Software Design Of Transformer Protection For Digital Traction Substation

The traction substation is used for power conversion, distribution and transmission, which plays an important role in the safe and economical operation of the traction power supply system. As IEC61850 is proposed and applied nationwide in the substation automation system, the protection device based on IEC61850 is becoming really important. In our country, there have already been some digital substations in the power system. However, the research about digital traction substation is much less. So it's important to study the software of protection device based on IEC61850 in the digital traction substation.First of all, the main idea of IEC61850 is introduced, and it is analyzed how the digital substation and some equipments such as unconventional transformer affects protection. The basic connection form of the traction transformer is introduced, as well as the basic principle and the characteristic equation of the impedance-matched balance transformer are analyzed, and related protection setting principle and configuration scheme of traction transformer protection are determined. Data exception handing algorithm is designed, and Fourier algorithm which is a protection foundation algorithm is introduced. According to IEC61850, the protection software for traction transformer protection device is designed based on Windows platform. The software is reasonably divided into several tasks according to its functions, which include the sampling task, the traction transformer protection task, and the communication task. And the corresponding code of each task module is developed. A software test platform is built, on which the software will be tested. It is proved that the tasks of software are divided correctly, and the logical judgment of the protection is accurate.As IEC61850 is researched more and more deeply and is used more and more widely, the microcomputer protection with electronic transformer interface would have a brighter future.