The Research On Scheme Of Electronic Transformer’s Secondary Interface

With the application and development of digital substations, the digital of substationequipment is an inevitable trend. As an important measurement equipment of powersystem, the transformers is becoming more and more smart, there are a lot of newtransformers such as the optical and electronic. Thus the method of electronictransformers and the secondary equipment’s interface is a key point of digital substation.In this paper, the background of the digital substations is discussed, the author hasresearched the composition of digital substation system, studied the relationship betweenvarious devices, discussed the importance of research on the electronic transformer’ssecondary interface, compared the research between home and abroad. With IEC61850and related standards, made an analysis on the electronic transformer digital interfacefeatures, merging unit functional model, and the solution based on ARM&FPGAembedded processor platform. With reference to IEC61850-9-1standards forcommunication protocol to achieve the electronic transformer with the secondarymetering, protection and control equipment such as point to point communication. Thearticle described the hardware and software design on the merging unit samplingsynchronization control module, the serial data receiver module and Ethernetcommunication module. Meanwhile, according to the actual situation, the authorproposed an analog output interface, in order to fit with traditional substation secondaryequipment. Then the solution based on TMS320F28335digital control platform isdescribed, for which the voltage control module of the software and hardware circuitswere discussed in detail. The incremental PID control algorithm for voltage closed-loopcontrol is also discussed, analysis and calculation was given to the class AB poweramplifier circuit.According to the solution discussed in the article, experiments for testing the mergingunit and analog voltage output interface are discussed, the experimental data showed thatthe proposed merging unit and analog voltage output interface can meet the0.2levelaccuracy standard of electronic transformer in IEC60044-8. In the concluding part, the author made a review of the contents of this article, raisedthe need for improvement in and further research directions.