transformer is researched in the thesis.Data is processed by using the FPGA chip, and it is applied in the data processing of the power system.The processing and bay level module introduces XC3S200 as central processor; it is the bridge from high-speed data sampling system to measurement and control device in bay level. It completes collecting the multi-channels data stream from electronic transformer, then processing and coding the data after packing total frame based on the standard, finally transmitting these data to bay level using fiber. The data stream from the processing level is translated to electronic signal from optical signal, it is decoded,framed and checked up,then transmitted data to industry computer by universal serial bus. The large calculation capability and abundance periphery interface of FPGA are used to the spot data processing and communication that improve the system communication speed further more enhance the real-timeproperty and reliability.Because the Field programmable gate array has high integration and flexible programming with VHDL, it is used to collect these high speed data stream and synchronize to incoming serial data stream in order to decode the data, then unpack the data frame and check.