Research Of Electronic Current Transformer Calibration System

Digitized substation technology development, promoted the electronic transformer technology development, it has also attracted the attention of many researchers in electronic transformer calibration device research. After in-depth research of electronic transformer principle and signal transmission, using virtual instrument company’s USB-6211data acquisition card, the merging unit based on FPGA technology, and Microsoft Visual C#software development platform, developed a new system for electronic transformer’s digital and analog calibration.Firstly, this paper introduced the principle and output type of electronic transformer and the definition of ratio error, phase error and composite error, gave the algorithm theoretical analysis of the calibration, and put forward the whole framework of calibration system.Secondly, in the hardware part, this paper introduced the data acquisition card of the analog channel and the comparison of Analog signal acquisition mode, discussed the analysis of communication protocols of the digital channel, discussed the realization method of the each function module of the merging unit based on the FPGA technology of the Xilinx’s Spartan3E series, gave the flow chart of data processing in embedded system of the merging unit. In the software part, it elaborated the software module design of the analog and digital calibration, software design of the data process, the development of the SQlite database using of storing the calibration results, and the software design of time delay testing in the digital channel.Finally, it verified that the calibration system is feasible, based on calibration of the electronic transformer about the0.1accuracy class.