The Design Of Electronic Transformer System Based On SOPC

The increasing demand of the economic development in power system,promotes the development of the electric Power Technology.Electrical equipment should meet certain new requirements as a result of the development and application of high voltage transmission technology,ultra high voltage transmission technology,smart grid technology and digital substation technology.As a kind of most important high-voltage equipments in power system, power transformer is applied in relay protection,system metering and analysis of power system.It has a close relation with the security and reliability of power system.Traditional electromagnetic transformer has exposed a series of shortcomings such as high insulation requirement,magnetic saturation,ferroresonance,small dynamic range,narrow wave band, etc.These shortcomings predestined that the traditional electromagnetic transformer will be replaced by other types transformer with new technology.In recent years,considerable interest has been paid to the electronic transformers which based on the modern communication technology and digital signal processing.With the rapid development of information technology,more and more new technologies are constantly being introduced to electronic transformer with the aim of improving reliability,reducing total life cycle costs.In order to realize seamless connection and interactive operation in the integration of substation automation system,IEC has made the standard system IEC 61850,the standard of communication netwoks and System in Substation.Communication between all of the electrical equipments including power transformers should obey the IEC 61850 standard.The technology of SOPC can integrate processor,memory,peripheral interface and multi-level system design modules into a single chip.Because of its flexibility,efficiency and reusable of design,SOPC technology has been widely used in many fields.In this paper,the development of electronic current transformer at home and abroad is described,and the communication interface of electronic transformer which based on IEC 61850 standard is analysed.Under this basis,an electronic transformer system design scheme which based on single-chip SOPC technology is proposed,then the implementation method on electronic circuit-level is described.A new method of fiber communication which based on synchronous serial communication between the high voltage and the low voltage comes up. By using time-sharing transmission technology on up-fiber,the system transmits synchronous sampling signal and data transmission control signal.And it realizes the synchronous sampling and synchronous serial communication via the combination of a series of wide-narrow pulses.This method reduces the communication error rate and improves the reliability of the serial communication.The synchronization of the electronic transformer merging unit is realized by using GPS PPS.And the digital interface based on IEC 61850-9-1 is realized by using embedded Ethernet technology.Then mathematic models are built and corresponding software/hardware are designed by adopting the thought of modularization。Finally through the test in designed circumstance,the dissertation proves that the model's capability meets the requirements and has high reliability.