Research Of Electronic Transformer Calibrator Base On FPGA

Transformer is the important equipment in electric energy metering and relay protection of power system, its precision and reliability is closely related to the power system's security, reliability and economic operation. With the development of power industry, a series of limitations of conventional electromagnetic transformer emerged, while electronic transformer can eliminate those limitations. The electromagnetic transformer to be replaced by electronic transformer is the trend of the development of power industry. Nowaday, electromagnetic transformer calibrator is the mainly transformer calibrator in our country. With the development of electronic transformer, the work for checking electronic transformer is increasingly urgent, thus the work to develop electronic transformer calibrator is imperative.In this thesis electronic transformer calibrator has been designed according to the international standards IEC60044-7, IEC60044-8 and the domestic standards GB20840 [1].7-2007, GB20840 [1] .8-2007. This calibrator adopts the direct method to check electronic transformer, the secondary output signals of the tested electronic transformer and the standard electromagnetic transformer have been tested and compared, and to finish the checking of electronic transformer by comparing of the results. The structure of the electronic transformer and the characteristics of output digital signals have been introduced firstly in this thesis, and then discussed the designed method of hardware and software for electronic transformer calibrator. Use the technology of FPGA in the hardware to design the control circuit of Ethernet controller RTL8019 to realize remote reception of electronic transformer signals and the control circuit of the A/D chip MAX125 to transform the analog signal of electromagnetic transformer to digital signal. Use the SOPC technology of FPGA in the software to design the IP core of RTL8019 and MAX125. The software programming has been completed to control the hardware in NIOS II IDE, quasi-synchronous algorithm and DFT algorithm have been used to process the digital signal. The electronic transformer calibrator has been designed finally.Finally, relevant experiments have been done, 0.5 accuracy class electronic voltage transformer and 0.5 accuracy class electronic current transformer have been tested by the designed electronic transformer calibrator, and the point 20%,100%, 120% of Rated load have been measured. The electronic transformer can be checked by electronic transformer calibrator after analyzing experimental data, and meet the request of the 0.5% ratio error and 20' phase error. This thesis' research provides a powerful theory and practice support for the development of electronic transformer calibrators.