Study Of Testing System For Digital Protection

As IEC61850has become the general international standard of substation communication, sub station information can be shared more and more convenient.In the normal digital substation based on IEC61850, property of information,the transmission medium and the design and operation method of relay protection device changes a lot,the traditional protection test device and test method can not meet the existing demand for testing, especially in digital protection communication performance.Based on the study of the digital protection and the IEC61850standard, this paper has analyzed the transmission methods of the sampling value message and GOOSE message, developed the digital protection test platform based on RTDS and put forward a digital protection test interface design based on FPGA.The main technical characteristics of the digital substation and the communication of the process layer are introduced. The technical characteristics of the digital substation communication is analyzed. Then the communication methods of the process layer and the spacer layer as well as the IEC61850standard are studied, and the basic application technology of the digital substation is mastered. This paper carried out a detailed analysis of the principles of the sampling value message and the GOOSE message, and in-depth studied their transport mechanism, encoding rule and encoding format.The test platform for the fault test experiment of digital protection communication is built by using the RTDS equipment combined with fault occurred device. Then the methods of building the sampling value transfer model and GOOSE message transmission model and the overall experimental model are explained. Based on the above analysis of the transmission principle of the sampling value message and GOOSE message and combined with the new requirements of digital protection test of the digital substation.The overall design program of the digital protection test fault occurred device is put forward, of which the hardware structure based on FPGA and the Ethernet communication module. This paper divided the overall function into the Ethernet transmission module, the group package module and the control module, and discussed the implementation method of each module as well as the RTL-level circuit generated after the software programming Quartus Ⅱ compiled, and tested the performance of fault occurred device and proved it can meet the requirements of the test platform of the digital protection.