The Research And Design Of Electronic Transformer In Application Technology

In recent years, with the obvious improvement of rating voltage and transmission capacitance in power system, conventional ferromagnetic transformers have several drawbacks, which can not keep up with the development requirement of power system.With the high-speed development of digital signal processing, optical fiber transmission and intelligent transducer technology, electronic transformer becomes the study hotspot to scientific research academy and transformer field.In this paper, on the reference of a great deal of documents domestic and overseas, the whole scheme design of electronic transformer are finished based on Rogowski coil and accurate capacitor voltage divider. Firstly, the principal and parameters calculation of Rogowski coil and its applications in current measurement are studyed in power system high-frequency and low-frequency. The response characteristics of steady and transient state are also analyzed. In order to compensate the phasic difference between primary and secondary signal, a new-stype integral circuit is designed. Secondly, the principal of accurate capacitor divider is studyed. For the self-resonance of ECVT, the advantages and disadvantages of several dampers are compared. The transition response characteristic of ECVT and its influence factors are introduced. Thirdly, for the anti-disturbance problem, the hardware and software of high-voltage and low-voltage area are designed based on ADSP-BF535. The digital signals are transmitted in high speed between high-voltage and low-voltage area by the optical transceiver module. A mixed design mode which combined the advantages of self-providing power supply and Li-ion battery is designed to make the transformer run steadily during a high voltage halt or in an insufficient current state. Finaly, considering the interface with controditional and future measurement and protection equipments, the electronic transformer designed has analog and digital output. This paper points out that the design of merging unit is the key element in realizing the digital interface, proposes a new method using FPGA to perform the main functions, and analyzes the international standard for the digital interface between merging unit and secondary digital equipments.The electronic transformer based on DSP and optical fiber transmission technology has the characteristics of ferromagnetic saturation avoiding, broad dynamic range, simple insulation configuration, small buck, light weight, high...