Study On Digital Output Interface Of Electronic Transformer

Current and voltage are elementary parameters in power system. As new measuring instruments, electronic current transformer (ECT) and electronic voltage transformer (EVT) have been rapidly developed recent years attributing to their remarkable advantages: smallness,lightness,no ferromagnetic saturation,board band width and compatibility with interfaces of microprocessor based protection.The IEC standards have furthered the progress of ECT/EVT development. After introducing the fundament of ECT/EVT and their framework, this thesis presents the important component of electronic transformer's digital interface——merging unit. The merging unit's functional characteristics are analyzed in this thesis. And a new DSP and FPGA based method is given according to merging unit's characteristics. Combining the high speed and parallel processing of FPGA and the flexibility of DSP, the function of data receiving, data processing and Ethernet communication are realized in merging unit. The idea that software is solidified in FPGA and hardware is soften in DSP is embodied. The function of digital calibration is designed for eliminating electronic transformers'system error partially. The prototype of combined current and voltage transformer including merging unit is verified by National High Voltage Measuring Center. At the end of this thesis, the method experiment the merging unit is introduced, and the experiment results are also presented. Meanwhile a brief analysis of the experiment results is given to verify that this scheme is available.